Pneumatic turbo device for recovering and regenerating residual pneumatic energy from the exhausts of systems using compressed air.

Abstract

Device for recovering and regenerating residual pneumatic energy from exhausts, which connects as an additional kit to a Filter Regulator (Lubricator) group, and to the locations of the silencers, of a pneumatic system. The invention mainly concerns an adjustable device, allowing in steady state to recover the potential energy of the exhausts and to regenerate it. The device uses a venturi controlled by non-return valves which govern the operation of a turbo pump supplied by the distribution network upstream of the FR(L) group, during its operation this will suck in the exhaust air evacuated by the actuators before re-compressing it then re-injecting it downstream of the spring regulator of an FR(L) group at a pressure fairly close to the set value. The device according to the invention is intended to improve the efficiency as well as the cleanliness of compressed air pneumatic systems.Figure for abstract: Figure 1.

Description

Title of the invention: Turbo pneumatic device for recovering and regenerating residual pneumatic energy from the exhausts of systems using compressed air. Technical field

[0001] The present invention relates to a turbo pneumatic device for recovering and regenerating residual pneumatic energy from the exhausts of air-using systems.

[0002] The invention also relates to a device for recovering and regenerating residual pneumatic energy from exhausts comprising a compressed air turbo pump for viscous fluid.

[0003] The invention also relates to an embodiment of such a device for recovering and regenerating residual pneumatic energy from exhausts. Technological background

[0004] The compressed air used and / or discharged by pneumatic tools as well as by pre-actuators (distributors, etc.), and actuators (cylinders, motors, gripping tools and vacuum gripping, etc.) of automated pneumatic systems is traditionally vented to the atmosphere, i.e. expelled via an exhaust silencer directly into the ambient air. This is one of the major advantages of pneumatic energy: there is no need to provide a return circuit as in hydraulics, or electricity, for example; but this advantage, however, leads to a loss of energy efficiency and jolts during the initial pressurization of the circuit (often a progressive pressurization valve proves essential).

[0005] It can easily be seen that the compressed air exhausted contains non-zero pneumatic energy; in fact, to be able to be discharged or expelled by a pneumatic system or pneumatic tools, the exhaust air must be at a pressure higher than atmospheric pressure, therefore higher than 1 bar absolute.

[0006] Very often the air discharged at the exhaust exceeds 2 bars absolute or even more, especially in the case of empty operation or very low load. Pneumatic equipment manufacturers are obliged to take safety margins, and to design actuators which, in order to be able to function, must, in addition to the nominal work to be carried out, be capable of indirectly evacuating the exhaust air via electropneumatic distributors themselves, mounted on centralized exhaust manifolds (equipped with exhaust silencers); all at a pressure obviously higher than 1 bar absolute at the silencer outlet.

[0007] One of the notable drawbacks and limitations of pneumatics is the great difficulty of feedback loop control, a case which arises when precision and repeatability are required, particularly for precision and robotic applications with parallel-mounted actuators which must operate almost synchronously.

[0008] Furthermore, the exhaust air is in practice neither cleaned nor filtered and despite the presence of exhaust silencers, it represents a source of fatigue due to the repetitive and omnipresent exhaust noises, and what is more, this exhaust air is a source of atmospheric pollution (particles from worn seals, rust, oils, and various vaporizations based on air, water, and stagnant oils, etc.), harmful to personnel, especially in confined areas and factories.

[0009] Finally, this pneumatic energy rejected by the exhausts is similar in a certain way to a net loss of energy efficiency; because a significant part of the outside air which has been pre-filtered, sucked in and compressed by the compressors then cooled, and partly dried by different devices or processes, and then once again finely filtered, and sometimes oiled, is released back into the atmosphere without having provided any useful work, this represents the main cause of the poor efficiency of the pneumatic energy and that of the accelerated wear of the compressors and of a large part of the excess electricity consumption, not caused by leaks on the pneumatic circuits.

[0010] The aim of the present invention is to partially resolve the drawbacks described above. State of the art

[0011] In pneumatics, compressed air (is a compressible fluid, most often outside air, which is compressed using a compressor, by reducing its initial volume (a bit like a spring), it is made to store potential mechanical energy, which can be used by pneumatic actuators, which take from this compressed air the necessary quantity of pneumatic energy to carry out the expected work, then they evacuate this used air (which still contains residual pneumatic energy that has not been used).

[0012] In industrial pneumatic installations, the compressed air distribution pressure is regulated so as to be almost constant at around 7 relative bars; up to each point of use; and each point of use is equipped with an FRL group: Filter, Regulator (Adjustable pressure reducer), and sometimes also Lubricator, which usually delivers a pressure of 6 bars relative to pneumatic automated systems, however the pressure (and therefore also the compressed air consumption) required by the actuators of these systems is very variable; in doing so the pressure of the evacuated air (also called exhaust) is also very variable.

[0013] One of the peculiarities of the normal operation of a spring regulator, see [Fig.4], is that by its construction, and that as the demand for compressed air from the actuators increases, its passage section (outlet) increases; which causes downstream of this regulator, a continuous and progressive drop in pressure and flow rate, which causes upstream of this regulator, a massive call for air from the distribution network; in general this causes by chain reaction, a drop in the pressure of the compressed air buffer tanks of the pneumatic installation, then the restarting of the compressor(s), these having to compensate for the drop in pressure and flow rate of the distribution network, by compressing more air to maintain the buffer tanks at a sufficient pressure (for example 10 bars relative), in order to maintain the distribution network at a working pressure of 7 bars relative (for example).

[0014] The device of the invention takes advantage of this particularity of the operation of spring regulators for its own operation. Summary of the invention

[0015] To this end, according to a first aspect of the invention, a device is proposed for recovering and regenerating residual pneumatic energy from the exhausts, this device comprises a turbo pump for suctioning the exhausts, the rotation speed of which can be adjusted using a flow adjustment needle valve.

[0016] the device can be fitted as an additional kit to an FRL group, and connected to the initial locations of the silencers, of a pneumatic system.

[0017] The device of the invention starts operating from the established regime, that is to say in the operating zone where the inertias have been overcome and where the demand for compressed air is the greatest, the pneumatic system then operates at full speed and at reduced load, this causes a notable pressure drop downstream of the spring regulator of the FRL group. This pressure drop downstream of the regulator then allows the pressure of the compressed air coming from the outlet of stages 1 and 3 of the device's particular turbopump (and supplied by the distribution network), to open the non-return, outlet and suction valves of the "piloted venturi", which allows the turbopump to start.

[0018] The 2nd stage of the turbo pump (i.e. the pump) will then, by suction, open the non-return valve of the “main collector” and suck in the exhausts (as well as the residual energy they contain)

[0019] Then the turbine part (stages 1 and 3) of the turbo pump will use the pneumatic energy coming from the distribution network (at 7 relative bars) and convert part of this pneumatic energy into rotational kinetic energy, which the pump part (stage 2) connected integrally to the turbine part, will use to compress more the exhaust air sucked in, in doing so the volume of the exhaust air sucked in will gradually be reduced (it will therefore re-store potential mechanical energy), until it is re-injected downstream of the regulator at an adequate pressure of around 5 to 5.5 bars which are values ​​quite close to the set value of the spring regulator (namely 6 relative bars).

[0020] The device of the invention will therefore make it possible, in steady state, to recover the potential energy of the exhausts and to regenerate it.

[0021] During the recirculation phase, the exhaust air whose pneumatic energy has been regenerated is purified before its reinjection downstream of the regulator, in order to rid it as best as possible of its proportion of water in the liquid phase, and of its used oils and suspended particles; for this purpose, filters and water separators are used, preferably with automatic purges, connected to a centralized network for recovering water and oil condensates; this will probably result in a compressed air leak rate, but negligible in view of the quantity of exhaust air recirculated and the role of this compressed air in keeping the purge pipes clean and operational.

[0022] Another advantage provided by the device of the invention is that when the regime is established, and the turbo pump starts operating; the exhausts are sucked, thereby the tools and / or the actuators of the pneumatic system connected to the device of the invention, no longer deliver their exhaust air at atmospheric pressure (but at a pressure lower than atmospheric pressure), consequently they need less pressure on the supply side; since on the side of their exhausts, the suction facilitates (assists) the accomplishment of the work, this allows a reduction in the instantaneous consumption of compressed air.

[0023] During the operating phase in unstabilized mode or when the turbo pump is unable to admit too large a quantity of exhaust air, the exhaust air collected in the main manifold (and which is at a pressure higher than atmospheric pressure) will exert sufficient pressure to cause the opening of the non-return valve (safety and initialization) leading to the auxiliary manifold in which atmospheric pressure prevails, and will be evacuated there through the exhaust silencers, arranged in sufficient numbers to allow very moderate resistance to flow.

[0024] The device of the invention also allows conventional operation of the installation for tests, troubleshooting, modifications, adjustments and measurements, by simply closing the % turn valves mounted in bypass on the FRL group regulator, and by opening the % turn valve which leads from the main exhaust manifold to the auxiliary manifold and its exhaust silencers. Description of the figures

[0025] The attached drawings illustrate several examples of uses of the invention with a model embodiment of the invention; as well as explanations useful for understanding the operation of the device of the invention.

[0026] [Fig-1] Represents an example of implementation of the device of the invention, on a industrial pneumatic control panel. The device of the invention can be fitted as an additional kit to an FRL group and comprises an exhaust suction turbo pump, the rotation speed of which can be adjusted using a flow adjustment needle valve, manual or piloted (according to an alternative embodiment not shown), and connected to the initial locations of the silencers, on a pneumatic control panel. For better understanding, a representation of the turbo pump (constituting the solution) with its 3 stages is inserted in the illustration (stages 1 and 3 are the turbine part, stage 2 is the pump part) Still for understanding, the piloted venturi (also constituting the invention) is also represented according to a possible embodiment, namely a T-connection with non-return valves.

[0027] [Fig.2] illustrates one of the preferred embodiments of the device, here connected to a tool pneumatic (impact wrench type).

[0028] [Fig.3] illustrates another variant embodiment of the device, here connected with a vacuum gripping assembly (suction cups powered by venturi), this is a case where in principle, the compressed air used does not need to be oiled. However, a semi-closed lubrication loop for the turbo pump (in gripping cases without high air quality requirements) can be achieved; significantly limiting air consumption without unacceptable risk of contamination of the process.

[0029] [Fig.4] illustrates a setpoint adjustment of a spring regulator used in a pneumatic system, for example with a compressed air inlet before the regulator of 6.5 bars to 7 bars for an outlet at the regulator of 6 to 6.2 bars. In the figure, 2 (exaggerated) diaphragm positions have been added, one assumed to be moderate flow and the other to be high flow, and their assumed passage sections (this is to highlight the relationship between the increase in the passage section, with the drop in pressure and flow at the regulator outlet).

[0030] [Fig.5] illustrates a pressure curve as a function of the flow rate at the outlet of a regulator at spring set for a setpoint of 6 bars (which would be supplied with a network pressure of 7 bars). We note that after a certain consumption of compressed air, a continuous and progressive drop in pressure, well below the set value, occurs very quickly. quickly. Thus, when the system consumes a lot of compressed air, the regulator cannot maintain both a high output flow rate and a fixed set pressure, even if the distribution network upstream of the regulator is capable of supplying the required flow rate and pressure for a certain time). Using a larger regulator would not solve the problem, it would transfer it to the distribution network and with lower compressed air consumption by the system a larger regulator would cause more overpressure and shocks at start-up and it will therefore also be necessary to install a larger progressive pressure relief valve to compensate for this.

[0031] [Fig.6] illustrates the same pressure curve as a function of the flow rate at the outlet of a re spring regulator set for a setpoint of 6 bars (which would be supplied with a network pressure of 7 bars) that [Fig.5] But superimposed with the pressure curve as a function of the flow rate of the pneumatic turbo device for recovery and regeneration of residual pneumatic energy from the exhausts, (the dotted line on the graph represents the average pressure value as a function of the flow rate, when the regulator and the turbo pump are combined (in the unblocked state) [Fig.6] also shows the operating steps of the device of the invention; as long as the pressure drop downstream of the regulator is not sufficient to allow, thanks to a sufficient pressure differential, the opening of the non-return valves of the piloted venturi, the turbo pump is not "authorized" (blocked state) to suck the exhaust air from the main manifold. Once the pilot venturi check valves are open, the turbo pump can draw exhaust air from the main manifold, then recycle it and re-pressurize it to around 5 to 5.5 bar relative and re-inject it into the supply line after the regulator.

[0032] With reference to these drawings, the device for recovering and regenerating residual pneumatic energy from the exhausts comprises:

[0033] - A first bypass block placed upstream of the spring regulator (constituting of an FRL group) where a % turn type valve is connected followed by a needle valve for flow adjustment, manual or piloted (according to an alternative embodiment not shown) which supplies the inlets of stages 1 and 3 of the turbo pump.

[0034] - A "compressed air turbo pump for viscous fluid" (the operation of which and the description are detailed in the INPI patent utility certificate 1770207 filing date March 1, 2017 This turbo pump allows the recovery and regeneration of residual pneumatic energy from the exhausts. The inlet of stage 2 (pump part) of the turbo pump is connected via a valve non-return to the exhaust recovery manifold known as the “main” (this collects all the exhausts (except those from the safety components) from a pneumatic system.

[0035] - A second bypass block placed downstream of the regulator where a % turn type valve connected to the outlet of the “piloted” venturi.

[0036] -A “piloted” venturi The inlet of which is connected to the outlet (previously filtered) of stages 1 and 3 (turbine part) of the turbo pump. And whose suction port is connected via a non-return valve to the outlet (previously filtered and separated from liquid water droplets) of stage 2 (pump part) of the turbo pump And finally the outlet port is connected via a non-return valve to the % turn valve leading to the second bypass block.

[0037] - A “main” collector for recovering exhausts (except those of the safety devices) including at least; a non-return valve (safety and initialization), as well as a direct drain % turn valve leading to the “auxiliary” collector.

[0038] - An “auxiliary” collector (equipped with several silencers) capable of receiving air exhaust from the main manifold, coming either from the direct drain % turn valve (in the open position), or from the safety and initialization non-return valve (it allows the system exhausts to be vented to the atmosphere during operation in unstabilized mode or when the turbo pump is unable to admit too large a quantity of exhaust air)

[0039] - One or more coarse separation filters with automatic purge and one or more se water filters with automatic purges, which can be mounted upstream or downstream of the turbo pump.

[0040] According to one of the particular embodiments: - the “piloted” venturi can consist of a T-connector (equal or reduced) whose outlet and suction are equipped with non-return valves allowing the circulation of compressed air in one direction only

[0041] According to the same embodiment, the non-return valves constituting the device can be of the adjustable type.

[0042] Still according to this embodiment, several other conventional T-connections (used as venturis) can be used to recover exhausts which would not be connected to a centralized exhaust.

Claims

Claims

1. A pneumatic turbo device for recovering and regenerating residual pneumatic energy from the exhausts of systems using compressed air, comprising: - A first bypass block placed upstream of a spring regulator constituting a Filter Regulator Lubricator group - A compressed air turbo pump for viscous fluid - A second bypass block placed downstream of the regulator - A controlled venturi - A main exhaust recovery collector - An auxiliary collector equipped with several silencers - One or more coarse separation filters with automatic purges - One or more water separators with automatic purges

2. Device according to claim 1 characterized in that the first bypass block is connected to a % turn type valve followed by a needle valve for flow adjustment, manual or piloted, which supplies the inlets of the turbine stages of the turbo pump.

3. Device according to claim 1 characterized in that the second bypass block is connected to a % turn type valve connected to the output of the piloted venturi.

4. Device according to claim 1 and 3, characterized in that the inlet orifice of the piloted venturi is connected to the pre-filtered outlet of the turbine stages of the turbo pump, and in that the suction orifice of the piloted venturi is connected via a non-return valve to the pre-filtered outlet separated from the liquid water droplets of the pump stage of the turbo pump, and in that the outlet orifice of the piloted venturi is connected via a non-return valve to the % turn valve leading to the second bypass block.

5. Device according to claim 1 characterized in that the main collector for recovering the exhausts except those of the safety organs, comprises at least; a safety and initialization non-return valve as well as a direct drain % turn valve, leading to the auxiliary collector.

6. Device according to claim 5 characterized in that the auxiliary manifold receives the exhaust air from the main manifold, coming either from the direct drain % turn valve in the open position, or from the safety and initialization non-return valve.

7. Device according to any one of the preceding claims, characterized in that the piloted venturi consists of an equal or reduced T-shaped connection, the outlet and suction of which are equipped with non-return valves allowing the circulation of compressed air in one direction only.

8. Device according to claim 7 characterized in that several other conventional T-connectors used as venturis are also used to recover exhausts which would not be connected to a centralized exhaust.

9. Device according to one of claims 4, 5, 6 or 7, characterized in that the non-return valves constituting the device are of the adjustable type.

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