Research On Automatic Measurement System Of Liquid Flowmeter

Liquid flowmeter detection system is an important platform for verifying flowmeter performance indicators.Liquid flowmeters used in theChuanqing drilling Changqing downhole operation company have been inspected by handtraditionallybecause of the high cost of calibration/testing and having no verification platform,which does requires the operator to have a strong sense of responsibility and rich experience in the instrument.Even if the instrument staff meets the above conditions,the The disadvantage of taking a long time to measure and calibrate a single flowmeter,large workload,and low traceability accuracy cannot be eliminated.And so,Chuanqing company needs to establish a flowmeter inspection platform to ensure reliable calibration and traceability of liquids,and have a relatively high efficiency,which is important for instrument inspection work.In view of a survey of flowmeters used by the company and the development status of flow standard device at home and abroad,an Efficient Combination water flow rate standard facility is researched and designed in this Thesis.With the nature of high efficiency,small cost and high degree automation,this Facility is able to calibrate or test different varieties velocity type flow meters.The system adopts the high-efficiency detection method of the hybrid application of the static mass method and the standard table method,and realizes the process control of the entire detection system based on the s7-300 Siemens PLC,achieving the goal of highly efficient and reliable detection of the flowmeter.Moreover,the scale of the weighing part is reduced on the basis of not reducing the detection accuracy,the construction cost of the detection system can be significantly reduced,and the key technologies in the detection system,such as regulation of flow and stability of flow,are designed.Specially,using the principle of multi-period synchronous measurement,an error different from the traditional pulse insertion method such as dual-timing to transfer the pulse counting error to the timer is reliably solved to ±1 error of the pulse counting.It reduces the difficulty in the design of subsequent systems and ensures reliability.This subject has studied the application of frequency conversion speed regulation technology in the flow meter detection system.The author used a multi-inverter control mode to construct a variable frequency control system for flow,whichenables variable frequency control of the flow regulation process across the entire inspection/verification flow range.Then,the system mathematical model is simulated based on Matlab/Simulink,and its stability and following characteristics are quantitatively analyzed.In the end,the uncertainty of the flow detection system device is analyzed,the performance evaluation of the detection device is completed,which proves that the design scheme of the flow meter detection system is reasonable.