Three-stage extrusion type coal slime filter pressing equipment and working method

Abstract

The invention provides three-stage extrusion type coal slime filter pressing equipment and a working method. The filter pressing equipment structurally comprises a thrust plate, a filter plate, filter cloth, a cross beam, a pressing plate, a pressing hydraulic system, a sealing unit, a feeding unit, a control unit and the like; columnar protruding structures arranged in an array mode are arranged on the outer surface of the filter plate, and each columnar protruding structure is in the structural form that a cone and a semicircle are combined. According to the requirements of the size and the dehydration rate of the filter plate, the columnar bulge structures are arranged on the surface of the filter plate by adopting a topological optimization method, so that the dehydration rate of the coal slime is improved, and the separation of a filter cake is facilitated; the pressing plate is of a sectional structure and is divided into three sections from left to right, and each section is connected with piston rods of the corresponding three hydraulic cylinders and corresponds to a three-stage extrusion working mode. And when the previous-stage extrusion pressure reaches 40% of the threshold pressure, the next-stage extrusion procedure is started. 40% of the extrusion threshold pressure can be set to ensure that the first two-stage extrusion is not finished when the third-stage extrusion process is started, so that the optimal extrusion mode of three-stage simultaneous extrusion is formed, the coal slime dehydration rate is increased to the greatest extent, and the filter pressing effect is improved. By adopting the three-stage extrusion mode, the dehydration process of each sub-area can be freely, flexibly and independently controlled, the toothpaste extrusion type collaborative filter pressing effect is achieved, the coal slime dehydration rate is higher, and the filter pressing effect is better.

Description

Technical Field

[0001] The invention provides a novel coal slime filter pressing device and a filter pressing method, belonging to the field of coal washing and processing equipment. Background Art

[0002] Coal slime dehydration is a key process in coal preparation operations in coal mines. Generally, filter press equipment is used to squeeze and dehydrate the coal slime to separate the solid and liquid of the coal slime, and the coal slime after filtration is recovered to achieve effective utilization of resources and energy conservation and environmental protection.

[0003] The patent "A filter press for mud water treatment that is easy to remove filter cakes and its filtration method" (2024104955693) applied by Zhejiang Huashi Pipeline Technology Co., Ltd. in 2024 proposes that a filter press block is installed on the inner side of the filter press body, and multiple filter press plates are slidably placed between one end of the filter press block and the filter press body. A diaphragm is installed inside the filter press plate, and a three-way air valve is fixed inside one side. The strip airbag is inflated and protrudes from the surface of the diaphragm body, thereby separating the filter cake separation net embedded in the surface of the diaphragm body from the diaphragm body and collecting the filter cake. This patented technology is suitable for small-scale filter pressing working conditions, and the dehydration rate is not high.

[0004] Guangdong Jinkaidi Filtration Equipment Co., Ltd. applied for the patent "Filter Press and Filter Press Method" (2012102895214) in 2012. The patent provides a three-stage filter press method. The first stage of filter press is that the material pump pumps the material into the filter press chamber through the material channel. Under the action of the material pump, the moisture in the material is discharged through the filter cloth and the filter screen; the second stage of filter press is to pass the high-pressure gas generated by the air compressor into the filter press chamber to further filter the material; the third stage of filter press is to drive the filter plate through the hydraulic device to filter, thereby realizing the three-stage filter press. This filter press method is powered by three different power sources, the system is relatively complex, and the extrusion force is small, and the filter press effect is not ideal.

[0005] The patent "Quick-opening Filter Press" (2006201284459) applied by Qin Haijiang in 2006 adopts a design structure that uses a movable thrust plate, one main and four auxiliary five oil cylinders to seal the filter unit, double-end feeding, and the filter plates in the filter unit are grouped and pulled apart three times to quickly unload. The five oil cylinders in this patent squeeze and filter at the same time, which easily causes incomplete squeezing of the coal slime, so the filter pressing effect is not ideal.

[0006] Qiu Lizhi applied for the patent "Multi-cylinder Synchronous Intelligent Filter Press" (201320045144X) in 2013. The clamping plate of the patent is driven by the oil cylinder. A rack is set on the filter press bracket, and a gear matching the rack is set on the clamping plate to ensure the synchronous movement of the upper and lower oil cylinders, thereby realizing the multi-cylinder synchronous filtration of the filter press. This filtration method is that multiple cylinders squeeze a single filter plate. The synchronization of each cylinder is affected by the gear rack mechanism, the output force of the oil cylinder is small, and the filtration effect is not ideal.

[0007] Quanzhou Zhuyou Environmental Protection Machinery Manufacturing Co., Ltd. applied for a patent in 2024, "An Automatic Locking Cylinder Filter Press and Filter Pressing Method" (2024107249593). The patent installs a filter press guide rail on the inner wall of the filter press body, and the hydraulic drive component of the filter press pushes the filter press plate to move along the length of the guide rail. The patent mainly designs a cylinder with an automatic locking function, and does not solve the problem of unsatisfactory existing filter pressing effect.

[0008] In 2014, Ruanshi Chemical (Changshu) Co., Ltd. applied for a patent for a multifunctional filter press (201420349208X). The filter plate in the patent is a concave structure, which can improve the filtration effect to a certain extent. However, the specific form and arrangement of the concave structure are unclear, and it cannot adapt to different filter plate structures and materials. In addition, the concave structure increases the difficulty of cleaning the filter cloth and discharging the filter cake.

[0009] Lianyungang Zhaoyu New Materials Industry Co., Ltd. applied for a patent for a "filter press" (2011202094448) in 2011. The front and rear sides of the filter plate body of the patent are respectively provided with inward grooves, and the surface of the grooves is provided with columnar protrusions. However, the specific form and arrangement of the columnar protrusions are unclear, and it is impossible to adapt to different filter plate structures and materials. In addition, the square equi-acute angle protrusion structure increases the difficulty of discharging the filter cake and is easy to damage the filter cloth.

[0010] In summary, existing filter press equipment generally adopts a multi-stage power source filter press method or a multi-cylinder synchronous filter press method, but this working method cannot solve the fundamental problem of poor coal slime dehydration effect, thereby reducing work efficiency and causing resource waste and environmental pollution. Summary of the invention

[0011] Aiming at the shortcomings of the existing filter press equipment structure and working method, the present invention provides a three-stage extrusion type coal slime filter press equipment and working method. The structure of the filter press equipment includes a thrust plate, a filter plate, a filter cloth, a crossbeam, a clamping plate, a clamping hydraulic system, a sealing unit, a feeding unit, a control unit, etc.

[0012] Furthermore, the thrust plate is located at the feed end of the filter press equipment, and is mainly used to prevent the filter plate from moving downward or being misplaced during the pressurization process, thereby ensuring the stability and sealing of the filter plate during the filtration process.

[0013] Furthermore, the filter plates are mounted on the crossbeams, and the filter plates are connected by connecting rods. The filter plates are wrapped with filter cloth on both sides to separate the filter chambers. The filter plates are surrounded by filter plate frames, and the outer surface of the filter plates is arranged with columnar protrusion structures arranged in an array, and the shape of each columnar protrusion structure is a combination of a cone and a semicircle. According to the filter plate size and dehydration rate requirements, the columnar protrusion structure is arranged on the filter plate surface by a topological optimization method, which is beneficial to both improving the dehydration rate of the coal slime and facilitating the detachment of the filter cake.

[0014] Furthermore, the filter cloth is a key component of the filter press equipment. The filter cloth is provided with pores, and the solid particles of coal slime in the suspension are separated from the liquid through its pore structure, thereby filtering out the liquid in the coal slime, while the solid particles are left on the surface of the filter cloth or inside the filter chamber to form a filter cake. The filter cloth is in close contact with the filter plate to ensure the sealing of the filter chamber, prevent liquid leakage, and maintain stability between the filter plates.

[0015] Furthermore, the crossbeam is an important structural component of the filter press equipment, which is mainly used to support and connect the filter plates and other components to maintain the stability of the overall structure of the filter press equipment and prevent abnormal displacement or deformation during operation.

[0016] Furthermore, the pressing plate is used to press the filter plate tightly to form a sealed filter cavity and effectively filter the moisture in the coal slime. The pressing plate is a segmented structure, which is divided into 3 sections from left to right, each section is connected to the corresponding 3 hydraulic cylinder piston rods, and corresponds to the three-stage extrusion working mode.

[0017] Furthermore, the hydraulic cylinders are evenly arranged in an array of 3 rows and 3 columns according to the surface area of ​​the clamping plate, with a total of 9 hydraulic cylinders. The 3 hydraulic cylinders in each column are of the same level and are connected to the corresponding clamping plate, with a total of three levels.

[0018] Furthermore, the clamping hydraulic system is composed of a hydraulic pump, a hydraulic cylinder, a one-way valve, an electro-hydraulic reversing valve, a proportional speed regulating valve, a safety valve, a proportional relief valve, an accumulator, an electromagnetic ball valve, a two-way hydraulic lock and an oil tank, and is used to control the filtration process of the filter press equipment, including three stages of pressurization, pressure maintenance and return. The filtration process can be repeated according to the actual working conditions and the filtration effect.

[0019] Furthermore, the hydraulic pump of the clamping hydraulic system is a one-way variable displacement piston pump, which is used to provide high-pressure oil to the system to drive the movement of the hydraulic cylinder.

[0020] Furthermore, the hydraulic cylinder of the clamping hydraulic system is connected to the clamping plate, and can push the clamping plate to perform filtering or retraction.

[0021] Furthermore, the one-way valve of the clamping hydraulic system is used to prevent the high-pressure oil from flowing back and damaging the hydraulic pump.

[0022] Furthermore, the electro-hydraulic reversing valve of the compacting hydraulic system receives instructions from the control unit to control the movement of the hydraulic cylinder to achieve coal slime filtration or return.

[0023] Furthermore, the proportional speed regulating valve of the clamping hydraulic system changes the throttle opening by changing the input voltage, thereby controlling the flow of the corresponding circuit, thereby achieving regulation of the movement speed of the hydraulic cylinder.

[0024] Furthermore, the safety valve of the compression hydraulic system is used to limit the maximum working pressure of the entire hydraulic system, thereby playing a role of safety protection.

[0025] Furthermore, the proportional relief valve of the clamping hydraulic system changes the relief pressure by changing the input voltage, thereby adjusting the oil pressure of the corresponding hydraulic branch.

[0026] Furthermore, the accumulator of the compacting hydraulic system is used to store high-pressure oil and maintain the pressure of the hydraulic cylinder during the pressure maintaining stage to improve the filter pressing effect.

[0027] Furthermore, the electromagnetic ball valve of the clamping hydraulic system is used to control the on-off of the hydraulic oil circuit supplied from the accumulator to the system.

[0028] Furthermore, the bidirectional hydraulic lock of the clamping hydraulic system is used to cut off the oil port of the hydraulic cylinder and the oil circuit of the pump source during the pressure maintaining stage, thereby achieving reliable pressure maintenance of the hydraulic cylinder.

[0029] Furthermore, the oil tank of the compacting hydraulic system is used to store oil for the hydraulic system of the filter press equipment, and has the functions of dissipating heat, separating bubbles in the oil, and precipitating impurities.

[0030] Furthermore, the sealing unit is used for sealing between the filter plates and between the filter plates and the frame to prevent water leakage during the filtration process, thereby improving the filtration efficiency and effect. The sealing unit adopts a super elastic frame made of chloroprene rubber, which has the characteristics of high strength, strong adaptability and excellent sealing performance.

[0031] Furthermore, the feeding unit is used to transport the material to the filter chamber evenly and stably for filter pressing operation.

[0032] Furthermore, the control unit includes a programmable logic controller (PLC), an oil pressure sensor, a flow sensor, a displacement sensor, a signal processing circuit, etc. The sensor detects the operating status of the system and transmits it to the PLC, which then performs data analysis and sends out command signals to control the actions of each actuator.

[0033] Furthermore, the working method of the three-stage extrusion type coal slime filter press equipment is as follows: Step 1, the pressurization stage, this stage includes two stages: rapid filling and three-stage extrusion.

[0034] The motor of the hydraulic system drives the hydraulic pump to start, the safety valve limits the maximum oil pressure of the system, and the proportional relief valve regulates the oil pressure of each branch. The electro-hydraulic reversing valves and electromagnetic ball valves at each level are controlled to work in the right position. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder, and drives the piston rod of the hydraulic cylinder to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve.

[0035] Increase the flow of the proportional speed control valve to the rapid filling threshold to achieve large-flow rapid filling of the hydraulic cylinder, so that the hydraulic cylinder piston rod drives the clamping plate to quickly reach the system set position, and the displacement sensor sends the detected clamping plate position signal to the control unit. The control unit issues a command to control the electro-hydraulic reversing valves at all levels to return to the middle position, and the hydraulic cylinders stop moving, and the rapid filling is completed; at the same time, the accumulator completes the oil pressure storage, the electromagnetic ball valve returns to the left position, and the system enters the three-stage extrusion operation stage.

[0036] The first-stage electro-hydraulic reversing valve is controlled to work in the right position, and the first-stage branch pressure is adjusted through the proportional relief valve. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder to drive the hydraulic cylinder piston rod to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve.

[0037] The first-stage proportional speed regulating valve is adjusted to reduce the flow of the first-stage hydraulic branch to the first-stage extrusion flow threshold and detected by the flow sensor; the first-stage proportional relief valve is adjusted to increase the oil pressure of the first-stage branch and detected by the oil pressure sensor, thereby driving the piston rod of the first-stage hydraulic cylinder to drive the clamping plate to extend at a low speed to perform the first-stage extrusion operation. When the first-stage extrusion pressure reaches 40% of the threshold pressure, the oil pressure sensor sends a signal to the control unit, and the control unit issues a command to start the second-stage extrusion process.

[0038] The second-stage electro-hydraulic reversing valve is controlled to work in the right position, and the second-stage branch pressure is adjusted through the proportional relief valve. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder to drive the hydraulic cylinder piston rod to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve.

[0039] The second-stage proportional speed regulating valve is adjusted to reduce the flow of the second-stage hydraulic branch to the second-stage extrusion flow threshold and detected by the flow sensor; the second-stage proportional relief valve is adjusted to increase the oil pressure of the second-stage branch and detected by the oil pressure sensor, thereby driving the second-stage hydraulic cylinder piston rod to drive the clamping plate to extend at a low speed to perform the second-stage extrusion operation. When the second-stage extrusion pressure reaches 40% of the threshold pressure, the oil pressure sensor sends a signal to the control unit, and the control unit issues a command to start the third-stage extrusion process.

[0040] The third-stage electro-hydraulic reversing valve is controlled to work in the right position, and the third-stage branch pressure is adjusted through the proportional relief valve. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder to drive the hydraulic cylinder piston rod to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve.

[0041] Adjust the third-stage proportional speed regulating valve to reduce the flow of the third-stage hydraulic branch to the third-stage extrusion flow threshold and detect it by the flow sensor; adjust the third-stage proportional relief valve to increase the oil pressure of the third-stage branch and detect it by the oil pressure sensor, and then drive the piston rod of the third-stage hydraulic cylinder to drive the clamping plate to extend at a low speed to perform the third-stage extrusion operation. Until the three-stage extrusion operation is completed. According to the actual working conditions and extrusion effect, the above three-stage extrusion operation can be repeated.

[0042] The setting of 40% of the extrusion threshold pressure for the inter-stage motion conversion of the hydraulic cylinder can be used to ensure that the first two stages of extrusion have not yet ended when the third stage of extrusion begins, thereby forming an optimal extrusion mode of three-stage simultaneous extrusion, maximizing the dehydration rate of the coal slime and improving the filter pressing effect. The threshold can be adjusted accordingly according to the actual working conditions and extrusion effect.

[0043] Step 2, pressure holding stage. After the pressurization stage is completed, the control unit issues a command, the hydraulic pump of the hydraulic system is turned off, and the electro-hydraulic reversing valve returns to the middle position, so the control oil pressure of the two-way hydraulic lock drops to 0. At this time, the two-way hydraulic lock is reversely cut off, so that the inlet and outlet oil ports of the hydraulic cylinder are reliably isolated from the pump source. Control the electromagnetic ball valve to work to the right position, and the high-pressure oil in the accumulator enters the rodless chamber of the hydraulic cylinder, thereby continuously providing oil pressure to the hydraulic cylinder during the pressure holding stage. This pressure holding stage lasts for about 5-10 minutes. When the pressure holding time is up, the control unit issues a command to control the electromagnetic ball valve to work to the left position, disconnect the oil circuit between the accumulator and the system, and the pressure holding ends. The pressure holding time can be adjusted accordingly according to the actual working conditions and extrusion effect.

[0044] Step 3, return stage. After the pressure holding stage is completed, the control unit issues a command, the motor of the hydraulic system drives the hydraulic pump to start again, the safety valve limits the maximum oil pressure of the system, the proportional relief valve regulates the output oil pressure of each level, the electro-hydraulic reversing valve works to the left position, the pressure oil enters the rod chamber of the hydraulic cylinder, and the piston rod drives the clamping plate to retract. When the clamping plate returns to the initial position, the displacement sensor sends a signal to the control unit, the control unit controls the hydraulic system to unload, and the hydraulic cylinder stops working.

[0045] The present invention adopts the above technical solution, and has the following technical effects compared with the prior art: 1. The three-stage extrusion method of the present invention can freely and flexibly control the dehydration process of each sub-region, so that the dehydration rate of the coal slime is higher and the filter pressing effect is better.

[0046] 2. The three-stage extrusion method of the present invention can achieve a "toothpaste squeezing" type of synergistic filtration effect by controlling the three-stage extrusion pressure. When the previous stage extrusion pressure reaches 40% of the threshold pressure, the next stage extrusion process is started. The setting of the extrusion threshold pressure of 40% can be used to ensure that the first two stages of extrusion have not ended when the third stage extrusion process starts, thereby forming an optimal extrusion mode of three-stage simultaneous extrusion, maximizing the dehydration rate of the coal slime and improving the filtration effect.

[0047] 3. In addition to the left-middle-right extrusion sequence of the present invention, the middle-left-right extrusion sequence can also be adopted to realize a filter pressing method that gradually releases from the center to the surroundings. The operation method is flexible and can effectively improve the filter pressing effect.

[0048] 4. The three-stage extrusion method of the present invention is adopted, and the outer surface of the filter plate is arranged with columnar protrusion structures arranged in an array, and the shape of each columnar protrusion structure is a combination of a cone and a semicircle. According to the filter plate size and dehydration rate requirements, the columnar protrusion structure is arranged on the filter plate surface by a topological optimization method, which is beneficial to improve the dehydration rate of the coal slime and facilitate the separation of the filter cake. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic diagram of a hydraulic circuit of a filter press in Embodiment 1 of the present invention; Figure 2 It is a schematic diagram of the overall structure of the filter press equipment in Example 1 of the present invention; Figure 3 is a schematic diagram of the structure of the pressing plate in Example 1 of the present invention; Figure 4 is a schematic diagram of the filter plate in Example 1 of the present invention; Figure 5 is a schematic diagram of a columnar protrusion structure in Example 1 of the present invention; In the figure, 1. oil tank 2. motor 3. hydraulic pump 4. safety valve 5. check valve 6. electro-hydraulic reversing valve 7. proportional relief valve 8. proportional speed regulating valve 9. flow sensor 10. two-way hydraulic lock 11. oil pressure sensor 12. electromagnetic ball valve 13. accumulator 14. hydraulic cylinder 15. displacement sensor 16. thrust plate 17. filter plate 18. filter cloth 19. crossbeam 20. clamping plate 21. clamping hydraulic system 170. filter plate frame 171. columnar protrusion structure DETAILED DESCRIPTION

[0050] Embodiment 1, as Figures 1 to 5 As shown, a three-stage extrusion type coal slime filter press equipment, the structure of the filter press equipment includes a thrust plate 16, a filter plate 17, a filter cloth 18, a crossbeam 19, a clamping plate 20, a clamping hydraulic system 21, a sealing unit, a feeding unit, a control unit, etc.

[0051] The thrust plate 16 is located at the feed end of the filter press equipment and is mainly used to prevent the filter plate 17 from moving downward or being misplaced during the pressurization process, thereby ensuring the stability and sealing of the filter plate 17 during the filter press process.

[0052] The filter plates 17 are mounted on the crossbeam 19, and the filter plates 17 are connected by connecting rods. The filter plates 17 are wrapped with filter cloth 18 on both sides to separate the filter chambers. The filter plates 17 are surrounded by filter plate frames 170, and the outer surface of the filter plates 17 is arranged with columnar protrusion structures 171 arranged in an array. The shape of each columnar protrusion structure 171 is a combination of a cone and a semicircle. According to the size of the filter plate 17 and the dehydration rate requirements, the columnar protrusion structure 171 is arranged on the surface of the filter plate 17 by a topological optimization method, which is beneficial to improving the dehydration rate of the coal slime and facilitating the detachment of the filter cake.

[0053] The filter cloth 18 is a key component of the filter press equipment. The filter cloth 18 is provided with pores. The solid particles of coal slime in the suspension are separated from the liquid through its pore structure, thereby filtering out the liquid in the coal slime, while the solid particles are left on the surface of the filter cloth 18 or inside the filter chamber to form a filter cake. The filter cloth 18 is in close contact with the filter plate 17 to ensure the sealing of the filter chamber, prevent liquid leakage, and maintain the stability between the filter plates 17.

[0054] The crossbeam 19 is an important structural component of the filter press equipment, and is mainly used to support and connect the filter plate 17 and other components to maintain the stability of the overall structure of the filter press equipment and prevent abnormal displacement or deformation during operation.

[0055] The pressing plate 20 is used to press the filter plate 17 tightly to form a sealed filter cavity and effectively filter the moisture in the coal slime. The pressing plate 20 is a segmented structure, which is divided into three sections from left to right, each section is connected to the corresponding three hydraulic cylinder piston rods, and corresponds to the three-stage extrusion working mode.

[0056] The hydraulic cylinders 14 are evenly arranged in an array of 3 rows and 3 columns according to the surface area of ​​the clamping plate 20, with a total of 9 hydraulic cylinders 14. The 3 hydraulic cylinders 14 in each column are of the same level and are connected to the corresponding clamping plate 20, with a total of three levels.

[0057] The clamping hydraulic system 21 is composed of a hydraulic pump 3, a hydraulic cylinder 14, a non-return valve 5, an electro-hydraulic reversing valve 6, a proportional speed regulating valve 8, a safety valve 4, a proportional relief valve 7, an accumulator 13, an electromagnetic ball valve 12, a two-way hydraulic lock 10 and an oil tank 1, and is used to control the filtration process of the filter press equipment, including three stages of pressurization, pressure maintenance and return. The filtration process can be repeated according to the actual working conditions and the filtration effect.

[0058] The hydraulic pump 3 of the clamping hydraulic system 21 is a one-way variable displacement piston pump, which is used to provide high-pressure oil to the system to drive the movement of the hydraulic cylinder 14 .

[0059] The hydraulic cylinder 14 of the clamping hydraulic system 21 is connected to the clamping plate 20 and can push the clamping plate 20 to perform filtering or retraction.

[0060] The one-way valve 5 of the clamping hydraulic system 21 is used to prevent the high-pressure oil from flowing back and damaging the hydraulic pump 3.

[0061] The electro-hydraulic reversing valve 6 of the compacting hydraulic system 21 receives the instruction from the control unit to control the movement of the hydraulic cylinder 14 to achieve the coal slime filtration or return.

[0062] The proportional speed regulating valve 8 of the clamping hydraulic system 21 changes the throttle opening by changing the input voltage, thereby controlling the flow of the corresponding circuit, thereby adjusting the movement speed of the hydraulic cylinder 14.

[0063] The safety valve 4 of the clamping hydraulic system 21 is used to limit the maximum working pressure of the entire hydraulic system, thus playing a role of safety protection.

[0064] The proportional relief valve 7 of the clamping hydraulic system 21 changes the relief pressure by changing the magnitude of the input voltage, thereby adjusting the oil pressure of the corresponding hydraulic branch.

[0065] The accumulator 13 of the compacting hydraulic system 21 is used to store high-pressure oil and maintain the pressure of the hydraulic cylinder 14 during the pressure maintaining stage to improve the filter pressing effect.

[0066] The electromagnetic ball valve 12 of the clamping hydraulic system 21 is used to control the on-off of the hydraulic oil circuit supplied from the accumulator 13 to the system.

[0067] The bidirectional hydraulic lock 10 of the clamping hydraulic system 21 is used to cut off the oil port of the hydraulic cylinder 14 and the oil path of the pump source during the pressure maintenance stage, thereby achieving reliable pressure maintenance of the hydraulic cylinder 14 .

[0068] The oil tank 1 of the compacting hydraulic system 21 is used to store oil for the hydraulic system of the filter press equipment, and has the functions of heat dissipation, separation of bubbles in the oil, precipitation of impurities, etc.

[0069] The sealing unit is used for sealing between the filter plates 17 and between the filter plates 17 and the frame to prevent water leakage during the filtration process, thereby improving the filtration efficiency and effect. The sealing unit adopts a super elastic frame made of chloroprene rubber, which has the characteristics of high strength, strong adaptability and excellent sealing performance.

[0070] The feeding unit is used to evenly and stably convey the material to the filter chamber for filter pressing operation.

[0071] The control unit includes a programmable logic controller (PLC), an oil pressure sensor 11, a flow sensor 9, a displacement sensor 15, a signal processing circuit, etc. The sensor detects the operating status of the system and transmits it to the PLC, which then performs data analysis and sends out command signals to control the actions of each actuator.

[0072] The working method of the three-stage extrusion type coal slime filter press equipment is as follows: Step 1, the pressurization stage, this stage includes two stages: rapid filling and three-stage extrusion.

[0073] The motor 2 of the hydraulic system 21 drives the hydraulic pump 3 to start, the safety valve 4 limits the maximum oil pressure of the system, and the proportional relief valve 7 regulates the oil pressure of each level of branches. The electro-hydraulic reversing valves 6 and the electromagnetic ball valve 12 of each level are controlled to work in the right position, and the high-pressure oil pumped out by the hydraulic pump 3 is input into the rodless chamber of the hydraulic cylinder 14 through the one-way valve 5, the electro-hydraulic reversing valve 6, the proportional speed regulating valve 8, the flow sensor 9, and the two-way hydraulic lock 10, and drives the piston rod of the hydraulic cylinder 14 to extend; the oil in the rod chamber returns to the oil tank 1 through the two-way hydraulic lock 10 and the electro-hydraulic reversing valve 6.

[0074] The flow rate of the proportional speed control valve 8 is increased to the rapid filling threshold to realize large-flow rapid filling of the hydraulic cylinder 14, so that the piston rod of the hydraulic cylinder 14 drives the clamping plate 20 to quickly reach the system set position, and the displacement sensor 15 sends the detected position signal of the clamping plate 20 to the control unit. The control unit issues a command to control the electro-hydraulic reversing valve 6 to return to the middle position, and each hydraulic cylinder 14 stops moving, and the rapid filling is completed; at the same time, the accumulator 13 completes the oil pressure storage, the electromagnetic ball valve 12 returns to the left position, and the system enters the three-stage extrusion operation stage.

[0075] The first-stage electro-hydraulic reversing valve 6a is controlled to work in the right position, and the first-stage branch pressure is adjusted through the proportional relief valve 7a. The high-pressure oil pumped out by the hydraulic pump 3a flows through the one-way valve 5a, the electro-hydraulic reversing valve 6a, the proportional speed regulating valve 8a, and the flow sensor 9a, and then passes through the three branches of the two-way hydraulic lock 10a, the two-way hydraulic lock 10b, and the two-way hydraulic lock 10c, and is respectively input into the rodless chamber of the hydraulic cylinder 14a, the hydraulic cylinder 14b, and the hydraulic cylinder 14c, and drives the piston rod to extend; the oil in the rod chamber returns to the oil tank 1 through the two-way hydraulic lock 10a, the two-way hydraulic lock 10b, the two-way hydraulic lock 10c, and the electro-hydraulic reversing valve 6a.

[0076] The first-stage proportional speed regulating valve 8a is adjusted to reduce the flow of the first-stage hydraulic branch to the first-stage extrusion flow threshold and detected by the flow sensor 9a; the first-stage proportional relief valve 7a is adjusted to increase the oil pressure of the first-stage branch and detected by the oil pressure sensor 11a, thereby driving the piston rods of the first-stage hydraulic cylinders 14a, 14b, and 14c to drive the clamping plate 20 to extend at a low speed to perform the first-stage extrusion operation. When the first-stage extrusion pressure reaches 40% of the threshold pressure, the oil pressure sensor 11a sends a signal to the control unit, and the control unit issues a command to start the second-stage extrusion process.

[0077] The second-stage electro-hydraulic reversing valve 6b is controlled to work in the right position, and the pressure of the second-stage branch is adjusted through the proportional relief valve 7b. The high-pressure oil pumped out by the hydraulic pump 3b flows through the one-way valve 5b, the electro-hydraulic reversing valve 6b, the proportional speed regulating valve 8b, and the flow sensor 9b, and then passes through the three branches of the two-way hydraulic lock 10d, the two-way hydraulic lock 10e, and the two-way hydraulic lock 10f, and is respectively input into the rodless chambers of the hydraulic cylinders 14d, 14e, and 14f, and drives the piston rod to extend; the oil in the rod chamber returns to the oil tank 1 through the two-way hydraulic lock 10d, the two-way hydraulic lock 10e, the two-way hydraulic lock 10f, and the electro-hydraulic reversing valve 6b.

[0078] The second-stage proportional speed regulating valve 8b is adjusted to reduce the flow of the second-stage hydraulic branch to the second-stage extrusion flow threshold and detected by the flow sensor 9b; the second-stage proportional relief valve 7b is adjusted to increase the oil pressure of the second-stage branch and detected by the oil pressure sensor 11b, thereby driving the piston rods of the second-stage hydraulic cylinders 14d, 14e, and 14f to drive the clamping plate 20 to extend at a low speed to perform the second-stage extrusion operation. When the second-stage extrusion pressure reaches 40% of the threshold pressure, the oil pressure sensor 11b sends a signal to the control unit, and the control unit issues an instruction to start the third-stage extrusion process.

[0079] The third-stage electro-hydraulic reversing valve 6c is controlled to work in the right position, and the pressure of the third-stage branch is adjusted through the proportional relief valve 7c. The high-pressure oil pumped out by the hydraulic pump 3c flows through the one-way valve 5c, the electro-hydraulic reversing valve 6c, the proportional speed regulating valve 8c, and the flow sensor 9c, and then passes through the three branches of the two-way hydraulic lock 10g, the two-way hydraulic lock 10h, and the two-way hydraulic lock 10i, and is respectively input into the rodless chamber of the hydraulic cylinder 14g, the hydraulic cylinder 14h, and the hydraulic cylinder 14i, and drives the piston rod to extend; the oil in the rod chamber returns to the oil tank 1 through the two-way hydraulic lock 10g, the two-way hydraulic lock 10h, the two-way hydraulic lock 10i, and the electro-hydraulic reversing valve 6c.

[0080] The third-stage proportional speed regulating valve 8c is adjusted to reduce the flow of the third-stage hydraulic branch to the third-stage extrusion flow threshold value and detected by the flow sensor 9c; the third-stage proportional relief valve 7c is adjusted to increase the oil pressure of the third-stage branch and detected by the oil pressure sensor 11c, thereby driving the piston rods of the third-stage hydraulic cylinders 14g, 14h and 14i to drive the clamping plate 20 to extend at a low speed to perform the third-stage extrusion operation. Until the three-stage extrusion operation is completed. According to the actual working conditions and extrusion effect, the above three-stage extrusion operation can be repeated.

[0081] The setting of 40% of the extrusion threshold pressure for the inter-stage motion conversion of the hydraulic cylinder 14 can be used to ensure that the first two stages of extrusion have not yet ended when the third stage of extrusion begins, thereby forming an optimal extrusion mode of three-stage simultaneous extrusion, maximizing the dehydration rate of the coal slime and improving the filter pressing effect. The threshold can be adjusted accordingly according to the actual working conditions and the extrusion effect.

[0082] Step 2, pressure-maintaining stage. After the pressurization stage is completed, the control unit issues a command, the hydraulic pump 3 of the hydraulic system is turned off, and the electro-hydraulic reversing valve 6 returns to the middle position, so that the control oil pressure of the two-way hydraulic lock 10 drops to 0. At this time, the two-way hydraulic lock 10 is reversely cut off, so that the inlet and outlet oil ports of the hydraulic cylinder 14 are reliably isolated from the pump source. The electromagnetic ball valve 12 is controlled to work to the right position, and the high-pressure oil in the accumulator 13 enters the rodless chamber of the hydraulic cylinder 14, thereby continuously providing oil pressure to the hydraulic cylinder 14 during the pressure-maintaining stage. This pressure-maintaining stage lasts for about 5-10 minutes. When the pressure-maintaining time is up, the control unit issues a command to control the electromagnetic ball valve 12 to work to the left position, disconnect the oil circuit between the accumulator 13 and the system, and the pressure-maintaining ends. The pressure-maintaining time can be adjusted accordingly according to the actual working conditions and extrusion effect.

[0083] Step 3, return stage. After the pressure holding stage is completed, the control unit issues a command, the motor 2 of the hydraulic system drives the hydraulic pump 3 to start again, the safety valve 4 limits the maximum oil pressure of the system, the proportional relief valve 7 regulates the output oil pressure of each level, the electro-hydraulic reversing valve 6 works to the left position, the pressure oil enters the rod chamber of the hydraulic cylinder 14, and the piston rod drives the clamping plate 20 to retract. When the clamping plate 20 returns to the initial position, the displacement sensor 15 sends a signal to the control unit, the control unit controls the hydraulic system to unload, and the hydraulic cylinder 14 stops working.

[0084] The above is an example of the best implementation of the present invention, and the parts not described in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical enlightenment of the present invention is also within the protection scope of the present invention.

Claims

1. A three-stage extrusion type coal slime filter press equipment, the structure of which includes a thrust plate, a filter plate, a filter cloth, a crossbeam, a clamping plate, a clamping hydraulic system, a sealing unit, a feeding unit, a control unit, etc.; characterized in that : The thrust plate is located at the feed end of the filter press equipment and is mainly used to prevent the filter plate from moving downward or dislocating during the pressurization process, thereby ensuring the stability and sealing of the filter plate during the filtration process; The filter plates are mounted on the crossbeams and connected by connecting rods. Filter cloths are wrapped on both sides of the filter plates to separate the filter chambers; The filter cloth is a key component of the filter press equipment. The filter cloth has pores, and the solid particles of coal slime in the suspension are separated from the liquid through its pore structure, thereby filtering out the liquid in the coal slime, while the solid particles are left on the surface of the filter cloth or inside the filter chamber to form a filter cake. The filter cloth is in close contact with the filter plate to ensure the sealing of the filter chamber, prevent liquid leakage, and maintain stability between the filter plates; The crossbeam is an important structural component of the filter press equipment, which is mainly used to support and connect the filter plates and other components to maintain the stability of the overall structure of the filter press equipment and prevent abnormal displacement or deformation during operation; The pressing plate is used to press the filter plate tightly to form a sealed filter cavity and effectively filter the moisture in the coal slime; The clamping hydraulic system is composed of a hydraulic pump, a hydraulic cylinder, a one-way valve, an electro-hydraulic reversing valve, a proportional speed regulating valve, a safety valve, a proportional relief valve, an accumulator, an electromagnetic ball valve, a two-way hydraulic lock and a fuel tank, and is used to control the filtration process of the filter press equipment; The hydraulic pump of the clamping hydraulic system is a one-way variable displacement plunger pump for providing high-pressure oil to the system to drive the movement of the hydraulic cylinder; The hydraulic cylinder of the clamping hydraulic system is connected to the clamping plate, which can push the clamping plate to perform filter pressing or retraction; The one-way valve of the clamping hydraulic system is used to prevent the high-pressure oil from flowing back and damaging the hydraulic pump; The electro-hydraulic reversing valve of the compacting hydraulic system receives the command from the control unit to control the movement of the hydraulic cylinder to achieve coal slime filtration or return; The proportional speed regulating valve of the clamping hydraulic system changes the throttle opening by changing the input voltage, thereby controlling the flow of the corresponding circuit, thereby achieving control of the movement speed of the hydraulic cylinder; The safety valve of the clamping hydraulic system is used to limit the maximum working pressure of the entire hydraulic system and plays a role in safety protection; The proportional relief valve of the clamping hydraulic system changes the relief pressure by changing the input voltage, thereby adjusting the oil pressure of the corresponding hydraulic branch; The accumulator of the compacting hydraulic system is used to store high-pressure oil and maintain the pressure of the hydraulic cylinder during the pressure-maintaining stage to improve the filter pressing effect; The electromagnetic ball valve of the clamping hydraulic system is used to control the on-off of the hydraulic oil circuit delivered from the accumulator to the system; The bidirectional hydraulic lock of the clamping hydraulic system is used to cut off the oil port of the hydraulic cylinder and the oil circuit of the pump source during the pressure maintenance stage, thereby achieving reliable pressure maintenance of the hydraulic cylinder; The oil tank of the compacting hydraulic system is used to store oil for the hydraulic system of the filter press equipment, and has the functions of heat dissipation, separation of bubbles in the oil, precipitation of impurities, etc. The sealing unit is used for sealing between the filter plates and between the filter plates and the frame to prevent water leakage during the filtration process, thereby improving the filtration efficiency and effect; The feeding unit is used to evenly and stably transport the material to the filter chamber for filter pressing operation; The control unit includes a programmable logic controller (PLC), an oil pressure sensor, a flow sensor, a displacement sensor, a signal processing circuit, etc. Various types of sensors detect the operating status of the system and transmit it to the PLC, which then performs status analysis and sends out command signals to control the actions of each actuator.

2. The structure according to claim 1, characterized in that The filter plate is surrounded by a filter plate frame, and the outer surface of the filter plate is arranged with columnar protrusion structures arranged in an array, and the shape of each columnar protrusion structure is a combination of a cone and a semicircle. According to the filter plate size and dehydration rate requirements, the columnar protrusion structure is arranged on the filter plate surface using the topological optimization method, which is beneficial to improving the dehydration rate of coal slime and facilitating the detachment of filter cake.

3. The structure according to claim 1, characterized in that The clamping plate is a segmented structure, which is divided into three sections from left to right. Each section is connected with the corresponding three hydraulic cylinder piston rods and corresponds to the three-stage extrusion working mode.

4. The structure according to claim 1, characterized in that The hydraulic cylinders of the clamping hydraulic system are evenly arranged in an array of 3 rows and 3 columns according to the surface area of ​​the clamping plate, with a total of 9 hydraulic cylinders. The 3 hydraulic cylinders in each column are of the same level and are connected to the corresponding clamping plate, with a total of three levels.

5. The structure according to claim 1, characterized in that The sealing unit adopts a super elastic frame made of neoprene, which has high strength, strong adaptability and excellent sealing performance.

6. A working method of the three-stage extrusion type coal slime filter press equipment as claimed in claim 1 is as follows: Step 1, the pressurization stage, which includes two stages: rapid filling and three-stage extrusion; The motor of the hydraulic system drives the hydraulic pump to start, the safety valve limits the maximum oil pressure of the system, and the proportional relief valve regulates the oil pressure of each branch. The electro-hydraulic reversing valves and electromagnetic ball valves at each level are controlled to work in the right position. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder, and drives the piston rod of the hydraulic cylinder to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve; Increase the flow rate of the proportional speed regulating valve to the fast filling threshold to achieve large-flow fast filling of the hydraulic cylinder, so that the piston rod of the hydraulic cylinder drives the clamping plate to quickly reach the system set position. The displacement sensor sends the detected clamping plate position signal to the control unit, and the control unit issues a command to control the electro-hydraulic reversing valve to return to the middle position, and each hydraulic cylinder stops moving, and the fast filling is completed; at the same time, the accumulator completes the oil pressure storage, the electromagnetic ball valve returns to the left position, and the system enters the three-stage extrusion operation stage; The first-stage electro-hydraulic reversing valve is controlled to work in the right position, and the first-stage branch pressure is adjusted through the proportional relief valve. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder to drive the hydraulic cylinder piston rod to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve; Adjust the first-stage proportional speed regulating valve to reduce the flow of the first-stage hydraulic branch to the first-stage extrusion flow threshold and detect it by the flow sensor; adjust the first-stage proportional relief valve to increase the oil pressure of the first-stage branch and detect it by the oil pressure sensor, thereby driving the piston rod of the first-stage hydraulic cylinder to drive the clamping plate to extend at a low speed to perform the first-stage extrusion operation. When the first-stage extrusion pressure reaches 40% of the threshold pressure, the oil pressure sensor sends a signal to the control unit, and the control unit issues a command to start the second-stage extrusion process; The second-stage electro-hydraulic reversing valve is controlled to work in the right position, and the second-stage branch pressure is adjusted through the proportional relief valve. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder to drive the hydraulic cylinder piston rod to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve; Adjust the second-stage proportional speed regulating valve to reduce the flow of the second-stage hydraulic branch to the second-stage extrusion flow threshold and detect it by the flow sensor; adjust the second-stage proportional relief valve to increase the oil pressure of the second-stage branch and detect it by the oil pressure sensor, thereby driving the second-stage hydraulic cylinder piston rod to drive the clamping plate to extend at a low speed to perform the second-stage extrusion operation. When the second-stage extrusion pressure reaches 40% of the threshold pressure, the oil pressure sensor sends a signal to the control unit, and the control unit issues a command to start the third-stage extrusion process; The third-stage electro-hydraulic reversing valve is controlled to work in the right position, and the third-stage branch pressure is adjusted through the proportional relief valve. The high-pressure oil pumped out by the hydraulic pump passes through the one-way valve, electro-hydraulic reversing valve, proportional speed regulating valve, flow sensor, and two-way hydraulic lock, and enters the rodless chamber of the hydraulic cylinder to drive the hydraulic cylinder piston rod to extend; the oil in the rod chamber returns to the oil tank through the two-way hydraulic lock and electro-hydraulic reversing valve; Adjust the third-stage proportional speed regulating valve to reduce the flow of the third-stage hydraulic branch to the third-stage extrusion flow threshold and detect it by the flow sensor; adjust the third-stage proportional relief valve to increase the oil pressure of the third-stage branch and detect it by the oil pressure sensor, thereby driving the piston rod of the third-stage hydraulic cylinder to drive the clamping plate to extend at a low speed to perform the third-stage extrusion operation. Until all three-stage extrusion operations are completed. According to the actual working conditions and extrusion effects, the above three-stage extrusion operations can be repeated; Step 2, pressure holding stage. After the pressurization stage is completed, the control unit issues a command, the hydraulic pump of the hydraulic system is turned off, and the electro-hydraulic reversing valve returns to the middle position. Therefore, the control oil pressure of the two-way hydraulic lock drops to 0. At this time, the two-way hydraulic lock is reversely cut off, so that the inlet and outlet oil ports of the hydraulic cylinder are reliably isolated from the pump source. Control the solenoid ball valve to work to the right position, and the high-pressure oil in the accumulator enters the rodless chamber of the hydraulic cylinder, thereby continuously providing oil pressure to the hydraulic cylinder during the pressure holding stage. This pressure holding stage lasts for about 5-10 minutes. When the pressure holding time is up, the control unit issues a command to control the solenoid ball valve to work to the left position, disconnect the oil circuit between the accumulator and the system, and the pressure holding ends. The pressure holding time can be adjusted accordingly according to the actual working conditions and extrusion effect; Step 3, return stage. After the pressure holding stage is completed, the control unit issues a command, the motor of the hydraulic system drives the hydraulic pump to start again, the safety valve limits the maximum oil pressure of the system, the proportional relief valve regulates the output oil pressure of each level, the electro-hydraulic reversing valve works to the left position, the pressure oil enters the rod chamber of the hydraulic cylinder, and the piston rod drives the clamping plate to retract. When the clamping plate returns to the initial position, the displacement sensor sends a signal to the control unit, the control unit controls the hydraulic system to unload, and the hydraulic cylinder stops working.

7. The working method according to claim 6, characterized in that: The setting of the extrusion threshold pressure of 40% for the inter-stage motion conversion of the hydraulic cylinder can be used to ensure that the first two stages of extrusion have not yet ended when the third stage of extrusion begins, thereby forming an optimal extrusion mode of three-stage simultaneous extrusion, maximizing the dehydration rate of the coal slime and improving the filter pressing effect. The threshold can be adjusted accordingly according to the actual working conditions and the extrusion effect.

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