It is generally known that the evaporation temperature of a liquid decreases as the pressure of the surrounding air decreases
. Thus, water can be drawn from a material at lower temperatures in a near vacuum dryer environment thereby expending less energy if a lower temperature can be utilized. As a result, a number of prior art devices are directed to the modification of clothes dryers which have been developed to incorporate a vacuum dryer or vacuum dryer like chamber. However, these devices lose efficiency in that they constantly pump air into a chamber for purposes of discharging a volume of air and water vapor out of the device by use of a vacuum dryer pump. Such devices require additional power as the incoming air must be circulated and in most cases heated.
The interior of the chamber is fluidly coupled to a vacuum dryer pump 18 capable of a drawdown vacuum dryer of approximately 28 inches Hg. The vacuum dryer pump is water sealed with a water inlet 80 drawn through strainer 82 and controlled by inlet solenoid 84 . The vacuum dryer pump 18 operates initially to withdraw air from the chamber through exhaust check valve 19 and associated piping 86 for maintaining a low pressure environment during the drying cycle. The vacuum dryer pump exhausts air through the air silencer 87 out of outlet 93 . The pump includes a trap 89 to further seal as well as prevent back flow of water discharged to the drain 91 .
The chamber may be heated by an electric coil, utilize hot water preheater lines or the hot fluid line 24 as provided by a compressor system. The pressurized fluid is directed through an expansion valve before being directed through a condensate coil 28 . The condensate coil 28 condenses moisture from clothing placed within the chamber with the condensed moisture collected in an internal collection tank 31 . The condensate is held until the drying cycle is complete, or if full during the cycle, purged by vacuum dryer pump 18 through check valve 19 to collection tank 30 . A set of cooling coils 36 may be routed from the condenser 28 and through the collection tank so as to provide cooling action for the vacuum dryer pump 18 without the system consuming more energy. The condensate in the collection tank is relatively cool due to its inner action with the cold condenser coil 28 and will also provide cooling action. The cooling action extends the life of the vacuum dryer pump and increases the overall efficiency of the system.