Equipment for pumping cryogenic fluids and a filling station including such equipment - Patents.com

Abstract

An installation (1) for pumping a cryogenic fluid is disclosed, comprising a liquid-tight housing (13) intended to contain a bath of the cryogenic fluid, the housing (13) housing a compression chamber (3) in communication with the bath and a movable piston (5) for compressing the fluid in the compression chamber (3), the piston (5) being mounted on a first end of a rod (50), the installation (1) further comprising a drive mechanism (21) for driving the second end of the rod (50) back and forth in a longitudinal direction (A), the drive mechanism (21) comprising a motor (121) with a rotating shaft (211) and a mechanical conversion system (212) for converting the rotary motion of the shaft (211) into a linear motion. In the working configuration of the installation (1), the longitudinal direction (A) of the movement of the piston rod (50) is vertical, and the motor (121) is rigidly mounted on the upper frame (6). The equipment (1) is characterized in that a mechanical transformation system (212) is rigidly coupled to a motor (21) via a tubular structure (14) arranged around a rotating shaft (211), the tubular structure (14) comprising a first end rigidly connected to the motor (121) and / or to a housing surrounding the motor (121) and a second end rigidly connected to the mechanical transformation system (212) and / or to a housing surrounding the mechanical transformation system (212), said tubular structure (14) being suitable and configured to absorb at least a portion of the torque and / or forces generated in the transmission of motion between the motor (121) and the housing (13).

Description

[Technical field]

[0001] The present invention relates to an installation for pumping a cryogenic fluid, and to a filling station including such an installation.

[0002] The present invention more particularly relates to an installation for pumping a cryogenic fluid, comprising a liquid-tight housing intended to contain a bath of the cryogenic fluid, the housing housing housing a compression chamber in communication with the bath and a piston movable to compress the fluid in the compression chamber, the piston being mounted on a first end of a rod, the apparatus comprising a drive mechanism for moving the second end of the rod back and forth longitudinally, the drive mechanism comprising a motor with a rotating shaft and a mechanical conversion system for converting the rotational motion of the rotating shaft into translational motion, in the working configuration of the installation the longitudinal direction of the travel of the piston rod is vertical, and the motor is rigidly fixed to an upper mounting structure. [Background technology]

[0003] Conventional solutions for operating a reciprocating piston pump use a motor and a mechanical conversion system (connecting rod / crank and / or reducer and / or transmission system) to convert the motion of the rotating shaft of the motor into translational motion.

[0004] Most of the known cryogenic pumps operate with the piston axis horizontal, which can be done at the cold end of the vacuum insulation.

[0005] In a hydrogen refueling station, the pump needs to be available for pumping 24 hours a day. It is therefore preferable to place the cold end in a vacuum insulated bath (Dewar vessel) of cryogenic fluid (sump) to ensure that the cold end remains cold. In such cases, a vertical orientation of the piston is more appropriate.

[0006] In such cases, specific adaptations are necessary to optimally support the pump and the drive actuator (motor and associated mechanisms). A cardan system may be utilized to transmit torque from the rotational output of the motor's gearbox to the crank of a mechanical unit that converts the rotational motion provided by the motor into a reciprocating translational motion of the piston rod. This allows optimal mounting without requiring excessively close tolerances.

[0007] However, in this arrangement the torque is transferred through the cardan axle to the mechanism that converts the rotational motion into a translational motion. There is in fact no satisfactory counter torque system. The case of the mechanism must withstand this torque. The torque is thus transferred through the entire pumping structure. This is not acceptable, especially with regard to the mechanical strength of the tank containing the bath and the overall strength of the structure.

[0008] Even if these elements were sized accordingly, there would still be a risk with respect to potential problems of vibration and fatigue.

[0009] In hydraulic solutions, it is relatively easy to position the hydraulic pump vertically, since it is relatively small. The huge supply unit may itself be moved several meters away. However, the overall arrangement and effectiveness may not be very suitable for the application.

[0010] The solution involving a linear actuator with a roller screw is also easy to implement due to its compact size, but this solution is less suitable for high pressure cryogenic applications due to its poor efficiency and reliability. Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention is to overcome all or some of the disadvantages of the prior art outlined above.

[0012] To this end, the equipment according to the invention, in other respects according to its general definition given in the preamble above, is essentially characterised in that the mechanical transformation system is rigidly connected to the motor via a tubular structure positioned around the rotating shaft, the tubular structure comprising a first end rigidly connected to the motor and / or to a case surrounding the motor and a second end rigidly connected to the mechanical transformation system and / or to a case surrounding the motor, said tubular structure being capable of and configured to absorb at least a portion of the torques and / or forces generated in the transmission of motion between the motor and the housing.

[0013] Furthermore, embodiments of the invention may include one or more of the following features: - the tubular structure includes an opening for accessing a rotating shaft; - The tubular structure is created from several assembled parts, for example two assembled half-shells, - The tubular structure is created from several assembled parts, for example two assembled half-shells, the rotating shaft is connected to the mechanical transformation system via an axle comprising a connection system such as a rigid connection or a cardan joint, - The motor is suspended from its upper mounting structure, - The mechanical conversion system is suspended from the motor via a tubular structure, - The liquid-tight enclosure is suspended from the mechanical conversion system, the installation comprises a tank of liquefied gas, in particular hydrogen, said tank being fluidly connected to the housing by a set of pipes configured to supply the fluid to be compressed to the compression chamber and to recover the vaporized fluid within the housing; - The mechanical conversion system that converts the rotational motion of the rotating shaft into the translational motion of the piston rod is of the connecting rod / crank type. - The motor is housed in a case fixed to the upper mounting structure, - the installation consists of a type with one compression stage between the inlet system and the discharge system in the compression chamber, i.e. the fluid is compressed only once; - the installation consists of a mould having two compression stages between an inlet system and a discharge system, i.e. the fluid is compressed twice, the installation comprises two compression chambers, an inlet system communicating with the first compression chamber, a transfer system communicating with the first and second compression chambers and configured to transfer the fluid compressed in the first compression chamber to the second compression chamber, the movable piston alternately compressing the fluid in the first and second compression chambers depending on the direction in which it advances, the discharge system communicating with the second compression chamber, Compression of the fluid in the compression chamber is brought about by pulling or compressing the rod.

[0014] The invention also relates to a station for filling tanks or pipes with compressed gas, comprising a source of liquefied gas, in particular a tank of liquefied hydrogen, and a discharge circuit having a first end connected to the source and at least one second end intended to be connected to the tank to be filled, the discharge circuit comprising a pumping installation according to any one of the above or below characteristics.

[0015] The invention may also relate to any alternative device or method including any combination of the above or below features within the scope of the claims.

[0016] Further specific features and advantages will become apparent from the following description, given with reference to the drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows a schematic partial perspective view illustrating a first possible embodiment of a pumping installation according to the invention. [Diagram 2] FIG. 2 shows a partial schematic perspective view illustrating details of a support structure for a pumping installation according to the invention. [Diagram 3] FIG. 3 shows a schematic partial view in cross section illustrating an example of the details of the installation, specifically the construction of the compression chamber. [Figure 4] FIG. 4 shows a schematic, partial view illustrating an example of a filling station using such a compression device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The depicted installation 1 for pumping a cryogenic fluid includes a liquid-tight enclosure 13 intended to contain a bath of cryogenic fluid. The enclosure 13 may be vacuum insulated and houses a compression chamber 3 in communication with the bath, and a movable piston 5 that can be moved to compress the fluid in the compression chamber 3 (see FIG. 3 ).

[0019] The piston 5 is mounted on a first end of a piston rod 50. The device 1 includes a drive mechanism 21 for moving the second end of the rod 50 back and forth in a longitudinal direction A of travel.

[0020] The drive mechanism 21 comprises a motor 121 (with gearbox etc., if applicable) with a rotating shaft 211 and a mechanical conversion system 212 converting the rotational movement of the rotating shaft 211 into a translational movement of the rod 50. The mechanical conversion system 212 converting the rotational movement of the rotating shaft 211 into a translational movement of the piston rod 50 may be of the type of connecting rod / crank and is housed inside the case.

[0021] As illustrated, the drive mechanism (motor 121 and conversion system 212 ) is located on the housing 13 .

[0022] This arrangement helps limit heat loss (as the hotter section is above the cooler section).

[0023] The rotating shaft 211 of the motor 121 is coupled to a mechanical transformation system 212 via an axle that includes a connection system such as a rigid connection or a Cardan joint.

[0024] Connectors containing cardan joints may allow for greater assembly tolerances.

[0025] Cardan joints connecting two objects also provide optimal transfer of "useful" torque with relatively easy maintenance.

[0026] These elements (motor 121 and mechanical conversion system 212) may be housed within their own cases.

[0027] The motion conversion system 212 (and its case) can be easily removed to access the cold end located vertically below the mechanism (particularly below the crankshaft in the case of a connecting rod / crank mechanism).

[0028] As illustrated, when the plant 1 is in the working configuration, the longitudinal direction A of travel of the piston rod 50 is vertical. The motor 121 is rigidly fixed to an upper mounting structure 6, which may for example include a cross beam.

[0029] The motor 121 may in particular be suspended from its upper mounting structure 6 .

[0030] The upper mounting structure for the motor 121 may include a first lateral support beam assembly 6, which are connected to a load-bearing structure 60 that includes vertical legs that rest on the ground.

[0031] The mechanical transformation system 212 is rigidly connected to the motor 121 via a tubular structure 14 positioned around the rotating shaft 211. This tubular structure 14 includes a first end rigidly connected to the motor 121 and / or to a case surrounding the motor 121 and a second end rigidly connected to the mechanical transformation system 212 and / or to a case surrounding the motor 121. This tubular structure 14, for example cylindrical, is rigid and can and is configured to absorb at least a portion of the torques and / or forces generated in the transmission of motion between the motor 121 and the housing 13. The cross section of the tubular structure 14 may have a shape other than circular, for example square, rectangular or some other shape.

[0032] The mechanical transformation system 212 may therefore be suspended from the motor 121 via the tubular structure 14. The liquid-tight enclosure 13 may itself be suspended from the mechanical transformation system 212.

[0033] This means that the upper end of the container 13 may be suspended from and / or connected to the lower end of the mechanical transformation system 212 (in particular its case) by means of connecting members 9 such as one or more axles and / or muff coupling sleeves. The lower end of the container 13 may therefore rest above ground level without resting on a lower support.

[0034] This tubular structure 14 advantageously has good torsional strength so that the tubular structure 14 can absorb the torque and / or forces transmitted by the motors on each end of the axle 211 .

[0035] As illustrated in Fig. 2, the tubular structure 14 may include an opening 15 for accessing the rotating shaft 211, in particular the cardan joint if the shaft 211 possesses such a joint. In particular, the rotating shaft 211 may be connected to the mechanical transformation system 212 via an axle that includes a connection system such as a rigid connection or a cardan joint, thereby allowing interventions without the need for a complete dismantling. This opening 15 may be adaptable so that it can be closed by a removable cover.

[0036] The tubular structure 14 may be made from several assembled parts, for example two half-shells assembled around the shaft 211 along a longitudinal joint.

[0037] In the illustrated example, the installation 1 comprises a tank 17 of liquefied gas, in particular hydrogen. The tank 17 is fluidly connected to the housing 13 by a set of pipes 10, 11 arranged to supply the fluid to be compressed to the compression chamber 3 and in particular to recover any boil-off gas generated from the fluid that may have been vaporized within the housing 13.

[0038] This tank 17 may be placed on the ground. As previously mentioned, the pipes 10, 11 may include flexible sections.

[0039] In particular, as described in more detail below, the cryogenic piping connecting the vessel 13 and the tank of cryogenic fluid 17 may be flexible piping to accommodate thermal contraction and to withstand slight misalignment.

[0040] The structure of the facility provides many advantages.

[0041] In addition to the transmission of motion between the motor 121 and the shaft 50 without unwanted torque, the structure is particularly well suited to facilitate maintenance (e.g. by removing the suspended elements, particularly the case, to access the mechanism).

[0042] The drive mechanism (motor and possibly gearbox or transmission) does not need to be removed during maintenance of the cold side of the cryogenic pumping section. Maintenance of the motor section 121 is generally less frequent in practice than the cold drive section. The proposed structure allows access to the cold section 212 (for visual inspection, cleaning, replacing seals, lubrication, etc.) without removing the motor section 121.

[0043] The installation 1 is compact and positioned low to the ground, which makes it well suited for integrating it into a filling station.

[0044] The motor 121 and associated gearbox may be standard components, specially explosion-proof or with enhanced safety.

[0045] The motor 121 and the conversion system 212 may be positioned in various relative configurations, in particular horizontally, vertically, and the shaft 211 rotates along its axis or perpendicular to its axis, depending on the model of the reduction gear system 212 used (helical gear, helical bevel gear, worm gear, helical parallel shaft, right angle reducer).

[0046] The assembly including the motor 211 and, if any, its reducer, which may be illustrated and from which the rotating axle 211 may protrude, may advantageously be replaced by a torque motor, if applicable (the torque motor therefore does not have a reducer or gearbox). In such a case there are no problems with oil due to lubrication. In addition, in such a case the assembly is smaller and lighter. In addition, such a motor assembly allows more flexibility in setting the speeds (speeds, especially rotational speeds, profiles).

[0047] 3 illustrates diagrammatically an example of a compression chamber (single compression stage) with an intake system 2 in communication with the compression chamber 3 and configured to allow a fluid to be compressed to enter the compression chamber 3, a piston 5 movable to compress the fluid in the compression chamber 3, and an exhaust system 7 in communication with the compression chamber 3 and configured to allow the compressed fluid to exit. Compression of the fluid in the compression chamber may occur by pulling or compressing a rod 50.

[0048] Of course, the invention also applies to pumps having two compression stages (eg two compression chambers and two compression stages for each of the two directions of lateral movement of the piston).

[0049] Figure 4 illustrates an example of a station for filling tanks or pipes with compressed gas, comprising a source 17 of liquefied gas, in particular liquefied hydrogen, and a discharge circuit 18 having a first end connected to the source and at least one second end intended to be connected to a tank 190 to be filled. The discharge circuit 18 including the compression device 1 corresponds to an installation according to any one of the above characteristics.

[0050] The housing 13 is suspended from the mechanical transformation system 212, but it can be envisaged to provide one or more legs connecting the housing to the ground, if applicable, via flexible and / or adjustable connections. This may be during maintenance operations and / or in normal operating situations, for example to better support the housing 13 and to absorb any vibrations that may be present, for example. Likewise, the lower end of the housing can rest on a support within the housing that holds it laterally, for example.

Claims

1. An installation (1) for pumping a cryogenic fluid, comprising a liquid-tight housing (13) intended to contain a bath of cryogenic fluid, said housing (13) housing a compression chamber (3) in communication with said bath and a piston (5) movable to compress said fluid in said compression chamber (3), said piston (5) being mounted on a first end of a rod (50), said device (1) comprising a drive mechanism (21) for moving a second end of said rod (50) back and forth in a longitudinal direction (A), said drive mechanism (21) comprising a motor (121) with a rotating shaft (211) and a mechanical conversion system (212) for converting a rotational movement of said rotating shaft (211) into a translational movement, in a configuration of operation of said installation (1), said longitudinal direction (A) of the travel of said piston rod (50) is vertical, said motor (121) being adapted to move said second end of said rod (50) back and forth in a longitudinal direction (A), 1. An installation (1), wherein the motor (21) is rigidly fixed to an upper mounting structure (6), the mechanical transformation system (212) is placed vertically on the housing (13) and rigidly connected to a motor (121) via a tubular structure (14) positioned around the rotating shaft (211), the tubular structure (14) including a first end rigidly connected to the motor (121) and / or to a case surrounding the motor (121) and a second end rigidly connected to the mechanical transformation system (212) and / or to a case surrounding the mechanical transformation system (212), the tubular structure (14) being capable of and configured to absorb at least a portion of the torque and / or force generated in the transmission of motion between the motor (121) and the housing (13).

2. 2. The installation according to claim 1, characterized in that the mechanical conversion system converting the rotational movement of the rotating shaft (211) into the translational movement of the piston rod (50) is of the connecting rod / crank type.

3. 3. Installation according to claim 1 or 2, characterized in that the tubular structure (14) comprises an opening (15) for accessing the rotating shaft (211).

4. 3. Installation according to claim 1 or 2, characterized in that the tubular structure (14) is made from several assembled parts, for example two assembled half-shells.

5. 3. Installation according to claim 1 or 2, characterized in that the rotating shaft (211) is connected to the mechanical transformation system (212) via an axle comprising a connection system such as a rigid connection or a Cardan joint.

6. 3. An installation according to claim 1 or 2, characterized in that the motor (121) is suspended from its upper mounting structure (6).

7. 3. The installation according to claim 1 or 2, characterized in that the mechanical transformation system (212) is suspended from a motor (121) via the tubular structure (14).

8. 3. The installation according to claim 1 or 2, characterized in that the liquid-tight enclosure (13) is suspended from the mechanical conversion system (212).

9. 3. Installation according to claim 1 or 2, characterized in that the installation (1) comprises a tank (17) of liquefied gas, in particular hydrogen, said tank (17) being fluidly connected to the housing (13) by a set of pipes (10, 11) arranged to supply the fluid to be compressed to the compression chamber and to recover the fluid vaporized within the housing (13).

10. A station for filling tanks or pipes with compressed gas, comprising a source of liquefied gas (17), in particular a tank of liquefied hydrogen, and a discharge circuit (18) having a first end connected to said source and at least one second end intended to be connected to a tank to be filled (190), said discharge circuit (18) comprising a pumping installation (1) according to claim 1 or 2.

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