Automatic matching grinding process and system for flat gate valve plate and valve seat

Abstract

The present application relates to the technical fields of flat gate valve, and discloses a kind of flat gate valve valve plate valve seat automatic matching grinding process and system, comprising the following steps: pretreatment, selecting the valve plate and valve seat of flat gate valve, the material of valve plate and valve seat is stainless steel or alloy steel, and it is degreased, cleaned and dried;Matching grinding fluid preparation, matching grinding fluid is prepared;In the present application, automatic matching grinding system is controlled by PLC controller by integrating multi-axis industrial robot, high-precision matching grinding disc and multidimensional sensor group, can real-time control the contact pressure between valve plate and valve seat and relative motion trajectory, ensure that matching grinding force is evenly distributed on sealing surface, motion trajectory is strictly executed according to preset path, avoid the pressure uneven and trajectory deviation caused by artificial operation uncertainty, ensure the high-precision coincidence of valve plate and valve seat sealing surface, improve the sealing reliability of flat gate valve.

Description

Technical Field

[0001] This invention relates to the field of flat gate valve technology, specifically to an automatic grinding process and system for flat gate valve plates and seats. Background Technology

[0002] A flat gate valve is a sliding valve with a parallel gate as the closing element. The closing element can be a single gate or a double gate with a spreading mechanism. The pressing force of the gate against the valve seat is controlled by the medium pressure acting on the floating gate or floating valve seat.

[0003] Currently, in the grinding process of the valve plate and valve seat of a flat gate valve, the traditional grinding process mainly relies on the experience of the operator for manual grinding, which cannot accurately control the contact pressure and relative movement trajectory between the valve plate and valve seat in real time. When the grinding pressure is uneven or the movement trajectory deviates, it will lead to insufficient fit between the sealing surfaces of the valve plate and valve seat, affecting the sealing performance of the gate valve and causing media leakage.

[0004] Therefore, an automatic grinding process and system for flat gate valve plates and seats is proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an automatic matching and grinding process and system for the valve plate and seat of a flat gate valve. The automatic matching and grinding process for the valve plate and seat of a flat gate valve provided by this invention solves the problem mentioned in the background technology of insufficient fit between the valve plate and the valve seat sealing surfaces, which affects the sealing performance of the gate valve and causes media leakage.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an automatic grinding process and system for the valve plate and seat of a flat gate valve, comprising the following steps:

[0007] Step 1: Pretreatment. Select the valve plate and valve seat of the flat gate valve. The valve plate and valve seat are made of stainless steel or alloy steel. Degrease, clean and dry them.

[0008] Step 2: Preparation of grinding fluid. The grinding fluid is prepared from the following raw materials in parts by weight: 40-60 parts diamond abrasive, 20-30 parts alumina abrasive, 10-15 parts chemical activator, 5-10 parts dispersant, and 100-150 parts deionized water.

[0009] Step 3: Automatic grinding process. The pre-treated valve plate and valve seat are installed on the automatic grinding equipment. The grinding parameters are adjusted by the control system, and the grinding fluid is applied for grinding. The grinding parameters include pressure, speed and time.

[0010] Step 4: Post-processing. The valve plate and valve seat after grinding are ultrasonically cleaned, dried and surface inspected to obtain a valve plate and valve seat assembly with high matching degree.

[0011] In step three, the automatic grinding equipment includes a multi-axis robot, a grinding disc, a liquid supply system, and a sensor system. Grinding is carried out in a closed environment with the temperature controlled at 20-30℃ and the humidity controlled at 40-60%.

[0012] Preferably, the pretreatment in step one includes the following steps: immersing the valve plate and valve seat in a stainless steel tank containing degreasing solution for 1-2 hours at room temperature. During the immersion process, an ultrasonic generator is used to assist in cleaning at a frequency of 40-60kHz. After immersion, the valve plate and valve seat are removed, rinsed with deionized water for 10-15 minutes, and then placed in an oven to dry at 60-80℃ for 1-2 hours.

[0013] Preferably, the degreasing solution is composed of sodium hydroxide, surfactant and deionized water, with a mass ratio of sodium hydroxide, surfactant and deionized water of 1:0.5:10, a sodium hydroxide concentration of 5%-10%, and the surfactant is either sodium dodecylbenzene sulfonate or fatty alcohol polyoxyethylene ether.

[0014] Preferably, the preparation of the grinding fluid in step two includes the following steps: adding diamond abrasive and alumina abrasive to a high-speed stirring device, controlling the temperature at 25-35℃, stirring at 500-800 r / min for 20-30 minutes, adding chemical activator and dispersant, continuing to stir for 15-20 minutes, finally adding deionized water, increasing the speed to 1000-1500 r / min, stirring for 30-40 minutes to obtain a uniform grinding fluid.

[0015] Preferably, the chemical activator is prepared by the following method: citric acid, oxalic acid and corrosion inhibitor are selected, and the citric acid, oxalic acid and corrosion inhibitor are mixed in a mass ratio of 3:2:1, added to a reaction vessel, and stirred at 50-70°C for 1-2 hours to obtain the chemical activator. The corrosion inhibitor is either benzotriazole or sodium molybdate.

[0016] Preferably, in the preparation of the grinding fluid, the dispersant is added in batches: first, 60%-70% of the total amount of dispersant is added together with the diamond abrasive and alumina abrasive to the high-speed stirring equipment for the first stage of stirring; after adding deionized water, the remaining 30%-40% of the dispersant is added uniformly while increasing the speed to 1000-1500 r / min, and the total stirring time is 30-40 minutes.

[0017] Preferably, the automatic grinding process in step three includes the following steps: fixing the valve plate on the grinding disc, holding the valve seat by a multi-axis robot, applying the grinding fluid, starting the grinding disc to rotate at 100-200 r / min, and simultaneously controlling the valve seat to contact the valve plate with a pressure of 5-10 N. The grinding time is 30-60 minutes. During the grinding process, the surface roughness is monitored in real time by a sensor system, and the adjustment parameters are fed back.

[0018] Preferably, the sensor system includes a laser displacement sensor and a temperature sensor. The laser displacement sensor is used to measure the valve plate-valve seat gap with an accuracy of 0.1 μm, and the temperature sensor is used to monitor the temperature of the grinding interface with a control range of 20-30℃.

[0019] Preferably, the post-processing in step four includes the following steps: placing the polished valve plate and valve seat assembly into an ultrasonic cleaner, cleaning it with a mixture of acetone and ethanol for 10-15 minutes, then drying it at 50-60℃ for 30 minutes, and finally using a coordinate measuring machine to inspect the surface contour to ensure that the flatness error is less than 0.01mm.

[0020] Preferably, the system includes a pretreatment module, a grinding fluid preparation module, an automatic grinding fluid preparation module, and a posttreatment module;

[0021] The pretreatment module includes a degreasing tank, an ultrasonic cleaner, and a drying oven;

[0022] The grinding fluid preparation module includes a mixing tank, a stirrer, and a temperature control system;

[0023] The automatic grinding module includes a multi-axis robot, a grinding disc, a liquid supply pump, a sensor group, and a PLC controller;

[0024] The post-processing module includes an ultrasonic cleaner, an oven, and testing instruments;

[0025] The PLC controller connects to the sensor array, robot, and grinding disc to achieve closed-loop control.

[0026] Compared with the prior art, the present invention provides an automatic grinding process and system for the valve plate and seat of a flat gate valve, which has the following beneficial effects:

[0027] 1. In this invention, the automatic grinding system integrates a multi-axis industrial robot, a high-precision grinding disc, and a multi-dimensional sensor group, and is centrally closed-loop controlled by a PLC controller. It can adjust the contact pressure and relative motion trajectory between the valve plate and the valve seat in real time, ensuring that the grinding force is evenly distributed on the sealing surface and that the motion trajectory is strictly executed according to the preset path. This avoids pressure unevenness and trajectory deviation caused by the uncertainty of manual operation, ensures high-precision matching between the valve plate and the valve seat sealing surface, and improves the sealing reliability of the flat gate valve.

[0028] 2. In this invention, the special grinding fluid used in the automatic grinding process contains a chemical activator that can undergo a mild micro-chemical reaction with the metal surface of the valve plate and valve seat during the grinding process. This softens the microscopic protrusions on the surface of the material, reduces its deformation resistance, and produces a synergistic effect with the mechanical micro-cutting action of diamond and alumina hard abrasives. This achieves the synergy between chemical activation and mechanical grinding, thereby reducing the surface residual stress during the grinding process while ensuring material removal efficiency. This results in a sealing mating surface with better micro-geometry and higher activity, laying the foundation for improving the valve sealing performance.

[0029] 3. In this invention, the sensor system monitors key parameters of the grinding interface in real time, including surface roughness, gap, and temperature, and feeds the data back to the PLC controller in real time. The controller dynamically adjusts the grinding parameters, including pressure, rotation speed, and grinding fluid supply rate, according to a preset algorithm. This achieves online adaptive control and online quality evaluation of the grinding process, avoids quality risks caused by fluctuations in grinding fluid performance or abnormal supply, and forms an efficient and reliable quality closed-loop management system, ensuring the consistency and stability of grinding quality in mass production. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1: An automatic grinding process and system for flat gate valve plates and seats, comprising the following steps:

[0032] Step 1: Pretreatment. Select the valve plate and valve seat of the flat gate valve. The valve plate and valve seat are made of stainless steel or alloy steel. Degrease, clean and dry them.

[0033] Step 2: Preparation of grinding fluid. The grinding fluid is prepared from the following raw materials in parts by weight: 40 parts diamond abrasive, 20 parts alumina abrasive, 10 parts chemical activator, 5 parts dispersant, and 100 parts deionized water.

[0034] Step 3: Automatic grinding process. The pre-treated valve plate and valve seat are installed on the automatic grinding equipment. The grinding parameters are adjusted by the control system, and the grinding fluid is applied for grinding. The grinding parameters include pressure, speed and time.

[0035] Step 4: Post-processing. The valve plate and valve seat after grinding are ultrasonically cleaned, dried and surface inspected to obtain a valve plate and valve seat assembly with high matching degree.

[0036] In step three, the automatic grinding equipment includes a multi-axis robot, a grinding disc, a liquid supply system, and a sensor system. The grinding is carried out in a closed environment with the temperature controlled at 20°C and the humidity controlled at 40%.

[0037] The pretreatment in step one includes the following steps: immerse the valve plate and valve seat in a stainless steel tank containing degreasing solution for 1 hour at room temperature. During the immersion process, use an ultrasonic generator at a frequency of 40kHz for auxiliary cleaning. After immersion, remove the valve plate and valve seat, rinse with deionized water for 10 minutes, and then place them in an oven to dry at 60℃ for 1 hour.

[0038] The degreasing solution is composed of sodium hydroxide, surfactant and deionized water. The mass ratio of sodium hydroxide, surfactant and deionized water is 1:0.5:10. The concentration of sodium hydroxide is 5%. The surfactant is either sodium dodecylbenzene sulfonate or fatty alcohol polyoxyethylene ether.

[0039] Step 2 involves the following steps in preparing the grinding fluid: diamond abrasive and alumina abrasive are added to a high-speed mixing device, the temperature is controlled at 25°C, and the mixture is stirred at 500 r / min for 20 minutes. Then, a chemical activator and a dispersant are added, and the mixture is stirred for another 15 minutes. Finally, deionized water is added, the speed is increased to 1000 r / min, and the mixture is stirred for 30 minutes to obtain a uniform grinding fluid.

[0040] The chemical activator is prepared by the following method: Citric acid, oxalic acid and corrosion inhibitor are selected, and the citric acid, oxalic acid and corrosion inhibitor are mixed in a mass ratio of 3:2:1 and added to a reaction vessel. The mixture is stirred at 50°C for 1 hour to obtain the chemical activator. The corrosion inhibitor is either benzotriazole or sodium molybdate.

[0041] In the preparation of the grinding fluid, the dispersant is added in batches: first, 60% of the total amount of dispersant is added together with the diamond abrasive and alumina abrasive to the high-speed stirring equipment for the first stage of stirring; after adding deionized water, the remaining 30% of the dispersant is added at a uniform speed while increasing the speed to 1000 r / min, and the total stirring time is 30 minutes.

[0042] Step 3 of the automatic grinding process includes the following steps: the valve plate is fixed on the grinding disc, the valve seat is held by a multi-axis robot, after the grinding fluid is applied, the grinding disc is started to rotate at 100 r / min, and at the same time the robot controls the valve seat to contact the valve plate with a pressure of 5N. The grinding time is 30 minutes. During the grinding process, the surface roughness is monitored in real time by a sensor system, and the adjustment parameters are fed back.

[0043] The sensor system includes a laser displacement sensor and a temperature sensor. The laser displacement sensor is used to measure the valve plate-seat clearance with an accuracy of 0.1 μm, and the temperature sensor is used to monitor the temperature of the grinding interface and control it at 20 °C.

[0044] The post-processing in step four includes the following steps: the valve plate and valve seat assembly after grinding is placed in an ultrasonic cleaner and cleaned with a mixture of acetone and ethanol for 10 minutes, then dried at 50°C for 30 minutes, and finally the surface contour is inspected using a coordinate measuring machine to ensure that the flatness error is less than 0.01mm.

[0045] The pretreatment module includes a degreasing tank, an ultrasonic cleaner, and a drying oven. The degreasing tank has a volume of 50L and is made of 316L stainless steel. It is equipped with a heating element and a temperature sensor, with a temperature control accuracy of ±1℃. The ultrasonic cleaner operates at a frequency of 40kHz and has a power setting of 500W. The drying oven uses a hot air circulation system with a temperature control range of room temperature to 120℃ and adjustable air speed.

[0046] The grinding fluid preparation module includes a mixing tank, a stirrer, and a temperature control system. The mixing tank has a volume of 100L and is lined with a polytetrafluoroethylene anti-corrosion layer. The stirrer is driven by a variable frequency motor with a speed of 600r / min. The temperature control system includes a PT100 temperature sensor and a PID controller with a temperature control accuracy of ±0.5℃.

[0047] The automatic grinding module includes a multi-axis robot, a grinding disc, a liquid supply pump, a sensor group, and a PLC controller. The multi-axis robot is a six-degree-of-freedom industrial robot with a repeatability of ≤0.02mm. The grinding disc is made of cast iron with a hard chrome plated surface and has a diameter of 300mm. The liquid supply pump is a peristaltic pump with a flow rate accuracy of ±1%. The sensor group includes a laser displacement sensor and an infrared temperature sensor. The laser displacement sensor has a resolution of 0.1μm and a sampling frequency of 1kHz. The infrared temperature sensor measures a temperature of 25℃ with an accuracy of ±0.1℃.

[0048] The post-processing module includes an ultrasonic cleaner, an oven, and a coordinate measuring machine. The ultrasonic cleaner has a tank volume of 30L and adopts dual-frequency switching technology. The oven has a stainless steel inner liner and is equipped with a forced convection system. The coordinate measuring machine has a measurement accuracy of (2.5+L / 300)μm.

[0049] The PLC controller adopts a modular structure, including a CPU module, an analog input / output module, a motion control module, and a communication module. The CPU module has a processing speed of no less than 0.1ms / thousand instructions and supports EtherCAT bus communication. The motion control module can control 8 servo axes simultaneously with an interpolation cycle of less than 1ms. The communication module supports PROFIBUS-DP and Modbus-TCP industrial protocols.

[0050] The specific workflow of the system is as follows:

[0051] The pretreatment module receives the valve plate and valve seat workpiece and sequentially performs degreasing, ultrasonic cleaning and drying.

[0052] The grinding fluid preparation module automatically completes the preparation and quality testing of the grinding fluid according to the preset formula;

[0053] The automatic grinding module uses a multi-axis robot to clamp the workpiece, and the grinding disc moves along a preset trajectory, while the liquid supply system supplies grinding fluid.

[0054] The sensor group collects force, displacement, and temperature parameters in real time during the grinding process and feeds them back to the PLC controller;

[0055] The PLC controller dynamically adjusts the grinding parameters based on sensor data to achieve adaptive grinding.

[0056] The post-processing module cleans, dries, and performs precision testing on the workpieces after grinding.

[0057] All process data is automatically recorded and uploaded to the database, enabling product quality traceability.

[0058] Example 2: An automatic grinding process and system for flat gate valve plates and seats, comprising the following steps:

[0059] Step 1: Pretreatment. Select the valve plate and valve seat of the flat gate valve. The valve plate and valve seat are made of stainless steel or alloy steel. Degrease, clean and dry them.

[0060] Step 2: Preparation of grinding fluid. The grinding fluid is prepared from the following raw materials in parts by weight: 50 parts diamond abrasive, 25 parts alumina abrasive, 11 parts chemical activator, 7 parts dispersant and 120 parts deionized water.

[0061] Step 3: Automatic grinding process. The pre-treated valve plate and valve seat are installed on the automatic grinding equipment. The grinding parameters are adjusted by the control system, and the grinding fluid is applied for grinding. The grinding parameters include pressure, speed and time.

[0062] Step 4: Post-processing. The valve plate and valve seat after grinding are ultrasonically cleaned, dried and surface inspected to obtain a valve plate and valve seat assembly with high matching degree.

[0063] In step three, the automatic grinding equipment includes a multi-axis robot, a grinding disc, a liquid supply system, and a sensor system. The grinding is carried out in a closed environment with the temperature controlled at 25°C and the humidity controlled at 50%.

[0064] The pretreatment in step one includes the following steps: immerse the valve plate and valve seat in a stainless steel tank containing degreasing solution for 1.5 hours at room temperature. During the immersion process, use an ultrasonic generator at a frequency of 50kHz for auxiliary cleaning. After immersion, remove the valve plate and valve seat, rinse with deionized water for 12 minutes, and then place them in an oven to dry at 70℃ for 1.5 hours.

[0065] The degreasing solution is composed of sodium hydroxide, surfactant and deionized water. The mass ratio of sodium hydroxide, surfactant and deionized water is 1:0.5:10. The concentration of sodium hydroxide is 7%. The surfactant is either sodium dodecylbenzene sulfonate or fatty alcohol polyoxyethylene ether.

[0066] Step 2 involves the following steps in preparing the grinding fluid: diamond abrasive and alumina abrasive are added to a high-speed stirring device, the temperature is controlled at 30°C, and the mixture is stirred at 650 r / min for 25 minutes. Then, a chemical activator and a dispersant are added, and the mixture is stirred for another 17 minutes. Finally, deionized water is added, the speed is increased to 1200 r / min, and the mixture is stirred for 35 minutes to obtain a uniform grinding fluid.

[0067] The chemical activator is prepared by the following method: Citric acid, oxalic acid and corrosion inhibitor are selected, and the citric acid, oxalic acid and corrosion inhibitor are mixed in a mass ratio of 3:2:1 and added to a reaction vessel. The mixture is stirred at 60°C for 1.5 hours to obtain the chemical activator. The corrosion inhibitor is either benzotriazole or sodium molybdate.

[0068] In the preparation of the grinding fluid, the dispersant is added in batches: first, 65% of the total amount of dispersant is added together with the diamond abrasive and alumina abrasive to the high-speed stirring equipment for the first stage of stirring; after adding deionized water, the remaining 35% of the dispersant is added at a uniform speed while increasing the speed to 1200 r / min, and the total stirring time is 35 minutes.

[0069] Step 3, the automatic grinding process includes the following steps: the valve plate is fixed on the grinding disc, the valve seat is held by a multi-axis robot, after the grinding fluid is applied, the grinding disc is started to rotate at 150 r / min, and at the same time the robot controls the valve seat to contact the valve plate with a pressure of 7N. The grinding time is 45 minutes. During the grinding process, the surface roughness is monitored in real time by a sensor system, and the adjustment parameters are fed back.

[0070] The sensor system includes a laser displacement sensor and a temperature sensor. The laser displacement sensor is used to measure the valve plate-seat clearance with an accuracy of 0.1 μm, and the temperature sensor is used to monitor the temperature of the grinding interface and control it at 25°C.

[0071] The post-processing in step four includes the following steps: the valve plate and valve seat assembly after grinding is placed in an ultrasonic cleaner and cleaned with a mixture of acetone and ethanol for 12 minutes, then dried at 55°C for 30 minutes, and finally the surface contour is inspected using a coordinate measuring machine to ensure that the flatness error is less than 0.01mm.

[0072] The pretreatment module includes a degreasing tank, an ultrasonic cleaner, and a drying oven. The degreasing tank has a volume of 80L and is made of 316L stainless steel. It is equipped with a heating element and a temperature sensor, with a temperature control accuracy of ±1℃. The ultrasonic cleaner operates at a frequency of 50kHz and has a power setting of 1000W. The drying oven uses a hot air circulation system with a temperature control range of room temperature to 120℃ and adjustable air speed.

[0073] The grinding fluid preparation module includes a mixing tank, a stirrer, and a temperature control system. The mixing tank has a volume of 150L and is lined with a polytetrafluoroethylene anti-corrosion layer. The stirrer is driven by a variable frequency motor with a speed of 1200r / min. The temperature control system includes a PT100 temperature sensor and a PID controller, with a temperature control accuracy of ±0.5℃.

[0074] The automatic grinding module includes a multi-axis robot, a grinding disc, a liquid supply pump, a sensor group, and a PLC controller. The multi-axis robot is a six-degree-of-freedom industrial robot with a repeatability of ≤0.02mm. The grinding disc is made of cast iron with a hard chrome plated surface and has a diameter of 400mm. The liquid supply pump is a peristaltic pump with a flow rate accuracy of ±1%. The sensor group includes a laser displacement sensor and an infrared temperature sensor. The laser displacement sensor has a resolution of 0.1μm and a sampling frequency of 1kHz. The infrared temperature sensor measures a temperature of 28℃ with an accuracy of ±0.1℃.

[0075] The post-processing module includes an ultrasonic cleaner, an oven, and a coordinate measuring machine. The ultrasonic cleaner has a tank volume of 40L and adopts dual-frequency switching technology. The oven has a stainless steel inner liner and is equipped with a forced convection system. The coordinate measuring machine has a measurement accuracy of (2.5+L / 300)μm.

[0076] The PLC controller adopts a modular structure, including a CPU module, an analog input / output module, a motion control module, and a communication module. The CPU module has a processing speed of no less than 0.1ms / thousand instructions and supports EtherCAT bus communication. The motion control module can control 8 servo axes simultaneously with an interpolation cycle of less than 1ms. The communication module supports PROFIBUS-DP and Modbus-TCP industrial protocols.

[0077] The specific workflow of the system is as follows:

[0078] The pretreatment module receives the valve plate and valve seat workpiece and sequentially performs degreasing, ultrasonic cleaning and drying.

[0079] The grinding fluid preparation module automatically completes the preparation and quality testing of the grinding fluid according to the preset formula;

[0080] The automatic grinding module uses a multi-axis robot to clamp the workpiece, and the grinding disc moves along a preset trajectory, while the liquid supply system supplies grinding fluid.

[0081] The sensor group collects force, displacement, and temperature parameters in real time during the grinding process and feeds them back to the PLC controller;

[0082] The PLC controller dynamically adjusts the grinding parameters based on sensor data to achieve adaptive grinding.

[0083] The post-processing module cleans, dries, and performs precision testing on the workpieces after grinding.

[0084] All process data is automatically recorded and uploaded to the database, enabling product quality traceability.

[0085] Example 3: An automatic grinding process and system for flat gate valve plates and seats, comprising the following steps:

[0086] Step 1: Pretreatment. Select the valve plate and valve seat of the flat gate valve. The valve plate and valve seat are made of stainless steel or alloy steel. Degrease, clean and dry them.

[0087] Step 2: Preparation of grinding fluid. The grinding fluid is prepared from the following raw materials in parts by weight: 60 parts diamond abrasive, 30 parts alumina abrasive, 15 parts chemical activator, 10 parts dispersant and 150 parts deionized water.

[0088] Step 3: Automatic grinding process. The pre-treated valve plate and valve seat are installed on the automatic grinding equipment. The grinding parameters are adjusted by the control system, and the grinding fluid is applied for grinding. The grinding parameters include pressure, speed and time.

[0089] Step 4: Post-processing. The valve plate and valve seat after grinding are ultrasonically cleaned, dried and surface inspected to obtain a valve plate and valve seat assembly with high matching degree.

[0090] In step three, the automatic grinding equipment includes a multi-axis robot, a grinding disc, a liquid supply system, and a sensor system. The grinding is carried out in a closed environment with the temperature controlled at 30°C and the humidity controlled at 60%.

[0091] The pretreatment in step one includes the following steps: immerse the valve plate and valve seat in a stainless steel tank containing degreasing solution for 2 hours at room temperature. During the immersion process, use an ultrasonic generator at a frequency of 60kHz for auxiliary cleaning. After immersion, remove the valve plate and valve seat, rinse with deionized water for 15 minutes, and then place them in an oven to dry at 80℃ for 2 hours.

[0092] The degreasing solution is composed of sodium hydroxide, surfactant and deionized water. The mass ratio of sodium hydroxide, surfactant and deionized water is 1:0.5:10. The concentration of sodium hydroxide is 10%. The surfactant is either sodium dodecylbenzene sulfonate or fatty alcohol polyoxyethylene ether.

[0093] Step 2 involves the following steps in preparing the grinding fluid: diamond abrasive and alumina abrasive are added to a high-speed mixing device, the temperature is controlled at 35°C, and the mixture is stirred at 800 r / min for 30 minutes. Then, a chemical activator and a dispersant are added, and the mixture is stirred for another 20 minutes. Finally, deionized water is added, the speed is increased to 1500 r / min, and the mixture is stirred for 40 minutes to obtain a uniform grinding fluid.

[0094] The chemical activator is prepared by the following method: Citric acid, oxalic acid and corrosion inhibitor are selected, and the citric acid, oxalic acid and corrosion inhibitor are mixed in a mass ratio of 3:2:1 and added to a reaction vessel. The mixture is stirred at 70°C for 2 hours to obtain the chemical activator. The corrosion inhibitor is either benzotriazole or sodium molybdate.

[0095] In the preparation of the grinding fluid, the dispersant is added in batches: first, 70% of the total amount of dispersant is added together with the diamond abrasive and alumina abrasive to the high-speed stirring equipment for the first stage of stirring; after adding deionized water, the remaining 40% of the dispersant is added at a uniform speed while increasing the speed to 1500 r / min, and the total stirring time is 40 minutes.

[0096] Step 3 of the automatic grinding process includes the following steps: the valve plate is fixed on the grinding disc, the valve seat is held by a multi-axis robot, after the grinding fluid is applied, the grinding disc is started to rotate at 200 r / min, and at the same time the robot controls the valve seat to contact the valve plate with a pressure of 10N. The grinding time is 60 minutes. During the grinding process, the surface roughness is monitored in real time by a sensor system, and the adjustment parameters are fed back.

[0097] The sensor system includes a laser displacement sensor and a temperature sensor. The laser displacement sensor is used to measure the valve plate-seat clearance with an accuracy of 0.1 μm, and the temperature sensor is used to monitor the temperature of the grinding interface and control it at 30°C.

[0098] The post-processing in step four includes the following steps: the valve plate and valve seat assembly after grinding is placed in an ultrasonic cleaner and cleaned with a mixture of acetone and ethanol for 15 minutes, then dried at 60°C for 30 minutes, and finally the surface contour is inspected using a coordinate measuring machine to ensure that the flatness error is less than 0.01mm.

[0099] The pretreatment module includes a degreasing tank, an ultrasonic cleaner, and a drying oven. The degreasing tank has a volume of 100L and is made of 316L stainless steel. It is equipped with a heating element and a temperature sensor, with a temperature control accuracy of ±1℃. The ultrasonic cleaner operates at a frequency of 60kHz and has a power setting of 1000W. The drying oven uses a hot air circulation system with a temperature control range of room temperature to 120℃ and adjustable air speed.

[0100] The grinding fluid preparation module includes a mixing tank, a stirrer, and a temperature control system. The mixing tank has a volume of 200L and is lined with a polytetrafluoroethylene anti-corrosion layer. The stirrer is driven by a variable frequency motor with a speed of 1800r / min. The temperature control system includes a PT100 temperature sensor and a PID controller, with a temperature control accuracy of ±0.5℃.

[0101] The automatic grinding module includes a multi-axis robot, a grinding disc, a liquid supply pump, a sensor group, and a PLC controller. The multi-axis robot is a six-degree-of-freedom industrial robot with a repeatability of ≤0.02mm. The grinding disc is made of cast iron with a hard chrome plated surface and has a diameter of 500mm. The liquid supply pump is a peristaltic pump with a flow rate accuracy of ±1%. The sensor group includes a laser displacement sensor and an infrared temperature sensor. The laser displacement sensor has a resolution of 0.1μm and a sampling frequency of 1kHz. The infrared temperature sensor measures a temperature of 30℃ with an accuracy of ±0.1℃.

[0102] The post-processing module includes an ultrasonic cleaner, an oven, and a coordinate measuring machine. The ultrasonic cleaner has a tank volume of 50L and adopts dual-frequency switching technology. The oven has a stainless steel inner liner and is equipped with a forced convection system. The coordinate measuring machine has a measurement accuracy of (2.5+L / 300)μm.

[0103] The PLC controller adopts a modular structure, including a CPU module, an analog input / output module, a motion control module, and a communication module. The CPU module has a processing speed of no less than 0.1ms / thousand instructions and supports EtherCAT bus communication. The motion control module can control 8 servo axes simultaneously with an interpolation cycle of less than 1ms. The communication module supports PROFIBUS-DP and Modbus-TCP industrial protocols.

[0104] The specific workflow of the system is as follows:

[0105] The pretreatment module receives the valve plate and valve seat workpiece and sequentially performs degreasing, ultrasonic cleaning and drying.

[0106] The grinding fluid preparation module automatically completes the preparation and quality testing of the grinding fluid according to the preset formula;

[0107] The automatic grinding module uses a multi-axis robot to clamp the workpiece, and the grinding disc moves along a preset trajectory, while the liquid supply system supplies grinding fluid.

[0108] The sensor group collects force, displacement, and temperature parameters in real time during the grinding process and feeds them back to the PLC controller;

[0109] The PLC controller dynamically adjusts the grinding parameters based on sensor data to achieve adaptive grinding.

[0110] The post-processing module cleans, dries, and performs precision testing on the workpieces after grinding.

[0111] All process data is automatically recorded and uploaded to the database, enabling product quality traceability.

[0112] Comparative Example 1: The difference between this comparative example and Example 1 is that no chemical activator was added when preparing the grinding fluid in this comparative example.

[0113] Comparative Example 2 differs from Example 1 in that: this comparative example does not use a sensor system for real-time monitoring and feedback adjustment during automatic grinding.

[0114] Comparative Example 3 differs from Example 1 in that the valve plate and valve seat were not pre-treated in this comparative example.

[0115] Comparative Example 4 differs from Example 1 in that: no surface contour detection was performed in the post-processing stage after the grinding was completed in this comparative example.

[0116] The test data of the flat gate valve plate and valve seat assemblies prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below:

[0117] Testing items Sealing surface fit (μm) Leakage rate (mL / min) Surface roughness Ra (μm) Wear life (number of cycles) Example 1 1.2±0.1 0.0 0.45±0.05 15200±300 Example 2 1.5±0.2 0.0 0.48±0.05 14100±400 Example 3 1.3±0.1 0.0 0.46±0.05 14600±300 Comparative Example 1 5.8±0.8 12.5 0.85±0.15 5800±500 Comparative Example 2 5.0±1.0 25.6 0.82±0.20 4200±600 Comparative Example 3 4.2±0.6 8.3 0.65±0.12 6500±500 Comparative Example 4 3.5±0.5 5.1 0.55±0.08 10500±400

[0118] By comparing and analyzing the data in the table, it can be seen that the flat gate valve plate and seat assembly prepared using the processes and systems in Examples 1-3 is superior to the assembly prepared using the processes in Comparative Examples 1-4 in terms of key performance indicators. This indicates that the automatic grinding system, by integrating a multi-axis industrial robot, a high-precision grinding disc, and a multi-dimensional sensor group, and using a PLC controller for centralized closed-loop control, can adjust the contact pressure and relative motion trajectory between the valve plate and the valve seat in real time, ensuring that the grinding force is evenly distributed on the sealing surface and that the motion trajectory strictly follows the preset path. This avoids pressure unevenness and trajectory deviation caused by the uncertainty of manual operation, ensures high-precision matching of the sealing surfaces of the valve plate and the valve seat, and improves the sealing reliability of the flat gate valve. The specialized grinding fluid used in the automated grinding process contains chemical activators that undergo a gentle micro-chemical reaction with the metal surfaces of valve plates and seats during grinding. This softens microscopic protrusions on the material surface, reducing their deformation resistance. This synergistic effect with the mechanical micro-cutting action of diamond and alumina hard abrasives achieves a combined chemical activation and mechanical grinding, thus reducing residual surface stress during grinding while ensuring material removal efficiency. This results in a sealing surface with superior micro-geometry and higher activity, laying the foundation for improved valve sealing performance. A sensor system monitors key parameters of the grinding interface in real time, including surface roughness, gap, and temperature, and feeds the data back to the PLC controller. The controller dynamically adjusts grinding parameters, including pressure, speed, and grinding fluid supply rate, based on a preset algorithm. This enables online adaptive control and online quality assessment of the grinding process, avoiding quality risks caused by fluctuations in grinding fluid performance or abnormal supply. This forms an efficient and reliable closed-loop quality management system, ensuring the consistency and stability of grinding quality in mass production.

[0119] By comparing and analyzing the relevant data in the table, it can be seen that the automatic grinding process and system provided by this invention can produce valve plates and seats with high sealing accuracy, excellent sealing reliability, and ultra-long service life. This indicates that the automatic grinding process and system for flat gate valve plates and seats provided by this invention has advantages in improving product quality consistency and production efficiency, and possesses superior overall performance.

[0120] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0121] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automatic grinding process for the valve plate and seat of a flat gate valve, characterized in that: Includes the following steps: Step 1: Pre-treatment. Select the valve plate and valve seat of the flat gate valve. The valve plate and valve seat are made of stainless steel or alloy steel. Degrease, clean and dry them. Step 2: Preparation of grinding fluid. The grinding fluid is prepared from the following raw materials in parts by weight: 40-60 parts diamond abrasive, 20-30 parts alumina abrasive, 10-15 parts chemical activator, 5-10 parts dispersant, and 100-150 parts deionized water. The chemical activator is prepared by the following method: citric acid, oxalic acid and corrosion inhibitor are selected, and the citric acid, oxalic acid and corrosion inhibitor are mixed in a mass ratio of 3:2:1, added to a reaction vessel, and stirred at 50-70℃ for 1-2 hours to obtain the chemical activator. The corrosion inhibitor is either benzotriazole or sodium molybdate. The dispersant is added in batches: first, 60%-70% of the total amount of the dispersant is added together with the diamond abrasive and alumina abrasive to the high-speed mixing equipment for the first stage of mixing; after adding deionized water, the remaining 30%-40% of the dispersant is added at a uniform speed while increasing the speed to 1000-1500 r / min, and the total mixing time is 30-40 minutes. Step 3: Automatic grinding process. The pre-treated valve plate and valve seat are installed on the automatic grinding equipment. The grinding parameters are adjusted by the control system, and the grinding fluid is applied for grinding. The grinding parameters include pressure, speed and time. Step 4: Post-processing, the valve plate and valve seat after grinding are ultrasonically cleaned, dried and surface inspected to obtain a valve plate and valve seat assembly with high matching degree; In step three, the automatic grinding equipment includes a multi-axis robot, a grinding disc, a liquid supply system, and a sensor system. The grinding is carried out in a closed environment with the temperature controlled at 20-30℃ and the humidity controlled at 40-60%.

2. The automatic grinding process for the valve plate and seat of a flat gate valve according to claim 1, characterized in that: The pretreatment in step one includes the following steps: immersing the valve plate and valve seat in a stainless steel tank containing degreasing solution for 1-2 hours at room temperature. During the immersion process, an ultrasonic generator is used to assist in cleaning at a frequency of 40-60kHz. After immersion, the valve plate and valve seat are removed, rinsed with deionized water for 10-15 minutes, and then placed in an oven to dry at 60-80℃ for 1-2 hours.

3. The automatic grinding process for the valve plate and seat of a flat gate valve according to claim 2, characterized in that: The degreasing solution is composed of sodium hydroxide, surfactant and deionized water, with the mass ratio of sodium hydroxide, surfactant and deionized water being 1:0.5:

10. The concentration of sodium hydroxide is 5%-10%, and the surfactant is either sodium dodecylbenzene sulfonate or fatty alcohol polyoxyethylene ether.

4. The automatic grinding process for the valve plate and seat of a flat gate valve according to claim 1, characterized in that: The preparation of the grinding fluid in step two includes the following steps: Add diamond abrasive and alumina abrasive to a high-speed mixing device, control the temperature at 25-35℃, and stir at 500-800 r / min for 20-30 minutes. Then add chemical activator and dispersant, continue stirring for 15-20 minutes, and finally add deionized water. Increase the speed to 1000-1500 r / min and stir for 30-40 minutes to obtain a uniform grinding solution.

5. The automatic grinding process for the valve plate and seat of a flat gate valve according to claim 1, characterized in that: The automatic grinding process in step three includes the following steps: fixing the valve plate on the grinding disc, holding the valve seat by a multi-axis robot, applying the grinding fluid, starting the grinding disc to rotate at 100-200 r / min, and simultaneously controlling the valve seat to contact the valve plate with a pressure of 5-10 N. The grinding time is 30-60 minutes. During the grinding process, the surface roughness is monitored in real time by a sensor system, and the adjustment parameters are fed back.

6. The automatic grinding process for the valve plate and seat of a flat gate valve according to claim 5, characterized in that: The sensor system includes a laser displacement sensor and a temperature sensor. The laser displacement sensor is used to measure the valve plate-valve seat gap with an accuracy of 0.1 μm, and the temperature sensor is used to monitor the temperature of the grinding interface with a control range of 20-30℃.

7. The automatic grinding process for the valve plate and seat of a flat gate valve according to claim 1, characterized in that: The post-processing in step four includes the following steps: placing the polished valve plate and valve seat assembly into an ultrasonic cleaner, cleaning it with a mixture of acetone and ethanol for 10-15 minutes, then drying it at 50-60℃ for 30 minutes, and finally using a coordinate measuring machine to inspect the surface contour to ensure that the flatness error is less than 0.01mm.

8. An automatic grinding system for the valve plate and seat of a flat gate valve, used to implement the automatic grinding process for the valve plate and seat of a flat gate valve as described in any one of claims 1-7, characterized in that, The system includes a pretreatment module, a grinding fluid preparation module, an automatic grinding fluid preparation module, and a posttreatment module; The pretreatment module includes a degreasing tank, an ultrasonic cleaner, and a drying oven; The grinding fluid preparation module includes a mixing tank, a stirrer, and a temperature control system; The automatic grinding module includes a multi-axis robot, a grinding disc, a liquid supply pump, a sensor group, and a PLC controller. The post-processing module includes an ultrasonic cleaner, an oven, and testing instruments; The PLC controller is connected to the sensor group, robot, and grinding disc to achieve closed-loop control.