How Ice Makers Work
History
In the past, ice was made by factories and delivered to homes. The process was expensive, and it was considered a luxury to have ice. Thanks to ice makers, today we can make ice at home, and restaurants can make large supplies of ice for their customers. Thaddeus Lowe invented the first commercially available ice maker. It was a Carbon Dioxide cooled ice machine, and was patented under British Patent No. 952. In 1866, his ice was first sold in Dallas, TX.
Components of an Ice Maker
A basic ice maker consists of the following components:
- Condenser
- Filter-Drier
- Evaporator
- Capillary Tube
- Ice Cube Molds (upside down)
- Accumulator with liquid refrigerant coil around it
- Motor Compressor
- Motor Controller with Power
- Water Supply and drain
- Water Sprayer Tube
- Electric Heating Unit
- Ice Cube Bin with full bin shut-off control
Differences in Design
At this point it would be important to note that not all ice machines are created equal, and the description give for the mechanisms and processes in this article are specific to a certain type of ice maker with a certain type of design. Different manufacturers have different processes and designs, however practically all modern ice machines have several similarities.
The Refrigerant Cycle
The process of making ice may seem rather complex to a novice. Liquid refrigerant is needed for the system to operate. The refrigerant flows from the condenser through a filter-drier. It then goes through a capillary tube into the evaporator, which surrounds the ice cube molds. The ice cube molds are upside down or vertical, so that when the ice is made it can fall via gravity into the ice cube bin.
In the evaporator, some of the refrigerant becomes a vapor, which enters an accumulator. The accumulator acts as a heat exchanger because it has a coil with liquid refrigerant around it. The vapor is pulled from the accumulator to the compressor. The vapor is then compressed and pushed into the condenser. This refrigerant cycle is repeated continuously until the machine has made enough ice to end the cycle.
The Ice Making Mechanism
Cold water travels from the water supply line to a water sprayer tube. It is then sprayed into the upside-down ice cube molds. The molds are at a low temperature because they are surrounded by the evaporator, as described above. When water touches the surface of the molds, it freezes. The ice builds up in the molds until ice cubes are formed. But, how do the ice cubes end up in the ice cube bin? Well, there is an electric heater that heats the ice cube molds just enough so that the cubes fall out. They fall down a chute and into the bin. At this point, the refrigeration cycle stops. It will start again to make new ice cubes, until the ice cube bin is full. When full, a metal lever at the top of the bin gets pushed up by the ice, and causes the process to stop.
References
- Thaddeus Lowe: http://www.thaddeuslowe.name/IIicemachinepatent.htm
- Althouse, Turnquist, and Bracciano. Modern Refrigeration and Air Conditioning, 18th ed. Tinley Park, IL: The Goodheart-Willcox Company, Inc., 2004.
This content was written by Valerie Johnson and is copyrighted 2012.
E-mail: JHC@cooljohnson.com