They're called ice machines or ice makers and they haven't really been around all that long. In fact, it was only a 100 years ago that ice was simply hard to come in most parts of the world. In the hotter areas of the world you would have had to buy the ice from some sort of delivery service. This service would import large blocks from a colder climate or from an industrial refrigeration plant. Because of this, buying ice cost quite a bit back then. However, if they wanted to keep their food fresh and cold they didn't have much choice. In the hottest parts of the world it was common to never see ice in your entire life.
All of this changed in the early part of the 20th century. This is when refrigerators became compact and more affordable and the production of ice was brought into the store on the corner and into the home. In the 1960s life became even easier when the automatic ice maker was introduced. What a thrill for everyone. Today, we take ice for granted.
If you are wonder how an ice maker, in a refrigerator works, first off they all use an electric motor that has an electrically operated water valve as well as an electrical heating unit. So, for the unit to have power to all of the elements, you need to hook the ice maker up to an electric circuit that powers a refrigerator. A water line has to be hooked up from the home to the refrigerator in order to have water to turn into ice. Both the water intake tube and the power line run through the back of the freezer.
After everything is hooked up, this is when the ice maker will start its cycle. This is usually controlled by a very simple electric circuit and then a series of switches. When the cycle begins, there is a timed switch in the circuit that will briefly send a current to a solenoid water valve. Most of the designs the valve will be placed behind the refrigerator and is connected to the central circuit through electrical wires. When the current goes down the wires, this charge will move the solenoid and open the valve.
The valve will only stay open for about seven seconds and this is when it lets the water in to fill up the ice mold. The mold is plastic and has connected cavities. These are usually curved and in a half circle shape. Each cavity wall has a small notch so each cube of ice will be attached to the cube right next to it.
After the mold is filled with water, the machine will wait for the water to freeze. It's the cooling unit in the refrigerator that does the work of freezing the water and not the ice maker. The ice maker has its own built in thermostat and will monitor the temperature level of the water when it's in the molds. When it gets down to a certain temperature, like 9 degrees F, the thermostat will close a switch in the electrical circuit.
When the switch is closed, it will let the current flow through the heating coil under the ice maker. When the coil heats up, it will warm the bottom of the mold and the ice cubes will loosen from the mold. The circuit will activate the ice maker's motor next. The motor will spin a gear and it will rotate another gear that is attached to a plastic shaft. This has ejector blades that stick out from it. When the blades revolve they will scoop the ice up and out of the mold and then push them out the front of the ice maker.
There are some plastic notches in the front of the machine in the housing that will match up with the blades. The blades will go through the notches and the ice cubes then will be pushed out to the collection bin under the ice maker itself. After the cubes drop into the bin, the arm will fall down again. Once the arm reaches the lowest resting point it will throw the switch in the circuit and this will start the water valve again to start another cycle of producing ice.