An automatic purification device for grinding fluid in hard grinding.

Abstract

This invention discloses an automatic purification device for hard grinding slurry, belonging to the field of grinding slurry purification technology. Specifically, it includes a pretreatment unit, a deep purification unit, an intelligent control unit, and an auxiliary system. The outlet of the pretreatment unit is connected to the inlet of the deep purification unit via a pipeline, and the outlet of the deep purification unit is connected to the inlet of the auxiliary system. The pretreatment unit includes a multi-stage sedimentation separation chamber and a magnetic adsorption iron removal module. The deep purification unit includes a high-speed centrifugal separation module and a self-cleaning precision filtration module. This invention adopts a four-stage purification structure of "multi-stage sedimentation + magnetic adsorption iron removal + high-speed centrifugation + self-cleaning precision filtration," which can efficiently remove ultrafine powder from the grinding slurry, thoroughly reduce the turbidity of the grinding slurry, effectively solve the problem of ultrafine powder residue in existing purification methods, thereby reducing the surface scratch rate of the workpiece by more than 30%, slowing down the wear rate of the grinding wheel by 2 times, significantly improving the machining accuracy of steel balls and the product qualification rate, and reducing the cost of grinding wheel replacement.

Description

Technical Field

[0001] This invention belongs to the field of grinding fluid purification technology, specifically relating to an automatic purification device for hard grinding fluid. Background Technology

[0002] In the machining of steel ball grinding wheels, grinding fluid plays a crucial role in cooling, lubrication, friction reduction, chip removal, and cleaning. Its cleanliness directly affects machining accuracy and equipment lifespan. During production, grinding fluid can be contaminated with three key impurities: metal chips, grinding wheel debris, and ultrafine powder and sludge.

[0003] Existing grinding fluid purification methods often employ single sedimentation or filter cartridge filtration. However, these methods can only remove large particulate impurities from the grinding fluid, failing to remove ultrafine powders. Residual ultrafine powders lead to increased turbidity in the grinding fluid, which in turn increases the surface scratch rate of the workpiece by more than 30%, severely impacting the machining accuracy of steel balls and the product qualification rate. Furthermore, suspended ultrafine powders exacerbate frictional wear between the grinding wheel and the steel ball, doubling the grinding wheel wear rate. This not only increases the cost of grinding wheel replacement but also necessitates frequent shutdowns for wheel changes, severely affecting production continuity.

[0004] Therefore, there is a need to provide an automatic purification device for hard grinding fluid to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides an automatic purification device for hard grinding fluid. This device effectively solves the problem of ultrafine powder residue in existing purification methods, thereby reducing the surface scratch rate of workpieces by more than 30%, slowing down the wear rate of grinding wheels by two times, significantly improving the machining accuracy of steel balls and the product qualification rate, and reducing the cost of grinding wheel replacement.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an automatic purification device for hard grinding slurry, comprising a pretreatment unit, a deep purification unit, an intelligent control unit, and an auxiliary system, wherein the outlet of the pretreatment unit is connected to the inlet of the deep purification unit via a pipeline, and the outlet of the deep purification unit is connected to the inlet of the auxiliary system.

[0007] The pretreatment unit includes a multi-stage sedimentation separation chamber and a magnetic adsorption iron removal module. The outlet of the multi-stage sedimentation separation chamber and the inlet of the magnetic adsorption iron removal module are connected by a pipeline. The deep purification unit includes a high-speed centrifugal separation module and a self-cleaning precision filtration module. The outlet of the high-speed centrifugal separation module and the inlet of the self-cleaning precision filtration module are connected by a pipeline.

[0008] Preferably, the intelligent control unit includes a PLC controller, a touch screen display, a data recording module, and a remote communication module. The PLC controller is bidirectionally connected to the touch screen display, the data recording module is electrically connected to the PLC's memory interface, and the remote communication module is electrically connected to the PLC's communication interface.

[0009] Preferably, the intelligent control unit further includes a turbidity sensor, a flow sensor, a liquid level sensor, a differential pressure sensor, and an audible and visual alarm. The turbidity sensor is fixedly installed on the pipeline between the liquid outlet of the pretreatment unit and the liquid inlet of the deep purification unit, and the signal output terminal of the turbidity sensor is electrically connected to the signal input terminal of the PLC controller. The signal output terminals of the flow sensor, liquid level sensor and differential pressure sensor are electrically connected to the signal input terminal of the PLC controller. The flow sensor is fixedly installed on the inlet pipe of the pretreatment unit, the liquid level sensor is fixedly installed inside the clean liquid tank, and the two pressure taps of the differential pressure sensor are respectively connected to the inlet side and outlet side of the self-cleaning precision filter module. The control terminal of the audible and visual alarm is electrically connected to the output terminal of the PLC controller.

[0010] Preferably, the multi-stage sedimentation separation chamber includes at least three sedimentation sub-tanks connected in series, with adjacent sedimentation sub-tanks connected by an upper overflow port or a bottom connecting pipe; wherein the inner wall of the first sedimentation sub-tank is fixedly provided with a buffer inclined plate, and the inner wall of the last sedimentation sub-tank is fixedly provided with a guide plate.

[0011] Preferably, the magnetic adsorption iron removal module includes a housing, a rotating magnetic disk assembly, and an automatic scraper. The liquid inlet of the housing is connected to the liquid outlet of the multi-stage sedimentation separation chamber through a pipeline, and the liquid outlet of the housing is connected to the liquid inlet of the deep purification unit through a pipeline. The rotating magnetic disk assembly is rotatably connected inside the housing. The magnetic disk assembly is driven to rotate by a first drive motor fixedly connected to the housing. The automatic scraper is fixedly connected inside the housing and contacts the surface of the magnetic disk assembly.

[0012] Preferably, the high-speed centrifugal separation module is a horizontal centrifuge, and at least one scraper is fixedly provided on the inner wall of the rotor of the horizontal centrifuge, and the blade of the scraper is in contact with the inner wall of the rotor of the horizontal centrifuge.

[0013] Preferably, the self-cleaning precision filter module includes a filter element, a rotating brush rod, and a second drive motor. The rotating brush rod is rotatably disposed on the outside of the filter element, and the bristles of the rotating brush rod are in contact with the outer surface of the filter element. One end of the rotating brush rod is fixedly connected to the output shaft of the second drive motor, and the control terminal of the second drive motor is electrically connected to the output terminal of the PLC control.

[0014] Preferably, the system also includes a replenishment system, which includes a replenishment tank and a replenishment pump. The outlet of the replenishment tank is connected to the inlet of the replenishment pump through a pipeline, and the outlet of the replenishment pump is connected to the inlet of the clean liquid tank. The control terminal of the replenishment pump is electrically connected to the output terminal of the PLC controller.

[0015] Preferably, it also includes a backwash valve, which is fixedly installed on the backwash liquid inlet pipe of the self-cleaning precision filter module, and the control terminal of the backwash valve is electrically connected to the control signal output terminal of the PLC.

[0016] Preferably, the auxiliary system includes an oil-water separation module and a waste heat recovery system. The inlet of the oil-water separation module is connected to the outlet of the deep purification unit through a pipeline. A coalescing separation plate is fixedly installed inside the oil-water separation module. The outlet of the oil-water separation module is connected to the inlet of the waste heat recovery system through a pipeline. The waste heat recovery system includes a heat exchanger. The hot side inlet of the heat exchanger is connected to the hot air outlet of the high-speed centrifugal separation module, the cold side inlet of the heat exchanger is connected to the liquid outlet of the oil-water separation module, and the cold side outlet of the heat exchanger is connected to the liquid inlet of the clean liquid tank.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention adopts a four-stage purification structure of "multi-stage sedimentation + magnetic adsorption iron removal + high-speed centrifugation + self-cleaning precision filtration", which can efficiently remove ultrafine powder from grinding fluid, thoroughly reduce the turbidity of grinding fluid, effectively solve the problem of ultrafine powder residue in existing purification methods, thereby reducing the scratch rate of workpiece surface by more than 30%, slowing down the wear speed of grinding wheel by 2 times, significantly improving the processing accuracy of steel balls and the product qualification rate, and reducing the cost of grinding wheel replacement.

[0018] 2. This invention integrates a PLC intelligent control unit, which, together with multiple sensors, enables fully automated monitoring and control of the purification process. It can automatically complete operations such as sedimentation, iron removal, centrifugation, filtration, self-cleaning, liquid replenishment, and alarm. The rotating magnetic disk assembly, together with the automatic scraper, the built-in scraper of the horizontal centrifuge, and the rotating brush rod outside the filter element, enables the self-cleaning of each purification module. This eliminates the need for frequent manual cleaning of impurities and replacement of filter elements, reducing maintenance workload and ensuring production continuity.

[0019] 3. This invention adds an oil-water separation module to completely remove oil stains from the grinding fluid and extend the service life of the grinding fluid; it also integrates a waste heat recovery system to use the waste heat generated by the high-speed centrifugal separation module to heat the grinding fluid, thereby realizing energy recovery, reducing energy consumption, and meeting the requirements of energy conservation and environmental protection.

[0020] 4. Equipped with a touch screen and a remote communication module, staff can view the device's operating status and adjust parameters in real time, as well as remotely monitor and manage it, facilitating timely detection and handling of faults; the data recording module can trace purification process parameters, providing a basis for subsequent maintenance and optimization, and improving the reliability and stability of the device's operation. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the medium flow direction structure of the present invention; Figure 2 This is a schematic diagram of the electrical control flow chart structure of the present invention; Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 Please see Figure 1-2 This embodiment provides the following technical solution: an automatic purification device for hard grinding slurry, comprising a pretreatment unit, a deep purification unit, and an auxiliary system. The pretreatment unit, deep purification unit, and auxiliary system are each independently installed on a frame. The pipe interfaces between each unit are equipped with quick-release connectors. The inlet of the pretreatment unit is connected to a main inlet pipe, and a total flow regulating valve is installed on the main inlet pipe. The control terminal of the total flow regulating valve is electrically connected to the control signal output terminal of the PLC controller. The processing flow rate range of the device is 200 liters / hour to 10,000 liters / hour.

[0023] The dirty grinding fluid generated during grinding first enters the pretreatment unit through the main inlet pipe. The pretreatment unit consists of a multi-stage sedimentation separation chamber and a magnetic adsorption iron removal module connected in series. The multi-stage sedimentation separation chamber includes three sedimentation sub-tanks (A, B, and C) connected in series. The upper part of the inner wall of the first sedimentation sub-tank A is fixed with a downward-sloping buffer plate to reduce the flow rate of the grinding fluid and promote the sedimentation of large grinding debris and heavy impurities. Adjacent sedimentation sub-tanks are connected by an upper overflow port (or by a bottom connecting pipe). The inner wall of the last sedimentation sub-tank C is fixed with a guide plate to guide the supernatant to flow smoothly into the inlet pipe of the magnetic adsorption iron removal module.

[0024] After undergoing multi-stage sedimentation, the grinding fluid enters the magnetic adsorption iron removal module from the outlet of sedimentation tank C. The magnetic adsorption iron removal module includes a sealed shell, inside which a rotating magnetic disk assembly (multiple permanent magnet disks are coaxially installed) is rotatably connected. The rotating magnetic disk assembly is rotatably connected to the shell via bearings. The magnetic disk assembly is driven to rotate by a first drive motor fixedly connected to the shell. The first drive motor is controlled to be turned on or off by a PLC controller. When the grinding fluid flows over the surface of the magnetic disk assembly, ferromagnetic particles are adsorbed onto the magnetic disks. An automatic scraper is fixed inside the shell. The automatic scraper is made of wear-resistant rubber and contacts the surface of the magnetic disks. When the magnetic disks rotate, the automatic scraper scrapes off the adsorbed iron filings and collects them into the slag collection tank below. The treated grinding fluid flows out from the outlet of the shell and enters the deep purification unit.

[0025] The deep purification unit includes a high-speed centrifugal separation module and a self-cleaning precision filtration module. The high-speed centrifugal separation module uses a horizontal centrifuge. The rotor of the horizontal centrifuge generates centrifugal force under high-speed rotation, which throws fine solid particles with a density greater than liquid in the grinding fluid (such as hard grinding chips and grinding wheel fragments) onto the inner wall of the rotor of the horizontal centrifuge. Two symmetrically arranged scrapers are welded to the inner wall of the rotor of the horizontal centrifuge. The scraper blades are in contact with the inner wall of the rotor of the horizontal centrifuge. An automatic slag discharge valve is set at the bottom of the horizontal centrifuge and is controlled by a PLC controller to open and close. It can periodically scrape off and discharge the accumulated solid filter residue. The grinding fluid after centrifugation flows into the self-cleaning precision filtration module from the centrifuge outlet.

[0026] The self-cleaning precision filtration module includes a cylindrical filter element, a rotating brush rod, and a second drive motor. The filter element is made of stainless steel (filtration accuracy of 5μm). The rotating brush rod is rotatably mounted on the outside of the filter element and is rotatably connected to the filter module housing via bearings. One end of the rotating brush rod is fixedly connected to the output shaft of the second drive motor via a coupling. The bristles of the rotating brush rod are made of nylon and contact the outer surface of the filter element. The filter module housing is provided with a backwash liquid inlet, and a backwash valve is installed on the backwash liquid inlet pipeline to clean the surface of the filter element during filtration or periodically to prevent clogging. The filtration accuracy of the filter element is 1~5μm, and the filtered cleaning fluid enters the auxiliary system.

[0027] The auxiliary system includes at least a clean liquid tank, which is used to store the purified grinding slurry and supply it to the grinding machine tool for recycling through the liquid outlet pipeline.

[0028] The auxiliary system also preferably includes an oil-water separation module and a waste heat recovery system. The grinding fluid from the deep purification unit first enters the oil-water separation module. The oil-water separation module is equipped with multiple sets of coalescing separation plates. The coalescing separation plates are made of polypropylene and have an oil drain port at the top and a liquid outlet at the bottom. By utilizing the density difference between oil and water and the coalescence principle, the tiny oil droplets are aggregated and floated to the top for discharge. The oil-free grinding fluid then enters the waste heat recovery system.

[0029] The core of the waste heat recovery system is a plate heat exchanger. The hot side inlet of the plate heat exchanger is connected to the hot air outlet (centrifuge exhaust port) on the high-speed centrifugal separation module, and the cold side inlet of the plate heat exchanger is connected to the liquid outlet of the oil-water separation module. The purified grinding fluid absorbs heat from the hot air in the heat exchanger, is heated up, and then sent to the clean liquid tank to realize waste heat recovery.

[0030] Example 2 like Figure 2 As shown, the intelligent control unit is based on a PLC controller (model: S7-200). The PLC controller is fixedly connected inside the control box. The touch screen (model: MT4500T) is embedded in the control box panel. The touch screen and the PLC controller have bidirectional communication connection. The data recording module (SD card or cloud database) is electrically connected to the PLC controller's memory interface, which can store operating parameters for 3 months. The remote communication module (4G / Ethernet) is electrically connected to the PLC's communication interface, supporting remote monitoring via mobile APP or computer.

[0031] The turbidity sensor (model: DS18B20) is installed on the pipeline between the outlet of the pretreatment unit and the inlet of the deep purification unit. The signal output terminal of the turbidity sensor is electrically connected to the signal input terminal of the PLC controller to monitor the turbidity of the grinding fluid before entering the deep purification in real time. When the turbidity exceeds the set value, the PLC controller determines that the pretreatment effect is insufficient, issues an audible and visual alarm, and prompts the user to clean the sedimentation tank or check the magnetic adsorption module.

[0032] The flow sensor (model: LWGY) is installed on the main inlet pipe of the pretreatment unit. The signal output terminal of the flow sensor is electrically connected to the signal input terminal of the PLC controller to monitor the inlet flow rate. When the flow rate is abnormal (too high or too low), the PLC controller can determine that the front-end liquid supply pump is faulty or the pipeline is leaking.

[0033] The liquid level sensor (model: CYW11) is installed inside the clean liquid tank. The signal output terminal of the liquid level sensor is electrically connected to the signal input terminal of the PLC controller. The liquid level sensor is either hydrostatic or float type. The PLC controller controls the start and stop of the replenishment pump according to the liquid level signal: when the liquid level is lower than the lower limit, since the control terminal of the replenishment pump is electrically connected to the output terminal of the PLC controller, the replenishment pump is started to draw fresh grinding liquid from the replenishment tank and replenish the clean liquid tank; when the liquid level reaches the upper limit, the replenishment stops.

[0034] The differential pressure sensor (model: MPX5010DP) has two pressure taps connected to the inlet and outlet sides of the self-cleaning precision filter module 22, respectively. The signal output terminal of the differential pressure sensor is electrically connected to the signal input terminal of the PLC controller. When the differential pressure reaches the set value (e.g., 0.2MPa), it indicates that the filter element is clogged. The PLC controller starts the backwashing program: closes the filter inlet valve, opens the backwashing valve, and uses the clean polishing liquid stored in the clean liquid tank to backwash the filter element. At the same time, the second drive motor drives the rotating brush rod to rotate to assist in cleaning. The flushed waste liquid is discharged into the waste liquid collection tank. After the backwashing is completed, the filtration is automatically restored.

[0035] The control terminal of the audible and visual alarm is electrically connected to the output terminal of the PLC controller. When any sensor detects an abnormality (such as excessive differential pressure, excessive turbidity, or low liquid level but faulty replenishment pump), the PLC controller triggers an audible and visual alarm and sends alarm information to the administrator through the remote communication module.

[0036] The working principle of this invention is as follows: The waste grinding fluid after hard grinding (containing large grinding debris, iron powder, oil and fine impurities) enters the first sedimentation tank of the multi-stage sedimentation separation chamber through the pipeline. The buffer plate buffers the water flow, and the large grinding debris settles at the bottom of the tank. The grinding fluid enters the second sedimentation tank through the overflow port to remove medium-sized impurities, and then enters the third sedimentation tank to remove small-sized impurities. The pretreated grinding fluid enters the magnetic adsorption iron removal module, where a rotating magnetic disk group adsorbs iron powder, and an automatic scraper scrapes the iron powder into the slag collection tank. The grinding fluid then enters a horizontal centrifuge, where the rotor rotates at high speed (3000 r / min), generating centrifugal force to separate fine impurities and oil. The scraper removes the impurities and oil, which are then discharged through an automatic slag discharge valve. After centrifugation, the grinding fluid enters the self-cleaning precision filtration module. The filter element filters out tiny impurities, and the differential pressure sensor detects the differential pressure in real time. When the differential pressure exceeds 0.1MPa, the PLC controller controls the second drive motor to start, which drives the rotating brush rod to rotate and wash the filter element. At the same time, the backwash valve is opened to backwash the filter element for 10 minutes until the differential pressure returns to normal. After deep purification, the grinding fluid enters the oil-water separation module, where the coalescing separation plate causes tiny oil droplets to coalesce and float to the surface, and then be discharged through the oil drain port. After the oil is removed, the grinding fluid enters the cold side of the plate heat exchanger and exchanges heat with the hot air (temperature about 80°C) discharged from the horizontal centrifuge. The temperature of the grinding fluid rises to 30-40°C (suitable processing temperature), and then flows into the clean fluid tank. The liquid level sensor detects the liquid level in the clean liquid tank. When the liquid level is lower than the set value (such as 1 / 3 of the clean liquid tank volume), the PLC controller controls the replenishment pump to start and replenish the clean liquid tank with new liquid. When the liquid level reaches the set value (such as 2 / 3 of the clean liquid tank volume), the replenishment pump stops. The purified and qualified grinding fluid in the clean liquid tank is transported to the hard grinding equipment through a circulation pump to complete the recycling; Throughout the process, each sensor collects data in real time, the PLC controller automatically controls the operation of each actuator, the touch screen displays the operating status, the remote communication module supports remote monitoring, the data recording module records various parameters, and if any abnormality occurs (such as excessive turbidity or abnormal flow), the audible and visual alarm will sound in time.

[0037] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automatic purification device for grinding fluid in hard grinding, characterized in that: It includes a pretreatment unit, a deep purification unit, an intelligent control unit, and an auxiliary system. The outlet of the pretreatment unit is connected to the inlet of the deep purification unit through a pipeline, and the outlet of the deep purification unit is connected to the inlet of the auxiliary system. The pretreatment unit includes a multi-stage sedimentation separation chamber and a magnetic adsorption iron removal module. The outlet of the multi-stage sedimentation separation chamber and the inlet of the magnetic adsorption iron removal module are connected by a pipeline. The deep purification unit includes a high-speed centrifugal separation module and a self-cleaning precision filtration module. The outlet of the high-speed centrifugal separation module and the inlet of the self-cleaning precision filtration module are connected by a pipeline.

2. The automatic purification device for hard grinding fluid according to claim 1, characterized in that: The intelligent control unit includes a PLC controller, a touch screen display, a data recording module, and a remote communication module. The PLC controller and the touch screen display are bidirectionally connected, the data recording module is electrically connected to the PLC's memory interface, and the remote communication module is electrically connected to the PLC's communication interface.

3. The automatic purification device for hard grinding fluid according to claim 2, characterized in that: The intelligent control unit also includes a turbidity sensor, a flow sensor, a liquid level sensor, a differential pressure sensor, and an audible and visual alarm. The turbidity sensor is fixedly installed on the pipeline between the liquid outlet of the pretreatment unit and the liquid inlet of the deep purification unit. The signal output terminal of the turbidity sensor is electrically connected to the signal input terminal of the PLC controller. The signal output terminals of the flow sensor, liquid level sensor and differential pressure sensor are electrically connected to the signal input terminal of the PLC controller. The flow sensor is fixedly installed on the inlet pipe of the pretreatment unit, the liquid level sensor is fixedly installed inside the clean liquid tank, and the two pressure taps of the differential pressure sensor are respectively connected to the inlet side and outlet side of the self-cleaning precision filter module. The control terminal of the audible and visual alarm is electrically connected to the output terminal of the PLC controller.

4. The automatic purification device for hard grinding fluid according to claim 1, characterized in that: The multi-stage sedimentation separation chamber includes at least three sedimentation sub-tanks connected in series, with adjacent sedimentation sub-tanks connected by an upper overflow port or a bottom connecting pipe; wherein the inner wall of the first sedimentation sub-tank is fixedly provided with a buffer inclined plate, and the inner wall of the last sedimentation sub-tank is fixedly provided with a guide plate.

5. The automatic purification device for hard grinding fluid according to claim 1, characterized in that: The magnetic adsorption iron removal module includes a housing, a rotating magnetic disk assembly, and an automatic scraper. The liquid inlet of the housing is connected to the liquid outlet of the multi-stage sedimentation separation chamber through a pipeline, and the liquid outlet of the housing is connected to the liquid inlet of the deep purification unit through a pipeline. The rotating magnetic disk assembly is rotatably connected inside the housing. The magnetic disk assembly is driven to rotate by a first drive motor fixedly connected to the housing. The automatic scraper is fixedly connected inside the housing and contacts the surface of the magnetic disk assembly.

6. The automatic purification device for hard grinding fluid according to claim 1, characterized in that: The high-speed centrifugal separation module is a horizontal centrifuge. At least one scraper is fixedly installed on the inner wall of the rotor of the horizontal centrifuge, and the blade of the scraper is in contact with the inner wall of the rotor of the horizontal centrifuge.

7. The automatic purification device for hard grinding fluid according to claim 3, characterized in that: The self-cleaning precision filter module includes a filter element, a rotating brush rod, and a second drive motor. The rotating brush rod is rotatably disposed on the outside of the filter element, and the bristles of the rotating brush rod are in contact with the outer surface of the filter element. One end of the rotating brush rod is fixedly connected to the output shaft of the second drive motor, and the control terminal of the second drive motor is electrically connected to the output terminal of the PLC control.

8. The automatic purification device for hard grinding fluid according to claim 3, characterized in that: It also includes a replenishment system, which includes a replenishment tank and a replenishment pump. The outlet of the replenishment tank is connected to the inlet of the replenishment pump through a pipeline. The outlet of the replenishment pump is connected to the inlet of the clean liquid tank. The control terminal of the replenishment pump is electrically connected to the output terminal of the PLC controller.

9. The automatic purification device for hard grinding fluid according to claim 2, characterized in that: It also includes a backwash valve, which is fixedly installed on the backwash liquid inlet pipe of the self-cleaning precision filter module, and the control terminal of the backwash valve is electrically connected to the control signal output terminal of the PLC.

10. The automatic purification device for hard grinding fluid according to claim 1, characterized in that: The auxiliary system includes an oil-water separation module and a waste heat recovery system. The inlet of the oil-water separation module is connected to the outlet of the deep purification unit through a pipeline. A coalescing separation plate is fixedly installed inside the oil-water separation module. The outlet of the oil-water separation module is connected to the inlet of the waste heat recovery system through a pipeline. The waste heat recovery system includes a heat exchanger. The hot side inlet of the heat exchanger is connected to the hot air outlet of the high-speed centrifugal separation module, the cold side inlet of the heat exchanger is connected to the liquid outlet of the oil-water separation module, and the cold side outlet of the heat exchanger is connected to the liquid inlet of the clean liquid tank.

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