The ammonia gas is taken from the refrigerating section and compressed by a pump. The ammonia starts from the compressor under a high pressure and temperature and passes to a cooling coil, which is the condenser. Here, by means of a cold water sprinkler, the gas is cooled to 45° or 50° F. and is condensed under high pressure to a liquid state. It then passes to the storage tank.
When ammonia is received ready for use, it is in a liquid state and enclosed in steel drums, which are only partly filled, leaving space enough for expansion so as to prevent an explosion. Ammonia drums have exploded, but always under conditions of overheating, for in general, with proper care, there is no danger.