TUBE ELECTRIC HEATER WITH THERMAL CIRCUIT BREAKER AND METHOD FOR ITS MANUFACTURING Russian patent published in 1999 - IPC

FIELD: electrical engineering. SUBSTANCE: thermal circuit breaker is located in jacket of electric heater with optimal dependence of sizes of gas-permeability volumes shaped by ends of temperature-sensitive member, inner surfaces of tubes which are designed as parts of electrodes and ends of rods which are tightly inserted into said tubes, on volume of alloy of temperature-sensitive element which is located in space between tubes. Novel features of method for manufacturing of tube electric heater involve reduction of housing of tube heater under condition of keeping gas-permeability volumes V1 and V2 shaped by ends of temperature-sensitive member of circuit breaker, inner surfaces of tubes which are designed as parts of its electrodes and ends of rods which are tightly inserted into said tubes. These values conform to condition 0,8V₃≤V₁+V₂≤2,5V₃,, where V3 is volume of alloy of temperature-sensitive member which is located in space between tubes. Thermal processing involves protection of part of metal jacket, in which circuit breaker is located, against heating on at least 20 mm to keep its temperature by at least 20 C below than triggering temperature of circuit breaker. EFFECT: increased safety, quality and reliability of operations. 3 cl, 3 dwg