WO2022243040A1

WO2022243040A1 - Compression apparatus and filling station comprising such an apparatus

Info

Publication number: WO2022243040A1
Application number: PCT/EP2022/061961
Authority: WO
Inventors: Cyril BENISTAND-HECTOR; Martin Graser
Original assignee: L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude
Priority date: 2021-05-21
Filing date: 2022-05-04
Publication date: 2022-11-24
Also published as: KR20240013111A; FR3123094A1; CN117242260A; FR3123094B1; JP2024517636A; US20240230032A1; CA3217932A1; EP4341560A1

Abstract

The invention relates to an apparatus (1) for compressing cryogenic fluid, comprising a sealed enclosure (13) intended to contain a bath (16) of cryogenic fluid, a compression chamber (3, 4) communicating with the bath, an intake system (2) communicating with the compression chamber (3, 4) and configured to allow the inlet of fluid to be compressed into the compression chamber (3), and a mobile piston (5) for compressing the fluid in the compression chamber (3, 4), the apparatus (1) also comprising an evacuation system (7) communicating with the compression chamber (3, 4) and configured to allow the outlet of compressed fluid, the piston (5) being mounted at a first end of a rod (50), the apparatus (1) comprising a mechanism (21) for driving the rod (50) in a back and forth movement along a longitudinal direction (A), the drive mechanism (21) comprising a motor (121) provided with a rotating shaft (211) and a mechanical system (212, 213) converting the rotary movement of the rotating shaft (211) into a movement in translation of a head (8) sliding along the longitudinal direction (A) and to which a second end of the rod (50) is connected, characterized in that the head (8) is mounted so as to slide and to be guided by two fixed guide rails (9) situated on either side of the head (8), and in that the head (8) and/or one rail (9) comprises a resilient portion (10), the resilient portion (10) being configured to generate, on the rail or rails (9), a force transverse to the longitudinal direction (A).

Description

Compression apparatus and filling station comprising such apparatus.

The invention relates to a compression device as well as a filling station comprising such a device. Such a device is for example a cryogenic pump, in particular for pumping liquefied hydrogen.

The invention relates more particularly to a cryogenic fluid compression apparatus comprising a sealed enclosure intended to contain a bath of cryogenic fluid, a compression chamber communicating with the bath, an intake system communicating with the compression chamber configured to allow the entry of fluid to be compressed into the compression chamber, a movable piston to ensure the compression of the fluid in the compression chamber, the apparatus further comprising an evacuation system communicating with the compression chamber and configured to allow the exit of compressed fluid, the piston being mounted at a first end of a rod, the apparatus comprising a mechanism for driving the rod back and forth in a longitudinal direction, the driving mechanism comprising a motor provided with a rotating shaft and a mechanical system converting the rotational movement of the rotating shaft into a translating movement ation of a head sliding in the longitudinal direction and to which a second end of the rod is connected.

Driven by a crank-rod mechanism is a well-known actuation solution for cryogenic piston pumps. Most of these pumps operate with oil splash lubrication to guide the piston rod. This architecture is well suited to horizontal piston rod configurations because oil leaks are very limited. The piston rod can be guided by plain bearings or anti-friction strips (eg bronze plates).

For a vertically configured cryogenic pump, it is very difficult to perform such splash lubrication for the motion converting mechanism. Indeed, the cold end of the pump is placed in a tank (generally called a sump) and the articulated mechanism must be placed vertically on top of it. Oil leaks along the piston rod due to linear reciprocating motion. The fall of oil drops on the cryogenic part is not allowed for safety reasons.

One solution is to use a leak collection and recirculation system (with pump, filter, etc.). This solution is not satisfactory.

One solution is to use a linear guide mechanism (eg roller carriages, ball bearings, etc.) without oil, mounted on the side receiving the transverse force generated. This architecture is subject to significant stresses which limit the service life and require frequent maintenance. This solution can also cause a high temperature increase requiring the installation to be shut down. In addition, the piston stroke is relatively short compared to the load (efforts). The sliding head size is close to the race size. In addition, the forces are poorly distributed due to the asymmetry of the mechanism. To take up the forces, several sliding heads can be provided or several guides can be used on the side receiving the forces with additional mechanical couplings (ball joint to allow assembly). However, this does not completely solve the problems.

An object of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

To this end, the compression device according to the invention, moreover conforming to the generic definition given in the preamble above, is essentially characterized in that the head is mounted to slide and guided by two fixed guide rails. located on either side of the head and in that the head and/or a rail comprises an elastic portion, said elastic portion being configured to generate on the rail(s) a force transverse to the longitudinal direction.

Further, embodiments of the invention may include one or more of the following features:

the compression of the fluid in the compression chamber is obtained by traction or compression of the rod, said traction or compression generating a transverse thrust of the head on one of the rails in a direction transverse to the longitudinal direction, the force generated by the elastic portion being in the opposite direction to this thrust,
the elastic portion is configured to generate on the rail(s) a transverse force having, in absolute value, an intensity less than, equal to or greater than the maximum intensity of the thrust force,
the elastic portion is located between a central zone of the head and one of the two rails,
the elastic portion is located between one of the two rails and the fixed support of said rail,
the elastic portion comprises a spring or a deformable zone and is prestressed,
in the operating configuration, the rod is movable in a back and forth movement in a vertical longitudinal direction,
the mechanical system converting the rotational movement of the rotating shaft into a translational movement of the carriage is of the connecting rod and crank type,
the mechanical system converting the rotational movement of the rotating shaft into a translational movement of the head is connected to a central zone of the head via a ball joint or pivot connection, said connection being located on a longitudinal straight line passing through the axis of translation of the rod, said straight line also being secant of the straight line passing through the rotating shaft of the motor,
the head is slidably mounted in the guide rails via a guide system with or without rolling element(s), for example a system with rollers, and/or balls and/or sliding rollers or a rail-type system ( s) precision,
the device is of the single-stage compression type, i.e. the fluid is compressed only once between the intake system and the exhaust system,
the apparatus is of the type with two compression stages, that is to say that the fluid is compressed twice between the intake system and the evacuation system, the apparatus comprising two compression chambers, the system of admission communicating with a first compression chamber, a transfer system communicating with the first and the second compression chamber and configured to allow the transfer of compressed fluid in the first compression chamber to the second compression chamber, the movable piston ensuring alternately the compression of the fluid in the first and second compression chambers according to its direction of displacement, the evacuation system communicating with the second compression chamber,
the second compression chamber is delimited by a portion of the body of the piston and a fixed wall of the device.

The invention also relates a filling station for pressurized gas tanks or pipes comprising a source of liquefied gas, in particular liquefied hydrogen, a withdrawal circuit having a first end connected to the source and at least one second end intended to be connected to a reservoir to be filled, the draw-off circuit comprising a compression apparatus conforming to any one of the characteristics above or below.

The invention may also relate to any alternative device or method comprising any combination of the characteristics above or below within the scope of the claims.

Other features and advantages will appear on reading the description below, made with reference to the figures in which:

represents a schematic and partial vertical sectional view illustrating an example of structure and operation of a compression device according to the invention,

shows a schematic and partial horizontal sectional view of a detail of the aforementioned device at the level of the arrangement of one end of a sliding head and its vertical guide rail,

shows another view in horizontal section, schematic and partial, of a detail of the aforementioned device at the level of the arrangement of one end of the sliding head and its vertical guide rail and illustrating running gear,

schematically and partially represents an example of distribution of forces at one end of the sliding head and its guide rail of the device in a traction configuration,

represents a sectional view, schematic and partial, illustrating a detail of a possible alternative embodiment of the compression chamber of such a compression device,

represents a sectional view, schematic and partial, illustrating a detail of a second possible embodiment of the compression chamber of such a compression device,

represents a sectional view, schematic and partial, illustrating a detail of a third possible embodiment of the compression chamber of such a compression device,

represents a schematic and partial view illustrating a detail of the device illustrating a possible embodiment of the structure of the elastic portion,

represents a schematic and partial view, illustrating an example of a filling station using such a compression apparatus.

The device 1 for compression of cryogenic fluid represented schematically comprises a sealed enclosure 13 intended to contain a bath 16 of cryogenic fluid (typically a liquid phase in the lower part and a gaseous phase in the upper part). The device 1 has at least one compression chamber 3 communicating with the liquid bath (in particular the compression chamber 3 is preferably immersed in the bath).

The device 1 comprises an intake system 2 communicating with the compression chamber 3 and configured to allow the entry of fluid to be compressed into the compression chamber 3 (typically comprising a system of valve(s) and/or orifice( s)).

The device 1 further comprises a movable piston 5 to ensure the compression of the fluid in the compression chamber 3 and an evacuation system 7 communicating with the compression chamber 3 configured to allow the outlet of compressed fluid (typically comprising a set valve(s) and communicating with an evacuation pipe).

The piston 5 is mounted at a first end of a rod 50. The device 1 comprises a mechanism 21 for driving the rod 50 in an alternating movement back and forth in a longitudinal direction A. The drive mechanism 21 conventionally comprises a motor 121 provided with a rotating shaft 211 and a

mechanical system

212, 213 converting the rotational movement of the rotating shaft 211 into a translational movement of a head 8 sliding in the direction A longitudinal. A second end of the rod 50 is connected to the head to receive its actuation.

The head 8 can be made up of one or more assembled parts. This head 8 can also be designated in the literature by the terms "crosshead", "crosse" or "crosshead" ("Crosshead" in English).

For example, the piston rod 50 can be connected to one end of the head 8 via a coupling part, such as a rigid connection (for example of the bolted flange type) or a flexible connection (of the ball joint or pivot type for example).

The head 8 is slidably mounted and guided by two fixed guide rails 9. The two rails 9 are located on either side of the head 8 (on either side in a direction perpendicular to the longitudinal direction A). The head 8 is guided in translation by the rails 9 and receives the pulling and pushing forces via one end of the mechanism 21, for example a connecting rod 213 is connected to the head 8 at the level of a connection 11 ball joint or pivot.

As illustrated, the mechanical system converting the rotational movement of the rotating shaft 211 into a translational movement of the head 8 can be connected to a central zone of the head 8 via a link 11 located on a longitudinal straight line A passing through the axis of translation of the rod 50. In addition, this straight line may also intersect the straight line passing through the rotating shaft 211 of the motor 210.

As shown in cross section and , each end of the head 8 can be slidably mounted on a rail 9. As visible in , the head 8 can be slidably mounted on the guide rail 9 via a set 12 of rollers and/or balls. The sliding system can also be of the precision rail type or any other suitable guide system (preferably not using oil in the case where the axis of the rod is vertical in the position of use).

For example, carriages (with rollers or ball bearings) are screwed onto the head 8 and move with it. The rails 9 are for example fixed to the frame of the device. For lubrication, a passive (or active) cartridge can nevertheless be mounted on each of the carriages.

The head 8 comprises an elastic portion 10 which is configured to generate on the rail(s) 9 a force transverse to the longitudinal direction A.

That is to say that the elastic portion 10 generates a permanent transverse force (a force) on the rail(s) 9.

The movement of compression of the fluid in the compression chamber 3 generates significant forces in the mechanism (the compression of the fluid is obtained during a traction of the rod on the representation of the ). Due to the asymmetry of the mechanism (mechanism of the eccentric type), during this compression, the lateral forces at the level of the rails 9 are not symmetrical. In particular, one rail 9 can be loaded transversely more than the other (left rail in this non-limiting example shown).

The aforementioned arrangement makes it possible to at least partially rebalance these transverse forces in the device 1.

Indeed, as schematized in , the force Fm exerted by the motion transformation mechanism 21 induces a tensile component Ft on the rod 50 and a transverse thrust component F1 towards one of the rails 9. The elastic portion 10 is configured to generate on this same rail 9 a continuous force F2 in the direction opposite to this thrust F1 and which at least partially compensates for it (for example the force F2 is sized to halve the thrust force F1). Note that a force F2 can also be generated on the other rail 9; this has no particular influence on the proper functioning of the device.

It should be noted that the intensity of this force F2 generated by the elastic portion is preferably constant, whereas the thrust F1 has an intensity which varies cyclically during the movements. The value of F2 can be chosen to partially compensate for the maximum intensity of F1 during the cycle.

The maximum thrust force (when operating at low load, the spring force will be greater than the thrust force.

That is to say, the elastic portion 10 permanently performs a "transverse compensating load". The final effort resulting in the mechanism is thus limited and makes it possible to limit the stresses in the operating phase generating the most effort. A better balancing or clipping of the transverse forces is obtained.

Thus, instead of using a threshold guide rail on one side of the head 8 (on the side receiving the forces), this solution provides a second guide rail which, together with the elastic member 10, reduces the lateral forces .

It should be noted that this arrangement also makes it possible to deal with the problems of alignment and possible spacing between the two rails 9 to ensure that the assembly is assembled correctly (assembly tolerances). As shown schematically, the elastic portion 10 can be located between the central zone of the head 8 and one of the two rails 9. This elastic portion 10 can comprise a spring or a prestressed deformable zone or any other member generating a force. appropriate. As shown schematically in , this elastic portion may comprise a spring formed by a loop-shaped portion (for example with two lobes) of a part of the body of the head 8.

It should be noted that the elastic portion 10 can be integrated into (or constituted by) the head 8. The

elements

8 and 10 can be separate parts or the same part.

In the example of the as well as in the example of , the compressive force of the fluid is obtained by a traction (rise) of the rod 50.

Of course, this is in no way limiting. Thus, and as shown in , the compressive force of the fluid can be obtained by a push (descent) of the rod 50. In this case, the lateral forces are reversed with respect to the description above. In this case, the force F2 of the elastic portion 10 can also simply be reversed (either by moving this elastic portion to the other side of the head or by modifying the structure of the elastic portion 10 so that its force is directed to oppose too great an effort on the side concerned).

Note that in the embodiment of the , the piston 5 comprises a tubular portion mounted around a fixed central guide 15 . A terminal end of the central guide 15 forming the fixed wall delimiting a part of the compression chamber 3 with the tubular portion of the piston 5.

In the aforementioned examples, the apparatus 1 is of the type with one compression stage (fluid compressed only once). Of course, the invention also applies in the same way to a compression device with two compression stages (fluid undergoing two compressions in series). The illustrates an example of a two-stage compression structure. Thus, the apparatus 1 may comprise a tubular piston 5 cooperating with a tubular cavity 14 or fixed chamber which is closed at its lower end to delimit two chambers 3, 4 of compression. The intake system 2 communicates with a first compression chamber 3. The architecture comprises a transfer system 6 (valve or other) communicating with the first 3 and the second 4 compression chamber and configured to allow the transfer of compressed fluid in the first 3 compression chamber to the second 4 compression chamber. The mobile piston 5 alternately compressing the fluid in the first 3 (towards the second chamber 4) and in the second 4 compression chamber according to its direction of movement. The evacuation system 7 communicates with the second chamber 4 of compression.

The device 1 can have the following operating characteristics: piston stroke of between 40 and 160 mm, a motor rotation speed of the order of 80 rpm to 500 rpm (corresponding to a frequency of between 1.3 Hz and 8.5 Hz for the piston 5). For a tensile force Ft, the thrust force F1 can be of the order of 10-20% of Ft while the opposite force generated by the elastic member 10 can be of the order of 5-10% from Ft.

The aforementioned solution has many advantages.

It limits the maximum load peak in the mechanism. This makes it possible to increase the lifetime of the guidance system subjected to these forces.

The architecture eliminates the need for an oil bath lubrication system that would ooze on the cryogenic part. The architecture avoids having to manage an oil bath during maintenance operations. Only any lubricators which provide passive self-lubrication in operation of certain elements of the mechanism must be recharged.). The solution is compact and lightweight and can be applied to any type of piston pump and any type of crank drive mechanism(s).

Claims

Apparatus (1) for compressing cryogenic fluid comprising a sealed enclosure (13) intended to contain a bath (16) of cryogenic fluid, a compression chamber (3, 4) communicating with the bath, an inlet system (2) communicating with the compression chamber (3, 4) configured to allow the entry of fluid to be compressed into the compression chamber (3), a piston (5) movable to ensure the compression of the fluid in the chamber (3, 4) compression, the apparatus (1) further comprising an evacuation system (7) communicating with the compression chamber (3, 4) and configured to allow the outlet of compressed fluid, the piston (5) being mounted at a first end of a rod (50), the apparatus (1) comprising a mechanism (21) for driving the rod (50) back and forth in a longitudinal direction (A), the mechanism ( 21) drive comprising a motor (121) provided with a rotating shaft (211) and a mechanical system (212, 213) converting the rotational movement of the shaft (211) rotating in a translational movement of a head (8) sliding in the longitudinal direction (A) and to which a second end of the rod (50) is connected, characterized in that that the head (8) is slidably mounted and guided by two fixed guide rails (9) located on either side of the head (8) and in that the head (8) and/or a rail (9) comprises an elastic portion (10), said elastic portion (10) being configured to generate on the rail(s) (9) a force transverse to the longitudinal direction (A), and in that the elastic portion (10) comprises a spring or a deformable zone and is prestressed.
Apparatus according to claim 1, characterized in that the compression of the fluid in the compression chamber (3, 4) is obtained by traction or compression of the rod (50), said traction or compression generating a transverse thrust of the head (8) on one of the rails (9) in a direction transverse to the longitudinal direction (A), and in that the force generated by the elastic portion (10) is in the opposite direction to this thrust.
Device according to Claim 2, characterized in that the elastic portion (10) is configured to generate on the rail or rails (9) a transverse force having, in absolute value, an intensity less than or equal to the maximum intensity of the pushing effort.
Device according to any one of Claims 1 to 3, characterized in that the elastic portion (10) is located between a central zone of the head (8) and one of the two rails (9).
Device according to any one of Claims 1 to 4, characterized in that the elastic portion (10) is located between one of the two rails (9) and a fixed support of the said rail.
Device according to any one of Claims 1 to 5, characterized in that, in the operating configuration, the rod (50) is movable according to a back and forth movement in a vertical longitudinal direction (A).
Apparatus according to any one of Claims 1 to 6, characterized in that the mechanical system (212, 213) converting the rotational movement of the rotating shaft (211) into a translational movement of the carriage (8) is of the with connecting rod (213) and crank (212).
Device according to any one of Claims 1 to 7, characterized in that the mechanical system (212, 213) converting the rotational movement of the rotating shaft (211) into a translational movement of the head (8) is connected to a central zone of the head (8) via a ball joint or pivot link (11), said link (11) being located on a longitudinal straight line (A) passing through the axis of translation of the rod (50), said straight line being further secant to the line passing through the rotating shaft (211) of the motor (210).
Device according to any one of Claims 1 to 8, characterized in that the head (8) is slidably mounted in the guide rails (9) via a guide system with rolling element(s), for example a roller system, and/or balls and/or sliding rollers or a precision rail(s) type system.
Device according to any one of Claims 1 to 9, characterized in that it is of the type with one compression stage, that is to say that the fluid is compressed only once between the intake system (2) and the evacuation system (7).
Device according to any one of Claims 1 to 10, characterized in that it is of the two-stage compression type, that is to say that the fluid is compressed twice between the intake system (2) and the evacuation system (7), the device (1) comprising two compression chambers (3, 4), the intake system (2) communicating with a first compression chamber (3), a system (6) transfer communicating with the first (3) and the second (4) compression chamber and configured to allow the transfer of compressed fluid in the first compression chamber (3) to the second (4) compression chamber, the piston (5 ) Mobile alternately compressing the fluid in the first (3) and second (4) compression chambers in its direction of movement, the evacuation system (7) communicating with the second compression chamber (4).
Device according to Claim 11, characterized in that the second compression chamber (4) is delimited by a portion of the body of the piston (5) and a fixed wall of the device.
Filling station for pressurized gas tanks or pipes comprising a source (17) of liquefied gas, in particular of liquefied hydrogen, a withdrawal circuit (18) having a first end connected to the source and at least one second end intended to be connected to a reservoir (190) to be filled, the withdrawal circuit (18) comprising a compression apparatus (1) according to any one of claims 1 to 12.