Impeller shaft hole air pressure leak detection structure

Abstract

The utility model provides an impeller shaft hole air pressure leak detection structure which comprises an impeller, a pull rod, a sealing assembly and a tail cover. The tail cover is arranged at the tail of the impeller and is coaxial with the impeller, and the pull rod penetrates through shaft holes of the impeller and the tail cover and then is fixed through a nut; the lap joint surfaces of the tail cover and the impeller, the head end of the shaft hole of the impeller and the end part of the pull rod, and the tail cover and the pull rod are sealed through sealing assemblies; an air inlet is formed in the side face of the tail cover and communicated with the impeller and a cavity between the tail cover and the pull rod. According to the utility model, shaft hole air pressure leakage detection of the impeller before assembly is realized, and repeated disassembly and workload increase due to the shaft hole problem after assembly are avoided. According to the utility model, leak detection is carried out by using air pressure without purchasing professional leak detection equipment, so that the leak detection cost is reduced, and efficient leak detection is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to impeller shaft hole pressure test technical field especially relates to a kind of impeller shaft hole air pressure leak detection structure. BACKGROUND

[0002] The impeller of centrifugal pump is generally a cast part, and casting defects such as shrinkage cavity and crack are likely to occur inside. When the defects penetrate the shaft hole of the impeller and the outer surface, liquid will enter the shaft hole. For chemical pumps, the shaft is a dry shaft, i.e., the shaft does not come into contact with the medium. If the impeller shaft hole has defects, the medium will come into contact with the shaft, corrode the shaft, and even leak to the environment along the surface of the shaft.

[0003] The impeller casting is directly machined, and the traditional pump set is tested after being assembled. The disadvantage is that when leakage is found during the test of the entire machine, the disassembly and reassembly work is heavy, and it is necessary to verify whether the leaking part is the shaft or the impeller, i.e., the sealing gasket. If it is determined that the impeller is defective, the repair of the impeller will also affect the assembly fit size accuracy. In addition, some manufacturers have a part air pressure test process, which requires a special pressure testing machine and a method of pouring soap water on the workpiece to determine whether the shaft hole leaks. Some positions are not visible or not obvious to the naked eye, and the error is large and the cost is high. SUMMARY

[0004] The utility model aims at providing an impeller shaft hole air pressure leak detection structure that can detect the sealing degree of the impeller shaft hole in advance and reduce the subsequent assembly and disassembly workload.

[0005] To achieve the above-mentioned purpose, the utility model provides an impeller shaft hole air pressure leak detection structure, which comprises an impeller, a pull rod, a sealing assembly, and a tail cover.

[0006] The tail cover is arranged at the tail of the impeller, and the tail cover is coaxially arranged with the impeller. The pull rod is fixed by a nut after penetrating the shaft holes of the impeller and the tail cover.

[0007] The overlapping surface between the tail cover and the impeller, the end of the shaft hole of the impeller and the end of the pull rod, and the tail cover and the pull rod are sealed by the sealing assembly.

[0008] An air inlet is formed in the side surface of the tail cover, and the air inlet communicates with the cavity between the impeller and the tail cover and the pull rod.

[0009] Further, the first end of the pull rod is a sealing plate, and the diameter of the sealing plate is greater than the diameter of the shaft hole in the middle of the impeller.

[0010] The tail end of the pull rod is provided with a thread matched with the nut.

[0011] Further, the sealing assembly comprises an O-ring, a first sealing gasket, and a second sealing gasket.

[0012] The O-ring seal is fitted onto the pull rod and is located between the pull rod and the tail cap to achieve a seal. The sealing position is closer to the tail end of the pull rod than the air inlet position.

[0013] The first sealing gasket is used to seal between the lap surface of the tail cover and the impeller;

[0014] The second sealing gasket is placed between the sealing plate and the first end of the impeller shaft hole.

[0015] Furthermore, the outer diameter of the second sealing gasket is the same as the outer diameter of the sealing plate, and the inner diameter of the second sealing gasket is the same as the diameter of the rod body.

[0016] Furthermore, the inner surface of the tail cap is provided with a groove that mates with the O-ring.

[0017] Compared with the prior art, the advantages of this utility model are:

[0018] 1. This utility model enables air pressure leak detection of the impeller shaft hole before assembly, avoiding repeated disassembly due to shaft hole problems after assembly and reducing workload.

[0019] 2. This utility model utilizes air pressure for leak detection, eliminating the need to purchase specialized leak detection equipment, thus reducing the cost of leak detection and achieving efficient leak detection. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the leak detection state of the impeller shaft hole air pressure leak detection structure in an embodiment of this utility model.

[0021] Figure 2 This is a cross-sectional view of the pull rod in an embodiment of this utility model. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be further described below.

[0023] like Figure 1 As shown, this utility model proposes an impeller shaft hole air pressure leak detection structure, which consists of an impeller, a tie rod 6, a tail cover 3, an O-ring 5, a first sealing gasket 7, and a second sealing gasket 1;

[0024] like Figure 2 As shown, the first end of the pull rod 6 is a sealing plate, the diameter of which is larger than the diameter of the shaft hole in the middle of the impeller; the tail end of the pull rod 6 is provided with a thread that can be screwed into the nut 4.

[0025] Before leak detection, it is assembled in the following way: the tail cover 3 is arranged at the tail of the impeller, and the tail cover 3 is coaxially arranged with the impeller; the first sealing gasket 7 is sealed between the overlapping surface of the tail cover 3 and the impeller; the pull rod 6 penetrates the shaft hole in the middle of the impeller and the tail cover 3, the sealing plate at the head end of the pull rod 6 abuts against the surface of the shaft hole of the impeller, the tail end of the pull rod 6 is screwed with the nut 4, so that the impeller, the pull rod 6 and the tail cover 3 are fixed as a whole; the second sealing gasket 1 is sealed between the sealing plate and the head end of the shaft hole of the impeller. The outer diameter of the second sealing gasket 1 is the same as that of the sealing plate, and the inner diameter of the second sealing gasket 1 is the same as the diameter of the rod body of the pull rod 6, so as to ensure the sealing degree between the sealing plate and the end surface of the impeller. The O-shaped ring 5 is sealed on the pull rod 6 and located between the pull rod 6 and the tail cover 3 to realize sealing, and the sealing position is close to the tail end of the pull rod 6 compared with the position of the air inlet 2; the ring groove matched with the O-shaped ring 5 is arranged on the inner ring surface of the tail cover 3.

[0026] In the embodiment, as shown in Figure 1 the side surface of the tail cover 3 is provided with the air inlet 2, the air inlet 2 communicates the cavity between the impeller and the tail cover 3 and the pull rod 6, that is, the shaft hole, so that the sealing condition of the shaft hole is detected through air passage.

[0027] The working principle of the utility model is as follows: first, after the above structure is installed, it is placed beside the water tank, the water tank is filled with water, and the cover hole is connected with the air source. As Figure 1 , the assembly is placed in the water tank. The air source is opened. Whether bubbles appear is checked. The air source switch is closed, pressure is maintained for a certain time, the pressure behind the valve does not decrease obviously, and no bubbles appear in the water tank, which proves that the shaft hole of the impeller has no leakage. The utility model can achieve the same effect of higher pressure hydrostatic test by using lower air pressure test.

[0028] The above is only the preferred embodiment of the utility model, and does not limit the utility model. Any person skilled in the art can make any form of equivalent replacement, modification or change to the technical scheme and technical content disclosed by the utility model without departing from the technical scheme of the utility model, which still belongs to the protection scope of the utility model.

Claims

1. A pressure leak detection structure for an impeller shaft hole, characterized in that, The impeller, the pull rod, the sealing assembly and the tail cover are included. The tail cover is arranged coaxially with the impeller at the tail of the impeller, and the pull rod is fixed by a nut after penetrating the shaft hole of the impeller and the tail cover. The sealing assembly is arranged between the tail cover and the overlapping surface of the impeller, between the first end of the shaft hole of the impeller and the end of the pull rod, and between the tail cover and the pull rod. The side surface of the tail cover is provided with an air inlet, and the air inlet is communicated with the cavity between the impeller and the tail cover and the pull rod.

2. The shaft hole air pressure leak detection structure of claim 1, wherein, The first end of the pull rod is a sealing plate, and the diameter of the sealing plate is greater than the hole diameter of the middle shaft hole of the impeller. The tail end of the pull rod is provided with a thread matched with the nut.

3. The shaft hole air pressure leak detection structure of claim 2, wherein, The sealing assembly includes an O-shaped ring, a first sealing gasket and a second sealing gasket. The O-shaped ring is sleeved on the pull rod and arranged between the pull rod and the tail cover to realize sealing, and the sealing position is closer to the tail end of the pull rod than the position of the air inlet. The first sealing gasket is sealed between the overlapping surface of the tail cover and the impeller. The second sealing gasket is sealed between the sealing plate and the first end of the shaft hole of the impeller.

4. The shaft hole air pressure leak detection structure of claim 3, wherein The outer diameter of the second sealing gasket is the same as the outer diameter of the sealing plate, and the inner diameter of the second sealing gasket is the same as the diameter of the rod body of the pull rod.

5. The shank hole air pressure leak detection structure according to claim 3, wherein The inner ring surface of the tail cover is provided with a ring groove matched with the O-shaped ring.

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