Pumping apparatus

Abstract

Pumping apparatus (3) comprising a first fluid machine (3A) and a second fluid machine (3B) each comprising a piston (4) and a guide (5) delimiting a first chamber (61) for compression and expansion of a fluid, the piston (4) and the guide (5) being movable relative to each other for the compression and expansion of the fluid in the first chamber (61), the first fluid machine (3A) and the second fluid machine (3B) each also comprising a sealing device (7) disposed between the piston (4) and the guide (5), characterized in that it comprises a collection element (8) configured to collect at least a part of the leaks which have migrated through the sealing device (7) of one of the machines (3A, 3B) and to direct these collected leaks into the first chamber (61) of the other of the fluid machines (3A, 3B).

Description

[0001] The invention relates to a pumping apparatus comprising fluid machines and a leak collection device for transferring fluid from one machine to another. Specifically, it relates to volumetric fluid machines (pump, compressor) for a cryogenic fluid. The fluid in question may be hydrogen.

[0002] The invention also relates to a compressor or a pump comprising such a pumping device.

[0003] A fluid machine includes, for example, a tubular piston, a fixed guide located inside the tubular piston, a chamber delimited by the piston and the guide, and a set of seal(s) arranged between the piston and the guide. The piston and the guide are configured to move back and forth between a fluid intake configuration in the chamber and a fluid compression configuration in the chamber.

[0004] Despite recent advances in fluid machine design, ensuring the airtightness of the chamber defined by the piston and guide remains difficult, particularly during fluid compression. Specifically, as the seals wear, a path or passage develops between them and the piston, resulting in leakage from the chamber.

[0005] This leakage flow can be vented or returned to a source that feeds the fluid machine (in the case of a compressor or pump). This leakage flow therefore constitutes a loss of material that affects the volumetric efficiency of the fluid machine and consequently the discharge rate. Furthermore, when the leakage flow is returned to the source that feeds the fluid machine, this flow expands and generates heat in the source. This results in evaporation (Boil of Gas - BOG) of the fluid in the source.

[0006] Whether vented or returned to the fluid machine's power supply, the leakage flow is not sufficiently utilized. One aim of the invention is to remedy this drawback.

[0007] In this regard, according to a first aspect, the invention relates to a pumping device.

[0008] The pumping apparatus comprises a first fluid machine and a second fluid machine, each comprising a piston and a guide defining a first chamber for the compression and expansion of a fluid. The piston and the guide are movable relative to each other for the compression and expansion of the fluid in the first chamber. Both the first and second fluid machines also each include a sealing device disposed between the piston and the guide.

[0009] According to this first aspect of the invention, the pumping apparatus includes a collection element configured to collect at least part of the leaks that have migrated through the sealing device of one of the fluid machines and direct these collected leaks into the first chamber of the other of the fluid machines.

[0010] Embodiments according to the first aspect of the invention may include one or more of the following features: The first fluid machine and the second fluid machine are configured to operate in an antagonistic mode, i.e., an expansion configuration in the first fluid machine coincides with a compression configuration in the second fluid machine, and vice versa. The first fluid machine and the second fluid machine each include at least one leakage path between the sealing device and the piston. The collecting element has a first end in fluidic communication with the leakage path of one of the fluid machines and a second end in communication with the first compression chamber of the other fluid machine. The collecting element further includes, at the level of one of the fluid machines, a first non-return valve configured to control the fluidic circulation between the collecting element and the leakage path of said machine.The collection unit also includes, at the level of the other fluid machine, a second non-return valve configured to control fluid circulation between the collection unit and the first compression chamber of said fluid machine; the apparatus includes a venting conduit connected to the collection unit and configured to discharge a portion of the collected leakage flow outside the fluid machines; the sealing device includes a set of O-rings arranged in housings provided between the piston and the guide; each fluid machine includes a fluid inlet system for the first chamber; each fluid machine includes a compressed fluid discharge system from the first expansion and compression chamber; at least one of the fluid machines includes a second expansion and compression chamber delimited by the piston and / or the guide and a cylinder.The second chamber is connected to the first chamber via a transfer system. The fluid machine is of the two-stage compression type, meaning that the fluid is first admitted into the second chamber where it is compressed once, then transferred back into the first chamber via the transfer system to be compressed a second time. The piston or guide is configured to move in reciprocating relative motion with respect to the cylinder. The collection device is configured to transfer at least some of the leakage that has migrated through the sealing device of one of the fluid machines to the first compression chamber of the other fluid machine.

[0011] According to a second aspect, the invention relates to a compressor or pump, in particular for cryogenic fluid such as hydrogen, the compressor or pump comprising a pumping device according to any one of the embodiments described above.

[0012] Other features and advantages will become apparent upon reading the description below, which refers to the following figures in which: [ Fig. 1 ] is a schematic view illustrating a pump according to a first embodiment of the invention, the pump comprising a pumping apparatus including a first fluid machine, a second fluid machine, and a collection element for collecting leaks from one machine to the other, each machine including a piston and a guide delimiting a first chamber. Fig. 2 ] is a schematic cross-sectional view illustrating the pump of the [ Fig. 1 ] in a second configuration. [ Fig. 3 ] is a schematic cross-sectional view illustrating the pump of the [ Fig. 1 ] in a third configuration. [ Fig. 4 ] is a schematic cross-sectional view illustrating the pump of the [ Fig. 1 in a fourth configuration. Fig. 5 [ ] is a schematic view illustrating a pump according to a second embodiment of the invention, in which each fluid machine further comprises a cylinder containing the piston, the cylinder and piston delimiting a second chamber. Fig. 6 ] is a schematic view of the pump of the [ Fig. 5 ] in a second configuration. [ Fig. 7 ] is a schematic view of the pump of the [ Fig. 5 ] in a third configuration. [ Fig. 8 ] is a schematic view of the pump of the [ Fig. 5 in a fourth configuration. Fig. 9 ] is a schematic view of a variant of the pump illustrated in the [ Fig. 5 ], the pumping apparatus comprising a first collection element connecting the first chamber of the first fluid machine to the second chamber of the second fluid machine, and a second collection element connecting the first chamber of the second fluid machine to the second chamber of the first fluid machine. Fig. 10 ] is a schematic view of the pump of the [ Fig. 9 ] in a second configuration. [ Fig. 11 ] is a schematic view of the pump of the [ Fig. 9 ] in a third configuration. [ Fig. 12 ] is a schematic view of the pump of the [ Fig. 9 in a fourth configuration. Fig. 13 ] illustrates examples of the arrangement between discharge ports and transfer ports in one of the fluid machines illustrated in the [ Fig. 1 ]. THE [Fig. 1] à [Fig. 12] illustrate a pump or compressor 100 intended to supply a system (not shown) with pressurized cryogenic fluid.

[0013] Pump 100 comprises a storage tank 1 for a fluid 2 and a pumping apparatus 3 including a plurality of fluid machines 3A, 3B arranged in the tank 1. The fluid machines 3A, 3B are immersed in the fluid 2 to pump it for compression. The tank 1 can be thermally insulated, particularly when it contains a liquefied cryogenic fluid.

[0014] In the illustrated examples, the compressor or pump 100 comprises two fluid machines: a first fluid machine 3A and a second fluid machine 3B.

[0015] Each fluid machine 3A, 3B comprises a piston 4, a guide 5 disposed inside the piston 4, a first chamber 61 delimited by the piston 4 and the guide 5, and a sealing device 7 disposed between the piston 4 and the guide 5. In particular, the piston 4 and the guide 5 are configured to be in translational motion relative to each other between a fluid admission configuration in the first chamber 61 and a fluid compression configuration in the first chamber 61. As shown in the figures, the piston 4 is tubular and is threaded onto the guide 5.

[0016] The first fluid machine 3A and the second fluid machine 3B are distinct and independent, as shown. That is, the first fluid machine 3A and the second fluid machine 3B each comprise a separate piston-guide assembly and can each be operated independently. For example, the reciprocating movements of the pistons are independent and controlled by each other.

[0017] In the illustrated example, the first fluid machine 3A and the second fluid machine 3B are configured to operate in an antagonistic (offset or phase-shifted) mode, i.e. the inlet configuration in the first fluid machine 3A coincides with the discharge configuration in the second fluid machine 3B and vice versa.

[0018] Furthermore, the piston 4 and the guide 5 are cylindrical in shape. More specifically, the piston 4 may include a circumference 41, a first base 42, and a second base 43 opposite the first base 42 with respect to the circumference 41. Similarly, the guide 5 includes a periphery 51, a first end 52, and a second end 53 opposite the first end 52 with respect to the periphery 51. The first end 52 of the guide 5 is opposite the first base 42 of the piston 4.

[0019] Thus, in each fluid machine 3A, 3B, the first chamber 61 is delimited by the first end 52 of the guide 5 as well as by the perimeter 41 and the first base 42 of the piston 4.

[0020] The first chamber 61 thus delimited is in fluidic communication with the volume of the reservoir 1 of the pump 100 through a first inlet system. In addition, the first chamber 61 is in fluidic communication with the outside of the pump 100 (for example, a system intended to be supplied by the compressor or the pump 100) through a first discharge system.

[0021] In other words, the first inlet system of each pump 100 is configured to put each first chamber 61 into fluidic communication with the volume of the reservoir 1 of the pump 100. Thus, each first chamber is configured to be supplied with fluid at the same pressure, here equal to the pressure that reigns in the reservoir 1 of the pump 100.

[0022] The first intake system includes at least one first intake port 44. This port is equipped with a first intake valve 44a intended to fluidly connect the first chamber 61 and the volume of the reservoir 1 of the pump 100. In the illustrated example, the first intake port(s) 44 are formed at the first base 42 of the piston 4.

[0023] The first discharge system includes at least one first discharge orifice 54 which allows the compressed fluid in chamber 61 to be evacuated from that chamber. Each of the first discharge orifice(s) 54 is or are equipped with a first discharge valve 54a. In the illustrated example, the first discharge orifice(s) 54 are formed at the first end 52 of the guide 5.

[0024] In order to convey the compressed fluid out of the pump 100, the first discharge system of each fluid machine 3A, 3B preferably includes at least one discharge conduit 55.

[0025] In each fluid machine 3A, 3B, the discharge conduit(s) 55 extend inside the guide 5 from the first discharge port 54. Furthermore, the discharge conduit(s) 55 exit the machine 3A, 3B through the second end 53 of the guide 5.

[0026] In the illustrated example, each fluid machine 3A, 3B includes a single discharge conduit 55 extending from the first discharge orifice 54 formed at the first end 52 of the guide 5.

[0027] In an unillustrated variant, each fluid machine 3A, 3B comprises two discharge conduits 55 extending respectively from two first discharge ports 54 formed at the first end 52 of the guide 5. These two discharge conduits 55 join into a single conduit outside the fluid machine 3A, 3B.

[0028] The sealing device 7 comprises a plurality of sealing gaskets. To allow the mounting of these sealing gaskets 7 on each fluid-filled machine 3A, 3B, the periphery 51 of the guide 5 may include slots that form annular grooves. The sealing gaskets 7 are thus arranged in these grooves and are configured to come into radial contact with an inner face of the circumference 41 of the piston 4.

[0029] Due to the relative movement between the piston 4 and the guide 5, the seals 7 mounted on the guide 5 are also in relative movement with respect to the piston 4. The seals 7 are called dynamic seals.

[0030] In the illustrated example, the sealing gaskets 7 are distributed in two longitudinal series: a first series located near the first end 52 of the guide 5 (at the bottom when the machine 3A, 3B is arranged vertically in the operating configuration), and a second series located near the second end 53 of the guide 5 (at the top when the machine 3A, 3B is arranged vertically in the operating configuration).

[0031] Advantageously, the 7 joints of the first series have a different coefficient of thermal expansion than the 7 joints of the second series.

[0032] During the life cycle of the pump 100, the seals 7 and the inner wall of the piston 4's outer ring 41 are not always arranged in a tight fit. Furthermore, as the seals 7 wear, at least one path or passage forms between these seals 7 and the inner face of the piston 4's outer ring 41. Part of the fluid admitted and then compressed in the first chamber 61 can then escape from this first chamber 61 via one of these paths.

[0033] This lost portion of the fluid is subsequently referred to as "leaks" or "leakage flow". The path formed by the sealing rings 7 and the inner face of the piston 4's circumference 41, and through which the leaks pass, is subsequently referred to as the "leakage path".

[0034] To make advantageous use of the leaks produced by the fluid machines 3A, 3B, the invention introduces a collection element 8 configured to recover a leakage flow from any one of these fluid machines 3A, 3B and transfer said flow to any other of these fluid machines 3A, 3B.

[0035] More specifically, the collection element 8 is configured to recover a leakage flow from one or more leakage paths present in any one of the fluid machines 3A, 3B and transfer this leakage flow to the first chamber 61 of the other fluid machine 3A, 3B. In other words, the collection element 8 has a first end in fluidic communication with the leakage path of one of the fluid machines 3A, 3B and a second end in fluidic communication with the first compression chamber 61 of the other fluid machine 3A, 3B.

[0036] The collection device 8 is therefore configured to recover a leakage flow produced at the outlet or at the level of the first chamber 61 of any one of the fluid machines 3A, 3B and transfer it to the first chamber 61 of the other of the fluid machines 3A, 3B. That is to say, the leakage flow is transferred to a first chamber 61 operating at the same inlet pressure as the other first chamber 61.

[0037] Thanks to the collection element 8 and the complete or partial recycling of leaks it enables, the invention significantly increases the efficiency of the pump 100 and reduces its operating costs. Furthermore, thanks to the collection element 8, the discharge flow rate of the pump 100 remains relatively stable, even in the event of wear on the seals 7, as long as it remains possible to recover and recycle the leaks. Finally, thanks to the collection element 8, the invention makes it possible to reduce or maintain low BOG levels, thus reducing the frequency of maintenance operations on the pump 100.

[0038] In the illustrated example, the collection device 8 is configured to collect a first leakage flow from the leakage path(s) of the first fluid machine 3A and transfer this first flow to the first chamber 61 of the second fluid machine 3B. Similarly, the collection device 8 is configured to collect a second leakage flow from the leakage path(s) of the second fluid machine 3B and transfer this second flow to the first chamber 61 of the first fluid machine 3A.

[0039] To achieve this, the collection unit 8 includes a main conduit 81 which extends between the first fluid machine 3A and the second fluid machine 3B. In particular, the main conduit 81 extends between the first chamber of one of the fluid machines 3A, 3B and the first chamber of the other of the fluid machines 3A, 3B.

[0040] In addition, the collection organ 8 includes at the level of each machine 3A, 3B with fluid at least one secondary conduit 82 which has a first end connected to the main conduit 81 and a second end disposed through a lateral opening 57 (gap, volume or other) formed between the piston 4 and the guide 5.

[0041] This lateral opening 57 is formed, for example, at a notch on the periphery 51 of the guide 5, preferably between the two sets of sealing gaskets 7. Furthermore, this lateral opening 57 forms a point through which the leakage path(s) of the fluid machine 3A, 3B open into the collection element 8. Finally, this lateral opening 57 is preferably equipped with a collection valve 57a intended to fluidly connect or isolate the collection element 8 from the leakage path(s) of the fluid machine 3A, 3B. Advantageously, this collection valve 57 can be a one-way check valve.

[0042] At each fluid machine 3A, 3B, the main conduit 81 opens into the first chamber 61 through an injection orifice 56. This is preferably equipped with a valve 56a, for example a non-return valve, intended to connect fluidly and unidirectionally the collection element 8 and the first chamber 61 of the machine 3A, 3B concerned.

[0043] Advantageously, the injection orifice 56 of each fluid machine 3A, 3B is formed at the first end 52 of the guide 5, which delimits the first chamber 61 of the fluid machine 3A, 3B considered.

[0044] It should be noted that the main conduit 81 comprises, at each fluid machine 3A, 3B, a portion extending inside said fluid machine 3A, 3B, and a portion extending outside the fluid machines 3A, 3B. In order to limit evaporation of any leakage flux through the portion of the main conduit 81 extending outside the fluid machines 3A, 3B, the collection element 8 is advantageously equipped with a cooling system (not shown).

[0045] It should also be noted that in each fluid machine 3A, 3B, the first end 52 of the guide 5 carries both the discharge port(s) 54 and the injection port(s) 56. Different arrangements of the injection ports 56 and discharge ports 54 can be considered at the first end 52 of the guide 5, depending on their respective numbers. The [ Fig. 13 ] illustrates some examples of arrangements between discharge ports 54 and injection ports 56 at the first end 52 of the guide 5.

[0046] In a first example (a), the first end 52 of the guide 5 has a single first discharge port 54 and a single injection port 56. The two ports 54, 56 are located along a diameter of the first end 52 of the guide 5. The two ports 54, 56 are located equidistant from the center of the first end 52 of the guide 5.

[0047] In a second example (b), the first end 52 of the guide 5 has a single injection port 56 and two discharge ports 54. The injection port 56 is located in the center of the end 52 of the guide 5 between the two discharge ports 54.

[0048] In a third example (c), the first end 52 of the guide 5 has a single injection port 56 and three discharge ports 54. The injection port 56 is located in the center of the end 52 of the guide 5. The discharge ports 54 are arranged around the injection port 56 at regular intervals.

[0049] Advantageously, the pumping unit 3 includes a discharge conduit 83 connected to the collection unit 8. The discharge conduit 83 is configured to discharge a portion of the leakage flow collected by the collection unit 8 away from the fluid-filled machines 3A and 3B, particularly when the collected leakage flow rate is very high. The discharge conduit 83 can be equipped with a flow meter whose measurement can provide information on the wear of the seals 7.

[0050] THE [Fig. 1] à [Fig. 4] illustrate a pump operating cycle 100.

[0051] In a configuration illustrated in the [ Fig. 1 ], the first fluid machine 3A is at the end of the admission of a flow of fluid 2 contained in the tank 1 while the second fluid machine 3B is at the end of the compression of the fluid, at the end of the discharge of the compressed fluid to the outside, and at the end of the transfer of leaks to the first chamber 61 of the first machine 3A.

[0052] At the first fluid machine 3A, the first inlet valve 44a and the injection valve 56a are open, while the collection valves 57a and the discharge valve 54a are closed. At the second fluid machine 3B, the first inlet valve 44a and the injection valve 56a are closed, while the collection valves 57a and the discharge valve 54a are open.

[0053] In a configuration illustrated in the [ Fig. 2 The first fluid machine 3A is in the compression phase, and the component 8 then collects the leaks from the first fluid machine 3A and transfers them to the first chamber 61 of the second fluid machine 3B. The second fluid machine 3B is at the end of the admission of a flow of fluid 2 contained in the reservoir 1.

[0054] At the first fluid machine 3A, the first inlet valve 44a, the injection valve 56a, and the discharge valve 54a are closed, while the collection valves 57a are open. At the second fluid machine 3B, the collection valves 57a and the discharge valve 54a are closed, while the injection valve 56a is open.

[0055] In a configuration illustrated at [ Fig. 3 The first fluid machine 3A is in the fluid compression and discharge phase. Component 8 collects a leakage stream from the first machine 3A and transfers it to the second machine 3B. The second fluid machine 3B is in the intake phase of a fluid stream 2 from reservoir 1 and is mixing this stream with the leakage stream received from the collection component 8.

[0056] At the first fluid-filled machine 3A, the first inlet valve 44a and the injection valve 56a remain closed, while the collection valves 57a and the discharge valve 54a are open. At the second fluid-filled machine 3B, the injection valve 56a and the first inlet valve 44a remain open, while the collection valves 57a and the discharge valve 54a remain closed.

[0057] Finally, in a configuration illustrated in the [ Fig. 4 The first fluid machine 3A is in the final stages of compression and discharge of the compressed fluid to the outside. Element 8 collects a leakage flow from the first machine 3A to the second fluid machine 3B. The second fluid machine 3B is in the final stages of receiving a flow of fluid 2 from reservoir 1, and of mixing this flow with the leakage flow received from the collection element 8.

[0058] At the first fluid-filled machine 3A, the first inlet valve 44a and the injection valve 56a remain closed, while the collection valves 57a and the discharge valve 54a remain open. At the second fluid-filled machine 3B, the injection valve 56a and the first inlet valve 44a remain open. The collection valves 57a and the discharge valve 54a remain closed.

[0059] The first fluid machine 3A and the second fluid machine 3B can therefore be configured to work in opposite phase, and the leak collection device 8 is configured to recover the leaks produced by one of the machines 3A, 3B, which is then in the compression phase, and inject them into the other fluid machine 3A, 3B, which is then in the admission phase.

[0060] With reference to [Fig. 5] à [Fig. 12] We now describe a second embodiment of the invention.

[0061] This second mode retains the characteristics of the first mode described above. One difference lies in the fact that each fluid-filled machine 3A, 3B is of the two-stage compression type. Another difference lies in the fact that each fluid-filled machine 3A, 3B also includes a cylinder 9 containing the piston 4.

[0062] In particular, the cylinder 9 and the piston 4 define a second chamber 62. In addition, the piston 4 and the cylinder 9 are movable relative to each other for the compression and expansion of the fluid in the second chamber 62.

[0063] For the operation of the pump 100 according to this second embodiment, the fluid 2 is admitted first into the second chamber 62 where it is compressed once and then transferred into the first chamber 61 via a transfer system to be compressed a second time, before being discharged to the outside via the first discharge system described previously.

[0064] The second chamber 62 communicates with the reservoir 1 of pump 100 by means of a second inlet system and a second outlet system. In particular, the second inlet system is configured to establish fluidic communication between the second chamber 62 of each fluid machine 3A, 3B and the reservoir 1 of pump 100. That is to say, each second chamber 62 is configured to be supplied with fluid at the same pressure, here equal to the pressure in the reservoir 1 of pump 100.

[0065] The second inlet system includes at least one light 94 and at least one second inlet port 95, which may be equipped with a second inlet valve 95a. The second discharge system includes at least one second discharge port 96 equipped with a second discharge valve 96a.

[0066] In the illustrated example, cylinder 9 comprises a side wall 91, a first bottom 92, and a second bottom 93 opposite the first bottom 92 with respect to the side wall 91. The port 94 is formed at the side wall 91. The second intake port 95 is formed at the first bottom 92 of cylinder 9. Similarly, the second discharge port 96 is also formed at the first bottom 92 of cylinder 9.

[0067] The transfer system between the second chamber 62 and the first chamber 61 includes at least one transfer port equipped with a transfer valve. The transfer port may also be equipped with a diffuser.

[0068] In particular, the transfer valve is designed to pass the fluid from the second chamber 62 to the first chamber 61 with the fewest possible restrictions while withstanding a significant pressure during the compression of the fluid in the first chamber 61. The diffuser is intended to promote a mixing between a flow of fluid 2 from the reservoir 1 of the pump 100 and a flow of leaks recovered by the collection element 8.

[0069] Advantageously, the transfer port(s) are formed by the first intake port(s) 44 formed at the first base 42 of the piston 4. Similarly, the transfer valve(s) are also formed by the first intake valve(s) 44a provided at the first base 42 of the piston 4.

[0070] To seal the second chamber 62, gaskets are provided between the circumference 41 of the piston 4 and the side wall 91 of the casing. For mounting these gaskets, the circumference 41 of the piston 4 may be provided with notches forming receiving grooves. The gaskets provided between the piston 4 and the cylinder 9 may be of the same type as the gaskets 7 provided between the guide 5 and the piston 4.

[0071] In the following, the second chamber 62 will also be referred to as the "first compression stage". The first chamber 61 will also be referred to as the "second compression stage".

[0072] In a first variant of this second embodiment illustrated in [Fig. 5] à [Fig. 8] The collection element 8 is configured to recover a first leakage stream from the first chamber 61 of the first fluid machine 3A and transfer said first stream to the first chamber 61 of the second fluid machine 3B. Similarly, the collection element 8 is configured to recover a second leakage stream from the first chamber 61 of the second fluid machine 3B and transfer said second leakage stream to the first chamber 61 of the first fluid machine 3A.

[0073] In this configuration, the collection element 8 is configured to recover a leakage flow produced by the second compression stage of any one of the fluid-filled machines 3A, 3B and transfer it to the second compression stage of the other of the fluid-filled machines 3A, 3B. That is to say, the leakage flow is transferred into a first chamber 61 corresponding to the same second compression stage as the other first chamber 61.

[0074] In a first configuration illustrated at the [ Fig. 5 ], the first fluid machine 3A is at the end of its intake stroke while the second fluid machine 3B is at the end of its compression stroke.

[0075] At the level of the first fluid machine 3A, the second inlet valve 95a, the ports 94, the first discharge valve 54a, and the collection valves 57a are closed. Conversely, the injection valve 56a, the transfer valve 44a, and the second discharge valve 96a are open.

[0076] At the level of the second fluid machine 3B, the second inlet valves 95a, the first discharge valve 54a, the collection valves 57a and the ports 94 are open. Conversely, the injection valve 56a, and the transfer valve 44a are closed.

[0077] In a second configuration illustrated in the [ Fig. 6 The first fluid machine 3A is in compression and intake. Component 8 collects a leakage flow from the first fluid machine 3A and transfers it to the second fluid machine 3B. The second fluid machine 3B is at the end of the intake phase of a flow of fluid 2 contained in reservoir 1.

[0078] At the first fluid-filled machine 3A, the injection valve 56a, the transfer valve 44a, and the second discharge valve 96a are now closed. The ports 94 remain closed. Conversely, the second inlet valves 95a, the collection valves 57a, and the first discharge valve 54a are open.

[0079] At the level of the second fluid-filled machine 3B, the inlet valves 95a and the first discharge valve 54 are now closed. The transfer valve 44a remains closed and the ports 94 remain open. However, the injection valve 56a is now open.

[0080] In a third configuration illustrated in the [ Fig. 7 The first fluid machine 3A is in the compression and discharge phase. Element 8 collects a leakage flow from the first fluid machine 3A. The second fluid machine 3B is in a mixing state of the leakage flow from the collection element 8 and the fluid flow previously admitted from reservoir 1.

[0081] At the first fluid-filled machine 3A, the injection valve 56a, the transfer valve 44a, and the second discharge valve 96a remain closed. The first inlet valves 95a and the collection valves 57a remain open. The first discharge valve 54a and the ports 94 are now open.

[0082] At the level of the second fluid machine 3B, the second inlet valves 95a, the second discharge valves 96a, the first discharge valve 54, the collection valves 57a and the ports 94 are closed. Conversely, the injection valve 56a and the transfer valve 44a are now open.

[0083] Finally, in a fourth configuration illustrated in the [ Fig. 8 The first fluid machine 3A is at the end of its compression cycle. Component 8 is at the end of its collection cycle. The second fluid machine 3B is at the end of its intake cycle and at the end of its recovery of the leakage flow collected by component 8.

[0084] At the first fluid-filled machine 3A, the injection valve 56a, the transfer valve 44a, and the second discharge valve 96a remain closed. The first discharge valve 54a, the collection valves 57a, and the ports 94 remain open. The second inlet valves 95a are now closed.

[0085] At the level of the second fluid machine 3B, the inlet valves 95a, the first discharge valve 54, the collection valves 57a, and the ports 94 remain closed. The injection valve 56a remains open. However, the transfer valve 44a is now closed.

[0086] In a second variant of this second embodiment illustrated in [Fig. 9] à [Fig. 12] Two leak collection devices 8 are provided. A first collection device 8A is configured to collect a first leakage stream from the first chamber 61 of the first fluid machine 3A and transfer said first stream to the second chamber 62 of the second fluid machine 3B. A second collection device 8B is configured to collect a second stream from the first chamber 61 of the second fluid machine 3B and transfer said second stream to the second chamber 62 of the first fluid machine 3A.

[0087] To do this, according to this variant of the invention, in each fluid machine 3A, 3B a second injection orifice 97 is formed at the level of the first bottom 92 of the cylinder 9. The second injection orifice 97 is provided with a second injection valve 97a.

[0088] The operation of pump 100 according to this variant of the invention is described in relation to figures [Fig. 9] to [Fig. 12].

[0089] In a first configuration illustrated at the [ Fig. 9 The first fluid machine 3A is at the end of its intake stroke. The second fluid machine 3B is at the end of its compression stroke. Only the second collection device 8B recovers the leaks from the first chamber 61 of the second fluid machine 3B and transfers them to the second chamber 62 of the first fluid machine 3A.

[0090] At the level of the first fluid machine 3A, the collection valves 57a, the first discharge valve 54a, and the second inlet valves 95a are closed. Similarly, the ports 94 are closed. Conversely, the second injection valve 97a and the second discharge valve 96a are open.

[0091] At the level of the second fluid machine 3B, the collection valves 57a, the first discharge valve 54a, and the second inlet valves 95a are open. Similarly, the ports 94 are uncovered. Conversely, the transfer valve 44a, the second injection valve 97a, and the second discharge valve 96a are closed.

[0092] In a configuration illustrated in the [ Fig. 10 The first fluid machine 3A is in the compression phase. Only the first leak collection unit 8A is in operation. The second fluid machine 3B is in the recovery phase of a leakage flow from the first collection unit 8A.

[0093] At the level of the first fluid-filled machine 3A, the collection valves 57a and the second inlet valves 95a are now open. The ports 94 and the first discharge valve 54a remain closed. The transfer valve 44a, the second injection valve 97a, and the second discharge valve 96a are now closed.

[0094] At the level of the second fluid machine 3B, the collection valves 57a, the first discharge valve 54a, the second inlet valves 95a, and the second discharge valve 96a are now closed. Conversely, the second injection valve 97a is now open. The ports 94 remain uncovered.

[0095] In a configuration illustrated in the [ Fig. 11 The first fluid machine 3A is in the compression and discharge phase, releasing the compressed fluid to the outside. The first collection unit 8A remains in operation. The second fluid machine 3B is in a mixing configuration, combining a leakage flow received from the first collection unit 8A with a fluid flow previously admitted from reservoir 1.

[0096] At the first fluid-filled machine 3A, the collection valves 57a and the second inlet valves 95a remain open. The first discharge valve 54a and the ports 94 are now open. The transfer valve 44a, the second injection valve 97a, and the second discharge valve 96a remain closed.

[0097] At the level of the second fluid machine 3B, the collection valves 57a, the first discharge valve 54a, the second inlet valves 95a, and the second discharge valve 96a remain closed, while the second injection valve 97a and the transfer valve 44a remain open. The ports 94 are now closed.

[0098] In a configuration illustrated in the [ Fig. 12 The first fluid-filled machine 3A is at the end of its compression cycle. The first collection unit 8A remains in operation. The second fluid-filled machine 3B is at the end of its intake cycle.

[0099] At the level of the first fluid-filled machine 3A, the collection valves 57a and the first discharge valve 54a and the ports 94 remain open; while the transfer valve 44a, the second injection valve 97a and the second discharge valve 96a remain closed. The second inlet valves 95a are now closed.

[0100] At the level of the second fluid machine 3B, the collection valves 57a, the first discharge valve 54a, the second inlet valves 95a, and the ports 94 remain closed; while the second injection valve 97a remains open. Furthermore, the second discharge valve 96a is now open.

[0101] In all the embodiments described, the collection element 8 is configured to recover a leakage flow produced at the outlet or at the level of a compression stage of a first fluid machine 3A, here the first chamber 61 of the machine 3A, and transfer it into the corresponding compression stage of a second fluid machine, here the first chamber 61 of the machine 3B, and vice versa.

[0102] In other words, the two fluid machines 3A and 3B have an identical or similar structure, and each fluid machine 3A and 3B has the same number of compression stages. The collection device 8 is configured to recover and transfer leakage flow between corresponding stages of the fluid machines 3A and 3B.

[0103] The invention could also be applied to two fluid machines having a different number of compression stages, provided that the collection element 8 is configured to recover and transfer a leakage flow between stages working at the same pressure or similar pressures.

[0104] Advantageously, the two fluid machines 3A, 3B can be configured to operate in opposite phases: the first chamber 61 of one of the fluid machines 3A, 3B is configured to be in the compression phase while the first chamber 61 of the other fluid machine 3A, 3B is in the intake phase. The collection device 8 is then configured to transfer the leaks produced at the outlet or at the level of the first chamber 61, which is in the compression phase, to the other first chamber 61, which is in the intake phase.

[0105] The first chamber 61 of the first fluid machine 3A and the first chamber 61 of the second machine 3B can be configured to be supplied with fluid at the same pressure.

Claims

1. Pumping apparatus (3) comprising a first fluid machine (3A) and a second fluid machine (3B), separate and independent from the first fluid machine (3A), each comprising a piston (4) and a guide (5) disposed inside the piston (4), the guide (5) and the piston (4) delimiting a first chamber (61) for compression and expansion of a fluid, the piston (4) and the guide (5) being movable relative to each other for the compression and expansion of the fluid in the first chamber (61), the first fluid machine (3A) and the second fluid machine (3B) also each comprising a sealing device (7) disposed between the piston (4) and the guide (5), characterized in thatIt includes a collection organ (8) configured to collect at least part of the leaks that have migrated through the sealing device (7) of one of the fluid machines (3A, 3B) and direct these collected leaks into the first chamber (61) of the other of the fluid machines (3A, 3B).

2. Apparatus (3) according to the preceding claim, in which the first fluid machine (3A) and the second fluid machine (3B) are configured to operate in an antagonistic mode, i.e. a decompression configuration in the first fluid machine (3A) coincides with a compression configuration in the second fluid machine (3B), and vice versa.

3. Apparatus (3) according to any one of claims 1 or 2, wherein the first fluid machine (3A) and the second fluid machine (3B) each comprise at least one leakage path between the sealing device (7) and the piston (4), the collecting member (8) having a first end in fluidic communication with the leakage path of one of the fluid machines (3A, 3B) and a second end in communication with the first compression chamber (61) of the other of the fluid machines (3A, 3B).

4. Apparatus (3) according to the preceding claim, wherein the collection element (8) further comprises at one of the fluid machines (3A, 3B) a first non-return valve (57a) configured to control the fluidic circulation between the collection element (8) and the leakage path of said machine, the collection element (8) also comprising at the other of the fluid machines (3A, 3B) a second non-return valve (57a) configured to control the fluidic circulation between the collection element (8) and the first compression chamber (61) of said fluid machine (3A, 3B).

5. Apparatus (3) according to any one of the preceding claims, comprising a venting conduit (83) connected to the collection member (8), the conduit (83) being configured to vent a portion of the collected leakage flow outside the fluid machines (3A, 3B).

6. Apparatus (3) according to any one of the preceding claims, wherein the sealing device (7) comprises a set of O-rings arranged in housings provided between the piston (4) and the guide (5).

7. Apparatus (3) according to any one of the preceding claims, in which each fluid machine (3A, 3B) includes a fluid admission system (44, 44a, 94, 95, 95a) into the first chamber (61).

8. Apparatus (3) according to any one of the preceding claims, in which each machine (3A, 3B) comprises a system (54, 54a, 94, 94a, 96, 96a) for discharging the compressed fluid out of the first expansion and compression chamber (61).

9. Apparatus (3) according to any one of the preceding claims, wherein at least one of the fluid machines (3A, 3B) comprises a second expansion and compression chamber (62), the second chamber (62) being delimited by the piston (4) and / or the guide (5) and a cylinder (9), the second chamber (62) being in communication with the first chamber via a transfer system (44, 44a), said machine (3A, 3B) being of the two-stage compression type, i.e. the fluid is admitted first into the second chamber (62) where it is compressed for the first time, then transferred into the first chamber (61) via the transfer system (44, 44a) to be compressed there a second time.

10. Apparatus (3) according to the preceding claim, in which the piston (4) or the guide (5) is configured to be in reciprocating relative motion with respect to the cylinder (9).

11. Apparatus (3) according to any one of the preceding claims, wherein the collection member (8) is configured to transfer at least a part of the leaks which have migrated through the sealing device (7) of one of the fluid machines (3A, 3B) to the first compression chamber (6) of the other of the fluid machines (3A, 3B).

12. Apparatus (3) according to any one of claims 9 to 11, wherein the collection element (8) is configured to transfer at least a part of the leaks which have migrated through the sealing device (7) of one of the fluid machines (3A, 3B) to the second chamber (62) of the other of the fluid machines (3A, 3B).

13. Compressor or pump (100), in particular for cryogenic fluid such as hydrogen (100) comprising a pumping apparatus (3) according to any one of the preceding claims.

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