Self-priming device for a pump and pump group

Abstract

The utility model relates to a pump field, concretely relates to a pump is with self priming device and pump group. The self priming device includes vacuum pump, vacuum jar and at least one liquid level sensor, the vacuum jar is connected with the liquid inlet side of centrifugal pump, and the inside of vacuum jar is communicated with the pump cavity of centrifugal pump, the vacuum jar is connected with vacuum pump through vacuum pipeline, and vacuum pump can form the negative pressure in vacuum jar, and then through the negative pressure and inhale the external medium into the pump cavity of centrifugal pump, the liquid level sensor is arranged in the vacuum jar, and the setting height of liquid level sensor is not lower than the highest place of the pump cavity of centrifugal pump, the liquid level sensor is used for monitoring the liquid level in the vacuum jar, to adapt the control assembly of subsequent control vacuum pump start -stop. The self priming device for pump of the utility model is separately formed into a module, is quickly installed combination through the vacuum jar and the liquid inlet of existing different models centrifugal pump, does not need to make substantial modification to centrifugal pump, and the adaptability is wide.

Description

Technical Field

[0001] This utility model relates to the field of pumps, specifically to a self-priming device and pump set for pumps. Background Technology

[0002] Traditional pumps require water to be added before they can be started, making the startup process laborious. Furthermore, special media (such as volatile liquids, acids, or alkalis) cannot be manually injected. In addition, traditional self-priming pumps currently used in chemical and petroleum industries suffer from low self-priming efficiency, significant dry-running wear, energy waste, repeated clutch engagement and disengagement, and frequent vacuum pump start-stop cycles, all of which affect equipment lifespan and operational stability. Utility Model Content

[0003] (a) Technical problems to be solved

[0004] Technical Problem to be Solved: In view of the above-mentioned shortcomings and deficiencies of the existing technology, this utility model provides a self-priming device and pump set for pumps, which solves the problems of existing pumps requiring manual injection of liquid medium before operation, low self-priming efficiency, energy waste, repeated suction and disengagement of the clutch device, and frequent start and stop of vacuum pumps. At the same time, it improves the versatility of the self-priming device and adapts it to existing centrifugal pumps.

[0005] (II) Technical Solution

[0006] In a first aspect, this utility model provides a self-priming device for a pump, comprising: a vacuum pump, a vacuum tank, and at least one liquid level sensor; the vacuum tank is connected to the inlet side of a centrifugal pump, and the interior of the vacuum tank is in communication with the pump chamber of the centrifugal pump; the vacuum tank and the vacuum pump are connected through a vacuum pipe, and the vacuum pump can create a negative pressure inside the vacuum tank, thereby drawing external media into the pump chamber of the centrifugal pump through the negative pressure; the liquid level sensor is disposed inside the vacuum tank, and the placement height of the liquid level sensor is not lower than the highest point of the pump chamber of the centrifugal pump; the liquid level sensor is used to monitor the liquid level inside the vacuum tank to adapt to the subsequent control components for controlling the start and stop of the vacuum pump.

[0007] The self-priming device for pumps is used in conjunction with centrifugal pumps to achieve self-priming function. It is suitable for scenarios in chemical, petroleum, mining, flood control and other fields that require rapid self-priming and avoid manual injection.

[0008] Preferably, the vacuum tank includes a tank body and a horizontal mounting pipe, the tank body is connected to the middle section of the horizontal mounting pipe, one end of the horizontal mounting pipe is used to connect to the inlet of the centrifugal pump, and the other end is used to connect to the suction pipe.

[0009] Preferably, both ends of the transverse mounting pipe are provided with flange faces. The flange structure of the transverse mounting pipe allows for quick installation and combination with various common centrifugal pump inlets, improving the versatility of the self-priming device.

[0010] Preferably, the vacuum tank is equipped with a first liquid level sensor and a second liquid level sensor. The first liquid level sensor is located at the bottom of the vacuum tank, and the height of the first liquid level sensor is not lower than the highest point of the pump chamber of the centrifugal pump. The second liquid level sensor is installed at a higher height than the first liquid level sensor.

[0011] Preferably, the second liquid level sensor is located at the top of the vacuum tank, and there is a gap between the second liquid level sensor and the top of the vacuum tank. This gap is 1 / 5 to 1 / 10 of the height of the inner cavity of the vacuum tank, which helps to store a certain negative pressure and maintain a certain distance in the vacuum tank, thereby reducing the frequent start-stop of the vacuum pump and controlling oscillation.

[0012] Preferably, the vacuum pipe connecting the vacuum tank to the vacuum pump is equipped with an air check valve and a gas-liquid separator to prevent liquid from entering the vacuum pump during the vacuum tank's liquid intake process and to avoid cavitation damage to the vacuum pump.

[0013] Secondly, this utility model provides a pump set, comprising: a drive device, a centrifugal pump, and a self-priming device for the pump as described in any of the above embodiments; the drive device is driven to the input shaft of the centrifugal pump to drive the centrifugal pump to rotate; the drive device and the vacuum pump are connected by a clutch device, the clutch device being used to switch the power transmission state between the drive device and the vacuum pump (engaging to transmit power, disengaging to cut off power); the liquid level sensor is electrically connected to the main control circuit, the main control circuit is connected to the control circuit of the clutch device, and the main control circuit outputs a control signal to the control circuit of the clutch device to switch the clutch device between engagement and disengagement.

[0014] Preferably, the drive device is a diesel engine or an electric motor.

[0015] Preferably, the outlet of the centrifugal pump is connected to an outlet short pipe, the side wall of the outlet short pipe is provided with a side pipe interface, a ball valve is installed at the side pipe interface, and the side pipe interface is connected to the shaft seal assembly of the centrifugal pump through a return pipe.

[0016] Preferably, a check valve and a solenoid butterfly valve are also installed at the rear end of the outlet short pipe, and the end of the outlet short pipe is connected to a drain pipe. The check valve can prevent the medium from flowing back into the pump chamber of the centrifugal pump and forming water hammer. The solenoid butterfly valve is used to close when the pump is stopped to prevent the medium from flowing back or siphoning in the main pipeline and to reduce the load impact when the centrifugal pump is restarted.

[0017] Preferably, the pump set further includes a base; the drive unit, centrifugal pump, vacuum pump and vacuum tank are mounted on the base; if the drive unit is a diesel engine, the base also integrates a fuel tank and fuel pipeline, the fuel tank supplies fuel to the diesel engine through the fuel pipeline, avoiding unstable fuel supply due to excessively long fuel pipeline; if the drive unit is an electric motor, the base also integrates a battery, a small generator or UPS uninterruptible power supply, to avoid mechanical failure and circuit damage caused by sudden power outages.

[0018] Preferably, the base further comprises at least one of the following functional components:

[0019] Functional component one: The base is equipped with a skid for dragging and moving the entire pump unit;

[0020] Functional component two: A buoyancy body is provided under the base, allowing the entire pump unit to float and operate on mud or water.

[0021] Functional component three: A hanger is provided on one side of the base, and a sling is provided below the hanger for suspending the suction tube; the suction tube is connected to the vacuum tank through the flange face of the end of the horizontally installed tube. The hanger and sling can distribute the weight of the suction tube and reduce the bearing capacity of the flange bolts.

[0022] According to a preferred embodiment of the present invention, the transmission connection structure between the drive device and the vacuum pump is one of the following two:

[0023] Structure 1: The output end of the drive device is equipped with a first pulley, and the input shaft of the vacuum pump is equipped with a clutch device, which includes a second pulley; the first pulley and the second pulley are connected by a belt. Structure 2: The drive device is connected to the input shaft of a centrifugal pump, and a first pulley is installed on the pump shaft of the centrifugal pump; the input shaft of the vacuum pump is equipped with a clutch device, which includes a second pulley; the first pulley and the second pulley are connected by a belt.

[0024] According to a preferred embodiment of the present invention, in order to avoid liquid splashing causing erroneous sensing of the liquid level sensor, multiple liquid level sensors can be distributed at the height of the first liquid level sensor and the second liquid level sensor to prevent single-point sensing failure from causing control failure.

[0025] (III) Beneficial Effects

[0026] 1. The self-priming device for pumps of this utility model is a separate module. The vacuum tank of the self-priming device can be quickly installed and combined with the inlet of existing centrifugal pumps of different models without requiring major modifications to the centrifugal pumps. It has wide adaptability and reduces application costs. The horizontal mounting pipe and flange structure at both ends of the vacuum tank do not require structural modifications to existing centrifugal pumps. The self-priming device for pumps can be assembled with the centrifugal pump simply by connecting it to the inlet side of the centrifugal pump.

[0027] 2. Automated self-priming, no manual intervention required: By cooperating with a vacuum pump and vacuum tank, the centrifugal pump is switched from traditional exhaust to air intake before operation, eliminating the need for manual liquid injection; the liquid level sensor and the main control circuit work together to control the clutch device, enabling the vacuum pump to start and stop on demand, avoiding dry running and wear, and solving the problem of traditional pumps requiring pre-filling with water.

[0028] 3. Optimized control and extended equipment lifespan: The dual-level sensor design (first and second level sensors), combined with the spacing between the second level sensor and the top of the vacuum tank, allows for precise monitoring of the liquid level and adjustment of the vacuum tank's negative pressure. This reduces repeated engagement and disengagement of the clutch and frequent start-stop of the vacuum pump, extending equipment lifespan and saving energy. Triggering the second level sensor stops the vacuum pump, preventing liquid from entering and damaging it.

[0029] 4. Adaptable to various drive and working conditions: The drive unit can be either a diesel engine or an electric motor to meet different power requirements; the base is combined with skid-mounted, buoyancy body and other components, so that the pump set can adapt to complex working conditions such as land towing and water floating (such as mud pools and flood rescue), and can be deployed flexibly.

[0030] 5. Comprehensive protection components: The air check valve and gas-liquid separator on the vacuum pipeline can prevent liquid from entering the vacuum pump; the check valve, solenoid butterfly valve and reflux pipe structure of the liquid outlet short pipe can not only prevent the medium from backflowing and damaging the centrifugal pump, but also use the medium to cool the shaft seal assembly and maintain the shaft seal life.

[0031] In summary, this invention can significantly improve self-priming efficiency, reduce maintenance costs, and solve the problems of energy waste and operating condition limitations, making it suitable for high-requirement fields such as petrochemicals, mining, and flood control. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the pump unit of this utility model. Figure 1 ;

[0033] Figure 2 This is a schematic diagram of the pump unit of this utility model. Figure 2 ;

[0034] Figure 3 This is a schematic diagram of the pump unit of this utility model. Figure 3 .

[0035] Explanation of symbols in the diagram: 1-Diesel engine (or electric motor), 2-Centrifugal pump, 22-Outlet short pipe, 23-Check valve, 221-Side interface, 222-Return pipe, 24-Solenoid butterfly valve, 5-Vacuum tank, 51-Horizontal mounting pipe, 52-Tank body, 6-Vacuum pump, 7-Vacuum pipeline, 72-Air check valve, 71-Gas-liquid separator, 100-Base, 101-Skirt mount, 102-Hanger, 1021-Sling, 1051-Reel, 9-Suction pipe. Detailed Implementation

[0036] To better explain and facilitate understanding of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1 As shown, this utility model provides a self-priming device and pump assembly for a pump, which includes a base 100, a diesel engine 1 mounted on the base 100, a centrifugal pump 2, a vacuum pump 6, and a vacuum tank 5. The centrifugal pump 2 includes an inlet and an outlet, with the inlet side connected to the vacuum tank 5. The top of the vacuum tank 5 is connected to the vacuum pump 6 via a vacuum pipe 7. The vacuum tank 5 includes a tank body 52 and a transverse mounting pipe 51. One end of the transverse mounting pipe 51 has a flange face, which connects to the inlet of the centrifugal pump 2. The other end of the transverse mounting pipe 51 also has a flange face, which connects to an inlet pipe 9. The upper side of the middle section of the transverse mounting pipe 51 is connected to the bottom of the tank body 52 (e.g., ...). Figure 2 (As shown). When the vacuum pump 6 is working, it evacuates the tank 52 of the vacuum tank 5 through the vacuum pipe 7, creating a negative pressure inside both the tank 52 and the transverse mounting pipe 51. One end of the transverse mounting pipe 51 is connected to the inlet of the centrifugal pump 2. The negative pressure causes the external medium to be continuously drawn into the transverse mounting pipe 51 through the inlet pipe 9, and then into the centrifugal pump 2 from the other end of the transverse mounting pipe 51, thus completing the self-priming liquid intake of the centrifugal pump 2.

[0038] In this system, the power output of diesel engine 1 is connected to centrifugal pump 2 to drive its operation. The power output from diesel engine 1 is connected to the pump shaft of vacuum pump 6 via a clutch device, which can be implemented in two ways: Method 1: The power output of diesel engine 1 is equipped with a first pulley, and a clutch device is installed on the pump shaft of vacuum pump 6. This clutch device includes a second pulley, and the first and second pulleys are connected by a belt ring. Method 2: The power output of diesel engine 1 is connected to the pump shaft of centrifugal pump 2, and the pump shaft of centrifugal pump 2 also has a first pulley. A clutch device is installed on the pump shaft of vacuum pump 6, and this clutch device includes a second pulley, and the first and second pulleys are connected by a belt ring. Both methods allow vacuum pump 6 to be driven by diesel engine 1 and begin vacuuming, or to immediately disconnect the power from diesel engine 1 and stop vacuuming.

[0039] At least one liquid level sensor is installed inside the vacuum tank 5, with its height not lower than the highest point of the centrifugal pump 2. This liquid level sensor is connected to the main control circuit, which in turn is connected to the control circuit (or drive circuit) of the clutch device. When the liquid level in the vacuum tank 5 reaches the liquid level sensor, it means that the centrifugal pump 2 is completely filled with water. The main control circuit, where the liquid level sensor is located, outputs a control signal to the control circuit of the clutch device, causing the clutch device to disengage. At this time, the power of the drive device 1 is no longer output to the vacuum pump 6, but only to the centrifugal pump 2, thus saving energy. Conversely, when the liquid level does not reach the liquid level sensor, it means that the centrifugal pump 2 has not reached the state of complete water intake. At this time, the main control circuit outputs another control signal to the control circuit of the clutch device, keeping the clutch device engaged. Thus, the power of the drive device 1 continues to be supplied to the vacuum pump 6, which maintains the negative pressure inside the tank 52 and the horizontal mounting pipe 51, allowing the liquid to continue to fill the centrifugal pump 2.

[0040] In another preferred embodiment, a first liquid level sensor is positioned lower than the first liquid level sensor and a second liquid level sensor is positioned higher (located inside the vacuum tank 5 and therefore not shown in the figure). The first liquid level sensor is located near the bottom of the vacuum tank, and the second liquid level sensor is positioned higher than the first liquid level sensor, but the height of the first liquid level sensor is not lower than the highest point of the pump chamber of the centrifugal pump 2. At this time, the main control circuit of the pump device is electrically connected to the first and second liquid level sensors. When the centrifugal pump 2 starts, if the first liquid level sensor does not detect the liquid level, the main control circuit controls the clutch to immediately engage, causing the vacuum pump 6 to be driven by the diesel engine 1 and begin vacuuming. When the liquid level in the vacuum tank 5 exceeds the first liquid level sensor, the clutch remains engaged. When the second liquid level sensor has detected the liquid level, the main control circuit controls the clutch to immediately disengage, immediately disconnecting the power from the diesel engine 1 and stopping the vacuuming operation. Therefore, the first liquid level sensor mainly triggers the clutch to engage, while the second liquid level sensor mainly triggers the clutch to disengage, ensuring that the centrifugal pump 2 is under high negative pressure and full of water, and providing a certain margin to prevent the clutch from repeatedly engaging and disengaging. Of course, if the liquid level in the vacuum tank 5 is between the first and second liquid level sensors during startup, the clutch can also be triggered to engage.

[0041] At the initial startup of the pump unit, since the liquid level in the vacuum tank 5 has not yet reached the position of the first liquid level sensor, the circuit controls the clutch to be engaged. The vacuum pump 6 and the centrifugal pump 2 are simultaneously driven by the diesel engine 1, creating a negative pressure inside the centrifugal pump 2 chamber, which rapidly self-primes and injects liquid. The centrifugal pump 2 begins normal operation and liquid pumping. During this stage, the vacuum pump 6 remains operational, maintaining a full negative pressure and high delivery efficiency. As the vacuum pump 6 continues to pump, a large amount of liquid enters the vacuum tank 5 and gradually rises to or exceeds the set height of the second liquid level sensor. At this point, the circuit controls the clutch to disengage, and the vacuum pump 6 stops receiving power from the diesel engine 1 and stops pumping. The driving energy of the drive device 1 is then mainly provided to the centrifugal pump 2, saving energy. In other words, during the pump startup process, the first liquid level sensor primarily triggers the vacuum pump 6 to start vacuuming (the pipeline connected to the outlet of the centrifugal pump 2 should remain closed) and achieves self-priming, accelerating the startup process. During the normal operation of the pumping device (the pipeline connected to the outlet of the centrifugal pump 2 is open), the second liquid level sensor then triggers the vacuum pump 6 to stop or start. When the liquid level in the vacuum tank 5 exceeds the second liquid level sensor, the main control circuit disengages the clutch, at which point the vacuum pump 6 stops working to save energy, allowing the driving energy of the diesel engine 1 to be mainly used for the operation of the centrifugal pump 2. When the liquid level in the vacuum tank 5 is lower than the second liquid level sensor (indicating that there may still be air in the vacuum tank 5), the main control circuit immediately engages the clutch, further reducing the pressure inside the centrifugal pump 2, allowing more liquid to enter the centrifugal pump 2, ensuring that the pump is always operating at high delivery efficiency. If the second liquid level sensor fails, liquid may enter the vacuum pump and damage the vacuum pump 6. Therefore, the water level in the vacuum tank 5 should be controlled to not exceed the second liquid level sensor or reach the top of the vacuum tank 5.

[0042] Preferably, there is still a certain amount of space above the second liquid level sensor inside the vacuum tank 5, that is, there is a gap between the second liquid level sensor and the top of the vacuum tank 5 (the gap is 1 / 5 to 1 / 10 of the height of the inner cavity of the vacuum tank), which helps to store a certain negative pressure inside the vacuum tank 5, reduce the frequent start and stop of the vacuum pump and control oscillation, extend the equipment life and save energy. This extra space can prevent the vacuum tank 5 from being filled with water, causing water to enter the vacuum pump 6.

[0043] In summary, the first liquid level sensor is the condition for "starting the vacuum pump" at the beginning of the pump set startup, and the second liquid level sensor is the condition for "stopping the vacuum pump" or "starting the vacuum pump" during the operation of the pump set. The purpose of setting two liquid level sensors, one low and one high, in the vacuum tank 5 is to: (1) achieve automatic and reliable self-priming startup. No manual pump priming or pre-priming is required, which significantly improves the convenience of operation and the degree of automation. (2) avoid "accidental stop" and "suction interruption", ensuring the complete completion of the self-priming process. Prevent the vacuum pump from stopping too early, ensure the complete completion of the self-priming process, and improve the reliability of system startup. (3) prevent "frequent start and stop", improve system stability, significantly reduce the start and stop frequency of the vacuum pump, extend equipment life, and reduce energy consumption and noise. (4) Once the liquid level reaches the second liquid level sensor, it indicates that self-priming has been completed, and the centrifugal pump can continue to deliver by its own capacity. At this time, the vacuum pump power is immediately cut off (clutch device is disengaged) to stop it from working. Technical effect: avoid the vacuum pump from running continuously in the normal delivery stage, save diesel engine power, and improve the overall energy efficiency. (5) Dual protection enhances system safety and fault tolerance. The first liquid level sensor ensures that the system will start when suction is required, while the second liquid level sensor ensures that the system will stop when the liquid level is too high. The first liquid level sensor is mainly used for auxiliary control during the startup process, while the second liquid level sensor is responsible for monitoring the normal operating status of the system and ensuring that the vacuum pump is shut down in time when no additional vacuuming is required, thereby optimizing energy efficiency and protecting the system from overload or overflow.

[0044] Combination Figure 1 or Figure 3 As shown, the outlet of centrifugal pump 2 is connected to an outlet short pipe 22, and a pressure gauge is installed at the outlet short pipe 22 to detect the outlet pressure of centrifugal pump 2. A side pipe interface 221 is provided on the side wall of the outlet short pipe 22, and a ball valve is installed at the side pipe interface 221. The main function of the side pipe interface 221 is to connect to the shaft seal assembly of centrifugal pump 2 through the return pipe 222, using the high-pressure water output from centrifugal pump 2 to flush, cool, and de-temperature the shaft seal assembly. The ball valve is only opened when the medium is clean water to avoid contamination and wear of the shaft seal assembly due to poor water quality. When the medium is clean water, the side pipe interface 221 is connected to a return pipe 222, the ball valve is opened, and the high-pressure water inside centrifugal pump 2 flows through the return pipe 222 to perform high-pressure flushing and cooling of the shaft seal assembly of centrifugal pump 2, without the need for external priming water.

[0045] A check valve 23 is also installed at the rear end of the outlet short pipe 22. The check valve 23 prevents water from backflowing into the pump chamber of the centrifugal pump 2 due to siphoning, thus preventing water hammer and damage to the components of the centrifugal pump 2. A solenoid butterfly valve 24 is also installed at the rear end of the outlet short pipe 22. The rear end of the solenoid butterfly valve is connected to the drain pipe via a flange. During shutdown or initial startup, the solenoid butterfly valve 24 is closed (or the check valve 23 is manually closed) to prevent liquid from flowing back into the pump chamber of the centrifugal pump due to siphoning, thus reducing the load impact when the centrifugal pump 2 restarts.

[0046] like Figure 1 As shown, the vacuum pipeline 7 connecting the vacuum tank 5 and the vacuum pump 6 is equipped with an air check valve 72 and a gas-liquid separator 71 to prevent liquid entering the vacuum tank 5 from entering the vacuum pump 6, thus blocking liquid from entering the vacuum pump 6 and avoiding cavitation damage to the vacuum pump 6. In some embodiments, the air check valve 72 and the gas-liquid separator 71 can also be an integrated device of cyclone separator and mechanical check valve to reduce pipeline nodes and improve reliability.

[0047] like Figure 1 As shown, the base 100 also integrates an oil tank and oil supply pipeline. The oil tank supplies oil to the drive unit through the oil supply pipeline, avoiding unstable oil supply caused by excessively long oil supply pipelines. The base 100 can also be equipped with a skid 101 for dragging and moving the entire pump unit. The base 100 is equipped with a hanger 102, and a sling 1021 is provided below the hanger 102, which is mainly used for slinging the suction pipe 9. The other end of the sling 1021 can be wound on a reel, which is fixed to the equipment frame above the base. The reel can be released to extend the sling length as needed. The outer end of the inlet short pipe 21 is provided with a flange face, through which the suction pipe 9 is connected to the inlet short pipe 21. The structure of the hanger 102 and the sling 1021 can sling the suction pipe 9, preventing the suction pipe 9 from being too heavy, which would cause installation inconvenience or excessive load on the flange bolts on the flange face connecting the suction pipe 9 and the inlet short pipe 21.

[0048] In some embodiments, a buoyancy body may be provided below the base 100, allowing the entire pump unit to float on mud or water, adapting to complex environments (such as mud pits and flood relief) and reducing deployment time. The pump unit of this invention has high pumping efficiency and stable performance, making it particularly suitable for applications such as mine drainage.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions, or combinations of technical features in the above embodiments that do not conflict with each other, can be made in accordance with the manner described in the embodiments. These modifications, substitutions or combinations do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A self-priming device for a pump, characterized in that, include: The system includes a vacuum pump, a vacuum tank, and at least one liquid level sensor. The vacuum tank is connected to the inlet side of the centrifugal pump, and the interior of the vacuum tank is in communication with the pump chamber of the centrifugal pump. The vacuum tank and the vacuum pump are connected via a vacuum pipe, and the vacuum pump can create a negative pressure inside the vacuum tank, thereby drawing external media into the pump chamber of the centrifugal pump through the negative pressure. The liquid level sensor is installed inside the vacuum tank, and its installation height is not lower than the highest point of the pump chamber of the centrifugal pump. The liquid level sensor is used to monitor the liquid level inside the vacuum tank to adapt to the subsequent control components that control the start and stop of the vacuum pump.

2. The self-priming device for pumps according to claim 1, characterized in that, The vacuum tank includes a tank body and a horizontal mounting pipe. The tank body is connected to the middle section of the horizontal mounting pipe. One end of the horizontal mounting pipe is used to connect to the inlet of the centrifugal pump, and the other end is used to connect to the suction pipe.

3. The self-priming device for pumps according to claim 1, characterized in that, The vacuum tank is equipped with a first liquid level sensor and a second liquid level sensor. The first liquid level sensor is located at the bottom of the vacuum tank, and its height is not lower than the highest point of the centrifugal pump chamber. The second liquid level sensor is installed at a higher height than the first liquid level sensor.

4. The self-priming device for pumps according to claim 3, characterized in that, The second liquid level sensor is located at the top of the vacuum tank, and there is a gap between the second liquid level sensor and the top of the vacuum tank.

5. The self-priming device for a pump according to any one of claims 1-4, characterized in that, The vacuum tank is equipped with an air check valve and a gas-liquid separator on the vacuum pipeline connecting it to the vacuum pump.

6. A pump set, characterized in that, include: Drive unit, centrifugal pump, and self-priming device for pump as described in any one of claims 1-5; The drive unit is connected to the input shaft of the centrifugal pump to drive the centrifugal pump to rotate; the drive unit and the vacuum pump are connected by a clutch device, which is used to switch the power transmission state between the drive unit and the vacuum pump; the liquid level sensor is electrically connected to the main control circuit, which is connected to the control circuit of the clutch device, and the main control circuit outputs a control signal to the control circuit of the clutch device to switch the clutch device between engagement and disengagement.

7. The pump set according to claim 6, characterized in that, The outlet of the centrifugal pump is connected to an outlet short pipe, and a side pipe interface is provided on the side wall of the outlet short pipe. A ball valve is installed at the side pipe interface, and the side pipe interface is connected to the shaft seal assembly of the centrifugal pump through a return pipe.

8. The pump set according to claim 6 or 7, characterized in that, A check valve and a solenoid butterfly valve are also installed at the rear end of the outlet short pipe, and the end of the outlet short pipe is connected to the drain pipe.

9. The pump set according to claim 6, characterized in that, The transmission connection structure between the drive device and the vacuum pump is one of the following two types: Structure 1: The output end of the drive device is equipped with a first pulley, and the input shaft of the vacuum pump is equipped with a clutch device, which includes a second pulley; the first pulley and the second pulley are connected by a belt. Structure 2: The drive device is connected to the input shaft of the centrifugal pump, and a first pulley is installed on the pump shaft of the centrifugal pump; a clutch device is installed on the input shaft of the vacuum pump, and the clutch device includes a second pulley; the first pulley and the second pulley are connected by a belt.

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