Abstract: The invention concerns a permanent filter for the preparation of tea in pots or cups, consisting of a filter housing with an upper, ring shaped rim (1) and a fluid permeable straining fabric (3). The special feature of the invention consists in the fact that provision is made in the upper rim (1) for one or more openings (5) for receiving a tab (7) of a lid (6).

Abstract: A heating element, preferably for oblong plate-shaped sensors for measuring oxygen concentration in internal combustion engine exhaust gas, has a conductive heating strip at one end of the heating element and electrical conductors which are connected electrically to the conductive heating strip and which supply the heating current and provide connection to the other end of the heating element. The positive temperature coefficient of the resistor material of the conductive heating strip is lower than the positive temperature coefficient of the material of at least one section of the conductors.

Abstract: An electric multi-stage heater assembly that provides multi-level heating using a plurality of separately controllable heating elements within a housing that is readily interchangeable with standard single-stage heater housings that can be controlled by conventional power switching circuits. The multi-stage heater assembly of this invention has each electric heater element straddling a support member with a portion of the heater element extending from one side to the other to maintain the electrical continuity of the element. The support member has a plurality of cut-outs that provide space for routing the cross over portion of the heater element and sufficient clearance to accommodate the inevitable droop associated with heat cycling electric resistive heater elements. The support member is equipped with a plurality of insulators which support and electrically insulate the heater element. The insulators are arranged to cooperatively rotate within the support member to minimize sagging of the heater elements.

Abstract: An apparatus for warming one or a plurality of tortillas or other unleavened breadstuffs individually, on both sides at once, and simultaneously in a traditional manner. The electric kitchen appliance of this device is efficient and easy to use and meets an unmet and growing need. Also disclosed is a method for use.

Abstract: A pancake maker in which several batter-filled containers are simultaneously placed within a heating device to make pancakes. All the resulting pancakes are uniformly shaped and cooked and can be quickly produced. This invention is applicable to the individual as well as the restaurant industry and greatly enhances the look, consistency, and quality of pancakes made.

Abstract: A composite repair device including a plurality of resistive heating zones, each having independent temperature and rate of temperature rise controls, to compensate for the greater heat loss at the outer areas of a composite patch.

Abstract: A surface-unit cooking appliance comprising a plurality of electric hot plates of the same type, each of the hot plates having a temperature regulator and each of the regulators having a temperature sensor for sensing the temperature of a cooking vessel or a product being cooked, at least one of the hot plates being disposed in each of first and second surface cooking zones, the first zone being designed for boiling water-containing media, the at least one temperature regulator therein being designed and constructed with a temperature control range limited to a maximum temperature of 150.degree. C. (300.degree. F.) at the temperature sensor, and the second zone being designed for roasting, the at least one temperature regulator therein being designed and constructed with a temperature control range limited to a maximum temperature above 220.degree. C. (430.degree. F.) at the temperature sensor.

Abstract: An apparatus is disclosed for melting asphalt and for maintaining it in a molten condition without producing by-products harmful to the atmosphere. The asphalt is heated and maintained in a liquid state in an enclosed vessel by transferring heat from a heating means through inner wall portions of the vessel. Air polluting by-products are minimized due to the increased surface area heating the asphalt and the resulting reduced thermal gradient which prevents decomposition of the asphalt. A control system for selectively controlling the heating of the asphalt in a manner which reduces the production of air polluting products is also disclosed.