Connecting device for water suction pipe of water pump

Abstract

The utility model belongs to the technical field of water suction systems of water pumps, and discloses a connecting device for a water suction pipe of a water pump, which comprises a concentric reducing pipe, a convex pipeline elbow, a concave pipeline elbow, an exhaust structure and a water drainage structure, and is characterized in that one end of the convex pipeline elbow is connected with the water suction pipe, and the other end of the convex pipeline elbow is connected with a port with a larger outer diameter of the concentric reducing pipe; one end of the concave pipeline elbow is connected with a water suction port of the water pump, the other end of the concave pipeline elbow is connected with a port with a smaller outer diameter of the concentric reducing pipe, the exhaust structure is arranged at the convex pipeline elbow and used for exhausting gas at an inlet section of the water pump, and the drainage structure is arranged at the concave pipeline elbow and used for exhausting liquid in the water pump. The device has the advantages of being convenient to install, simple and stable in structure, capable of reducing cavitation damage of the water pump, improving the water absorption performance of the water pump, prolonging the service life of the water pump, and meanwhile facilitating overhaul emptying and slag removal of a unit.

Description

Technical Field

[0001] The utility model belongs to the technical field of water pump suction systems, and particularly relates to a connecting device for a water pump suction pipe. Background Art

[0002] The main function of a water pump is to input energy into the system, supplement the required mechanical energy, and be used for the transportation of fluids or the increase of pressure. Water pumps are widely used in engineering practices and various industries and are crucial for the normal operation of engineering and industrial production. The composition of a water pump system can generally be divided into three parts, namely a water pump suction system, a water pump unit, and a water pump discharge system.

[0003] This application mainly focuses on the water pump suction system. During the production and manufacturing of water pumps, due to the relatively small sizes of the water pump impeller and volute corresponding to the working conditions, the diameters of the water pump inlet and outlet are also relatively small. However, considering the allowable suction lift height of the water pump and the engineering installation height, the water pump suction pipe needs to adopt a relatively small flow rate and a relatively large pipe diameter to reduce the head loss generated in the suction pipe section. This makes it necessary to use a reducing pipe at the water pump inlet to connect the suction pipe and the water pump inlet. At the same time, due to the rapid increase in the fluid flow rate at the water pump inlet, the internal pressure of the water pump and the suction system drops sharply, resulting in the precipitation of the dissolved gas in the water. The precipitated gas will collapse due to the sudden increase in pressure at the end of the water pump impeller blade and near the hub, causing cavitation damage to the water pump unit impeller and volute. Therefore, there is an urgent need to design a pipeline connection structure for the water pump suction port to solve the above problems. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a connecting device for a water pump suction pipe, which can reduce the cavitation damage of the water pump, improve the water pump suction performance, extend the service life of the water pump, and at the same time facilitate the maintenance, evacuation, and slag cleaning of the unit.

[0005] The technical solution adopted by the utility model is a connecting device for a water pump suction pipe, which includes a concentric reducing pipe, a convex pipe elbow, a concave pipe elbow, an exhaust structure, and a drain structure. One end of the convex pipe elbow is connected to the suction pipe, and the other end is connected to the port with the larger outer diameter of the concentric reducing pipe. One end of the concave pipe elbow is connected to the water pump suction port, and the other end is connected to the port with the smaller outer diameter of the concentric reducing pipe. The exhaust structure is installed at the convex pipe elbow to discharge the gas in the water pump inlet section, and the drain structure is installed at the concave pipe elbow to discharge the liquid in the water pump.

[0006] Further, the exhaust structure includes a single-flange short pipe, a manual maintenance valve, and an air valve. The single-flange short pipe is connected to the convex pipe elbow, the manual maintenance valve is connected to the single-flange short pipe, and the air valve is connected to the manual maintenance valve. The air valve only has the function of exhausting gas.

[0007] Further, the water discharge structure includes a water discharge valve and a water discharge pipe. The water discharge pipe is connected to the concave pipe elbow, and the water discharge valve is installed on the water discharge pipe.

[0008] Further, the larger outer diameter port of the concentric reducer is higher than the smaller outer diameter port, and the rising slope i ≥ 0.005.

[0009] The beneficial effects of the present utility model are as follows:

[0010] 1. For the connection device of the water pump suction pipe in the present utility model, through the air valve with only the exhaust function at the high point of the system structure, it can automatically exhaust according to the gas situation in the pipeline, and can also be controlled in combination with the pressure gauge of the suction pipe. It can effectively reduce the gas entering the water pump from the gas separated in the inlet section of the water pump, which is beneficial to reducing the cavitation damage of the water pump, improving the water absorption performance of the water pump, ensuring the stable operation of the system, and prolonging the service life of the water pump;

[0011] 2. For the connection device of the water pump suction pipe in this application, the suction pipe and the water pump suction port are connected through an elbow and a concentric reducer, which has the advantages of convenient installation and symmetrical and uniform hydraulic conditions at the water pump inlet;

[0012] 3. For the connection device of the water pump suction pipe in this application, a water discharge valve is set at the local low point of the system at the water pump inlet, which has the advantages of facilitating maintenance and emptying the equipment for slag cleaning for the water pump unit during intermittent operation or shutdown for maintenance. Description of the Drawings

[0013] Figure 1 is the overall structure schematic diagram of the present utility model;

[0014] Figure 2 is the exhaust structure schematic diagram of the present utility model;

[0015] Figure 3 is the water discharge structure schematic diagram of the present utility model;

[0016] Description of the reference numerals: 1. Suction pipe; 2. Single flange short pipe; 3. Manual maintenance valve; 4. Air valve; 5. Convex pipe elbow; 6. Concentric reducer; 7. Water discharge valve; 8. Water discharge pipe; 9. Concave pipe elbow; 10. Water pump suction port. Detailed Embodiments

[0017] In order to make the purpose, technical solutions and advantages of the present utility model clearer and more understandable, the technical solutions of the present utility model will be further described in detail below with reference to the drawings.

[0018] As Figure 1 、 Figure 2 、 Figure 3As shown in the figure, a connecting device for a water pump suction pipe provided by the utility model includes a concentric reducer 6, a convex pipe elbow 5, a concave pipe elbow 9, an exhaust structure and a drain structure. One end of the convex pipe elbow 5 is connected to the suction pipe 1 and the other end is connected to the port with a larger outer diameter of the concentric reducer 6. One end of the concave pipe elbow 9 is connected to the water pump suction port 10 and the other end is connected to the port with a smaller outer diameter of the concentric reducer 6. The exhaust structure is installed at the convex pipe elbow 5 to discharge the gas in the inlet section of the water pump, and the drain structure is installed at the concave pipe elbow 9 to discharge the liquid in the water pump.

[0019] The concentric reducer 6 is arranged in an inclined shape, with its port having a larger outer diameter higher than the port having a smaller outer diameter, and the rising slope i≥0.005. Therefore, the higher end of the concentric reducer 6 needs to be connected to the suction pipe 1 through the convex pipe elbow 5, and the lower end of the concentric reducer 6 needs to be connected to the water pump suction port 10 through the concave pipe elbow 9. This connection method can avoid the formation of a large air bag, thereby preventing the air bag from entering the water pump and affecting the performance of the water pump. However, in the flow channel from the suction pipe 1 to the back of the water pump impeller, the continuously precipitated bubbles will still enter the water pump in a dispersed form and collapse due to pressure changes at the blade tips and hubs of the water pump impeller, causing cavitation damage to the water pump. Therefore, in the present utility model, an exhaust structure is installed at the convex pipe elbow 5 for exhausting gas, which can effectively reduce the gas precipitated in the inlet section of the water pump from entering the water pump, is beneficial to reducing cavitation damage of the water pump, improving the water absorption performance of the water pump, ensuring stable operation of the system, and extending the service life of the water pump.

[0020] Specifically, the exhaust structure includes a single flange short pipe 2, a manual maintenance valve 3 and an air valve 4. The single flange short pipe 2 is connected to the convex pipe elbow 5, the manual maintenance valve 3 is connected to the single flange short pipe 2, and the air valve 4 is connected to the manual maintenance valve 3. The air valve 4 only has the function of exhausting gas.

[0021] The air valve 4 only has the function of exhausting gas and is mainly composed of a control valve and a pressure reducing valve. The control valve is responsible for controlling the inlet and outlet of gas, while the pressure reducing valve plays a role in reducing gas pressure. A special structure-designed steam-water separation disc inside the valve body ensures that no water is drained during gas exhaust, and as long as the system has pressure, gas will be continuously exhausted.

[0022] During operation, the gas inhaled by the water pump suction port 10 or the gas precipitated due to a sudden drop in system pressure at the water pump inlet will gather towards the highest point of the system, i.e., the convex pipe elbow 5. Then, the gas will enter the valve cavity of the air valve 4 through the flange short pipe 2 and gather at the upper part of the air valve 4. As the gas increases, the pressure inside the valve rises, causing the water level inside the valve to drop. The float inside the valve drops with the water level, thus opening the exhaust port to exhaust gas. When all the gas is exhausted, the water level inside the valve rises again, and the float inside the valve also rises to close the exhaust port, so as to ensure that the system only exhausts gas without draining water.

[0023] This design can discharge a large amount of air in the pipeline and a small amount of gas generated during system operation to the outside air at high speed through the air valve 4, and it is also convenient for maintenance. When installing the air valve, a hole is opened in the convex pipeline elbow 5 and a single-flange short pipe 2 is directly welded. The single-flange short pipe 2, the manual maintenance valve 3 and the air valve 4 are all connected by flanges. The manual maintenance valve 3 is mainly for the convenience of maintaining the air valve 4. During operation, the manual maintenance valve 3 is an always-open device.

[0024] The drainage structure includes a drain valve 7 and a drain pipe 8. The drain pipe 8 is connected to the concave pipeline elbow 9, and the drain valve 7 is installed on the drain pipe 8.

[0025] The concave pipeline elbow 9 connected to the water pump inlet is the lowest point of the system. At this point, a hole is also opened through the elbow, and the drain pipe 8 is connected by welding. The drain valve 7 is connected to the drain pipe 8 by flanges. During operation, the drain valve 7 is a normally closed valve. When the system is shut down or under maintenance conditions, the stored water in the water absorption system can be discharged through the drain valve 7, which is convenient for maintenance. This is more important for the water pump unit with intermittent operation. When encountering the working condition of transporting water containing sand, the drain valve 7 also has the function of regularly emptying the accumulated sand in the water absorption system and flushing and draining the impeller.

[0026] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

Claims

1. A connecting device for a water pump suction pipe, characterized in that: It includes a concentric reducer, a convex pipe elbow, a concave pipe elbow, an exhaust structure and a drain structure. One end of the convex pipe elbow is connected to the water suction pipe and the other end is connected to the port with a larger outer diameter of the concentric reducer. One end of the concave pipe elbow is connected to the water suction port of the water pump and the other end is connected to the port with a smaller outer diameter of the concentric reducer. The exhaust structure is installed at the convex pipe elbow to discharge the gas in the inlet section of the water pump, and the drain structure is installed at the concave pipe elbow to discharge the liquid in the water pump.

2. The connecting device for a water pump suction pipe according to claim 1, characterized in that: The exhaust structure includes a single flange short pipe, a manual inspection valve and an air valve. The single flange short pipe is connected to a convex pipe elbow, the manual inspection valve is connected to the single flange short pipe, the air valve is connected to the manual inspection valve, and the air valve has only an exhaust function.

3. The connecting device for a water pump suction pipe according to claim 1, characterized in that: The water discharge structure comprises a water discharge valve and a water discharge pipe. The water discharge pipe is connected to the concave pipe elbow, and the water discharge valve is installed on the water discharge pipe.

4. The connecting device for a water pump suction pipe according to claim 1, characterized in that: The larger outer diameter port of the concentric reducer is higher than the smaller outer diameter port and the rising slope i is greater than or equal to 0.005.

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