Development Of A Temperature Adaptability Test Rig For Diaphragm Gas Meter

Diaphragm gas meter is one of the main measuring instruments widely used in urban household coal gas,natural gas,liquefied petroleum gas(LPG)and so on.At present,the diaphragm gas meter is calibrated at room temperature,however,in practical application,it is affected by the geographical position and the temperature change of the four seasons,the actual working temperature of the diaphragm gas meter is different from the room temperature.According to the requirement of new diaphragm gas meter evaluation outline,this subject used the existing equipment of Tianjin metrological supervision and Inspection Institute to study,design and build the temperature adaptability test rig and meet the requirements of national standard.According to the new diaphragm gas meter evaluation outline,this article is based on an existing bell prover gas flow standard device of Tianjin metrological supervision and Inspection Institute to study the temperature adaptability test rig and has achieved the following works:(1)Structure design of the rig.This rig mainly includes the bell prover gas flow standard device,gas drying device,constant temperature system,gas heat exchange system,calibration system and gas pipeline.(2)Uncertainty analysis of the rig.The uncertainty components including: the bell prover gas flow standard device,heat exchange,integrated temperature transmitter,pressure transmitter and air humidity.(3)The design of control system.The control system includes hardware equipment selection,to realize data acquisition and signal output by PLC as lower machine and using the SCADA software as the host computer to monitor the process of testing and data processing.The diaphragm gas meter temperature adaptability test rig developed in this thesis has achieved the following technical specification: The expanded uncertainty of the rig as a whole is 0.28%(k=2),meeting the requirements of diaphragm gas meter G1.6 ~ G40 temperature adaptability test,the deviation of the test medium temperature of gas meter installation location and the constant temperature box is less than ± 0.1 ?.