Abstract: An electrical heater utilizes negative temperature coefficient material (NTC) and current imbalance between live and neutral ends of the heater to simultaneously protect the heater from the hot spot and mechanical intrusion into the heating cable. The NTC layer, separating the heating wire and current leakage conductor, becomes electrically conductive at the temperatures above 60° C., thus “leaking” the current to earth. The hot spot is detected by measuring the current imbalance between line and neutral connections of the heating cable. The mechanical intrusion into the heater, such as cable or insulation damage, water or sharp metal object penetration, is also simultaneously measured by the same current imbalance measuring system such as Ground Fault Circuit Interrupter (GFCI). The optional return conductor and metal foil/mesh hot spot detection shields cancel electromagnetic field. The heater may contain positive temperature coefficient (PTC) continuous sensor to control the temperature in the heater.

Abstract: A soft and flexible heater utilizes electrically conductive threads or fibers as heating media. The conductive fibers are encapsulated by negative temperature coefficient (NTC) material, forming temperature sensing heating cables. One or more heating cables can be formed into heaters of various configurations including tapes, sleeves or sheets providing simultaneous heat radiation and local overheat protection. Such heaters may be connected in different combinations, in parallel or in series. The heater may contain continuous positive temperature coefficient (PTC) temperature sensors to precisely control the temperature in the heater. Such temperature sensors can be made of electrically conductive fibers, metal wires or fiber optical filaments. When required by the heater design, the electrically conductive threads/fibers may have a polymer base, which acts as a Thermal-Cut-Off (TCO) at predetermined temperatures. Electrically conductive fibers comprised of such polymer base can melt between 110° C.

Abstract: A soft and flexible heater utilizes electrically conductive threads or fibers as heating media. The conductive fibers are encapsulated by negative temperature coefficient (NTC) material, forming temperature sensing heating cables. One or more heating cables can be formed into heaters of various configurations including tapes, sleeves or sheets providing simultaneous heat radiation and local overheat protection. Such heaters may be connected in different combinations, in parallel or in series. The heater may contain continuous positive temperature coefficient (PTC) temperature sensors to precisely control the temperature in the heater. Such temperature sensors can be made of electrically conductive fibers, metal wires or fiber optical filaments. When required by the heater design, the electrically conductive threads/fibers may have a polymer base, which acts as a Thermal-Cut-Off (TCO) at predetermined temperatures. Electrically conductive fibers comprised of such polymer base can melt between 110° C.

Abstract: A soft and flexible heater utilizes electrically conductive threads or fibers as heating media. The conductive fibers are encapsulated by insulating materials, forming continuous heating cables. One or more heating cables can be formed into heaters of various configurations including tapes, sleeves or sheets. Such heaters may be connected in different combinations, in parallel or in series. The heater may contain continuous temperature sensors to prevent overheating and fire. Such temperature sensors can be made of electrically conductive fibers, metal wires or fiber optical filaments. When required by the heater design, the electrically conductive threads/fibers may have a polymer base, which acts as a Thermal-Cut-Off (TCO) at predetermined temperatures. Electrically conductive fibers comprised of such polymer base can melt between 120° C. and 350° C. thereby terminating electrical continuity in the heater.

Abstract: A soft heating element utilizing individually insulated electrically conductive carbon or metal containing threads/fibers or metal wires that are woven together with nonconductive threads, into sheets, sleeves or strips. The individually insulated conductive threads/fibers or metal wires can be laminated between layers of nonconductive insulation. Nonconductive polymer insulation can be extruded around the non-insulated electrically conductive threads/fibers or metal wires to form strips, sheets or sleeves/pipes. The heating element core is shaped in a desired pattern and connected in parallel or in series to the energizing bus conductors. The thermostats are located in areas of folds in order to control their cycling. When dictated by the heating element design, the electrically conductive threads/fibers have a polymer base, which acts as a Thermal-Cut-Off (TCO) material at predetermined temperatures.

Abstract: A soft heating element, utilizing electro conductive textile threads as a heating means having additional safety functions as TCO (thermal cut-off) and TSL (temperature self-limiting) devices. The thermal cut-off function is achieved through melting of the electro conductive threads at the temperatures above 120° C. and below 350° C., which results in termination of electrical continuity in the heating element. The temperature self-limiting capability is achieved through a heating thread electrical resistance increase during slow elevation in its temperature, which is below its melting point. Methods of electrical and mechanical connection between heating threads and metal conductors, utilizing winding of connections with flexible strands of fibers or wires, with optional subsequent placement of a rigid mechanical fastener over the winding.

Abstract: A soft heater, containing metal, carbon or conductive ink coated textile threads, embroidered on, laminated between or woven into a nonconductive substrate to form electrical heating circuits. The heating element may be manufactured in a form of strip, sheet, sleeve or strand of electrically conductive threads for incorporation into plurality of articles. The heating element is shaped or embroidered in a desired pattern. The embroidered heater may be used for a night vision identification purposes.

Abstract: A soft heater utilizing metal fiber containing, carbon, metal or conductive ink coated threads, embroidered on, laminated between or woven into a nonconductive substrate to form electrical heating circuits. The heating element may be manufactured in a form of strip, sheet, sleeve or strand of threads for incorporation into plurality of articles. The soft heating element core may contain localized treatment such as positive temperature coefficient (PTC) material for temperature self-limiting control. The electrode conductors are attached to said heating element core which is connected in parallel or in series. The heating element core is shaped in a desired pattern. The whole assembly is sealed by at least one electrically insulated layer which envelopes the strips, sheets, sleeves, ropes or strands of threads.

Abstract: A soft and flexible thin heating element made of electrically conductive carbon carrying fabric coated with a soft stabilizing material. The heating element is shaped by curing the soft stabilizing material and cutting the coated fabric into a desired pattern. The electrical contacts are attached to the ends of the heating element core, which are electrically connected in parallel or in series. The fabric heating element core is sealed to form a multi-layer assembly comprising of at least two electrically insulating layers which envelop each strip of the heating element core. A method of producing the soft and flexible heating element is also disclosed.