钢卷尺弹性变量对检定立式金属罐误差分析

An Error Analysis on the Elastic Variable of Steel Tape in Calibrating Vertical Metallic Tanks

在立式金属罐计量检定中,测量圆周长时,如达不到围尺法(外测)检定条件,只能采用内铺尺法,测量完成后需根据刚卷尺的有效检定证书对测量结果进行修正。但是检定证书上的修正值是在刚卷尺受力的情况下给出的(刚卷尺具有弹性,施加49N拉力时在弹性刚度范围内刻度),而内铺尺法是无法对刚卷尺施加外力的。所以,刚卷尺在检定时的状态与用于测量时的状态不一致,直接用检定证书上的修证值进行修正时,会产生修正误差。通过对刚卷尺的弹性变量研究,提出了修正方法。

In the measuring calibration of vertical metallic tanks,if the calibrating condition for the external encircling approach of steel tape can not be satisfied,the internal laying approach of steel tape has to be used while measuring the length of circumference.Therefore,it is necessary to modify the measuring result according to the effective verification certificate of steel tape after the measurement.But the modifying value in the verification certificate is given under the condition of steel tape with pressure,because the steel tape has its elastic property,which is in the elastic range of steel when 49N pulling force is imposed.However,the internal laying approach of steel tape can not place any outside force on the tape.Therefore,the state of steel tape in the calibration is not consistent with the state in the measurement,which results in the modifying errors while the modifying value in verification certificate is used directly.The paper studies the elastic variables of steel tape and then puts forward the modifying methods.