Roller press hydraulic system capable of improving safety performance

Abstract

A roller press hydraulic system capable of improving safety performance comprises an oil tank, two electromagnetic directional valves and two sets of energy accumulators, an oil outlet pipeline of the oil tank is connected with oil inlets of the two electromagnetic directional valves, and an oil return pipeline of the oil tank is connected with oil return ports of the two electromagnetic directional valves. A working oil port of one electromagnetic reversing valve is communicated with a driving side oil cylinder through a driving side pipeline, a working oil port of the other electromagnetic reversing valve is communicated with a non-driving side oil cylinder through a non-driving side pipeline, and the driving side pipeline and the non-driving side pipeline are each connected with a set of energy accumulators. The same group of energy accumulators comprises a working energy accumulator in a normally-open state and two safety energy accumulators in a normally-closed state, and when the pressure value of the pressure sensor reaches a threshold value, the electromagnetic unloading valve and the two safety energy accumulators on the corresponding pipeline are all switched to be in an open state; therefore, hydraulic oil in the pipeline can flow into the two safety energy accumulators and can flow back to the oil tank through the unloading pipeline, the oil pressure is rapidly reduced, and rapid unloading is achieved.

Description

Technical Field

[0001] The invention relates to the field of hydraulic systems of roller presses, and in particular to a hydraulic system of a roller press with improved safety performance. Background Art

[0002] Roller mills are widely used in industries such as building materials, mining, and metallurgy. When the material passes between the fixed roller and the movable roller of the roller mill, the material is crushed by the extrusion force between the two rollers. Due to factors such as material segregation, there will be roller gap deviation on the drive side and the non-drive side when the material enters between the two rollers; the material processed by the roller mill is a mixed material, and it is easy to mix in non-extrudable substances, such as iron blocks. When these substances enter between the two rollers, it will cause iron overload; due to the harsh working environment, newly generated and newly immersed pollutants will cause hydraulic system valve jamming, excessive wear of hydraulic components and other faults, which will lead to the hydraulic system not maintaining pressure, frequent pressurization of the hydraulic pump, and heating of the hydraulic system. The above problems will affect the stable operation of the roller mill and reduce production efficiency. Iron overload can easily cause damage to the key components of the roller mill such as the roller surface and bearings, which will not only affect the normal production and operation of the roller mill, but also cause great economic losses. Therefore, it is necessary to improve the safety performance of the roller press. Summary of the invention

[0003] The purpose of the present invention is to provide a roller press hydraulic system with improved safety performance, so as to achieve constant pressure extrusion of materials and to rapidly reduce the oil pressure when the oil pressure is too high, thereby achieving rapid unloading.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a roller press hydraulic system with improved safety performance, which is used to simultaneously supply oil to the driving side cylinder and the non-driving side cylinder of the roller press, including an oil tank, two electromagnetic reversing valves and two groups of accumulators, the oil outlet pipeline of the oil tank is respectively connected to the oil inlet ports of the two electromagnetic reversing valves, the oil return pipeline of the oil tank is respectively connected to the oil return ports of the two electromagnetic reversing valves, the working oil port of one electromagnetic reversing valve is connected to the driving side cylinder through the driving side pipeline, the working oil port of the other electromagnetic reversing valve is connected to the non-driving side cylinder through the non-driving side pipeline, the driving side pipeline and the non-driving side pipeline are connected A group of accumulators are respectively connected to the roads, and the same group of accumulators includes a working accumulator in a normally open state and two safety accumulators in a normally closed state. A throttle valve and two one-way valves are arranged between the three accumulators and the corresponding driving side pipelines or non-driving side pipelines. One end of the throttle valve is connected to the pipeline, and the other end of the throttle valve is respectively connected to the three accumulators. The inlet of the one-way valve is connected to the pipeline, and the outlet of the one-way valve is respectively connected to the three accumulators, so that the hydraulic oil in the pipeline can flow into the working accumulator through the throttle valve and the two one-way valves, and the hydraulic oil in the working accumulator can flow into the pipeline through the throttle valve; The driving side pipeline and the non-driving side pipeline are respectively connected to the side close to the cylinder with pressure sensors, and the driving side pipeline and the non-driving side pipeline are respectively connected to the two branch pipelines of the unloading pipeline, and the two branch pipelines of the unloading pipeline are respectively connected to electromagnetic unloading valves. When the pressure value of any pressure sensor reaches the threshold value, the electromagnetic unloading valve and the two safety accumulators on the corresponding pipeline are switched to the open state, so that the hydraulic oil in the pipeline can flow into the two safety accumulators and flow back to the oil tank through the unloading pipeline.

[0005] Preferably, the working oil port of the electromagnetic reversing valve is connected to an electromagnetic unloading valve, a safety valve is connected between the oil inlet and oil return port of the electromagnetic reversing valve, and two branch pipelines of the unloading pipeline are respectively connected to the driving side pipeline and the non-driving side pipeline with safety valves.

[0006] Preferably, the inner cavity of the oil tank is divided into a clean side and an oil return side. The inner cavity of the clean side is connected to the oil outlet pipeline, and the inner cavity of the oil return side is connected to the oil return pipeline. A circulation pipeline connecting the clean side and the oil return side is provided outside the oil tank. A circulation pump, a circulation filter and a cooler are connected to the circulation pipeline to filter and cool the hydraulic oil on the oil return side before sending it to the clean side.

[0007] Preferably, the oil tank is provided with a thermometer, and the clean side inner cavity and the oil return side inner cavity are respectively provided with heaters.

[0008] According to the above technical solution, the beneficial effects of the present invention are: 1. The accumulator group of the present invention includes a working accumulator and two safety accumulators. When a large object enters between the two rollers of the roller press, causing the roller gap to become larger, so that the inner cavity of the oil cylinder shrinks with the movement of the piston, the hydraulic oil in the oil cylinder can quickly flow into the working accumulator through the throttle valve and two one-way valves, thereby reducing the oil pressure and expanding the roller gap; and when the material is too small, resulting in insufficient pressure between the two rollers and the roller gap needs to be reduced, the hydraulic oil in the working accumulator can flow into the pipeline through the throttle valve at an appropriate speed and then into the oil cylinder, thereby increasing the oil pressure and reducing the roller gap. Therefore, the present invention can automatically adjust the roller gap of the roller press to adapt to the size of the material, ensure that the extrusion force of the roller press is relatively stable, thereby achieving constant pressure extrusion of materials, and effectively improving the working efficiency and extrusion effect of the roller press.

[0009] 2. When the material entering between the two rollers of the roller press is too large, causing the piston rod of the oil cylinder to move significantly in a short time, resulting in the rapid shrinkage of the inner cavity of the oil cylinder and the sharp increase in the oil pressure, the present invention can promptly detect through the pressure sensor that the oil pressure in the pipeline exceeds the normal working pressure range, and can promptly switch the electromagnetic unloading valve and the two safety accumulators to the open state according to the monitoring signal of the pressure sensor. On the one hand, the hydraulic oil in the oil cylinder and the pipeline can directly flow back to the oil tank through the unloading pipeline, and on the other hand, it can quickly flow into the two safety accumulators through the one-way valve. Through the cooperation of these two aspects, the oil pressure can be quickly reduced to achieve rapid unloading, so that the main oil cylinder can quickly retreat under the action of load, so that the roller gap can be rapidly expanded to avoid excessive impact pressure peak, so as to eliminate overload impact and allow excessive abnormal materials to pass quickly, which greatly improves the iron overload protection capability of the roller press, effectively prolongs the service life of key components such as roller surface and bearings, and improves safety performance.

[0010] 3. The inner cavity of the oil tank of the present invention is divided into a clean side and an oil return side and connected by a circulating pipeline. The hydraulic oil on the oil return side can be filtered and cooled before being sent to the clean side. It has an oil self-purification function, effectively improves the cleanliness of the oil, reduces the wear of key components such as hydraulic system pumps and valves, and improves the stability and reliability of the hydraulic system of the roller press. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the hydraulic system of the present invention.

[0012] Markings in the figure: 1. Oil tank, 2. Oil suction filter, 3. Main hydraulic pump, 4. High-pressure filter, 5. Solenoid reversing valve, 6. Solenoid unloading valve, 7. Driving side pipeline, 8. Non-driving side pipeline, 9. Unloading pipeline, 10. Driving side cylinder, 11. Non-driving side cylinder, 12. Safety valve, 13. Pressure sensor, 14. Working accumulator, 15. Safety accumulator, 16. Throttle valve, 17. Check valve, 18. Thermometer, 19. Heater, 20. Circulation pipeline, 21. Circulation pump, 22. Circulation filter, 23. Cooler. DETAILED DESCRIPTION

[0013] With reference to the accompanying drawings, the specific implementation is as follows: like Figure 1As shown, a roller press hydraulic system with improved safety performance is used for simultaneously supplying oil to the driving side cylinder 10 and the non-driving side cylinder 11 of the roller press, comprising an oil tank 1, two electromagnetic reversing valves 5 and two groups of accumulators, the oil outlet pipeline of the oil tank 1 is respectively connected to the oil inlets of the two electromagnetic reversing valves 5, the oil return pipeline of the oil tank 1 is respectively connected to the oil return ports of the two electromagnetic reversing valves 5, the working oil port of one electromagnetic reversing valve 5 is connected to the driving side cylinder 10 through the driving side pipeline 7, the working oil port of the other electromagnetic reversing valve 5 is connected to the non-driving side cylinder 11 through the non-driving side pipeline 8, the working oil port of the electromagnetic reversing valve 5 is also connected to the electromagnetic unloading valve 6, and a safety valve (not shown in the figure) is connected between the oil inlet and the oil return port of the electromagnetic reversing valve 5, and the electromagnetic unloading valve 6 and the safety valve can provide safety protection when the electromagnetic reversing valve 5 fails.

[0014] A group of accumulators are respectively connected to the driving side pipeline 7 and the non-driving side pipeline 8. The same group of accumulators includes a working accumulator 14 in a normally open state and two safety accumulators 15 in a normally closed state. A throttle valve 16 and two one-way valves 17 are provided between the three accumulators and the corresponding driving side pipeline 7 or non-driving side pipeline 8. One end of the throttle valve 16 is connected to the pipeline, and the other end of the throttle valve 16 is respectively connected to the three accumulators. The inlet of the one-way valve 17 is connected to the pipeline, and the outlet of the one-way valve 17 is respectively connected to the three accumulators, so that the hydraulic oil in the pipeline can flow into the working accumulator 14 through the throttle valve 16 and the two one-way valves 17, and the hydraulic oil in the working accumulator 14 can flow into the pipeline through the throttle valve 16.

[0015] Through the above structure, the hydraulic system has the function of independent control of the driving side and the non-driving side and the correction function. During the operation of the roller press, when the roller deviation exceeds the set value, the side with the larger roller gap is pressurized, and the side with the smaller roller gap is appropriately depressurized. When the roller deviation returns to normal, the correction ends. Through the roller gap correction function, the roller gap deviation on the driving side and the non-driving side is kept within a certain range, thereby improving the operating efficiency of the roller press.

[0016] Driving side pressurization: the main hydraulic pump 3 is started, and the oil flows into the two electromagnetic reversing valves 5 through the oil suction filter 2 and the high-pressure filter 4. The electromagnetic reversing valve 5 of the driving side pipeline 7 is switched to connect the oil inlet with the working port, and the oil finally reaches the driving side cylinder 10 through the electromagnetic unloading valve 6 and three accumulators.

[0017] Non-driving side pressurization: the main hydraulic pump 3 is started, and the oil flows into the two electromagnetic reversing valves 5 through the oil suction filter 2 and the high-pressure filter 4. The electromagnetic reversing valve 5 of the non-driving side pipeline 8 is switched to connect the oil inlet with the working port, and the oil finally reaches the non-driving side cylinder 11 through the electromagnetic unloading valve 6 and three accumulators.

[0018] Driving side unloading: The oil in the driving side cylinder 10 flows into the electromagnetic reversing valve 5 through three accumulators and the electromagnetic unloading valve 6. The electromagnetic reversing valve 5 is switched so that the oil outlet is connected to the working port, and the oil flows back to the oil tank 1.

[0019] Unloading on the non-driving side: The oil in the non-driving side cylinder 11 flows into the electromagnetic reversing valve 5 through three accumulators and the electromagnetic unloading valve 6. The electromagnetic reversing valve 5 is switched so that the oil outlet is connected to the working port, and the oil flows back to the oil tank 1.

[0020] During the operation of the roller press, the oil pressure fluctuation caused by the change of material conditions is absorbed by the working accumulator 14. The working accumulator 14 and the oil cylinder together constitute a hydraulic spring with a certain rigidity. During the normal operation of the roller press, as the roller gap fluctuates, the oil flows back and forth between the working accumulator 14 and the oil cylinder uninterruptedly. A one-way valve 17 and a throttle valve 16 are designed between the working accumulator 14 and the oil cylinder. When the roller gap becomes larger and the oil pressure in the oil cylinder increases, the oil in the oil cylinder enters the working accumulator 14 at a faster speed through the one-way valve 17 and the throttle valve 16, avoiding overpressure of the hydraulic system and ensuring the safety of the hydraulic system and the roller press equipment; when the roller gap becomes smaller and the oil pressure in the oil cylinder decreases, the oil in the working accumulator 14 is replenished into the oil cylinder at a relatively slow speed through the throttle valve 16, thereby ensuring the relative stability of the operation of the hydraulic system and the roller press equipment. The one-way valve 17 of this embodiment adopts a two-way plug-in structure. Compared with the traditional one-way valve, it has the characteristics of large flow capacity, fast response speed, small flow resistance, etc., and avoids heating of the hydraulic system.

[0021] like Figure 1 As shown, the driving side pipeline 7 and the non-driving side pipeline 8 are respectively connected to the side close to the cylinder with a pressure sensor 13, the driving side pipeline 7 and the non-driving side pipeline 8 are respectively connected to the two branch pipelines of the unloading pipeline 9, the two branch pipelines of the unloading pipeline 9 are respectively connected to the electromagnetic unloading valve 6, and the two branch pipelines of the unloading pipeline 9 are respectively connected to the driving side pipeline 7 and the non-driving side pipeline 8 with a safety valve 12.

[0022] When the pressure value of any pressure sensor 13 reaches the threshold value, the electromagnetic unloading valve 6 and the two safety accumulators 15 on the corresponding pipeline are switched to the open state, so that the hydraulic oil in the pipeline can flow into the two safety accumulators 15 and flow back to the oil tank 1 through the unloading pipeline 9.

[0023] The materials processed by the roller press are mixed materials. During the production, transportation or storage process, some difficult-to-compress materials, such as iron blocks, may be mixed in. These abnormal materials enter the gap between the rollers and cause a sharp increase in pressure when passing through the extrusion rollers. When the pressure rises sharply and exceeds the normal working pressure range and cannot be unloaded normally, the hydraulic and electronic controls automatically start the load limit protection function. Specifically, in addition to the working accumulator 14 used to absorb pulsation during normal operation, two safety accumulators 15 are further used to prevent hydraulic shock. When an overload shock occurs, on the one hand, the electromagnetic unloading valve 19 and the safety valve 20 of the system are all opened to unload, and at the same time, the excess oil in the cylinder temporarily enters the safety accumulator 15 to reduce the peak impact pressure. The cylinder retreats under the load, and the roller gap expands, allowing abnormal materials to pass quickly to eliminate the overload shock.

[0024] After the impact, if the roll gap or roll deviation does not reach the maximum limit, the system will automatically recover and resume normal production; if the roll gap or roll deviation reaches the maximum limit, the main machine will trip and stop. At this time, the cause of the impact load should be checked and eliminated in time, and the equipment should be fully inspected. Restart the machine after no abnormality is found.

[0025] like Figure 1 As shown, the inner cavity of the oil tank 1 is divided into a clean side and an oil return side. The inner cavity of the clean side is connected to the oil outlet pipeline, and the inner cavity of the oil return side is connected to the oil return pipeline. The oil tank 1 is provided with a circulation pipeline 20 connecting the clean side and the oil return side. The circulation pipeline 20 is connected with a circulation pump 21, a circulation filter 22 and a cooler 23, so as to filter and cool the hydraulic oil on the oil return side before sending it to the clean side. By setting the circulation pipeline 20, the oil tank 1 has the function of oil self-purification, effectively improves the cleanliness of the oil, and reduces the wear of key components such as hydraulic system pumps and valves. In addition, the oil tank 1 is also provided with a thermometer 18, and the inner cavity of the clean side and the inner cavity of the oil return side are respectively provided with heaters 19 to further realize the temperature control of the oil tank 1.

[0026] The hydraulic system of this embodiment has independent control functions for the driving side and the non-driving side, roll gap correction function, constant pressure material extrusion function, safety accumulator overload limitation function and oil self-purification function, so that the roller press can run stably, safely and reliably, extend the service life of key components such as roller surface and bearings, and improve the stability and reliability of the hydraulic system of the roller press.

Claims

1. A roller press hydraulic system with improved safety performance, used for simultaneously supplying oil to a driving side cylinder (10) and a non-driving side cylinder (11) of a roller press, characterized in that: The invention comprises an oil tank (1), two electromagnetic reversing valves (5) and two groups of accumulators. The oil outlet pipeline of the oil tank (1) is respectively connected to the oil inlets of the two electromagnetic reversing valves (5), and the oil return pipeline of the oil tank (1) is respectively connected to the oil return ports of the two electromagnetic reversing valves (5). The working oil port of one electromagnetic reversing valve (5) is connected to the driving side cylinder (10) through the driving side pipeline (7), and the working oil port of the other electromagnetic reversing valve (5) is connected to the non-driving side cylinder (11) through the non-driving side pipeline (8). The driving side pipeline (7) and the non-driving side pipeline (8) are respectively connected to a group of accumulators. The same group of accumulators includes a working accumulator (14) in a normally open state. ) and two safety accumulators (15) in a normally closed state, a throttle valve (16) and two one-way valves (17) are provided between the three accumulators and the corresponding drive side pipeline (7) or non-drive side pipeline (8), one end of the throttle valve (16) is connected to the pipeline, the other end of the throttle valve (16) is connected to the three accumulators respectively, the inlet of the one-way valve (17) is connected to the pipeline, and the outlet of the one-way valve (17) is connected to the three accumulators respectively, so that the hydraulic oil in the pipeline can flow into the working accumulator (14) through the throttle valve (16) and the two one-way valves (17), and the hydraulic oil in the working accumulator (14) can flow into the pipeline through the throttle valve (16); The driving side pipeline (7) and the non-driving side pipeline (8) are respectively connected to a pressure sensor (13) on one side close to the oil cylinder. The driving side pipeline (7) and the non-driving side pipeline (8) are respectively connected to two branch pipelines of the unloading pipeline (9). The two branch pipelines of the unloading pipeline (9) are respectively connected to an electromagnetic unloading valve (6). When the pressure value of any pressure sensor (13) reaches a threshold value, the electromagnetic unloading valve (6) and the two safety accumulators (15) on the corresponding pipeline are switched to an open state, so that the hydraulic oil in the pipeline can flow into the two safety accumulators (15) and can flow back to the oil tank (1) through the unloading pipeline (9).

2. A roller press hydraulic system with improved safety performance according to claim 1, characterized in that: The working oil port of the electromagnetic reversing valve (5) is connected to an electromagnetic unloading valve (6), a safety valve is connected between the oil inlet and the oil return port of the electromagnetic reversing valve (5), and safety valves (12) are connected between two branch pipelines of the unloading pipeline (9) and the driving side pipeline (7) and the non-driving side pipeline (8) respectively.

3. A roller press hydraulic system with improved safety performance according to claim 1, characterized in that: The inner cavity of the oil tank (1) is divided into a clean side and an oil return side. The inner cavity of the clean side is connected to the oil outlet pipeline, and the inner cavity of the oil return side is connected to the oil return pipeline. A circulation pipeline (20) connecting the clean side and the oil return side is provided outside the oil tank (1). A circulation pump (21), a circulation filter (22) and a cooler (23) are connected to the circulation pipeline (20) so as to filter and cool the hydraulic oil on the oil return side before sending it to the clean side.

4. A roller press hydraulic system with improved safety performance according to claim 3, characterized in that: The oil tank (1) is provided with a thermometer (18), and the clean measuring inner cavity and the oil return side inner cavity are respectively provided with heaters (19).

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