PROPORTIONAL DOSING PUMP
The simplified proportional dosing pump design addresses complexity and cost issues by integrating a compact venturi system with pressure-sensitive means, ensuring precise dosing and efficient operation across varying flow rates.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- DOSATRON INT
- Filing Date
- 2023-12-05
- Publication Date
- 2026-05-15
Smart Images
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Abstract
Description
Title of the invention: PROPORTIONAL DOSING PUMP
[0001] The present invention relates to a method and a proportional dosing pump for introducing a liquid additive into a main liquid stream, flowing in a pipe, the pump being of the reciprocating differential piston type for drawing the additive from a container and dosing it, this pump having a first inlet for receiving a main liquid flow which ensures the drive of a hydraulic machine, a second inlet for drawing the additive and an outlet for the mixture of additive and liquid.
[0002] In a metering pump, the differential piston performs a reciprocating motion and drives a plunger piston to draw the additive to be metered during an upward stroke and to inject this additive into the main fluid or engine fluid during a downward stroke. The pressure drop between the first inlet of the pump and the outlet varies according to the pump's operating phases.
[0003] For good energy efficiency of the pump, it is advantageous, as proposed in the prior art documents EP 1773479 and EP 1151196, to use a venturi to create a pressure loss between its inlet and the throat, substantially equal to the pressure loss in the pump.
[0004] Thus, document WO2014 / 111770 Al proposes to introduce a pressure loss sensitive means in the pump, suitable for controlling the venturi neck throttling means to reduce the passage area when the pressure loss in the pump increases, and to increase the passage area when the pressure loss in the pump decreases.
[0005] However, proportional dosing pumps as modified in document WO2014 / 111770 Al, have a design and manufacture made complex, since it is necessary to add to the pump at least one venturi tube as well as means sensitive to the pressure loss in the pump.
[0006] Therefore, the invention aims, above all, to provide a proportional dosing pump which no longer presents, or presents to a lesser degree, the disadvantages mentioned above and which allows for the simplification of the manufacture and assembly of the pump.
[0007] The invention relates in particular to a proportional dosing pump for an additive in a main liquid, having an inlet and an outlet, and comprising
[0008] - a dosing mechanism provided with means for aspirating an additive stored in a reservoir,
[0009] - a hydraulic machine delimited by a body having an inlet and an outlet connected respectively to the inlet and outlet of the pump, and containing a component designed to perform a reciprocating motion, the pump's power supply main liquid at the inlet triggers the reciprocating movement of the component, which movement alternately causes the additive to be drawn into the hydraulic machine with the suction means opened, then the mixture consisting of the main liquid and the additive to be expelled from the hydraulic machine with the suction means closed.
[0010] - a device for controlling the pressure losses of the pump, as a function of the flow rate at the pump inlet,
[0011] - said device being equipped with a first venturi connected, in parallel with the machine hydraulics, at the pump inlet and outlet
[0012] - said device further comprising a means for closing the neck of the first venturi mounted sliding in said neck to control the passage cross-section, as well as means sensitive to the pressure loss in the pump, suitable for controlling the sliding of the obturating means to reduce the passage cross-section when the pressure loss in the pump increases and / or the flow rate decreases, and to increase the passage cross-section when the pressure loss in the pump decreases and / or the flow rate increases,
[0013] the first venturi being formed inside a first housing at the end of the manufacturing step of said housing, while the pressure loss sensitive means in the pump are mounted in a second housing, the first and second housings as well as the body of the hydraulic machine being assembled together in a compact manner.
[0014] Optional features of the invention, complementary or alternative, are stated below.
[0015] According to a particular embodiment, the means sensitive to the pressure loss in the pump comprise a second venturi installed on a first pipe connecting the inlet of the pump to the inlet of the hydraulic machine, and means for comparing the pressure at the throat of the first venturi, and the pressure at the throat of the second venturi.
[0016] According to a first variant, the second venturi and the first channel are formed at the end of the manufacturing step of the second housing.
[0017] According to a second variant, the second venturi is formed inside a cartridge at the end of the manufacturing step of said cartridge, said cartridge being intended to be inserted into the second housing, through an opening.
[0018] Even more advantageously, the opening is closed by means forming a plug comprising a ring cooperating by screwing with the second housing, and a screw passing through said ring to a stop plane and cooperating by screwing with the cartridge, so that unscrewing the ring causes the removal of the screw and the cartridge assembled to the screw.
[0019] According to a particular configuration, the pressure comparison means comprise a first chamber formed inside the first housing at the end of the manufacturing step of said housing and a second chamber formed inside the second housing at the end of the manufacturing step of said housing, the first chamber being in fluid communication with the neck of the first venturi, and separated hermetically from the second chamber by movable separation means, itself in fluid communication with the neck of the second venturi, the closing means being integral with said movable separation means, so that their deformation causes said closing means to slide along a stroke enabling the passage section of the neck of the first venturi to be enlarged or decreased.
[0020] Preferably, the mobile separation means comprise a membrane.
[0021] Preferably, at least one of the manufacturing steps of the body, respectively of the first casing, of the second casing, of the cartridge is an injection molding step.
[0022] According to a first embodiment, the first housing and the body of the hydraulic machine are produced from a single injection molding step so as to form a single part.
[0023] According to a second embodiment, the second housing and the body of the hydraulic machine are produced from a single injection molding step so as to form a single part.
[0024] Preferably, the injection molding steps use a material selected from polypropylenes, polyamides, polyvinylidene fluorides.
[0025] Even more preferably, the material chosen from among polypropylenes, polyamides, polyvinylidene fluorides, is loaded with reinforcing fibers, and is preferably polypropylene loaded with 30% glass fibers.
[0026] According to one particular feature, the means of obturating is a blade.
[0027] According to another feature, the first and second venturis extend substantially parallel to each other, preferably in a direction substantially perpendicular to the longitudinal axis of the hydraulic machine.
[0028] Other advantages and features of the invention will become apparent upon reading the detailed description of implementations and embodiments, which are by no means limiting, and the following accompanying drawings:
[0029] [Fig. 1] This figure represents a schematic view of a proportional dosing pump according to an embodiment of the invention.
[0030] [Fig.2] This figure represents a longitudinal perspective section of a hydraulic machine used in an embodiment of the invention.
[0031] [Fig.3] This figure represents a cross-section of a proportional dosing pump according to another embodiment of the invention.
[0032] [Fig.4] This figure represents a cross-section of a proportional dosing pump according to yet another embodiment of the invention.
[0033] [Fig.5] This figure represents a cross-section of a proportional dosing pump according to yet another embodiment of the invention.
[0034] [Fig.6] This figure represents a schematic detail of a pump according to a certain embodiment of the invention.
[0035] [Fig.7] This figure represents another schematic detail of a pump according to another embodiment of the invention.
[0036] By referring to [Fig.1] and then to [Fig.2], we can see an example of a hydraulic machine 1 of the type that can be used in the proportional dosing pump according to the invention.
[0037] This example is by no means limiting, since other machines operating on the principle of supplying the pump with main liquid at the inlet triggering the reciprocating movement of a component alternately causing an aspiration of additive, could also be suitable.
[0038] The hydraulic machine 1 comprises a reciprocating differential hydraulic piston 16 contained within a housing 190 consisting of a cylindrical body Cl extending along an axis (z) and surmounted by a cover 191 assembled to the body Cl in a removable manner, notably by screwing. The differential piston 16 is disposed within the housing 190 to slide in reciprocating motion along the axis (z). The piston 16 has, at its upper end, a large-section upper ring 160, the periphery of which bears in a sealed manner against the inner wall of the housing. The piston shaft, coaxial with the housing and of smaller diameter than the upper ring 160, is integral with this ring and extends downwards. The lower part of the piston shaft slides in a sealed manner within a cylindrical housing 17 coaxial with the housing. The shaft is closed at its lower end by a lower base 161.The piston 16 and the cylindrical housing 17 compartmentalize the interior of the casing according to a so-called "mixing" chamber 14 delimited by the cylindrical housing 17 and the lower base of the piston 161, a so-called "upper" chamber 13 delimited by the upper ring 16 and the cover 191 of the casing, and a so-called "lower" chamber 12, of substantially annular shape, delimited by the part below the upper ring 160, by the casing and by the cylindrical housing 17. .
[0039] The hydraulic machine includes a first inlet pipe 10 connecting the lower chamber 12 to the outside, and a second outlet pipe 11 connecting the mixing chamber 14 to the outside. A cylindrical sleeve 15 coaxial with the casing extends downwards from the mixing chamber to allow connection from the mixing chamber to a suction device 2. This suction device is actuated by the hydraulic machine by means of a piston rod 162, itself connected by a nozzle to an additive pumping means (not shown in the figures). For more details concerning this type of device, please refer to documents EP0255791 and EPI 151196.
[0040] Hydraulic switching means are provided for supplying and emptying the chambers 12, 13, 14 separated by the piston. These switching means are controlled by the piston's movements and comprise a connecting rod 180 acting on a distribution member that can assume two stable positions. More specifically, the distribution member comprises at least one valve holder 181 including at least one first valve, referred to as the "upper" valve 182, cooperating with a seat 163 formed in the upper ring of the piston, and at least one second valve, referred to as the "lower" valve 183, cooperating with a seat 164 formed in the lower base of the piston.
[0041] The hydraulic machine further comprises triggering means including a pusher 185 designed to cause, at the end of the piston's stroke, by bearing against a stop, an abrupt change in the position of the switching means under the action of an elastic means 18, for reversing the piston's stroke. Bearing against a stop (not shown in the figures) occurs near the cover 191 to allow the piston to change from an upward stroke to a downward stroke. Bearing against a stop 184 also occurs near the lower part of the casing to allow the piston to change from a downward stroke to an upward stroke.
[0042] The connecting rod 180 is articulated at one end on a fixed point relative to the piston 16, while the other end of the connecting rod can move within a vertical window of the valve carrier 181 and abut against one of the two ends of this window, in one of the two stable positions of the distribution element. The elastic means 18 is fixed, at each of its ends, to a pivoting member received respectively in a housing provided on the connecting rod and on the tappet 185. Each housing is open in a direction substantially opposite to the direction of the force exerted by the elastic means 18 on the wall of the housing in question. This elastic means 18 may advantageously be a convex leaf spring.
[0043] The inlet of the hydraulic machine for the main liquid is located at the level of the first tube 10, and the outlet for the mixture is located at the level of the second tube 11.
[0044] According to the cycle associated with this configuration, the main pressurized liquid, generally water, enters the lower chamber 12 through the tube 10. The upper valves are closed while the lower valves are open, allowing the liquid to be pumped from the upper chamber 13 to the mixing chamber 14 then the evacuation of the mixture towards the outlet via the tube 11. Indeed, under the action of the pressure of the main liquid on the lower face of the upper ring of the piston, the latter begins an upward stroke, which tends to decrease the volume of the upper chamber and therefore to expel its contents towards the mixing chamber, since the communication is open.
[0045] At the end of its upward stroke, the pusher 185 comes to rest against a stop attached to the cover 191, which, under the effect of the elastic means 18, causes the connecting rod 180 to tilt towards the other stable lower position, with the valve carrier moving towards the base of the piston. The lower valves close while the upper valves open. The pressurized liquid can then pass from the lower chamber 12 to the upper chamber 13, whose communication with the mixing chamber 14 is now cut off, and the movement of the piston is reversed. This movement is reversed due to the pressure that the main liquid admitted into the upper chamber exerts on the upper face of the upper ring.At the end of its downward stroke, the pusher 185, at its lower end, encounters a stop 184 fixed to the housing 190. This causes the connecting rod to tilt again towards the raised position and the valve carrier 181 to move, resulting in the closure of the upper valves and the opening of the lower valves. The movement of the piston 16 is reversed again, and the piston resumes its upward stroke.
[0046] Simultaneously, the reciprocating motion of the piston during the supply of liquid to the hydraulic machine allows for the alternate generation of suction through the sleeve 15 into the mixing chamber 14 or at the outlet 11 of the hydraulic machine. The sleeve 15 is connected to the suction device 2, also called the metering mechanism 2, by means of a nozzle.
[0047] As shown in [Fig.2], this dosing mechanism 2, equipped with a suction nozzle fitted with a suction valve, therefore communicates at one of its ends, by means of the sleeve 15, also called the access tube, with an internal cavity in the hydraulic machine and at the other of its ends with a reservoir of product to be dosed.
[0048] The reciprocating motion of the piston 16 during the supply of the main fluid to the hydraulic machine generates suction of the additive, which is injected into the mixing chamber. Generally, the suction device includes at least one suction valve that opens when the piston moves away from the sleeve (i.e., during the upward stroke) and then an expulsion at the outlet via the tube 11 with the first suction valve closing when the piston moves towards the sleeve (i.e., during the downward stroke).
[0049] As shown in figures 2 to 5, the proportional dosing pump according to the invention also includes a device 3 for controlling the pressure losses of the pump, adjustable according to the flow rate at the pump inlet.
[0050] This device 3 is equipped with a first venturi 30 connected, in parallel with the hydraulic machine, to the inlet E and to the outlet of the pump S.
[0051] A venturi is defined as a tube comprising a convergent section, located upstream of a constriction or throat, and a divergent section downstream of the throat. The constriction or throat refers to a region of the venturi, the axial extent of which can be relatively long, and which has a reduced diameter relative to the inlet and outlet diameters. It is at the throat that a low-pressure area is formed, accelerating the liquid.
[0052] The device 3 also includes a means for closing the neck 301 of the first venturi, which is mounted sliding in said neck to control the passage section.
[0053] The device 3 also includes means 31, 33, 35, 36 sensitive to the pressure loss in the pump, adapted to control the sliding of the sealing means to reduce the passage area when the pressure loss in the pump increases and / or the flow rate decreases, and to increase the passage area when the pressure loss in the pump decreases and / or the flow rate increases.
[0054] According to a particular and advantageous embodiment shown in figures 1, 3 to 5, the means sensitive to the pressure loss in the pump comprise a second venturi 31 installed on a first pipe 39 connecting the inlet E of the pump to the inlet of the hydraulic machine, and means for comparing 33, 35, 36 between the pressure at the throat 301 of the first venturi 30, and the pressure at the throat 311 of the second venturi 31.
[0055] In this configuration, the first venturi, equipped with a convergent 300, a throat 301 and a divergent 302, is in fluid communication upstream of its throat 301 with the second venturi 31, by means of the first pipe 39.
[0056] The second venturi 31 is provided with a convergent 310, a throat 311 and a divergent 312, and is connected to the inlet 10 of the hydraulic machine.
[0057] According to a particular and equally advantageous embodiment shown in figures 1, 3 to 5, the pressure comparison means 33, 35, 36 comprise a first chamber 36 and a second chamber 35, the first chamber being in fluid communication with the neck 301 of the first venturi, and separated in a sealed manner from the second chamber 35 by movable separation means 33, itself in fluid communication with the neck 311 of the second venturi.
[0058] The first chamber 36 is in fluid communication with the neck 301 of the first venturi by means, for example, of a conduit 360.
[0059] The second chamber 35 is in fluid communication with the neck 311 of the second venturi by means, for example, of a conduit 350.
[0060] The sealing means 32 is integral with said movable separation means, so that their deformation causes said sealing means to slide along a stroke allowing the passage section of the neck of the first venturi to be enlarged or decreased.
[0061] The sealing means 32 can, for example, have the shape of a thin plate, a cylinder, a half-tube whose convexity is oriented towards the downstream area of the neck of the first venturi.
[0062] The shuttering means 32 can be oriented perpendicular to the geometric axis of the first venturi or inclined.
[0063] The mobile separation means 33 are advantageously a membrane.
[0064] The stroke of the obturating means 32 is defined by the distance between the obturating position (when the means is pushed into the neck of the first venturi) and the position of the obturating means against a shoulder 380, this position being obtained when the pressure in the chamber 36 presses the membrane 33 away from the neck of the first venturi.
[0065] Advantageously, the first and second venturis extend in a substantially parallel manner to each other, thus allowing good compactness of the device 3.
[0066] Even more advantageously, the first and second venturis extend substantially parallel to each other along the direction (y) perpendicular to the longitudinal axis (z) of the hydraulic machine.
[0067] Regarding the operation of the pump, when the pump is at rest, i.e. when it is not in operation, the sealing means 32 seals the neck 301 of the venturi 30, so that the passage area of the neck 301 is less than 5 mm2, or even zero.
[0068] When the hydraulic machine is first supplied with main fluid, the main fluid stream arrives at the inlet E of the pump and does not flow or flows very little through the neck 301 of the first venturi.
[0069] The main liquid, which flows mainly through the second venturi 31, operates the hydraulic machine 1 by actuating the differential piston 16 using almost all of the main flow diverted by the second venturi 31 and the first pipe 39.
[0070] The dosing mechanism 2 driven by the reciprocating movements of the differential piston 16 draws doses of additive from the container and the dosed mixture is injected downstream 302 of the venturi neck through the line 11 towards the outlet S of the pump.
[0071] When the flow rate of the main liquid arriving at the inlet E of the pump increases, the pressure in the chamber 35 decreases and deforms the diaphragm 33 which rises and reduces the volume of the chamber 35.
[0072] This results in the translation of the obturating means 32. The latter no longer obturates the neck 301 of the venturi 30 and the main liquid can then flow through the neck 301 of the first venturi.
[0073] The main liquid can then flow through the pipe 360.
[0074] At the col 301 of the venturi 30, the fluid flow velocity increases and its static pressure decreases.
[0075] At the neck 311 of the venturi 31, the fluid flow velocity decreases and its static pressure increases.
[0076] When the pump is supplied with a determined inlet flow E, the differential piston 16 operates using a fraction of the main flow derived by the second venturi 31 and the first channel 39.
[0077] The dosing mechanism 2 driven by the reciprocating movements of the differential piston 16 draws doses of additive from the container and the dosed mixture is injected downstream 302 of the venturi neck through the line 11 towards the outlet S of the pump.
[0078] During the upward movement of the differential piston 16 and the plunger piston of the metering mechanism 2, the pressure loss between the inlet 10 and the outlet 11 of the hydraulic machine is greater than during the downward movement.
[0079] The increase in pressure loss on the ascent causes a decrease in the flow passing through the hydraulic machine, and therefore through the neck 311 of the venturi 31, which results in an increase in pressure at the neck 311.
[0080] The pressure at the neck 311 of the second venturi 31 therefore increases relative to that prevailing at the neck of the first venturi 301.
[0081] Under these conditions, the pressure in chamber 35 becomes greater than that in chamber 36 and the diaphragm 33 deforms to allow the sealing means 32 to slide and enter further into the throat of the venturi 301. This results in an increase in the pressure loss between the inlet (convergent 300) and the outlet (divergent 302) of the venturi 30, which makes it possible to equalize the pressure loss at the throat of the venturi 30 and the pressure loss between the inlet 10 and the outlet 11 of the hydraulic machine 1, or at least to minimize the difference between these pressure losses, which helps to improve the dosing accuracy.
[0082] During the descent of the differential piston 16 and the plunger piston of the metering mechanism 2, the pressure loss between the inlet 10 and the outlet 11 of the hydraulic machine 1 is lower, so that the sealing means 32 rises in the chamber 36 and reduces the constriction of the venturi neck 301 and therefore the pressure loss between the inlet (convergent 300) and the outlet (divergent 302) of the venturi 30.
[0083] Thus, for high flow rates, the sealing means 32 and the diaphragm 33 will oscillate at the speed of the differential piston 16 to ensure a better fit between the pressure loss at the venturi throat 30 and the total pressure loss in the hydraulic machine 1.
[0084] For small flow rates, the working range of the device is made reliable with precise dosing and good operating efficiency, insofar as the Venturi effect is controlled at the neck 301 of the first venturi 30.
[0085] In other words, since at low flow rates the pressure losses are not negligible, the final dosage would be much too high if all the engine fluid passed through the metering device due to complete occlusion by means 32, which would be due to a very marked Venturi effect.
[0086] In summary, the total pressure loss in the hydraulic machine 1 is compensated by the pressure loss at the venturi throat 30 accurately for both high and low flow rates.
[0087] As shown in Figures 1, 3 to 5 and in accordance with the principle of the invention, the first venturi 30 is formed inside a first housing C30 at the end of manufacturing step E30 of said housing, while the pressure-sensing means 31, 33, 35, 36 in the pump are contained in a second housing C32. The first and second housings 30, 32, as well as the body Cl of the hydraulic machine, are assembled together in a compact manner. "Assembled together" means that the first and second housings 30, 32, as well as the body Cl of the hydraulic machine, are fixed against each other without requiring flexible connections to allow fluid circulation. The first and second housings 30, 32, and the body Cl of the hydraulic machine thus form a single, compact unit.
[0088] In other words, the internal volume of the first venturi 30 is defined by a recess made inside the first C30 housing, this recess being obtained directly at the end of the manufacturing step of the C30 housing.
[0089] In the example illustrated in the figures, the pressure-sensitive means in the pump comprise a second venturi 31 installed on a first pipe 39 connecting the inlet E of the pump to the inlet of the hydraulic machine, and comparison means 33, 35, 36 between the pressure at the throat 301 of the first venturi 30, and the pressure at the throat 311 of the second venturi 31
[0090] According to the principle of the invention, the chambers 35 and 36, as well as the membrane 33 which separates the chambers, are provided in a cavity of the second housing C32 which opens out of the second housing C32 into the first housing C30. This cavity is also obtained directly at the end of the manufacturing step of the housing C32.
[0091] Just like the first venturi 30, the internal volume of the second venturi 31, as well as the channel 39, can be defined by a recess formed inside the second C32 case, this hollowing being obtained directly at the end of the manufacturing stage of the C32 case.
[0092] According to an advantageous alternative, the second venturi 31 is formed inside a cartridge C31 at the end of the manufacturing step E31 of said cartridge. In this case, said cartridge C31 is intended to be inserted into the second housing C32, through an opening C320, obtained directly at the end of the manufacturing step of the housing C32.
[0093] This allows the dimensions of the second venturi to be adapted to the flow and dosing parameters of the pump, simply by changing the cartridge. More specifically, the lower the desired dosages, the smaller the neck 311 of the second venturi 31 is, so as to increase the division of the second venturi, that is to say, the ratio between the neck 311 of the second venturi 31 and the neck 301 of the first venturi 30.
[0094] As shown in [Fig.6], the opening C320 is advantageously closed, after insertion of the cartridge with plugging means 4 comprising a ring 40 and a screw 41.
[0095] The ring 40 cooperates in screwing (or according to a bayonet mounting) with the second housing C32, while the screw 41 passes through said ring to a stop plane 42 to cooperate in screwing (or according to a bayonet mounting) with the cartridge C31.
[0096] Thus, to mount the cartridge C31 in the second housing C32, the cartridge is first inserted into the opening C320 of the second housing. Then the ring 40 is screwed onto the second housing C32. Next, the screw 41 is screwed into the cartridge C31 until the screw comes to a stop 42 against the ring.
[0097] Alternatively, the cartridge C31 can be mounted in the second housing C32 by first attaching the screw 41 to the cartridge C31 and sandwiching the ring 40 between them. Then, the assembly is screwed to the second housing C32. This provides a grip for correctly orienting the cartridge within the second housing C32.
[0098] To disassemble the cartridge C31, the ring 40 is first unscrewed from the second housing C32. The stop plane 42 then moves the screw 41 and also the cartridge, which can thus be extracted from the second housing C32.
[0099] All that remains is to unscrew the screw 41 from the cartridge C31.
[0100] Preferably, at least one, and preferably all, of the manufacturing steps El of the body Cl, E30 of the first casing C30, E32 of the second casing C32, E31 of the cartridge C31 is an injection molding step.
[0101] According to an advantageous embodiment, the first housing C30 and the body Cl of the hydraulic machine are produced from a single injection molding step El30 so as to form a single part.
[0102] According to an equally advantageous alternative, the second housing C32 and the body Cl of the hydraulic machine are produced in a single injection molding step E132 so as to form a single part. As shown in [Fig. 7], the first housing C30 then includes an angled portion C300 which allows the outlet 11 of the hydraulic machine to be connected to the downstream portion of the first venturi.
[0103] Preferably, the injection molding steps use a material selected from polypropylenes, polyamides, polyvinylidene fluorides.
[0104] Even more preferably, the material chosen from among polypropylenes, polyamides, polyvinylidene fluorides, is loaded with reinforcing fibers, and is preferably polypropylene loaded with 30% glass fibers.
[0105] Thus, the proportional dosing pump according to the invention has a simplified design and assembly.
[0106] The assembly operations include first of all the assembly of the parts contributing to the reciprocating motion in the body Cl.
[0107] Then the membrane 33 and the shuttering means 32 are mounted on the second housing C32. The membrane can advantageously be overmolded onto the shuttering means 32.
[0108] Next, the first C30 and second C32 housings are assembled in pairs, along with the body Cl of the machine, by screwing or other equivalent operation.
[0109] In the case where the body of the hydraulic machine forms only one and the same piece with the first or second housing, it is simply required to assemble the first housing with the second housing.
[0110] The sealing of the device is ensured by a set of seals 37 which are positioned during the assembly of the various components of the pump.
[0111] Advantageously, the first and second housings extend substantially parallel to each other, and preferably in a direction (y) perpendicular to the longitudinal axis (z) of the hydraulic machine, to allow for good compactness of the pump.
[0112] It appears that the design of the proportional dosing pump is simplified and more compact than that presented in document WO2014 / 111770 Al which required at least a first mounting support for the first venturi, a second mounting support for the hydraulic machine and two pipes to connect the first venturi to the hydraulic machine.
[0113] The use of injection molding also makes it possible to obtain the housings and the body of the hydraulic machine directly and to minimize the number of parts.
[0114] Note that the different characteristics, forms, variants and embodiments of the invention can be associated with each other, according to various combinations insofar as they are not incompatible or exclusive of each other.
Claims
1. Demands A proportional dosing pump for an additive in a main liquid, having an inlet (E) and an outlet (S), and comprising - a dosing mechanism (2) equipped with means for drawing up an additive stored in a reservoir, - a hydraulic machine (1) delimited by a body (Cl) having an inlet (10) and an outlet (11) connected respectively to the inlet and outlet of the pump, and containing a component (16) adapted to perform a reciprocating motion, the supply of the pump with main liquid at the inlet triggering the reciprocating motion of the component (16), which motion alternately causing the additive to be drawn into the hydraulic machine with the opening of the suction means and then expelled from the outlet (11) of the hydraulic machine with the closing of the suction means, - a device (3) for controlling the pressure losses of the pump, as a function of the flow rate at the pump inlet, - said device (3) being equipped with a first venturi (30) connected, in parallel with the hydraulic machine, to the inlet and outlet of the pump - said device (3) further comprising a means for closing the neck (301) of the first venturi mounted sliding in said neck to control its passage area, as well as means (31, 33, 35, 36) sensitive to the pressure loss in the pump, adapted to control the sliding of the closing means to reduce the passage area when the pressure loss in the pump increases and / or the flow rate decreases, and to increase the passage area when the pressure loss in the pump decreases and / or the flow rate increases, - characterized in that the first venturi (30) is formed inside a first housing (C30) at the end of the manufacturing step (E30) of said housing, the internal volume of the first venturi (30) being defined by a recess formed inside the first housing (C30), this recess being obtained directly at the end of the manufacturing step (E30) of the housing (C30), while the means (31, 33, 35, 36) sensitive to the pressure drop in the pump are mounted in a second housing (C32), the first and second housings (C30, C32) thus that the body (Cl) of the hydraulic machine being fixed against each other, without requiring flexible type fittings to allow fluid circulation, so that they thus assembled form a compact block of one piece.
2. Proportional dosing pump according to the preceding claim, characterized in that the pressure loss sensitive means in the pump comprise a second venturi (31) installed on a first pipe (39) connecting the inlet (E) of the pump to the inlet of the hydraulic machine, and comparison means (33, 35, 36) between the pressure at the throat (301) of the first venturi (30), and the pressure at the throat (311) of the second venturi (31).
3. Proportional dosing pump according to the preceding claim, characterized in that the second venturi (31) and the first channel (39) are formed at the end of the manufacturing step (E32) of the second casing (C32).
4. Proportional dosing pump according to claim 2, characterized in that the second venturi (31) is formed inside a cartridge (C31) at the end of the manufacturing step (E31) of said cartridge, said cartridge (C31) being intended to be inserted into the second housing (C32), through an opening (C320).
5. Proportional dosing pump according to the preceding claim, characterized in that the opening (C320) is closed by plugging means (4) comprising a ring (40) cooperating by screwing with the second housing (C32), and a screw (41) passing through said ring to a stop plane (42) and cooperating by screwing with the cartridge (C31), so that unscrewing the ring causes the removal of the screw and the cartridge assembled to the screw.
6. Proportional dosing pump according to any one of claims 2 to 5, characterized in that the pressure comparison means (33, 35, 36) comprise a first chamber (36) formed inside the first housing (C30) at the end of the manufacturing step (E30) of said housing and a second chamber (35) formed inside the second housing (C32) at the end of the manufacturing step (E32) of said housing, the first chamber being in fluid communication with the neck (301) of the first venturi, and hermetically separated from the second chamber (35) by movable separation means (33), itself in fluid communication with the neck (311) of the second venturi, the closing means (32) being integral with said movable separation means, so that their deformation causes the said sealing means to slide along a stroke allowing the passage section of the neck of the first venturi to be enlarged or decreased.
7. Proportional dosing pump according to the preceding claim, characterized in that the movable separation means (33) comprise a membrane.
8. Proportional dosing pump according to any one of the preceding claims, characterized in that at least one of the manufacturing steps (El) of the body (Cl), respectively (E30) of the first housing (C30), (E32) of the second housing (C32), (E31) of the cartridge is an injection molding step.
9. Proportional dosing pump according to claim 8, characterized in that the first casing (C30) and the body (Cl) of the hydraulic machine are produced from a single injection molding step (El30) so as to form a single piece.
10. Proportional dosing pump according to claim 8, characterized in that the second casing (C32) and the body (Cl) of the hydraulic machine are produced from a single injection molding step (El32) so as to form a single piece.
11. Proportional dosing pump according to any one of claims 8 to 10, characterized in that the injection molding steps use a material selected from polypropylenes, polyamides, polyvinylidene fluorides.
12. Proportional dosing pump according to the preceding claim, characterized in that the material chosen from polypropylenes, polyamides, polyvinylidene fluorides, is loaded with reinforcing fibers, and is preferably polypropylene loaded with 30% glass fibers.
13. Proportional dosing pump according to any one of the preceding claims, characterized in that the sealing means (32) is a blade.
14. Proportional metering pump according to any one of the preceding claims, together with claim 2, characterized in that the first and second venturis extend substantially parallel to each other, preferably in a direction substantially perpendicular to the longitudinal axis (z) of the hydraulic machine.