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液体活塞式压力计量值修正模型研究

Research on the Measurement Value Correction Model of Liquid-Medium Piston Gauges

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由于液体活塞式压力计专用小砝码的质量在计算时参考了零压活塞有效面积,大砝码的质量在计算时仅考虑加载大砝码导致的活塞系统形变,因此加载标称压力砝码的活塞式压力计计量的实际压力小于标称压力.基于活塞式压力计的基本原理,推导了测量上限为25 MPa及以上的液体活塞式压力计量值修正模型;测量上限60 MPa和250 MPa的活塞式压力计相对压力修正值变化结果表明:相对压力修正值的绝对值随着加载小砝码的数量近线性递增,但随加载的大砝码的数量呈现趋势逐渐减弱的非线性递增;相对压力修正值的极限值与活塞压力形变系数和测量上限成正比;整体上小砝码对相对压力修正值影响权重大于大砝码,活塞测量上限附近小砝码加载数量最多的压力测量点的相对压力修正值取得极限值;250 MPa活塞的相对压力修正值极限值为-5.17×10-5,超过0.005级活塞式压力计的最大允许误差;基于专用砝码质量最大允差的限制,0.01级及以上25 MPa和0.02级及以上250 MPa的活塞式压力计输出量值必须进行修正才能保证其压力量值传递的准确性.
The mass of the special small weights used in liquid-medium piston gauges is calculated with reference to the effective area of the zero-pressure piston,while the mass of the large weights only considers the deformation of the piston system caused by loading the large weights.As a result,the actual pressure measured by the piston gauge loaded with nominal pressure weights is less than the nominal pressure.Based on the basic principles of piston pressure gauges,a measurement value correction model for liquid-medium piston gauges with a measurement upper limit of 25 MPa and above is derived.The results of the relative pressure correction values for piston gauges with upper measurement limits of 60 MPa and 250 MPa show that the absolute value of the relative pressure correction value increases nearly linearly with the number of small weights loaded but exhibits a nonlinear increase with a gradually weakening trend as the number of large weights loaded increases.The limit value of the relative pressure correction value is proportional to the pressure deformation coefficient and the upper measurement limit of the piston gauge.Overall,the influence of small weights on the relative pressure correction value is greater than that of large weights,and the relative pressure correction value reaches an extreme value at the pressure measurement point with the largest number of small weights loaded near the upper limit of the piston measurement.The relative pressure correction limit of the 250 MPa piston is -5.17×10-5,exceeding the maximum allowable error of the 0.005-level piston gauge.Based on the limitation of the maximum tolerance of the special weight mass,the output measurement values of 25 MPa piston gauges of grade 0.01 and above and 250 MPa piston gauges of grade 0.02 and above must be corrected to ensure the accuracy of their pressure value transmission.

metrologypressure measurementliquid-medium piston gaugesnominal pressure weightseffective area of pistonrelative pressure correction valuepressure deformation coefficient

曾麟、周四清、陈岳飞

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湖南省计量检测研究院,长沙 410014

计量学 压力计量 液体活塞式压力计 标称压力砝码 活塞有效面积 相对压力修正值 压力形变系数

湖南省自然科学基金

2023JJ60535

2024

10.12338/j.issn.2096-9015.2024.0024

计量科学与技术
中国计量科学研究院

计量科学与技术

影响因子：0.187
ISSN：2096-9015
年,卷(期)：2024.68(4)
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