Tank defroster for beverage dispensing machine

Claim 1

Apparatus for dispensing soft drinks in slush-ice form while maintaining the proper consistency of the slush-ice, comprising a tank for holding a soft drink, a tubular cooling coil wound helically around the outside of said tank, and connected to a refrigeration unit, an electric heater coil wound helically around the outside of said tank with its convolutions alternating with those of said cooling coil, a layer of mastic around the outside of said tank and in which said coils are embedded to secure said coils to said tank, and to maintain the convolutions of the two coils spaced from one another, a housing surrounding said tank in spaced relation to said tank and the layer of mastic, a layer of thermal insulation disposed in the space between said tank and said housing and encapsulating said tank and said layer of mastic, a spigot connected at one end to the bottom of said tank, and projecting at its opposite end through said insulation and said housing to the exterior of the housing, and operable for controlling the flow of drink from the tank, and means for actuating said refrigeration unit and said heater coil, and movable control means for said actuating means operative when said refrigeration unit is actuated to render said heater coil inoperative, and vice versa, thereby to control the size of the ice crystals formed in said tank, said layer of mastic being flexible, to permit expansion and contraction of said coils in response to temperature changes produced therein.