Device and method for maintaining negative pressure in water pump body after water pump stops

Abstract

A device and method for maintaining negative pressure in a water pump body after the water pump is shut down, comprising a water storage tank, solenoid valves 1 to 4, high and low level sensors, and changing the working state of each solenoid valve according to the change of high and low liquid levels, so that the solenoid valves 1 and 2 are the first group and work synchronously, and the solenoid valves 3 and 4 are the second group and work synchronously, and the two groups of solenoid valves are interlocked; a water injection port, an external exhaust port and an internal exhaust port are provided on the top of the water storage tank, and a water replenishment port is provided at the bottom of the water storage tank; the solenoid valve 4 and the solenoid valve 3 are respectively provided at the external exhaust port and the water injection port, the solenoid valve 2 is provided at the internal drain port and connected to the exhaust pipeline of the water pump body through a drain pipe, and the solenoid valve 1 is provided at the water replenishment port and connected to the water pump body through a water replenishment pipe; so that the two sub-sealed containers can cooperate with each other and operate independently. When the water pump is running, the water storage tank is filled with water with external water, so that the negative pressure in the pump body does not drop, and the water pump can be started immediately afterwards.

Description

Technical Field

[0001] The present invention belongs to a liquid water pump, and more particularly to a device and method for maintaining negative pressure in a water pump body after the water pump stops. After the water pump stops, negative pressure can be maintained in the pump body, that is, the water pump always maintains the vacuum required for starting; when the water pump is started again, there is no need to draw a vacuum, and instant starting can be achieved. Background Art

[0002] The water pump water supply and drainage system is closely related to industrial and agricultural production and the lives of the people. It is a large-scale and wide-ranging electromechanical product covering all aspects of society. The total installed capacity of water pumps in the country exceeds 10 million units. Among the water pump family, the use of liquid-surface centrifugal pumps is the largest, exceeding 90% of the total. Liquid-surface centrifugal pumps (the impeller is above the liquid surface) generally adopt the vacuum starting method. There are four forms of water pump vacuuming at present. One is to use a vacuum pump to vacuum, the second is to use a jet pump to vacuum, the third is to start the water pump and inject water into the water pump body and the water inlet pipe (the water inlet pipe needs to have a bottom valve), and the fourth is that the water inlet pipe of the water pump is higher than the water outlet pipe of the water pump (the water storage method of the pump body), and the water in the pump body is retained in the body when it is shut down. When the water pump is started again, the gas in the pump body is discharged through the rotation of the impeller to start the water pump. The above-mentioned ways of starting the water pump all have disadvantages, as follows:

[0003] 1. Vacuum pump method: This method takes a long time to start and is noisy. The vacuum device is very complicated. In addition to a number of connecting pipes and lines, it also requires an electronic control system, a detection system, a water pump motor delayed start device, etc.

[0004] 2. Jet pump method: This method takes longer to start than vacuum pump, has more failure points, and has requirements on the pressure of the water outlet pipe. Those that do not meet the conditions cannot be used.

[0005] 3. Water injection method. When using this method to start the water pump, a bottom valve must be installed on the water inlet pipe of the water pump. Its disadvantage is that the efficiency of the water pump is low and it is difficult to eliminate the failure of the bottom valve.

[0006] 4. The water storage method in the pump body. The water pump started by this method also takes a long time and cannot meet the requirements of quick start.

[0007] All of the above methods affect the realization of automation and intelligence of the water pump water supply and drainage system. Summary of the invention

[0008] The present invention aims to solve the above problems existing in the prior art and provide a device and method for maintaining negative pressure in the pump body after the pump is shut down. The invention is particularly effective in transforming long-axis pumps and self-priming pumps, and can maintain the vacuum degree in the pump body after the pump is shut down, making the pump start-up convenient, easy and simple, and keeping the vacuum degree in the pump body in a state where the pump can be started.

[0009] The technical solution of the present invention is:

[0010] A device for maintaining negative pressure in a water pump body after the water pump stops, comprising a water storage tank, solenoid valves 1 to 4, a high-level liquid sensor, and a low-level liquid sensor, wherein the working state of each solenoid valve is changed according to the change of high and low liquid levels, so that the solenoid valves 1 and 2 form a first group and work synchronously, the solenoid valves 3 and 4 form a second group and work synchronously, and the working states of the first group of solenoid valves and the second group of solenoid valves are opposite, that is, the two groups of solenoid valves are interlocked;

[0011] The top of the water tank is provided with a water filling port, an external exhaust port and an internal exhaust port, and the bottom of the water tank is provided with a water replenishment port; the solenoid valve four is arranged at the external exhaust port, and is used to discharge the gas in the water tank, and the solenoid valve three is arranged at the water filling port, and is used to control the water injection into the water tank; the solenoid valve two is arranged at the internal drain port and is connected to the exhaust pipeline of the water pump body through the drain pipe, and is used to discharge the gas in the water pump body to the top of the water tank; the solenoid valve one is arranged at the water replenishment port and is connected to the water pump body through the water replenishment pipe, and is used to replenish water into the water pump body;

[0012] When solenoid valve 1 and solenoid valve 2 are opened, the water pump body and the water tank form a unified closed container through the water supply pipe and the exhaust pipe; when solenoid valve 1 and solenoid valve 2 are closed, the water pump body and the water tank become two independent sub-closed containers, so that the two sub-closed containers can cooperate with each other and operate independently.

[0013] Furthermore, the inner bottom surface of the water storage tank is higher than the inner top surface of the water pump body.

[0014] Furthermore, it also includes a controller, the signal output ends of the high liquid level sensor and the low liquid level sensor are connected to the controller, and the controller control signal output end is connected to the electromagnetic valve 1 to the electromagnetic valve 4.

[0015] Furthermore, the controller adopts PLC.

[0016] The method for maintaining negative pressure in the pump body of a water pump after the water pump is stopped by using the above-mentioned device for maintaining negative pressure in the pump body of a water pump after the water pump is stopped, and the steps are as follows:

[0017] 1. After the water pump stops, the solenoid valve 1 arranged at the water replenishment port and the solenoid valve 2 arranged at the internal exhaust port are opened. At this time, the water pump body and the water storage tank form a large closed container. After the vacuum degree in the water pump body decreases, the water in the water storage tank begins to be replenished into the water pump body through the water replenishment pipe. At the same time, the gas in the water pump body is discharged to the top of the water storage tank through the drain pipe to maintain the vacuum degree required for startup;

[0018] 2. When the water level in the water tank drops to the set low water level, the low liquid level sensor receives a signal to close the solenoid valve 1 at the water filling port and the solenoid valve 2 at the internal exhaust port. At this time, the pump body and the water tank become two closed containers. At the same time, the solenoid valve 3 at the water filling port and the solenoid valve 4 at the external exhaust port are opened to fill water into the water tank. After the water pump stops, the device for maintaining negative pressure in the pump body starts to operate independently.

[0019] 3. When the water level in the water storage tank rises to the set high water level, the low liquid level sensor receives a signal to close the solenoid valve 3 arranged at the water filling port and the solenoid valve 4 arranged at the external exhaust port; at the same time, the solenoid valve 1 arranged at the water replenishment port and the solenoid valve 2 arranged at the internal exhaust port are opened, so that there is always water in the pump body and the vacuum required for startup is always maintained.

[0020] Furthermore, the water pump is started by using a vacuum device when starting for the first time before step 1.

[0021] Furthermore, the inner bottom surface of the water storage tank is higher than the inner top surface of the water pump body.

[0022] Furthermore, the output switch signals of the high-level liquid level sensor and the low-level liquid level sensor are transmitted to the controller, and the working states of the solenoid valves 1 to 4 are controlled by the controller.

[0023] Furthermore, the controller adopts PLC.

[0024] The present invention adds a set of devices to the water pump to maintain negative pressure in the pump body after the water pump stops. The device is small in size and simplifies the vacuum pumping device with complex structure, frequent failures and many pipelines. It is easy to use, easy to install and has a low failure rate. It can also reduce the purchase cost of equipment, reduce maintenance costs, reduce daily maintenance, improve water pump efficiency and extend service life. When the water pump is running, the water storage tank will be filled with water with external water, which can keep the negative pressure in the pump body from decreasing. It only needs to start the water pump with the vacuum pumping device for the first time (the device that maintains negative pressure in the pump body after the water pump stops can also directly start the water pump), and then the water pump can be started immediately. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the present invention;

[0026] Figure 2 It is the control principle diagram of the present invention.

[0027] In the figure: 1. water storage tank, 2. low liquid level sensor, 3. high liquid level sensor, 4. water filling pipe, 5. exhaust pipe, 6. water pump body, 7. water supply pipe, 8. solenoid valve 1, 9. solenoid valve 2, 10. solenoid valve 4, 11. solenoid valve 3, 101. water supply port, 102. internal exhaust port, 103. water filling port, 104. external exhaust port. DETAILED DESCRIPTION

[0028] As shown in the figure, the device for maintaining negative pressure in the pump body after the water pump is stopped includes a water storage tank 1, a solenoid valve 1 8, a solenoid valve 2 9, a solenoid valve 3 11, a solenoid valve 4 10, a low-level liquid sensor 2 and a high-level liquid sensor 3. The low-level liquid sensor 2 and the high-level liquid sensor 3 are respectively installed at the bottom and the top of the water storage tank 1 and are connected to the controller. The output end of the controller is connected to each solenoid valve to control the working state of each solenoid valve according to the change of the liquid level. The controller adopts PLC. In this embodiment, the device is self-contained and adopts Siemens S7-200 PLC (can also be configured by the user), so that the solenoid valve 1 8 and the solenoid valve 2 9 are a group (the first group) and work synchronously, the solenoid valve 3 11 and the solenoid valve 4 10 are another group (the second group) and work synchronously, and the two groups of solenoid valves are interlocked; a water injection port 103, an external exhaust port 104 and an internal exhaust port 102 are provided on the top of the water storage tank 1, a water replenishment port 101 is provided at the bottom of the water storage tank 1, the solenoid valve 3 11 is arranged at the water injection port 103 and the water injection port 103 is connected to the water injection pipe 4, and the water injection pipe 4 and the other end are connected to an external water source for controlling water injection into the water storage tank 1. The solenoid valve 4 10 is arranged at the external drain port 104 for exhausting the air in the water storage tank. The solenoid valve 1 8 is arranged at the water replenishment port 101, the water replenishment port 101 is connected to the water replenishment pipe 7, the other end of the water replenishment pipe 7 is connected to the inner cavity of the water pump body 6, and is used to replenish water into the water pump body 6. The solenoid valve 2 9 is arranged at the internal exhaust port 102, the internal exhaust port 102 is connected to the exhaust pipe 5, the other end of the exhaust pipe 5 is connected to the exhaust pipeline of the water pump body 6. When the solenoid valve 1 8 and the solenoid valve 2 9 are opened, the water pump body 6 and the water storage tank 1 form a unified closed container through the water replenishment pipe 7 and the exhaust pipe 5; when the solenoid valve 1 8 and the solenoid valve 2 9 are closed, the water pump body 6 and the water storage tank 1 become two independent sub-closed containers respectively, so that the two sub-closed containers can cooperate with each other and operate independently.

[0029] The inner bottom surface of the water storage tank 1 is higher than the inner top surface of the water pump body 6 .

[0030] The method for maintaining negative pressure in the pump body of a water pump after the water pump is stopped by using the above-mentioned device for maintaining negative pressure in the pump body of a water pump after the water pump is stopped, and the steps are as follows:

[0031] 1. After the water pump is stopped, the solenoid valve 1 8 arranged at the water replenishment port 101 and the solenoid valve 2 9 arranged at the internal exhaust port 102 are opened. At this time, the water pump body 6 and the water storage tank 1 form a large closed container. After the vacuum degree in the water pump body 6 decreases, the water in the water storage tank 1 begins to be replenished into the water pump body 6. At the same time, the gas in the water pump body 6 is discharged to the top of the water storage tank 1 through the drain pipe 5 to maintain the vacuum degree required when the water pump is started;

[0032] 2. When the water level in the water storage tank 1 drops to the set low water level, the low liquid level sensor 2 receives a signal, and the solenoid valve 1 8 arranged at the water replenishment port 101 and the solenoid valve 2 9 arranged on the exhaust port 102 are closed through the controller. At this time, the water pump body 6 and the water storage tank 1 become two closed containers. At the same time, the solenoid valve 3 11 arranged at the water injection port 103 and the solenoid valve 4 10 arranged at the external exhaust port 104 are opened to inject water into the water storage tank 1. After the water pump is stopped, the device for maintaining the negative pressure in the water pump body starts to operate independently;

[0033] 3. When the water level in the water storage tank 1 rises to the set high water level, the high liquid level sensor 3 receives a signal, and the solenoid valve 3 11 arranged at the water filling port 103 and the solenoid valve 4 10 arranged at the external exhaust port 104 are closed through the controller; at the same time, the solenoid valve 1 8 arranged at the water replenishment port 101 and the solenoid valve 2 9 arranged at the internal exhaust port 102 are opened, so that there is always water in the water pump body 6, and the vacuum degree required when the water pump is started is always maintained.

[0034] Furthermore, the water pump is started by using a vacuum device when starting for the first time before step 1.

[0035] The process of water storage tank 1 replenishing water into water pump body 6 is a process of energy conversion. The bottom surface of water storage tank 1 is higher than the top surface of water pump body 6, the potential energy of liquid in water storage tank is converted into potential energy in pump body, the liquid in pump body is rising continuously, the gas in pump body is discharged continuously, so the vacuum degree in pump body is maintained.

[0036] The output switch signals of the high-level liquid sensor 3 and the low-level liquid sensor 1 are transmitted to the controller, and the working states of the solenoid valves 1 to 4 are controlled by the controller, which adopts PLC.

[0037] After the water pump stops, the vacuum degree in the water pump body is P. As it is difficult to completely seal the water pump and its connections, the negative pressure in the water pump body tends to decrease over time. When the liquid level drops to the lowest level, the vacuum degree decreases by ΔP. When the water storage tank starts to fill the pump body with water, the water level in the water pump body rises, and the vacuum degree increases by another ΔP, returning to the vacuum degree P required to start the water pump.

[0038] After one or several reciprocating cycles, the vacuum degree in the pump body returns to the vacuum degree required when the pump is started.

[0039] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for maintaining negative pressure in a water pump body after the water pump stops, characterized in that: It includes a water storage tank, solenoid valve 1, solenoid valve 2, solenoid valve 3, solenoid valve 4, a high liquid level sensor, a low liquid level sensor and a controller. The working state of each solenoid valve is changed according to the change of high and low liquid levels, so that the solenoid valve 1 and the solenoid valve 2 are the first group of solenoid valves and work synchronously, the solenoid valve 3 and the solenoid valve 4 are the second group of solenoid valves and work synchronously, and the working state of the first group of solenoid valves is opposite to that of the second group of solenoid valves, that is, the two groups of solenoid valves are interlocked; the signal output ends of the high liquid level sensor and the low liquid level sensor are connected to the controller, and the control signal output end of the controller is connected to the solenoid valve 1, the solenoid valve 2, the solenoid valve 3 and the solenoid valve 4; The top of the water tank is provided with a water filling port, an external exhaust port and an internal exhaust port, and the bottom of the water tank is provided with a water replenishment port; the solenoid valve four is arranged at the external exhaust port for discharging the gas in the water tank, and the solenoid valve three is arranged at the water filling port for controlling the injection of water into the water tank; the solenoid valve two is arranged at the internal exhaust port and connected to the exhaust pipeline of the water pump body through the exhaust pipe, so as to discharge the gas in the water pump body to the top of the water tank; the solenoid valve one is arranged at the water replenishment port and connected to the water pump body through the water replenishment pipe, so as to replenish water into the water pump body; the inner bottom surface of the water tank is higher than the top surface of the water pump body; When solenoid valve 1 and solenoid valve 2 are opened, the water pump body and the water tank form a unified closed container through the water supply pipe and the exhaust pipe; when solenoid valve 1 and solenoid valve 2 are closed, the water pump body and the water tank become two independent sub-closed containers, so that the two sub-closed containers can cooperate with each other and operate independently.

2. The device for maintaining negative pressure in a water pump body after the water pump is shut down according to claim 1, characterized in that: The controller adopts PLC.

3. A method for maintaining negative pressure in a water pump body after the water pump is stopped by using the device for maintaining negative pressure in a water pump body after the water pump is stopped as claimed in claim 1, characterized in that: as follows: 1) After the water pump stops, the solenoid valve 1 arranged at the water replenishment port and the solenoid valve 2 arranged at the internal exhaust port are opened. At this time, the water pump body and the water storage tank form a large closed container. After the vacuum degree in the water pump body decreases, the water in the water storage tank begins to be replenished into the water pump body through the water replenishment pipe. At the same time, the gas in the water pump body is discharged to the top of the water storage tank through the exhaust pipe to maintain the vacuum degree required for startup; 2) When the water level in the water storage tank drops to the set low water level, the low liquid level sensor receives a signal to close the solenoid valve 1 set at the water replenishment port and the solenoid valve 2 set at the internal exhaust port. At this time, the pump body and the water storage tank become two closed containers. At the same time, the solenoid valve 3 set at the water injection port and the solenoid valve 4 set at the external exhaust port are opened to inject water into the water storage tank. After the water pump stops, the device that maintains the negative pressure in the pump body starts to operate independently; 3) When the water level in the water storage tank rises to the set high water level, the low liquid level sensor receives a signal to close the solenoid valve 3 arranged at the water filling port and the solenoid valve 4 arranged at the external exhaust port; at the same time, the solenoid valve 1 arranged at the water replenishment port and the solenoid valve 2 arranged at the internal exhaust port are opened, so that there is always water in the pump body and the vacuum required for startup is always maintained.

4. The method for maintaining negative pressure in a water pump body after the water pump is shut down according to claim 3, characterized in that: Use the vacuum device to start the pump for the first time before step 1).

5. The method for maintaining negative pressure in a water pump body after the water pump is shut down according to claim 3, characterized in that: The controller adopts PLC.

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