Centrifugal water blocking structure of hydrogen circulating pump for fuel cell

Abstract

The utility model relates to the technical field of shaft sealing, in particular to a centrifugal water blocking structure of a hydrogen circulating pump for a fuel cell. Which comprises a shaft and a sealing assembly for sealing a space between the shaft and a shell of the hydrogen circulating pump, and is characterized in that a centrifugal impeller is fixedly sleeved on the shaft and is positioned on one side, deviating to a compression cavity body, of the sealing assembly; the centrifugal impeller comprises blades and a wheel disc, a shaft hole allowing a shaft to penetrate is formed in the center of the wheel disc, and the blades are evenly distributed on the wheel disc around the axis of the shaft hole. The end face where blades of the centrifugal impeller are located faces the compression cavity body. The molded line rotation direction of blades in the centrifugal impeller is the same as the rotation direction of the shaft; and a drain hole communicated with the cavity body of the compression cavity is formed in the shell of the hydrogen circulating pump corresponding to the lower part of the centrifugal impeller. According to the utility model, a very good water blocking effect can be achieved, and the service life of the hydrogen circulating pump is prolonged on the whole.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of shaft seal, especially relates to a centrifugal water blocking structure of hydrogen circulation pump for fuel cell. BACKGROUND

[0002] Fuel cell is a kind of clean and high efficiency energy, and fuel cell converts chemical energy into electric energy by the electrochemical reaction of hydrogen and oxidant such as oxygen (air). As a sub-component of fuel cell system, the role of hydrogen circulation pump is to transport the hydrogen not fully utilized in fuel cell system back to fuel cell system, to improve the utilization efficiency of hydrogen. In the process of using existing hydrogen circulation pump for passenger car and commercial vehicle, water will be generated in the process of discharging of hydrogen and oxygen chemical reaction of electric pile, and this part of water will flow along with the circulation system. When liquid water circulates to hydrogen circulation pump, due to the problem of unsatisfactory shaft sealing effect inside hydrogen circulation pump, liquid water will flow into motor end and pump head end, which increases the failure rate of motor and bearing, and affects the service life of hydrogen circulation pump.

[0003] The shaft sealing structure in the prior art adopts the sealing mode of direct contact between double-lip or single-lip oil seal and shaft sleeve, and the lip material is PTFE or other plastic material. After a period of use of hydrogen circulation pump, the sealing performance is damaged, resulting in the flow of liquid water into motor end and pump head end, and causing the shortening of the service life of motor and bearing. The centrifugal water blocking structure of hydrogen circulation pump for fuel cell is proposed to solve the problems in the prior art. SUMMARY

[0004] The utility model aims at providing a centrifugal water blocking structure of hydrogen circulation pump for fuel cell, to solve the problem that the sealing performance is damaged after long-term use in the prior art, resulting in the flow of liquid water into motor end and pump head end, causing the failure of motor and bearing, and affecting the service life of hydrogen circulation pump.

[0005] The technical scheme of the utility model is: a centrifugal water blocking structure of hydrogen circulation pump for fuel cell, comprising a shaft, a sealing assembly for sealing the space between the shaft and the shell of hydrogen circulation pump, a centrifugal impeller fixedly sleeved on the shaft, and the centrifugal impeller is located on the side of the sealing assembly deviated from the compression cavity body;The centrifugal impeller comprises blades and a disc, the center of the disc is provided with a shaft hole for the shaft to pass through, and the blades are uniformly distributed on the disc around the axis of the shaft hole;

[0006] The end face of the centrifugal impeller, where the blades are located, faces the compression cavity body;The profile line rotation direction of the blades in the centrifugal impeller is the same as the rotation direction of the shaft;

[0007] The shell of the hydrogen circulation pump is provided with a drain hole corresponding to the lower part of the centrifugal impeller and communicating with the compression cavity.

[0008] Preferably, the wheel disc is vertically sectioned, and the disc surface of the wheel disc is connected by a concave circular arc line and a straight line from inside to outside.

[0009] Preferably, the length of the concave circular arc line is 3mm.

[0010] Preferably, the shell comprises a cavity shell and an end cover shell, and the cavity shell and the end cover shell are both matched with the radial edge gap of the centrifugal impeller, and the gap is 0.1-0.3mm.

[0011] Preferably, the cavity shell is provided with a first drain hole corresponding to the lower part of the centrifugal impeller and communicating with the compression cavity, and the end cover shell is provided with a second drain hole corresponding to the lower part of the centrifugal impeller and communicating with the compression cavity.

[0012] Preferably, the inlet angle β1 of the blade is 30°-40°, and the outlet angle β2 of the blade is 20°-30°.

[0013] Preferably, the thickness of the blade is uniform and consistent, and the thickness is 1-1.5mm.

[0014] Preferably, the number of the blades is 5-7.

[0015] Compared with the prior art, the hydrogen circulation pump has the following advantages:

[0016] The centrifugal water blocking structure of the hydrogen circulation pump for the fuel cell comprises a shaft, a fixed sleeve arranged on the shaft, and a centrifugal impeller arranged in the fixed sleeve, wherein the centrifugal impeller is located on the side of the sealing assembly deviated from the compression cavity; when the hydrogen circulation pump is started at a low speed, the pressure of the water vapor is small, and the impact on the sealing assembly is also small; the sealing assembly in the prior art can well block the water vapor, and the water flows out from the first drain hole / second drain hole of the cavity shell / end cover shell under the action of its own gravity; when the hydrogen circulation pump is operated at a high speed, the centrifugal blade can also well block the water vapor from flowing to the rear bearing and the sealing assembly, so that the centrifugal impeller and the sealing assembly in the prior art can achieve a very good water blocking effect, and the service life of the hydrogen circulation pump is improved as a whole. BRIEF DESCRIPTION OF DRAWINGS

[0017] The utility model will be further described in connection with the drawings and examples:

[0018] Figure 1 It is a longitudinal section view of the hydrogen circulation pump of the centrifugal water blocking structure of the hydrogen circulation pump for the fuel cell;

[0019] Figure 2This is a cross-sectional view of a hydrogen circulation pump with a centrifugal water-blocking structure for a fuel cell hydrogen circulation pump as described in this embodiment.

[0020] Figure 3 for Figure 2 An enlarged structural diagram at point A;

[0021] Figure 4 This is a cross-sectional view of the centrifugal impeller of the centrifugal water-blocking structure of a hydrogen circulation pump for a fuel cell described in this embodiment.

[0022] Figure 5 This is a top view of the centrifugal impeller of the centrifugal water-blocking structure of a hydrogen circulation pump for a fuel cell described in this embodiment;

[0023] Figure 6 This is a three-dimensional structural diagram of the centrifugal impeller of the centrifugal water-blocking structure of a hydrogen circulation pump for fuel cells described in this embodiment.

[0024] Among them: 1. drive shaft, 2. driven shaft, 3. centrifugal impeller, 4. blade, 5. impeller, 6. shaft hole, 7. cavity shell, 8. end cover shell, 9. first drainage hole, 10. second drainage hole, 11. sealing assembly, 12. concave arc line, 13. compression cavity. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to specific embodiments:

[0026] In the description of the utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0027] like Figures 1-3 As shown, a centrifugal water-blocking structure for a hydrogen circulation pump used in a fuel cell includes a shaft and a sealing assembly 11 that seals the space between the shaft and the housing of the hydrogen circulation pump. In this embodiment, the shaft is either the driving shaft 1 or the driven shaft 2 in the hydrogen circulation pump. A centrifugal impeller 3 is fixedly sleeved on the shaft, and the centrifugal impeller 3 is located on the side of the sealing assembly 11 biased towards the compression chamber 13. Figures 4-6As shown, the centrifugal impeller 3 includes blades 4 and a disc 5, the disc 5 is provided with a shaft hole 6 for the shaft to pass through, the blades 4 are uniformly distributed on the disc 5 around the axis of the shaft hole 6; the centrifugal impeller 3 is provided with an end face where the blades 4 are located, the end face faces the compression cavity 13; the profile of the blades 4 in the centrifugal impeller 3 is in the same direction as the rotation direction of the shaft; the shell of the hydrogen circulating pump is provided with a hydrophobic hole corresponding to the centrifugal impeller 3 below, the hydrophobic hole is communicated with the compression cavity 13. After the disc 5 is vertically cut, the disc surface of the disc 5 is connected by an inner concave circular arc line 12 from inside to outside. The length (as shown by the black bold line in the figure) of the inner concave circular arc line 12 is 3mm, the inner concave circular arc line 12 makes the gas movement more smooth, and the water-proof performance of the impeller is optimized. Figure 4

[0028] The shell includes a cavity shell 7 and an end cover shell 8, the cavity shell 7 and the end cover shell 8 are both in clearance fit with the radial edge of the centrifugal impeller 3, the clearance is 0.1-0.3mm; as shown, the end cover shell 8 is in clearance fit with the radial edge of the centrifugal impeller 3, the clearance L is 0.1-0.3mm. The cavity shell 7 is provided with a first hydrophobic hole 9 corresponding to the centrifugal impeller 3 below, the first hydrophobic hole 9 is communicated with the compression cavity 13, the end cover shell 8 is provided with a second hydrophobic hole 10 corresponding to the centrifugal impeller 3 below, the second hydrophobic hole 10 is communicated with the compression cavity 13. As shown, the inlet angle β1 of the blades 4 is 30°-40°, the outlet angle β2 of the blades 4 is 20°-30°. The thickness H of the blades 4 is uniform, the thickness H (as shown) is 1-1.5mm, which can reduce the gas-liquid impact. The number of the blades 4 is 5-7, so as to reduce the blade 4 extrusion, thereby reducing the absolute speed and the relative speed of the blade 4 inlet, and improving the anti-cavitation ability of the impeller. Figure 3 Figure 5 Figure 4

[0029] The working principle of the utility model is as follows: the centrifugal impeller 3 is added in front of the existing sealing assembly, when the hydrogen circulating pump is started at low speed, water vapor flows into the 0.1-0.3mm gap between the cavity shell 7 / end cover shell 8 and the centrifugal impeller 3, and the water entering at low speed flows out from the first hydrophobic hole 9 / second hydrophobic hole 10 of the cavity shell 7 / end cover shell 8 due to the action of gravity; when the hydrogen circulating pump is stably operated at high speed, the gas quickly enters the centrifugal impeller 3, so that a high pressure area is quickly established at the edge of the centrifugal impeller 3, a low pressure area is formed in the center, and the water vapor is extruded out by the high pressure area at the edge of the centrifugal impeller 3, so that the water vapor cannot flow to the rear bearing and the sealing assembly 11 through the centrifugal impeller 3. When the surface roughness of the centrifugal impeller 3 is Ra0.8 and the surface of the centrifugal impeller 3 is sprayed with super-hydrophobic coating, the contact angle of the coating surface to water is greater than 150 degrees, and the rolling angle is less than 10 degrees, so that the centrifugal impeller 3 can play a role in water-repellent and water-blocking.

[0030] ​​​​In the utility model, the pressure of water vapor is small when the hydrogen circulating pump rotates at low speed, the impact on the sealing assembly 11 is also small, the sealing assembly 11 in the prior art can block the water vapor well, water flows out from the first drain hole 9 / second drain hole 10 of the cavity shell 7 / end cover shell 8 under the action of its own gravity; when the hydrogen circulating pump runs at high speed, the centrifugal impeller 3 can also block the water vapor from flowing to the rear bearing and sealing assembly 11 well, therefore the centrifugal impeller 3 and the sealing assembly 11 in the prior art can achieve very good water blocking effect, and the service life of the hydrogen circulating pump is improved as a whole.

[0031] The above examples are only for illustrating the technical concept and characteristics of the utility model, and the purpose is to enable those skilled in the art to understand the content of the utility model and implement it, and it cannot limit the protection scope of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of the utility model, therefore, no matter from which point of view, the examples should be regarded as exemplary and non-restrictive, the scope of the utility model is defined by the appended claims instead of the above description, therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the utility model.

Claims

1. A centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell, comprising a shaft, a seal assembly that seals a space between the shaft and a housing of the hydrogen circulation pump, characterized in that: The fixed sleeve on the shaft is provided with a centrifugal impeller, which is located on the side of the sealing assembly deviated from the compression cavity; the centrifugal impeller comprises blades and a disc, and the center of the disc is provided with a shaft hole for the shaft to pass through, and the blades are uniformly distributed around the axis of the shaft hole on the disc; The end face of the centrifugal impeller where the blades are located is towards the compression cavity; and the profile of the blades in the centrifugal impeller is in the same direction as the rotation direction of the shaft; The shell of the hydrogen circulation pump is provided with a hydrophobic hole corresponding to the lower part of the centrifugal impeller, which is in communication with the compression cavity.

2. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 1, characterized by: After the vertical section of the disc, the disc surface of the disc is connected by a concave circular arc line from inside to outside.

3. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 2, characterized by: The length of the concave circular arc line is 3mm.

4. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 1, characterized by: The shell comprises a cavity shell and an end cover shell, and the cavity shell and the end cover shell are both in clearance fit with the radial edge of the centrifugal impeller, and the clearance is 0.1-0.3mm.

5. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 4, characterized by: The cavity shell is provided with a first hydrophobic hole corresponding to the lower part of the centrifugal impeller, which is in communication with the compression cavity, and the end cover shell is provided with a second hydrophobic hole corresponding to the lower part of the centrifugal impeller, which is in communication with the compression cavity.

6. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 1, characterized in that: The inlet angle β1 of the blade is 30°-40°, and the outlet angle β2 of the blade is 20°-30°.

7. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 1, characterized by: The thickness of the blade is uniform, and the thickness is 1-1.5mm.

8. The centrifugal water blocking structure of a hydrogen circulation pump for a fuel cell according to claim 1, characterized by: The number of the blades is 5-7.

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