A gasometer is an object which safely holds a type of gas at a steady temperature and a controlled pressure. Generally, they are part of a larger piping operation, used primarily to help maintain proper pressure within the system. However, gasometers can also simply be used to store the gas for later use.
The idea of the container has been used since at least the early 1800s. At the time, William Murdoch developed lighting systems using gas as a power source. In order to store the necessary gas, he developed a container that would maintain the safe pressure system and could keep track of the usage by reading a meter.
Basic gasometers use a large container filled with gas and water. The gas seeps to the top of the container and the water acts as a buffer at the bottom to maintain the pressure. Two pipes are placed inside the facility, one designed to push gas in and another to push the gas out. By adjusting the amount of water within the container, gas is pushed out into the piping system. Gas can then be refilled into the container, which again moves to the top.
The waterless gas holder was developed during the 20th century. This version utilizes a sealed system that holds the gas using the strength of the container's construction. The major benefit of this system is that the pressure is maintained at a level that allows the gas to flow at very fast speeds. Basically, as soon as the gas is turned on within the system, it will flow from the container to the necessary location nearly immediately.
The gasometer design is more frequently seen in Europe rather than the United States. During the Victorian era, specifically, gas holders were the most common way of providing power to communities. Since the U.S. took longer to develop into an urban society, the design was not implemented to the same level.
Many gasometers use natural formations to aid in the storage ability of the container. One of the best features are salt formations. Salt caverns offer a natural durability that helps store gas. A gasometer built atop a salt cavern features water pumped into the cavern, creating saline, further helping keep the pressure and temperature intact. The likelihood of the gas escaping is highly unlikely and essentially creates a natural gasometer that can last seemingly forever.