Design And Implementation Of Constant Pressure Control System For GMP Workshop Based On Micro-Pressure Difference

Along with the increase of population base,residents’ demand for drugs is on the rise,due to the use of drugs quality and safety of many factors,including drug production,packaging environment is very important.GMP workshop cleanliness for different types of drugs production environment standards are different,so it is particularly important to control the pharmaceutical clean room environment.The common GMP workshop control mode adopts two air supply and exhaust modes to control the pressure differential gradient,sets the pressure differential of the core pharmaceutical clean room to the highest,in order to reduce the entry of unclean air in the adjacent room,and then removes the suspended particulate matter in the clean room through internal circulation filtration,although these two methods are relatively simple to achieve.But in the use process,the new air unit is required to run full load all the time,increased energy consumption to a certain extent,is not in line with the strategic goal of our country energy-saving and emission reduction.The constant pressure control system based on micro-differential GMP workshop studied in this subject aims to control constant pressure by means of variable feed and variable discharge.In view of the above background,the constant pressure control system based on micro-differential GMP workshop is mainly for the control of micro-differential constant pressure in the clean room during the pharmaceutical process,and the centralized monitoring and display of system parameters such as pressure difference,air volume,temperature and humidity,PM2.5/10,ozone and filter pressure difference.The overall scheme of the system is designed by the main control unit,pressure difference detection unit,wind speed detection unit,environmental parameter acquisition unit,air valve control unit,human-computer interaction unit and wireless data transmission unit.Based on the differential pressure gradient of constant pressure control system in clean room of micro-differential GMP workshop,the diffused silicon differential pressure sensor which is more stable in low range environment is selected by comparison.The system wind speed detection unit adopts differential pressure method for detection.The environmental parameters are collected using RS485 communication protocol.At the same time,the analog quantity is used to control the air valve actuator.In order to ensure the accuracy of the differential pressure detection of the system,the first-order hysteresis filtering algorithm was used to calibrate the differential pressure data collected by the system,and the least square power index fitting calculation model was used to fit the measured data of the system.The optimal fitting calculation model between the differential pressure and the wind speed was obtained to ensure the accuracy of the wind speed detection of the system.At the same time,the traditional PID algorithm is further improved in the system control,and the PID algorithm is proposed to optimize the particle swarm optimization(particle swarm optimization,PSO)to quickly and accurately adjust the system differential pressure air valve actuator,which ensures the timely and accurate constant pressure control system in the workshop based on the micro-differential GMP.Based on the investigation of clean room control system at home and abroad,aiming at the problems of low pressure difference range(± 30 Pa),constant pressure control and low energy consumption required in the production process of pharmaceutical clean room,combined with the professional knowledge and internship experience learned in this major,actively respond to the national call for intelligent manufacturing and energy conservation and emission reduction targets,using differential pressure detection technology,To quickly complete the detection and control of the constant pressure difference required in the process of pharmaceutical clean room and the monitoring of other environmental parameters in pharmaceutical clean room.In order to verify the performance indicators of the system,different test schemes are designed for the accuracy,repeatability and stability of the system testing involved in the process of pharmaceutical clean room.At the same time,in view of the slow speed and low accuracy of the air valve actuator adjustment process,PSO-PID algorithm is introduced to optimize the PID controller by particle swarm optimization,improve the speed and accuracy of the air valve actuator adjustment process,and make the overall performance of the system more stable and practical.The constant pressure control mode of variable supply and variable discharge is adopted to reduce the fresh air volume of fresh air unit,which can effectively avoid excessive waste of energy consumption.