A pressure-stabilizing hydraulic system for a roller press and a pressure regulation method

Abstract

This invention discloses a pressure-stabilizing hydraulic system and pressure regulation method for a roller press, relating to the technical field of roller press hydraulic systems. The hydraulic station system includes an oil tank, a piston pump, and a directional short-pipe valve. The left and right hydraulic systems adopt the same component arrangement. The left hydraulic system includes a left pilot-operated relief valve, a left switching valve, a left proportional relief valve, a left hydraulic cylinder assembly, and a left pressure sensor. The oil tank outlet, piston pump, and directional short-pipe valve are connected in sequence. The other end of the directional short-pipe valve is connected to the rod chamber of the left hydraulic cylinder assembly and the left switching valve, respectively. The rodless chamber of the left hydraulic cylinder assembly is connected to the left switching valve, the left proportional relief valve, and the left pressure sensor, respectively. The left pressure sensor is connected to the roller press control system. This roller press hydraulic system and pressure regulation method can effectively solve the problem of roller gap deviation, ensure a suitable hydraulic system working pressure value, and stabilize the roller press's work and grinding efficiency.

Description

Technical Field

[0001] This invention relates to the field of hydraulic systems for roller presses, and in particular to a pressure-stabilizing hydraulic system for roller presses and a pressure regulation method. Background Technology

[0002] A roller press is a high-efficiency and energy-saving grinding equipment based on the material bed crushing mechanism, and it has been widely used in industries such as cement, mining, and chemicals. The main components of a roller press are as follows: Figure 7 As shown, during operation, the movable roller 1 and the fixed roller 2 rotate relative to each other. The movable roller 1 moves horizontally forward and backward, with displacement changes S1 and S2 occurring on its left and right sides. Material 6 falls from above between the movable roller surface 4 and the fixed roller surface 5. The hydraulic cylinder module 3 applies high pressures P1 and P2, which are transmitted to the movable roller surface 4, causing the material to be squeezed between the movable roller surface 4 and the fixed roller surface 5. Since the hydraulic system provides the squeezing force acting on the material to achieve grinding, the performance of the hydraulic system directly affects the work done by the roller press, and thus the grinding efficiency of the system.

[0003] Currently, most roller presses on the market use a hydraulic system pressure range control method. The pressure range varies in size. During operation, the hydraulic system pressurizes the pressure to the upper limit of the range, monitors pressure changes, and when the pressure falls below the lower limit, the hydraulic system pressurizes again to the upper limit. This results in constant pressure fluctuations in the hydraulic system. In extreme cases, the system may remain at either the lower or upper limit of the pressure range, significantly impacting grinding efficiency. Furthermore, when encountering impact loads, the hydraulic system pressure of current roller presses surges, and existing systems struggle to buffer and release pressure promptly, leading to frequent leaks and damage to hydraulic pipelines and cylinders. Moreover, existing roller press hydraulic systems employ limited adjustment methods for different operating conditions, resulting in frequent issues such as large pressure deviations on the left and right sides of the movable rollers or the inability to adjust roller gap deviations. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a pressure self-stabilizing hydraulic system for a roller press and a pressure regulation method, which can effectively solve the roller gap deviation, ensure a suitable hydraulic system working pressure value, and stabilize the work and grinding efficiency of the roller press.

[0005] This invention proposes a pressure-stabilized hydraulic system for a roller press, comprising a hydraulic station system including an oil tank, a piston pump, and a directional short-pipe valve; the left and right hydraulic systems adopt the same component arrangement, the left hydraulic system including a left pilot-operated relief valve, a left switching valve, a left proportional relief valve, a left hydraulic cylinder assembly, and a left pressure sensor; the oil tank outlet, piston pump, and directional short-pipe valve are connected in sequence, the other end of the directional short-pipe valve is connected to the rod chamber of the left hydraulic cylinder assembly and the left switching valve respectively, the rodless chamber of the left hydraulic cylinder assembly is connected to the left switching valve, the left proportional relief valve, and the left pressure sensor respectively, and the left pressure sensor is connected to the roller press control system.

[0006] Furthermore, the hydraulic station system also includes a first relief valve, a second relief valve, an oil outlet filter, and a return oil filter. The directional short pipe valve is connected in parallel with the first relief valve and then connected to the oil tank through the return oil filter. The first relief valve and the second relief valve are connected in series and then connected to the piston pump through the oil outlet filter.

[0007] Furthermore, the hydraulic station system also includes a check valve, a manual shut-off valve at the oil tank outlet, a first manual shut-off valve, a second manual shut-off valve, and a first pressure gauge; the two ends of the check valve are respectively connected to the parallel node of the first relief valve and the second relief valve and the output end of the oil outlet filter; the manual shut-off valve at the oil tank outlet is located at the bottom of the oil tank; the first pressure gauge is connected to the parallel node of the first relief valve and the second relief valve; one end of the first manual shut-off valve is connected to the directional short pipe valve and the other end is connected to the left-side switch valve; one end of the second manual shut-off valve is connected to the directional short pipe valve and the other end is connected to the rod chamber of the left-side hydraulic cylinder assembly.

[0008] Furthermore, the left-side hydraulic system also includes an accumulator group, a first throttle valve, a second throttle valve, and a second pressure gauge; the first throttle valve is connected to the left-side pressure sensor and the left-side pilot-operated relief valve respectively; the rodless chamber of the left-side hydraulic cylinder assembly is connected to the accumulator group, the first throttle valve, and the second throttle valve respectively, and the second pressure gauge is connected to the second throttle valve.

[0009] Furthermore, the accumulator group includes a first accumulator, a second accumulator, a third accumulator, and a third manual shut-off valve; the first accumulator, the second accumulator, and the third accumulator are connected in parallel to the rodless chamber of the left hydraulic cylinder assembly, and the third manual shut-off valve is located between the first accumulator and the rodless chamber of the left hydraulic cylinder assembly.

[0010] Furthermore, the left-side hydraulic system also includes a left-side check valve, a fourth manual shut-off valve, and a fifth manual shut-off valve; one end of the left-side check valve is connected to the rodless chamber of the left-side hydraulic cylinder assembly, and the other end is connected to the left-side switch valve; one end of the fifth manual shut-off valve is connected to the rodless chamber of the left-side hydraulic cylinder assembly, and the other end is connected to the first throttle valve; one end of the fourth manual shut-off valve is connected to the second pressure gauge, and the other end is connected to the second throttle valve.

[0011] A hydraulic regulation method for a pressure-stabilized roller press includes:

[0012] S1: The roller press hydraulic system described above is used. The roller press is in operation, and the working pressure values ​​of the left and right hydraulic systems are set.

[0013] S2: Open the pilot-operated relief valves in the left and right hydraulic systems to perform automatic pressure relief operation;

[0014] S3: The roller press control system monitors the real-time pressure values ​​fed back by the pressure sensors in the left and right hydraulic systems. When the value is zero or less than the set threshold, proceed to step S4; otherwise, return to step S2.

[0015] S4: The hydraulic system automatically pressurizes according to the set pressure values ​​P1 and P2, where P1 is the set pressure value of the left hydraulic system and P2 is the set pressure value of the right hydraulic system.

[0016] S5: After pressurization is completed, perform the roller press feeding operation;

[0017] S6: After feeding is completed, the roller press control system monitors the left roller gap S1 and the right roller gap S2 of the moving roller in real time, and calculates the difference ΔS1S2 between S1 and S2. Based on the absolute value range of |ΔS1S2|, it performs self-stabilizing adjustment or dynamic adjustment control.

[0018] Furthermore, in step S6, when |ΔS1S2|≤4, self-stabilizing adjustment is performed, specifically as follows:

[0019] P1+0.1 and P2+0.1 are used as the system overflow values ​​of the left and right hydraulic systems, respectively, and P1-0.1 and P2-0.1 are used as the system pressure compensation values ​​of the left and right hydraulic systems, respectively.

[0020] When the pressure exceeds the system overflow value, the hydraulic system performs pressure relief; when the pressure is lower than the system pressure replenishment value, the hydraulic system performs pressure increase.

[0021] Furthermore, in step S6, if 4 < |ΔS1S2| ≤ 8, dynamic adjustment control is executed, specifically as follows:

[0022] Calculate the mean μ and standard deviation σ of ΔS1S2 within a set time T, where the set time T is the time it takes for a batch of material to completely pass through the roller press;

[0023] If the mean μ≥0 and the standard deviation σ≤1, the pressure setpoint P1+0.2 and P2 remain unchanged, and dynamic adjustment is performed.

[0024] If the mean μ≥0 and the standard deviation σ>1, the pressure setpoints P1+0.2 and P2-0.2 will be dynamically adjusted.

[0025] If the mean μ < 0 and the standard deviation σ ≤ 1, the pressure setpoint P2 + 0.2, while P1 remains unchanged, is dynamically adjusted.

[0026] If the mean μ < 0 and the standard deviation σ > 1, the pressure setpoints P2 + 0.2 and P1 - 0.2 will be dynamically adjusted.

[0027] Furthermore, if 8 < |ΔS1S2| ≤ 15, the active correction mode is entered. Specifically, if S1 > S2, the pressure setpoint P1 + ΔP and the pressure setpoint P2 - ΔP are adjusted to correct the deviation until 4 < |ΔS1S2| ≤ 8, then dynamic adjustment control is executed.

[0028] If |ΔS1S2|>15, the roller press control program will automatically stop the machine.

[0029] The advantages of the self-stabilizing hydraulic system and pressure regulation method for a roller press provided by this invention are: it can respond promptly to changes in hydraulic system pressure, quickly release and replenish pressure, and stabilize the pressure value at the set value, achieving self-stabilizing pressure regulation. Furthermore, this hydraulic system can control the switching of some accumulator circuits to adjust the stiffness of the hydraulic system and adapt to different working conditions. In addition, this hydraulic system employs a dynamic adjustment method and a combination of multiple strategies to address roller gap fluctuations caused by different working conditions, effectively solving roller gap deviations, ensuring a suitable hydraulic system working pressure value, and stabilizing the roller press's work and grinding efficiency. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the hydraulic system on the left.

[0032] Figure 3 Here is a flowchart of the pressure regulation method;

[0033] Figure 4 This is a flowchart of the pressure self-stabilization and regulation process;

[0034] Figure 5 For dynamic adjustment control flowchart;

[0035] Figure 6 Flowchart for the proactive correction mode;

[0036] Figure 7 This is a structural diagram of materials being rolled by an existing roller press;

[0037] Among them, 1. movable roller shaft, 2. fixed roller shaft, 3. hydraulic cylinder module, 4. movable roller surface, 5. fixed roller surface, 6. material, 10. hydraulic station system, 20. left hydraulic system, 30. right hydraulic system;

[0038] 1.1 First accumulator, 1.2 Second accumulator, 1.3 Third accumulator, 1.4 Fourth accumulator, 1.5 Fifth accumulator, 1.6 Sixth accumulator;

[0039] 2.1 First hydraulic cylinder on the left, 2.2 Second hydraulic cylinder on the left, 2.3 First hydraulic cylinder on the right, 2.4 Second hydraulic cylinder on the right;

[0040] 3.1 Left pressure sensor; 3.2 Right pressure sensor;

[0041] 4.1 Left-side pilot-operated relief valve; 4.2 Right-side pilot-operated relief valve;

[0042] 5.1 Left-side switch valve; 5.2 Right-side switch valve;

[0043] 6.1. Left proportional relief valve; 6.2. Right proportional relief valve;

[0044] 7.1 Directional short pipe valve;

[0045] 8.1. Plunger pump;

[0046] 9.1 First relief valve; 9.2 Second relief valve;

[0047] 10.1 Check valve; 10.2 Left check valve; 10.3 Right check valve;

[0048] 11.1 First throttle valve; 11.2 Third throttle valve; 11.3 Second throttle valve; 11.4 Fourth throttle valve;

[0049] 12.1 Fuel tank;

[0050] 13.1 Manual shut-off valve at the oil tank outlet;

[0051] 14.1 Third manual shut-off valve, 14.2 Sixth manual shut-off valve, 14.3 First manual shut-off valve, 14.4 Second manual shut-off valve, 14.5 Fourth manual shut-off valve, 14.6 Seventh manual shut-off valve, 14.7 Fifth manual shut-off valve, 14.8 Eighth manual shut-off valve;

[0052] 15.1 First pressure gauge; 15.2 Second pressure gauge; 15.3 Third pressure gauge;

[0053] 16.1 Oil outlet filter; 16.2 Oil return filter. Detailed Implementation

[0054] The technical solution of the present invention will now be described in detail through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0055] like Figures 1 to 7 As shown, the present invention proposes a pressure self-stabilizing hydraulic system and pressure regulation method for a roller press, including a hydraulic station system 10, a left hydraulic system 20, and a right hydraulic system 30. The hydraulic station system 10 includes an oil tank 12.1, a piston pump 8.1, and a directional short pipe valve 7.1. The left hydraulic system 20 and the right hydraulic system 30 adopt the same component arrangement. The left hydraulic system 20 includes a left pilot-operated relief valve 4.1, a left switching valve 5.1, a left proportional relief valve 6.1, a left hydraulic cylinder assembly, and a left pressure sensor 3.1. The oil outlet of the oil tank 12.1, the piston pump 8.1, and the directional short pipe valve 7.1 are connected in sequence. The other end of the directional short pipe valve 7.1 is connected to the rod chamber of the left hydraulic cylinder assembly and the left switching valve 5.1, respectively. The rodless chamber of the left hydraulic cylinder assembly is connected to the left switching valve 5.1, the left proportional relief valve 6.1, and the left pressure sensor 3.1, respectively. The left pressure sensor 3.1 is connected to the roller press control system.

[0056] The hydraulic station system 10 also includes a first relief valve 9.1, a second relief valve 9.2, an oil outlet filter 16.1, and a return oil filter 16.2. The directional short pipe valve 7.1 is connected in parallel with the first relief valve 9.1 and then connected to the oil tank 12.1 through the return oil filter 16.2. The first relief valve 9.1 and the second relief valve 9.2 are connected in series and then connected to the plunger pump 8.1 through the oil outlet filter 16.1.

[0057] The hydraulic station system 10 also includes a check valve 10.1, a manual shut-off valve 13.1 at the oil tank outlet, a first manual shut-off valve 14.3, a second manual shut-off valve 14.4, and a first pressure gauge 15.1;

[0058] The two ends of the one-way valve 10.1 are respectively connected to the parallel node of the first relief valve 9.1 and the second relief valve 9.2 and the output end of the oil outlet filter 16.1; the manual shut-off valve 13.1 of the oil tank outlet is located at the bottom of the oil tank 12.1; the first pressure gauge 15.1 is connected to the parallel node of the first relief valve 9.1 and the second relief valve 9.2; one end of the first manual shut-off valve 14.3 is connected to the directional short pipe valve 7.1 and the other end is connected to the left switch valve 5.1; one end of the second manual shut-off valve 14.4 is connected to the directional short pipe valve 7.1 and the other end is connected to the rod chamber of the left hydraulic cylinder assembly.

[0059] The left-side hydraulic system 20 also includes an accumulator group, a first throttle valve 11.1, a second throttle valve 11.3, and a second pressure gauge 15.2. The first throttle valve 11.1 is connected to the left-side pressure sensor 3.1 and the left-side pilot-operated relief valve 4.1. The rodless chamber of the left-side hydraulic cylinder assembly is connected to the accumulator group, the first throttle valve 11.1, and the second throttle valve 11.3, respectively. The second pressure gauge 15.2 is connected to the second throttle valve 11.3. The accumulator group includes a first accumulator 1.1, a second accumulator 1.2, a third accumulator 1.3, and a third manual shut-off valve 14.1. The first accumulator 1.1, the second accumulator 1.2, and the third accumulator 1.3 are connected in parallel to the rodless chamber of the left-side hydraulic cylinder assembly. The third manual shut-off valve 14.1 is located between the first accumulator 1.1 and the rodless chamber of the left-side hydraulic cylinder assembly.

[0060] The left hydraulic system 20 also includes a left check valve 10.2, a fourth manual shut-off valve 14.5, and a fifth manual shut-off valve 14.7; one end of the left check valve 10.2 is connected to the rodless chamber of the left hydraulic cylinder assembly, and the other end is connected to the left switch valve 5.1; one end of the fifth manual shut-off valve 14.7 is connected to the rodless chamber of the left hydraulic cylinder assembly, and the other end is connected to the first throttle valve 11.1; one end of the fourth manual shut-off valve 14.5 is connected to the second pressure gauge 15.2, and the other end is connected to the second throttle valve 11.3.

[0061] In this embodiment, since the left hydraulic system 20 and the right hydraulic system 30 use the same component arrangement, the right hydraulic system 30 also includes a right pilot-operated relief valve 4.2, a right on / off valve 5.2, a right proportional relief valve 6.2, a right hydraulic cylinder assembly, a right pressure sensor 3.2, a fourth accumulator 1.4, a fifth accumulator 1.5, a sixth accumulator 1.6, a sixth manual shut-off valve 14.2, a third throttle valve 11.2, a fourth throttle valve 11.4, a third pressure gauge 15.3, a right check valve 10.3, a seventh manual shut-off valve 14.6, and an eighth manual shut-off valve 14.8. The connection relationships between these components and with the hydraulic station system 10 are consistent with the structure in the left hydraulic system 20. Therefore, the connection relationships of the structure in the right hydraulic system 30 will not be described in detail in this embodiment.

[0062] The above six accumulators (1.1, 1.2, 1.3, 1.4, 1.5, 1.6) are used to absorb and buffer fluctuations in the hydraulic system, giving the system a certain degree of flexibility. The left pressure sensor 3.1 and the right pressure sensor 3.2 are used to provide feedback on the pressure of the left hydraulic system 20 and the right hydraulic system 30, and transmit it to the roller press control system.

[0063] Both the left-side hydraulic system 20 and the right-side hydraulic system 30 contain hydraulic cylinder assemblies. Specifically, the left-side hydraulic cylinder assembly includes a first hydraulic cylinder 2.1 and a second hydraulic cylinder 2.2, while the right-side hydraulic cylinder assembly includes a third hydraulic cylinder 2.3 and a fourth hydraulic cylinder 2.4. The first hydraulic cylinder 2.1 and the second hydraulic cylinder 2.2 are connected in parallel, as are the third hydraulic cylinder 2.3 and the fourth hydraulic cylinder 2.4. The left-side hydraulic cylinder assembly is used to adjust the left roll gap of the movable roller, and the right-side hydraulic cylinder assembly is used to adjust the right roll gap of the movable roller.

[0064] The left-side pilot-operated relief valve 4.1 and the right-side pilot-operated relief valve 4.2 are used for depressurization and relief control of the left-side hydraulic system 20 and the right-side hydraulic system 30. The left-side switching valve 5.1 and the right-side switching valve 5.2 are used for pressurization control of the left-side hydraulic system 20 and the right-side hydraulic system 30.

[0065] The left proportional relief valve 6.1 and the right proportional relief valve 6.2 are used for pressure relief and pressure stabilization control of the left hydraulic system 20 and the right hydraulic system 30. In this embodiment, the left proportional relief valve 6.1 and the right proportional relief valve 6.2 operate as follows: the roller press control system sends the set pressure values ​​P1 and P2 to the left proportional relief valve 6.1 and the right proportional relief valve 6.2, which then maintain their corresponding openings. If fluctuations occur in the hydraulic system, causing the pressure in the left hydraulic system 20 or the right hydraulic system 30 to exceed P1 or P2, the excess pressure does not need to be determined by the roller press control system; it is directly released through the left proportional relief valve 6.1 or the right proportional relief valve 6.2, enabling timely response to changes in hydraulic system pressure.

[0066] Directional short-pipe valve 7.1 is used for pressurization and roller retraction control of the left hydraulic system 20 and the right hydraulic system 30. First relief valve 9.1 and second relief valve 9.2 protect the hydraulic system by performing relief action when the pipeline pressure is too high. Check valve 10.1, left check valve 10.2, and right check valve 10.3 ensure that the hydraulic oil flow in the hydraulic system is unidirectional and does not backflow. First throttle valve 11.1, second throttle valve 11.3, third throttle valve 11.2, and fourth throttle valve 11.4 are used to control the flow rate of hydraulic oil through the pipeline, preventing damage to pressure gauges and sensors from high pressure surges. The hydraulic station's oil tank 12.1 is used to store hydraulic oil. A manual shut-off valve 13.1 is installed on the hydraulic station's oil tank 12.1 for discharging hydraulic oil. Manual shut-off valves 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, and 14.8 are used to close the current oil circuit.

[0067] The swashplate axial piston pump 8.1 provides pressurization power to the hydraulic system. In this embodiment, the swashplate axial piston pump 8.1 operates as follows: the roller press control system sends a set pressure value to the swashplate axial piston pump 8.1. When the oil pressure reaches the set pressure, the swashplate axial piston pump 8.1 maintains low-power operation and performs internal circulation. When the oil pressure falls below the set pressure, it performs external circulation, i.e., pressurization. It operates directly without requiring judgment from the roller press control system, enabling timely response to changes in hydraulic system pressure.

[0068] Since the left hydraulic system 20 and the right hydraulic system 30 adopt the same component arrangement, they have the functions of automatic pressurization, pressure relief, and pressure holding, and can also realize the roll retraction function, as shown in (a1) to (a4):

[0069] (a1) Automatic roll unwinding function: When performing roll unwinding operation, the swashplate axial piston pump 8.1 is working, the directional short pipe valve 7.1 is opening, and the hydraulic oil circuit between the directional short pipe valve 7.1, the second manual shut-off valve 14.4, and the rod chambers of hydraulic cylinders 2.1, 2.2, 2.3, and 2.4 is connected. At the same time, the left pilot-operated relief valve 4.1 and the right pilot-operated relief valve 4.2 are opening, connecting to the return oil circuit between the oil tank 12.1, thereby realizing roll unwinding.

[0070] (a2) To achieve automatic pressurization, when the pressure values ​​fed back by the left pressure sensor 3.1 and the right pressure sensor 3.2 do not reach the set pressure value, the directional short pipe valve 7.1, the left switch valve 5.1 and the right switch valve 5.2 will automatically open, and the swashplate axial piston pump 8.1 will work to pressurize the left hydraulic system 20 and the right hydraulic system 30. After reaching the set value, it will automatically stop.

[0071] (a3) To achieve automatic pressure relief function, after the working pressure of the left hydraulic system 20 and the right hydraulic system 30 is set, the left proportional relief valve 6.1 and the right proportional relief valve 6.2 are automatically adjusted to the corresponding threshold opening, and automatically overflow when the set working pressure is exceeded.

[0072] (a4) To achieve automatic pressure holding function, after the left hydraulic system 20 and the right hydraulic system 30 reach the set working pressure, the directional short pipe valve 7.1, the left switch valve 5.1 and the right switch valve 5.2, the left pilot-operated relief valve 4.1 and the right pilot-operated relief valve 4.2 are closed, and the left proportional relief valve 6.1 and the right proportional relief valve 6.2 are automatically adjusted to the corresponding threshold opening to stabilize the pressure of the left hydraulic system 20 and the right hydraulic system 30. When the pressure value fed back by the left pressure sensor 3.1 and the right pressure sensor 3.2 does not reach the set pressure value, the above-mentioned automatic pressurization operation is performed. When the pressure value fed back by the left pressure sensor 3.1 and the right pressure sensor 3.2 exceeds the set pressure value, the above-mentioned automatic depressurization operation is performed, and finally the automatic pressure holding operation is achieved.

[0073] Meanwhile, the hydraulic system of the roller press in this embodiment also has the ability to respond quickly to impact loads, as detailed in (b1) to (b2):

[0074] (b1) When the impact load is applied to the left hydraulic system 20 and the right hydraulic system 30 through hydraulic cylinders 2.1, 2.2, 2.3, and 2.4, the rodless chambers of hydraulic cylinders 2.1, 2.2, 2.3, and 2.4 are compressed, and the system pressure increases. Since the left proportional relief valve 6.1 and the right proportional relief valve 6.2 are always kept at the opening of the set values ​​P1 and P2, that is, always in the open state, the pressure exceeding the set values ​​P1 and P2 can be quickly overflowed and released through the left proportional relief valve 6.1 and the right proportional relief valve 6.2 without needing to be judged by the roller press control system, at the same time, the accumulators 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 absorb part of the impact, control the hydraulic oil flow in the control circuit, reduce the pressure amplitude of the left hydraulic system 20 and the right hydraulic system 30 under the impact load, and play a protective role for the hydraulic system and the roller surface of the roller press.

[0075] (b2) After the impact load passes, due to the overflow effect of the left proportional relief valve 6.1 and the right proportional relief valve 6.2, the left hydraulic system 20 and the right hydraulic system 30 need to be pressurized to ensure the system working pressure. Since the swashplate axial piston pump 8.1 is always running, when the pressure value is lower than the set value, it can quickly achieve the pressurization and oil replenishment action without the judgment of the roller press control system. At the same time, the impact released by the accumulators 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6 further replenishes the system pressure.

[0076] Therefore, according to (b1) to (b2), the hydraulic system of this embodiment has the ability to respond and adjust quickly when facing impact loads, stabilize the working pressure of the hydraulic system, and reduce the system pressure amplitude generated by the impact loads.

[0077] Furthermore, the hydraulic system in this embodiment also has the ability to adjust the stiffness of the hydraulic system. By adjusting the third manual shut-off valve 14.1 and the sixth manual shut-off valve 14.2, the first accumulator 1.1 and the fourth accumulator 1.4 can be engaged or disengaged, thereby adjusting the stiffness of the entire hydraulic system to adapt to different working conditions.

[0078] The hydraulic system of the roller press proposed in this embodiment adopts a combination design of proportional relief valve and swashplate axial piston pump to achieve rapid response of the hydraulic system to the impact load during the operation of the roller press, rapid buffering, release and replenishment of system pressure, and low pressure fluctuation. At the same time, the stiffness of the hydraulic system can be adjusted by manually shutting off a part of the accumulator circuit.

[0079] In this embodiment, the following is proposed: Figure 3 The hydraulic adjustment method for a pressure self-stabilizing roller press, as shown, includes the following steps S1 to S7:

[0080] S1: Using the above-mentioned hydraulic system for the roller press, the roller press is in operation, and the working pressure values ​​of the left hydraulic system 20 and the right hydraulic system 30 are set.

[0081] S2: The left hydraulic system 20 and the right hydraulic system 30 perform automatic pressure relief operation;

[0082] The automatic pressure relief operation is as follows: the left pilot-operated relief valve 4.1 in the left hydraulic system 20 is opened, and the right pilot-operated relief valve 4.2 in the right hydraulic system 30 is opened.

[0083] S3: The roller press control system monitors the real-time pressure values ​​fed back by the pressure sensors in the left hydraulic system 20 and the right hydraulic system 30. When the value is zero or less than the set threshold, proceed to step S4; otherwise, return to step S2.

[0084] Specifically, the roller press control system monitors the real-time pressure values ​​fed back by the left pressure sensor 3.1 and the right pressure sensor 3.2. When the value is zero or less than the set threshold (generally set to 0.5 to account for line signal interference), it determines that the pressure relief is complete; otherwise, it returns to step S2 to wait.

[0085] S4: The hydraulic system automatically pressurizes according to the set pressure values ​​P1 and P2, where P1 is the set pressure value of the left hydraulic system 20 and P2 is the set pressure value of the right hydraulic system 30.

[0086] After depressurization in step S3, the hydraulic system automatically pressurizes according to the set pressure values ​​P1 and P2. Specifically, the left switch valve 5.1 and the right switch valve 5.2 are opened, the directional short pipe valve 7.1 is connected to the oil circuit of the first manual shut-off valve 14.3, the swashplate axial piston pump 8.1 adjusts the mechanical threshold according to the set values ​​P1 and P2 and starts working. The roller press control system monitors the real-time pressure values ​​fed back by the left pressure sensor 3.1 and the right pressure sensor 3.2. When the value reaches the set pressure value P1, the left switch valve 5.1 is closed, and when the value reaches the set pressure value P2, the right switch valve 5.2 is closed, completing the pressurization.

[0087] S5: After pressurization is completed, perform the roller press feeding operation;

[0088] S6: After feeding is completed, the roller press control system monitors the left roller gap S1 and the right roller gap S2 of the real-time active roller (1), and calculates the difference ΔS1S2 between S1 and S2. Based on the absolute value range of |ΔS1S2|, it performs self-stabilizing adjustment or dynamic adjustment control.

[0089] S7, After the roller press finishes its work, the operator stops the machine.

[0090] Through steps S1 to S6, pressure self-stabilization and dynamic adjustment methods are used to specifically adjust the pressure of the hydraulic system of the roller press and the gap between the moving rollers, thereby improving the performance of the hydraulic system of the roller press and ensuring stable operation and grinding performance of the roller press.

[0091] In step S6, the self-stabilizing or dynamic adjustment control process specifically includes (c1) to (c4):

[0092] (c1) When |ΔS1S2|≤4, the roller press control system performs self-stabilizing adjustment;

[0093] like Figure 4 As shown, for the pressure P1 of the left hydraulic system 20, the roller press control system sends the automatic adjustment setpoint P1+0.1 as the overflow value of the left hydraulic system 20 to the left proportional relief valve 6.1. The left proportional relief valve 6.1 adjusts to the corresponding mechanical threshold. When the pressure exceeds P1+0.1, the hydraulic oil automatically flows through the left proportional relief valve 6.1 back to the oil tank 12.1. The automatic adjustment P1-0.1 is used as the automatic pressurization value of the left hydraulic system 20. When the pressure is lower than P1-0.1, the left switch valve 5.1 opens, the directional short pipe valve 7.1 connects to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 operates. When the pressure reaches P1+0.1, the left switch valve 5.1 closes, disconnecting the oil circuit between the directional short pipe valve 7.1 and the first manual shut-off valve 14.3. This stabilizes the pressure value of the left hydraulic system 20.

[0094] For the right-side hydraulic system 30 pressure P2, the roller press control system sends the automatic adjustment setpoint P2+0.1 as the overflow value of the right-side hydraulic system 30 to the right-side proportional relief valve 6.2. The right-side proportional relief valve 6.2 adjusts to the corresponding mechanical threshold. When the pressure exceeds P2+0.1, the hydraulic oil automatically flows through the right-side proportional relief valve 6.2 back to the oil tank 12.1. The automatic adjustment P2-0.1 is used as the automatic pressurization value for the right-side hydraulic system 30. When the pressure is lower than P2-0.1, the right-side switch valve 5.2 opens, the directional short pipe valve 7.1 connects to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 operates. When the pressure reaches P2+0.1, the right-side switch valve 5.2 closes, disconnecting the oil circuit between the directional short pipe valve 7.1 and the first manual shut-off valve 14.3. This stabilizes the pressure value of the right-side hydraulic system 30.

[0095] (c2) When 4 < |ΔS1S2| ≤ 8, execute dynamic adjustment control;

[0096] like Figure 5 and 6 As shown, the mean μ and standard deviation σ of ΔS1S2 within the calculation time T are calculated. Time T is the time it takes for one batch of material to completely pass through the roller press, which is taken as 120 s here. The mean μ and standard deviation σ of the calculation results have the following cases (d1) to (d4):

[0097] (d1) If the mean μ≥0 and the standard deviation σ≤1, increase the pressure setpoint P1 by 0.2 and keep P2 unchanged;

[0098] The automatic adjustment setpoint P1+0.2 is sent as the overflow value of the left hydraulic system 20 to the left proportional relief valve 6.1, and the left proportional relief valve 6.1 is adjusted to the corresponding mechanical threshold.

[0099] The left hydraulic system 20 is pressurized, the left switch valve 5.1 is opened, the directional short pipe valve 7.1 is connected to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 is working. When the pressure reaches P1+0.2, the left switch valve 5.1 is closed, and the oil circuit of the directional short pipe valve 7.1 and the first manual shut-off valve 14.3 is disconnected.

[0100] (d2) If the mean μ≥0 and the standard deviation σ>1, increase the pressure setpoint P1+0.2 and decrease P2-0.2;

[0101] The automatic adjustment setpoint P1+0.2 is sent to the left proportional relief valve 6.1 as the overflow value of the left hydraulic system 20. The left proportional relief valve 6.1 is adjusted to the corresponding mechanical threshold.

[0102] The left hydraulic system 20 is pressurized, the left switch valve 5.1 is opened, the directional short pipe valve 7.1 is connected to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 is working. When the pressure reaches P1+0.2, the left switch valve 5.1 is closed, and the oil circuit of the directional short pipe valve 7.1 and the first manual shut-off valve 14.3 is disconnected.

[0103] The right hydraulic system 30 is depressurized, and the automatic adjustment set value P2-0.2 is sent to the right proportional relief valve 6.2 as the overflow value of the right hydraulic system 30. The right proportional relief valve 6.2 is adjusted to the corresponding mechanical threshold and automatically overflows to the set value P2-0.2.

[0104] (d3) If the mean μ < 0 and the standard deviation σ ≤ 1, increase the pressure setpoint P2 by 0.2 and keep P1 unchanged;

[0105] The automatic adjustment setpoint P2+0.2 is sent to the right proportional relief valve 6.2 as the overflow value of the right hydraulic system 30. The right proportional relief valve 6.2 is then adjusted to the corresponding mechanical threshold.

[0106] The right hydraulic system 30 is pressurized, the right switch valve 5.2 is opened, the directional short pipe valve 7.1 is connected to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 is working. When the pressure reaches P2+0.2, the right switch valve 5.2 is closed, and the oil circuit of the directional short pipe valve 7.1 and the first manual shut-off valve 14.3 is disconnected.

[0107] (d4) If the mean μ < 0 and the standard deviation σ > 1, increase the pressure setpoint P2 by 0.2 and decrease P1 by 0.2;

[0108] The automatic adjustment setpoint P2+0.2 is sent to the right proportional relief valve 6.2 as the overflow value of the right hydraulic system 30. The right proportional relief valve 6.2 is then adjusted to the corresponding mechanical threshold.

[0109] The right hydraulic system 30 is pressurized, the right switch valve 5.2 is opened, the directional short pipe valve 7.1 is connected to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 is working. When the pressure reaches P2+0.2, the right switch valve 5.2 is closed, and the oil circuit of the directional short pipe valve 7.1 and the first manual shut-off valve 14.3 is disconnected.

[0110] The left hydraulic system 20 is depressurized, and the automatic adjustment set value P1-0.2 is sent to the left proportional relief valve 6.1 as the overflow value of the left hydraulic system 20. The left proportional relief valve 6.1 is adjusted to the corresponding mechanical threshold and automatically overflows to the set value P1-0.2.

[0111] (c3) If 8 < |ΔS1S2| ≤ 15, enter active correction mode, specifically:

[0112] like Figure 6 As shown, if S1>S2, the pressure setting value P1+ΔP is increased, and the pressure setting value P2-ΔP is decreased. In this embodiment, ΔP is preferably 0.5MPa.

[0113] The automatic adjustment setpoint P1+ΔP is sent as the overflow value of the left hydraulic system 20 to the left proportional relief valve 6.1, and the left proportional relief valve 6.1 is adjusted to the corresponding mechanical threshold.

[0114] The left hydraulic system 20 is pressurized, the left switch valve 5.1 is opened, the directional short pipe valve 7.1 is connected to the oil circuit of the first manual shut-off valve 14.3, and the swashplate axial piston pump 8.1 is working. When the pressure reaches P1+ΔP, the left switch valve 5.1 is closed, and the oil circuit of the directional short pipe valve 7.1 and the first manual shut-off valve 14.3 is disconnected.

[0115] The right hydraulic system 30 is depressurized, and the automatic adjustment set value P2-ΔP is sent to the right proportional relief valve 6.2 as the overflow value of the right hydraulic system 30. The right proportional relief valve 6.2 is adjusted to the corresponding mechanical threshold and automatically overflows to the set value P2-ΔP.

[0116] (c4) If |ΔS1S2|>15, the roller press control program will automatically stop the machine.

[0117] By using (c1) to (c4), the hydraulic system working pressure is set to a single value instead of a range. Based on the single value control, a self-stabilizing adjustment method is proposed to address small fluctuations under stable operating conditions, thereby stabilizing the hydraulic system working pressure. Simultaneously, different adjustment strategies are adopted for different ranges of the roller gap difference, effectively solving the problem of large roller gap deviation during roller press operation, while ensuring that the working pressure is at a suitable set value.

[0118] In summary, this embodiment can respond promptly to fluctuations in hydraulic system pressure, quickly release and replenish pressure, achieve self-stabilizing adjustment under small fluctuations in the hydraulic system, and employ dynamic adjustment methods for other different operating conditions. The combination of multiple strategies can effectively solve the problem of roller gap deviation, ensure the appropriate hydraulic system working pressure value, and ensure the working stability and grinding performance of the roller press.

[0119] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A hydraulic adjustment method for a pressure-self-stabilizing roller press, characterized in that, The roller press hydraulic system is used, which includes a hydraulic station system (10), including an oil tank (12.1), a piston pump (8.1), and a directional short pipe valve (7.1). The left hydraulic system (20) and the right hydraulic system (30) use the same component arrangement; The left hydraulic system (20) includes a left pilot-operated relief valve (4.1), a left on / off valve (5.1), a left proportional relief valve (6.1), a left hydraulic cylinder assembly, and a left pressure sensor (3.1). The oil outlet of the oil tank (12.1), the plunger pump (8.1) and the directional short pipe valve (7.1) are connected in sequence. The other end of the directional short pipe valve (7.1) is connected to the rod chamber of the left hydraulic cylinder assembly and the left switch valve (5.1). The rodless chamber of the left hydraulic cylinder assembly is connected to the left switch valve (5.1), the left proportional relief valve (6.1) and the left pressure sensor (3.1). The left pressure sensor (3.1) is connected to the roller press control system. The hydraulic adjustment method includes: S1: The roller press is in operation. Set the working pressure values ​​of the left hydraulic system (20) and the right hydraulic system (30); S2: Open the pilot relief valves in the left hydraulic system (20) and the right hydraulic system (30) to perform automatic pressure relief operation; S3: The roller press control system monitors the real-time pressure values ​​fed back by the pressure sensors in the left hydraulic system (20) and the right hydraulic system (30). When the value is zero or less than the set threshold, proceed to step S4; otherwise, return to step S2. S4: The hydraulic system automatically pressurizes according to the set pressure values ​​P1 and P2, where P1 is the set pressure value of the left hydraulic system (20) and P2 is the set pressure value of the right hydraulic system (30). S5: After pressurization is completed, perform the roller press feeding operation; S6: After feeding is completed, the roller press control system monitors the left roller gap S1 and the right roller gap S2 of the moving roller (1) in real time, and calculates the difference ΔS1S2 between S1 and S2. Based on the absolute value range of |ΔS1S2|, it performs self-stabilizing adjustment or dynamic adjustment control.

2. The hydraulic adjustment method for a roller press according to claim 1, characterized in that, The hydraulic station system (10) also includes a first relief valve (9.1), a second relief valve (9.2), an oil outlet filter (16.1), and a return oil filter (16.2). The directional short pipe valve (7.1) is connected in parallel with the first relief valve (9.1) and then connected to the oil tank (12.1) through the return oil filter (16.2). The first relief valve (9.1) and the second relief valve (9.2) are connected in series and then connected to the plunger pump (8.1) through the oil outlet filter (16.1).

3. The hydraulic adjustment method for a roller press according to claim 1, characterized in that, The hydraulic station system (10) also includes a check valve (10.1), a manual shut-off valve (13.1) at the oil tank outlet, a first manual shut-off valve (14.3), a second manual shut-off valve (14.4), and a first pressure gauge (15.1). The two ends of the one-way valve (10.1) are connected to the parallel node of the first relief valve (9.1) and the second relief valve (9.2) and the output end of the oil filter (16.1), respectively; The manual shut-off valve (13.1) at the oil tank outlet is located at the bottom of the oil tank (12.1); The first pressure gauge (15.1) is connected to the parallel node of the first relief valve (9.1) and the second relief valve (9.2); One end of the first manual shut-off valve (14.3) is connected to the directional short pipe valve (7.1), and the other end is connected to the left-side switch valve (5.1); One end of the second manual shut-off valve (14.4) is connected to the directional short pipe valve (7.1), and the other end is connected to the rod chamber of the left hydraulic cylinder assembly.

4. The hydraulic adjustment method for a roller press according to claim 1, characterized in that, The left-side hydraulic system (20) also includes an accumulator group, a first throttle valve (11.1), a second throttle valve (11.3), and a second pressure gauge (15.2). The first throttle valve (11.1) is connected to the left pressure sensor (3.1) and the left pilot-operated relief valve (4.1) respectively; The rodless chamber of the left hydraulic cylinder assembly is connected to the accumulator group, the first throttle valve (11.1), and the second throttle valve (11.3), respectively. The second pressure gauge (15.2) is connected to the second throttle valve (11.3).

5. The hydraulic adjustment method for a roller press according to claim 4, characterized in that, The accumulator group includes a first accumulator (1.1), a second accumulator (1.2), a third accumulator (1.3), and a third manual shut-off valve (14.1). The first accumulator (1.1), the second accumulator (1.2), and the third accumulator (1.3) are connected in parallel to the rodless chamber of the left hydraulic cylinder assembly. The third manual shut-off valve (14.1) is located between the first accumulator (1.1) and the rodless chamber of the left hydraulic cylinder assembly.

6. The hydraulic adjustment method for a roller press according to claim 1, characterized in that, The left-side hydraulic system (20) also includes a left-side check valve (10.2), a fourth manual shut-off valve (14.5), and a fifth manual shut-off valve (14.7). One end of the left-side check valve (10.2) is connected to the rodless chamber of the left-side hydraulic cylinder assembly, and the other end is connected to the left-side switching valve (5.1). One end of the fifth manual shut-off valve (14.7) is connected to the rodless chamber of the left hydraulic cylinder assembly, and the other end is connected to the first throttle valve (11.1); One end of the fourth manual shut-off valve (14.5) is connected to the second pressure gauge (15.2), and the other end is connected to the second throttle valve (11.3).

7. The hydraulic adjustment method for a roller press according to claim 1, characterized in that, In step S6, when |ΔS1S2|≤4, self-stabilizing adjustment is performed, specifically as follows: P1+0.1 and P2+0.1 are used as the system overflow values ​​of the left hydraulic system (20) and the right hydraulic system (30) respectively, and P1-0.1 and P2-0.1 are used as the system pressure compensation values ​​of the left hydraulic system (20) and the right hydraulic system (30) respectively. When the pressure exceeds the system overflow value, the hydraulic system performs pressure relief; when the pressure is lower than the system pressure replenishment value, the hydraulic system performs pressure increase.

8. The hydraulic adjustment method for a roller press according to claim 1, characterized in that, In step S6, if 4 < |ΔS1S2| ≤ 8, dynamic adjustment control is executed, specifically as follows: Calculate the mean µ and standard deviation σ of ΔS1S2 within a set time T, where the set time T is the time it takes for a batch of material to completely pass through the roller press; If the mean µ≥0 and the standard deviation σ≤1, the pressure setpoint P1+0.2 and P2 remain unchanged, and dynamic adjustment is performed. If the mean µ≥0 and the standard deviation σ>1, the pressure setpoints P1+0.2 and P2-0.2 will be dynamically adjusted. If the mean µ < 0 and the standard deviation σ ≤ 1, the pressure setpoint P2 + 0.2 is increased while P1 remains unchanged, and dynamic adjustment is performed. If the mean µ < 0 and the standard deviation σ > 1, the pressure setpoints P2 + 0.2 and P1 - 0.2 will be dynamically adjusted.

9. The hydraulic adjustment method for a roller press according to claim 8, characterized in that, In step S6, if 8 < |ΔS1S2| ≤ 15, the active correction mode is entered. Specifically, if S1 > S2, the pressure setpoint P1 is increased by ΔP and the pressure setpoint P2 is decreased by ΔP to perform correction adjustment until 4 < |ΔS1S2| ≤ 8, then dynamic adjustment control is executed. If |ΔS1S2|>15, the roller press control program will automatically stop the machine.

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