Abstract: A PTC heater for securely positioning resistors is disclosed. The PTC heater has two insulating plates having a plurality of square or rectangular through holes, a conductive position plate having a plurality of square or rectangular through holes facing toward those in the insulating plates and a resistor cavity defined by four angular-shaped fixing chips fixed on each of the four inside faces for positioning a PTC resistor therein, and a conductive elastic plate having a plurality of square or rectangular through holes facing toward those in the insulating plates. The elastic plate has an elastic projection on each of the four inside faces of a through hole for pressing a lateral surface of a PTC resistor positioned in a through hole of the position plate after the elastic plate and the position plate have been sandwiched between the two insulating plates.

Abstract: A fluid heater utilizing a porous ceramic, for example silicon carbide, electrically conductive body as an electrically energized heating element to heat a fluid passing through the pores thereof is provided. A plurality of interconnected annular fluid flow passageways are positioned in the fluid heater so that fluid exiting therefrom surrounds the porous body, further improving the efficiency of the porous fluid heater body. An electrical disc rear contactor is positioned within one end of the cylindrical sleeve to peripherally engage the sleeve and axially electrically engage the body. An electrically conductive disc front contactor is positioned concentrically at an opposite end of the sleeve to peripherally engage the housing in electrical contact relationship and axially engage the body in electrical contact relationship.

Abstract: A heating apparatus comprises a closed vessel having thermally conducting walls and containing a gas that is heated by one or more electrical heating elements in the vessel. The vessel is received in a duct through which air is blown. The air is heated by the heat transferred to the vessel walls by the gas in the vessel. Pressure and thermostatic switches in the circuit of the heating element communicate with the gas in the vessel and provide a double-safety, over-temperature power shut-off. The heating apparatus may be used to blow hot air into water in a tub through hoses leading to inlet openings or to an air distribution mat placed in the tub. The bubbles of hot air heat the water and produce strong agitation. A special raft receives the air distribution mat, which heats water in the raft by bubbling hot air through it. The heating apparatus can also be used for space heating, warming and drying towels and clothes, hair drying and grooming animals.

Abstract: Conductive polymer compositions based on polyvinylidene fluoride have improved properties when the polyvinylidene fluoride has a very regular structure which can be characterized by a low head-to-head content in the repeating units. The improved properties include electrical stability when contacted by organic fluids and/or when maintained at elevated temperatures in air. Such compositions which exhibit PTC behavior are particularly useful in the form of self-limiting heaters which are immersed in organic fluds, especially flexible strip heaters for heating diesel fuel before it passes through a fuel filter.

Abstract: An apparatus for heating gases, particularly air, with a heating unit having a mounting part, at least one PTC component, at least one insulating frame part surrounding the latter, at least one contact plate and at least one insulating support. The PTC component is surrounded by the frame part being inserted in the mounting part and on at least one flat side rests a contact plate and is covered by an insulating support. Heat emission lamellas are mounted in a clamping manner on the heating unit to ensure an effective heat emission to the surrounding air or gas.

Abstract: An electrical resistance heater includes interior surface bounding a fluid passage therein configured so as to disrupt lamellar flow of fluid and impart cross-mixing to the fluid. In specific construction, heaters herein include a housing, or heating cartridge insert to the housing, having a fluid inlet port and a fluid outlet port, a fluid passage extending longitudinally with the housing between the fluid inlet port and the fluid outlet port and bounded in part by surface which is configured to impart lateral displacement to fluid traversing the passage, and an electrical resistance heater disposed in such passage.