Bi- Metal Temperature Switch For Cold Weather Refrigerator

Rather than multitude of lines I will try picture the idea. You live in climate where it gets cold and stays cold, below 36°F, for long period of time. Top two lines are thin strip of brass and thin strip of iron sweat soldered together. I found little information on sweat soldering and a rivet near each end does the same job where unequal expansion of metal causes bending of strips. They could be round disks with edges welded and bowing in and out with temperature changes. Mounted metal strip bend and close contacts to fan circuit as temperature changes. Circuit at bottom, left 49 ohm resistor is hair dryer with heating element out. An air filter over intake of fan filters and restricts free flow of cold air. SPST switch is a covered bi-metal switch inside cooler box to turn on hair dryer mounted outdoors to blow cold air through pipe into cooler box and second pipe exhausts warmer air under floor. When adjusted well, it should regulate temperature within 4 degrees. If using tilt switches or mercury switches make sure of safety ratings for line voltages.

published 8 years ago