Thermoplastic Encased Immersion Heater
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
This article discloses a thermoplastic sheathed immersion heater for use in a corrosive chemical bath. The heater is encased by a sheath whose diameter at the operating temperature of the heater has a zero clearance. Temperature control is affected by a dual-control scheme which utilizes both temperature sensors imbedded in the heaters and external temperature sensors. If the sheath is too tight at temperatures below the operating temperature, then failure can result as the temperature increases and the yield strength of the sheath material falls, until the residual tensile stress in the sheath equals its yield strength.