A structure for reducing the immersion depth of an immersion pump inlet

Abstract

The utility model discloses a structure for reducing the structure of the inlet immersion depth of immersion pump relates to pump product field, including the water inlet body, the flow guider, the pump shaft and the guide vane, the one end of pump shaft away from motor installs the axial flow impeller, and the one end of pump shaft close to motor is installed a plurality of stages of impellers along the axial sequence, wherein the first stage impeller to the axial flow impeller, and the flow guider is equipped outside the first stage impeller, and the flow guider is supported at the water inlet body top, and the guide vane is installed outside each other stage impeller, and the support is formed between each stage guide vane and flow guider along the axial, the outer periphery of axial flow impeller is provided with the impeller cover, and the impeller cover is located at the first stage impeller import. The utility model improves the structure of axial flow impeller and surrounding, and the rim or cylinder is increased outside the impeller and covers the impeller, avoids the liquid after the pressure increase of axial flow impeller and escapes to all around, and the liquid is sent into the first stage impeller smoothly, and when the liquid level is low, still can normally operate, reduces the minimum immersion depth of pump inlet.

Description

Technical Field

[0001] This utility model relates to the field of pump products, and specifically to a structure for reducing the immersion depth of the inlet of an immersion pump. Background Technology

[0002] The pump inlet immersion depth refers to the minimum vertical distance from the lower end face of the pump suction inlet to the liquid surface in the pool. It is crucial for ensuring normal liquid intake and preventing gas entrapment or cavitation, and is one of the key parameters for safe pump operation. This depth needs to be determined based on the pump type, flow rate, and medium characteristics. Insufficient immersion depth may lead to air intake, vibration, decreased efficiency, or flow interruption, and may damage the pump; excessive immersion depth will increase equipment investment. For high-temperature or easily vaporized liquids, a greater depth is required to maintain sufficient net positive suction head (NPSH).

[0003] During operation, the water level in the liquid pool of a submersible pump is constantly changing. When the water level falls below the pump's minimum immersion depth, gas is carried into the pump, which can lead to failure of the pump's mechanical seal and sliding bearings, and pump flow interruption.

[0004] Some submersible pumps on the market have an axial flow impeller at the inlet. This impeller is installed at a low position, which theoretically reduces the minimum immersion depth of the submersible pump inlet and can reduce the damage caused by gas entering the pump when the liquid level is too low.

[0005] However, in the existing technology, the axial flow impeller has no rim or cylinder to cover the blades. During operation, the liquid flowing through the axial flow impeller moves upward and outward under the action of centrifugal force, making it difficult for the liquid to be sent into the first stage impeller. At the same time, since the axial flow impeller and the guide are open structures, the liquid pressurized by the axial flow impeller will quickly lose pressure, which greatly reduces the effect of the axial flow impeller in lifting the liquid. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a structure for reducing the immersion depth of the submersible pump inlet. It improves the structure of the axial impeller and its surroundings by adding a rim to the outside of the impeller or using a cylinder to cover the impeller, so as to prevent the liquid pressurized by the axial impeller from escaping to the surroundings and to smoothly send the liquid into the first-stage impeller. This allows the pump to operate normally even when the liquid level in the liquid pool is low, effectively reducing the minimum immersion depth of the pump inlet.

[0007] The purpose of this utility model is achieved through the following technical solution: This structure for reducing the immersion depth of an immersion pump inlet includes an inlet body, a guide vane, a pump shaft, and guide vanes. An axial flow impeller is installed on the pump shaft at the end away from the motor, and several stages of impellers are sequentially installed axially at the end of the pump shaft near the motor. The impeller facing the axial flow impeller is the first-stage impeller. A guide vane is provided outside the first-stage impeller and is supported on the top of the inlet body. Guide vanes are installed outside the other stages of impellers, and each stage of guide vane and the guide vane form axial support. An impeller sleeve is provided on the outer periphery of the axial flow impeller, and the impeller sleeve is located at the inlet of the first-stage impeller.

[0008] As a further technical solution, the impeller sleeve is made of a cylinder, which is fixed to the lower end face of the guide vane.

[0009] As a further technical solution, a radial gap is provided between the inner wall of the cylinder and the blade edge of the axial flow impeller.

[0010] As a further technical solution, the cylinder is welded or threaded to the flow guide.

[0011] As a further technical solution, the impeller sleeve and the blades of the axial flow impeller are integrally formed to form the rim of the axial flow impeller.

[0012] As a further technical solution, an axial gap is provided between the upper end face of the rim and the lower end face of the guide vane.

[0013] The beneficial effects of this utility model are as follows:

[0014] 1. Adding a rim to the outside of the axial impeller or using a cylindrical body to cover the impeller can effectively reduce or prevent the liquid in the inlet body from being rotated by the axial impeller, prevent the liquid level in the center of the inlet body from dropping, and thus reduce the immersion depth of the pump inlet.

[0015] 2. The axial impeller is covered by the cylinder (round cylinder) below the guide tube with guide tube. The radial clearance at this point is small, which reduces the pressure loss of the liquid at this point.

[0016] 3. The axial clearance between the upper end face of the rimmed axial flow impeller and the guide vane is small, which reduces the pressure relief of the liquid at this point. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model.

[0018] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this utility model.

[0019] Explanation of reference numerals in the attached drawings: 1. Axial flow impeller; 2. Inlet body; 3. First stage impeller; 4. Guide vane; 5. Pump shaft; 6. Guide vane; 7. Cylinder; 8. Impeller rim. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings:

[0021] Example 1: As shown in the attached document Figure 1 As shown, this structure for reducing the immersion depth of the submersible pump inlet includes an axial flow impeller 1, an inlet body 2, a first-stage impeller 3, a guide vane 4, a pump shaft 5, guide vanes 6, a cylinder 7, and a rim 8.

[0022] Reference Appendix Figure 1 One end of the pump shaft 5 is driven by a motor, and the other end of the pump shaft 5 (i.e., the end away from the motor) passes through guide vanes 6 and is fitted with an axial impeller 1. Several stages of impellers are sequentially installed axially on the pump shaft 5 (the end closest to the motor). The impeller facing the axial impeller 1 is the first-stage impeller 3, and a guide vane 4 is provided only on the outside of the first-stage impeller 3. An inlet body 2 is installed on the side of the pump away from the motor, and the guide vane 4 is supported on top of the inlet body 2. Guide vanes 6 are installed on the outside of all other impeller stages, and each stage of guide vane 6 is connected axially to the guide vane 4 (of the first-stage impeller 3) to form a support.

[0023] Furthermore, a cylinder 7 is provided on the outer periphery of the axial impeller 1 as an impeller sleeve (the impeller sleeve is located at the inlet of the first-stage impeller 3 below the guide vane 4). The cylinder 7 is fixed to the lower end face of the guide vane 4 by welding or threaded connection, forming a guide vane 4 with a guide cylinder. Preferably, a radial gap is provided between the inner wall of the cylinder 7 and the blade edge of the axial impeller 1 (i.e., the cylinder 7 does not contact the blade). This radial gap is small, reducing liquid pressure loss at this location.

[0024] The working process of this embodiment is as follows: The axial flow impeller 1 is covered by the cylinder 7 below the guide 4 to prevent the formation of a cavity in the central area of ​​the axial flow impeller 1 when the axial flow impeller 1 drives the liquid in the inlet body 2 to move, thus ensuring that the liquid is sent into the first stage impeller 3.

[0025] The axial impeller 1 is covered by the cylinder 7 below the guide vane 4 to prevent the liquid level in the inlet body 2 from dropping due to the rotation of the liquid around the axis caused by the axial impeller 1.

[0026] The axial impeller 1 is covered by the guide tube below the guide tube 4 to prevent the liquid after being pressurized by the axial impeller 1 from losing pressure and escaping, and to efficiently send the liquid into the first impeller 3, thereby improving the water lifting capacity of the axial impeller 1.

[0027] Example 2: As Figure 2 As shown, the difference from Embodiment 1 is that the impeller sleeve and the blades of the axial flow impeller 1 are integrally formed to form the rim 8 of the axial flow impeller 1. Furthermore, an axial gap is provided between the upper end face of the rim 8 and the lower end face of the guide vane 4, that is, the rim 8 and the guide vane 4 do not come into contact.

[0028] The working process of this embodiment is as follows: The outer side of the axial flow impeller 1 has a rim 8 to prevent the formation of a cavity in the central area of ​​the axial flow impeller 1 when the axial flow impeller 1 drives the liquid in the inlet body to move, thus ensuring that the liquid is sent into the first stage impeller 3.

[0029] The axial impeller 1 has a rim 8 on its outer side to prevent the liquid level in the inlet body 2 from dropping due to the rotation of the liquid around the axial axis caused by its blades.

[0030] The axial clearance between the upper end face of the rim 8 of the axial impeller 1 and the guide vane 4 is small, which prevents the liquid from being depressurized at this point after being pressurized by the axial impeller 1, and efficiently sends the liquid into the first impeller 3, thereby improving the water lifting capacity of the axial impeller 1.

[0031] It is understood that, for those skilled in the art, any equivalent substitutions or modifications to the technical solutions and inventive concepts of this utility model should fall within the protection scope of the appended claims.

Claims

1. A structure for reducing the immersion depth of an immersion pump inlet, characterized in that: The pump shaft (5) includes an inlet body (2), a guide vane (4), a pump shaft (5), and guide vanes (6). An axial flow impeller (1) is installed on the pump shaft (5) at the end away from the motor. Several stages of impellers are installed sequentially along the axial direction on the end of the pump shaft (5) near the motor. The impeller facing the axial flow impeller (1) is the first stage impeller (3). A guide vane (4) is provided outside the first stage impeller (3). The guide vane (4) is supported on the top of the inlet body (2). Guide vanes (6) are installed outside the other stages of impellers. A support is formed between the guide vanes (6) and the guide vane (4) along the axial direction. An impeller sleeve is provided on the outer periphery of the axial flow impeller (1). The impeller sleeve is located at the inlet of the first stage impeller (3).

2. The structure for reducing the immersion depth of an immersion pump inlet according to claim 1, characterized in that: The impeller sleeve is made of a cylinder (7), which is fixed to the lower end face of the guide (4).

3. The structure for reducing the immersion depth of an immersion pump inlet according to claim 2, characterized in that: A radial gap is provided between the inner wall of the cylinder (7) and the blade edge of the axial flow impeller (1).

4. The structure for reducing the immersion depth of an immersion pump inlet according to claim 2 or 3, characterized in that: The cylinder (7) is welded or threaded to the guide (4).

5. The structure for reducing the immersion depth of an immersion pump inlet according to claim 1, characterized in that: The impeller sleeve and the blades of the axial flow impeller (1) are integrally formed to form the rim (8) of the axial flow impeller (1).

6. The structure for reducing the immersion depth of an immersion pump inlet according to claim 5, characterized in that: An axial gap is provided between the upper end face of the rim (8) and the lower end face of the guide (4).

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