An ejector device and method for eliminating cavitation in unloading pumps

Abstract

This invention relates to the field of unloading pump technology, and discloses an ejector device and method for eliminating cavitation in unloading pumps. The device includes a base, an unloading pump, a motor, an ejector mechanism, a flow-dividing adjustment mechanism, and a pressure transmission mechanism. The unloading pump and motor are mounted on the base. The unloading pump has an inlet and an outlet. The ejector mechanism is connected to the inlet of the unloading pump and is in communication with the inlet. The flow-dividing adjustment mechanism is connected to the outlet. The flow-dividing adjustment mechanism includes an inlet pipe, an outlet pipe, and a return pipe. A connecting pipe is connected to the end of the return pipe. The pressure transmission mechanism is connected to the end of the ejector mechanism. This invention uses a mechanical linkage structure to achieve real-time sensing of the pump inlet pressure and adaptive distribution of the outlet flow. It eliminates the need for an auxiliary pump, complex pipeline modifications, and an electronically controlled frequency converter system. While reducing system complexity and investment costs, it quickly responds to fluctuations in operating conditions, dynamically stabilizes the pump inlet pressure, and avoids cavitation impact damage to the pump's flow components.

Description

Technical Field

[0001] This invention belongs to the field of unloading pump technology, specifically, it relates to an ejector device and method for eliminating cavitation in unloading pumps. Background Technology

[0002] In the chemical, petroleum, and liquid media storage and transportation industries, unloading pumps are commonly used as core conveying equipment in operations such as tank truck unloading and storage tank transfer. The stable operation of the unloading pump directly determines the working efficiency and safety of the entire unloading system. During actual unloading, the inlet pressure of the unloading pump is easily lowered than the critical safety value due to fluctuations in the suction liquid level, changes in pipeline resistance, and the vaporization characteristics of the medium itself. This can lead to medium vaporization, bubble collapse impacting the pump body flow channel and impeller, resulting in cavitation. Currently, the industry typically improves the inlet pressure conditions by increasing the suction pipe diameter, reducing the pump body installation height, and adding a pre-installed auxiliary pump to mitigate the adverse effects of cavitation.

[0003] However, pipeline modification or pump installation location adjustment not only involves a large amount of work and high modification costs, but is also greatly affected by the properties of the medium and fluctuations in on-site operating conditions. It cannot fundamentally solve the problem of insufficient inlet pressure. Adding a pre-auxiliary pump will increase the structural complexity of the system and equipment investment, while also increasing maintenance and replacement costs and on-site operation and maintenance workload.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: An ejector device for eliminating cavitation in a truck unloading pump includes a base, a truck unloading pump, a motor, an ejector mechanism, a flow-dividing adjustment mechanism, and a pressure transmission mechanism. The base houses the truck unloading pump and the motor. A rotating shaft is connected to the motor, and a rotating shaft is connected to the truck unloading pump. A coupling connects the rotating shaft and the rotating shaft. The truck unloading pump has an inlet and an outlet. The inlet of the truck unloading pump is connected to the ejector mechanism, and the output end of the ejector mechanism is connected to the inlet. The ejector mechanism internally includes a nozzle, a mixing chamber, a throat, and a diffuser, arranged sequentially. The outlet of the truck unloading pump is connected to the flow-dividing adjustment mechanism, which includes an inlet pipe, an outlet pipe, and a return pipe. The inlet pipe is connected to the outlet, and the end of the return pipe is connected to a connecting pipe, which is connected to the ejector mechanism. The end of the ejector mechanism is connected to the pressure transmission mechanism, which includes a detection pipe and a pressure sensor. The detection pipe is connected to the end of the ejector mechanism, and the pressure sensor is installed on the detection pipe.

[0006] In a preferred embodiment of the present invention, the ejector mechanism includes an ejector tube with a high-pressure inlet and a low-pressure inlet. The nozzle is installed at the high-pressure inlet and is connected to a connecting pipe. The low-pressure inlet is connected to a mixing chamber. The end of the ejector tube is also provided with an ejector outlet, which is connected to the suction port on the unloading pump.

[0007] In a preferred embodiment of the present invention, the diversion adjustment mechanism includes a three-way pipe, and a ball core is rotatably installed inside the three-way pipe. The ball core has an inflow channel, an outflow channel and a return channel that are interconnected. The inflow channel is connected to the inflow pipe, the outflow channel is connected to the outflow pipe, and the return channel is connected to the return pipe.

[0008] In a preferred embodiment of the present invention, the upper end of the ball core is connected to a drive shaft, the drive shaft extends vertically to the outside of the tee tube, and the drive shaft is rotatably connected to the tee tube.

[0009] In a preferred embodiment of the present invention, the pressure transmission mechanism includes a piston cylinder, the piston cylinder is connected to the end of the ejector mechanism, the piston cylinder and the ejector mechanism are connected, a piston plate is slidably installed inside the piston cylinder, a piston rod is connected to the middle of the piston plate, and a connecting rod is connected to the end of the piston rod.

[0010] In a preferred embodiment of the present invention, a movable plate is connected to the end of the connecting rod, a cam is mounted on the movable plate, a cam groove is provided at the end of the transmission shaft, and the cam is slidably disposed inside the cam groove.

[0011] In a preferred embodiment of the present invention, the movable plate is slidably mounted on the end of the transmission shaft.

[0012] In a preferred embodiment of the present invention, a spring is installed inside the piston cylinder, the spring is movably sleeved on the piston rod, one end of the spring abuts against the piston plate, and the other end abuts against the end of the piston cylinder.

[0013] In a preferred embodiment of the present invention, the base is connected to a support column for supporting the ejector mechanism, the flow adjustment mechanism and the pressure transmission mechanism.

[0014] The method for eliminating cavitation in unloading pumps comprises the following steps: S1: Start the motor and drive the unloading pump to operate through the coupling, so that the unloading pump enters the working state; S2: High-pressure fluid enters the high-pressure inlet of the ejector mechanism through the return pipe and connecting pipe, and forms a high-speed jet through the nozzle; S3: The high-speed jet creates negative pressure in the mixing chamber, drawing in the low-pressure unloading fluid through the low-pressure inlet and mixing it with the high-pressure jet; S4: After being pressurized by the throat and diffuser, the mixed fluid is sent into the suction port of the unloading pump through the ejector outlet; S5: The high-pressure fluid discharged from the unloading pump enters the tee pipe through the inlet pipe, and the flow is distributed by the ball core; S6: The detection tube transmits the unloading pump inlet pressure to the piston cylinder, pushing the piston plate and piston rod to move; S7: The piston rod drives the transmission shaft to rotate through the connecting rod and cam, adjusting the opening of the ball core, changing the flow area of ​​the discharge channel and return channel, adaptively maintaining the inlet pressure of the unloading pump, and eliminating cavitation.

[0015] Compared with the prior art, the present invention has the following advantages: This invention employs a mechanical linkage structure to achieve real-time sensing of pump inlet pressure and adaptive distribution of outlet flow. It eliminates the need for additional auxiliary pumps, complex pipeline modifications, and electronic control frequency conversion systems. While reducing system complexity and initial investment costs, it rapidly responds to fluctuations in operating conditions, dynamically stabilizes pump inlet pressure, and ensures that the unloading pump always operates efficiently under design conditions, improving unloading efficiency and preventing cavitation from impacting and damaging the pump's flow components.

[0016] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0017] In the attached diagram: Figure 1 A three-dimensional diagram of an ejector device for eliminating cavitation in unloading pumps; Figure 2 This is a schematic diagram of the installation of the ejector mechanism, the flow regulation mechanism, and the pressure transmission mechanism of an ejector device for eliminating cavitation in unloading pumps. Figure 3 A cross-sectional view of the ejector mechanism of an ejector device for eliminating cavitation in unloading pumps; Figure 4 Cross-sectional view of the flow regulation mechanism of an ejector device for eliminating cavitation in unloading pumps Figure 1 ; Figure 5 Cross-sectional view of the flow regulation mechanism of an ejector device for eliminating cavitation in unloading pumps Figure 2 ; Figure 6 A schematic diagram of the internal structure of the flow regulation mechanism of an ejector device for eliminating cavitation in unloading pumps; Figure 7 An ejector device for eliminating cavitation in unloading pumps Figure 6 Enlarged view of point A in the middle; Figure 8 A three-dimensional diagram of the ball core of an ejector device for eliminating cavitation in unloading pumps.

[0018] In the diagram: 1. Base; 2. Unloading pump; 3. Motor; 4. Rotating shaft; 5. Rotating shaft; 6. Coupling; 7. Suction inlet; 8. Discharge outlet; 9. Ejector tube; 91. Throat tube; 92. Diffuser tube; 93. Mixing chamber; 10. Nozzle; 11. High-pressure inlet; 12. Low-pressure inlet; 13. Ejector outlet; 14. Detection tube; 15. Pressure sensor; 16. T-connector; 17. Inflow tube; 18. Discharge tube; 19. Return tube; 20. Ball core; 21. Inflow channel; 22. Discharge channel; 23. Return channel; 24. Drive shaft; 25. Cam groove; 26. Moving plate; 27. Cam; 28. Connecting rod; 29. ​​Piston rod; 30. Piston cylinder; 31. Piston plate; 32. Spring; 33. Support column; 34. Connecting tube. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention.

[0020] like Figures 1 to 8 As shown, an ejector device and method for eliminating cavitation in a truck unloading pump includes a base 1, a truck unloading pump 2, a motor 3, an ejector mechanism, a flow control mechanism, and a pressure transmission mechanism. The truck unloading pump 2 and motor 3 are mounted on the base 1. A rotating shaft 5 is connected to the motor 3, and a rotating shaft 4 is connected to the truck unloading pump 2. A coupling 6 is connected to the rotating shaft 4 and rotating shaft 5. The truck unloading pump 2 has a suction port 7 and a discharge port 8. The suction port 7 of the truck unloading pump 2 is connected to the ejector mechanism, and the output end of the ejector mechanism is connected to the suction port 7. The ejector mechanism contains, sequentially arranged, [missing information - likely components]. The nozzle 10, mixing chamber 93, throat 91 and diffuser 92, and the outlet 8 of the unloading pump 2 are connected to a flow diversion adjustment mechanism. The flow diversion adjustment mechanism includes an inflow pipe 17, an outlet pipe 18 and a return pipe 19. The inflow pipe 17 is connected to the outlet 8. The end of the return pipe 19 is connected to a connecting pipe 34. The connecting pipe 34 is connected to the ejector mechanism. The end of the ejector mechanism is connected to a pressure transmission mechanism. The pressure transmission mechanism includes a detection pipe 14 and a pressure sensor 15. The detection pipe 14 is connected to the end of the ejector mechanism. The pressure sensor 15 is installed on the detection pipe 14. In this setup, base 1 provides stable mounting support for unloading pump 2, motor 3 and various functional mechanisms. Motor 3 transmits power synchronously to unloading pump 2 through coupling 6, driving unloading pump 2 to complete fluid delivery. Ejector mechanism is used to pressurize the fluid entering the suction port 7 of unloading pump 2. Flow diversion adjustment mechanism is used to distribute the flow direction of the fluid discharged from unloading pump 2. Pressure transmission mechanism is used to sense the pressure change at the inlet of unloading pump 2 and drive the flow diversion adjustment mechanism to operate. Pressure sensor 15 is used to assist in monitoring the pump inlet pressure.

[0021] like Figures 1 to 8As shown, in a specific embodiment, the ejector mechanism includes an ejector tube 9, which has a high-pressure inlet 11 and a low-pressure inlet 12. A nozzle 10 is installed at the high-pressure inlet 11, and the high-pressure inlet 11 is connected to the connecting pipe 34. The low-pressure inlet 12 is connected to the mixing chamber 93. An ejector outlet 13 is also provided at the end of the ejector tube 9, and the ejector outlet 13 is connected to the suction port 7 on the unloading pump 2. In this configuration, after the high-pressure fluid enters the high-pressure inlet 11 through the connecting pipe 34, the pressure energy is converted into kinetic energy through the nozzle 10 to form a high-speed jet. A negative pressure is generated in the mixing chamber 93, and the external low-pressure unloading fluid is drawn in through the low-pressure inlet 12. After the high-speed jet and the low-pressure unloading fluid are initially mixed in the mixing chamber 93, they enter the throat 91 to complete momentum exchange. Then, the kinetic energy is converted into pressure energy through the diffuser 92 to achieve pressurization. Finally, the pressurized fluid is sent to the suction port 7 of the unloading pump 2 through the ejector outlet 13 to increase the pump inlet pressure.

[0022] like Figures 1 to 8 As shown, the flow regulation mechanism further includes a three-way pipe 16, inside which a ball core 20 is rotatably mounted. The ball core 20 has interconnected inflow channels 21, 22, and 23. Inflow channel 21 is connected to inflow pipe 17, 22 to discharge pipe 18, and 23 to return pipe 19. In this configuration, the three-way pipe 16 provides space for the installation and rotation of the ball core 20. The ball core 20, through its rotation, changes the conduction area ratio of the inflow channel 21, discharge channel 22, and return channel 23, guiding the high-pressure fluid entering from inflow pipe 17 to discharge pipe 18 and return pipe 19 respectively, thus achieving dynamic distribution of the main unloading flow rate and the ejector return flow rate.

[0023] like Figures 1 to 8 As shown, furthermore, a drive shaft 24 is connected to the upper end of the ball core 20. The drive shaft 24 extends vertically to the outside of the three-way pipe 16, and the drive shaft 24 is rotatably connected to the three-way pipe 16. In this configuration, the drive shaft 24 is connected to the ball core 20, transmitting rotational power to the ball core 20, causing the ball core 20 to rotate inside the three-way pipe 16, thereby changing the conduction state of each flow channel and providing power input for flow distribution adjustment.

[0024] like Figures 1 to 8As shown, the pressure transmission mechanism further includes a piston cylinder 30, with the ejector mechanism connected to the end of the piston cylinder 30. The piston cylinder 30 is connected to the ejector mechanism. A piston plate 31 is slidably mounted inside the piston cylinder 30. A piston rod 29 is connected to the middle of the piston plate 31, and a connecting rod 28 is connected to the end of the piston rod 29. In this configuration, the piston cylinder 30 is used to accommodate the piston plate 31 and form a pressure sensing chamber. The fluid pressure acts directly on the piston plate 31, pushing the piston plate 31 to slide along the inner wall of the piston cylinder 30, thereby causing the piston rod 29 to produce linear displacement. The piston rod 29 transmits the linear displacement through the connecting rod 28, realizing the conversion of pressure signal into mechanical displacement.

[0025] like Figures 1 to 8 As shown, further, a movable plate 26 is connected to the end of the connecting rod 28, and a cam 27 is mounted on the movable plate 26. A cam groove 25 is provided at the end of the transmission shaft 24, and the cam 27 is slidably disposed inside the cam groove 25. In this configuration, the connecting rod 28 moves synchronously with the piston rod 29, causing the movable plate 26 to produce linear motion, which causes the cam 27 to slide along the cam groove 25 at the end of the transmission shaft 24, converting the linear displacement of the movable plate 26 into the rotational motion of the transmission shaft 24. This, in turn, drives the ball core 20 to rotate through the transmission shaft 24, thereby realizing the automatic adjustment of flow distribution.

[0026] like Figures 1 to 8 As shown, the movable plate 26 is further slidably mounted on the end of the drive shaft 24. In this configuration, the movable plate 26 is slidably mounted on the end of the drive shaft 24 to restrict its own direction of movement and ensure that the movement trajectory of the cam 27 within the cam groove 25 is accurate.

[0027] like Figures 1 to 8 As shown, a spring 32 is further installed inside the piston cylinder 30. The spring 32 is movably sleeved on the piston rod 29, with one end of the spring 32 abutting against the piston plate 31 and the other end abutting against the end of the piston cylinder 30. In this configuration, the spring 32 undergoes elastic deformation as the piston plate 31 moves, providing a reverse restoring force to the piston plate 31. When the pump inlet pressure decreases, the spring force of the spring 32 pushes the piston plate 31 to move in the opposite direction, realizing the reverse adjustment action when the pressure decreases.

[0028] like Figures 1 to 8 As shown, the base 1 is further equipped with a support column 33 for supporting the ejector mechanism, the flow adjustment mechanism, and the pressure transmission mechanism. In this configuration, the support column 33 provides stable support for the ejector mechanism, the flow adjustment mechanism, and the pressure transmission mechanism.

[0029] The present invention also discloses a method for eliminating cavitation in unloading pumps, the steps of which are as follows: S1: Start motor 3, which drives unloading pump 2 to operate through coupling 6, so that unloading pump 2 enters working state; S2: High-pressure fluid enters the high-pressure inlet 11 of the ejector mechanism through the return pipe 19 and the connecting pipe 34, and forms a high-speed jet through the nozzle 10; S3: The high-speed jet creates a negative pressure in the mixing chamber 93, drawing in the low-pressure unloading fluid through the low-pressure inlet 12 and mixing it with the high-pressure jet; S4: After being pressurized by the throat 91 and the diffuser 92, the mixed fluid is sent into the suction port 7 of the unloading pump 2 through the ejector outlet 13; S5: The high-pressure fluid discharged from the unloading pump 2 enters the three-way pipe 16 through the inflow pipe 17, and the flow is distributed by the ball core 20; S6: The detection tube 14 transmits the inlet pressure of the unloading pump 2 to the piston cylinder 30, which pushes the piston plate 31 and the piston rod 29 to move. S7: The piston rod 29 drives the transmission shaft 24 to rotate through the connecting rod 28 and the cam 27, adjusts the opening of the ball core 20, changes the flow area of ​​the discharge channel 22 and the return channel 23, adaptively maintains the inlet pressure of the unloading pump 2, and eliminates cavitation.

[0030] The implementation principle of the ejector device and method for eliminating cavitation in unloading pumps in this embodiment is as follows: When the device is working, the motor 3 first outputs power, which is transmitted through the coupling 6 to drive the rotating shaft 5 and the rotating shaft 4 to rotate synchronously, thereby driving the unloading pump 2 to work. After the unloading pump 2 starts running, the entire ejector pressurization process starts working synchronously. High-pressure fluid enters the nozzle 10 inside the ejector tube 9 from the high-pressure inlet 11. When the fluid flows through the constriction structure of the nozzle 10, its own pressure energy is gradually converted into high-speed kinetic energy, forming a high-speed jet beam that is continuously sprayed outward. A high-speed jet flows rapidly within the mixing chamber 93 of the ejector tube 9, creating a negative pressure environment in the mixing chamber 93 region. Utilizing this negative pressure adsorption, the low-pressure unloading medium remaining stationary inside the tank truck is naturally drawn into the mixing chamber 93 through the low-pressure inlet 12. The drawn-in low-pressure medium and the high-speed, high-pressure fluid ejected from the nozzle 10 initially merge and mix within the mixing chamber 93, then flow together into the throat 91. Within the regular flow channel of the throat 91, momentum and velocity exchange are fully completed, gradually causing the flow velocities of the two fluids to become uniform, forming a stable mixed fluid medium. The uniformly mixed fluid continues to flow forward into the diffuser tube 92. With the help of the gradually expanding flow channel structure of the diffuser tube 92, the flow velocity of the mixed fluid gradually decreases, and the fluid kinetic energy is continuously converted into pressure energy, achieving a pressure stabilization and boosting effect on the medium itself. After pressure boosting and stabilization, the mixed fluid flows out from the ejector outlet 13 and is transported to the suction inlet 7 of the unloading pump 2, entering the unloading pump 2.

[0031] The unloading pump 2 further pressurizes the mixed fluid entering the pump, increasing the fluid pressure. The pressurized high-pressure fluid is discharged from the outlet 8 of the unloading pump 2 and then flows into the three-way pipe 16 through the inflow pipe 17. The ball core 20 inside the three-way pipe 16 receives the high-pressure fluid through the inflow channel 21. By changing the internal flow channel conduction ratio through the rotation angle of the ball core 20, the flow rate of the incoming high-pressure fluid is automatically distributed. Part of the fluid flows through the outlet channel 22 to the outlet pipe 18 and is continuously transported to the designated target storage tank to complete the routine unloading and transportation operation. The other part of the fluid is diverted through the return channel 23 into the return pipe 19 and then back to the high-pressure inlet 11 of the ejector tube 9 through the connecting pipe 34, continuously supplying high-pressure working fluid to the nozzle 10 inside the ejector tube 9, thus forming an uninterrupted self-circulating ejector working loop to ensure the continuous and stable operation of the ejector structure.

[0032] Throughout the unloading operation, the fluid pressure at the inlet of the unloading pump 2 is transmitted to the piston cylinder 30 and acts on the piston plate 31. When the unloading condition and the fluid pressure at the inlet of the unloading pump 2 are higher than the cavitation critical set pressure value, the thrust generated by the fluid pressure is greater than the preload force of the spring 32, pushing the piston plate 31 to move inside the piston cylinder 30 and compressing the spring 32. Simultaneously, this drives the piston rod 29 to move upward. During the movement, the piston rod 29 drives the connecting rod 28 to move synchronously, thereby pulling the moving plate 26 and the cam 27 to move in the cam groove 25, converting linear motion into rotational power and driving the transmission shaft 24 to rotate. The transmission shaft 24 then drives the ball core 20 inside the three-way pipe 16 to rotate and adjust. At this time, the ball core 20 is adjusted to a suitable working angle, so that the discharge channel 22 maintains a large opening and the return channel 23 maintains a small opening. Most of the high-pressure fluid is transported out through the discharge pipe 18 to complete the unloading, and only a small portion of the fluid participates in the ejection cycle through the return pipe 19, balancing unloading efficiency and basic ejection requirements.

[0033] When fluctuations in the unloading conditions, changes in liquid level, or alterations in pipeline resistance cause a drop in the inlet fluid pressure of the unloading pump 2, the fluid thrust acting on the piston plate 31 inside the piston cylinder 30 decreases accordingly. The spring 32 pushes the piston plate 31 to move in the opposite direction within the piston cylinder 30, simultaneously causing the piston rod 29 to move in the opposite direction. The piston rod 29, through the connecting rod 28, pulls the cam 27 to move in the opposite direction in the cam groove 25, thereby driving the transmission shaft 24 to rotate the ball core 20 in the opposite direction to adjust and reduce the opening of the discharge channel 22 and increase the opening of the return channel 23. After the flow distribution ratio is changed, a larger proportion of the high-pressure fluid is diverted into the return pipe 19 and transported to the high-pressure inlet 11 of the ejector pipe 9 via the connecting pipe 34. This increases the flow rate and pressure of the high-pressure working fluid in the ejector pipe, enhances the overall jet negative pressure capability of the ejector pipe 9, and adsorbs more low-pressure unloading media from the tanker into the mixing chamber 93. After mixing through the throat pipe 91 and pressurization through the diffuser pipe 92, the fluid pressure at the inlet of the unloading pump 2 is increased, keeping the pump inlet pressure above the allowable cavitation safety value. This prevents the vaporization of the medium and the collapse of bubbles inside the unloading pump 2, suppresses and eliminates pump cavitation problems, and works in conjunction with the pressure sensor 15 to monitor the pressure fluctuations inside the pipeline in real time.

[0034] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ejector device for eliminating cavitation in a truck unloading pump, comprising a base (1), a truck unloading pump (2), a motor (3), an ejector mechanism, a flow diversion adjustment mechanism, and a pressure transmission mechanism, characterized in that, The base (1) is equipped with a truck unloading pump (2) and a motor (3). A rotating shaft (5) is connected to the motor (3), and a rotating shaft (4) is connected to the truck unloading pump (2). A coupling (6) is connected to the rotating shaft (4) and the rotating shaft (5). The truck unloading pump (2) is provided with a suction port (7) and a discharge port (8). The suction port (7) of the truck unloading pump (2) is connected to an ejector mechanism. The output end of the ejector mechanism is connected to the suction port (7). The ejector mechanism is provided with a nozzle (10), a mixing chamber (93), a throat (91), and a diffuser (92) arranged in sequence. The discharge port (8) of the unloading pump (2) is connected to a diversion adjustment mechanism. The diversion adjustment mechanism includes an inflow pipe (17), a discharge pipe (18), and a return pipe (19). The inflow pipe (17) is connected to the discharge port (8). The end of the return pipe (19) is connected to a connecting pipe (34). The connecting pipe (34) is connected to an ejector mechanism. The end of the ejector mechanism is connected to a pressure transmission mechanism. The pressure transmission mechanism includes a detection pipe (14) and a pressure sensor (15). The detection pipe (14) is connected to the end of the ejector mechanism. The pressure sensor (15) is installed on the detection pipe (14).

2. The ejector device for eliminating cavitation in unloading pumps according to claim 1, characterized in that, The ejector mechanism includes an ejector tube (9), which has a high-pressure inlet (11) and a low-pressure inlet (12). The nozzle (10) is installed at the high-pressure inlet (11), and the high-pressure inlet (11) is connected to the connecting pipe (34). The low-pressure inlet (12) is connected to the mixing chamber (93). The end of the ejector tube (9) also has an ejector outlet (13), which is connected to the suction port (7) on the unloading pump (2).

3. The ejector device for eliminating cavitation in unloading pumps according to claim 1, characterized in that, The diversion adjustment mechanism includes a three-way pipe (16), inside which a ball core (20) is rotatably installed. Inside the ball core (20) are interconnected inflow channels (21), outflow channels (22) and return channels (23). The inflow channels (21) are connected to the inflow pipe (17), the outflow channels (22) are connected to the outflow pipe (18), and the return channels (23) are connected to the return pipe (19).

4. The ejector device for eliminating cavitation in unloading pumps according to claim 3, characterized in that, The upper end of the ball core (20) is connected to a drive shaft (24), which extends vertically to the outside of the three-way pipe (16) and is rotatably connected to the three-way pipe (16).

5. The ejector device for eliminating cavitation in unloading pumps according to claim 1, characterized in that, The pressure transmission mechanism includes a piston cylinder (30), the piston cylinder (30) is connected to the end of the ejector mechanism, the piston cylinder (30) is connected to the ejector mechanism, a piston plate (31) is slidably installed inside the piston cylinder (30), a piston rod (29) is connected to the middle of the piston plate (31), and a connecting rod (28) is connected to the end of the piston rod (29).

6. The ejector device for eliminating cavitation in unloading pumps according to claim 5, characterized in that, The connecting rod (28) is connected to a movable plate (26) at its end. A cam (27) is mounted on the movable plate (26). A cam groove (25) is opened at the end of the transmission shaft (24). The cam (27) is slidably disposed inside the cam groove (25).

7. The ejector device for eliminating cavitation in unloading pumps according to claim 6, characterized in that, The movable plate (26) is slidably mounted on the end of the drive shaft (24).

8. The ejector device for eliminating cavitation in unloading pumps according to claim 5, characterized in that, A spring (32) is installed inside the piston cylinder (30). The spring (32) is movably sleeved on the piston rod (29). One end of the spring (32) abuts against the piston plate (31), and the other end abuts against the end of the piston cylinder (30).

9. The ejector device for eliminating cavitation in unloading pumps according to claim 8, characterized in that, The base (1) is connected to a support column (33) for supporting the ejector mechanism, the diversion adjustment mechanism and the pressure transmission mechanism.

10. A method for eliminating cavitation in unloading pumps, characterized in that, An ejector device for eliminating cavitation in an unloading pump according to any one of claims 1-9, wherein the method for eliminating cavitation in an unloading pump comprises the following steps: S1: Start the motor (3) and drive the unloading pump (2) to run through the coupling (6) to put the unloading pump (2) into working state; S2: High-pressure fluid enters the high-pressure inlet (11) of the ejector mechanism through the return pipe (19) and the connecting pipe (34), and forms a high-speed jet through the nozzle (10); S3: The high-speed jet creates a negative pressure in the mixing chamber (93), drawing in the low-pressure unloading fluid through the low-pressure inlet (12) and mixing it with the high-pressure jet; S4: After the mixed fluid is pressurized by the throat (91) and the diffuser (92), it is sent into the suction port (7) of the unloading pump (2) through the ejector outlet (13). S5: The high-pressure fluid discharged by the unloading pump (2) enters the three-way pipe (16) through the inflow pipe (17), and the flow is distributed by the ball core (20); S6: The detection tube (14) transmits the inlet pressure of the unloading pump (2) to the piston cylinder (30), which pushes the piston plate (31) and piston rod (29) to move; S7: The piston rod (29) drives the transmission shaft (24) to rotate through the connecting rod (28) and the cam (27), adjusts the opening of the ball core (20), changes the flow area of ​​the discharge channel (22) and the return channel (23), adaptively maintains the inlet pressure of the unloading pump (2), and eliminates cavitation.

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