Chongqing F2 grade 1-ton stainless steel weight with calibration certificate from the metrology institute

Chongqing F2 grade 1-ton stainless steel weight with calibration certificate from the metrology institute

500kg and 1000kg are the two most commonly used large weight specifications in our daily calibration. This article focuses on the use and traceability of laboratory large weights, and explores a 1000kg F2 grade (combination) weight that can achieve loading and unloading of 500kg and 1000kg in two ranges, which is convenient for traceability and can be applied to the detection of small electronic hanging scales and low-level weights, avoiding the back and forth switching of different weights, improving detection efficiency and saving laboratory space.

With the development of the economy and the popularization of large-scale weighing applications, the application of standard large weights in electronic hanging scale detection, electronic platform scale detection, and weight value transmission is becoming increasingly widespread. Among them, 500kg and 1000kg are the two most commonly used specifications. For standard large weights, the higher the grade and the greater the quality, the more difficult it is to trace. Currently, many municipal metrology institutes do not have the measurement ability of 1000kg F2 grade weights, which causes inconvenience to the traceability of weight values. This article focuses on the application of two types of large standard weights, 500kg and 1000kg, in the traceability and transmission of measurement values. It is conducted by a metrology institute and a weight manufacturing enterprise Explore and develop a combined standard large weight, which not only facilitates traceability but also saves laboratory space, testing, and transportation time.

Analysis of the Current Status of Two Weights: Currently, the shapes of 500kg and 1000kg large weights on the market are mainly pillow shaped, lock shaped, and cylindrical. Compared to pillow type weights and lock type weights, cylindrical weights have higher loading accuracy, although transportation is not convenient. Considering that our designed set of large weights is mainly for laboratory use, cylindrical weights are chosen for design.

3 1000kg (combination) weight design

Based on the actual usage needs of our unit, in collaboration with Changzhou Fuyue Ju

Code Co., Ltd. jointly designed and manufactured a set of 1000kg F2 grade

(Combination) weights. Changzhou Fuyue Weights Co., Ltd., as a leading manufacturer of weights in China, holds a prominent position in terms of weight structure design and manufacturing processes. The weight group designed in this project consists of two 500kg F2 weights, mainly used for transmitting the measurement values of small electronic hanging scales and standard large weights of M1 level and below of 500kg and 1000kg in the laboratory.

3.1 Shape selection of weights

Taking into account the actual use of large weights in the laboratory and the advantages and disadvantages of different weight shapes currently available on the market, this set of 1000kg (combination) weights has been decided to adopt a cylindrical weight structure, as shown in Figure 1.

The cross-sectional view of the weight is shown in Figure 2. The entire (combination) weight consists of one M48 lifting bolt, two cylindrical weights, and one connecting rod. The lifting bolt, connecting rod, and upper weight together form a 500kg weight, while the lower weight is an independent 500kg weight, with an accuracy level of F2. This forms a (combination) weight that can load both 500kg and 1000kg.

3.3 Material selection of weights

Due to the fact that the weights are mainly used in laboratories and have a grade of F2, and according to the weight regulations, the weights should be made of corrosion-resistant metals or alloys, we ultimately chose stainless steel with a density of 7.92g/cm3 and a magnetic susceptibility of 0.2 as the material for our weight production.

3.4 Distribution of adjustment chambers for weights

According to our usage requirements, the lifting ring, connecting rod, and upper weight together form a 500kg weight, while the lower weight is an independent 500kg weight with an accuracy level of F2. Therefore, adjustment chambers are equipped around and at the top of the cylindrical weight to adjust the weight and center of gravity balance of the weight.

Other designs for 3.5 weights

Actual application effect of 4 weights

During the production of weights, the upper weight has a traditional F2 lock type large weight and a 1000kg (combination) protruding part at the center of the lower end, while the lower weight has a partial groove at the center of the upper end. The weight can serve as a limit rail when loaded or unloaded on the same CCT2000K mass comparator. Two measurement points, 500kg and 1000kg, were measured 10 times each, and the measurement data is shown in Table 2. The measurement repeatability of the two points of 500kg and 1000kg of the weight is

According to the formula for evaluating measurement repeatability:

1.0g and 1.4g, the measurement repeatability of traditional weights at these two points is S y)='2=(yiY) 1.2g and 1.6g. It can be seen that compared to traditional lock type large weights, the (combination) n-1 weight has multiple measurement results due to factors such as material and shape, as shown in Table 2, on the same comparator The consistency of the combination is higher.

Chongqing F2 grade 1-ton stainless steel weight with calibration certificate from the metrology institute