摘要:
A heat-sensitive resistive compound is formed by a mixture of particles of at least one electrically conducting material (A) in the solid state and of at least one resin (B) in the solid state; the mixture is dispersed in at least one liquid solvent (C); the percentage by weight of the electrically conducting material (A) with respect to the total weight of the anhydrous compound is 5% to 70%. The resistance of the compound after a furnace process increases, as the temperatures rises, in a substantially linear manner for temperatures that are approximately lower than or equal to 70.degree. C. and in a substantially exponential manner for temperatures that are approximately higher than 70.degree. C. The relative increase in the resistance of the compound with respect to its resistance at ambient temperature is at least 3 for temperatures higher than 100.degree. C. and at least 5 for temperatures above 115.degree. C. The method for providing a PTC device includes the deposition, by printing or screen-printing, of the resistive compound on a flexible or rigid laminar support made of insulating material (2) along an electric path (3) that connects conducting paths (6) which form electrodes; the compound is deposited when cold and is subjected to one or more furnace processes at a temperature that is at least equal to 110.degree. C. for a period and a number of times that are sufficient to achieve the complete evaporation of the solvent (C) and the adhesion of the resin (B) to the substrate.
摘要:
In an electrical dispenser (10) for deodorant or insecticide which contains electric heating means (40) placed near the first end (76A) of a wick (76) the second end (76B) of which is dipped into a deodorant or insecticide liquid (72) contained in a small bottle (70), the electric heating means (40) consist of a resistive heating strip (40) wrapped around the first end (76A) of the wick (76).
摘要:
A device for rapidly defrosting a refrigerator compartment, such as a freezer compartment or the like, said compartment comprising a plurality of adjacent walls, in correspondence with at least one of said walls there being arranged a hairpin coil evaporator for a static refrigerator, or a part of an evaporator of forced-air type, within a refrigeration circuit comprising a motor-compressor unit, said device comprising heating means arranged in correspondence with at least one of said walls and/or with the evaporator, said heating means being electrically powered via an electrical supply circuit associated with the refrigerator; the heating means are at least one resistance element of PTF (polymer thin/thick film) type.
摘要:
A compact immersion heater, for aquariums, includes: a watertight tubular container (2); an electric heating component (4); an adjustable thermostat (3); an electric circuit (6, 7, 8, 9) for connecting the heating component, arranged in series to the thermostat, to an external electric power source. The heating component is mounted in a radially offset and longitudinally superimposed position with respect to the thermostat and is accommodated in a torus-like gap formed between the thermostat and the inside surface of the container. The heating component is a resistive component having a laminar structure formed by a layer (16) of an electrically resistive material that is anchored to an electrically insulating and heat-resistant flexible laminar support (15). The layer of resistive material is a PTC ink that is printed onto the support in selected regions (17) that are connected to paths that conduct the electric power supply, directly face the sensitive part of the thermostat, and are adjacent to it.