Apart from orifice and turbine meters, the bellows-type meter is the most popular type of device used to measure the volume of gas flowing through it in situations where a provider needs to bill an individual receiver for the gas they use. The device was patented in 1815 by Samuel Clegg of Great Britain, who worked in the gas production industry. Gas meters were initially used mainly in industrial facilities that needed gas for production purposes and came to be used in households as different types of domestic gas appliances became widespread. Its name comes from the bellows found inside it. The bellows have a known capacity and as they fill with gas, they allow the amount taken from the network to be measured. The movement of the bellows is transmitted to a counter mechanism (or one with a gauge, as is the case here) through a servomechanism, thereby allowing gas consumption to be measured. The bellows gas meter presented here was produced by the German Kromschröder AG company which was established in Osnabrück in1865 as a joint stock company. The company specialised in the production of gas meters and a wide range of farming equipment under the Kromag brand. The company established branches in several cities, including Wrocław, where the device shown here was manufactured. The company is still in operation today. This item worked in Wschowa in Lublin province, as evidenced by the plaque installed by the local gas provider.
Interesting fact: for bellows gas meters made in Germany, the maximum throughput was often expressed as the number of flames. In the case of this particular device, the rating of “20 flames” is equivalent to a throughput of 3 m3/h.

References:
K. Dreyer, Kromschröder, “Geschichte der Landtechnik” blog,
http://www.landtechnik-historisch.de/historische-landmaschinen/kromschroeder-ag/ (Accessed: 9.05.2021).
Gazomierze w sieci virtual exhibition, Wirtualne Muzeum Gazownictwa, https://wmgaz.pl/wirtualne-wystawy/gazomierze-w-sieci (Accessed: 9.05.2021).