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US 4,640,226 AGranted
Bird watering apparatus
OwnerWalter H. Liffinventor
Life of this patent
Estimating the term…
Abstract
A watering container for birds having spaced inner and outer walls integrally molded from plastic with electrical heating elements contacting the inner wall controlled so that energy is provided to the heating elements is progressively increased with the fall of ambient temperature below freezing.
Claims6
A temperature controlled birdbath device comprising:
- (a) a molded plastic container having:
- (1) an inner wall defining a closed bottom, sidewalls and an open top;
- (2) an outer wall integrally joined to said inner wall at said top and extending below said closed bottom spaced outward of said inner wall to define an open bottom below said closed bottom;
- (b) an electrical resistance heating element wound in contact with the bottom surface said inner wall consisting of negative temperature coefficient of conductivity heating cable;
- and,
- (c) means to connect said heating element to a source of electrical energy, said heating element providing increasing electrical energy as the ambient temperature falls below the freezing temperature of water.
3 more elements
Dependencies are inferred from the claim text.