Multi-stage self-priming centrifugal pump volute cover and multi-stage self-priming centrifugal pump

Abstract

The utility model relates to the technical field of centrifugal pumps, and discloses a multi-stage self-priming centrifugal pump volute cover and a multi-stage self-priming centrifugal pump, a water return hole is additionally arranged on a first-stage impeller volute cover of the multi-stage self-priming centrifugal pump, and the water return hole is arranged near the lower edge of a first-stage impeller and is a certain distance away from the outer edge of the diameter of the impeller. Fluid in the gas-liquid separation chamber can partially flow back to the periphery of the first-stage impeller through the water return hole, it is guaranteed that the front-stage impeller does not lack water under the ideal condition, fluid in a runner of each stage of impeller can be basically continued without interruption, and air in the water inlet pipe can rapidly pass through each stage of impeller with the fluid as a carrier and then is separated and discharged. And the self-absorption water feeding time of the pump is shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of centrifugal pumps, in particular to a volute cover of a multi-stage self-priming centrifugal pump and a multi-stage self-priming centrifugal pump. Background Art

[0002] Currently, gasoline-powered multi-stage self-priming centrifugal pumps utilize multiple (often two) single-suction, closed impellers connected in series, with each impeller forming a stage. Guide vanes connect the impellers at each stage, and a volute cover overlays the vanes, separating the pump's liquid storage chamber from the gas-liquid separation chamber. When the pump is operating, water (hereinafter referred to as "fluid") is discharged from the primary impeller, passes through the guide vanes, and enters the second-stage impeller, where it is then discharged. This process continues in this order. The greater the number of impeller stages, the higher the head. Due to this high head, these pumps are often referred to as high-head pumps.

[0003] When a multi-stage self-priming centrifugal pump is self-priming, due to the effect of atmospheric pressure, the primary impeller rotates to "suck in" the fluid in the liquid storage chamber from the suction port in the center of the volute cover and mix it with the gas in the water inlet pipe before being discharged. The fluid enters the inlet of the second-stage impeller through the guide vane and is then discharged from the second-stage impeller. This continues. After the fluid from the last-stage impeller is discharged into the gas-liquid separation chamber, the gas separates from the fluid and overflows upward from the water outlet of the pump body. This process is repeated until the air in the water inlet pipe is completely discharged and normal water delivery begins.

[0004] The air in the water inlet pipe needs to use fluid as a carrier to complete the exhaust process. During the self-priming process, the fluid needs to pass through multiple stages of impellers and can only separate from the guide vanes at the last stage for gas-liquid separation. Compared with a single-stage centrifugal pump that only needs to pass through one stage of impeller, it takes longer. At the same time, due to the limited volume of the fluid in the liquid storage chamber, after the primary impeller sucks away the fluid, if it is not replenished in time, the fluid in the liquid storage chamber will be quickly consumed, and the primary impeller will basically be in a state of water shortage and idling. Only when some water in the gaps on the side of the impeller and the guide vanes slowly flows back to surround the primary impeller, the impeller will briefly resume suction, but it will soon be interrupted again. In this way, the primary impeller will not work continuously, resulting in a long self-priming time of the pump and a poor user experience. Utility Model Content

[0005] The utility model is intended to provide a volute cover for a multi-stage self-priming centrifugal pump, so as to solve the problem of the existing multi-stage self-priming centrifugal pump that after the primary impeller sucks away the fluid, if it is not replenished in time, the fluid in the liquid storage chamber is quickly consumed, the primary impeller is basically in a state of idling due to lack of water, the primary impeller works discontinuously, and the self-priming time of the pump is long.

[0006] To achieve the above purpose, the utility model adopts the following technical solution: a multi-stage self-priming centrifugal pump volute cover, which is provided with a return water structure, which is used to return the fluid on the outside of the volute cover to the primary impeller on the inside of the volute cover.

[0007] Preferably, as an improvement, the water return structure is one of a round hole, a square hole, an elliptical hole, a waist-round hole or a special-shaped hole.

[0008] Preferably, as an improvement, the water return structure is a valve that conducts one-way toward the inner side of the volute cover.

[0009] Preferably, as an improvement, after being assembled on the multi-stage self-priming centrifugal pump, the water return structure is located below the volute cover.

[0010] The principles and advantages of this solution are as follows: In actual application, the volute cover serves as a partition between the primary impeller and the gas-liquid separation chamber and liquid storage chamber. A fluid inlet is provided in the middle of the volute cover for fluid to enter the primary impeller. A return hole is provided on the outer side of the fluid inlet to provide additional fluid access to the primary impeller. Due to the limited fluid volume in the liquid storage chamber, if the primary impeller draws away fluid and cannot replenish it in time, fluid enters the primary impeller through the return hole as a supplement, preventing the primary impeller from idling due to water shortage, thereby ensuring continuous and effective operation of the primary impeller and shortening the self-priming time of the pump. This solution has a simple structure, stable and reliable operation, and significantly improves the self-priming performance of the pump.

[0011] A multi-stage self-priming centrifugal pump includes multiple stages of impellers connected in series. The impellers at each stage are connected through guide vanes. The guide vanes are equipped with a volute cover covering the outer side of the primary impeller. The volute cover uses the volute cover of the multi-stage self-priming centrifugal pump described above.

[0012] The multi-stage self-priming centrifugal pump of this scheme adds a return water hole on the volute cover outside the primary impeller. When working, the return water hole is located near the lower edge of the primary impeller and at a certain distance from the outer edge of the primary impeller diameter. Due to the existence of the return water hole, the fluid in the gas-liquid separation chamber can partially flow back to the periphery of the primary impeller through the return water hole, ensuring that the front-stage impeller is not short of water, so that the flow path of the impellers of each stage can be basically continuous without interruption. The air in the water inlet pipe can quickly pass through the impellers of each stage with the help of the fluid as a carrier, and then be separated and discharged, thereby shortening the self-priming water filling time of the pump.

[0013] According to a set of actual measurements, before the improvement, the self-priming time at 5 meters was 182 seconds, and the maximum self-priming altitude was 6 meters. After the improvement, the self-priming time at 5 meters was 69 seconds, the self-priming time at 6 meters was 112 seconds, and the maximum self-priming altitude was 7 meters. The self-priming time was significantly shortened, and the self-priming altitude was also greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of Example 1 of the present utility model.

[0015] Figure 2 It is a longitudinal sectional view of embodiment 1 of the present utility model.

[0016] Figure 3 It is a longitudinal sectional view of embodiment 3 of the present utility model. DETAILED DESCRIPTION

[0017] The following is further described in detail through specific implementation methods:

[0018] The figure marks in the drawings of the specification include: pump base 1, pump shaft 2, fluid inlet 3, secondary impeller 5, guide vane 6, primary impeller 7, volute cover 8, pump casing 9, water inlet 12, suction valve 13, sealing ring 14, liquid storage chamber A, gas-liquid separation chamber B, return water hole I.

[0019] Example 1, basically as in the attached Figure 1 、 Figure 2 As shown: A multi-stage self-priming centrifugal pump volute cover includes a circular cover plate with an annular side plate integrally formed along the circumference of the outer side of the cover plate. A fluid inlet 3 is opened in the middle of the cover plate, and a return hole I is opened on the cover plate outside the fluid inlet 3 as a return structure. In this embodiment, the return hole I is a circular hole, but is not limited to a circular hole. It can also be a square hole, an elliptical hole, a waist-round hole, a special-shaped hole, or other shapes. The return hole I is used to allow fluid outside the volute cover 8 to flow back to the primary impeller 7 inside the volute cover 8. After being assembled on the multi-stage self-priming centrifugal pump, the return hole I is located below the gas-liquid separation chamber B, so that the fluid in the gas-liquid separation chamber B can be replenished to the primary impeller 7 through the return hole I under the pressure difference and gravity. This embodiment is suitable for self-priming centrifugal pumps such as those in which the multi-stage impeller is rotatably arranged within the guide vane 6. The fluid sucked into the guide vane 6 is discharged by rotating the impeller.

[0020] Example 2, as an improvement, differs from Example 1 in that the return water structure in this embodiment is a valve that conducts one-way flow toward the inner side of the volute cover 8. The position of the valve is the same as that in Example 1. During the self-priming stage, the valve is open. After self-priming is completed, the valve is closed.

[0021] Example 3, basically as in the attached Figure 3 The present invention shows a multi-stage self-priming centrifugal pump, comprising a pump base 1 and a pump casing 9. Two stages of impellers are mounted on the pump base 1 via a pump shaft 2. A primary impeller 7 and a secondary impeller 5 are connected via guide vanes 6. The guide vanes 6 are provided with a volute cover 8 that covers the outside of the primary impeller 7. A rubber seal 14 is provided between the volute cover 8 and the guide vanes 6 to form a primary impeller 7 cavity in which the primary impeller 7 moves. The volute cover 8 uses the volute cover 8 of a multi-stage self-priming centrifugal pump of Example 1. The pump casing 9 is bolted to the pump base 1 to cover the volute cover 8. The pump casing 9 is provided with a liquid storage chamber A in the middle and a gas-liquid separation chamber B on the outside. A water inlet 12 is provided at one end of the liquid storage chamber A, and a suction valve 13 is installed in the water inlet 12. The other end of the liquid storage chamber A is connected to the fluid inlet 3 on the volute cover 8 and is sealed by a rubber seal 14. A water return hole 1 on the volute cover 8 connects the gas-liquid separation chamber B with the cavity of the primary impeller 7.

[0022] The specific implementation process is as follows: Fluid in gas-liquid separation chamber B cannot flow back through volute cover 8 toward the vicinity of primary impeller 7. When the pump is operating, the impeller rotates driven by the drive shaft, while the other components remain stationary. Fluid flows in through water inlet 12, flows in the direction of the arrow, and exits through the water outlet.

[0023] Before the pump self-primes, the pump's interior, including the liquid reservoir A and the gas-liquid separation chamber B, is completely filled with fluid. When the driver is activated, the pump begins self-priming. Due to atmospheric pressure, the primary impeller 7 rotates, drawing fluid from the liquid reservoir A and gas from the water inlet line through the suction port at the center of the volute cover 8. These fluids then flow in the direction indicated by the arrows, into the inlet of the secondary impeller 5, and out through the outlet of the guide vanes 6 into the gas-liquid separation chamber B. After separation, the gas overflows from the water outlet of the pump body. This cycle repeats until the air in the water inlet line is completely exhausted and normal water delivery begins. In this embodiment, the driver can be a gasoline engine, a diesel engine, or an electric motor.

[0024] Because the fluid volume of the liquid storage chamber A is limited during the self-priming stage, the fluid in the liquid storage chamber A will be quickly consumed after the primary impeller 7 sucks away the fluid, and the fluid in the gas-liquid separation chamber B cannot flow back to the vicinity of the primary impeller 7 through the volute cover 8. The primary impeller 7 will basically be in an idling state. Only when the fluid in the side gap of the primary impeller 7 and the fluid in the guide vane 6 that has not been sucked away by the secondary impeller 5 slowly flow back to surround the primary impeller 7, the primary impeller 7 will briefly resume suction, but it will soon be interrupted again. This will repeat, and the primary impeller 7 will work discontinuously, resulting in a long self-priming and water filling time of the pump, and it cannot be quickly put into normal water delivery operation. During this process, the temperature of the pump and the fluid will rise, which will have an adverse effect on the mechanical seal, etc.

[0025] In this embodiment, a circular return hole I is added to the volute cover 8, located a certain distance from the outer diameter of the primary impeller 7. When assembled, the volute cover 8 is positioned vertically directly below the primary impeller 7. This allows the fluid in the reservoir A to flow into the volute cover 8 for replenishment due to the pressure differential and gravity. During self-priming, this alleviates the water shortage in the primary impeller 7, ensuring more continuous and efficient self-priming operation and significantly shortening the self-priming time.

[0026] According to a set of actual measurements, the self-priming time at 5 meters was 182 seconds before the improvement, and the maximum self-priming altitude was 6 meters. After the improvement, the self-priming time at 5 meters was 69 seconds, the self-priming time at 6 meters was 112 seconds, and the maximum self-priming altitude was 7 meters. The self-priming time was significantly shortened after the improvement, and the self-priming altitude was also greatly improved.

[0027] The above description is merely an embodiment of the present invention, and the commonly known specific technical solutions and / or features of the solution are not described in detail here. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be considered as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection claimed in this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A volute cover of a multi-stage self-priming centrifugal pump, characterized by: A return water structure is provided on it, which is used to allow the fluid on the outside of the volute cover to flow back to the primary impeller on the inside of the volute cover. After being assembled on the multi-stage self-priming centrifugal pump, the return water structure is located below the volute cover; the return water structure is one of a round hole, a square hole, an elliptical hole, a waist-round hole or an irregular hole, or the return water structure is a valve that conducts one-way to the inside of the volute cover.

2. A multi-stage self-priming centrifugal pump comprising multiple stages of impellers connected in series, wherein the impellers at each stage are connected via guide vanes, and wherein: The guide vane is equipped with a volute cover covering the outer side of the primary impeller. The volute cover is a volute cover of a multi-stage self-priming centrifugal pump as claimed in claim 1.

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