70t级铁路罐车容积的几何测量法研究

Study on the Geometric Measurement Methods for the Volume of 70 t-Grade Railway Tank Cars

根据70t级铁路罐车的锥形罐体结构及其特征参数,建立罐体容积的计算模型。参照圆柱体铁路罐车容积的测量方式,并结合锥体铁路罐车自身的结构特点,确定其需要测量的罐体特征参数。采用罐内几何测量法时,测量的罐体特征参数包括内横直径、内竖直径和内总长;采用罐外几何测量法时,测量的罐体特征参数包括外横直径(和(或)加温套外廓宽和(或)导流板外廓宽)、外周长、外总长、上板厚、封头壁厚、加温套厚。以GQ70型铁路罐车为例进行的罐体容积几何测量试验和计算分析表明:采用两两对称的4个测量截面测量罐体特征参数足以满足测量的需要,所得到的测量结果不确定度为4×10-3(k=2),符合铁路罐车容积检定规程的要求,可以用于70t级铁路罐车容积的实际测量。

According to the conical tank structure and characteristic parameters of the 70 t-grade railway tank cars, the computational model for the volume of the tank is established. Referring to the measuring methods of the railway tank cars with cylindrical tanks and combining them with the structural characteristics of the conical tank cars, the tank characteristic parameters required are determined. When the tank-internal measurement method is adopted, the measured characteristic parameters of tank body include the in- side cross diameter, the inside vertical diameter and the inside total length. When the tank-external geometric measurement method is adopted, the measured characteristic parameters of tank body include the outside cross diameter and/or the outer distance of the two edges of the steam jacket and/or the outer distance of the two liquid guiding plates, the outside perimeter, the outside total length, the thickness of the upper tank shell, the thickness of the tank head shell and the thickness of the steam jacket. Taking GQ70 railway tank car for example, the geometric measurement tests and calculation analyses of tank volume show that： to adopt four measuring cross sections, which are two-symmetry separately, to measure the tank characteristic parameters can meet the requirement of the measurement. The obtained measurement uncertainty is 4 × 10^-3 （k=2）, which has satisfied the national verification regulation of the volume of the railway tank car. The methods can be used in the actual volume measurement for 70 t-grade railway tank cars.