低温计量不再难——利用高准流量计进行低温计量

无可动部件和无接液动态组件的高准流量计非常适合应用于低温作业领域．这使生产气体在低温液体状态下的输送或贮存更为便利。

Bubble counter based on photoelectric technique for leakage detection of cryogenic valves

In order to overcome the inconvenience of manual bubble counting, a bubble counter based on photoelectric technique aiming for automatically detecting and measuring minute gas leakage of cryogenic valves is proposed. Experiments have been conducted on a self-built apparatus, testing the performance with different gas inlet strategies (bottom gas-inlet strategy and side gas-inlet strategy) and the influence of gas pipe length (0, 1, 2, 4, 6, 8, 10 m) and leakage rate (around 10, 20, 30, 40 bubbles/min) on first bubble time and bubble rate. A buffer of 110 cm3 is inserted between leakage source and gas pipe to simulate the down- stream cavum adjacent to the valve clack. Based on analyzing the experimental data, experiential parameters have also been summarized to guide leakage detection and measurement for engineering applications. A practical system has already been suc- cessfully applied in a cryogenic testing apparatus for cryogenic valves.

张家港市计量所在全省率先开展液化天然气(LNG)加气机校准工作

液化天然气(liquefied natural gas,LNG)是将气田开采出来的天然气压缩、膨胀、液化冷却至-162℃后形成的低温液体,液化后其体积为气态天然气的1/625,体积能量密度约为汽油的72%。LNG是目前全球增长最快的一次能源,与传统的石油类燃料及CNG(压缩天然气)相比,LNG具有便于运输、储存能量大、运行压力低、更清洁环保等优点。LNG加气机是将LNG加气站输送的LNG加注到LNG汽车的一种超低温计量设备。

JJG1114-2015《液化天然气加气机检定规程》解读

一、引言 液化天然气（LNG）加气机为近年来新出现的超低温计量器具,其产品涉及低温设备的安全检测和贸易结算的公平性,只有强制达到通用技术、计量性能等要求,才有可能满足安全防护、贸易结算等方面的使用要求。目前,全国已有上百家LNG加气机生产企业,已有近3千座LNG加气站投入使用,有约20万辆LNG汽车投入运营。