| Volume correction instrument is an important part of gas flow measurement in industry and commerce.Most natural gas measurement sites use gas flowmeter+volume correction instrument to measure natural gas volume.The accuracy of measurement of pulse signals from temperature sensor,pressure sensor and flowmeter by volumetric corrector is directly related to the accuracy of measuring trade of natural gas flow.The traditional calibration equipment is simple and less automatic,which cannot guarantee the reliability of calibration data of the correction instrument,thus reducing the calibration progress and working efficiency.This paper analyzes the working principle and structure of the modifier.The defects of existing devices and the requirements of calibration are analyzed and the scheme of automatic calibration system is designed.The main contents are as follows:(1)This paper expounds the importance of gas volume correction instrument calibration,introduces the existing domestic calibration equipment,and indicates the content and chapter arrangement of this subject.(2)This paper analyzes the types of correctors existing in the market,demonstrates the possibility of adopting automatic calibration,conducts in-depth analysis on the correctors that meet the requirements,and provides technical support for the establishment of the device.The method of volume correction instrument calibration is introduced.Formulate the specific content of calibration volume correction instrument according to the current national verification regulations or calibration specifications.(3)The defects of existing devices are analyzed.Establish the overall requirements of the calibration device according to the requirements of relevant verification regulations;Make overall design scheme of calibration device.Based on the existing technical development level,the main equipment frequency generator,pressure controller,constant temperature oil tank or dry measuring furnace of the calibrating device are selected and analyzed.(4)Explain the hardware design of the calibration device and briefly introduce the PLC and industrial computer.Then analyze the parameter setting and communication wiring mode of the volume correction instrument during data acquisition,and introduce the control method and control structure used in the pressure control.(5)Explain the software design,including the calibration main interface,the checklist parameter setting interface,and the data query interface.Explain the composition of the software program,including the calibration parameter setting program,data acquisition program,data processing program,and so on.Finally,the experimental data show that the calibration device of the gas volume correction instrument developed in this paper can meet the needs of market calibration.At the same time,the calibration device of the school has the characteristics of high reliability,high automation and high efficiency. |
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