Apparatus for defrosting evaporator of a refrigeration unit

Claim 1

In a refrigeration unit comprising a compressor, condenser, expansion valve and evaporator coil, each of which is operably connected in the named conventional order by conduit means for flowing a refrigerant therethrough in a conventional path, the improvement comprising: 1. conduit means connecting the discharge side of the compressor with the evaporator coil for passing compRessed and heated refrigerant gas through the evaporator coil, whereby the refrigerant gas is cooled and at least partially condensed and frost on the evaporator coil is melted; 2. conduit means connecting the evaporator coil with a second expansion valve for transporting the cooled and at least partially condensed refrigerant to the second expansion valve; 3. heat exchanger means, connected by a conduit to said expansion valve, for evaporating the expanded, cooled and partially condensed refrigerant, whereby the refrigerant becomes substantially completely gaseous; 4. conduit means connecting the heat exchanger means with the compressor for returning the gaseous refrigerant to the intake side of the compressor; 5. valve means for disrupting the said conventional path of refrigerant and providing the path of refrigerant defined by elements (1) through (4); 6. means for circulating water about the condenser; 7. conduit means connecting the condenser and heat exchanger means for passing the water from the condenser to the heat exchanger; and means for circulating the water about the heat exchanger means.