Autonomous exhaust type low-cavitation double suction pump

Abstract

The utility model relates to the field of centrifugal pumps, in particular to an automatic exhaust type low-cavitation double suction pump which comprises a motor, a pump body in transmission connection with the motor and an air ejector. The controller is in communication connection with the motor, the pressure module is used for detecting the pressure of a liquid outlet of the pump body, the venturi tube is located on the outer side of the pump body, a negative pressure opening of the venturi tube is connected with an exhaust opening formed in the top of the pump body through an exhaust pipe, and a positive pressure inlet of the venturi tube is connected with a pressure air source through an air inlet pipe. A positive pressure outlet of the venturi tube is connected with the atmosphere, an air inlet valve is installed on the air inlet pipe, an air suction valve is installed on the exhaust pipe, and the air inlet valve and the air suction valve are in communication connection with a pressure module through a controller. And normal operation of the pump is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of split-case centrifugal pumps, in particular to a self-exhausting low-cavitation double-suction pump. Background Art

[0002] As an important form of centrifugal pumps, double-suction pumps are widely used in engineering due to their high head and large flow rate. The inlet and outlet of the double-suction pump adopt a side-in and side-out structure, and the size is relatively large. When the liquid level of the transported medium is lower than the double-suction pump, the pump body chamber cannot be filled with the medium, and the pump cannot operate normally. Only an additional vacuum unit is required to discharge the air in the pump body chamber. After the on-site personnel observe that the air is exhausted, they notify the operator to manually start the pump. The whole process is cumbersome to operate, and the cost of the vacuum unit is high, and it occupies a large space. At the same time, in the area from the liquid inlet of the traditional double-suction pump to the impeller suction port, vortex phenomena are likely to occur, resulting in relatively large cavitation and limited suction capacity. When the required net positive suction head generated exceeds the required net positive suction head of the pump, the pump will cavitate, reducing the service life of the impeller. Summary of the Utility Model

[0003] In order to solve the deficiencies of the above-mentioned prior art, the utility model provides a self-exhausting low-cavitation double-suction pump.

[0004] The technical solution of the utility model is as follows: A self-exhausting low-cavitation double-suction pump includes a motor and a pump body that is drivingly connected to the motor, and also includes an air ejector. The air ejector includes a controller communicatively connected to the motor, a pressure module for detecting the pressure at the liquid outlet of the pump body, and a Venturi tube located outside the pump body. The negative pressure port of the Venturi tube is connected to the exhaust port opened at the top of the pump body through an exhaust pipe, the positive pressure inlet of the Venturi tube is connected to a pressurized gas source through an inlet pipe, the positive pressure outlet of the Venturi tube is connected to the atmosphere, an intake valve is installed on the inlet pipe, and a suction valve is installed on the exhaust pipe. The intake valve and the suction valve are communicatively connected to the pressure module through the controller. By adding an air ejector outside the pump body and using the Venturi effect to remove the air in the double-suction pump chamber, compared with the traditional vacuum unit, it occupies less space and has a lower cost. Moreover, the air ejector is interlocked with the motor of the double-suction pump and the pressure at the pump liquid outlet, which can realize the self-exhausting of the double-suction pump and the self-starting after exhaust, simplify the operation process, and ensure the normal operation of the pump.

[0005] The upper threshold and the lower threshold of the pressure at the liquid outlet of the pump body are set in the controller. The controller receives the pressure value detected by the pressure module and compares it with the upper threshold and the lower threshold to control the switching states of the intake valve and the suction valve. The controller receives the pressure value at the pump liquid outlet monitored by the pressure module. When the pressure value reaches the upper threshold, the intake valve and the suction valve are closed, and the venturi tube stops exhausting. When the pressure value reaches the lower threshold, the intake valve and the suction valve are opened, and the venturi tube exhausts the air in the pump body chamber, thus avoiding the situation of air binding and no liquid delivery during the continuous operation of the pump and ensuring the continuous operation of the double-suction pump.

[0006] An installation plate is provided on one side of the venturi tube facing away from the negative pressure port. The venturi tube, the controller and the pressure switch are fixed on the pump body through the installation plate.

[0007] The intake valve is a solenoid valve, and the suction valve is a pneumatic valve. The pneumatic interface of the pneumatic valve is connected to the positive pressure inlet of the venturi tube through an air pipe. By setting the suction valve as a pneumatic valve driven by the gas at the positive pressure inlet of the venturi tube, the layout of components in the controller is reduced, and the opening and closing of the suction valve lags behind that of the intake valve, which is beneficial to the normal operation of the air ejector.

[0008] Flow guiding plates are formed on both sides of the impeller seat in the pump body chamber. The two flow guiding plates extend along the direction towards the liquid inlet of the pump body and intersect to form a flow guiding cone. The outer side of the flow guiding plate has the same curved surface structure as the inner wall of the pump body. Adding a flow guiding cone at the liquid inlet of the pump body can effectively break the vortex of the fluid sucked into the pump body, that is, reduce the generation of vortex and reduce the generation of cavitation in the pump.

[0009] A number of flow guiding grids are provided at the position of the flow guiding plate close to the impeller. The flow guiding grids are arranged on the outer side of the flow guiding plate along the circumferential direction of the impeller. Flow channels for guiding the water flow into the impeller suction port are formed between adjacent flow guiding grids. The design of the flow guiding grids evenly guides the liquid flow and improves the fluid environment at the impeller suction port, thereby improving the suction capacity of the double-suction pump.

[0010] The beneficial effects of the present utility model are as follows: By adding an air ejector outside the pump body in this solution, the venturi effect is utilized to exhaust the air in the double-suction pump chamber. Compared with the traditional vacuum unit, it has a small floor space and low cost. Moreover, the air ejector is interlocked with the motor of the double-suction pump and the pressure at the pump liquid outlet, which can realize the automatic exhaust of the double-suction pump and the self-start after exhaust, simplify the operation process, and ensure the normal operation of the pump. Description of the Drawings

[0011] Figure 1 is a schematic structural diagram of the present utility model;

[0012] Figure 2It is a schematic structural diagram of the air injector in the present utility model;

[0013] Figure 3 It is a schematic principle diagram of the present utility model;

[0014] Figure 4 It is a partial cross-sectional view of the liquid inlet of the pump body in the present utility model;

[0015] Figure 5 It is along Figure 4 A partial schematic diagram in the A direction in

[0016] Reference numerals: 1. Pump body; 101. Liquid outlet; 102. Liquid inlet; 103. Exhaust port; 104. Pressure measuring port; 105. Impeller seat; 106. Impeller suction port; 2. Air injector; 201. Controller; 202. Pressure module; 203. Venturi tube; 2031. Positive pressure inlet; 2032. Positive pressure outlet; 2033. Negative pressure port; 3. Intake valve; 4. Suction valve; 5. Mounting plate; 6. Drain elbow; 7. Exhaust pipe; 8. Intake pipe; 9. Air pipe; 10. Deflector; 11. Flow guide cone; 12. Flow guide grid. Specific implementation manners

[0017] To enable those skilled in the art to better understand the technical solutions in the present utility model, the technical solutions in the present utility model will be clearly and completely described below in conjunction with the drawings. Other embodiments obtained by those skilled in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0018] Such as Figures 1 - 3As shown in the figure, the utility model provides an autonomous exhaust type low-cavitation double-suction pump, which includes a motor and a pump body 1 that is drivingly connected to the motor. One side of the pump body 1 has a liquid inlet 102, and the other side of the pump body 1 has a liquid outlet 101. An air ejector 2 is provided outside the pump body 1. The air ejector 2 includes a controller 201 that is communicatively connected to the motor, a pressure module 202 for detecting the pressure of the liquid outlet 101 of the pump body 1, and a venturi tube 203 located outside the pump body 1. Specifically, the pressure module 202 is a pressure switch. The pressure input end of the pressure switch is connected to the pressure measuring port 104 outside the liquid outlet 101 of the pump body 1 through a pressure pipe. The pressure output end of the pressure switch is communicatively connected to the controller 201 through a signal line for inputting the pressure value to the controller 201. The negative pressure port 2033 of the venturi tube 203 is connected to the exhaust port 103 opened at the top of the pump body 1 through an exhaust pipe 7. The positive pressure inlet 2031 of the venturi tube 203 is connected to a pressurized gas source through an inlet pipe 8. The positive pressure outlet 2032 of the venturi tube 203 is connected to the atmosphere. An intake valve 3 is installed on the inlet pipe 8, and a suction valve 4 is installed on the exhaust pipe 7. The intake valve 3 and the suction valve 4 are communicatively connected to the pressure module 202 through the controller 201. The controller 201 controls the opening and closing of the intake valve 3 and the suction valve 4 based on the received pressure value. The negative pressure port 2033 of the venturi tube 203 in the air ejector 2 is connected to the exhaust port 103 at the top of the pump body 1. Utilizing the Venturi effect, a negative pressure is formed at the negative pressure port 2033 to suck the air in the double-suction pump chamber and discharge it from the positive pressure outlet 2032. Compared with the traditional vacuum unit, it occupies less space and has a lower cost. Moreover, the air ejector 2 is communicatively connected to the motor of the double-suction pump. After the air ejector 2 operates for a predetermined time, the motor can be interlocked to start, realizing the self-start of the double-suction pump. When the pressure of the liquid outlet 101 of the pump body 1 reaches the predetermined pressure, the air ejector 2 is closed through pressure interlock to complete the autonomous exhaust of the double-suction pump. The whole process simplifies the process flow and does not require manual intervention.

[0019] As Figure 2 shown, in order to make the air ejector 2 form an integrated structure and further reduce its installation space, an installation plate 5 is provided on the side of the venturi tube 203 facing away from the negative pressure port 2033. The venturi tube 203, the controller 201, and the pressure switch are fixed on the pump body 1 through the installation plate 5.

[0020] As Figure 3As shown in the figure, the upper threshold and the lower threshold of the pressure at the liquid outlet 101 of the pump body 1 are set in the controller 201. The controller 201 receives the pressure value detected by the pressure module 202 and compares it with the upper threshold and the lower threshold, and controls the switching states of the intake valve 3 and the suction valve 4. Specifically, the controller 201 receives the pressure value at the liquid outlet 101 of the pump monitored by the pressure module 202. When the pressure value reaches the upper threshold, the intake valve 3 and the suction valve 4 are closed, and the venturi tube 203 stops exhausting. When the pressure value reaches the lower threshold, the intake valve 3 and the suction valve 4 are opened, and the venturi tube 203 exhausts the air in the chamber of the pump body 1, thereby avoiding the situation of air binding and no liquid supply during the continuous operation of the pump, and ensuring the continuous operation of the double-suction pump.

[0021] As Figure 2 shown in the figure, the intake valve 3 is a solenoid valve, the suction valve 4 is a pneumatic valve, and the pneumatic interface of the pneumatic valve is connected to the positive pressure inlet 2031 of the venturi tube 203 through an air pipe 9. By setting the suction valve 4 as a pneumatic valve driven by the gas at the positive pressure inlet 2031 of the venturi tube 203, the layout of the components in the controller 201 is reduced, and the opening and closing of the suction valve 4 lags behind that of the intake valve 3, which is beneficial to the normal operation of the air ejector 2.

[0022] As Figure 4 shown in the figure, guide plates 10 are formed on both sides of the impeller seat 105 in the chamber of the pump body 1. The two guide plates 10 extend along the direction towards the liquid inlet 102 of the pump body 1 and intersect to form a guide cone 11. The outer side of the guide plate 10 has the same curved surface structure as the inner wall of the pump body 1. Adding the guide cone 11 at the liquid inlet 102 of the pump body 1 can effectively break the vortex of the fluid sucked into the pump body 1, that is, reduce the generation of vortex and reduce the generation of cavitation in the pump.

[0023] Further preferably, a number of guide grids 12 are provided at the position of the guide plate 10 close to the impeller. As Figure 5 shown in the figure, the guide grids 12 are arranged on the outer side of the guide plate 10 along the circumferential direction of the impeller. Flow channels for guiding the water flow into the impeller suction port 106 are formed between adjacent guide grids 12. Specifically, the guide grids 12 on each guide plate 10 are divided into middle guide grids located on the impeller central axis and left guide grids and right guide grids located on both sides of the impeller central axis. As Figure 5 shown in the figure, the left guide grid and the right guide grid are both arc-shaped plates bent towards the impeller central axis. Through the guide grids 12, the liquid flow is uniformly guided, the fluid environment at the impeller suction port 106 is improved, and thus the suction capacity of the double-suction pump is improved.

[0024] When implementing this technical solution, the mounting plate 5 of the air ejector 2 is fixed above the pump cover platform of the double-suction pump by bolts. As Figure 3As shown, when the valve of the double-suction pump's liquid inlet 102 is opened, the controller 201 of the air ejector 2 is turned on, the air inlet valve 3 is opened, and a compressed air source (compressed air of 0.5-1 MPa is selected) is introduced through the positive pressure inlet 2031 of the venturi tube 203, and the air intake valve 4 is pneumatically opened. Under the action of the venturi effect, the air in the double-suction pump cavity is sucked into the venturi tube 203 and discharged from the liquid discharge elbow 6 installed at one end of the positive pressure outlet 2032. After the preset time in the controller 201, the motor is interlocked and the double-suction pump is actively Start, when the pressure module 202 detects that the pressure at the pump's liquid outlet 101 reaches the upper threshold, the controller 201 interlocks to close the air inlet valve 3, and the air intake valve 4 is pneumatically closed to complete the self-exhaust of the double-suction pump. During the subsequent pump operation, the guide cone 11 and the guide grid 12 jointly improve the fluid environment in the pump suction chamber, effectively reducing the formation of cavitation. If there is air binding causing the pressure at the pump's liquid outlet 101 to drop to the lower threshold, the controller 201 interlocks to open the air ejector 2 for self-exhaust operation, thereby ensuring the normal and continuous operation of the double-suction pump.

Claims

1. An autonomous exhaust type low-cavitation double-suction pump, comprising a motor and a pump body that is drivingly connected to the motor, characterized in that, It further includes an air injector, which includes a controller communicatively connected to the motor, a pressure module for detecting the pressure at the liquid outlet of the pump body, and a Venturi tube located outside the pump body. The negative pressure port of the Venturi tube is connected to the exhaust port opened at the top of the pump body through an exhaust pipe, the positive pressure inlet of the Venturi tube is connected to a pressurized gas source through an inlet pipe, and the positive pressure outlet of the Venturi tube is connected to the atmosphere. An intake valve is installed on the inlet pipe, and a suction valve is installed on the exhaust pipe. The intake valve and the suction valve are communicatively connected to the pressure module through the controller.

2. The self-exhausting low-cavitation double-suction pump according to claim 1, wherein An upper threshold and a lower threshold of the pressure at the liquid outlet of the pump body are set in the controller. The controller receives the pressure value detected by the pressure module and compares it with the upper threshold and the lower threshold to control the on-off states of the intake valve and the suction valve.

3. The self-exhaust type low-cavitation double-suction pump according to claim 1 or 2, characterized in that, A mounting plate is provided on the side of the Venturi tube facing away from the negative pressure port. The Venturi tube, the controller, and the pressure switch are fixed to the pump body through the mounting plate.

4. The self-exhaust type low-cavitation double-suction pump according to claim 1, characterized in that, The intake valve is a solenoid valve, and the suction valve is a pneumatic valve. The pneumatic interface of the pneumatic valve is connected to the positive pressure inlet of the Venturi tube through an air pipe.

5. An autonomous exhaust type low-cavitation double-suction pump according to claim 1 or 2 or 4, characterized in that, Flow guiding plates are formed on both sides of the impeller seat in the pump body chamber. The two flow guiding plates extend along the direction towards the liquid inlet of the pump body and intersect to form a flow guiding cone. The outer sides of the flow guiding plates have the same curved surface structure as the inner wall of the pump body.

6. The self-exhaust type low-cavitation double-suction pump according to claim 5, characterized in that, A number of flow guiding grids are provided at the position of the flow guiding plate close to the impeller. The flow guiding grids are arranged on the outer side of the flow guiding plate along the circumferential direction of the impeller. Flow channels for guiding water flow into the suction port of the impeller are formed between adjacent flow guiding grids.

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