A pumpless cryogenic liquid hydrogen centrifugal pump

Abstract

This invention discloses a pump-pool-less cryogenic liquid hydrogen centrifugal pump, relating to the field of liquid hydrogen pump technology. It includes a pump housing containing a working chamber and a motor chamber. The pump body is housed within the working chamber, and a drive motor is housed within the motor chamber. The pump housing has an inlet and an outlet. Multiple flow guide brackets are arranged between the inner wall of the motor chamber and the stator of the drive motor, forming a flow channel connecting the working chamber and the outlet between the flow guide brackets, the pump housing, and the motor stator. This flow channel helps the pressurized liquid in the working chamber directly lubricate and cool the drive motor and bearings, and allows for smooth discharge through the outlet. This invention eliminates the pump pool structure and through-holes in the motor chamber wall of traditional cryogenic liquid hydrogen submersible centrifugal pumps, simplifying the structure of the liquid hydrogen pumping device, reducing weight, and saving space. The liquid hydrogen effectively cools and lubricates the motor and bearings, and promptly removes heat and hydrogen through the outlet, improving the stability of pump operation.

Description

Technical Field

[0001] This invention relates to the field of cryogenic submersible pump technology, and in particular to a cryogenic liquid hydrogen centrifugal pump without a pump tank. Background Technology

[0002] Hydrogen is not only a clean, efficient, and sustainable secondary energy carrier, but also an important industrial raw material. With the formal promulgation and implementation of national standards such as GB / T40045—2021 "Liquid Hydrogen Fuel for Hydrogen-Powered Vehicles" and GB / T40060—2021 "Technical Requirements for Liquid Hydrogen Storage and Transportation" in November 2021, liquid hydrogen storage and transportation equipment has become particularly important. Liquid hydrogen pumps are key core equipment for improving energy efficiency, reducing costs, and being suitable for the marketization and large-scale application of the liquid hydrogen industry.

[0003] Most liquid hydrogen pumps currently on the market are submersible pumps. These pumps require a liquid hydrogen pump pool as their installation platform. The motor and bearings of the submersible pump exchange heat and lubricate with the liquid hydrogen in the pump pool through through-holes in the pump casing. Liquid hydrogen entering the pump inlet flows to the liquid hydrogen pump outlet along the bypass pipe after the impeller performs work. When the submersible pump motor generates significant heat, the small flow rate of liquid hydrogen in the pump pool through the pump casing through-holes cannot dissipate the heat in time, causing the motor temperature to rise. Since liquid hydrogen has a low boiling point at atmospheric pressure, the increased motor temperature leads to a large amount of liquid hydrogen vaporizing. This vapor accumulates above the pump pool and may be drawn into the submersible pump inlet, affecting the pump's stable operation. Furthermore, the liquid hydrogen after impeller work flows to the submersible pump outlet through the complex bypass pipe structure, resulting in significant flow losses. The presence of the pump pool also increases the size and structural complexity of the liquid hydrogen pumping device.

[0004] Therefore, how to design a pumpless cryogenic liquid hydrogen centrifugal pump that can fully cool and lubricate the motor and bearings while reducing the vaporization of liquid hydrogen caused by pump and motor heat generation, and ensure that the liquid hydrogen submersible pump can operate efficiently and stably for a long time while simplifying its structure, is an urgent technical problem to be solved. Summary of the Invention

[0005] To address the problems of complex structure, the need for a submersible pump as an installation platform, unstable operation, and significant flow losses in existing liquid hydrogen submersible pumps, this invention provides a pumpless cryogenic liquid hydrogen centrifugal pump. This solves the problems of insufficient cooling of the motor and bearings, and significant flow losses of liquid hydrogen after exiting the impeller, inherent in pump-pool-based liquid hydrogen submersible pumps. The new submersible pump is smaller, has a simpler structure, and is easier to install and maintain.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a pump housing without a pump tank, comprising an inlet pump cover, an intermediate pump cover, and an outlet pump cover connected in sequence. The pump housing has an inlet and an outlet. A working chamber and a motor chamber are provided between the inlet and the outlet. The working chamber is located on the inlet side, and the motor chamber is located near the outlet side. A pump body is disposed within the working chamber. The pump body includes a pump shaft and a functional component for transporting liquid hydrogen mounted on the pump shaft. A drive motor is disposed within the motor chamber. The drive motor drives the functional component to work via the pump shaft.

[0007] Multiple flow guide brackets are provided between the outer wall of the motor stator of the drive motor and the inner wall of the motor cavity. The flow guide brackets and the outer wall of the motor stator and the inner wall of the motor cavity form a flow channel connecting the working cavity and the drain port.

[0008] Preferably, the functional components mounted on the pump shaft include, along the liquid hydrogen transport direction, an inducer wheel, a first-stage impeller, a first-stage guide vane, a second-stage impeller, and a second-stage guide vane arranged in sequence.

[0009] Preferably, a spacer pump cover is provided between the working chamber and the motor chamber. The spacer pump cover has the same number of spacer pump cover through holes as the flow guide fixing bracket. The spacer pump cover through holes connect the working chamber and the motor chamber. The pump shaft is installed and fixed by a lower bearing and an upper bearing. The lower bearing is installed at the spacer pump cover, and the upper bearing is installed near the outlet pump cover.

[0010] Preferably, the outlet pump cover has the same number of outlet pump cover through holes as the flow guide fixing bracket, and the outlet pump cover through holes connect the motor cavity and the drain port.

[0011] Preferably, the outlet pump cover is provided with two outflow holes, which connect the motor cavity and the drain port. A small amount of liquid hydrogen in the motor cavity can flow through the upper bearing and through the outflow holes to the drain port for lubrication and cooling of the upper bearing.

[0012] Preferably, the inner wall of the motor cavity is provided with the same number of sliding mounting slots as the flow guide fixing brackets, the outer wall of the flow guide fixing brackets matches the sliding mounting slots, and the flow guide fixing brackets can be installed on the intermediate pump cover through the sliding mounting slots.

[0013] Preferably, the outer side of the interval pump cover has the same number of interval pump cover protrusions as the sliding mounting grooves, and the interval pump cover can be installed inside the intermediate pump cover through the sliding mounting grooves.

[0014] Preferably, the drain port and the motor cavity are connected and transitioned through a conical cylinder.

[0015] Preferably, the inlet pump cover and the outlet pump cover are fixed by a fixing stud, and the inlet pump cover, the intermediate pump cover and the outlet pump cover are assembled and fastened by the fixing stud; the suction port end of the pump housing is provided with an inlet flange, and the discharge port end of the pump housing is provided with an outlet flange.

[0016] The present invention also provides a method for operating the aforementioned cryogenic liquid hydrogen centrifugal pump, which includes the following steps:

[0017] After the centrifugal pump starts, liquid hydrogen enters the centrifugal pump through the suction port and then enters the working chamber. It passes through the functional components set along the pump shaft in sequence. Under the guidance of the functional components, the liquid hydrogen flows into the motor chamber through the spacer cover. Some of the liquid hydrogen flows through the flow channel formed by the inner wall of the motor chamber, the outer wall of the motor stator, and the flow guide fixing frame, which cools the motor stator at the same time. Some of the liquid hydrogen flows through the air gap between the motor stator and the motor rotor, which cools the drive motor.

[0018] Two portions of liquid hydrogen converge in the motor cavity near the outlet pump cover. Most of the liquid hydrogen flows through the outlet pump cover through-hole to the drain port, and then to the liquid hydrogen discharge pipe connected to the outlet flange. A small portion of the liquid hydrogen flows through the upper bearing and then through the two outlet through-holes on the outlet pump cover to the drain port, and then to the liquid hydrogen discharge pipe connected to the outlet flange for lubrication and cooling of the upper bearing.

[0019] In summary, compared with existing technologies, this invention provides a pump-pool-less cryogenic liquid hydrogen centrifugal pump. This pump eliminates the need for a pump pool as an installation platform, unlike traditional submersible pumps. Liquid hydrogen flows directly into the motor cavity after passing through the impeller working chamber, effectively improving the heat dissipation capacity of the motor and bearings, reducing the amount of liquid hydrogen vaporized while cooling the motor and bearings, enhancing the lubrication of the bearings and motor, simplifying the pump's structure, and reducing installation difficulty. Furthermore, by installing a flow guide bracket between the inner wall of the motor cavity and the outer wall of the drive motor stator, the flow loss of liquid hydrogen from the working chamber through the motor cavity to the outlet is reduced, improving the pump's operating efficiency and stability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic cross-sectional view of the pump body of the present invention;

[0022] Figure 2 for Figure 1 A schematic diagram of the intermediate pump cover structure;

[0023] Figure 3 for Figure 1 A schematic diagram of the flow guide fixing frame structure;

[0024] Figure 4 for Figure 1 A schematic diagram of the spacer pump cover structure;

[0025] Figure 5 for Figure 1 A schematic diagram of the outlet pump cover structure;

[0026] Figure 6 This is a schematic diagram of the pump housing of the present invention.

[0027] In the diagram: Pump casing-1; Inlet pump cover-11; Suction port-101; Drain port-102; Inlet flange-103; Outlet flange-104; Sliding mounting groove-105; Intermediate pump cover-12; Spare pump cover-13; Spare pump cover through hole-131; Spare pump cover protrusion-132; Outlet pump cover-14; Outlet pump cover through hole-141; Fixing stud-15; Working chamber-2; Inducer wheel-21; First stage impeller-22; First stage guide vane-23; Second stage impeller-24; Second stage guide vane-25; Pump shaft-27; Motor chamber-3; Guide bracket-31; Motor stator-32; Motor rotor-33; Upper bearing-34; Outlet flow hole-35; Lower bearing-36. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the three embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," "outer," and "between," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0030] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] As attached Figure 1 The diagram shows a cross-sectional view of the pumpless cryogenic liquid hydrogen centrifugal pump of the present invention, which includes a pump housing 1. The pump housing 1 is composed of an inlet pump cover 11, an intermediate pump cover 12, and an outlet pump cover 14 connected in sequence. The pump housing 1 has an inlet 101 and an outlet 102, and a working chamber 2 and a motor chamber 3 are provided between the inlet 101 and the outlet 102. The cryogenic liquid hydrogen centrifugal pump can be installed horizontally, vertically, or at an angle. Taking vertical installation as an example, after the cryogenic liquid hydrogen centrifugal pump is installed vertically, the working chamber 2 is located above the inlet 101, the motor chamber 3 is located above the working chamber 2, and the outlet 102 is located at the top of the pump housing 1. The outlet 102 and the motor chamber 3 are connected and transitioned by a conical cylinder. The pump housing 1 is connected to the liquid hydrogen input pipeline through an inlet flange 103 provided on the inlet 101 side, and the pump housing 1 is connected to the liquid hydrogen discharge pipeline through an outlet flange 104 provided on the outlet 102 side.

[0032] The working chamber 2 houses the pump body, which includes a pump shaft 26 and functional components mounted on the pump shaft 26. The motor chamber 3 houses the drive motor; the output shaft of the drive motor can be coaxially connected to the pump shaft, or it can be... Figure 1 The diagram shows an integrated structure. During operation, the drive motor rotates the functional components, thereby enabling the liquid hydrogen to be transported from the low-pressure zone to the high-pressure zone.

[0033] The functional component is used to achieve pressurized delivery of liquid hydrogen. In an optional embodiment of the present invention, the functional component includes an inducer 21, a first-stage impeller 22, a first-stage guide vane 23, a second-stage impeller 24, and a second-stage guide vane 25 arranged sequentially. It should be noted that the specific composition, number of impeller stages, and number of guide vane stages of the functional component are not limitations of this solution.

[0034] Reference Appendix Figure 2 Schematic diagram of intermediate pump cover structure and appendix Figure 3A schematic diagram of the flow guide bracket structure shows that multiple flow guide brackets 31 are provided between the outer wall of the motor stator 32 of the drive motor and the inner wall of the motor cavity 3. In a preferred embodiment of the present invention, the multiple flow guide brackets 31 are equally spaced along the circumferential direction of the inner wall of the motor cavity 3. Each flow guide bracket 31 has a certain length, width, and thickness. Its length direction is the axial direction of the pump housing, and its thickness direction is the radial direction of the pump housing. The flow guide brackets 31 form a flow channel connecting the working cavity 2 and the drain port 102 between the outer wall of the motor stator 32 and the inner wall of the motor cavity 3. The width of the flow channel is determined by the circumferential distance between two adjacent flow guide brackets 31, and the length and thickness of the flow channel are determined by the length and thickness of the flow guide brackets 31, respectively. For ease of installation, the intermediate pump cover 12 is provided with the same number of sliding mounting slots 105 as the flow guide fixing bracket 31. The outer wall surface of the flow guide fixing bracket 31 matches the sliding mounting slot 105, and the flow guide fixing bracket 31 can be installed on the intermediate pump cover 12 through the sliding mounting slot 105.

[0035] Specifically, in this embodiment, the number of flow guide fixing brackets 31 is eight. The specific number of flow guide fixing brackets 31 is not a limitation of this solution.

[0036] In one embodiment of the present invention, the pump shaft 26 and the output shaft of the drive motor are an integral structure. In order to fix the pump shaft 26 and ensure smooth operation, the pump shaft 26 is installed and fixed by the lower bearing 36 and the upper bearing 34, and passes through the motor rotor 33 of the drive motor.

[0037] Appendix Figure 4 For the appendix Figure 1 A schematic diagram of the intermediate pump cover 13 is shown. The intermediate pump cover 13 is located inside the intermediate pump cover 12 and is used to separate the working chamber 2 and the motor chamber 3. (See attached diagram) Figure 4 As shown, the interval pump cover 13 is provided with the same number of interval pump cover through holes 131 as the flow guide fixing bracket 31, and the interval pump cover through holes 131 connect the working chamber 2 and the motor chamber 3. The outer side of the interval pump cover 13 is provided with the same number of interval pump cover protrusions 132 as the sliding mounting grooves 105, and the interval pump cover 13 can be installed in the intermediate pump cover 12 by the cooperation of the interval pump cover protrusions 132 and the sliding mounting grooves 105.

[0038] Appendix Figure 5 For the appendix Figure 1 A schematic diagram of the structure of the outlet pump cover 14. (See attached diagram) Figure 5 As shown, the outlet pump cover 14 is provided with the same number of outlet pump cover through holes 141 as the flow guide fixing bracket 31. The outlet pump cover through holes 141 connect the motor cavity 3 and the drain port 102.

[0039] In one specific embodiment of the present invention, such as Figure 1As shown, the suction port 101 is located at the bottom of the inlet pump cover 11, and the discharge port 102 is located at the top of the outlet pump cover 14. Figure 1 As shown, the upper bearing 34 is installed near the outlet pump cover 14, while the lower bearing 36 is installed at the spacer pump cover 13.

[0040] In one specific embodiment of the present invention, such as Figure 1 As shown, the outlet pump cover 14 is provided with two outlet holes 35. The outlet holes 35 connect the motor cavity 3 and the drain port 102. A small amount of liquid hydrogen in the motor cavity 3 can flow through the upper bearing 34 and through the outlet holes 35 to the drain port 102 for lubrication and cooling of the upper bearing 34.

[0041] When the centrifugal pump starts, liquid hydrogen enters the centrifugal pump through the suction port 101 and then enters the working chamber 2. It passes sequentially through the functional components arranged along the pump shaft 26. Guided by the last stage guide vanes, the liquid hydrogen flows into the motor chamber 3 through the spacer cover through-hole 131 on the spacer cover 13. Part of the liquid hydrogen flows through the flow channel formed by the inner wall of the motor chamber 3, the outer wall of the motor stator 32, and the guide fixing frame 31, simultaneously cooling the motor stator. Another part of the liquid hydrogen flows through the air gap between the motor stator 32 and the motor rotor 33, cooling the drive motor. The two parts of liquid hydrogen merge near the outlet pump cover 14 in the motor chamber 3. Most of the liquid hydrogen flows through the outlet pump cover through-hole 141 on the outlet pump cover 14 to the drain port 102, and then to the liquid hydrogen discharge pipe connected to the outlet flange 104. A small portion of the liquid hydrogen flows through the upper bearing 34 and then through the two outlet through-holes 35 on the outlet pump cover 14 to the drain port 102, and then to the liquid hydrogen discharge pipe connected to the outlet flange 104. This scheme combines liquid hydrogen transportation with the heat dissipation and lubrication of the drive motor and rotating mechanism, eliminating the traditional pump pool structure, reducing the overall volume of the device, reducing the flow resistance of liquid hydrogen during pump transportation, improving the cooling and lubrication efficiency of the drive motor and rotating mechanism, and effectively ensuring the high efficiency and stability of the pump pool-less liquid hydrogen centrifugal pump.

[0042] As an optional implementation, the number of interval pump cover through holes 131 provided on the interval pump cover 13 may be different from the number of flow guide fixing brackets 31, and the number of outlet pump cover through holes 141 provided on the outlet pump cover 14 may be different from the number of flow guide fixing brackets 31. The number of interval pump cover through holes 131 and outlet pump cover through holes 141 are not a limitation of this solution.

[0043] The shape of the flow guide fixing bracket 31 can also be other shapes, and the shape of the flow guide fixing bracket 31 is not a limitation of this solution.

[0044] Appendix Figure 6 This is a schematic diagram of the pump housing 1 of the liquid hydrogen centrifugal pump. (See attached diagram.) Figure 6As shown, the inlet pump cover 11 and the outlet pump cover 14 of the pump housing 1 are fixed by eight fixing bolts 15. The inlet pump cover 11, the intermediate pump cover 12, and the outlet pump cover 14 are assembled and fastened by fixing bolts 15.

[0045] As an optional implementation, to prevent cold loss, a vacuum jacket and insulation layer can be installed on the outside of the pump housing for insulation.

[0046] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A pumpless cryogenic liquid hydrogen centrifugal pump, comprising a pump housing (1), characterized in that: The pump housing includes an inlet pump cover (11), an intermediate pump cover (12), and an outlet pump cover (14) connected in sequence. The pump housing (1) is provided with an inlet (101) and a outlet (102). A working chamber (2) and a motor chamber (3) are provided between the inlet (101) and the outlet (102). The working chamber (2) is located on the inlet side, and the motor chamber (3) is located near the outlet side. The working chamber (2) is provided with a pump body. The pump body includes a pump shaft (26) and a functional component for transporting liquid hydrogen installed on the pump shaft (26). The motor chamber (3) is provided with a drive motor. The drive motor drives the functional component to work through the pump shaft (26). Multiple flow guide brackets (31) are provided between the outer wall of the motor stator (32) of the drive motor and the inner wall of the motor cavity (3). The flow guide brackets (31) form a flow channel between the outer wall of the motor stator (32) and the inner wall of the motor cavity (3) to connect the working cavity (2) and the drain port (102). An interval pump cover (13) is provided between the working chamber (2) and the motor chamber (3). The interval pump cover (13) has the same number of interval pump cover through holes (131) as the flow guide fixing frame (31). The interval pump cover through holes (131) connect the working chamber (2) and the motor chamber (3). The pump shaft (26) is installed and fixed by a lower bearing (36) and an upper bearing (34). The lower bearing (36) is installed at the interval pump cover (13), and the upper bearing (34) is installed near the outlet pump cover (14). The inner wall of the motor cavity (3) is provided with the same number of sliding mounting grooves (105) as the flow guide fixing bracket (31). The outer wall of the flow guide fixing bracket (31) matches the sliding mounting groove (105). The flow guide fixing bracket (31) can be installed on the intermediate pump cover (12) through the sliding mounting groove (105).

2. The cryogenic liquid hydrogen centrifugal pump without a pump tank according to claim 1, characterized in that: The functional components mounted on the pump shaft (26) along the liquid hydrogen transport direction include an inducer wheel (21), a first-stage impeller (22), a first-stage guide vane (23), a second-stage impeller (24), and a second-stage guide vane (25) arranged in sequence.

3. The cryogenic liquid hydrogen centrifugal pump without a pump tank according to claim 1, characterized in that: The outlet pump cover (14) is provided with the same number of outlet pump cover through holes (141) as the flow guide fixing frame (31), and the outlet pump cover through holes (141) connect the motor cavity (3) and the drain port (102).

4. A pumpless cryogenic liquid hydrogen centrifugal pump according to claim 1, characterized in that: The outlet pump cover (14) is provided with two outlet holes (35). The outlet holes (35) connect the motor cavity (3) and the drain port (102). A small amount of liquid hydrogen in the motor cavity (3) can flow through the upper bearing (34) and through the outlet holes (35) to the drain port (102) for lubrication and cooling of the upper bearing (34).

5. A pumpless cryogenic liquid hydrogen centrifugal pump according to claim 1, characterized in that: The outer side of the interval pump cover (13) is provided with the same number of interval pump cover protrusions (132) as the sliding mounting grooves (105), and the interval pump cover (13) can be installed in the intermediate pump cover (12) through the sliding mounting grooves (105).

6. A pumpless cryogenic liquid hydrogen centrifugal pump according to claim 1, characterized in that: The drain port (102) and the motor cavity (3) are connected and transitioned through a conical cylinder.

7. A pumpless cryogenic liquid hydrogen centrifugal pump according to claim 1, characterized in that: The inlet pump cover (11) and the outlet pump cover (14) are fixed by a fixing stud (15). The inlet pump cover (11), the intermediate pump cover (12) and the outlet pump cover (14) are assembled and fastened by the fixing stud (15). The pump housing (1) has an inlet flange (103) at the suction port (101) end and an outlet flange (104) at the discharge port (102) end.

8. A method for operating the cryogenic liquid hydrogen centrifugal pump according to claim 4, characterized in that, Includes the following steps: After the centrifugal pump starts, liquid hydrogen enters the centrifugal pump through the suction port and then enters the working chamber. It passes through the functional components set along the pump shaft in sequence. Under the guidance of the functional components, the liquid hydrogen flows into the motor chamber through the spacer cover. Some of the liquid hydrogen flows through the flow channel formed by the inner wall of the motor chamber, the outer wall of the motor stator, and the flow guide fixing frame, which cools the motor stator at the same time. Some of the liquid hydrogen flows through the air gap between the motor stator and the motor rotor, which cools the drive motor. Two portions of liquid hydrogen converge in the motor cavity near the outlet pump cover. Most of the liquid hydrogen flows through the outlet pump cover through-hole to the drain port, and then to the liquid hydrogen discharge pipe connected to the outlet flange. A small portion of the liquid hydrogen flows through the upper bearing and then through the two outlet through-holes on the outlet pump cover to the drain port, and then to the liquid hydrogen discharge pipe connected to the outlet flange for lubrication and cooling of the upper bearing.

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