Slow-speed mechanical-liquid piston compressor-expansion

Abstract

SLOW-MOUNTING MECHANICAL-LIQUID PISTON COMPRESSOR-EXPENSOR The slow-moving mechanical-liquid piston compressor-expander (1) comprises a liquid cylinder (8) that pivots about a tilting axis (9) and in which a hydraulic piston (10) translates. The piston is fixedly attached to a connecting rod (11) connected to a crank (26) of a crankshaft (24) whose axis of rotation is parallel to the tilting axis (9). Piston guiding means (23) maintain the connecting rod (11) and the hydraulic piston (10) always parallel to the liquid cylinder (8). These two form a variable hydraulic volume (12) filled with a working fluid (13) that communicates with a gas and liquid reservoir (14) in which heat exchange and accumulation means (16) are housed. The reservoir (14) and the fluid (13) form a variable pneumatic volume (2) in which is compressed or expanded a working gas (5). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Slow liquid-mechanical piston compressor-expander

[0001] The present invention relates to a slow liquid-mechanical piston compressor-expander.

[0002] Various compressors are used to compress gases in many areas of human activity, whether in industry, agriculture or transport, but also in the residential or commercial sector, particularly to produce heat or cold by means of heat pumps.

[0003] Whether it is a question of producing the compressed air necessary for machines or processes, or of ensuring the operation of heat pumps intended for heating or air conditioning, the efficiency of compressors is a determining factor which has a strong impact on energy consumption.

[0004] In most applications, the heat produced during the compression of a gas constitutes an irrecoverable energy loss. For said applications, the ideal compressor would be an isothermal compressor, i.e. one which evacuates, as it is produced, the heat resulting from the compression of the gas in order to minimize the work required for said compression.

[0005] However, in practice, producing a perfectly isothermal compressor is impossible because in order to release the heat resulting from the compression of a gas as it is produced, there must be a temperature difference between said gas and a heat absorption well.

[0006] It is however possible to approach isothermal compression by using heat export means positioned at the heart of the gases, said means exposing as much as possible a large heat exchange surface to said gases, imparting to the latter turbulent movements favorable to heat exchanges by convection, this while confining any emission of heat by radiation in a closed enclosure and allowing time for heat exchanges to occur.

[0007] However, quasi-isothermal compression is not sufficient to guarantee a compressor high efficiency because non-thermodynamic energy losses are inevitable and must be minimized.

[0008] Among said non-thermodynamic energy losses are mechanical losses by friction of the compressor itself or those linked to its accessories, pressure losses also called “load losses” occurring either at the level of the inlet and outlet flaps or valves of said compressor, or at the level of the conduits which connect said compressor to the points of consumption of the compressed gas or even, the possible internal or external leaks in said compressor.

[0009] As part of the ecological transition, heat pumps that integrate a gas compressor occupy an essential place because they can heat and air-condition buildings at a lower energy cost, by taking renewable heat from the environment.

[0010] With global warming raging worldwide and due to changes in lifestyles, air conditioning in buildings alone already consumes more than ten percent of the electricity produced worldwide, a share that is set to grow significantly in the coming years both in proportion and in volume, to the point that the efficiency of heat pumps represents a major energy issue.

[0011] The same applies to the heating of buildings, which alone absorbs more than twenty percent of the world's primary energy and which, in the coming decades, is destined to make massive use of low-temperature heat pumps, these being the most efficient.

[0012] The principle of heat pumps currently used in the world is based mainly on the change of state, from vapor to liquid or vice versa, of a refrigerant fluid whose saturated vapor pressure is adapted to the targeted heating or refrigeration temperature range, and to the pressures that the installations can withstand.

[0013] State change or phase change refrigeration cycles have the advantage of a high heat or refrigeration power density because they exploit the latent heat of evaporation or condensation of a refrigerant fluid by modulating the pressure and temperature of said fluid so that it evaporates or condenses.

[0014] In the current state of the art and technology and taking into account the economic, technological, physical and production constraints of heat pumps, state change refrigeration cycles remain by far the most efficient.

[0015] However, not all refrigeration cycles involve changing the state of a specially formulated refrigerant.

[0016] For example, the Brayton-Joule cycle, also called the Bell-Coleman cycle, provides for the isentropic compression and expansion of a gas without change of state, with, after said compression, transfer of heat by said gas to a colder environment at constant pressure and with, after said expansion, extraction of heat by said gas from an enclosure to be cooled, also at constant pressure.

[0017] However, the practical efficiency of the Bell-Coleman cycle remains low, with in practice a coefficient of performance barely higher than one and often even lower than one, unlike heat pumps with change of state and refrigerant fluid, whose coefficient of performance can peak at four, or even five to one, which means that for one unit of energy invested, up to four to five units are recovered. energy in the form of heat or cold.

[0018] Due to its low practical energy efficiency, the Bell-Coleman cycle is mainly used only when compressed air is naturally available, which may be the case in airplanes, and on board some trains.

[0019] Unlike Bell-Coleman cycle heat pumps, due to their high efficiency, refrigerant and change-of-state heat pumps are widely used for heating or cooling buildings.

[0020] And yet, the efficiency of refrigerant heat pumps remains well below the ideal Carnot efficiency which, taking the temperature differences usually used to carry out the measurements, would give a coefficient of performance greater than twenty while the best heat pumps currently on the market deliver a coefficient of performance of five.

[0021] But the ideal Carnot efficiency is only an indicator of the maximum efficiency theoretically accessible because it does not take into account the temperature differences necessary for heat exchanges to take place, nor the mechanical and practical constraints of the construction of heat pumps.

[0022] There would, however, be a significant advantage, due to the scarcity of energy and the climatic and ecological issues linked to said energy, in maximizing the efficiency coefficient of heat pumps used to produce heating, air conditioning, or refrigeration as close as possible to the ideal Carnot efficiency.

[0023] Provided that a suitable and efficient compression and expansion machine is available, it is indeed possible to approach the efficiency of the ideal Carnot cycle.

[0024] To achieve this objective, the compressor of said machine must compress a gas in two successive stages.

[0025] The first stage consists of an adiabatic compression which takes place until the temperature of said gas is high enough for the latter to be able to release heat, for example, to a building heating circuit, while the second stage is an isothermal compression during which the temperature reached by said gas at the end of adiabatic compression is maintained during the remainder of the compression of said gas, gradually releasing to said heating circuit the heat produced by said isothermal compression, and this, until said gas is discharged from said compressor.

[0026] Then, the expander of said machine must expand the gas which has been previously compressed according to the reverse process to that which has just been described, also in two successive stages.

[0027] The first step consists of an adiabatic expansion which occurs until the temperature of said gas is low enough for the latter to be able to draw heat for example in the environment outside said building, while the second stage is an isothermal expansion during which the temperature reached by said gas at the end of adiabatic expansion is maintained during the remainder of the expansion of said gas, by gradually taking from said environment the heat necessary to maintain said temperature during the remainder of said isothermal expansion and this, until the discharge of said gas from said expander.

[0028] One of the advantages of such a heat pump is that it no longer requires the use of polluting, toxic or combustible refrigerants, some of which destroy the ozone layer or produce a powerful greenhouse effect.

[0029] No longer depending on refrigerants is all the more important since the regulations plan to ban, from the year 2030, refrigerants whose global warming potential is greater than or equal to one hundred and fifty times that of carbon dioxide.

[0030] These regulatory provisions will reduce the number of refrigerants that can be used in conventional heat pumps, and will significantly impact the technology of said pumps, and even increase the cost price of said pumps.

[0031] The most likely substitute for the refrigerants currently used in conventional heat pumps is carbon dioxide, which is a non-polluting gas with a low specific global warming potential, but whose main disadvantage is high operating pressures of more than one hundred atmospheres, which makes the tightness and safety of the installations more difficult to guarantee.

[0032] We therefore understand the interest in reproducing as faithfully as possible the ideal heat pump cycle of Sadi Carnot, by producing a quasi-isothermal volumetric compressor and expander which use a fluid which remains in the gaseous state throughout the entire cycle.

[0033] This route is only possible by imposing a stable set temperature on the gas during its compression or isothermal expansion, which can be achieved with a medium which stores heat directly in a compression or expansion chamber, said medium being associated with means which export said heat during the compression phase, or which import said heat during the expansion phase.

[0034] Several concepts describe compressors or expanders close to isothermal with means of storing and importing or exporting heat.

[0035] This is the case, for example, of the quasi-isothermal machine described in patent GB2534244, said machine comprising a piston which is oriented downwards and which has a structure for absorbing and restoring heat, said piston compressing a gas in a variable volume in the bottom of which resides a constant volume of fluid.

[0036] According to the invention of patent GB2534244, said piston compresses or expands said gas while forcing the latter to cool or heat up in contact with the heat absorption and restitution structure, said structure being able to be made up of metal sheets which, when they are outside the liquid, exchange heat with the gas, while when they are immersed in said liquid, they exchange heat with the latter.

[0037] According to the invention of patent GB2534244, the liquid remains approximately immobile unlike liquid piston compressors in which the liquid is on the contrary mobile, which implies that said liquid is not subjected to decelerations too far from Earth's gravity under penalty of causing cavitation and panic of said liquid.

[0038] On the contrary, the invention of patent GB2534244 thus makes it possible to manufacture a compressor or a rapidly rotating expander without driving the liquid into motion, which has the advantage of giving said compressor or said expander a high volumetric power density.

[0039] It is noted that the particular configuration of patent GB2534244 proposes a relatively conventional connecting rod and crank system for actuating the piston carrying the heat absorption and restitution structure.

[0040] Another approach is to move a liquid via a piston which translates in a cylinder as provided in patent CN111734604, said liquid, unlike patent GB2534244, submerging a static heat sink.

[0041] Like patent CN111734604, numerous publications also report liquid pistons which alternately force a gas and a liquid to pass through a porous medium or a heat accumulation and restitution system.

[0042] This technical approach is notably adopted by various research programs dedicated to energy storage systems in the form of compressed air, for example intended to accumulate renewable energy produced by offshore wind turbines.

[0043] It is clear from most of these devices that the compression or expansion efficiency depends strongly on the total heat exchange surface between the gas, the liquid and the heat absorption and restitution structures, whatever their nature, but also on the time allowed for said exchanges to take place.

[0044] To promote said exchanges, it is therefore preferable to produce slow-rotating compressors or expanders, in return for a lower power density.

[0045] In addition to the time allowed for heat exchange to occur, the advantage of slow-rotating compressors or expanders is that they allow time for the gas transfer to take place, so as to limit pressure losses at the inlet and outlet ports of said compressors and expanders.

[0046] Indeed, if the latter rotate slowly, their effective thermodynamic pressure-volume diagram will be close to the ideal theoretical diagram because it is less distorted by the transfer of gases, and the practical efficiency of a heat pump integrating said compressors and expanders will be closer to the maximum theoretical efficiency accessible according to the ideal Carnot cycle.

[0047] Because in fact, the inertia forces which reduce the performance of the controlled valves and flaps responsible for transferring gases into or out of a compressor or an expander evolve more or less with the square of the rotation speed of said compressor or said expander.

[0048] This results in a delay in the opening and / or closing of said flaps and valves which is detrimental to the efficiency of the thermodynamic cycle.

[0049] As a consequence of the above, a slow-rotating single-phase heat pump which compresses and expands a gas according to the Carnot cycle will a priori occupy more volume than its conventional equivalent whose refrigerant fluid successively passes from the gaseous state to the liquid state and vice versa, and whose compressor operates at high speed.

[0050] The problem with slow-rotating compressors and expanders is that at the same power, the mechanical parts that constitute them are subjected to higher forces than those that constitute their faster equivalent, and that the large dimensions of said parts that result from said forces generate high energy losses through friction.

[0051] In addition to the large size of said parts, the disadvantage of the slow rotation of said compressors or expanders is that it is unfavorable to the establishment of a hydrodynamic lubrication regime between said parts, whether for example at the friction interface of a piston in a cylinder, or at the pivot connections between said piston and a connecting rod, between said connecting rod and the crank of a crankshaft, and between the latter and a crankcase.

[0052] It would therefore be very advantageous to implement liquid pistons coupled with means of exchange, storage, restitution, import and export of heat, by means of slow machines with very high mechanical efficiency which allow a sufficiently long time on the one hand, for thermal exchanges to maximize their efficiency, and on the other hand, for the transfer of gases to minimize energy losses.

[0053] Such a configuration would make it possible to produce high energy performance heat pumps, delivering an efficiency closer to that of the ideal Carnot cycle than their conventional counterparts which operate with a refrigerant fluid with a change of state, and requiring for example only atmospheric air and water to operate.

[0054] It would be possible, for example, to obtain from said configuration a coefficient of per performance coefficient of the order of seven, where under the same measurement conditions and in the same environment the coefficient of performance of the best refrigerant heat pump on the market would be of the order of five.

[0055] However, as previously described, to obtain such a difference in efficiency, it is necessary to achieve quasi-isothermal compression and expansion by promoting thermal exchanges as much as possible during said compression and said expansion, limiting as much as possible losses by transfer, losses by internal or external gas leaks, and limiting as much as possible losses by friction.

[0056] For example, the coefficient of performance of a single-phase Carnot cycle heat pump, given its need to compress a greater quantity of gas than its counterpart with a refrigerant fluid with a change of state, is necessarily very sensitive to the energy efficiency of its mechanical transmission device, said efficiency, if it is insufficient, having the consequence of giving said single-phase Carnot cycle heat pump a lower efficiency than that of its said counterpart.

[0057] Indeed, as a single-phase Carnot cycle heat pump must compress a greater quantity of gas than its counterpart with a changing-of-state refrigerant, the coefficient of performance of said single-phase heat pump is very dependent on the energy efficiency of its mechanical transmission device for compression and expansion of the gas.

[0058] If said efficiency is insufficient, said single-phase heat pump will have a lower coefficient of performance than that of its refrigerant counterpart.

[0059] This sensitivity to the mechanical compression and expansion efficiency of a single-phase Carnot cycle heat pump is all the greater when, for example, a coefficient of performance greater than five is targeted.

[0060] For example, a single-phase Carnot cycle heat pump that delivers ten kilowatts of thermal power with a coefficient of performance of five requires an external energy input of two kilowatts in the form of mechanical work.

[0061] If the mechanical efficiency of said single-phase heat pump is poor and forms a mechanical loss of one kilowatt, the coefficient of performance of said pump drops from five to three point three, and the energy bill of the owner of said pump increases by fifty percent.

[0062] In this case, said single-phase heat pump loses all or almost all of its interest compared to its conventional equivalent with a changing-state refrigerant fluid.

[0063] This is why the slow liquid-mechanical piston compressor-expander according to the invention provides an innovative configuration with very high mechanical and volumetric efficiency, coupled with efficient heat exchanges and flows, so as to confer, in particular on the single-phase Carnot cycle heat pumps which result therefrom, a significantly higher coefficient of performance than that of their conventional equivalent with changing-state refrigerant.

[0064] Thus, the slow liquid-mechanical piston compressor-expander according to the invention is mainly intended to produce, on the one hand, compressors and / or expanders with high energy efficiency usable in any field of activity, and on the other hand, heat pumps with a high coefficient of performance.

[0065] The slow liquid-mechanical piston compressor-expander according to the invention results in particular in a heat pump: • Which delivers a higher coefficient of performance than that of conventional heat pumps using a changing-state refrigerant fluid, said pump according to the invention therefore reducing, all other things being equal, the energy required to produce heat or cold; • Whose thermodynamic efficiency is close to that of the ideal Carnot cycle which cannot be exceeded, to the point that in all likelihood, the replacement of said heat pump by another concept can hardly be motivated by an additional improvement in efficiency; • Which does not use any refrigerant harmful to health or the environment, said pump being able to operate for example with atmospheric air or nitrogen and escaping any regulatory or safety constraints relating to the handling, storage or recycling of refrigerants; • Whose operating temperature range is very wide due to the non-dependence of said pump on any refrigerant fluid whatsoever, said pump being able to operate in heating or air conditioning mode in any region of the world without prejudice to its performance; • Simple in design, to the point that the pump can be produced in practically any country in the world in workshops with a modest technical level, in particular by assembling low-cost components, easily produced, or widely available on the market; • Whose simple mechanical configuration allows maintenance without great technical skill, and at lower cost; • Which allows any qualified plumber-heating engineer to create a heating and air conditioning network in a simple and accessible way which is easily integrated into buildings and the environment of said buildings, without requiring approval or certification linked to the handling of gases which are dangerous for health and the environment; • Its robust mechanism gives it a lifespan which can reach, subject to the replacement of minor parts, several decades or even more than a century without deterioration in the operation or performance of said pump, such a lifespan constituting an additional advantage of said pump for the environment in comparison with conventional refrigerant heat pumps when analyzing the entire life cycle of said pumps, including manufacturing and recycling; • Which is silent and can be integrated into buildings while producing minimal noise pollution; • The layout of which allows large heat exchange surfaces to be exposed to the environment at low cost, using low-speed, low-energy-consumption, and low-noise motor fans; • The manufacture of which does not require rare or strategic materials, nor high-tech know-how and knowledge;

[0066] It is understood that the slow liquid-mechanical piston compressor-expander according to the invention is intended, in addition to heat pumps, compressors, and gas expanders, for any other application similar in its concept and in its principle which could advantageously take advantage of the particular characteristics and functionalities of said compressor-expander according to the invention.

[0067] The other characteristics of the present invention have been described in the description and in the secondary claims directly or indirectly dependent on the main claim.

[0068] The slow liquid-mechanical piston compressor-expander defining a pneumatic variable volume which forms a compressor or an expander, a working gas being able to enter said volume via an inlet port or exit said volume via an outlet port, comprises: • A liquid cylinder which can, directly or indirectly, pivot around a tilting axis which is perpendicular to the axis of said cylinder and which is secured to a static frame; • A hydraulic piston which can translate in a sealed manner in the liquid cylinder to form with the latter a variable hydraulic volume which is wholly or partly filled with a working liquid; • A gas and liquid reservoir which is connected to the hydraulic variable volume by a communication conduit, so that said reservoir fills mainly or completely with working liquid when the hydraulic variable volume is minimal, and fills partially or completely with working gas when the hydraulic variable volume is maximal, the absolute volume variation of the working gas contained in the pneumatic variable volume forming on the one hand, the pneumatic variable volume, and being on the other hand, approximately equal to the absolute volume variation of the working liquid contained in the hydraulic variable volume; • Heat exchange and accumulation means housed in the gas and liquid reservoir, said means being able, on the one hand, to exchange heat with the working gas or with the working liquid and, on the other hand, to temporarily store all or part of said heat; • Heat export or supply means which take or transfer heat directly or indirectly to the heat exchange and accumulation means and / or to the working liquid and / or to the working gas, said taken heat then being transferred to heating means or said transferred heat having been previously taken to cooling means, said heating means and said cooling means being external to the gas and liquid reservoir; • Filling means which permit or prohibit the passage of working gas from an inlet plenum to the gas and liquid reservoir via the inlet port; • Drainage means which allow or prohibit the passage of working gas from the gas and liquid tank to a discharge plenum via the outlet port; • A connecting rod, a first rod end of which is fixedly secured to the hydraulic piston, said rod being approximately parallel to the longitudinal axis of said piston; • Piston guide means which keep the hydraulic piston and the connecting rod parallel to said cylinder, regardless of the position of said piston in said cylinder; • A crank shaft which can rotate about an axis parallel to the tilting axis in at least one shaft bearing, and which has at least one crank around which a second rod end of the connecting rod is articulated; • At least one drive motor which directly or indirectly drives the crank shaft in rotation; • Means of storing kinetic energy which are directly or indirectly connected to the crank shaft.

[0069] The slow liquid-mechanical piston compressor-expander according to the invention comprises a tilting axis which is a tubular ball joint which terminates the liquid cylinder and the interior of which forms in whole or in part the communication conduit, said ball joint being able to pivot in a sealed manner in a female ball joint housing secured to the gas and liquid tank.

[0070] The slow liquid-mechanical piston compressor-expander according to the invention comprises a tubular ball joint which receives in its center a ball joint axis which is parallel to the tilting axis, said axis being articulated around a ball joint hanger which is directly or indirectly secured to the gas and liquid tank.

[0071] The slow liquid-mechanical piston compressor-expander according to the invention comprises a ball joint hanger which is connected to the gas and liquid tank by means of an articulated hanger connection around which said hanger can rotate.

[0072] The slow liquid-mechanical piston compressor-expander according to the invention comprises a liquid cylinder and a gas and liquid reservoir which form a rigid assembly which pivots around the tilting axis.

[0073] The slow liquid-mechanical piston compressor-expander according to the invention comprises heat exchange and accumulation means which are made up of a porous medium which has porosities into which the working liquid and the working gas enter and exit alternately.

[0074] The slow liquid-mechanical piston compressor-expander according to the invention comprises heat export or supply means which consist of a circulating part of the working liquid, said part leaving the liquid cylinder or the gas and liquid reservoir via a liquid outlet conduit to return to said cylinder or to said reservoir via a liquid inlet conduit, this after having given up heat to the heating means or after having taken heat from the cooling means.

[0075] The slow liquid-mechanical piston compressor-expander according to the invention comprises heat export or supply means which consist of at least one heat exchanger conduit housed in the gas and liquid tank and in which a heat transfer fluid circulates which transports the heat taken or transferred to the heat exchange and accumulation means and / or to the working liquid and / or to the working gas to the cooling means or to the heating means via heat transport conduits.

[0076] The slow liquid-mechanical piston compressor-expander according to the invention comprises heat exchange and accumulation means which consist of at least one liquid spray nozzle supplied by a liquid spray pump, said nozzle being able to atomize working liquid into fine droplets in the internal volume of the gas and liquid reservoir.

[0077] The slow liquid-mechanical piston compressor-expander according to the invention comprises a tilting axis which is constituted by a rolling track which is integral with the static frame and on which a rolling surface can roll which is directly or indirectly integral with the liquid cylinder, a rolling track toothed wheel whose pitch circle coincides with the line of contact between the rolling track and the rolling surface being integral with the static frame and cooperating with a toothed wheel rolling surface which is directly or indirectly attached to the liquid cylinder.

[0078] The slow liquid-mechanical piston compressor-expander according to the invention comprises piston guide means which consist of a sliding pivot connection formed between an external cylindrical surface presented by the connecting rod and a sliding ring which is securely connected to the liquid cylinder via a ring-carrying structure.

[0079] The slow liquid-mechanical piston compressor-expander according to the invention comprises piston guide means which consist of a guide skirt arranged on the periphery of the hydraulic piston, said skirt being able to translate with little play in said cylinder.

[0080] The slow liquid-mechanical piston compressor-expander according to the invention comprises filling means and / or emptying means which consist of at least one compressor valve and / or at least one controlled compressor valve, while in operation, the working gas is expelled from the gas and liquid tank via the discharge plenum under a pressure higher than that under which it was previously introduced into said tank via the inlet plenum, while the heat export or supply means transfer heat to the heating means, so that the pneumatic variable volume forms a compressor.

[0081] The slow liquid-mechanical piston compressor-expander according to the invention comprises filling means and / or emptying means which consist of at least one pilot-controlled expander valve, while in operation, the working gas is expelled from the gas and liquid tank via the discharge plenum under a pressure lower than that under which it was previously introduced into said tank via the inlet plenum, while the heat export or supply means take heat from the cooling means, so that the pneumatic variable volume forms an expander.

[0082] The slow liquid-mechanical piston compressor-expander according to the invention comprises a discharge plenum of the compressor which is connected to the inlet plenum of the expander by a high-pressure gas conduit so that the working gas discharged via the discharge plenum of said compressor is introduced into said expander via the inlet plenum of said expander, the crank shaft of said compressor being directly or indirectly connected to the crank shaft of said expander, said compressor and said expander cooperating to form a heat pump.

[0083] The slow liquid-mechanical piston compressor-expander according to the invention comprises a high-pressure gas conduit which is connected to at least one high-pressure gas reservoir.

[0084] The slow liquid-mechanical piston compressor-expander according to the invention comprises a compressor inlet plenum and an expander discharge plenum which communicate via a low-pressure gas tank to which they are respectively connected by a low-pressure gas conduit.

[0085] The slow liquid-mechanical piston compressor-expander according to the invention comprises an inlet plenum and a discharge plenum which are positioned in the upper part of the gas and liquid tank, the latter itself being positioned above the liquid cylinder so that due to the Earth's gravity, the working gas always leaves the gas and liquid tank as a priority via the discharge plenum, and the working liquid always enters said tank as a priority via the inlet plenum.

[0086] The slow liquid-mechanical piston compressor-expander according to the invention comprises a tilting axis which is made up of a hollow cylindrical axis which has at least one opening radial lumen, said cylindrical axis being positioned above the gas and liquid reservoir, while the inlet plenum and / or the discharge plenum is connected to an annular gas collector which surrounds said cylindrical axis and which encompasses the opening radial lumen so that the working gas can circulate between the interior of the hollow cylindrical axis and the inlet plenum and / or the discharge plenum via the opening radial lumen and the annular gas collector.

[0087] The slow liquid-mechanical piston compressor-expander according to the invention comprises kinetic energy storage means which consist of a low-speed flywheel which is integral in rotation, on the one hand, with the crank shaft, and on the other hand, with a toothed crown which the drive motor drives in rotation by means of at least one crown drive pinion whose primitive diameter is smaller than that of said crown, the latter and said pinion forming a high-reduction gear system, while a high-speed flywheel is directly or indirectly integral in rotation with the crown drive pinion.

[0088] The slow liquid-mechanical piston compressor-expander according to the invention comprises a liquid spray pump which is constituted by a pump cylinder which is arranged in the liquid cylinder and / or in the extension of said cylinder, a pump piston set in motion by the hydraulic piston and / or by the liquid cylinder being able to translate in said pump cylinder.

[0089] The slow liquid-mechanical piston compressor-expander according to the invention comprises a pump piston which has a start-of-stroke button by means of which it is set in motion, said piston being returned to an end-of-stroke stop by a piston return mass.

[0090] The slow liquid-mechanical piston compressor-expander according to the invention comprises a pump piston which is set in motion by means of a setting spring.

[0091] The slow liquid-mechanical piston compressor-expander according to the invention comprises an overflow pump which, at each revolution of the crank shaft, transfers a small quantity of working liquid from an overflow tank to the gas and liquid tank and / or the liquid cylinder.

[0092] The slow liquid-mechanical piston compressor-expander according to the invention comprises an overflow tank which communicates with the discharge plenum, the working gas pressure prevailing in said tank being close to or identical to that prevailing in said plenum.

[0093] The slow liquid-mechanical piston compressor-expander according to the invention comprises an overflow pump which comprises a blind pump cylinder in which an overflow pump piston can translate in a sealed manner, the latter and said cylinder forming a variable overflow pump volume which, when it increases, fills with working liquid from the overflow tank via at least one overflow pump inlet valve and which, when it decreases, discharges said liquid towards the gas and liquid tank and / or the liquid cylinder via a discharge valve.

[0094] The slow liquid-mechanical piston compressor-expander according to the invention comprises an overflow pump piston which is a two-body stepped piston which comprises a large-diameter body which has a large-section face which forms one of the walls of the variable volume of the overflow pump, said stepped piston also comprising, axially opposite the large-section face, a small-diameter body which can translate in a sealed manner in an actuating cylinder whose internal volume is connected directly or indirectly to that of the liquid cylinder, said small-diameter body having a small-section face on which the pressure prevailing in the liquid cylinder is exerted, said stepped piston also offering, at the junction between the large-diameter body and the small-diameter body, a medium-section face from which the small-diameter body emerges, which is connected to the overflow tank,and which is subjected to the pressure prevailing in said reservoir, while a stepped piston stop fixes the maximum volume of the variable overflow pump volume and a two-body piston return spring tends to push the two-body stepped piston towards its large section face.

[0095] The slow liquid-mechanical piston compressor-expander according to the invention comprises a discharge valve which comprises a valve actuator piston which can translate in a sealed manner in a valve actuator cylinder and which has, firstly, an axial valve actuating face which communicates with the overflow tank and on which the pressure prevailing in said reservoir, said face being able to lift an overflow valve from an overflow valve seat when the valve actuator piston moves towards said face, which has the effect of putting the variable volume of the overflow pump into communication with the gas and liquid reservoir and / or the liquid cylinder via said overflow valve, and secondly, an axial face on the liquid cylinder side which communicates with the liquid cylinder, on which the pressure prevailing in said cylinder is exerted, and which can come into contact with a stop on the liquid cylinder side when the valve actuator piston moves towards said axial face on the liquid cylinder side, while an actuating piston return spring tends to push the valve actuating piston towards its axial valve actuating face,and that an overflow valve return spring tends to bring the overflow valve back into contact with the overflow valve seat with which it cooperates, the force produced by the actuating piston return spring being greater than the force produced by the overflow valve return spring.

[0096] The slow liquid-mechanical piston compressor-expander according to the invention comprises an overflow pump piston which is a two-body stepped piston which comprises a large-diameter body which has a large-section face which is connected to the overflow tank and which is subjected to the pressure prevailing in said tank, said stepped piston also comprising, axially opposite the large-section face, a small-diameter body which can translate in a sealed manner in an actuating cylinder whose internal volume is connected directly or not to that of the liquid cylinder, said small-diameter body having a small-section face on which the pressure prevailing in the liquid cylinder is exerted, said stepped piston also offering, at the junction between the large-diameter body and the small-diameter body,a medium-section face from which emerges the small-diameter body, said face forming one of the walls of the variable volume of the overflow pump, while a stepped piston stop fixes the maximum volume of the variable volume of the overflow pump and a two-body piston return spring tends to push the two-body stepped piston towards its small-section face.

[0097] The slow liquid-mechanical piston compressor-expander according to the invention comprises a discharge valve which comprises a valve actuator piston which can translate in a sealed manner in a valve actuator cylinder and which has, firstly, an axial valve actuating face which communicates with the liquid cylinder and on which the pressure prevailing in said cylinder is exerted, said face being able to lift an overflow valve from an overflow valve seat when the valve actuator piston moves towards said face which has the effect of putting the variable volume of the overflow pump into communication with the gas and liquid reservoir and / or the liquid cylinder via said overflow valve. border, and secondly, an axial face on the reservoir side which communicates with the overflow reservoir, on which the pressure prevailing in said reservoir is exerted, and which can come into contact with a stop on the overflow reservoir side when the valve actuator piston moves towards said axial face on the reservoir side, while an actuating piston return spring tends to push the valve actuator piston back towards its axial valve actuating face, and an overflow valve return spring tends to bring the overflow valve back into contact with the overflow valve seat with which it cooperates, the force produced by the actuating piston return spring being greater than the force produced by the overflow valve return spring.

[0098] The slow liquid-mechanical piston compressor-expander according to the invention comprises counterbalancing means which replace in whole or in part the piston guide means for tilting the liquid cylinder during rotation of the crank shaft.

[0099] The slow liquid-mechanical piston compressor-expander according to the invention comprises counterbalancing means which are constituted by a counterbalancing mast which, on the one hand, comprises a counterbalancing mass and which, on the other hand, is articulated around a mast axis which is parallel to the tilting axis of the liquid cylinder and which is integral with the static frame, while the counterbalancing mast forms with said cylinder a pivoting-sliding articulation and constitutes an unbalance opposite to that of said cylinder.

[0100] The description which follows with reference to the appended drawings given as non-limiting examples will allow a better understanding of the invention, the characteristics which it presents, and the advantages which it is likely to provide:

[0101] [Fig-1] is a sectional view of a particular configuration of the compressor- slow mechanical-liquid piston regulator according to the invention according to which the tilting axis of the liquid cylinder is a tubular ball joint, the interior of which forms in whole or in part the communication conduit, and which can pivot in a sealed manner in a female ball joint housing secured to the gas and liquid tank.

[0102] [Fig.2] is a sectional view of the slow liquid-mechanical piston compressor-expander according to the invention, the liquid cylinder and the gas and liquid reservoir of which form a rigid assembly which pivots around the tilting axis.

[0103] [Fig.3] is a three-dimensional sectional view of the rigid assembly as shown in [Fig.2] according to a variant of the slow liquid-mechanical piston compressor-expander according to the invention, an overflow pump being attached to the gas and liquid tank.

[0104] [Fig.4] is an exploded three-dimensional view of the rigid assembly shown in [Fig.3], without the overflow pump.

[0105] [Fig.5] is a pressure-volume diagram of the thermodynamic cycle of a pump heat consisting of a compressor and an expander each formed by the slow liquid-mechanical piston compressor-expander according to the invention.

[0106] [Fig.6] is a three-dimensional overall view seen from the front of a pump heat consisting of a compressor and an expander each formed by the slow liquid-mechanical piston compressor-expander according to the invention.

[0107] [Fig.7] is a three-dimensional overall view seen from the rear of the pump heat shown in [Fig.6].

[0108] [Fig.8] is a three-dimensional sectional view of the heat pump shown in [Fig.6].

[0109] [Fig.9] is a schematic view of the environment and accessories of a pump heat consisting of a compressor and an expander each formed by the slow liquid-mechanical piston compressor-expander according to the invention.

[0110] [Fig. 10] is a schematic sectional view of a liquid spray pump of a compressor formed by the slow liquid-mechanical piston compressor-expander according to the invention, the pump piston of said spray pump being set in motion in a pump cylinder by the hydraulic piston, said pump piston being in the process of sucking in working liquid under the effect of a piston return mass, the pump inlet valve which said pump piston comprises being shown enlarged in an inset.

[0111] [Fig. 11] is a schematic sectional view which shows what happens after [Fig. 10] when the pump piston has come into contact with its suction end stop while the hydraulic piston of the compressor according to the slow liquid-mechanical piston compressor-expander according to the invention has completed its downward stroke and started its upward stroke.

[0112] [Fig. 12] is a schematic sectional view showing what happens after [Fig. 11] when the hydraulic piston of the compressor according to the slow liquid-mechanical piston compressor-expander according to the invention has again come into contact with the start-of-stroke switch of the pump piston to force the latter to discharge the working liquid that it had sucked in [Fig. 10] towards the liquid spray nozzles via the pump discharge valve, the latter being shown enlarged in an inset.

[0113] [Fig. 13] is a schematic sectional view of a liquid spray pump of an expander formed by the slow liquid-mechanical piston compressor-expander according to the invention, the pump piston of which is set in motion in a pump cylinder by the hydraulic piston and by means of a setting spring, said pump piston being in the process of sucking working liquid via a pump inlet valve which the pump cylinder comprises, said valve being shown enlarged in a medallion.

[0114] [Fig. 14] is a schematic sectional view which shows what happens after [Fig. 13] when the pump piston has reached the end of its suction stroke while the hydraulic piston of the expander according to the slow liquid-mechanical piston compressor-expander according to the invention has continued its upward stroke by compressing the movement spring, and has not yet started its downward stroke.

[0115] [Fig. 15] is a schematic sectional view which shows what happens after [Fig. 14] when the hydraulic piston of the expander according to the slow liquid-mechanical piston compressor-expander according to the invention has started its downward stroke which has the effect of decompressing the movement spring, the pump piston remaining in contact with its upward stroke end stop.

[0116] [Fig. 16] is a schematic sectional view showing what happens after [Fig. 15] when the actuating spring has been relaxed to the point that the hydraulic piston of the expander according to the slow liquid-mechanical piston compressor-expander according to the invention has driven the pump piston in its movement and forced the latter to discharge the working liquid it had sucked in [Fig. 13] towards the liquid spray nozzles via the pump discharge valve, the latter being shown enlarged in an inset.

[0117] [Fig. 17] is a three-dimensional sectional view of an overflow pump and an overflow tank provided for a compressor formed by the slow liquid-mechanical piston compressor-expander according to the invention.

[0118] [Fig. 18] is a schematic sectional view of an overflow pump for a compressor formed by the slow liquid-mechanical piston compressor-expander according to the invention, the pressure prevailing in the overflow tank of said pump being higher than the pressure prevailing in the liquid cylinder, which has the effect of filling the variable volume of the overflow pump with working liquid coming from said overflow tank.

[0119] [Fig. 19] is a schematic sectional view showing what happens after [Fig. 18] when the pressure in the overflow tank of the overflow pump of the compressor formed by the slow liquid-mechanical piston compressor-expander according to the invention becomes substantially equal to the pressure in the liquid cylinder, which allows the two-body piston return spring to move the overflow pump piston to expel the working liquid previously admitted into the variable volume of the overflow pump towards the liquid cylinder.

[0120] [Fig.20] is a schematic sectional view of an overflow pump for a pressure reducer formed from the slow liquid-mechanical piston compressor-reducer according to the invention, the pressure prevailing in the overflow tank of said pump being lower than the pressure prevailing in the liquid cylinder which has the effect of filling the variable volume of the overflow pump with working liquid from said overflow tank.

[0121] [Fig.21] is a schematic sectional view showing what happens after the [Fig.20] when the pressure prevailing in the overflow tank of the overflow pump of the expander formed by the slow liquid-mechanical piston compressor-expander according to the invention becomes substantially equal to the pressure prevailing in the liquid cylinder, which allows the two-body piston return spring to move the overflow pump piston to expel the working liquid previously admitted into the variable volume of the overflow pump towards the liquid cylinder

[0122] [Fig.22] is a side view of a variant of the slow piston compressor-expander liquid-mechanical cylinder according to the invention according to which the liquid cylinder and the gas and liquid reservoir form a rigid assembly which pivots around a tilting axis consisting of a rolling track secured to the static frame on which a rolling surface secured to the gas and liquid reservoir can roll, the rolling track being linked to a rack which cooperates with a rolling surface toothed wheel linked to the rolling surface.

[0123] [Fig.23] is a side view of a variant of the slow piston compressor-expander liquid-mechanical apparatus according to the invention according to which counterbalancing means cooperate with the piston guide means to tilt, during rotation of the crank shaft, a rigid assembly formed of the liquid cylinder and the gas and liquid reservoir, said counterbalancing means consisting of a counterbalancing mast whose counterbalancing mass forms an unbalance opposite to that of said assembly.

[0124] DESCRIPTION OF THE INVENTION:

[0125] Figures 1 to 23 show the slow liquid-mechanical piston compressor-expander 1 according to the invention, various details of its components, its variants, and its accessories.

[0126] As can be seen particularly in figures 1 to 3, in [Fig.8], and in figures 10 to 16, the slow liquid-mechanical piston compressor-expander 1 defines a pneumatic variable volume 2 which forms a compressor 3 or an expander 4, a working gas 5 being able to enter said volume 2 via an inlet port 6 or leave said volume 2 via an outlet port 7.

[0127] Figures 1 to 4, 6 to 8, 10 to 16, and 22 and 23 show that the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises a liquid cylinder 8 which can, directly or indirectly, pivot around a tilting axis 9 which is perpendicular to the axis of said cylinder 8 and which is integral with a static frame 40, said axis 9 being able, according to the pivoting mechanism of said cylinder 8 provided, to move relative to said frame 40 as a function of the inclination of the liquid cylinder 8, the latter which can advantageously receive a thermal insulation layer 59 to prevent it from exchanging heat with the ambient environment.

[0128] It is noted that the tilting axis 9 can receive at least one roller bearing 105 as particularly shown in [Fig.4] and in figures 6 to 8, or at least one ball or needle bearing known per se, while the static frame 40 can for example be fixed or placed on the floor of a residential, commercial or industrial building 121.

[0129] As seen in figures 1 to 4, in [Fig.8] and in figures 10 to 16, the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises a hydraulic piston 10 which can translate in a sealed manner in the liquid cylinder 8 to form with the latter a hydraulic variable volume 12 which is completely or partly filled with a working liquid 13.

[0130] It is noted that the maximum acceleration or deceleration to which the hydraulic piston 10 is subjected between its mid-stroke and its top dead center must preferably remain lower than terrestrial gravity, so that the working liquid 13 always remains fully in contact with said piston 10 and that no phenomenon of cavitation or excessive mixing between the working gas 5 and the working liquid 13 occurs.

[0131] It is noted in figures 1 to 3, in [Fig.8] and in figures 10 to 16, that the hydraulic piston 10 can advantageously comprise at least one seal 51 whether the latter is toric, lip, composite, or of a type known to those skilled in the art, said seal 51 preventing the working liquid 13 from leaking between said piston 10 and the liquid cylinder 8.

[0132] Alternatively, to said seal 51, at least one cut or continuous metal segment can form a seal between the hydraulic piston 10 and the liquid cylinder 8, while the working liquid 13 can for example consist of pure water, or with glycol added to lower the solidification temperature of said water.

[0133] In Figures 1 to 3, in [Fig.8] and in Figures 10 to 16, it has also been shown that the slow liquid-mechanical piston compressor-expander 1 according to the invention also comprises a gas and liquid reservoir 14 which is connected to the hydraulic variable volume 12 by a communication conduit 15, so that said reservoir 14 fills mainly or completely with working liquid 13 when the hydraulic variable volume 12 is minimal, and fills partially or completely with working gas 5 when the hydraulic variable volume 12 is maximal, the absolute volume variation of the working gas 5 contained in the pneumatic variable volume 2 forming on the one hand, the pneumatic variable volume 2, and being on the other hand, approximately equal to the absolute volume variation of the working liquid 13 contained in the hydraulic variable volume 12 according to the principle of communicating vessels.

[0134] It is noted that the gas and liquid reservoir 14 can advantageously receive external thermal insulation to prevent it from exchanging heat with the ambient environment.

[0135] Figures 1 to 4, and Figures 8 to 16 show that the slow liquid-mechanical piston compressor-expander 1 according to the invention also comprises heat exchange and accumulation means 16 housed in the gas and liquid tank 14, said means 16 being able, on the one hand, to exchange heat with the working gas 5 or with the working liquid 13 and, on the other hand, to temporarily store all or part of said heat.

[0136] In the same said figures 1 to 4 and 8 to 16, it has been shown that the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises heat export or supply means 17 which take or which directly or indirectly transfer heat to the heat exchange and accumulation means 16 and / or to the working liquid 13 and / or to the working gas 5, said taken heat then being transferred to heating means 18 or said transferred heat having been previously taken to cooling means 19, said heating means 18 and said cooling means 19 being external to the gas and liquid tank 14 and being able to take the form of a heating-cooling floor 106 arranged in a commercial or residential building 121, a fan coil known per se, or an air-water exchanger 107, ground-water or water-water arranged outside 122, according to the principles usually adopted for aerothermal or geothermal heat pumps..

[0137] As seen in Figures 1 to 4 and in Figures 10 to 16, the slow liquid-mechanical piston compressor-expander 1 according to the invention also comprises filling means 20 which allow or prevent the passage of working gas 5 from an inlet plenum 21 to the gas and liquid reservoir 14 via the inlet port 6.

[0138] Figures 1 to 4 and Figures 10 to 16 also show that the slow liquid-mechanical piston compressor-expander 1 according to the invention also comprises draining means 22 which allow or prevent the passage of working gas 5 from the gas and liquid tank 14 to a discharge plenum 62 via the outlet port 7.

[0139] It can be seen in Figures 1 to 4, 6 to 8, 10 to 16, and in Figures 22 and 23, that the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises a connecting rod 11, a first rod end 29 of which is fixedly secured to the hydraulic piston 10, said rod 11 being approximately parallel to the longitudinal axis of said piston 10.

[0140] As can be clearly seen in Figures 1 to 3, in [Fig.8], and in Figures 10 to 16, the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises piston guide means 23 which hold the hydraulic piston 10 and the connecting rod 11 parallel to said cylinder 8, regardless of the position of said piston 10 in said cylinder 8;

[0141] Figures 1 and 2, Figures 6 to 9 and Figures 22 and 23 also show that the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises a crank shaft 24 or eccentric shaft known per se which can rotate about an axis parallel to the tilting axis 9 in at least one shaft bearing 25, and which has at least one crank 26 around which a second rod end 30 of the connecting rod 11 is articulated.

[0142] In the same said figures, it is noted that advantageously, the crank shaft 24 can rotate in the shaft bearing 25 and / or the second rod end 30 can be articulated around the crank 26 by means of a roller bearing 105, ball bearing or needle bearing known per se.

[0143] In Figures 1, 2, 6, 22 and 23, it can also be seen that the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises at least one drive motor 27 which directly or indirectly drives the crank shaft 24 in rotation, said motor 27 being able to be electric, thermal with internal or external combustion, hydraulic, pneumatic, or of any type known to those skilled in the art.

[0144] Finally and as shown in figures 1, 2, 6, 7, 8, 22 and 23 that the slow liquid-mechanical piston compressor-expander 1 according to the invention also comprises kinetic energy storage means 28 which are directly or indirectly connected to the crank shaft 24.

[0145] It has been shown in [Fig.l] that according to a variant of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the tilting axis 9 can be a tubular ball joint 111 which terminates the liquid cylinder 8 and the interior of which forms in whole or in part the communication conduit 15, said ball joint 111 being able to pivot in a sealed manner in a female ball joint housing 123 secured to the gas and liquid reservoir 14.

[0146] It will also be noted that this configuration is reversible, that is to say that the tubular ball joint 111 can terminate the gas and liquid reservoir 14 while the female ball joint housing 123 can be integral with the liquid cylinder 8.

[0147] It is also noted that the internal diameter of the liquid cylinder 8 can advantageously be provided to be less than or equal to the external diameter of the tubular ball joint 111 which forms a seal with the female ball joint housing 123, which prevents the pressure which prevails in said liquid cylinder 8 and in the gas and liquid reservoir 14 from exerting a force on said liquid cylinder 8 which would tend to move the latter away from the gas and liquid reservoir 14.

[0148] It is also noted in [Fig.l] that the female ball joint housing 123 can receive, at the equator of the tubular ball joint 111, a sealing joint 51 made of an abrasion-resistant material such as polytetrafluoroethylene loaded with anti-friction particles.

[0149] As can still be seen in [Fig.l], the female ball joint housing 123 can receive a circular cut pad 127 made of an anti-friction material such as bronze or “Teflon” whose mounting around the tubular ball joint 111 is permitted by a cut that said pad 127 has.

[0150] According to the variant of the slow liquid-mechanical piston compressor-expander 1 according to the invention shown in [Fig.l], the tubular ball joint 111 can receive in its center a ball joint axis 124 which is parallel to the tilting axis 9, said axis 124 being articulated around a ball joint hanger 125 which is directly or indirectly secured to the gas and liquid reservoir 14, the center of the ball joint axis 124 and the center of the tilting axis 9 being the same.

[0151] It will be noted that the ball joint hanger 125 keeps the distance between the liquid cylinder 8 and the gas and liquid reservoir 14 constant, said hanger 125 cooperating with the circular cut pad 127 which holds the tubular ball joint 111 in the center of the female ball joint housing 123.

[0152] It will also be noted that the ball joint axis 124 and its anchoring in the tubular ball joint 111 must preferably be compact and have a hydrodynamic shape which promotes low resistance to the passage of the working liquid 13 which circulates between the liquid cylinder 8 and the gas and liquid reservoir 14.

[0153] It will also be noted that the ball joint axis 124 may be a simple pivot connection or a cardan or spherical ball joint connection.

[0154] Still according to the variant embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention shown in [Fig.l], the ball joint hanger 125 can be connected to the gas and liquid tank 14 by means of an articulated hanger connection 126 around which said hanger 125 can rotate.

[0155] Figures 1, 2, 6, 7, 8 and Figures 10 to 16 show that according to another alternative embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the liquid cylinder 8 and the gas and liquid reservoir 14 can form a rigid assembly 31 which pivots around the tilting axis 9, the communication conduit 15 in this case being constituted by the junction zone between said cylinder 8 and said reservoir 14, and not necessarily having the same diameter as the latter.

[0156] It is noted that according to said variant, flexible conduits can advantageously connect the intake plenum 21 and / or the discharge plenum 62 for example to a high-pressure gas reservoir 58 or to a low-pressure gas reservoir 60, or can connect the gas and liquid reservoir 14 to heating means 18 and / or to cooling means 19.

[0157] As shown in Figures 10 to 16, the heat exchange and accumulation means 16 may consist of a porous medium 32 which has porosities 33 into which the working liquid 13 and the working gas 5 enter and exit alternately.

[0158] For example, said porous media 32 may be made of porous ceramic, a ceramic or metal structure, or a metal straw made of copper or aluminum.

[0159] Figures 10 to 16 also illustrate that the heat export or supply means 17 may consist of a circulating portion of the working liquid 13, said portion leaving the liquid cylinder 8 or the gas and liquid reservoir 14 via a liquid outlet conduit 34 to return to said cylinder 8 or to said reservoir 14 via a liquid inlet conduit 35, this after having given up heat to the heating means 18 or after having taken heat from the cooling means 19.

[0160] It is noted that in this case, circulation solenoid valves not shown can regulate the flow rate of working liquid 13 which passes into the liquid outlet conduit 34 and into the liquid inlet conduit 35.

[0161] As another alternative embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention, it has been shown in Figures 1 to 4, in Figures 8 and 9 and in [Fig. 17] that the heat export or supply means 17 can consist of at least one heat exchanger conduit 36 ​​housed in the gas and liquid tank 14 and in which circulates a heat transfer fluid 37 which transports the heat taken or transferred to the heat exchange and accumulation means 16 and / or to the working liquid 13 and / or to the working gas 5 to the cooling means 19 or to the heating means 18 via heat transport conduits 38.

[0162] It is noted that in this case, the heat exchange conduit 36 ​​can form in itself the heat exchange and accumulation means 16.

[0163] By way of example, the heat exchanger conduit 36 ​​may take the form of a winding of copper pipe 109 or aluminum, while the heat transport conduits 38 are coated with a thermal insulator on their portion between the gas and liquid reservoir 14 on the one hand, and the cooling means 19 or the heating means 18 on the other hand.

[0164] It is noted that the turns or layers that the heat exchanger conduit 36 ​​may constitute may be held in place in the gas and liquid reservoir 14 and relative to each other by holding plates or by separation baffles 110 which may constitute baffles and / or passage restrictions creating jets of working liquid 13 and / or working gas 5 during the passage of said liquid 13 and / or said gas 5 through said restrictions.

[0165] Furthermore, the heat exchanger conduit 36 ​​may receive external fins which increase its contact surface with the working liquid 13 or the working gas 5.

[0166] In Figures 1 to 4, in [Fig.8] and in Figures 10 to 16, it has been shown that, according to a particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the heat exchange and accumulation means 16 can consist of at least one liquid spray nozzle 71 supplied by a liquid spray pump 72, said nozzle 71 being able to atomize working liquid 13 into fine droplets in the internal volume of the gas and liquid reservoir 14, the number, position, and orientation of the nozzles 71 not being limited and being provided so that the working liquid 13 thus atomized exposes to the working gas 5 a large developed heat exchange surface, while the speed of entrainment of said gas 5 by said liquid 13 also favors as much as possible the heat exchanges between said gas 5 and said liquid 13.

[0167] It is noted that the liquid spray pump 72 may be of one or more pistons, gear, turbine or of a type known to those skilled in the art, and be housed inside or outside the gas and liquid reservoir 14.

[0168] The liquid spray pump 72 may for example consist of a piston which is directly or indirectly driven by a cam driven in rotation by the crank shaft 24, the profile of said cam being calculated so that the atomization of the working liquid 13 begins at the appropriate angular moment of rotation of said shaft 24, and for an optimal angular duration and according to an optimal intensity variation law.

[0169] It is noted that preferably, the liquid spray pump 72 draws working liquid 13 into the liquid cylinder 8 and / or into the gas and liquid reservoir 14 before discharging said liquid 13 via the liquid spray nozzle 71, so that the pressure difference between the inlet and the discharge of said pump 72 is minimal.

[0170] In [Fig. 22], it has been shown that according to another variant of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the tilting axis 9 can consist of a rolling track 41 which is integral with the static frame 40 and on which a rolling surface 42 can roll which is directly or indirectly integral with the liquid cylinder 8, a rolling track toothed wheel 43 or a rack whose pitch circle 44 coincides with the line of contact between the rolling track 41 and the rolling surface 42 being integral with the static frame 40 and cooperating with a rolling surface toothed wheel 45 or a rack which is directly or indirectly integral with the liquid cylinder 8.

[0171] This particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention makes it possible to limit friction losses at the level of the tilting axis 9 while synchronizing the angular positioning of the cylinder at liquid 8 compared to static frame 40.

[0172] It is noted that in this case, a retaining flange can be provided which is integral with the liquid cylinder 8 and which can come into contact with the static frame 40 if the pressure in said cylinder 8 is insufficient to keep the rolling track 41 in contact with the rolling surface 42.

[0173] It is noted that depending on the geometry chosen for the rolling surface 42 and for the rolling track 43, the tilting axis 9 of the liquid cylinder 8 can, while rotating, move relative to the static frame 40 according to an infinite number of kinematic laws.

[0174] As can be seen in Figures 1 to 3, in Figures 6 to 8, in Figures 10 to 16, and in Figures 22 and 23, the piston guide means 23 of the slow liquid-mechanical piston compressor-expander 1 according to the invention may consist of a sliding pivot connection 47 formed between an external cylindrical surface 48 that the connecting rod 11 has and a sliding ring 49 which is integrally connected to the liquid cylinder 8 by means of a ring-carrying structure 50 which may, according to a complementary variant embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention, constitute a lubricant reservoir which contains a lubricant, the latter having the task of lubricating the sliding ring 49 on the one hand, and one or more seals 51 that the hydraulic piston 10 may comprise at its periphery on the other hand.

[0175] It is noted that a lubricant sprinkler or injector may be provided which atomizes lubricant inside said lubricant reservoir to ensure good distribution of lubricant over all the organs which require lubrication.

[0176] It has been shown in figures 1 to 4, in [Fig.8], and in figures 10 to 16, that the piston guide means 23 can consist of a guide skirt 57 arranged on the periphery of the hydraulic piston 10, said skirt 57 being able to translate with little play in said cylinder 8 to center said piston 10 in said cylinder 8, whatever the axial position of said piston 10 in said cylinder 8.

[0177] It has also been shown in Figures 1 to 4 and in Figures 10 to 12 that the filling means 20 and / or the emptying means 22 may consist of at least one compressor valve 52 and / or at least one compressor pilot valve 53, while in operation, the working gas 5 is expelled from the gas and liquid reservoir 14 via the discharge plenum 62 under a pressure higher than that under which it was previously introduced into said reservoir 14 via the inlet plenum 21, while the heat export or supply means 17 transfer heat to the heating means 18, so that the pneumatic variable volume 2 forms a compressor 3.

[0178] It is noted that the heating means 18 may for example consist of a underfloor heating installed in a commercial or residential building 121, a fan coil known per se, or an air-water, air-ground or water-water exchanger installed outdoors 122, according to the principles usually adopted for aerothermal or geothermal heat pumps.

[0179] It is noted that the compressor valve 52 can be formed of a simple strip or contact part returned to a sealed seat by a spring of any type, or be formed of a valve assisted by an electromechanical actuator which cooperates with at least one pressure switch or with a pressure sensor coupled to a computer 120.

[0180] It has been shown in Figures 13 to 16 that the filling means 20 and / or the emptying means 22 may consist of at least one pilot-controlled pressure reducer valve 54, while in operation, the working gas 5 is expelled from the gas and liquid tank 14 via the discharge plenum 62 under a pressure lower than that under which it was previously introduced into said tank 14 via the inlet plenum 21, while the heat export or supply means 17 take heat from the cooling means 19, so that the pneumatic variable volume 2 forms a pressure reducer 4.

[0181] It is noted that the cooling means 19 may for example consist of a cooling floor fitted in a commercial or residential building 121, a fan coil known per se, or an air-water, air-ground or water-water exchanger fitted outside 122, according to the principles usually adopted for aerothermal or geothermal heat pumps.

[0182] According to a variant of the slow liquid-mechanical piston compressor-expander 1 according to the invention shown in Figures 6 to 9, the discharge plenum 62 of the compressor 3 can be connected to the inlet plenum 21 of the expander 4 by a high-pressure gas conduit 56 so that the working gas 5 discharged via the discharge plenum 62 of said compressor 3 is introduced into said expander 4 via the inlet plenum 21 of said expander 4, the crank shaft 24 of said compressor 3 being directly or indirectly connected to the crank shaft 24 of said expander 4, said compressor 3 and said expander 4 cooperating to form a heat pump 55 executing a heat pump cycle close to that of Carnot, that is to say a quasi-adiabatic compression followed by a quasi-isothermal compression carried out in the compressor 3, then a quasi-adiabatic expansion followed by quasi-isothermal expansion carried out in the expander 4.

[0183] According to this particular embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the crank shaft 24 of the compressor 3 and the crank shaft 24 of the expander 4 may form only one and the same crank shaft 24 comprising at least two cranks 26, one of which is for the compressor 3, and the other for the regulator 4.

[0184] Alternatively, the crank shaft 24 of the compressor 3 may be indirectly connected to the crank shaft 24 of the expander 4 via mechanical, electrical, hydraulic, pneumatic transmission means, or via any other transmission means whatsoever.

[0185] It is noted that advantageously, the angular position on the crank shaft 24 of the crank 26 of the compressor 3 relative to that of the crank 26 of the expander 4 can be calculated so that the resistive torque exerted by said compressor 3 on the crank shaft 24 is as much as possible compensated by the driving torque exerted by said expander 4 on said shaft 24, so that the drive motor 27 is subjected to the lowest possible maximum driving or resistive torque.

[0186] In [Fig.9], it has also been shown that the high-pressure gas conduit 56 can be connected to at least one high-pressure gas reservoir 58 which can accumulate hot, high-pressure working gas 5, the high-pressure gas conduit 56 and / or the high-pressure gas reservoir 58 being advantageously thermally insulated from their external environment by a thermal insulation layer 59.

[0187] Still in [Fig.9], it has been shown that the intake plenum 21 of the compressor 3 and the discharge plenum 62 of the expander 4 can communicate via a low-pressure gas reservoir 60 to which they are respectively connected by a low-pressure gas conduit 61, said low-pressure gas reservoir 60 being able to accumulate cold and relatively low-pressure working gas 5, the low-pressure gas conduit 61 and / or said reservoir 60 being able to advantageously be thermally exposed to the environment to which the cooling means 19 are themselves exposed, or even being able to form in whole or in part a low-pressure gas reheating exchanger 39 which forces said environment to give up heat to said working gas 5.

[0188] Thus and as shown in [Fig.9], a circulation turbine 46 can force the working gas 5 contained in the low-pressure gas tank 60 to circulate in a low-pressure gas reheating exchanger 39 that said tank 60 comprises, while at least one motor-fan 108 forces atmospheric air from the environment to which the cooling means 19 are exposed to pass through said exchanger 39.

[0189] Advantageously, the pressure prevailing in the low pressure tank 60 can be higher than atmospheric pressure to give the heat pump 55 greater compactness.

[0190] It is noted that advantageously, to the extent that the heat pump 55 which forms the slow liquid-mechanical piston compressor-expander 1 according to the invention comprises a low-pressure gas reservoir 60, the working gas 5 may be different from air at spherical and be made up of any element or molecule such as pure nitrogen, helium, argon, or carbon dioxide, said element or molecule being chosen according to its chemical reactivity, its thermodynamic performance, and its ability to promote heat exchanges, in particular with the working liquid 13 and the heat exchange and accumulation means 16.

[0191] This also makes it possible to prevent corrosion of the components constituting the slow liquid-mechanical piston compressor-expander 1 according to the invention, and the development of micro-organisms.

[0192] It is noted that, if they are thermally isolated from the external environment, the high-pressure gas reservoir 58 and the low-pressure gas reservoir 60 can form with the heat pump 55 a total closed volume which conserves the energy in the form of pressure and / or heat as long as said energy is not transformed into useful heat or cold, which contributes to the high efficiency of said pump 55.

[0193] It is noted in Figures 1 to 4, in Figures 6 to 8, in Figures and 10 to 16, and in Figures 22 and 23, that the inlet plenum 21 and the discharge plenum 62 can advantageously be positioned in the upper part of the gas and liquid tank 14, the latter itself being positioned above the liquid cylinder 8 so that due to the Earth's gravity, the working gas 5 always leaves the gas and liquid tank 14 as a priority via the discharge plenum 62, and that the working liquid 13 always enters said tank 14 as a priority via the inlet plenum, the working liquid 13 always remaining essentially below the working gas 5 in the rigid assembly 31, even if said liquid 13 may contain a certain proportion of said gas 5 dissolved or in the form of bubbles.

[0194] According to a particular variant embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention shown in Figures 2 to 4, in Figures 6 to 8, and in Figures 10 to 16, the tilting axis 9 may consist of a hollow cylindrical axis 63 which has at least one emerging radial lumen 64, said cylindrical axis 63 being positioned above the gas and liquid reservoir 14, while the inlet plenum 21 and / or the discharge plenum 62 is connected to an annular gas collector 65 which surrounds said cylindrical axis 63 and which includes the emerging radial lumen 64 so that the working gas 5 can circulate between the interior of the hollow cylindrical axis 63 and the inlet plenum 21 and / or the discharge plenum 62 via the emerging radial lumen 64 and the annular gas collector 65.

[0195] It is noted that rotating shaft seals can advantageously be placed axially on either side of the emerging radial lumen 64 and at the interface between the hollow cylindrical axis 63 and the annular gas collector 65, said seals forming a seal against the working gas 5 between said axis 63 and said collector 65.

[0196] As a particular embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention detailed in [Fig. 6], the kinetic energy storage means 28 may consist of a low-speed flywheel 66 which is integral in rotation, on the one hand, with the crank shaft 24, and on the other hand, with a toothed crown 67 which the drive motor 27 drives in rotation by means of at least one crown drive pinion 68 whose primitive diameter is smaller than that of said crown 67, the latter and said pinion 68 forming a high-reduction gear system 69, while a high-speed flywheel 70 is directly or indirectly integral in rotation with the crown drive pinion 68.

[0197] According to this particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the variations in instantaneous torque imposed on the crank shaft 24 by the compression or expansion of the working gas 5 in the gas and liquid reservoir 14 are mainly absorbed by the inertia of the low-speed flywheel 66 and by that of the high-speed flywheel 70, so that the torque which resists or drives the drive motor 27 is smoothed out, said motor 27 then being mainly subjected to the sole average resisting torque necessary to maintain regular rotation of the crank shaft 24.

[0198] It will be noted that the high speed flywheel 70 may optionally be enclosed in a vacuum housing.

[0199] In this case, the transmission of power between said flywheel 70 and the crown drive pinion 68 can be carried out by contactless magnetic coupling.

[0200] It will also be noted that to facilitate the rotation of the assembly consisting of the low-speed flywheel 66 and the crank shaft 24, the drive motor 27 can be fixedly secured in rotation to the high-speed flywheel 70, while a disengageable coupler can be inserted between the assembly formed by said motor 27 and said flywheel 70 on the one hand, and the crown drive pinion 68 on the other hand, said coupler being able to be magnetic, hydraulic, or of any other type.

[0201] It has been shown in figures 1, 2, 6, 9, 22 and 23 that a high gear reduction system 69 can advantageously be inserted between the drive motor 27 and the crown drive pinion 68.

[0202] As shown in Figures 3 and 4, and in Figures 10 to 16, the liquid spray pump 72 may consist of a pump cylinder 73 which is arranged in the liquid cylinder 8 and / or in the extension of said cylinder 8, a pump piston 74 set in motion by the hydraulic piston 10 and / or by the liquid cylinder 8 being able to translate in said pump cylinder 73.

[0203] It is noted that the pump cylinder 73 can be directly or indirectly integral, either, with the liquid cylinder 8 or the gas and liquid tank 14, or with the hydraulic piston 10, while the same applies to the pump piston 74.

[0204] It is noted, particularly in figures 10 to 16, that by way of non-limiting example, the liquid spray pump 72 may comprise at least one pump inlet valve 79 and at least one pump discharge valve 80, said valves 79, 80 being able to be integral either with the pump cylinder 73 or with the pump piston 74.

[0205] It may also be noted that the pump cylinder 73 may include discharge orifices along its length, said orifices making it possible to increase or decrease the discharge pressure of the working liquid 13 by the liquid spray pump 72 depending on the relative position of the pump piston 74 in said pump cylinder 73.

[0206] In Figures 10 to 12, it is noted that the pump piston 74 may include a start-of-stroke button 77 by means of which it is set in motion, said piston 74 being returned to an end-of-stroke stop 78 by a piston return mass 76 or a piston return spring not shown.

[0207] This particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention allows in particular that the stroke of the pump piston 74 is shorter than that of the hydraulic piston 10 and that, for example, the liquid spray nozzle 71 atomizes working liquid 13 in the internal volume of the gas and liquid reservoir 14 only when the hydraulic piston 10 reaches the vicinity of its top dead center.

[0208] In Figures 13 to 16, it has been shown that the pump piston 74 can be set in motion by means of a setting spring 81 which makes it possible to decouple the variation in distance between the pump piston 74 and the pump cylinder 73 from that between the liquid cylinder 8 and the hydraulic piston 10.

[0209] This particular configuration can also be retained to maintain a relatively constant pressure in the pump cylinder 73 regardless of the rotation speed of the crank shaft 24.

[0210] In Figures 3, 6 and 7, and in Figures 17 to 21, it has been shown that with each revolution of the crank shaft 24, an overflow pump 82 can transfer a small quantity of working liquid 13 from an overflow tank 83 to the gas and liquid reservoir 14 and / or the liquid cylinder 8.

[0211] Thus, when the hydraulic piston 10 makes back-and-forth movements in the liquid cylinder 8 and when the hydraulic variable volume 12 is minimal, the gas and liquid reservoir 14 is completely filled with working liquid 13, the small quantity of working liquid 13 introduced by the overflow pump 82 into the gas and liquid reservoir 14 overflowing with each turn of the crank shaft 24 of said tank 14 to return to overflow tank 83 via outlet port 7 and discharge plenum 62.

[0212] This particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention allows all of the working gas 5 contained in the pneumatic variable volume 2 to be expelled from said volume 2 when the hydraulic variable volume 12 is minimal, which gives said volume 2 an infinite volumetric ratio, and a volumetric efficiency close to one hundred percent.

[0213] As noted in [Fig.3], the overflow tank 83 can communicate with the discharge plenum 62, the working gas pressure 5 which prevails in said tank 83 being close to or identical to that which prevails in said plenum 62 while said tank 83 is located below the discharge plenum 62 so that, due to the Earth's gravity, the working liquid 13 which overflows from the gas and liquid tank 14 via the outlet port 7 and the discharge plenum 62 naturally returns to said overflow tank 83.

[0214] It is noted in Figures 17 to 21 that the overflow pump 82 comprises a blind pump cylinder 84 in which an overflow pump piston 85 can translate in a sealed manner, the latter and said cylinder 84 forming a variable overflow pump volume 86 which, when it increases, fills with working liquid 13 from the overflow tank 83 via at least one overflow pump inlet valve 87 and which, when it decreases, discharges said liquid 13 towards the gas and liquid tank 14 and / or the liquid cylinder 8 via a discharge valve 88.

[0215] It is noted that the blind pump cylinder 84 can be assembled or not, that is to say that it can be made from a single piece, or receive a cylinder head which closes the end opposite to that closed by the overflow pump piston 85.

[0216] In Figures 17 to 19, it is noted that the overflow pump piston 85 may be a two-body stepped piston 89 which comprises a large-diameter body 93 which has a large-section face 90 which forms one of the walls of the variable overflow pump volume 86, said stepped piston 89 also comprising, axially opposite the large-section face 90, a small-diameter body 94 which can translate in a sealed manner in an actuating cylinder 92 whose internal volume is connected directly or indirectly to that of the liquid cylinder 8, said small-diameter body 94 having a small-section face 91 on which the pressure prevailing in the liquid cylinder 8 is exerted, said stepped piston 89 also offering, at the junction between the large-diameter body 93 and the small-diameter body 94, a medium-section face 95 from which emerges the small-diameter body 94, which is connected to the overflow tank 83,and which is subjected to the pressure prevailing in said reservoir 83, while a stepped piston stop 117 fixes the maximum volume of the, variable volume overflow pump 86 and that a two-body piston return spring 96 tends to push the two-body stepped piston 89 towards its large section face 90.

[0217] In Figures 17 to 19, it is also noted that the discharge valve 88 comprises a valve actuator piston 97 which can translate in a sealed manner in a valve actuator cylinder 98 and which has, firstly, an axial valve actuator face 99 which communicates with the overflow tank 83 and on which the pressure prevailing in said tank 83 is exerted, said face 99 being able to lift an overflow valve 100 from an overflow valve seat 104 when the valve actuator piston 97 moves towards said face 99 which has the effect of putting the variable volume of the overflow pump 86 into communication with the gas and liquid tank 14 and / or the liquid cylinder 8 via said overflow valve 100, and secondly, an axial face on the liquid cylinder side 102 which communicates with the liquid cylinder 8 or with the tank gas and liquid 14, on which the pressure prevailing in said cylinder 8 is exerted,and which can come into contact with a liquid cylinder-side stop 118 when the valve actuator piston 97 moves towards said liquid cylinder-side axial face 102, while an actuating piston return spring 103 tends to push the valve actuator piston 97 back towards its valve actuating axial face 99, and an overflow valve return spring 128 tends to bring the overflow valve 100 back into contact with the overflow valve seat 104 with which it cooperates, the force produced by the actuating piston return spring 103 being greater than the force produced by the overflow valve return spring 128. ,

[0218] As an alternative not shown, the discharge valve 88 may comprise a cylindrical slide valve on the external surface of which a slide valve groove is arranged, said slide valve being able to translate in a sealed manner in a slide valve cylinder into which open an inlet port connected to the variable volume of the overflow pump 86, and an exhaust port connected to the gas and liquid reservoir 14 or to the liquid cylinder 8, while depending on the axial position of the cylindrical slide valve in the slide valve cylinder, the slide valve groove may or may not connect the inlet port with the exhaust port, the cylindrical slide valve 97 having an axial face on the reservoir side which communicates with the overflow reservoir 83 and on which the pressure prevailing in said reservoir 83 is exerted, and an axial face on the liquid cylinder side which may rest on a slide valve stop on the liquid cylinder side, which communicates with the liquid cylinder 8,or with the gas and liquid reservoir 14 and on which the pressure prevailing in said cylinder 8 or that prevailing in the gas and liquid reservoir 14 is exerted, while a drawer return spring tends to push the cylindrical drawer towards its axial face on the reservoir side up to a , reservoir-side drawer stop which, when reached by said drawer, connects the intake port with the exhaust port via the drawer groove.

[0219] In Figures 20 and 21, it has been shown that the overflow pump piston 85 may be a two-body stepped piston 89 which comprises a large-diameter body 93 which has a large-section face 90 which is connected to the overflow reservoir 83 and which is subjected to the pressure prevailing in said reservoir 83, said stepped piston 89 also comprising, axially opposite the large-section face 90, a small-diameter body 94 which can translate in a sealed manner in an actuating cylinder 92 whose internal volume is connected directly or indirectly to that of the liquid cylinder 8, said small-diameter body 94 having a small-section face 91 on which the pressure prevailing in the liquid cylinder 8 is exerted, said stepped piston 89 also offering, at the junction between the large-diameter body 93 and the small-diameter body 94,a medium-section face 95 from which emerges the small-diameter body 94, said face 95 forming one of the walls of the variable volume of the overflow pump 86, while a stepped piston stop 117 fixes the maximum volume of the variable volume of the overflow pump 86 and a two-body piston return spring 96 tends to push the two-body stepped piston 89 towards its small-section face 91.,

[0220] Still in Figures 20 and 21, it has been shown that the discharge valve 88 may comprise a valve actuator piston 97 which can translate in a sealed manner in a valve actuator cylinder 98 and which has, firstly, an axial valve actuator face 99 which communicates with the liquid cylinder 8 and on which the pressure prevailing in said cylinder 8 is exerted, said face 99 being able to lift an overflow valve 100 from an overflow valve seat 104 when the valve actuator piston 97 moves towards said face 99 which has the effect of putting the variable volume of the overflow pump 86 into communication with the gas and liquid reservoir 14 and / or the liquid cylinder 8 via said overflow valve 100, and secondly, a reservoir-side axial face 101 which communicates with the overflow reservoir 83, on which the pressure prevailing in said reservoir 83 is exerted,and which can come into contact with an overflow tank-side stop 130 when the valve actuator piston 97 moves towards said tank-side axial face 101, while an actuating piston return spring 103 tends to push the valve actuator piston 97 back towards its valve actuating axial face 99, and an overflow valve return spring 128 tends to bring the overflow valve 100 back into contact with the overflow valve seat 104 with which it cooperates, the force produced by the actuating piston return spring 103 being greater than the force produced by the overflow valve return spring 128. ,

[0221] As an alternative not shown, the discharge valve 88 may comprise a cylindrical slide valve on the external surface of which a slide valve groove is arranged, said slide valve being able to translate in a slide valve cylinder into which an inlet port connected to the variable volume of the overflow pump 86 and an exhaust port connected to the gas and liquid reservoir 14 or to the liquid cylinder 8 open, while depending on the axial position of the cylindrical slide valve in the slide valve cylinder, the slide valve groove may or may not connect the inlet port with the exhaust port, the cylindrical slide valve having an axial face on the reservoir side which may rest on a slide valve stop on the reservoir side, which communicates with the overflow reservoir 83, and on which the pressure prevailing in said reservoir 83 is exerted,and an axial face on the liquid cylinder side which communicates with the liquid cylinder 8 or with the gas and liquid reservoir 14 and on which the pressure prevailing in said cylinder 8 is exerted, while a slide return spring tends to push the cylindrical slide in the direction of its axial face on the liquid cylinder side up to a slide stop on the liquid cylinder side which, when reached by said slide, puts the intake port into communication with the exhaust port via the slide groove.

[0222] According to a particular embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention shown in [Fig.23], counterbalancing means 112 can replace in whole or in part the piston guide means 23 to tilt the liquid cylinder 8 during the rotation of the crank shaft 24 so as to reduce or even cancel the radial forces exerted on said guide means 23 by the tilting of said cylinder 8 due to the mass of the latter, and the Earth's gravity.

[0223] According to this particular configuration, the counterbalancing means 112 may consist of a counterbalancing mast 113 which, on the one hand, comprises a counterbalancing mass 116 and which, on the other hand, is articulated around a mast axis 114 which is parallel to the tilting axis 9 of the liquid cylinder 8 and which is integral with the static frame 40, while the counterbalancing mast 113 forms with said cylinder 8 a pivoting-sliding articulation 115 and constitutes an unbalance opposite to that of said cylinder 8, the pivoting-sliding articulation 115 being able to consist, as shown in [Fig.23], of an axis which emerges from the external surface of the liquid cylinder 8, said axis receiving a bearing which can move in an oblong recess which the counterbalancing mast 113 presents.

[0224] It is noted that according to a particular embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the counterbalancing mast 113 can receive a counterbalancing mass 116 whose weight and / or position can be variable.

[0225] It is noted that as an alternative to the above, the counterbalancing means 112 may consist of a mechanism for driving and synchronizing the rotation of the liquid cylinder 8 of any type whatsoever, or of mechanisms with elastic connections which also tend to reduce or even cancel out the radial forces exerted on the piston guide means 23 by the inclination of the cylinder 8 due to the mass of the latter, and the Earth's gravity.

[0226] OPERATION OF THE INVENTION:

[0227] The operation of the slow liquid-mechanical piston compressor-expander 1 according to the invention is easily understood from Figures 1 to 23.

[0228] The objective of said compressor-expander 1 is in particular to constitute a pneumatic variable volume 2 in which the heat exchanges are maximized between a working gas 5, which may be atmospheric air, and a working liquid 13, which may be water, during the compression or expansion of said gas 5 and this, so that said compression or said expansion is as isothermal as possible, the working liquid 13 which has a high volumetric heat capacity mainly imposing its temperature on the working gas 5 whose volumetric heat capacity is low.

[0229] Thus, when, as shown in Figures 1 to 4, Figures 10 to 12, and Figures 22 and 23, the slow liquid-mechanical piston compressor-expander 1 according to the invention forms a compressor 3, a working gas 5 is compressed in the pneumatic variable volume 2.

[0230] In this case, said gas 5 first increases in pressure and temperature until the latter reaches that of the working liquid 13 contained in the liquid cylinder 8 and in the gas and liquid reservoir 14, then, this temperature plateau being reached, said gas 5 continues to be compressed and to increase in pressure while the heat produced by the compression of said gas 5 is transferred to said liquid 13 as said heat is produced, to the point that the compression of said gas 5 is completed in a near-isothermal manner.

[0231] If, conversely and as shown in Figures 13 to 16, the slow liquid-mechanical piston compressor-expander 1 according to the invention forms an expander 4, a working gas 5 is expanded in the pneumatic variable volume 2.

[0232] In this other case, said gas 5 first drops in pressure and temperature until the latter reaches that of the working liquid 13 contained in the liquid cylinder 8 and in the gas and liquid reservoir 14, then, this temperature plateau having been reached, said gas 5 continues to be expanded and to drop in pressure while its temperature is permanently maintained close to that of the working liquid 13, the latter thereby giving up heat to said gas 5, to the point that the expansion of said gas 5 ends in a near-isothermal manner.

[0233] Thus and as shown in figures 1 to 4, in figures 10 to 12, in figures 22 and 23, and in figures 13 to 16, the following slow liquid-mechanical piston compressor-expander 1 the invention may form a compressor 3, or an expander 4, the gas and liquid reservoir 14 in which the pneumatic variable volume 2 is formed housing heat exchange and accumulation means 16 provided to exchange heat with the working gas 5 or with the working liquid 13, and to temporarily store all or part of said heat before exporting the latter via heat export or supply means 17 to heating means 18 as shown in [Fig.9], or after having imported said heat via said export or supply means 17 from cooling means 19 as also shown in [Fig.9].

[0234] As shown in [Fig.9] and by way of non-limiting example, the heating means 18 may consist of a heating-cooling floor 106 installed in a building 121, while the cooling means 19 may take the form of an air-water exchanger 107 placed outside 122 of said building 121.

[0235] In addition to promoting heat exchanges between a working gas 5 and a working liquid 13 during the compression or expansion of said gas 5, the slow liquid-mechanical piston compressor-expander 1 according to the invention minimizes energy losses through friction, the latter being undesirable in that they reduce the efficiency of the compressor 3 or the expander 4 formed by said compressor-expander 1.

[0236] For this, unlike conventional connecting rod and crank systems that comprise compressors and reciprocating thermal engines commonly sold, the hydraulic piston 10 of the slow liquid-mechanical piston compressor-expander 1 according to the invention translates in a sealed manner in the liquid cylinder 8 to form with the latter a hydraulic variable volume 12, this without undergoing significantly high radial force.

[0237] As can be seen for example in figures 1 and 2, this result is obtained by pivoting the liquid cylinder 8 around a tilting axis 9 which is perpendicular to the axis of said cylinder 8 and which is integral with a static frame 40, while the hydraulic piston 10 and its connecting rod 11 are kept parallel to the liquid cylinder 8 by piston guide means 23 integral with said cylinder 8, whatever the position of said piston 10 in said cylinder 8.

[0238] As seen in Figures 1 to 3, in Figures 6 to 8, in Figures 10 to 16, and in Figures 22 and 23, the piston guide means 23 may consist of a sliding pivot connection 47 formed between an external cylindrical surface 48 that the connecting rod 11 has and a sliding ring 49 which is integrally connected to the liquid cylinder 8 by means of a ring-carrying structure 50.

[0239] Thus and as shown in Figures 1 and 2, Figures 6 to 8, and Figures 22 and 23, the crank 26 around which a second rod end 30 of the connecting rod 11 is articulated always remains approximately in the axis of the liquid cylinder 8.

[0240] According to this particular configuration specific to the slow piston compressor-expander liquid-mechanical system 1 according to the invention, unlike the most widespread connecting rod and crank systems, the axial force exerted by the pressure of the working gas 5 on the hydraulic piston 10 via the working liquid 13 no longer results in any radial force whatsoever exerted by said piston 10 on the liquid cylinder 8.

[0241] Because in fact, the low rotation speed of the slow liquid-mechanical piston compressor-expander 1 does not favor the establishment of a hydrodynamic lubrication regime between the hydraulic piston 10 and the liquid cylinder 8, said regime requiring, in order to be established, a high relative speed between said piston 10 and said cylinder 8.

[0242] Furthermore, if the working liquid which enters between the hydraulic piston 10 and the liquid cylinder 8 is water, the latter being of low viscosity and having weak lubricating properties, it is also unfavorable to the establishment of a hydrodynamic lift regime at the interface between said piston 10 and said cylinder 8.

[0243] This particular characteristic of the slow liquid-mechanical piston compressor-expander 1, which consists of eliminating any radial force exerted by the hydraulic piston 10 on the liquid cylinder 8, is of prime importance, in particular to give any heat pump 55 formed from a compressor 3 and an expander 4 according to the invention a high efficiency and a coefficient of performance higher than that of conventional heat pumps operating on a refrigerant fluid.

[0244] Still with the objective of minimizing energy losses through friction, it can be seen in figures 1 to 3, in figures 6 to 8, and in figures 22 and 23, that all the pivot connections of the slow liquid-mechanical piston compressor-expander 1 receive a roller bearing 105 known per se, whether it is the tilting axis 9, the shaft bearings 25, or the crank 26.

[0245] The effective coefficient of friction of the roller bearings 105 being very low, said pivot connections dissipate little energy and have little negative impact on the energy efficiency of any heat pump 55 made from the slow liquid-mechanical piston compressor-expander 1 according to the invention.

[0246] The objective of the slow liquid-mechanical piston compressor-expander 1 according to the invention is also to minimize energy losses due to leaks of working gas 5, said leaks reducing the effective efficiency of the compressor 3 or the expander 4 formed by said compressor-expander 1.

[0247] In this respect, it is noted that the hydraulic piston 10 forms a seal with the liquid cylinder 8 in which it translates, and that this seal applies to the working liquid 13 and not to the working gas 5 itself which, due to its low density, the Earth's gravity, and the low rotation speed of the slow liquid-mechanical piston compressor-expander 1, always remains above said working liquid 13.

[0248] It results from this particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention that the seal that the hydraulic piston 10 forms with the liquid cylinder 8 only prevents possible leaks of working liquid 13 and not of working gas 5, the volume flow rate of said possible leaks being strongly limited by the high density and viscosity of said liquid 13, in this case and by way of non-limiting example, water.

[0249] It is also noted that a high level of sealing between the hydraulic piston 10 and the liquid cylinder 8 is all the more achievable as the slow liquid-mechanical piston compressor-expander 1 rotates slowly.

[0250] Indeed, the low rotation speed of said compressor-expander 1 implies a low relative linear speed between the hydraulic piston 10 and the liquid cylinder 8, which makes it possible to equip the hydraulic piston 10 with a flexible and continuous seal 51, for example consisting of an elastomer O-ring which presses against the internal wall of the liquid cylinder 8 a friction ring made of polytetrafluoroethylene loaded with anti-friction particles, this material being notoriously resistant to abrasion.

[0251] It is noted that advantageously, the working liquid 13 can be formed from a mixture of glycol and water which, in addition to lowering the solidification temperature of said water and preventing it from freezing, can contribute to increasing the durability of the seal 51, to limiting the energy losses by friction produced by said seal 51, and to further reducing, if necessary, any leaks of working liquid 13 at the interface of the contact between the hydraulic piston 10 and the liquid cylinder 8.

[0252] It will be noted that, so that the working liquid 13 always remains fully in contact with the hydraulic piston 10 and so that no cavitation or overmixing phenomenon occurs between the working gas 5 and the working liquid 13, the maximum acceleration or deceleration of the hydraulic piston 10 between its mid-stroke and its top dead center must remain lower than Earth's gravity.

[0253] As such, the rotation speed of the crank shaft 24 must remain low, which we will set, as a non-limiting example, at forty revolutions per minute.

[0254] This low speed explains the need to add to the crank shaft 24 kinetic energy storage means 28 which are, according to the embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention shown in Figures 1 and 2, in Figures 6 to 8, and in Figures 22 and 23, constituted by a low-speed flywheel 66 which is integral in rotation, on the one hand, with the crank shaft 24, and on the other hand, with a toothed crown 67 which the drive motor 27 drives in rotation by means of a high-efficiency crown drive pinion 68 whose primitive diameter is smaller than that of said crown 67, the latter and said pinion 68 forming a high-reduction gear system 69.

[0255] It is also noted in [Fig.6] that a high-speed flywheel 70 can advantageously be provided integral in rotation with the crown drive pinion 68.

[0256] According to this particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the variations in instantaneous torque imposed on the crank shaft 24 by the compression or expansion of the working gas 5 in the gas and liquid reservoir 14 are mainly absorbed by the inertia of the low-speed flywheel 66 and by that of the high-speed flywheel 70, so that the torque which resists or drives the drive motor 27 is smoothed out, said motor 27 then being mainly subjected to the average resisting torque necessary to maintain regular rotation of the crank shaft 24.

[0257] In addition to avoiding any phenomenon of cavitation or overmixing between the working gas 5 and the working liquid 13, the low rotation speed of forty revolutions per minute imposed on the crank shaft 24 leaves a significant amount of time for the transfer of the working gas 5 to the filling means 20 or the emptying means 22 of the compressor 3 and the expander 4.

[0258] Indeed, in addition to the time allowed for heat exchanges to occur in the gas and liquid reservoir 14 between the working gas 5 and / or the working liquid 13 on the one hand, and the heat exchange and accumulation means 16 on the other hand, the advantage of a slow rotation of the compressor 3 or the expander 4 is that it allows time for the transfer of the working gas 5 to take place, so as to limit pressure losses at the inlet port 6 and the outlet port 7 of said compressor 3 or said expander 4.

[0259] Because in fact, the filling means 20 which allow or which prevent the passage of the working gas 5 from an inlet plenum 21 to the gas and liquid tank 14 via the inlet port 6, or the emptying means 22 which allow or prevent the passage of working gas 5 from the gas and liquid tank 14 to a discharge plenum 62 via the outlet port 7, can consist of at least one compressor valve 52 assisted or not by electrical means, at least one controlled compressor valve 53, or at least one controlled expansion valve 54.

[0260] However, these components 52, 53, 54 oppose to their setting into motion inertial forces whose intensity evolves to the square of the speed of rotation of the crank shaft 24 and as such, if said shaft 24 only rotates for example at forty revolutions per minute, said forces are so weak that they no longer have a negative consequence on the efficiency of the slow liquid-mechanical piston compressor-expander 1 according to the invention.

[0261] It follows from the above that the pressure-volume thermodynamic diagram effective of a heat pump 55 comprising a compressor 3 and an expander 4 formed from the slow liquid-mechanical piston compressor-expander 1 according to the invention, is close to that of the ideal Carnot cycle, the practice joining the theory as closely as possible.

[0262] The low rotational speed of the crank shaft 24 also gives the slow liquid-mechanical piston compressor-expander 1 according to the invention a service life of several decades, or even several centuries, subject to changing a few parts subject to aging such as the seal 51 of the hydraulic piston 10.

[0263] To continue the description of the operation of the slow liquid-mechanical piston compressor-expander 1 according to the invention and as shown in figures 6 to 9, we will consider here that a compressor 3 and an expander 4 formed from said slow compressor-expander 1 cooperate to form a heat pump 55 which executes a refrigeration cycle close to the ideal Carnot cycle.

[0264] In this respect, it is noted in figures 6 to 9 that the discharge plenum 62 of the compressor 3 is connected to the inlet plenum 21 of the expander 4 by a high-pressure gas conduit 56 so that the working gas 5 discharged via the discharge plenum 62 of said compressor 3 is introduced into said expander 4 via the inlet plenum 21 of said expander 4, the crank shaft 24 of said compressor 3 being connected to the crank shaft 24 of said expander 4.

[0265] It can be noted in [Fig.9] that the high pressure gas conduit 56 is connected to a high pressure gas reservoir 58 which can accumulate, by way of non-limiting example, working gas 5 whose temperature is forty degrees Celsius and whose pressure is forty-six bars absolute.

[0266] As such and as shown in [Fig.9], the high pressure gas conduit 56 and high pressure gas tank 58 can advantageously be coated with a thermal insulation layer 59 which prevents any unnecessary dissipation of heat into the external environment of the heat pump 55.

[0267] It is also noted in [Fig.9] that the intake plenum 21 of the compressor 3 and the discharge plenum 62 of the expander 4 communicate via a low-pressure gas reservoir 60 to which they are respectively connected by a low-pressure gas conduit 61.

[0268] By way of non-limiting example, the pressure and temperature of the working gas 5 contained in the low-pressure gas tank 60 are respectively one and a half bars absolute, and two degrees Celsius.

[0269] Still by way of non-limiting example and as shown in [Fig.9], we will assume here that the heating means 18 consist of a heating-cooling floor 106 in which a heat transfer fluid 37 circulates which transports heat from the compressor 3 to said floor 106, said fluid 37 entering said floor 106 at a temperature of thirty-five degrees Celsius so that the latter maintains a temperature of twenty-one degrees Celsius in a residential building 121, while the cooling means 19 are formed of an air-water exchanger 107 which is placed outside 122 of said building 121, and through which atmospheric air is forced to pass by two motor-fans 108, a heat transfer fluid 37 circulating in said exchanger 107 to transport heat from said exchanger 107 to the expansion valve 4, said fluid 37 entering said exchanger 107 at a temperature of two degrees Celsius while the outside temperature of the building 121 is seven degrees Celsius.

[0270] In relation to figures 6 to 8, we will also assume that the stroke of the hydraulic piston 10 of the compressor 3 and of the expander 4 is four hundred millimeters while the bore of the liquid cylinder 8 of said compressor 3 and of said expander 4 is four hundred and ten millimeters, said piston 10 and said cylinder 8 therefore forming a hydraulic variable volume 12 of fifty one point five liters.

[0271] [Fig.5] represents principle pressure-volume diagrams, the scales not necessarily being respected, as executed by the heat pump 55 which has just been described, the upper diagram being executed by the compressor 3 while the lower diagram is executed by the expander 4, the two said diagrams being virtually linked by the dotted arrows to reconstruct the diagram of the Carnot heat pump cycle.

[0272] With regard to the diagram of compressor 3, that is to say the top diagram of [Fig.5], section AB forms an adiabatic compression which makes it possible to raise the initial temperature T1 of the working gas 5 from two degrees Celsius to forty degrees Celsius, this latter temperature being noted T2.

[0273] In doing so, the pressure of the working gas 5 increases from one and a half bars to two point four bars.

[0274] The hydraulic piston 10 of the compressor 3 continuing its stroke towards its top dead center, the section BC forms an isothermal compression during which the pressure of the working gas 5 goes from two point four to forty-six bars while the temperature T2 of forty degrees Celsius of said gas 5 remains constant, said gas 5 giving up its heat Q1 as said heat is produced to the working liquid 13 and to the heat exchange and accumulation means 16.

[0275] Section CD corresponds to the transfer of the working gas 5 from the gas and liquid tank 14 of the compressor 3 to the high pressure gas tank 58 shown in [Fig.9], the temperature and pressure of said gas 5 being respectively forty degrees Celsius and forty-six bars.

[0276] Said transfer takes place successively via the compressor valve 52 of the port outlet 7 of compressor 3, its discharge plenum 62, and the high-pressure gas conduit 56.

[0277] Section DE of the diagram of compressor 3 illustrates the sudden drop in pressure that occurs in the gas and liquid reservoir 14 of compressor 3 when compressor valve 52 of outlet port 7 of said compressor 3 closes and immediately thereafter, compressor valve 52 of its inlet port 6 opens.

[0278] Section EA corresponds to the admission by the compressor 3 of working gas 5 from the low-pressure gas tank 60 shown in [Fig.9] successively via the low-pressure gas conduit 61, the inlet plenum 21, and the compressor valve 52 of the inlet port 6 of said compressor 3.

[0279] With regard to the diagram of the regulator 4, that is to say the diagram at the bottom of [Fig.5], the section FG corresponds to the transfer of the working gas 5 from the high-pressure gas tank 58 to the gas and liquid tank 14 of said regulator 4, the temperature T2 and the pressure of said gas 5 being respectively forty degrees Celsius and forty-six bars.

[0280] The GH section forms an adiabatic expansion which lowers the initial temperature T2 of the working gas 5 from forty degrees Celsius to two degrees Celsius, this latter temperature being noted Tl, while at the same time, the pressure goes from forty-six to approximately twenty-nine bars.

[0281] Then, section HI forms an isothermal expansion during which the pressure of the working gas 5 goes from twenty-nine bars to one and a half bars absolute while the temperature Tl of two degrees Celsius of said gas 5 remains constant, the latter taking heat Q2 from the working liquid 13 and from the heat exchange and accumulation means 16 to maintain its temperature close to two degrees Celsius.

[0282] Section LJ of [Fig.5] corresponds to the discharge of the working gas 5 contained in the gas and liquid tank 14 of the regulator 4 to the low-pressure gas tank 60, said gas 5 circulating for this purpose successively via a pilot-controlled regulator valve 54 which forms the draining means 22 of the outlet port 7 of said regulator 4, then via the discharge plenum 62 of said regulator 4, and finally, via the low-pressure gas conduit 61 which connects said regulator 4 to the low-pressure gas tank 60.

[0283] Section JF of the pressure-volume diagram of the regulator 4 illustrates the sudden increase in pressure which occurs in the gas and liquid reservoir 14 of said regulator 4 when the pilot-controlled regulator valve 54 which forms the draining means 22 of the outlet port 7 of said regulator 4 closes, while immediately afterwards, the pilot-controlled regulator valve 54 which forms the filling means 20 of the inlet port 6 of said regulator 4 opens to initiate a new cycle of the regulator 4.

[0284] Thus, the two pressure-volume diagrams shown in [Fig.5] cooperate to re- constitute the Carnot heat pump cycle by means of the working gas 5 whose state does not change, the compressor 3 executing the hot part of said cycle while the expander 4 executes the cold part of said cycle.

[0285] If the heat export Q1 and the heat export Q2 were perfect, the heating power of the heat pump 55 just described would be approximately seventeen kilowatts for a coefficient of performance of more than eight.

[0286] Once the friction losses induced by the various pivot connections which, as shown in Figures 1 to 3, in Figures 6 to 8, and in Figures 22 and 23, are subtracted, are made up of low-friction roller bearings 105, the coefficient of performance of said heat pump 55 drops to approximately seven point seven.

[0287] If the cooling means 19 consist of an air-water exchanger 107 as shown in [Fig.9], and the cumulative power consumed by the motor-fans 108 to force the thermal exchanges between the atmospheric air and the water circulating in said exchanger 107 is five hundred Watts, the coefficient of performance of said heat pump 55 drops to six point three.

[0288] Based on these observations, we understand the full interest of the particular mechanical configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention because, in fact, if, all other things being equal, said compressor-expander 1 had a conventional connecting rod which cooperates with a fixed liquid cylinder, even with a connecting rod / crank ratio of four, that is to say with a particularly bulky connecting rod 840 millimeters long, the coefficient of performance of the resulting heat pump would drop to approximately four, instead of the six point three accessible with said particular mechanical configuration of said slow compressor-expander 1 according to the invention.

[0289] Such a coefficient of performance would not be sufficiently different from that of conventional heat pumps to justify a change in technology, especially since such a Carnot cycle heat pump using a gas without phase change would likely be much heavier, bulkier and more cumbersome than its conventional counterpart.

[0290] The sole interest in replacing refrigerants such as hydrofluorocarbons with atmospheric air would not be sufficient to justify a change in technology because the carbon dioxide expected in the near future as a replacement for said fluids will remain environmentally acceptable.

[0291] On the other hand, a coefficient of performance of the order of six instead of four currently available represents an energy saving for the same service provided of thirty-three percent, which is very interesting both from an energy and economic point of view, as well as from an environmental point of view.

[0292] However, this coefficient of performance is not accessible with the compressor- slow liquid-mechanical piston expander 1 according to the invention only on condition that the heat exchanges Q1 and Q2 shown on the pressure-volume diagrams of [Fig.5] operate with great efficiency.

[0293] This is why, in Figures 1 to 4, in Figures 8 and 9, and in [Fig. 17], it has been shown that heat exchanger conduits 36 housed in the gas and liquid tank 14 of the compressor 3 and of the expander 4 can for example be formed from a winding of copper pipe 109 in which a heat transfer fluid 37 circulates, and constitute both the heat exchange and accumulation means 16 and the heat export or supply means 17.

[0294] According to this particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention, the heat exchanger conduits 36 take or give up heat to the working liquid 13 and to the working gas 5, then, the heat transfer fluid 37 which circulates in said conduits 36 transports said heat from the cooling means 19 or towards the heating means 18.

[0295] It can be seen in Figures 3 and 4 that the turns formed by the copper pipe winding 109 are held in place relative to each other by separation baffles 110 to which external fins could possibly be added which increase the contact surface of the heat exchanger conduit 36 ​​with the working liquid 13 or the working gas 5.

[0296] Also, when the hydraulic piston 10 is positioned at its bottom dead center and the pneumatic variable volume 2 is maximum, the working gas 5 is exposed to contact with the copper pipe winding 109 and its possible external fins, whereas when said piston 10 is at its top dead center and the pneumatic variable volume 2 is minimum, said winding 109 is immersed in the working liquid 13.

[0297] It has been shown in Figures 1 to 4, in [Fig.8], and in Figures 10 to 16, that the upper part of the gas and liquid reservoir 14 receives liquid spray nozzles 71 which atomize working liquid 13 into fine droplets in the internal volume of said reservoir 14, so that said liquid 13 forms an additional heat exchange and accumulation means 16 which takes or gives up heat to the working gas 5, particularly during the isothermal compression phase corresponding to the curve section BC of the pressure-volume diagram of [Fig.5] in the case of the compressor 3, and during the expansion phase corresponding to the curve section HI of said diagram in the case of the expander 4.

[0298] This particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention makes it possible to maximize the heat exchanges between the working gas 5 and the working liquid 13.

[0299] As can be seen in Figures 2 to 4, in [Fig.8], and in [Fig. 10] to 16, the nozzles of liquid spray 71 are supplied with working liquid 13 by a liquid spray pump 72 which consists of a pump cylinder 73 which houses a pump piston 74 set in motion by the hydraulic piston 10.

[0300] The operation of the liquid spray pump 72 of the compressor 3 according to a particular embodiment of said pump 72 is detailed in figures 10 to 12, while the operation of the liquid spray pump 72 of the expander 4 according to a particular embodiment of said pump 72 is detailed in figures 13 to 16, the details of said operations being, in view of said figures, obvious to those skilled in the art.

[0301] In Figures 3, 6 and 7, it can be seen that the discharge plenum 62 of the compressor 3 and the expander 4 formed by the slow liquid-mechanical piston compressor-expander 1 according to the invention communicates with an overflow tank 83, the lower part of which comprises an overflow pump 82.

[0302] According to this particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention, at each revolution of the crank shaft 24, the overflow pump 82 transfers a small quantity of working liquid 13 from the overflow tank 83 to the liquid cylinder 8 of the compressor 3 or, as the case may be, of the expander 4.

[0303] Said particular configuration allows that when the hydraulic piston 10 makes back and forth movements in the liquid cylinder 8 and when the hydraulic variable volume 12 is minimal, the gas and liquid reservoir 14 is completely filled with working liquid 13, the small quantity of working liquid 13 introduced by the overflow pump 82 into the gas and liquid reservoir 14 overflowing with each turn of the crank shaft 24 of said reservoir 14 to return to the overflow reservoir 83 via the outlet port 7 and the discharge plenum 62.

[0304] This particular embodiment of the slow liquid-mechanical piston compressor-expander 1 according to the invention allows all of the working gas 5 contained in the pneumatic variable volume 2 to be expelled from said volume 2 when the hydraulic variable volume 12 is minimal, which gives said pneumatic variable volume 2 an infinite volumetric ratio, and a volumetric efficiency close to one hundred percent.

[0305] As can easily be deduced from Figures 3, 6 and 7, whether it is the compressor 3 or the expander 4, the working gas pressure 5 which prevails in the overflow tank 83 is similar to that which prevails in the discharge plenum 62.

[0306] It can be seen in Figures 3, 6 and 7 that the overflow tank 83 is located below the discharge plenum 62 so that, due to the Earth's gravity, the working liquid 13 which overflows from the gas and liquid tank 14 via the outlet port 7 and the discharge plenum 62 naturally returns to said overflow tank. 83

[0307] Figures 17 to 19 show the overflow pump 82 as it can be provided for the compressor 3, according to a particular configuration of the slow liquid-mechanical piston compressor-expander 1 according to the invention.

[0308] As seen in said figures 17 to 19, the overflow pump piston 85 is a two-body stepped piston 89 which comprises a large diameter body 93 which has a large section face 90, the latter forming one of the walls of a variable overflow pump volume 86.

[0309] Figures 17 to 19 show that said stepped piston 89 also comprises, axially opposite the large section face 90, a small diameter body 94 which can translate in a sealed manner in an actuating cylinder 92 whose internal volume is connected to that of the gas and liquid reservoir 14 and the liquid cylinder 8, said small diameter body 94 having a small section face 91 on which the pressure prevailing in said cylinder 8 is exerted, said pressure being noted P2 in Figures 18 and 19.

[0310] It is also noted in Figures 17 to 19 that said stepped piston 89 has, at the junction between the large diameter body 93 and the small diameter body 94, a medium section face 95 from which the small diameter body 94 emerges, said face 95 being connected to the overflow reservoir 83 and being subjected to the pressure prevailing in said reservoir 83 denoted PI in Figures 18 and 19, while a stepped piston stop 117 fixes the maximum volume of the variable volume of the overflow pump 86 and a two-body piston return spring 96 tends to push the two-body stepped piston 89 towards its large section face 90.

[0311] Thus and as is easily understood from [Fig. 18], when the pressure P2 which prevails in the liquid cylinder 8 is lower than the pressure PI, which prevails in the overflow tank 83, the two-body stepped piston 89 is kept pressed against the stepped piston stop 117 while the two-body piston return spring 96 is compressed by the force produced by the pressure differential PI minus P2 exerted on the entire surface of the small section face 91, the discharge valve 88 being closed.

[0312] When the hydraulic piston 10 of the compressor 3 reaches the top dead center, the pressure P2 which prevails in the liquid cylinder 8 becomes substantially equal to the pressure PI which prevails in the overflow tank 83, there is no longer any force exerted on the small section face 91, and the two-body piston return spring 96 pushes back the two-body stepped piston 89 as shown in [Fig. 19], which has the effect of expelling working liquid 13 from the variable volume of the overflow pump 86 to the liquid cylinder 8 via the open discharge valve 88, the effective energy consumption of the transfer of said liquid 13 from said volume 86 towards said cylinder 8 being very low.

[0313] When the hydraulic piston 10 of the compressor 3 begins to descend, which corresponds to the section DE of the pressure-volume diagram of [Fig.5], the discharge valve 88 is calculated to close immediately when the pressure P2 prevailing in the liquid cylinder 8 becomes lower than the pressure PI prevailing in the overflow tank 83.

[0314] This is followed by the compression of the two-body piston return spring 96 by the two-body stepped piston 89, the latter moving under the effect of the pressure differential PI minus P2 which is exerted on the small section face 91 with, in parallel, the increase in the variable volume of the overflow pump 86 into which a new charge of working liquid 13 is admitted from the overflow tank 83 and via the overflow pump inlet valve 87.

[0315] As noted in Figures 18 and 19, the discharge valve 88 includes a valve actuator piston 97 which can translate sealingly in a valve actuator cylinder 98.

[0316] Said piston 97 has an axial valve actuating face 99 which communicates with the overflow reservoir 83 and on which the pressure PI prevailing in said reservoir 83 is exerted.

[0317] As seen in [Fig. 19], said axial face 99 may contact an overflow valve 100 to lift the latter from an overflow valve seat 104 when the valve actuator piston 97 moves toward said face 99.

[0318] In this case and taking into account the particular position of the overflow pump 82 shown in [Fig.3] and in figures 6 and 7, the variable volume of the overflow pump 86 is put into communication with the gas and liquid reservoir 14 via said overflow valve 100.

[0319] It is also noted in Figures 18 and 19 that the valve actuator piston 97 also has an axial face on the liquid cylinder side 102 which communicates with the gas and liquid reservoir 14 and on which the pressure P2 prevailing in said reservoir 14 and in the liquid cylinder 8 is exerted, said face being able to come into contact, as shown in [Fig. 18], with a stop on the liquid cylinder side 118 when the valve actuator piston 97 moves towards said axial face on the liquid cylinder side 102.

[0320] In Figures 18 and 19, it is noted that an actuating piston return spring 103 tends to push the valve actuator piston 97 towards its axial valve actuating face 99, and that an overflow valve return spring 128 tends to bring the overflow valve 100 back into contact with the overflow valve seat 104 with which it cooperates.

[0321] As can be easily deduced from Figures 18 and 19, for the discharge valve 88 to operate, the force produced by the actuating piston return spring 103 must be greater than the force produced by the overflow valve return spring 128.

[0322] Thus and as is easily understood from Figures 18 and 19, when the pressure P2 which prevails in the gas and liquid reservoir 14 and the liquid cylinder 8 is lower than the pressure PI which prevails in the overflow reservoir 83, the axial face on the liquid cylinder side 102 of the valve actuator piston 97 is kept pressed against the stop on the liquid cylinder side 118 while the actuating piston return spring 103 is compressed by the force produced by the pressure differential PI minus P2 between that which is exerted on the axial valve actuating face 99 and that which is exerted on the axial face on the liquid cylinder side 102.

[0323] In this case, the overflow valve 100 rests on its overflow valve seat 104, and the working liquid 13 cannot circulate between the variable volume overflow pump 86 and the liquid cylinder 8.

[0324] When the hydraulic piston 10 of the compressor 3 reaches the top dead center, the pressure P2 which prevails in the liquid cylinder 8 becomes substantially equal to the pressure PI which prevails in the overflow tank 83, and the pressure which is exerted on the axial face of valve actuation 99 is equivalent to that which is exerted on the axial face on the liquid cylinder side 102.

[0325] As a result of this situation, the actuating piston return spring 103 pushes the valve actuator piston 97 towards the overflow valve 100, until the axial valve actuating face 99 comes into contact with said valve 100 and then lifts the latter from its overflow valve seat 104, and this, until said valve 100 reaches a maximum valve opening stop 131.

[0326] With the overflow valve 100 moved away from its overflow valve seat 104, the two-body stepped piston 89 can move under the action of its two-body piston return spring 96, and expel working liquid 13 from the variable overflow pump volume 86 to the gas and liquid reservoir 14.

[0327] When the hydraulic piston 10 of the compressor 3 begins to descend, which corresponds to the section DE of the pressure-volume diagram of [Fig. 5], the pressure P2 prevailing in the gas and liquid reservoir 14 and the liquid cylinder 8 becomes lower than the pressure PI prevailing in the overflow reservoir 83.

[0328] This situation results in the compression of the actuating piston return spring 103 by the valve actuator piston 97, the latter moving under the effect of the pressure differential PI minus P2 between that which is exerted on its axial valve actuating face 99 and that which is exerted on its axial face on the liquid cylinder side 102, said piston 97 leaving the overflow valve return spring 128 bring the overflow valve 100 back into contact with its overflow valve seat 104.

[0329] It can be seen in Figures 20 and 21 that the overflow pump 82 of the pressure reducer 4 is based on the same principles as those which have just been described, with the difference that the transfer of working liquid 13 from the overflow tank 83 to the liquid cylinder 8 takes place not when the hydraulic piston 10 reaches its top dead center, but when said piston 10 reaches its bottom dead center.

[0330] This comes from the fact that the cycle of the compressor 3 operates on average at a lower pressure than that prevailing in the discharge plenum 62 of said compressor 3, while the cycle of the expander 4 operates on average at a higher pressure than that prevailing in the discharge plenum 62 of said expander 4.

[0331] [Therefore, in order for the filling of the variable volume of the overflow pump 86 to take place, the operation with respect to the pressure differences of the overflow pump 82 of the compressor 3 must preferably be reversed with respect to that of the overflow pump 82 of the expander 4.

[0332] As can easily be deduced from [Fig.9], the control of the heat pump 55 is carried out mainly by adjusting the rotation speed of the crank shaft 24 and by adapting the lifting laws of the controlled expansion valves 54, the latter each being actuated in opening and / or closing by a valve actuator 119, said control of said speed and of said actuator 119 being ensured by a computer 120.

[0333] Because in fact, all other things being equal, the power of the heat pump 55 is proportional to the rotation speed of its crank shaft 24, which is a first adjustment which allows the computer 120 to adjust said power.

[0334] But in addition to the rotation speed of its crank shaft 24, the more or less late and more or less spread out lifting of the pilot-controlled pressure reducer valves 54 makes it possible in particular to adjust the pressure which prevails in the low-pressure gas reservoir 60 relative to that which prevails in the high-pressure gas reservoir 58.

[0335] This adjustment is of great importance in that the pressure differential in question determines in particular the quantity of heat produced by the heat pump 55 at each revolution of the crank shaft 24.

[0336] This adjustment is carried out for example by having the regulator 4 transfer less working gas 5 from the high-pressure gas reservoir 58 to the gas and liquid reservoir 14 during section FG of the diagram of said regulator 4 in [Fig. 5], than the compressor 3 transfers during section CD of said diagram, which has the effect of increasing the pressure in the high-pressure gas reservoir 58 while decreasing the pressure in the low-pressure gas reservoir 60.

[0337] If, on the contrary, the regulator 4 transfers more working gas 5 from the high-pressure gas tank 58 to the gas and liquid tank 14 during the FG section of the diagram of said regulator 4 of [Fig.5], that the compressor 3 transfers during section CD of said diagram, the pressure in the high pressure gas tank 58 drops while the pressure in the low pressure gas tank 60 rises.

[0338] It will be noted that advantageously, the pilot-operated pressure reducing valves 54 can behave both as valves and as flaps, that is to say that they can open under the effect of a pressure differential, in addition to being actuated in opening by their valve actuator 119.

[0339] In this respect, said valves 54 are preferably autoclaves, that is to say that during the majority of the time of the thermodynamic cycle of the expander 4, the pressure difference between the inlet plenum 21 of said expander 4 and its gas and liquid reservoir 14, or that between the discharge plenum 62 of said expander 4 and said reservoir 14, tends to keep said valves 54 pressed against their seat, the latter being able for example to be made up of an elastomer or polymer O-ring housed in a groove.

[0340] If, on the other hand, the pressure prevailing in the gas and liquid reservoir 14 of the regulator 4 becomes higher than that prevailing in the inlet plenum 21 of said regulator 4, the pilot-operated regulator valve 54 can open without intervention of its valve actuator 119.

[0341] The same applies to the pilot-controlled pressure reducer valve 54 which communicates with the discharge plenum 62 of said pressure reducer 4 via its outlet port 7, said valve 54 being able to open without intervention of its valve actuator 119 if the pressure prevailing in said plenum 62 becomes higher than that prevailing in the gas and liquid reservoir 14 of said pressure reducer 4.

[0342] It is easily deduced from [Fig.9] that the heat pump 55 can operate in “heating” mode when the heating-cooling floor 06 placed inside a building 121 forms the heating means 18 which are connected to the heat export or supply means 17 of the compressor 3, while the air-water exchanger 107 placed outside 122 of said building 121 constitutes the cooling means 19 which are connected to the heat export or supply means 17 of the expansion valve 4.

[0343] If the heat pump 55 operates in “air conditioning” mode, the heating-cooling floor 06 placed inside said building 121 forms the cooling means 19 which are connected to the heat export or supply means 17 of the expansion valve 4, while the air-water exchanger 107 placed outside 122 of said building 121 constitutes the cooling means 19 which are connected to the heat export or supply means 17 of the compressor 3.

[0344] The change of mode can easily be carried out by reversing the heat transport conduits 38 using one or more manual or motorized valves, whatever the type, said conduits 38 initially connected to the compressor 3 becoming connected to the regulator 4, and vice versa.

[0345] It will be noted that the slow liquid-mechanical piston compressor-expander 1 according to the invention and the resulting heat pump 55 may, in addition to the various components and accessories shown in FIGS. 1 to 4 and in FIGS. 6 to 23, comprise various other devices and accessories such as pressure and / or temperature sensors, a frequency converter for regulating the electrical supply of the electric drive motor 27, at least one angular encoder and / or a passage detection sensor which returns to the computer 120 the speed and / or the angular position of the crank shaft 24, one or more pumps and / or compressors and / or valves for transferring working gas 5 or working liquid 13 from external sources to the high-pressure gas tank 58 or the low-pressure gas tank 60 or between said tanks 58, 60, purges, safety elements for people,pressure limiters or relief valves, or any other apparatus known to those skilled in the art.

[0346] The heat pump 55 formed from the slow liquid-mechanical piston compressor-expander 1 according to the invention may also include a thermal insulation layer 59 on all the necessary components, and whatever the nature of said layer 59 which may take the form of flexible or rigid insulating foam or wool, bricks, plates or screens which reflect radiation of any nature.

[0347] The thermal insulation layer 59 can isolate the heat pump 55 and its constituents from the environment outside said pump 55 and / or isolate the compressor 3 which is hot, from the expansion valve 4 which is colder.

[0348] The heat pump 55 can also receive an acoustic insulation envelope, and its static frame 40 can rest on the ground by means of elastic anti-vibration pads.

[0349] The possibilities of the slow liquid-mechanical piston compressor-expander 1 according to the invention are not limited to the applications which have just been described and it must also be understood that the preceding description has been given only by way of example and that it in no way limits the scope of said invention, which would not be departed from by replacing the execution details described by any other equivalent.

Claims

1. Claims Slow liquid-mechanical piston compressor-expander (1) defining a pneumatic variable volume (2) which forms a compressor (3) or an expander (4), a working gas (5) being able to enter said volume (2) via an inlet port (6) or leave said volume (2) via an outlet port (7), characterized in that it comprises: • A liquid cylinder (8) which can, directly or indirectly, pivot around a tilting axis (9) which is perpendicular to the axis of said cylinder (8) and which is secured to a static frame (40); • A hydraulic piston (10) which can translate in a sealed manner in the liquid cylinder (8) to form with the latter a variable hydraulic volume (12) which is completely or partially filled with a working liquid (13); • A gas and liquid reservoir (14) which is connected to the hydraulic variable volume (12) by a communication conduit (15), so that said reservoir (14) fills mainly or completely with working liquid (13) when the hydraulic variable volume (12) is minimal, and fills partially or completely with working gas (5) when the hydraulic variable volume (12) is maximal, the absolute volume variation of the working gas (5) contained in the pneumatic variable volume (2) forming on the one hand, the pneumatic variable volume (2), and being on the other hand, approximately equal to the absolute volume variation of the working liquid (13) contained in the hydraulic variable volume (12); • Heat exchange and accumulation means (16) housed in the gas and liquid reservoir (14), said means (16) being able, on the one hand, to exchange heat with the working gas (5) or with the working liquid (13) and, on the other hand, to temporarily store all or part of said heat; • Heat export or supply means (17) which take or transfer heat directly or indirectly to the heat exchange and accumulation means (16) and / or to the working liquid (13) and / or to the working gas (5), said taken heat then being transferred to heating means (18) or said transferred heat having been previously taken from cooling means (19), said heating means (18) and said cooling means (19) being external to the gas and liquid reservoir (14); • Filling means (20) which allow or prevent the passage of working gas (5) from an inlet plenum (21) to the gas and liquid reservoir (14) via the inlet port (6); • Draining means (22) which allow or prevent the passage of working gas (5) from the gas and liquid reservoir (14) to a discharge plenum (62) via the outlet port (7); • A connecting rod (11) of which a first rod end (29) is fixedly secured to the hydraulic piston (10), said rod (11) being approximately parallel to the longitudinal axis of said piston (10); • Piston guide means (23) which keep the hydraulic piston (10) and the connecting rod (11) parallel to said cylinder (8), regardless of the position of said piston (10) in said cylinder (8);• A crank shaft (24) which can rotate about an axis parallel to the tilting axis (9) in at least one shaft bearing (25), and which has at least one crank (26) around which a second rod end (30) of the connecting rod (11) is articulated; • At least one drive motor (27) which directly or indirectly drives the crank shaft (24) in rotation; • Kinetic energy storage means (28) which are directly or indirectly connected to the crank shaft (24).;

2. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the tilting axis (9) is a tubular ball joint (111) which terminates the liquid cylinder (8) and the interior of which forms in whole or in part the communication conduit (15), said ball joint (111) being able to pivot in a sealed manner in a female ball joint housing (123) secured to the gas and liquid tank (14).

3. Slow liquid-mechanical piston compressor-expander according to claim dication 2, characterized in that the tubular ball joint (111) receives in its center a ball joint axis (124) which is parallel to the tilting axis (9), said axis (124) being articulated around a ball joint hanger (125) which is directly or indirectly secured to the gas and liquid tank (14).

4. Slow liquid-mechanical piston compressor-expander according to claim 3, characterized in that the ball joint hanger (125) is connected to the gas and liquid tank (14) by means of an articulated hanger connection (126) around which said hanger (125) can rotate.

5. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the liquid cylinder (8) and the gas and liquid reservoir (14) form a rigid assembly (31) which pivots around the tilting axis (9).

6. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the heat exchange and accumulation means (16) consist of a porous medium (32) which has porosities (33) into which the working liquid (13) and the working gas (5) enter and exit alternately.

7. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the heat export or supply means (17) consist of a circulating part of the working liquid (13), said part leaving the liquid cylinder (8) or the gas and liquid reservoir (14) via a liquid outlet conduit (34) to return to said cylinder (8) or to said reservoir (14) via a liquid inlet conduit (35), this after having given up heat to the heating means (18) or after having taken heat from the cooling means (19).

8. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the heat export or supply means (17) consist of at least one heat exchanger conduit (36) housed in the gas and liquid tank (14) and in which circulates a heat transfer fluid (37) which transports the heat taken or transferred to the heat exchange and accumulation means (16) and / or to the working liquid (13) and / or to the working gas (5) to the cooling means (19) or to the heating means (18) via heat transport conduits (38).

9. Slow liquid-mechanical piston compressor-expander according to claim dication 1, characterized in that the heat exchange and accumulation means (16) consist of at least one liquid spray nozzle (71) supplied by a liquid spray pump (72), said nozzle (71) being able to atomize working liquid (13) into fine droplets in the internal volume of the gas and liquid reservoir (14).

10. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the tilting axis (9) consists of a rolling track (41) which is integral with the static frame (40) and on which a rolling surface (42) can roll which is directly or indirectly integral with the liquid cylinder (8), a rolling track toothed wheel (43) whose pitch circle (44) coincides with the line of contact between the rolling track (41) and the rolling surface (42) being integral with the static frame (40) and cooperating with a rolling surface toothed wheel (45) which is directly or indirectly integral with the liquid cylinder (8).

11. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the piston guide means (23) consist of a sliding pivot connection (47) formed between an external cylindrical surface (48) presented by the connecting rod (11) and a sliding ring (49) which is integrally connected to the liquid cylinder (8) via a ring-carrying structure (50).

12. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the piston guide means (23) consist of a guide skirt (57) arranged on the periphery of the hydraulic piston (10), said skirt (57) being able to translate with little play in said cylinder (8).

13. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the filling means (20) and / or the emptying means (22) consist of at least one compressor valve (52) and / or at least one compressor pilot valve (53) while in operation, the working gas (5) is expelled from the gas and liquid tank (14) via the discharge plenum (62) under a pressure higher than that under which it was previously introduced into said tank (14) via the inlet plenum (21) while the heat export or supply means (17) transfer heat to the heating means (18), so that the pneumatic variable volume (2) forms a compressor (3).

14. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the filling means (20) and / or the emptying means (22) consist of at least one pilot-controlled expander valve (54) while in operation, the working gas (5) is expelled from the gas and liquid tank (14) via the discharge plenum (62) under a pressure lower than that under which it was previously introduced into said tank (14) via the inlet plenum (21) while the heat export or supply means (17) take heat from the cooling means (19), so that the pneumatic variable volume (2) forms an expander (4).

15. Slow liquid-mechanical piston compressor-expander according to claims 13 and 14, characterized in that the discharge plenum (62) of the compressor (3) is connected to the inlet plenum (21) of the expander (4) by a high-pressure gas conduit (56) so that the working gas (5) discharged via the discharge plenum (62) of said compressor (3) is introduced into said expander (4) via the inlet plenum (21) of said expander (4), the crank shaft (24) of said compressor (3) being directly or indirectly connected to the crank shaft (24) of said expander (4), said compressor (3) and said expander (4) cooperating to form a heat pump (55).

16. Slow liquid-mechanical piston compressor-expander according to claim 15, characterized in that the high-pressure gas conduit (56) is connected to at least one high-pressure gas reservoir (58).

17. Slow liquid-mechanical piston compressor-expander according to claim 15, characterized in that the inlet plenum (21) of the compressor (3) and the discharge plenum (62) of the expander (4) communicate via a low-pressure gas reservoir (60) to which they are respectively connected by a low-pressure gas conduit (61).

18. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the inlet plenum (21) and the discharge plenum (62) are positioned in the upper part of the gas and liquid tank (14), the latter itself being positioned above the liquid cylinder (8) so that due to the Earth's gravity, the working gas (5) always leaves the gas and liquid tank (14) as a priority via the discharge plenum (62), and the working liquid (13) always enters said tank (14) as a priority via the inlet plenum.

19. Slow liquid-mechanical piston compressor-expander according to claim 5, characterized in that the tilting axis (9) consists of a hollow cylindrical axis (63) which has at least one through-radial port (64), said cylindrical axis (63) being positioned above the gas and liquid reservoir (14), while the inlet plenum (21) and / or the discharge plenum (62) is connected to an annular gas collector (65) which surrounds said cylindrical axis (63) and which includes the through-radial port (64) so ​​that the working gas (5) can circulate between the interior of the hollow cylindrical axis (63) and the inlet plenum (21) and / or the discharge plenum (62) via the through-radial port (64) and the annular gas collector (65).

20. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that the kinetic energy storage means (28) consist of a low-speed flywheel (66) which is integral in rotation, on the one hand, with the crank shaft (24), and on the other hand, with a toothed crown (67) which the drive motor (27) drives in rotation by means of at least one crown drive pinion (68) whose primitive diameter is smaller than that of said crown (67), the latter and said pinion (68) forming a high-reduction gear system (69), while a high-speed flywheel (70) is directly or indirectly integral in rotation with the crown drive pinion (68).

21. Slow liquid-mechanical piston compressor-expander according to claim 9, characterized in that the liquid spray pump (72) consists of a pump cylinder (73) which is arranged in the liquid cylinder (8) and / or in the extension of said cylinder (8), a pump piston (74) set in motion by the hydraulic piston (10) and / or by the liquid cylinder (8) being able to translate in said pump cylinder (73).

22. Slow liquid-mechanical piston compressor-expander according to claim 21, characterized in that the pump piston (74) comprises a start-of-stroke button (77) by means of which it is set in motion, said piston (74) being returned to an end-of-stroke stop (78) by a piston return mass (76).

23. Slow liquid-mechanical piston compressor-expander according to claim 21, characterized in that the pump piston (74) is set in motion by means of a setting spring (81).

24. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that, at each revolution of the crank shaft (24), an overflow pump (82) transfers a small quantity of working liquid (13) from an overflow tank (83) to the gas and liquid tank (14) and / or the liquid cylinder (8).

25. Slow liquid-mechanical piston compressor-expander according to claim 24, characterized in that the overflow tank (83) communicates with the discharge plenum (62), the working gas pressure (5) which prevails in said tank (83) being close to or identical to that which prevails in said plenum (62).

26. Slow liquid-mechanical piston compressor-expander according to claim 24, characterized in that the overflow pump (82) comprises a blind pump cylinder (84) in which an overflow pump piston (85) can translate in a sealed manner, the latter and said cylinder (84) forming a variable overflow pump volume (86) which, when it increases, fills with working liquid (13) from the overflow tank (83) via at least one overflow pump inlet valve (87) and which, when it decreases, discharges said liquid (13) towards the gas and liquid tank (14) and / or the liquid cylinder (8) via a discharge valve (88).

27. ​​Slow liquid-mechanical piston compressor-expander according to claim 26, characterized in that the overflow pump piston (85) is a two-body stepped piston (89) which comprises a large-diameter body (93) which has a large-section face (90) which forms one of the walls of the variable overflow pump volume (86), said stepped piston (89) also comprising, axially opposite the large-section face (90), a small-diameter body (94) which can translate in a sealed manner in an actuating cylinder (92) whose internal volume is connected directly or indirectly to that of the liquid cylinder (8), said small-diameter body (94) having a small-section face (91) on which the pressure prevailing in the liquid cylinder (8) is exerted, said stepped piston (89) also offering, at the junction between the large-diameter body (93) and the small-diameter body (94),a medium section face (95) from which emerges the small diameter body (94), which is connected to the overflow tank (83), and which is subjected to the pressure prevailing in said tank (83), while a stepped piston stop (117) fixes the maximum volume of the variable volume of the overflow pump (86) and a spring of, two-body piston return (96) tends to push the two-body stepped piston (89) towards its large section face (90).

28. Slow liquid-mechanical piston compressor-expander according to claim 27, characterized in that the discharge valve (88) comprises a valve actuator piston (97) which can translate in a sealed manner in a valve actuator cylinder (98) and which has, firstly, an axial valve actuator face (99) which communicates with the overflow tank (83) and on which the pressure prevailing in said tank (83) is exerted, said face (99) being able to lift an overflow valve (100) from an overflow valve seat (104) when the valve actuator piston (97) moves towards said face (99) which has the effect of putting the variable volume of the overflow pump (86) into communication with the gas and liquid tank (14) and / or the liquid cylinder (8) via said overflow valve (100), and secondly part, an axial face on the liquid cylinder side (102) which communicates with the liquid cylinder (8),on which the pressure prevailing in said cylinder (8) is exerted, and which can come into contact with a stop on the liquid cylinder side (118) when the valve actuator piston (97) moves towards said axial face on the liquid cylinder side (102), while an actuating piston return spring (103) tends to push the valve actuator piston (97) back towards its axial valve actuating face (99), and an overflow valve return spring (128) tends to bring the overflow valve (100) back into contact with the overflow valve seat (104) with which it cooperates, the force produced by the actuating piston return spring (103) being greater than the force produced by the overflow valve return spring (128).,

29. Slow liquid-mechanical piston compressor-expander according to claim 26, characterized in that the overflow pump piston (85) is a two-body stepped piston (89) which comprises a large-diameter body (93) which has a large-section face (90) which is connected to the overflow reservoir (83) and which is subjected to the pressure prevailing in said reservoir (83), said stepped piston (89) also comprising, axially opposite the large-section face (90), a small-diameter body (94) which can translate in a sealed manner in an actuating cylinder (92) whose internal volume is connected directly or indirectly to that of the liquid cylinder (8), said small-diameter body (94) having a small-section face (91) on which the pressure prevailing in the liquid cylinder (8) is exerted, said stepped piston (89) also offering, at the junction between the large diameter body (93) and the small diameter body (94), a medium section face (95) from which emerges the small diameter body (94), said face (95) forming one of the walls of the variable volume of the overflow pump (86), while a stepped piston stop (117) fixes the maximum volume of the variable volume of the overflow pump (86) and a two-body piston return spring (96) tends to push the two-body stepped piston (89) towards its small section face (91).

30. Slow liquid-mechanical piston compressor-expander according to claim 29, characterized in that the discharge valve (88) comprises a valve actuator piston (97) which can translate in a sealed manner in a valve actuator cylinder (98) and which has, firstly, an axial valve actuator face (99) which communicates with the liquid cylinder (8) and on which the pressure prevailing in said cylinder (8) is exerted, said face (99) being able to lift an overflow valve (100) from an overflow valve seat (104) when the valve actuator piston (97) moves towards said face (99) which has the effect of putting the variable volume of overflow pump (86) into communication with the gas and liquid reservoir (14) and / or the liquid cylinder (8) via said overflow valve (100), and secondly, a axial face on the tank side (101) which communicates with the overflow tank (83),on which the pressure prevailing in said reservoir (83) is exerted, and which can come into contact with a stop on the overflow reservoir side (130) when the valve actuator piston (97) moves towards said axial face on the reservoir side (101), while an actuating piston return spring (103) tends to push the valve actuator piston (97) back towards its axial valve actuating face (99), and an overflow valve return spring (128) tends to bring the overflow valve (100) back into contact with the overflow valve seat (104) with which it cooperates, the force produced by the actuating piston return spring (103) being greater than the force produced by the overflow valve return spring (128).,

31. Slow liquid-mechanical piston compressor-expander according to claim 1, characterized in that counterbalancing means (112) replace in whole or in part the piston guide means (23) to tilt the liquid cylinder (8) during rotation of the shaft. crank (24).

32. Slow liquid-mechanical piston compressor-expander according to claim 31, characterized in that the counterbalancing means (112) consist of a counterbalancing mast (113) which, on the one hand, comprises a counterbalancing mass (116) and which, on the other hand, is articulated around a mast axis (114) which is parallel to the tilting axis (9) of the liquid cylinder (8) and which is integral with the static frame (40), while the counterbalancing mast (113) forms with said cylinder (8) a pivoting-sliding articulation (115) and constitutes an unbalance opposite to that of said cylinder (8).

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