Device name：Upgraded Horizontal Shrinkage Expansion Instrument
Model：YC-HSP540D
Origin：Beijing
Purpose：A special instrument for measuring the change of length (volume) of concrete specimens during hardening under certain environmental conditions.
型号：YC-HSP540D
用途：用于测量混凝土试件在一定环境条件下，硬化过程中长度（体积）发生变化的专用仪器，可为建筑科学研究院所、门、设计和施工单位对砊的特性进行研究、教育、质量控制和检测提供可靠依据。
执行标准：
GB/T50082-2009《普通混凝土长期性能和耐久性能试验方法标准》
现有卧式混凝土收缩膨胀仪存在如下不足：
（1）标准中校准杆材质建议选择硬钢或石英玻璃材质制作，但目前市场上的校准杆基本上都为不锈钢材质，不锈钢校准杆的线膨胀系数很大，易因温度波动影响造成误差。
（2）千分表精度差，即使选用业内较好的电子千分表也有±3um的测量误差，一般的千分表误差在±5um以上，这对于混凝土试件后期收缩量本来就很小而言，会造成很大的误差。
（3）试验过程人工读数记录，易因人为笔误或在数据抄写过程中失误造成错误。 
并且，由于在整个试验周期中，同一个试件要测量十几次，上述3种误差因素会被不断放大，很有可能出现前后试验结果相互矛盾的现象，且无法找到问题根源。 
The shortcomings of available horizontal concrete shrinkage expansion meter:
(1) Hard steel or quartz glass is recommended for the calibration rod material in the standard, but the available calibration rod in the market is mostly made of stainless steel. Its linear expansion coefficient is too high, which is easy to cause errors due to the influence of temperature fluctuation.
(2) The accuracy of the micrometer is poor, even if the best electronic micrometer is used, because its measurement error is more than 3um. Generally, the error of the micrometer is more than 5um, which will cause a great error for the shrinkage of concrete specimens in the later period.
(3) Manual reading records during the test process are prone to errors, which is caused by human errors or errors in data transcription.
Moreover, the same specimen needs to be measured more than a dozen times in the whole test cycle. The above error factors will be enlarged continuously, and it is likely that there will be conflicting phenomena between early and later results. We can’t find the root cause of the problem.