several fatal accidents were registered. They were caused by the refrigerators leaking methyl chloride. In the quest of replacing dangerous refrigerants – especially methyl chloride – collaborative research ensued in American corporations. The result of this research was the discovery of Freon. In 1930, General Motors and DuPont formed Kinetic Chemicals to produce Freon, which would later become the standard for almost all consumer and industrial refrigerators. The original "Freon" produced at this time was chlorofluorocarbon, a moderately toxic gas causing ozone depletion. Principle of ice making All refrigeration equipment is made of four key components; the evaporator, the condenser, the compressor and the throttle valve. Ice machines all work the same way. The function of the compressor is to compress low-pressure refrigerant vapour to high-pressure vapour, and deliver it to the condenser. Here, the high-pressure vapour is condensed into high-pressure liquid, and drained out through the throttle valve to become low-pressure liquid. At this point, the liquid is conducted to the evaporator, where heat exchanging occurs, and ice is created. This is one complete refrigeration cycle. Consumer icemakers Freezer icemakers Automatic icemakers for the home were first offered by the Servel company around 1953. They are usually found inside the freezer compartment of a refrigerator. They produce crescent-shaped ice cubes from a metal mold. An electromechanical or electronic timer first opens a solenoid valve for a few seconds, allowing the mold to fill with water from the domestic cold water supply. The timer then closes the valve and lets the ice freeze for about 30 minutes. Then, the timer turns on a low-power electric heating element inside the mold for several seconds, to melt the ice cubes slightly so they will not stick to the mold. Finally, the timer runs a rotating arm that scoops the ice cubes out of the mold and into a bin, and the cycle repeats. If the bin fills with ice, the ice pushes up a wire arm, which shuts off the icemaker until the ice level in the bin goes down again. The user can also lift up the wire arm at any time to stop the production of ice. Later automatic icemakers in Samsung refrigerators use a flexible plastic mold. When the ice cubes are frozen, which is sensed by a Thermistor, the timer causes a motor to invert the mold and twist it so that the cubes detach and fall into