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US 4,072,847 AGranted
Electrical heater for heating liquid
AssigneeLiquifry Company Limited
InventorJohn L. Craven
Life of this patent
Estimating the term…
Abstract
An electrical heater comprises a sealed glass tube containing a sealed tubular structure formed by, (a) a metal tube containing an electrical heating element insulated from the metal tube, and (b) a plastics tube sealed to one end of the metal tube and containing a thermostat for the heating element.
Claims7
An electrical heater for heating a liquid, the heater comprising:
- a pair of conductors for applying electrical energy to the heater;
- an electrical heating element coupled across said conductors;
- a temperature-sensitive device coupled between said heating element and one of said conductors for feeding of current to said heating element to control the operating temperature of said element as a function of ambient temperature;
- a tubular enclosure sealed against ingress of water and formed by a metal tube closed against ingress of water at one end, an electrically insulative plastics tube joined at one of its ends in water-tight manner to the other end of said metal tube, and a sealing plug through which said conductors extend and which seals the other of the ends of said plastics tube, said heating element being within said metal tube and said temperature-sensitive device being within said plastics tube;
- electrical insulating means electrically insulating said heating element from said metal tube;
- and a glass tube containing said tubular enclosure and which is closed against ingress of moisture at one end and is sealed against ingress of water at its other end by sealing means through which said conductors pass.
3 more elements
Dependencies are inferred from the claim text.