A centrifugal pump self-priming device

Abstract

The invention discloses a self-priming device for a centrifugal pump, comprising a self-priming device and a centrifugal pump. The self-priming device comprises an inlet section, an outlet section, a water return pipe and a nozzle. The inlet section is in an S-tube shape, the upper end of the inlet section is connected to a water inlet pipeline, and the lower end is connected to the inlet of the centrifugal pump. A nozzle is arranged inside the inlet section, and the outlet of the nozzle points to the inlet of the centrifugal pump. An interface for connecting to the water return pipe is arranged outside the inlet section. The outlet section is in a straight tube shape, and the outlet section is located above the centrifugal pump, the upper end of the outlet section is connected to the water outlet pipeline, and the lower end is connected to the outlet of the centrifugal pump. An interface for connecting to the water return pipe is arranged outside the outlet section, and the inlet section and the outlet section are connected through the water return pipe. The invention enables an ordinary centrifugal pump to have a self-priming function by adding a self-priming device to the ordinary centrifugal pump. The pump only needs to be primed before the first start-up, and the pump is easy to install and can be used immediately after being turned on. After normal operation, the reflux valve is closed. Since the main pump is a centrifugal pump, the operation efficiency is high, the structure is simple, the processing is easy, and the use is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal pumps, in particular to a self-priming device for a centrifugal pump. Background Art

[0002] Ordinary centrifugal pumps do not have a self-priming function. To ensure the normal operation of the centrifugal pump, the water inlet pipe and the pump need to be filled with liquid. When the impeller is higher than the suction liquid level, the commonly used methods are: each time the forward pump is started and the water inlet pipe is filled with liquid, which increases the workload and the start-up time, and is not conducive to remote automatic control, which is very inconvenient. Install a bottom valve at the inlet of the water inlet pipe, but the bottom valve will cause a large hydraulic loss, and there is a situation where the seal is not firm and leaks. Use a vacuum pump to discharge the gas in the water inlet pipe and the pump. This method has high equipment cost, complex operation, and a large maintenance workload.

[0003] The self-priming pump is designed and improved in structure, so that it only needs to be filled with water before the first start, and the water inlet pipe does not need to be filled with water. The pump itself can automatically discharge the gas in the water inlet pipe, so as to enter normal operation. At present, the gas-liquid mixing self-priming pump is mostly used, which is divided into two types: internal mixing type and external mixing type. Its working principle is that a certain amount of water is first stored in the pump. After the pump is started, due to the rotation of the impeller, the air and water in the water inlet pipe are fully mixed and discharged to the gas-water separation chamber. The gas in the upper part of the gas-water separation chamber is discharged, and the liquid in the lower part returns to the impeller and mixes with the gas in the water inlet pipe until all the gas in the pump and the water inlet pipe is discharged, completing the self-priming process. The internal mixing self-priming pump is divided into an injection device and a non-injection device. Among them, the internal mixing self-priming pump with an injection device has the advantages of fast water supply and high suction range.

[0004] Since the gas-liquid mixing self-priming pump's gas-liquid separation chamber, vortex chamber, suction chamber, and reflux device are integrally formed, the pump has a complex structure, is difficult to process, is bulky, and has high cost. In order to achieve the gas-water mixing and gas-water separation functions, the pump's flow channel and fluid mechanics model are changed. Therefore, the efficiency of the self-priming pump is much lower than that of an ordinary centrifugal pump. Summary of the invention

[0005] The purpose of the present invention is to solve the problem in the prior art that centrifugal pumps cannot be self-priming and the efficiency of self-priming pumps is low.

[0006] In order to solve the problems existing in the prior art, the present invention provides a centrifugal pump self-priming device, which enables an ordinary centrifugal pump to have a self-priming function. Specifically, the centrifugal pump self-priming device includes a self-priming device and a centrifugal pump. The self-priming device and the interest pump are installed together.

[0007] The self-priming device comprises an inlet section, an outlet section, a return pipe and a nozzle. The inlet section is in an S-tube shape. The upper end of the inlet section is connected to the water inlet pipeline, and the lower end of the inlet section is connected to the inlet of the centrifugal pump.

[0008] The inlet section is provided with a nozzle inside, the outlet of the nozzle points to the inlet of the centrifugal pump, and the inlet section is provided with an interface for connecting to a return pipe outside.

[0009] The outlet section is a straight pipe type, and the outlet section is located above the centrifugal pump. The upper end of the outlet section is connected to the water outlet pipeline, and the lower end of the outlet section is connected to the outlet of the centrifugal pump. An interface for connecting to a return pipe is provided on the outside of the outlet section, and the inlet section and the outlet section are connected through the return pipe.

[0010] Furthermore, a reflux valve is provided on the return water pipeline.

[0011] Furthermore, the reflux valve is in an open state when the pressure difference is less than a critical value, and is in a closed state when the pressure difference is greater than the critical value, and the critical value is between the self-priming height and the head of the centrifugal pump during operation.

[0012] Furthermore, the reflux valve is an elastic reflux valve, and the reflux valve includes a valve flap, a valve seat, a guide rod, a guide frame and a spring.

[0013] Furthermore, the spring is always in a compressed state during operation, and the size of the opening and closing critical value of the reflux valve is controlled by changing the size of the spring elastic force.

[0014] Furthermore, the nozzle and the inlet section are integrally formed.

[0015] Furthermore, the nozzle is detachably connected to the inlet section.

[0016] Furthermore, the cross section of the nozzle is circular, elliptical, waist-shaped or rectangular, and the nozzle opening includes one or more.

[0017] Furthermore, a water filling hole is provided at the top of the inlet section, and the height of the inlet centerline of the inlet section is higher than the height of the outlet flange surface of the centrifugal pump or is equal to the height of the outlet flange surface of the centrifugal pump.

[0018] Furthermore, the outlet section is composed of an inner tube and an outer shell, the area between the inner tube and the outer shell is a gas-liquid separation chamber, a window is provided on the inner tube, and the area inside the inner tube is connected to the gas-liquid separation chamber through the window.

[0019] The beneficial effects of the present invention are as follows: (1) The present invention provides a centrifugal pump self-priming device with a simple structure and convenient processing; (2) It is easy to install and can be used in conjunction with a centrifugal pump to enable the centrifugal pump to have a self-priming function. It only needs to inject water into the pump through the S-bend pipe before the first start-up, and there is no need to inject water every time, which is convenient to use; (3) When the centrifugal pump is working normally, the reflux valve is automatically closed due to the pressure difference, and the efficiency is high; (4) The nozzle is detachable and can be replaced with nozzles of different sizes, shapes and numbers according to the parameters of the centrifugal pump and the usage conditions, so as to change the self-priming time and self-priming height, and the application range is wide; (5) For use occasions with self-priming requirements, there is no need to modify or replace the original centrifugal pump, and only the self-priming device needs to be configured to meet the requirements. The configuration is flexible, the inheritance is good, and the waste of resources is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a centrifugal pump self-priming device embodiment 1 of the present invention;

[0021] Figure 2 It is a partial enlarged view of the reflux valve of the centrifugal pump self-priming device embodiment 1 of the present invention;

[0022] Figure 3 is a perspective view of a centrifugal pump self-priming device embodiment 1 of the present invention;

[0023] Figure 4 It is a schematic diagram of Example 2 of the centrifugal pump self-priming device of the present invention.

[0024] In the figure: 1-inlet, 2-outlet section, 2.1-inner tube, 2.2-outer shell, 2.3-window, 2.4-gas-liquid separation chamber, 3-return pipe, 4-return valve, 4.1-valve disc, 4.2-valve seat, 4.3-spring, 4.4-guide rod, 4.5-guide frame, 5-nozzle, 6-water filling hole plug, 7-impeller, 8-pump body, 9-pump cover, 10-bracket, 11-motor. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Example 1: Figure 1 and Figure 2 As shown, the centrifugal pump self-priming device of the present invention includes a self-priming device and a centrifugal pump, wherein the self-priming device and the centrifugal pump are separate and need to be installed for use together, wherein the self-priming device includes an inlet section 1, an outlet section 2, a return pipe 3 and a nozzle 5.

[0027] The inlet section 1 is in an S-tube shape, the upper end of the inlet section 1 is connected to the water inlet pipeline, and the lower end of the inlet section 1 is connected to the inlet of the centrifugal pump. A nozzle 5 is arranged inside the inlet section 1, and the outlet of the nozzle 5 points to the inlet of the centrifugal pump. The outside of the inlet section 1 is provided with an interface connected to the return pipe 3.

[0028] The outlet section 2 is a straight pipe type, and the outlet section 2 is located above the centrifugal pump. The upper end of the outlet section 2 is connected to the water outlet pipeline, and the lower end of the outlet section 2 is connected to the centrifugal pump outlet. The outlet section 2 is provided with an interface for connecting to the return pipe 3 on the outside. The inlet section 1 and the outlet section 2 are connected through the return pipe 3.

[0029] The centrifugal pump is mainly composed of an impeller 7 , a pump body 8 , a pump cover 9 , a bracket 10 and a motor 11 .

[0030] Furthermore, a reflux valve 4 is installed on the return pipe 3, and the reflux valve 4 is in an open state when the pressure difference is less than 15m, and is in a closed state when the pressure difference is greater than 15m. The head of the working range of the centrifugal pump is greater than 30m.

[0031] The reflux valve 4 is an elastic reflux valve, specifically, Figure 2 As shown, the return valve 4 comprises a valve flap 4.1, a valve seat 4.2, a guide rod 4.4, a guide frame 4.5 and a spring 4.3.

[0032] During the working process, the spring 4.3 is always in a compressed state, and the spring pressure is 33N when the return valve 4 is closed.

[0033] The nozzle 5 is integrally formed with the inlet section 1, and the nozzle 5 cannot be disassembled. The nozzle cross section is circular, and there is only one nozzle opening.

[0034] A water filling hole is arranged at the top of the inlet section 1, and a plug 6 is installed on the water filling hole. The inlet centerline height of the inlet section 1 is higher than the outlet flange surface height of the centrifugal pump.

[0035] The outlet section 2 is composed of an inner tube 2.1 and an outer shell 2.2. The area between the inner tube 2.1 and the outer shell 2.2 is a gas-liquid separation chamber 2.4. A window 2.3 is provided on the inner tube 2.1 to connect the area inside the inner tube 2.1 with the gas-liquid separation chamber 2.4.

[0036] Example 2: Figure 3 As shown, the centrifugal pump self-priming device of the present invention comprises a self-priming device and a centrifugal pump, wherein the self-priming device and the centrifugal pump are separate and need to be installed together for use.

[0037] The self-priming device comprises an inlet section 1 , an outlet section 2 , a return pipe 3 and a nozzle 5 .

[0038] The inlet section 1 is in an S-tube shape, the upper end of the inlet section 1 is connected to the water inlet pipeline, and the lower end of the inlet section 1 is connected to the inlet of the centrifugal pump. A nozzle 5 is arranged inside the inlet section 1, and the outlet of the nozzle 5 points to the inlet of the centrifugal pump. The outside of the inlet section 1 is provided with an interface connected to the return pipe 3.

[0039] The outlet section 2 is a straight pipe type, and the outlet section 2 is located above the centrifugal pump. The upper end of the outlet section 2 is connected to the water outlet pipeline, and the lower end of the outlet section 2 is connected to the centrifugal pump outlet. The outlet section 2 is provided with an interface for connecting to the return pipe 3 on the outside. The inlet section 1 and the outlet section 2 are connected through the return pipe 3.

[0040] The centrifugal pump is mainly composed of an impeller 7 , a pump body 8 , a pump cover 9 , a bracket 10 and a motor 11 .

[0041] A reflux valve 4 is also installed on the return water pipeline 3. The reflux valve 4 is in an open state when the pressure difference is less than 20m, and is in a closed state when the pressure difference is greater than 20m. The head of the centrifugal pump working area is greater than 30m.

[0042] The return valve 4 is an elastic return valve, which mainly comprises a valve flap 4.1, a valve seat 4.2, a guide rod 4.4, a guide frame 4.5 and a spring 4.3.

[0043] The spring 4.3 is always in a compressed state during operation. When the return valve 4 is closed, the spring pressure is 44N.

[0044] The nozzle 5 is a separate component from the inlet section 1, and the nozzle 5 is detachable. The nozzle cross section is circular, and there are two nozzle openings.

[0045] A water filling hole is arranged at the top of the inlet section 1, and a plug 6 is installed on the water filling hole. The inlet centerline height of the inlet section 1 is higher than the outlet flange surface height of the centrifugal pump.

[0046] The outlet section 2 is composed of an inner tube 2.1 and an outer shell 2.2. The area between the inner tube 2.1 and the outer shell 2.2 is a gas-liquid separation chamber 2.4. A window 2.3 is provided on the inner tube 2.1 to connect the area inside the inner tube 2.1 with the gas-liquid separation chamber 2.4.

[0047] The working principle of the centrifugal pump self-priming device of the present invention is as follows: before the pump is started, water is poured into the pump through the water filling hole on the inlet section 1 until the liquid level reaches the inlet of the inlet section 1. After the pump is started, the impeller 7 rotates at a high speed, and a negative pressure is formed at the impeller inlet, and the outlet of the inlet pipe 1 and the nozzle 5 are in a vacuum state. The air in the water inlet pipe is sucked into the inlet section 1, mixed with the water in the inlet section 1, and enters the impeller 7, and is discharged to the outlet section 2 through the pump body 8. The gas-liquid mixture in the inner tube 2.1 of the outlet section will enter the gas-liquid separation chamber 2.4 through the window 2.3. As the cross-sectional area of ​​the gas-liquid separation chamber becomes larger and the flow rate decreases, the gas-liquid separation is achieved by utilizing the difference in density between gas and liquid, and the gas is discharged upward from the outlet of the outlet section 2. The liquid remains in the lower part of the gas-liquid separation chamber, and under the action of the pressure difference, it reaches the nozzle 5 through the reflux pipe 3 and the reflux valve 4, forming a high-speed jet, carrying the gas in the inlet section 1, and returning to the impeller. This is repeated until all the air in the pump and the inlet pipeline is exhausted, and self-priming is completed.

[0048] During the self-priming process, the pressure difference between the two ends of the reflux valve 4 is small, and the reflux valve 4 is in an open state. During normal operation, the pressure of the gas-liquid separation chamber 2.4 increases, the pressure difference between the two ends of the reflux valve 4 increases, and the reflux valve 4 is closed, which reduces the volume loss and improves the efficiency of the pump. The nozzle in Example 2 can be disassembled, and nozzles of different sizes, shapes and numbers can be replaced according to the parameters and usage of the centrifugal pump, so as to change the self-priming time and self-priming height, expand the scope of application of the self-priming device, and meet different needs.

[0049] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A centrifugal pump self-priming device, comprising a self-priming device and a centrifugal pump, wherein the self-priming device and the centrifugal pump are installed and used together, characterized in that: The self-priming device comprises an inlet section, an outlet section, a return pipe, an automatic return valve and a nozzle. The inlet section is in an S-tube shape. The upper end of the inlet section is connected to the water inlet pipeline, and the lower end of the inlet section is connected to the inlet of the centrifugal pump. A nozzle is arranged inside the inlet section, and the outlet of the nozzle points to the inlet of the centrifugal pump. The outside of the inlet section is provided with an interface for connecting the return pipe. The outlet section is a straight pipe type, and the outlet section is located above the centrifugal pump. The upper end of the outlet section is connected to the water outlet pipeline, and the lower end of the outlet section is connected to the outlet of the centrifugal pump. The outlet section is provided with an interface for connecting a return pipe on the outside, and the inlet section and the outlet section are connected through a return pipe. A reflux valve is provided on the return pipe. When the centrifugal pump is working normally, the reflux valve is automatically closed due to the pressure difference. The reflux valve is in an open state when the pressure difference is less than a critical value, and is in a closed state when the pressure difference is greater than the critical value. The critical value is between the self-priming height and the head of the centrifugal pump during operation. The return valve is an elastic return valve, which includes a valve flap, a valve seat, a guide rod, a guide frame and a spring. The spring is always in a compressed state during operation, and the critical value of the opening and closing of the reflux valve is controlled by changing the elastic force of the spring. The outlet section is composed of an inner tube and an outer shell, the area between the inner tube and the outer shell is a gas-liquid separation chamber, a window is provided on the inner tube, and the area inside the inner tube is connected with the gas-liquid separation chamber through the window.

2. The centrifugal pump self-priming device according to claim 1, characterized in that: The nozzle is integrally formed with the inlet section.

3. The centrifugal pump self-priming device according to claim 1, characterized in that: The nozzle is detachably connected to the inlet section.

4. The centrifugal pump self-priming device according to claim 3, characterized in that: The cross section of the nozzle is circular, elliptical, waist-shaped or rectangular, and the nozzle includes one or more nozzles.

5. The centrifugal pump self-priming device according to claim 1, characterized in that: A water filling hole is arranged at the top of the inlet section, and the height of the inlet centerline of the inlet section is higher than the height of the outlet flange surface of the centrifugal pump or is equal to the height of the outlet flange surface of the centrifugal pump.

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