Cooling Unit – How it Works Burner www.PropaneFridge.
Cooling Unit – How it Works Boiler A precise heat (electric heater element or gas flame) is applied to the boiler to begin operation. Heat is transferred from the outer shell of the boiler through the weak ammonia solution to the perk tube. (Most Zero product has a 110V capability - the Consul, Crystal Cold and the Frostek do not) The perk tube is provided with a rich ammonia solution (a high percentage of ammonia to water) from the absorber tank.
Evaporator Liquid ammonia enters the low temperature evaporator (refrigerator/freezer) and trickles down the pipe, wetting the walls. Hydrogen, supplied through the inner pipe of the evaporator, passes over the wet walls, causing the liquid ammonia to evaporate into the hydrogen atmosphere at an initial temperature of around -20º F. The evaporation of the ammonia extracts heat from the refrigerator/freezer.
The Fuse. The fuse on many cooling units and in this graphic is a steel tube, the end of which is filled with solder. The plug is hollow and filled with solder. In either case, the fuse is the weak link of the system. If pressure inside the cooling unit were to rise beyond a reasonable level for some reason, the fuse is designed to blow and release the pressure. This would make the cooling unit inoperable, but is necessary for safety.