Self-adaptive pressure compensation control system of temperature control hydraulic oil press based on Internet of Things

Abstract

The invention relates to the technical field of oil press pressure compensation, in particular to a temperature control hydraulic oil press self-adaptive pressure compensation control system based on the Internet of Things. The system comprises a pressure applying mechanism, an oil monitoring mechanism, a pressure compensation mechanism, a controller and a parameter adjusting mechanism. The automatic squeezing process is monitored, the squeezing pressure is accurately compensated in the pressure maintaining stage, the real-time oil outlet rate is calculated through the weighing sensor, the influence of the squeezing pressure on the oil outlet efficiency is accurately analyzed, whether the current squeezing process is switched from the pressure increasing stage to the pressure maintaining stage or not is judged according to the real-time squeezing pressure, and the oil outlet efficiency is improved. And the reason of low oil extraction efficiency is analyzed so as to adaptively optimize pressing parameters, that is, when the oil extraction efficiency is low, the pressure increasing rate of the next pressing process is accurately optimized according to the actual cake residual oil rate by quickly positioning the root of material leakage and blockage faults and giving a clear optimization direction so as to guarantee the high efficiency of pressure compensation.

Description

Technical Field

[0001] This invention relates to the field of pressure compensation technology for oil presses, and in particular to an adaptive pressure compensation control system for a temperature-controlled hydraulic oil press based on the Internet of Things. Background Technology

[0002] Oil pressing equipment can be divided into screw oil presses and hydraulic oil presses. Screw oil presses can easily achieve continuous pressing operations, but the heat generated by friction between materials, between materials and the screw, and between materials and the press bars during the pressing process is not easily dissipated. This causes the temperature of the materials to rise during the pressing process, destroying heat-sensitive substances and protein in the oil, reducing its nutritional value. At the same time, for high-oil-content materials such as walnuts, screw pressing is prone to "slippage," resulting in an unformed cake that is muddy and does not extract oil. If the shell is pressed, the problem of cake formation can be solved, but the cake contains oil and fiber, rendering it inedible and only suitable for animal feed. Hydraulic oil presses do not have the above problems. They use the principle of hydrostatic pressure transmission, with liquid as the pressure transmission medium to provide power, to squeeze the oilseeds to extract oil. Hydraulic oil presses are characterized by simple structure, good quality and flavor of pressed oil, and good cake quality, but they also have the problem of higher residual oil in the cake.

[0003] Chinese Patent Publication No. CN112659617A discloses an intelligent low-temperature screw oil press with a pressure monitoring device. The press includes a frame with a screw shaft inside the pressing chamber, connected to a motor via a reducer. A pressing cage is fitted onto the screw shaft, with several oil filtration sections. The press also includes a pressure monitoring unit, a temperature monitoring unit, a cooling unit, and an automatic control system. The pressure monitoring unit is located within each oil filtration section of the pressing cage and monitors the pressure data of each section in real time. The automatic control system controls and adjusts the feeding speed and main shaft speed based on the received pressure data. The temperature monitoring unit monitors the temperature data at different locations within the pressing chamber and sends it to the automatic control system. The cooling unit ensures the pressing chamber remains in a low-temperature environment based on control signals from the automatic control system. Therefore, existing oil press control systems suffer from low production efficiency and high residual oil content due to reliance on manual experience and fixed process parameters. They also cannot adapt to the characteristics of different batches of raw materials, resulting in low intelligence in the pressing process. Summary of the Invention

[0004] To address this issue, the present invention provides an adaptive pressure compensation control system for a temperature-controlled hydraulic oil press based on the Internet of Things, which overcomes the problem in the prior art of lacking automatic fault diagnosis of correlation between oil extraction efficiency and pressure increase rate, thus enabling the pressing process to adapt to low pressure.

[0005] To achieve the above objectives, the present invention provides an adaptive pressure compensation control system for a temperature-controlled hydraulic oil press based on the Internet of Things, comprising: The pressure-applying mechanism is used to apply a preset propulsion pressure to each pressing chamber during the pressurization stage; An oil monitoring device is installed on the oil receiving tank to calculate the real-time oil output rate of walnut pulp and to plot the oil output rate change curve based on the real-time oil output rate. A pressure compensation mechanism, which is connected to the pressure application mechanism, is used to compensate for the pressure decay in the pressing chamber based on the current signal of the regulating proportional overflow valve during the pressure holding stage. The controller is connected to the pressure application mechanism, the oil monitoring mechanism and the pressure compensation mechanism respectively, and is used to determine whether the current pressing process has changed from the pressure increase stage to the pressure holding stage based on the oil output rate change curve, and to analyze the pressure change trend in each pressing chamber based on the real-time gap distance to obtain the pressure fluctuation factor. A parameter adjustment mechanism, connected to the controller, is used to adjust the pressurization rate of the next pressing process based on a comparison between the pressure fluctuation factor and the pressure fluctuation threshold.

[0006] Furthermore, the oil monitoring mechanism includes a weighing unit and a calculation unit; The weighing unit is used to obtain the cumulative oil mass in the oil receiving tank. The calculation unit is used to calculate the real-time oil output rate based on the cumulative oil quality; The real-time oil output rate is the product of the cumulative increase in oil quality and the sampling time interval, and the cumulative increase in oil quality is the difference between the cumulative oil quality at the current moment and the cumulative oil quality at the previous moment.

[0007] Furthermore, the pressure compensation mechanism includes a pressure deviation monitoring unit and a current response unit; The pressure deviation monitoring unit is used to calculate the real-time pressure decay value inside the pressing chamber; The current response unit responds to the real-time pressure decay value based on the PID control algorithm to obtain the control current adjustment value.

[0008] Furthermore, the current response unit includes a current calculation subunit and a response subunit; The current calculation subunit is used to calculate the control current adjustment value based on the PID control algorithm and the real-time pressure decay value; The response subunit is used to adjust the control current of the proportional relief valve to the control current adjustment value.

[0009] Furthermore, the controller includes an oil extraction rate analysis unit, a gap monitoring unit, a pressing state analysis unit, and a pressure change analysis unit; The oil output rate analysis unit is used to determine the oil output efficiency based on the oil output rate change curve, and obtain a first determination result and a second determination result. The pressing status analysis unit is used to determine whether a pressing abnormality has occurred based on the judgment result and the current stage of the pressing process. The gap monitoring unit is used to respond to the occurrence of pressing abnormalities, obtain the real-time gap distance between the pressing ring and the pressing plate, and determine whether material leakage has occurred based on the comparison result of the real-time gap distance and the standard gap distance. The pressure change analysis unit is used to obtain the pressure fluctuation factor within a preset monitoring period in response to the real-time gap distance being less than or equal to the standard gap distance, so as to temporarily depressurize the pressing chamber or adjust the pressurization rate of the next pressing process based on the pressure fluctuation factor.

[0010] Furthermore, the oil output rate analysis unit obtains the real-time slope of the oil output rate change curve for determination: If the real-time slope is less than the standard slope, the first judgment result is obtained; If the real-time slope is greater than or equal to the standard slope, a second determination result is obtained.

[0011] Furthermore, the pressing state analysis unit includes a pressing state judgment unit and a pressing process analysis unit; The pressing status determination unit responds to the first determination result and determines that the pressing status is normal, and continues monitoring. The pressing process analysis unit responds to the second determination result and determines the real-time pressing pressure according to the standard pressing pressure range in order to analyze the current stage of the pressing process and thus determine whether a pressing abnormality has occurred.

[0012] Furthermore, the pressure change analysis unit includes a pressure curve plotting unit, a pressure curve analysis unit, and a pressure factor calculation unit; The pressure curve plotting unit plots the real-time pressing pressure change curves corresponding to each collection point over time, thus obtaining the pressing pressure change curves. The pressure curve analysis unit is used to acquire collection points in the pressing pressure change curve that do not fall within the standard fluctuation range of pressing pressure, and these points are marked as abnormal fluctuation points. The pressure factor calculation unit is used to calculate the pressure fluctuation factor based on the abnormal fluctuation point. Among them, the pressure fluctuation factor is the percentage of abnormal fluctuation points out of the total number of data collection points.

[0013] Furthermore, the parameter adjustment mechanism includes a first adjustment unit, a second adjustment unit, and a third adjustment unit; The first adjustment unit responds to the real-time gap distance being greater than the standard gap distance by reducing the pressurization rate of the next pressing process to the first corrected pressurization rate; The second adjustment unit responds to the pressure fluctuation factor being greater than the pressure fluctuation threshold by increasing the pressurization rate of the next pressing process to the second corrected pressurization rate; The third adjustment unit responds to the pressure fluctuation factor being less than or equal to the pressure fluctuation threshold by increasing the pressurization rate of the next pressing process to the third corrected pressurization rate.

[0014] Furthermore, the parameter adjustment mechanism also includes a correction parameter calculation unit; The correction parameter calculation unit is used to calculate the pressurization rate for the next pressing process based on the actual cake residual oil rate.

[0015] Compared with the prior art, the beneficial effects of the present invention are that by monitoring the automatic pressing process, the pressing pressure is accurately compensated during the pressure holding stage, and the real-time oil output rate is calculated by the weighing sensor to accurately analyze the impact of pressing pressure on oil output efficiency. That is, when the oil output efficiency is low, the source of leakage and blockage can be quickly located and a clear optimization direction can be given, reducing downtime for troubleshooting. Furthermore, the pressurization rate of the next batch can be optimized based on the pressing conditions of the current batch to ensure the high efficiency of pressure compensation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the adaptive pressure compensation control system for a temperature-controlled hydraulic oil press based on the Internet of Things, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the oil monitoring mechanism according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the pressure compensation mechanism according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the controller in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0018] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0020] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] Please see Figure 1 The diagram shown is a structural schematic of an adaptive pressure compensation control system for a temperature-controlled hydraulic oil press based on the Internet of Things (IoT) according to an embodiment of the present invention. The present invention provides an adaptive pressure compensation control system for a temperature-controlled hydraulic oil press based on the Internet of Things (IoT), comprising: The pressure-applying mechanism is used to apply a preset propulsion pressure to each pressing chamber during the pressurization stage; An oil monitoring device is installed on the oil receiving tank to calculate the real-time oil output rate of walnut pulp and to plot the oil output rate change curve based on the real-time oil output rate. A pressure compensation mechanism, which is connected to the pressure application mechanism, is used to compensate for the pressure decay in the pressing chamber based on the current signal of the regulating proportional overflow valve during the pressure holding stage. The controller is connected to the pressure application mechanism, the oil monitoring mechanism and the pressure compensation mechanism respectively, and is used to determine whether the current pressing process has changed from the pressure increase stage to the pressure holding stage based on the oil output rate change curve, and to analyze the pressure change trend in each pressing chamber based on the real-time gap distance to obtain the pressure fluctuation factor. A parameter adjustment mechanism, connected to the controller, is used to adjust the pressurization rate of the next pressing process based on a comparison between the pressure fluctuation factor and the pressure fluctuation threshold.

[0022] In this embodiment, the automatic pressing process is monitored, and the pressing pressure is precisely compensated during the holding pressure stage. The real-time oil output rate is calculated using a weighing sensor to accurately analyze the impact of pressing pressure on oil output efficiency. Specifically, when the oil output efficiency is low, the source of leakage and blockage can be quickly located and a clear optimization direction can be given, reducing downtime for troubleshooting. Furthermore, the pressurization rate of the next batch can be optimized based on the pressing conditions of the current batch to ensure the high efficiency of pressure compensation.

[0023] In this embodiment, a temperature control mechanism is also provided to maintain the temperature of the pressing chamber at a preset pressing temperature of 60°C. This pressing temperature is maintained by adjusting the opening of the steam valve or the power of the electric heater. The pressing process is as follows: the main oil cylinder is controlled to pressurize the pressing chamber at a preset pushing pressure of 23MPa until the target pressing pressure of 50MPa is reached to press the material. During the pressing process, the oil extraction rate is monitored in real time, and it is determined whether the pressing process has transitioned from the pressurization stage to the pressure holding stage based on the real-time pressing pressure. The reasons for low oil extraction efficiency are analyzed to adaptively optimize the pressing parameters. After pressing, the residual oil rate of the cake is accurately calculated based on the actual residual oil rate. The pressurization rate of the next pressing process; multiple pressing chambers form a pressing chamber group. Each pressing chamber consists of a pressing plate, a pressing ring, and a pressing chamber end panel. The pressing chambers are connected in series. The pressing plate is located on the left side of the pressing chamber and is connected to the piston rod of the main oil cylinder. During the pressing process, it is pushed to the right by the main oil cylinder to squeeze the material. At the same time, it acts as the end panel of the adjacent pressing chamber to realize pressure transmission. The pressing ring is located on the right side of the pressing plate and can move axially along the cylindrical guide rail. It is equipped with a feed port on top for material to enter. A spring device is provided between it and the pressing plate to keep the pressing chamber sealed and automatically reset. During the cake unloading process, it is pushed to the left by the auxiliary oil cylinder to open the pressing chamber and allow the cake to fall off under the action of gravity.

[0024] Specifically, this embodiment also provides a pressing process for a temperature-controlled hydraulic oil press, applied to the adaptive pressure compensation control system in this embodiment, including: Step S1, feeding; includes: Step S101: Raw material pretreatment, drying the raw materials to control the moisture content to 2%; Step S102, grinding: The pretreated raw materials are ground using a pulverizer to obtain walnut pulp; Step S103, pumping: pump the walnut pulp into the material conveying main pipe above the press, so that the walnut pulp enters the feed port above each pressing chamber through the distributor; Step S104, sealing: In response to the weight sensor determining that the pressing chamber is filled with walnut pulp, the cylinder push rod is controlled to move downward to seal the feed port. Step S2, automatic pressing: apply a preset pushing pressure to the pressing chamber to squeeze the material in each pressing chamber so that the walnut pulp forms oil and flows out; Among these measures, the automatic pressing process is monitored to determine whether the pressurization rate should be optimized for the next pressing cycle. Step S3, cake unloading: After pressing is completed, control the opening of each pressing chamber so that the walnut meal in the pressing chamber falls into the cake receiving trough below the pressing chamber, thus completing the automatic cake unloading. Step S4: Reset and depressurize the auxiliary oil cylinder to allow each pressing chamber to close again and enter the next pressing process.

[0025] The press in this embodiment is used to prepare walnut oil, and can also be used to prepare sesame oil and rapeseed oil. Compared with granules and powder, walnut pulp has better fluidity and is less prone to accumulation and bridging during feeding. However, if the pressurization rate is too slow, the pulp will quickly form an effective pressure-bearing structure, and the material will not be effectively compressed. The pressure in the pressing chamber is difficult to reach and stabilize at the target value, and the pressure compensation is frequently activated. In this case, although the compensation mechanism works frequently, since the physical state of the material has not changed fundamentally, that is, a dense cake structure has not been formed, most of the energy is consumed in ineffective pushing rather than effective pressing, which makes the oil outflow path obstructed and results in a high residual oil rate in the cake. Therefore, by finding and setting the optimal pressurization rate, fully automatic and efficient pressing can be achieved.

[0026] See Figure 2 As shown, it is a structural schematic diagram of the oil monitoring mechanism in an embodiment of the present invention; Specifically, the oil monitoring mechanism includes a weighing unit and a calculation unit; The weighing unit is used to obtain the cumulative oil mass in the oil receiving tank. The calculation unit is used to calculate the real-time oil output rate based on the cumulative oil quality; The real-time oil output rate is the product of the cumulative increase in oil quality and the sampling time interval, and the cumulative increase in oil quality is the difference between the cumulative oil quality at the current moment and the cumulative oil quality at the previous moment.

[0027] In this embodiment, the real-time oil extraction rate of walnut pulp is obtained by a weighing sensor installed in the oil receiving tank. Through precise direct weighing and simple calculation, the pressing process is quantified, providing accurate judgment basis.

[0028] See Figure 3 As shown, it is a structural schematic diagram of the pressure compensation mechanism according to an embodiment of the present invention; Specifically, the pressure compensation mechanism includes a pressure deviation monitoring unit and a current response unit; The pressure deviation monitoring unit is used to calculate the real-time pressure decay value inside the pressing chamber; The current response unit responds to the real-time pressure decay value based on the PID control algorithm to obtain the control current adjustment value.

[0029] In this embodiment, as the oil is continuously squeezed out and the material cake is further compressed, the physical space inside the pressing chamber increases slightly, which in turn causes the pressure in the hydraulic system to begin to drop. Therefore, the control current of the proportional relief valve is adaptively adjusted by the pressure compensation mechanism to restore the real-time pressure to the target pressing pressure. That is, by increasing the current, the opening pressure setting value of the proportional relief valve is increased, the valve port is closed smaller, and more of the hydraulic oil output by the gear pump is forced into the main oil cylinder instead of overflowing back to the oil tank. The pressure in the main oil cylinder rises accordingly, pushing the pressing plate body to recompact the material. After about 1 second, the real-time pressure returns to 49.9 MPa, which is very close to the target pressing pressure of 50 MPa. This process is repeated continuously during the pressure holding stage.

[0030] By setting a proportional overflow valve, minute changes in electrical signals are precisely converted into stable physical pressure output, thereby ensuring that the material is always subjected to optimal and constant pressure throughout the entire pressure holding period, thus ensuring a low cake residual oil rate.

[0031] Specifically, the current response unit includes a current calculation subunit and a response subunit; The current calculation subunit is used to calculate the control current adjustment value based on the PID control algorithm and the real-time pressure decay value; The response subunit is used to adjust the control current of the proportional relief valve to the control current adjustment value.

[0032] In this embodiment, the initial setting value of the control current is 400mA. The proportional relief valve maintains this specific current value to preserve the pressure. The PID control algorithm is an intelligent method that calculates the optimal control command by comprehensively considering three information: the magnitude of the current error (P), the accumulation of past errors (I), and the trend of future error changes (D). This allows a physical quantity to be maintained at the target value quickly, accurately, and stably. The control cycle is Δt = 0.1 seconds, meaning it calculates and outputs once every 0.1 seconds. The output term, i.e., the amount of current to be increased, is P + I + D. The P term is used to correct the deviation; the larger the error, the larger the output of this term. P = proportional gain × real-time pressure. Force attenuation value, proportional gain = 30 (mA / MPa); The I term characterizes the accumulation of error, i.e., the sum of errors over a period of time. I term = gain integral × cumulative error, cumulative error = average error × time, gain integral = 1.2 (mA / MPa·s); The D term measures the rate of error change. D term = differential gain × rate of change of error, rate of change of error = [current error - previous error] / time, differential gain = 5 (mA·s / MPa); In the PID formula, the D term is negative. Since the error is increasing, the rate of change is positive. If the output of the D term is positive, it means that it should suppress this increasing trend. Therefore, when the error is... When the pressure increases rapidly, option D applies a counter-force to try to slow the system down and prevent it from overshooting when the pressure rises again. For example, if the real-time pressure decay value in the pressing chamber is monitored to be 50.0 - 49.2 = 0.8 MPa, and the pressure has been slightly lower than the target for the previous 10 control cycles with an average error of about 0.1 MPa, and the pressure was 49.3 MPa 0.1 seconds ago, then the time is 10 × 0.1 s = 1 s, the cumulative error is 0.1 MPa × 1 s = 0.1 MPa·s, option I = 1.2 (mA / MPa·s) × 0.1 MPa·s = 1.2 mA; option P = 0.8 MPa × 30 (mA / MPa) = 24 mA; the previous moment... Error = 50.0 - 49.3 = 0.7 MPa, error change rate = (0.8 - 0.7) MPa / 0.1s = 1.0 MPa / s, D term = 5 (mA·s / MPa) × 1.0 MPa / s = 5 mA; output = 24 mA + 1.2 mA - 5 mA = +19.12 mA, control current adjustment value is +19.12 mA, the output current is increased by 19.1 mA based on the previous value, that is, the current needs to be fine-tuned to 419.1 mA to compensate. Therefore, in response to the real-time pressure decay value of 0.8 MPa, the response subunit increases the control current of the proportional relief valve from 400 mA to 419.1 mA.

[0033] See Figure 4 As shown, it is a schematic diagram of the controller structure according to an embodiment of the present invention; Specifically, the controller includes an oil extraction rate analysis unit, a gap monitoring unit, a pressing state analysis unit, and a pressure change analysis unit; The oil output rate analysis unit is used to determine the oil output efficiency based on the oil output rate change curve, and obtain a first determination result and a second determination result. The pressing status analysis unit is used to determine whether a pressing abnormality has occurred based on the judgment result and the current stage of the pressing process. The gap monitoring unit is used to respond to the occurrence of pressing abnormalities, obtain the real-time gap distance between the pressing ring and the pressing plate, and determine whether material leakage has occurred based on the comparison result of the real-time gap distance and the standard gap distance. The pressure change analysis unit is used to obtain the pressure fluctuation factor within a preset monitoring period in response to the real-time gap distance being less than or equal to the standard gap distance, so as to temporarily depressurize the pressing chamber or adjust the pressurization rate of the next pressing process based on the pressure fluctuation factor.

[0034] Specifically, the oil output rate analysis unit obtains the real-time slope of the oil output rate change curve for determination: If the real-time slope is less than the standard slope, the first judgment result is obtained; If the real-time slope is greater than or equal to the standard slope, a second determination result is obtained.

[0035] In the pressing process of this embodiment, as the material is gradually compacted, the resistance to oil outflow increases, and the oil extraction rate will show a steady and continuous downward trend, exhibiting a relatively stable slope value. Therefore, by comparing the real-time slope with the standard slope, if the real-time slope is less than the standard slope, it indicates that the oil extraction rate is decreasing too quickly, exceeding the normal range. In this case, it may be due to the oil extraction rate naturally and rapidly decreasing from a high point just entering the holding pressure stage, or it may be due to leakage or blockage causing abnormal pressing, resulting in the oil extraction rate decreasing too quickly. If the real-time slope is greater than or equal to the standard slope, it indicates that the change in oil extraction rate is within the expected range, that is, the pressing state is judged to be normal, and monitoring continues.

[0036] The standard slope is determined in advance based on the pressing test. By plotting the curve of oil extraction rate changing with time, the curve segment corresponding to the period from the end of the pressurization stage to the middle of the holding stage is obtained. The average change in oil extraction rate per unit time corresponding to the curve segment is calculated as the standard slope. In this embodiment, the standard slope is set to -1.5 kg / min². Multiple tests can also be conducted under the same pressing parameters. If the real-time slope is monitored to be greater than or equal to the standard slope too frequently, the standard slope is increased to -1.2 kg / min². If it is found that the response to obvious oil extraction problems is sluggish, the standard slope is decreased to -1.8 kg / min².

[0037] Specifically, the pressing state analysis unit includes a pressing state judgment unit and a pressing process analysis unit; The pressing status determination unit responds to the first determination result and determines that the pressing status is normal, and continues monitoring. The pressing process analysis unit responds to the second determination result and determines the real-time pressing pressure according to the standard pressing pressure range in order to analyze the current stage of the pressing process and thus determine whether a pressing abnormality has occurred. This embodiment analyzes the current stage of the pressing process, that is, determines the real-time pressing pressure based on the standard pressing pressure range: If the real-time pressing pressure is within the standard pressing pressure range, the current pressing process transitions from the pressurization stage to the pressure holding stage. The real-time oil output rate is determined based on the pressure holding termination rate, and the pressure holding termination node is determined based on the determination result. If the real-time pressing pressure is not within the standard pressing pressure range, and the current pressing stage has not transitioned to the pressure holding stage, a pressing abnormality will occur. In this embodiment, the standard pressing pressure range is the set allowable fluctuation range of the pressing pressure. If the real-time pressing pressure is within the standard pressing pressure range, it indicates that the pressure is up to standard. At this time, the oil extraction rate drops rapidly. This is because the oil extraction rate naturally and rapidly decreases from a high point when entering the holding pressure stage. That is, at the end of the pressurization stage, the pressure reaches its peak, and a large amount of free oil and surface oil in the material are instantly and rapidly squeezed out, resulting in the oil extraction rate reaching its peak. After entering the holding pressure stage, these easily squeezed oils have basically flowed out, and it is necessary to start squeezing deeper, intracellular oils. The flow resistance increases, so the oil extraction rate will naturally and rapidly decrease from a high point. Moreover, the pressure compensation mechanism operates effectively, so that the pressure compensation responds in a timely manner, reducing the pressing pressure. The pressure is maintained within the standard range. If the real-time pressing pressure is outside the standard pressing pressure range, it indicates leakage or blockage, resulting in low pressure and slow oil output. In this case, the real-time gap between the pressing ring and the pressing plate is analyzed to accurately determine the cause of the fault. The standard pressing pressure range is set within the range of [target pressing pressure - α, target pressing pressure + α], where α = 0.5 MPa. The pressure holding termination rate is set within the range of 0.005 kg / min to 0.01 kg / min, preferably 0.005 kg / min. The pressure holding termination rate is determined based on the real-time oil output rate. If the real-time oil output rate is less than or equal to the pressure holding termination rate, the pressure holding stage is terminated and the pressing ends. If the real-time oil output rate is greater than or equal to the pressure holding termination rate, monitoring continues.

[0038] Specifically, the pressure change analysis unit includes a pressure curve plotting unit, a pressure curve analysis unit, and a pressure factor calculation unit; The pressure curve plotting unit plots the real-time pressing pressure change curves corresponding to each collection point over time, thus obtaining the pressing pressure change curves. The pressure curve analysis unit is used to acquire collection points in the pressing pressure change curve that do not fall within the standard fluctuation range of pressing pressure, and these points are marked as abnormal fluctuation points. The pressure factor calculation unit is used to calculate the pressure fluctuation factor based on the abnormal fluctuation point. Among them, the pressure fluctuation factor is the percentage of abnormal fluctuation points out of the total number of data collection points.

[0039] Specifically, the parameter adjustment mechanism includes a first adjustment unit, a second adjustment unit, and a third adjustment unit; The first adjustment unit responds to the real-time gap distance being greater than the standard gap distance by increasing the pressurization rate of the next pressing process to the first corrected pressurization rate; The second adjustment unit, in response to a pressure fluctuation factor exceeding a pressure fluctuation threshold, reduces the pressurization rate of the next pressing process to a second corrected pressurization rate. The third adjustment unit responds to the pressure fluctuation factor being less than or equal to the pressure fluctuation threshold by increasing the pressurization rate of the next pressing process to the third corrected pressurization rate.

[0040] First corrected press rate = current press rate × β1 × [1 + K1 × (target cake residual oil rate - actual cake residual oil rate)]; β1 = 1.15, K1 = 0.04; Second modified pressurization rate = current pressurization rate × β2 × [1 + K2 × (target cake residual oil rate - actual cake residual oil rate)]; β2 = 0.75, K2 = 0.05; The third corrected pressing rate = current pressing rate × β3 × [1 + K3 × (target cake residual oil rate - actual cake residual oil rate)]; β3 = 1.08, K3 = 0.03; In this embodiment, the target cake residual oil rate is 19.5%. The standard gap distance represents the maximum allowable gap value that must be maintained between the pressing ring and the pressing plate to ensure normal pressing function during the pressing process. The set value is related to the type of pulp. The gap can effectively prevent pulp leakage, and at the same time, it provides a safety margin for the thermal expansion of the pressing ring and manufacturing tolerances, avoiding wear or jamming of metal parts due to excessively small gaps. The standard gap distance for walnut pulp is set to 0.5mm. When the real-time gap distance is determined to be less than or equal to the standard gap distance, the fault is determined to be blockage. Then, the pressure fluctuation characteristics are analyzed by introducing a pressure fluctuation factor to further analyze whether the blockage is caused by structural instability or insufficient compression. If the real-time gap distance is less than or equal to the standard gap distance, the fault is determined to be blockage. When the distance exceeds the standard gap, the fault is determined to be leakage. This is because the pressurization rate is too slow, causing the high-pressure slurry to be squeezed out preferentially through the low-resistance path, i.e., the gap between the pressing ring and the pressing platen >0.5mm. At this time, hydraulic energy is consumed in material extrusion rather than oil separation, and effective pressing pressure cannot be established. Therefore, the pressurization rate of the next pressing needs to be increased. For example, if the current rate is 3.0MPa / min and the actual residual oil rate is 22.0%, then the first corrected pressurization rate = 3.0 × 1.15 × [1 + 0.04 × (19.5% - 22.0%)] = 3.45 × [1 + 0.04 × (-2.5)] = 3.45 × [1 - 0.1] = 3.45 × 0.9 = 3.105 MPa / min; the pressure fluctuation threshold is set to 15%. The pressure fluctuation factor characterizes the stability of pressure control during the pressing process. The larger the value, the more severe the pressure fluctuation and the less stable the control. When the pressure fluctuation factor is determined to be greater than the pressure fluctuation threshold, it indicates that the internal structure of the material is unstable, that is, the structural instability causes blockage. This is because rapid pressure increase causes the surface of the material to be compacted instantaneously, forming a hard shell that hinders the flow of internal oil. Therefore, by performing a brief pressure relief operation, the permeability of the compressed material is restored, and the pressure increase rate of the next pressing process is reduced to optimize the pressure increase rate to adapt to the process of different batches. For example, if the current rate is 3.0 MPa / min and the actual residual oil rate is 22.0%, then the second corrected pressure increase rate = 3.0 × 0.75 × [1 + 0.05 × (19.5% - 22.0%)] = 2.25 × [1 + 0.05 × (-2.5)] = 2.25 × [1 - 0.125] = 2.25 × 0.875 = 1.97 MPa / min; brief pressure relief operation involves reducing the pressure to 30 MPa and maintaining it for 5-10 seconds; when the pressure fluctuation factor is less than or equal to the pressure fluctuation threshold, it indicates that the pressure increase is too slow, causing the material to accumulate uniformly but loosely, lacking the kinetic energy to overcome flow resistance. That is, the pressure is stable but cannot rise effectively, and the material is in an elastic deformation rather than plastic flow state. Therefore, the pressure increase rate is slightly increased to increase the energy density and overcome the flow threshold; this achieves accurate diagnosis from pressure anomalies to specific fault types, enabling the equipment to automatically adapt to the characteristic fluctuations of different batches of material, improving the consistency of production quality, and ensuring the fully automatic and intelligent operation of the hydraulic oil press; the corrected pressure increase rate is limited to the range of 1.5-5.0 MPa / min. Specifically, the parameter adjustment mechanism also includes a correction parameter calculation unit. The correction parameter calculation unit is used to calculate the pressurization rate for the next pressing process based on the actual cake residual oil rate.

[0041] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. An Internet of Things based temperature controlled hydraulic oil press adaptive pressure compensation control system, characterized in that, The walnut juice extraction device comprises a pressing mechanism, an oil monitoring mechanism, a pressure compensation mechanism and a controller. The pressing mechanism is configured to apply a preset pushing pressure to each pressing cavity during a pressure increasing stage. The oil monitoring mechanism is arranged on an oil receiving groove and configured to calculate a real-time oil discharge rate of the walnut slurry and draw an oil discharge rate change curve based on the real-time oil discharge rate. The pressure compensation mechanism is connected to the pressing mechanism and configured to compensate for pressure decay in the pressing cavity during a pressure maintaining stage based on a current signal of a proportional overflow valve. The controller is connected to the pressing mechanism, the oil monitoring mechanism and the pressure compensation mechanism respectively and configured to determine whether the current pressing process is transferred from the pressure increasing stage to the pressure maintaining stage based on the oil discharge rate change curve and analyze a pressure change trend in each pressing cavity based on a real-time gap distance to obtain a pressure fluctuation factor. The parameter adjustment mechanism is connected to the controller and configured to adjust a pressure increasing rate of the next pressing process based on a comparison result of the pressure fluctuation factor and a pressure fluctuation threshold.

2. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 1 wherein, The oil monitoring mechanism comprises a weighing unit and a calculation unit. The weighing unit is configured to obtain a cumulative oil mass in the oil receiving groove. The calculation unit is configured to calculate the real-time oil discharge rate based on the cumulative oil mass. The real-time oil discharge rate is a product of an incremental amount of the cumulative oil mass and a sampling time interval, and the incremental amount of the cumulative oil mass is a difference between the cumulative oil mass at a current time and the cumulative oil mass at a previous time.

3. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 1 wherein, The pressure compensation mechanism comprises a pressure deviation monitoring unit and a current response unit. The pressure deviation monitoring unit is configured to calculate a real-time pressure decay value in the pressing cavity. The current response unit is configured to obtain a control current adjustment value based on a PID control algorithm in response to the real-time pressure decay value.

4. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 3, wherein, The current response unit comprises a current calculation subunit and a response subunit. The current calculation subunit is configured to calculate the control current adjustment value based on the PID control algorithm and the real-time pressure decay value. The response subunit is configured to adjust a control current of the proportional overflow valve to the control current adjustment value.

5. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 1 wherein, The controller comprises an oil discharge rate analysis unit, a gap monitoring unit, a pressing state analysis unit and a pressure change analysis unit. The oil discharge rate analysis unit is configured to determine an oil discharge efficiency based on the oil discharge rate change curve to obtain a first determination result and a second determination result. The pressing state analysis unit is configured to determine whether a pressing abnormality occurs based on the determination result and a stage of the current pressing process. The gap monitoring unit is configured to obtain a real-time gap distance between a pressing ring and a pressing disc body in response to the pressing abnormality, and determine whether a material leakage occurs based on a comparison result of the real-time gap distance and a standard gap distance. The pressure change analysis unit is configured to obtain the pressure fluctuation factor within a preset monitoring period in response to the real-time gap distance being less than or equal to the standard gap distance, and adjust a pressure increasing rate of the next pressing process or temporarily release pressure of the pressing cavity based on the pressure fluctuation factor.

6. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 5, wherein, The oil discharge rate analysis unit obtains a real-time slope of the oil discharge rate change curve to determine the first determination result or the second determination result. If the real-time slope is less than a standard slope, the first determination result is obtained. If the real-time slope is greater than or equal to the standard slope, the second determination result is obtained.

7. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 5, wherein, The pressing state analysis unit comprises a pressing state judging unit and a pressing process analysis unit; The pressing state judging unit judges that the pressing state is normal and continues to monitor in response to the first determination result; The pressing process analysis unit determines the real-time pressing pressure according to the standard pressing pressure range in response to the second determination result, analyzes the stage of the current pressing process, and further determines whether the pressing abnormality occurs.

8. The IoT based temperature controlled hydraulic oil press adaptive pressure compensation control system as claimed in claim 5, wherein, The pressure change analysis unit comprises a pressure curve drawing unit, a pressure curve analysis unit, and a pressure factor calculation unit; The pressure curve drawing unit draws the change curve of the real-time pressing pressure corresponding to each collection point with time to obtain the pressing pressure change curve; The pressure curve analysis unit is used to obtain the collection points in the pressing pressure change curve that do not fall into the standard fluctuation pressing pressure range and mark them as abnormal fluctuation points; The pressure factor calculation unit is used to calculate the pressure fluctuation factor based on the abnormal fluctuation points; The pressure fluctuation factor is the percentage of abnormal fluctuation points in total collection points.

9. The IoT-based temperature-controlled hydraulic oil press adaptive pressure compensation control system of claim 1, wherein, The parameter adjustment mechanism comprises a first adjustment unit, a second adjustment unit, and a third adjustment unit; The first adjustment unit reduces the pressure increasing rate of the next pressing process to the first corrected pressure increasing rate in response to the real-time gap distance being greater than the standard gap distance; The second adjustment unit increases the pressure increasing rate of the next pressing process to the second corrected pressure increasing rate in response to the pressure fluctuation factor being greater than the pressure fluctuation threshold; The third adjustment unit increases the pressure increasing rate of the next pressing process to the third corrected pressure increasing rate in response to the pressure fluctuation factor being less than or equal to the pressure fluctuation threshold.

10. The IoT-based temperature-controlled hydraulic oil press adaptive pressure compensation control system of claim 9, wherein, The parameter adjustment mechanism further comprises a correction parameter calculation unit; The correction parameter calculation unit is used to calculate the pressure increasing rate of the next pressing process according to the actual cake residual oil rate.

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