Frost protection system for automatic carwash - provides air flow to remove water from channels if temp. falls below freezing point

摘要

If the water remaining in an automatic car-washing machine or vehicle steam-cleaning machine freezes, damage to the pumps etc. may occur. If the thermostat in the present circuit detects a temp. below freezing point at any time that the machine is not in use, a stream of warm air is blown through the channels of the machine supplied by the high pressure water pump, to remove any accumulation of water and to raise the temp. of those channels above freezing point. The air-flow continues for a number of seconds determined by a capacitor in a timing circuit, or until a signal is received indicating that another vehicle is in place for washing or cleaning. If a temp. below freezing is detected during a washing or cleaning operation, the warm air 'purging' starts after the operation is complete.