A pusher centrifuge pressure reversing device and a control method thereof

Abstract

The application discloses a pressure reversing device of a pusher centrifuge and a control method thereof, and is characterized by further comprising an oil tank, an oil pump connected with the oil tank through a pipeline, a valve island connected with the oil pump through a pipeline, an oil inlet pipeline and an oil return pipeline arranged on the valve island, a main valve arranged on the valve island and communicated with the oil inlet pipeline and used for controlling oil supply to a left end pushing chamber or a right end pushing chamber, and a pilot valve arranged on the main valve and communicated with the oil inlet pipeline and used for controlling reversing of the main valve and controlling reversing of a piston. After the piston in the oil cylinder moves to a position, the piston cannot be switched due to the fact that the oil inlet pipeline is not switched and the oil inlet pipeline is not communicated, so that the pressure of the hydraulic system is rapidly increased. The reversing of the main valve and the pilot valve is controlled by using the rapidly increased pressure, and then the reversing of the piston is controlled. The reversing signal is generated by the increase of the pressure in the hydraulic system after the piston moves to the position, so that the switching of the piston after the piston moves to the position can be effectively ensured, and the problem of short pushing of the pusher centrifuge is avoided.

Description

Technical Field

[0001] This invention relates to a centrifuge reversing mechanism, specifically a pressure reversing device for a pusher centrifuge and its control method. Background Technology

[0002] Current centrifuges using pusher centrifuges employ purely mechanical structures to control hydraulic circuits for pusher reversal. The most common method is to integrate the reversal mechanism into the cylinder, utilizing the cylinder's stroke. The reversal signal is generated by a guide plunger colliding within the cylinder, causing it to move in the opposite direction to the piston. This structure has significant drawbacks. When the guide plunger wears down during operation, increasing its clearance, it experiences a reverse impact force upon colliding with the cylinder. As the resistance decreases due to wear, the guide plunger moves more rapidly in the opposite direction to the piston, causing premature piston reversal and shortening the pusher stroke. Furthermore, when this structure malfunctions, troubleshooting and analysis are difficult, disassembly and repair are cumbersome, and residual hydraulic oil in the hydraulic system during disassembly and repair can contaminate the work site. Furthermore, the aforementioned reversing mechanisms all suffer from a problem under high pressure: the valve core or reverse sleeve controlling the piston reversing oil circuit experiences significantly increased force under high pressure, leading to increased movement speed of the valve core or reverse sleeve. This reduces the time for hydraulic oil to enter both ends of the piston, causing the piston to not reach its designated position and resulting in short-push movements in the centrifuge. Therefore, a pressure reversing device and its control method for a centrifuge are proposed. Summary of the Invention

[0003] The purpose of this invention is to solve the above problems by proposing a pressure reversing device for a pusher centrifuge and its control method.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a control method for a pressure reversing device of a feeding centrifuge, characterized in that: the control method is as follows: a. Start the oil pump. The oil pump draws hydraulic oil from the oil tank and supplies it to the valve island's oil inlet circuit. b. Part of the hydraulic oil in the oil inlet circuit enters the main valve inlet chamber, and part enters the pilot valve inlet chamber; c. When the left end of the pilot valve core is in contact with the left valve seat, the pilot valve inlet chamber on the pilot valve core is connected to the pilot valve annular chamber on the right side; d. After the hydraulic oil enters the right chamber of the main valve through the pilot valve inlet chamber, the pilot valve ring chamber, and the right reversing oil circuit, it pushes the main valve core to move to the left; e. After the main valve core moves to the left until the left end of the main valve core fits against the left side of the main valve chamber, the main valve inlet ring chamber on the main valve core is connected to the left end oil supply chamber; f. Hydraulic oil is supplied to the left-end push chamber through the main valve inlet ring chamber, the left-end supply chamber, and the oil passage, and then pushes the piston to move to the right. g. After the piston moves to the right and reaches the bottom of the right end, the hydraulic system is blocked. Under continuous oil supply, the system pressure rises. When the system pressure rises to the set pressure of the right-end safety relief valve; h. When the right-end safety relief valve on the pilot valve is opened, hydraulic oil enters the right side of the pilot valve chamber through the pilot valve inlet chamber, the pilot valve ring chamber, the small valve core reversing inlet channel, and the right-end safety relief valve, pushing the small valve core to move to the left until it is in contact with the small valve core limit piece; i. At this time, the pilot valve inlet chamber, pilot valve inlet channel, small valve core inlet chamber and pilot valve left end inlet / outlet port are connected, pushing the pilot valve core to move to the right until the right end of the pilot valve core is in contact with the right valve seat; during the process of the pilot valve core moving to the right, the pilot valve right end inlet / outlet port, small valve core return chamber, pilot valve return port, right reversing oil circuit, pilot valve ring chamber on the right side, pilot valve return chamber and return oil circuit are connected; j. The pilot valve inlet chamber on the pilot valve core and the pilot valve ring chamber on the left side are connected to the left reversing oil circuit; k. After the hydraulic oil enters the left chamber of the main valve through the pilot valve inlet chamber, the pilot valve ring chamber, and the left reversing oil circuit, it pushes the main valve core to move to the right; 1. After the main valve core moves to the right until the right end of the main valve core fits against the right side of the main valve chamber, the main valve inlet ring chamber on the main valve core is connected to the right end oil supply chamber; m. Hydraulic oil is supplied to the right-end push chamber through the main valve inlet ring chamber, the right-end supply chamber, and the oil passage, and then pushes the piston to move to the left to achieve reversal; n. After the piston moves to the bottom of the left end, the hydraulic system is blocked. Under continuous oil supply, the system pressure rises. When the system pressure rises to the set pressure of the safety relief valve at the left end; o. The left-end safety relief valve on the pilot valve opens, and the hydraulic oil enters the left side of the pilot valve chamber through the pilot valve inlet chamber, the pilot valve ring chamber, the small valve core reversing inlet channel, and the left-end safety relief valve, pushing the small valve core to move to the right until it is in contact with the small valve core limit piece; p. At this time, the pilot valve inlet chamber, pilot valve inlet channel, small valve core inlet chamber and right end inlet / outlet port of the pilot valve are connected, pushing the pilot valve core to move to the left until the left end of the pilot valve core is in contact with the left valve seat; during the process of the pilot valve core moving to the left, the left end inlet / outlet port of the pilot valve, the small valve core return chamber, the pilot valve return port, the left reversing oil circuit, the pilot valve annular cavity on the left side, the pilot valve return chamber and the return oil circuit are connected; q. The pilot valve inlet chamber on the pilot valve core and the pilot valve ring chamber on the right side are connected to the right reversing oil circuit, which controls the main valve to reverse again. After the main valve reverses again, it controls the piston to reverse again. r. During operation, if the oil pressure reaches the set pressure of the pilot relief valve, the pilot relief valve opens, and the pumped hydraulic oil returns to the oil tank after passing through the pilot relief valve.

[0005] A pressure reversing device for a pusher centrifuge, characterized by including an oil cylinder, a piston disposed in the oil cylinder, a pusher shaft connected to the piston, and a rotary joint connected to the oil cylinder, wherein the piston forms a left-end pusher chamber and a right-end pusher chamber in the oil cylinder. It also includes an oil tank, an oil pump connected to the oil tank via a pipeline, a valve island connected to the oil pump via a pipeline, an inlet oil passage and a return oil passage set on the valve island, a main valve set on the valve island and connected to the inlet oil passage for controlling the oil supply to the left or right end of the thrust chamber, and a pilot valve set on the main valve and connected to the inlet oil passage for controlling the main valve to switch direction and controlling the piston to switch direction.

[0006] In one embodiment, the main valve includes a main valve body connected to the valve island and communicating with the oil inlet passage of the valve island, a main valve cavity disposed in the main valve body, and a main valve core slidably connected in the main valve cavity for controlling the direction of the oil passage. The main valve forms a main valve left cavity and a main valve right cavity at both ends of the main valve core. The pilot valve includes a pilot valve body connected to the main valve body and communicating with the oil inlet passage of the valve island, a pilot valve cavity disposed on the pilot valve body, a pilot valve core slidably connected in the pilot valve body for controlling the direction of movement of the main valve core, and a small valve core slidably connected in the pilot valve core for controlling the direction of movement of the pilot valve core. It also includes a left valve seat and a right valve seat disposed in the pilot valve body, as well as small valve core limiting components connected to both ends of the pilot valve core; The main valve body and the pilot valve body are provided with a left reversing oil passage that communicates with the left chamber of the main valve and a right reversing oil passage that communicates with the right chamber of the main valve.

[0007] More preferably, the main valve body is provided with a left-end oil supply chamber and a right-end oil supply chamber that communicate with the main valve chamber, and the valve island is provided with oil passages that communicate with the left-end oil supply chamber and the right-end oil supply chamber respectively. The oil passage that communicates with the left-end oil supply chamber is connected to the left-end propulsion chamber through a pipeline, and the oil passage that communicates with the right-end oil supply chamber is connected to the right-end propulsion chamber through a pipeline.

[0008] Further preferably, it also includes a main valve inlet chamber disposed on the main valve body and connected to the inlet oil passage on the valve island, a main valve inlet ring chamber disposed on the main valve core and connected to the main valve inlet chamber, a return oil passage disposed on the valve island, a main valve return oil chamber disposed on the main valve body and connected to the return oil passage, and a main valve return oil ring chamber disposed on both sides of the main valve inlet ring chamber and connected to the main valve return oil chamber.

[0009] A further preferred embodiment includes a cooler connected to the return oil line via a pipeline, and the cooler is connected to the oil tank via a pipeline.

[0010] A further preferred embodiment includes a small valve core reversing oil inlet channel, a small valve core reversing oil return channel disposed on the pilot valve body, and a left-end safety relief valve and a right-end safety relief valve connected to the pilot valve for controlling the opening and closing of the small valve core reversing oil inlet channel and the small valve core reversing oil return channel. The small valve core reversing oil return channel is connected to the pilot valve cavity, the small valve core reversing oil inlet channel on the left side is connected to the left reversing oil circuit, and the small valve core reversing oil inlet channel on the right side is connected to the right reversing oil circuit. Damping components are installed in both the small valve core reversing return oil channel and the small valve core reversing inlet oil channel. The damping components have damping holes, and the diameter of the damping hole on the damping component in the small valve core reversing inlet oil channel is larger than that of the damping hole on the damping component in the small valve core reversing return oil channel.

[0011] Further preferably, it also includes a pilot valve inlet chamber disposed on the pilot valve body and connected to the inlet oil passage, a pilot valve annular cavity disposed on the pilot valve core and connected to the pilot valve inlet chamber, and a pilot valve return oil cavity disposed on both sides of the pilot valve annular cavity and connected to the return oil passage on the pilot valve body. It also includes a small valve core oil inlet chamber on the small valve core, small valve core return chambers on both sides of the small valve core oil inlet chamber on the small valve core, a pilot valve oil inlet channel on the pilot valve core for connecting the pilot valve oil inlet chamber and the small valve core oil inlet chamber, pilot valve left end oil inlet and outlet holes and pilot valve right end oil inlet and outlet holes on the pilot valve core for connecting the small valve core oil return chamber and the pilot valve return hole on the pilot valve core.

[0012] It also includes a pilot relief valve connected to the valve island and communicating with the oil inlet and return channels.

[0013] It also includes a speed control valve that connects the oil inlet circuit of the valve island and the oil tank, and is used to control the amount of hydraulic oil entering the oil cylinder to adjust the number of times the pusher centrifuge pushes the material.

[0014] The beneficial effects of this invention are as follows: With the design of this invention, after the piston moves to the position in the oil cylinder, the oil circuit is blocked because the piston has not switched, causing the hydraulic system pressure to rise rapidly. The rapidly rising pressure is used to control the switching of the main valve and the pilot valve, thereby controlling the switching of the piston. The increase in pressure in the hydraulic system after the piston moves to the position generates a switching signal, which can effectively ensure that the switching is carried out only after the piston moves to the position, thus eliminating the problem of short-push in the pusher centrifuge. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the hydraulic principle of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention; Figure 3 This is a partial cross-sectional structural schematic diagram from another perspective of the present invention; Figure 4This is a partial cross-sectional structural diagram of the present invention; Figure 5 This is a schematic cross-sectional view of the pilot valve in this invention; Figure 6 This is a partial enlarged cross-sectional structural diagram of the pilot valve in this invention; Figure 7 This is a partial cross-sectional enlarged structural schematic diagram of the small valve core and the pilot valve core in this invention.

[0016] Legend: 1. Hydraulic cylinder; 11. Piston; 12. Pusher shaft; 13. Left end push chamber; 14. Right end push chamber; 2. Rotary joint; 3. Oil tank; 31. Oil pump; 4. Valve island; 41. Oil inlet circuit; 42. Oil return circuit; 5. Main valve; 51. Main valve body; 511. Main valve inlet chamber; 512. Main valve return chamber; 52. Main valve core; 521. Main valve inlet ring chamber; 522. Main valve return ring chamber; 53. Main valve left chamber; 54. Main valve right chamber; 55. Left end supply chamber; 56. Right end supply chamber; 6. Pilot valve; 61. Pilot valve body; 611. Pilot valve inlet chamber; 612. Pilot valve return chamber; 62. 621. Valve core; 63. Pilot valve ring cavity; 64. Left reversing oil circuit; 65. Right reversing oil circuit; 66. Left end safety relief valve; 7. Cooler; 8. Pilot relief valve; 9. Speed ​​control valve; 10. Small valve core; 101. Left valve seat; 102. Right valve seat; 103. Small valve core limiting component; 104. Small valve core reversing oil inlet channel; 105. Small valve core reversing oil return channel; 106. Damping component; 107. Small valve core oil inlet chamber; 108. Small valve core oil return chamber; 109. Pilot valve oil inlet channel; 110. Pilot valve left end oil inlet / outlet port; 111. Pilot valve right end oil inlet / outlet port; 112. Pilot valve oil return port. Detailed Implementation

[0017] The following description, in conjunction with the accompanying drawings, further illustrates the pressure reversing device and control method for a pusher centrifuge according to the present invention.

[0018] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0019] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly; for example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can also mean a mechanical connection, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] See Figures 1-7 As shown, a pressure reversing device for a pusher centrifuge includes a hydraulic cylinder 1, a piston 11 disposed within the hydraulic cylinder 1, a pusher shaft 12 connected to the piston 11, and a rotary joint 2 connected to the hydraulic cylinder 1. The piston 11 forms a left-end pusher chamber 13 and a right-end pusher chamber 14 within the hydraulic cylinder 1. It is characterized by further including an oil tank 3, an oil pump 31 connected to the oil tank 3 via a pipeline, a valve island 4 connected to the oil pump 31 via a pipeline, an inlet oil passage 41 and a return oil passage 42 disposed on the valve island 4, a main valve 5 disposed on the valve island 4 and connected to the inlet oil passage 41 for controlling the oil supply to the left-end pusher chamber 13 or the right-end pusher chamber 14, and a pilot valve 6 disposed on the main valve 5 and connected to the inlet oil passage 41 for controlling the reversing of the main valve 5 and controlling the reversing of the piston 11. The rotary joint 2 is provided with oil passages to the left end propulsion chamber 13 and the right end propulsion chamber 14 respectively, and the oil passage interfaces are connected to the oil passage channels on the valve island 4 through pipelines respectively; The main valve 5 includes a main valve body 51 connected to the valve island 4 and communicating with the oil inlet passage 41 on the valve island 4, a main valve 5 chamber disposed in the main valve body 51, and a main valve core 52 slidably connected in the main valve 5 chamber for controlling the direction of the oil passage. The main valve 5 has a main valve left chamber 53 and a main valve right chamber 54 formed at both ends of the main valve core 52. The pilot valve 6 includes a pilot valve body 61 connected to the main valve body 51 and communicating with the oil inlet passage 41 on the valve island 4, a pilot valve 6 cavity disposed on the pilot valve body 61, a pilot valve core 62 slidably connected in the pilot valve body 61 for controlling the direction of movement of the main valve core 52, and a small valve core 10 slidably connected in the pilot valve core 62 for controlling the direction of movement of the pilot valve core 62. The reversing action of the small valve core 10 is used to switch the reversing action of the pilot valve core 62, the reversing action of the pilot valve core 62 is used to switch the reversing action of the main valve core 52, and the reversing action of the main valve core 52 is used to control the reversing action of the piston 11. It also includes a left valve seat 101 and a right valve seat 102 disposed in the pilot valve body 61, and a small valve core limiting member 103 connected to both ends of the pilot valve core 62 by threads. The small valve core limiting member 103 is provided with a channel communicating with the chamber of the pilot valve 6. The main valve body 51 and the pilot valve body 61 are provided with a left reversing oil passage 63 that communicates with the left chamber 53 of the main valve and a right reversing oil passage 64 that communicates with the right chamber 54 of the main valve. With the configuration of this invention, after the piston 11 moves to its position in the cylinder 1, the hydraulic system pressure rises rapidly because the reversing oil circuit is not switched and the oil circuit is blocked. The rapidly rising pressure is used to control the reversing of the main valve 5 and the pilot valve 6, thereby controlling the reversing of the piston 11. The reversing signal is generated by the increase in pressure in the hydraulic system after the piston 11 moves to its position, which can effectively ensure that the piston 11 moves to its position before switching, thus eliminating the problem of short push in the pusher centrifuge. The structure of piston 11 inside cylinder 1 is simplified. The main valve 5 is used to control the reversing oil circuit of piston 11. The main valve core 52 of the main valve 5 is controlled by the pilot valve 6. The movement of the pilot valve core 62 is controlled by the small valve core 10. The movement of the small valve core 10 is controlled by the pressure driving the connection state of the oil circuit of the left safety relief valve 65 or the right safety relief valve 66 at both ends.

[0021] In one embodiment, the main valve body 51 is provided with a left-end oil supply chamber 55 and a right-end oil supply chamber 56 that communicate with the main valve 5 chamber. The valve island 4 is provided with oil passages that communicate with the left-end oil supply chamber 55 and the right-end oil supply chamber 56 respectively. The oil passage that communicates with the left-end oil supply chamber 55 is connected to the left-end propulsion chamber 13 through a pipeline, and the oil passage that communicates with the right-end oil supply chamber 56 is connected to the right-end propulsion chamber 14 through a pipeline.

[0022] In one embodiment, the system further includes a main valve inlet chamber 511 disposed on the main valve body 51 and connected to the oil inlet passage 41 on the valve island 4, a main valve inlet ring chamber 521 disposed on the main valve core 52 and connected to the main valve inlet chamber 511, an oil return passage 42 disposed on the valve island 4, a main valve return passage 512 disposed on the main valve body 51 and connected to the oil return passage 42, and a main valve return ring chamber 522 disposed on both sides of the main valve inlet ring chamber 521 and connected to the main valve return passage 512. Hydraulic oil first enters the main valve inlet chamber 511 through the oil inlet passage 41 of valve island 4. By moving the main valve core 52, the main valve inlet ring chamber 521 is moved. When the main valve inlet ring chamber 521 moves, it connects the main valve inlet chamber 511 with the left end oil supply chamber 55 or the right end oil supply chamber 56 to form an oil supply passage, which supplies oil to the left end push chamber 13 or the right end push chamber 14 to push the piston 11 to reciprocate in the oil cylinder 1.

[0023] In one embodiment, a cooler 7 is also included, which is connected to the return oil line 42 via a pipeline and is connected to the oil tank 3 via a pipeline. The cooler 7 is used to cool the hydraulic oil after use and then return it to the oil tank 3.

[0024] In one embodiment, the system further includes a small valve core reversing oil inlet channel 104 and a small valve core reversing oil return channel 105 disposed on the pilot valve body 61, and a left-end safety relief valve 65 and a right-end safety relief valve 66 connected to the pilot valve 6 for controlling the opening and closing of the small valve core reversing oil inlet channel 104 and the small valve core reversing oil return channel 105. The small valve core reversing oil return channel 105 is connected to the pilot valve 6 chamber and the pilot valve return oil chamber 612. The small valve core reversing oil inlet channel 104 on the left side is connected to the left reversing oil passage 63, and the small valve core reversing oil inlet channel 104 on the right side is connected to the right reversing oil passage 64. When the system pressure exceeds the set value, the oil in the small valve core reversing oil inlet channel 104 pushes the left end safety relief valve 65 and the right end safety relief valve 66 to open, driving the oil into the pilot valve 6 chamber to push the small valve core 10 to reverse. When the small valve core 10 is squeezed, it squeezes the oil in the pilot valve 6 chamber on that side. The oil in the pilot valve 6 chamber flows through the small valve core 10 return oil channel to the pilot valve return oil chamber 612 and then returns through the return oil circuit 42. Damping elements 106 are installed in both the small valve core reversing return oil channel 105 and the small valve core reversing inlet oil channel 104. The damping elements 106 are provided with damping holes. The diameter of the damping hole on the damping element 106 in the small valve core reversing inlet oil channel 104 is larger than that on the damping hole on the damping element 106 in the small valve core reversing return oil channel 105. This allows most of the oil to enter the pilot valve 6 chamber after the small valve core reversing inlet oil channel 104 pushes open the left-end safety relief valve 65 and the right-end safety relief valve 66, thus pushing the small valve core 10 to move. A small portion of the oil flows through the damping hole on the damping element 106 in the small valve core reversing return oil channel 105 to the pilot valve return oil chamber 612 for return oil. By setting the left-end safety relief valve 65 and the right-end safety relief valve 66, when the oil pressure exceeds the left-end safety relief valve 65 or the right-end safety relief valve 66, the left-end safety relief valve 65 or the right-end safety relief valve 66 is opened, allowing oil to enter the pilot valve 6 chamber and push the small valve core 10 to move and switch the oil circuit, thereby switching the position of the pilot valve core 62. After the pilot valve core 62 is switched, the oil circuit is switched, driving the main valve 5 to reverse, thus realizing the oil circuit switching.

[0025] In one embodiment, it further includes a pilot valve inlet chamber 611 disposed on the pilot valve body 61 and communicating with the inlet oil passage 41, a pilot valve annular cavity 621 disposed on the pilot valve core 62 and communicating with the pilot valve inlet chamber 611, and a pilot valve return chamber 612 disposed on the pilot valve core 62 on both sides of the pilot valve annular cavity 621 and communicating with the return oil passage 42. When the pilot valve ring cavity 621 is connected to the pilot valve inlet cavity 611, it is used as an inlet ring cavity; when the pilot valve ring cavity 621 is connected to the pilot valve return cavity 612, it is used as a return ring cavity. It also includes a small valve core oil inlet chamber 107 disposed on the small valve core 10, a small valve core oil return chamber 108 disposed on the small valve core 10 at both sides of the small valve core oil inlet chamber 107, a pilot valve oil inlet channel 109 disposed on the pilot valve core 62 for connecting the pilot valve oil inlet chamber 611 and the small valve core oil inlet chamber 107, a pilot valve left end oil inlet / outlet hole 110 and a pilot valve right end oil inlet / outlet hole 111 disposed on the pilot valve core 62 and connected to the small valve core oil return chamber 108, and a pilot valve oil return hole 112 disposed on the pilot valve core 62 for connecting the small valve core oil return chamber 108 and the pilot valve oil return chamber 612; The pilot valve inlet chamber 611 is connected to the inlet oil passage 41 on the valve island 4. Part of the hydraulic oil delivered through the inlet oil passage 41 enters the main valve inlet chamber 511, and part of it enters the pilot valve inlet chamber 611. The pilot valve return oil chamber 612 is connected to the return oil circuit 42. During the return oil flow, the hydraulic oil flows back to the oil tank 3 through the pilot valve ring chamber 621, the pilot valve return oil chamber 612, the return oil circuit 42 and the pipeline.

[0026] In one embodiment, a pilot relief valve 8 is also included, which is connected to the valve island 4 and communicates with the oil inlet passage and the oil return passage. By setting the pilot relief valve 8, when an abnormal situation occurs and the system pressure reaches the set value for opening the pilot relief valve 8, the pilot relief valve 8 opens, and the pumped hydraulic oil returns to the oil tank 3 through the pilot relief valve 8, thus protecting the hydraulic system.

[0027] In one embodiment, a speed regulating valve 9 is also included, which connects the oil inlet 41 of the valve island 4 and the oil tank 3, and is used to control the amount of hydraulic oil entering the oil cylinder 1 to adjust the number of times the pushing centrifuge pushes the material. By setting the speed control valve 9, the amount of hydraulic oil input into the oil cylinder 1 can be reduced by opening the speed control valve 9, thereby adjusting the pushing speed of the oil cylinder 1 and extending the time required to complete one pushing stroke. This can then be used to adjust the number of times the centrifuge pushes within a set time.

[0028] The working process of this invention: First, start the oil pump 31. The oil pump 31 draws hydraulic oil from the oil tank 3 and supplies it to the oil inlet circuit 41 of the valve island 4. Part of the hydraulic oil in the oil inlet circuit 41 enters the main valve oil inlet chamber 511 and part of it enters the pilot valve oil inlet chamber 611. When the left end of the pilot valve core 62 is in contact with the left valve seat 101, the pilot valve inlet chamber 611 on the pilot valve core 62 is connected to the pilot valve ring chamber 621. The hydraulic oil enters the right chamber 54 of the main valve through the pilot valve inlet chamber 611, the pilot valve ring chamber 621 on the right side, and the right reversing oil passage 64, and then pushes the main valve core 52 to move to the left. After the main valve core 52 moves to the left until the left end of the main valve core 52 fits against the left side of the main valve 5 chamber, the main valve oil inlet ring chamber 521 on the main valve core 52 is connected to the left end oil supply chamber 55. After connection, the hydraulic oil is supplied to the left end push chamber 13 through the pipeline after passing through the main valve inlet ring chamber 521, the left end supply chamber 55, and the oil passage, thus pushing the piston 11 to move to the right. As the piston 11 moves to the right, it squeezes the hydraulic oil in the right end thrust chamber 14. The hydraulic oil in the right end thrust chamber 14 enters the return oil circuit 42 through the pipeline, oil inlet channel, right end oil supply chamber 56, and main valve 5 return ring chamber. After being cooled by the cooler 7 through the pipeline, it flows back to the oil tank 3. After piston 11 moves to the right end to the bottom, the hydraulic system is blocked. Under continuous oil supply, the system pressure rises. When the system pressure reaches the set pressure of 3MPa of the right end safety relief valve 66; When the right-end safety relief valve 66 on the pilot valve 6 is opened, the hydraulic oil enters the right side of the pilot valve 6 chamber through the pilot valve inlet chamber 611, the pilot valve ring chamber 621 on the right side, the small valve core reversing inlet channel 104, and the right-end safety relief valve 66. After entering the right side of the pilot valve 6 chamber, the hydraulic oil is pushed to the left by the channel on the small valve core limiting member 103 until it is in contact with the small valve core limiting member 103. During the leftward movement, the small valve core 10 squeezes the hydraulic oil in the left-side pilot valve 6 chamber, driving the hydraulic oil to return through the small valve core reversing return channel 105, the pilot valve return chamber 612, and the return oil circuit 42. At this time, the pilot valve inlet chamber 611, the pilot valve inlet channel 109, the small valve core inlet chamber 107, and the pilot valve left end inlet / outlet port 110 are connected, pushing the pilot valve core 62 to move to the right until the right end of the pilot valve core 62 is in contact with the right valve seat 102; during the process of the pilot valve core 62 moving to the right, the pilot valve right end inlet / outlet port 111, the small valve core return chamber 108, the pilot valve return port 112, the right reversing oil passage 64, the pilot valve ring chamber 621 on the right side, the pilot valve return chamber 612, and the return oil passage 42 are connected, and the hydraulic oil between the pilot valve core 62 and the right valve seat 102 is returned through the pilot valve right end inlet / outlet port 111, the small valve core return chamber 108, the pilot valve return port 112, the pilot valve return chamber 612, and the return oil passage 42; The pilot valve inlet chamber 611 on the pilot valve core 62 and the pilot valve ring chamber 621 on the left side are connected to the left reversing oil passage 63; After the hydraulic oil enters the left chamber 53 of the main valve through the pilot valve inlet chamber 611, the pilot valve ring chamber 621, and the left reversing oil passage 63, it pushes the main valve core 52 to move to the right. During the rightward movement, the main valve core 52 squeezes the hydraulic oil in the right chamber 54 of the main valve, causing the hydraulic oil to return through the right reversing oil passage 64, the pilot valve ring chamber 621, the pilot valve return oil chamber 612, and the return oil passage 42. After the main valve core 52 moves to the right until the right end of the main valve core 52 fits against the right side of the main valve chamber 5, the main valve inlet ring chamber 521 on the main valve core 52 is connected to the right end oil supply chamber 56. Hydraulic oil is supplied to the right-end push chamber 14 through the main valve inlet ring chamber 521, the right-end supply chamber 56, and the oil passage, and then pushes the piston 11 to move to the left to achieve reversal. After piston 11 moves to the left end bottom, the hydraulic system is blocked. Under continuous oil supply, the system pressure rises. When the system pressure rises to the set pressure of 3MPa of the left end safety relief valve 65; When the left-end safety relief valve 65 on the pilot valve 6 is opened, hydraulic oil enters the left side of the pilot valve 6 chamber through the pilot valve inlet chamber 611, the pilot valve annular chamber 621, the small valve core reversing inlet channel 104, and the left-end safety relief valve 65, pushing the small valve core 10 to move to the right until it is in contact with the small valve core limiting member 103; during the rightward movement, the small valve core 10 squeezes the hydraulic oil in the right-side pilot valve 6 chamber, driving the hydraulic oil to return through the small valve core reversing return channel 105, the pilot valve return chamber 612, and the return oil circuit 42. At this time, the pilot valve inlet chamber 611, the pilot valve inlet channel 109, the small valve core inlet chamber 107, and the right end inlet / outlet port 111 of the pilot valve are connected, pushing the pilot valve core 62 to move to the left until the left end of the pilot valve core 62 is in contact with the left valve seat 101; during the process of the pilot valve core 62 moving to the left, the left end inlet / outlet port 110 of the pilot valve, the small valve core return chamber 108, the pilot valve return port 112, the left reversing oil passage 63, the pilot valve ring chamber 621 on the left side, the pilot valve return chamber 612, and the return oil passage 42 are connected, and the hydraulic oil between the left valve seat 101 and the pilot valve core 62 returns under pressure through the left end inlet / outlet port 110 of the pilot valve, the small valve core return chamber 108, the pilot valve return port 112, the pilot valve return chamber 612, and the return oil passage 42; The pilot valve inlet chamber 611 on the pilot valve core 62 and the pilot valve ring chamber 621 on the right side are connected to the right reversing oil passage 64, which controls the main valve 5 to reverse again. After the main valve 5 reverses again, it controls the piston 11 to reverse again. During the leftward movement of the main valve 5, it squeezes the hydraulic oil in the left chamber 53 of the main valve, and drives the hydraulic oil to return through the left reversing oil passage 63, the pilot valve ring chamber 621, the pilot valve return oil chamber 612 and the return oil passage 42. If the oil pressure reaches the set 4MPa of the pilot relief valve 8 during operation, the pilot relief valve 8 will open, and the pumped hydraulic oil will return to the oil tank 3 after passing through the pilot relief valve 8. During the oil supply process, the pushing speed can be adjusted by opening the speed control valve 9 to adjust the amount of hydraulic oil in the oil cylinder 1, thereby adjusting the number of times the material is pushed within a set time.

[0029] The scope of protection of this invention is not limited to the above embodiments and their variations. Conventional modifications and substitutions made by those skilled in the art based on the content of these embodiments are all within the scope of protection of this invention.

Claims

1. A control method for a pressure reversing device of a pusher centrifuge, characterized in that: The control method is as follows: a. Start the oil pump. The oil pump draws hydraulic oil from the oil tank and supplies it to the valve island's oil inlet circuit. b. Part of the hydraulic oil in the oil inlet circuit enters the main valve inlet chamber, and part enters the pilot valve inlet chamber; c. When the left end of the pilot valve core is in contact with the left valve seat, the pilot valve inlet chamber on the pilot valve core is connected to the pilot valve annular chamber on the right side; d. After the hydraulic oil enters the right chamber of the main valve through the pilot valve inlet chamber, the pilot valve ring chamber, and the right reversing oil circuit, it pushes the main valve core to move to the left; e. After the main valve core moves to the left until the left end of the main valve core fits against the left side of the main valve chamber, the main valve inlet ring chamber on the main valve core is connected to the left end oil supply chamber; f. Hydraulic oil is supplied to the left-end push chamber through the main valve inlet ring chamber, the left-end supply chamber, and the oil passage, and then pushes the piston to move to the right. g. After the piston moves to the right and reaches the bottom of the right end, the hydraulic system is blocked. Under continuous oil supply, the system pressure rises. When the system pressure rises to the set pressure of the right-end safety relief valve; h. When the right-end safety relief valve on the pilot valve is opened, hydraulic oil enters the right side of the pilot valve chamber through the pilot valve inlet chamber, the pilot valve ring chamber, the small valve core reversing inlet channel, and the right-end safety relief valve, pushing the small valve core to move to the left until it is in contact with the small valve core limit piece; i. At this time, the pilot valve inlet chamber, pilot valve inlet channel, small valve core inlet chamber and pilot valve left end inlet / outlet port are connected, pushing the pilot valve core to move to the right until the right end of the pilot valve core is in contact with the right valve seat; during the process of the pilot valve core moving to the right, the pilot valve right end inlet / outlet port, small valve core return chamber, pilot valve return port, right reversing oil circuit, pilot valve ring chamber on the right side, pilot valve return chamber and return oil circuit are connected; j. The pilot valve inlet chamber on the pilot valve core and the pilot valve ring chamber on the left side are connected to the left reversing oil circuit; k. After the hydraulic oil enters the left chamber of the main valve through the pilot valve inlet chamber, the pilot valve ring chamber, and the left reversing oil circuit, it pushes the main valve core to move to the right; 1. After the main valve core moves to the right until the right end of the main valve core fits against the right side of the main valve chamber, the main valve inlet ring chamber on the main valve core is connected to the right end oil supply chamber; m. Hydraulic oil is supplied to the right-end push chamber through the main valve inlet ring chamber, the right-end supply chamber, and the oil passage, and then pushes the piston to move to the left to achieve reversal; n. After the piston moves to the bottom of the left end, the hydraulic system is blocked. Under continuous oil supply, the system pressure rises. When the system pressure rises to the set pressure of the safety relief valve at the left end; o. The left-end safety relief valve on the pilot valve opens, and the hydraulic oil enters the left side of the pilot valve chamber through the pilot valve inlet chamber, the pilot valve ring chamber, the small valve core reversing inlet channel, and the left-end safety relief valve, pushing the small valve core to move to the right until it is in contact with the small valve core limit piece; p. At this time, the pilot valve inlet chamber, pilot valve inlet channel, small valve core inlet chamber and right end inlet / outlet port of the pilot valve are connected, pushing the pilot valve core to move to the left until the left end of the pilot valve core is in contact with the left valve seat; during the process of the pilot valve core moving to the left, the left end inlet / outlet port of the pilot valve, the small valve core return chamber, the pilot valve return port, the left reversing oil circuit, the pilot valve annular cavity on the left side, the pilot valve return chamber and the return oil circuit are connected; q. The pilot valve inlet chamber on the pilot valve core and the pilot valve ring chamber on the right side are connected to the right reversing oil circuit, which controls the main valve to reverse again. After the main valve reverses again, it controls the piston to reverse again. r. During operation, if the oil pressure reaches the set pressure of the pilot relief valve, the pilot relief valve opens, and the pumped hydraulic oil returns to the oil tank after passing through the pilot relief valve.

2. The pressure reversing device for the pusher centrifuge in the control method according to claim 1, characterized in that: It includes a hydraulic cylinder, a piston installed inside the hydraulic cylinder, a pusher shaft connected to the piston, and a rotary joint connected to the hydraulic cylinder. The piston forms a left-end push chamber and a right-end push chamber inside the hydraulic cylinder. It also includes an oil tank, an oil pump connected to the oil tank via a pipeline, a valve island connected to the oil pump via a pipeline, an inlet oil passage and a return oil passage set on the valve island, a main valve set on the valve island and connected to the inlet oil passage for controlling the oil supply to the left or right end of the thrust chamber, and a pilot valve set on the main valve and connected to the inlet oil passage for controlling the main valve to switch direction and controlling the piston to switch direction.

3. The pressure reversing device for the pusher centrifuge in the control method according to claim 2, characterized in that: The main valve includes a main valve body connected to the valve island and communicating with the oil inlet passage of the valve island, a main valve cavity disposed in the main valve body, and a main valve core slidably connected in the main valve cavity for controlling the direction of the oil passage. The main valve forms a main valve left cavity and a main valve right cavity at both ends of the main valve core. The pilot valve includes a pilot valve body connected to the main valve body and communicating with the oil inlet passage of the valve island, a pilot valve cavity disposed on the pilot valve body, a pilot valve core slidably connected in the pilot valve body for controlling the direction of movement of the main valve core, and a small valve core slidably connected in the pilot valve core for controlling the direction of movement of the pilot valve core. It also includes a left valve seat and a right valve seat disposed in the pilot valve body, as well as small valve core limiting components connected to both ends of the pilot valve core; The main valve body and the pilot valve body are provided with a left reversing oil passage that communicates with the left chamber of the main valve and a right reversing oil passage that communicates with the right chamber of the main valve.

4. The pressure reversing device for the pusher centrifuge in the control method according to claim 3, characterized in that: The main valve body is provided with a left-end oil supply chamber and a right-end oil supply chamber that are connected to the main valve chamber. The valve island is provided with oil passages that are connected to the left-end oil supply chamber and the right-end oil supply chamber respectively. The oil passage connected to the left-end oil supply chamber is connected to the left-end propulsion chamber through a pipeline, and the oil passage connected to the right-end oil supply chamber is connected to the right-end propulsion chamber through a pipeline.

5. The pressure reversing device for the pusher centrifuge in the control method according to claim 4, characterized in that: It also includes a main valve inlet chamber located on the main valve body and connected to the inlet oil passage on the valve island, a main valve inlet ring chamber located on the main valve core and connected to the main valve inlet chamber, a return oil passage located on the valve island, a main valve return oil chamber located on the main valve body and connected to the return oil passage, and a main valve return oil ring chamber located on both sides of the main valve inlet ring chamber and connected to the main valve return oil chamber.

6. The pressure reversing device for the pusher centrifuge in the control method according to claim 5, characterized in that: It also includes a cooler connected to the return oil line via a pipeline, and the cooler is connected to the oil tank via a pipeline.

7. The pressure reversing device for the pusher centrifuge in the control method according to claim 6, characterized in that: It also includes a small valve core reversing oil inlet channel and a small valve core reversing oil return channel provided on the pilot valve body, as well as a left-end safety relief valve and a right-end safety relief valve connected to the pilot valve for controlling the opening and closing of the small valve core reversing oil inlet channel and the small valve core reversing oil return channel. The small valve core reversing oil return channel is connected to the pilot valve cavity, the small valve core reversing oil inlet channel on the left side is connected to the left reversing oil circuit, and the small valve core reversing oil inlet channel on the right side is connected to the right reversing oil circuit. Damping components are installed in both the small valve core reversing return oil channel and the small valve core reversing inlet oil channel. The damping components have damping holes, and the diameter of the damping hole on the damping component in the small valve core reversing inlet oil channel is larger than that of the damping hole on the damping component in the small valve core reversing return oil channel.

8. The pressure reversing device for the pusher centrifuge in the control method according to claim 7, characterized in that: It also includes a pilot valve inlet chamber disposed on the pilot valve body and connected to the inlet oil passage, a pilot valve annular cavity disposed on the pilot valve core and connected to the pilot valve inlet chamber, and a pilot valve return oil cavity disposed on both sides of the pilot valve annular cavity and connected to the return oil passage. It also includes a small valve core oil inlet chamber on the small valve core, small valve core return chambers on both sides of the small valve core oil inlet chamber on the small valve core, a pilot valve oil inlet channel on the pilot valve core for connecting the pilot valve oil inlet chamber and the small valve core oil inlet chamber, pilot valve left end oil inlet and outlet holes and pilot valve right end oil inlet and outlet holes on the pilot valve core for connecting the small valve core oil return chamber and the pilot valve return hole on the pilot valve core.

9. The pressure reversing device for the pusher centrifuge in the control method according to claim 8, characterized in that: It also includes a pilot relief valve connected to the valve island and communicating with the oil inlet and return channels.

10. The pressure reversing device for the pusher centrifuge in the control method according to claim 9, characterized in that: It also includes a speed control valve that connects the oil inlet circuit of the valve island and the oil tank, and is used to control the amount of hydraulic oil entering the oil cylinder to adjust the number of times the pusher centrifuge pushes the material.

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