Gas meter - gas meter (English spelling)

A meter that measures the volume of gas that passes through a pipe by accumulating it. It is widely used for measuring the volume of gas when trading city gas and liquefied petroleum gas (LPG). There are various types, such as membrane type, wet type, and rotor type. All of them use a measurement method called actual measurement, which has a measuring chamber of a fixed volume separated by a movable wall, and measures the volume by filling this part with gas and counting the number of times it is pumped out in sequence. Membrane gas meters are used for home use, and have two measuring chambers separated by a flexible membrane, and the movement of the membrane operates a valve to alternate the gas flow path. They are highly durable and can be used for about 10 years without maintenance. Wet gas meters use the free liquid surface of water or oil as a partition, and multiple measuring chambers attached to a rotating shaft measure gas in sequence as they rotate. Although they are inconvenient to use, they are used as reference meters due to their high accuracy. Rotor gas meters are designed to form measuring chambers that move in sequence as they rotate between a rotor and the surrounding walls. Although some leakage is unavoidable due to a small gap between the rotor and the wall, this is a small-sized meter that can measure large volumes. In addition to the above-mentioned actual measurement type, since around 1980, devices that combine various flow meters and flow velocity meters (throttle flow meters, Coriolis flow meters, impeller flow meters, etc.) with electronic integrating mechanisms have also been used as gas meters for commercial gas transactions.

[Mitsui Kiyoto]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

管中を通過したガスの体積を積算して計量する計器。都市ガスや液化石油ガス（LPG）を取引する際の計量などに広く用いられている。膜式、湿式、回転子型などの種類がある。これらはいずれも実測式とよばれる測定方法によっており、可動壁で仕切られた一定体積の計量室をもち、この部分にガスを満たして順次送り出す回数を数えて計量を行う。膜式ガスメーターは家庭用として使われているもので、柔軟な膜を隔壁とする2個の計量室をもち、膜の動きによって弁を作動させてガスの流路を交互に切り換える。耐久性に優れ、手入れなしで10年程度使用できる。湿式ガスメーターは水または油の自由液面を隔壁とし、回転軸に取り付けた複数個の計量室が回転しながら順次ガスを量り取る。取り扱いは不便だが、精度が高いため基準メーターとして用いられる。回転子型ガスメーターは、回転子と周囲の壁との間に回転によって順次移動する計量室を構成するようにつくられている。回転子と壁との間にわずかなすきまがあるため多少の漏れは避けられないが、小形で大容量の計量を行うことができる。前記の実測式のほか、1980年ごろから各種の流量計・流速計（絞り流量計、コリオリ流量計、羽根車など）と電子式積算機構を組み合わせた装置が取引用ガスメーターとしても利用されている。

［三井清人］

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