Abstract: An improved solid heat transfer element composed of an elongate member having a generally cylindrical surface with male vortex generating protrusions is provided. The vortex generating protrusions, which may be referred to as “turbulators,” provide improved heat transfer by convection to a flow of air transverse to the elongate members without substantially increasing the pressure drop in the flow of air passing over the members. Advantageously, a plurality of the heat transfer elements, or of straight portions of a single serpentine heat transfer element, may be arranged in an aligned or staggered array of elements or straight portions. Many advantageous profile shapes of the element and vortex generators are provided, including aerodynamic profile shapes that are symmetrical with respect to a fluid flow to provide low drag and pressure drop. Heat in the element may be generated by means of electrical resistance or absorption of radiation.

Abstract: A positive temperature coefficient (PTC) superimposed impedance polymeric (SIP) compound including an electrically insulating matrix essentially consisting of a siloxane polymer in addition to first and second electrically conductive particles having different properties with respect to surface energies and electrical conductivities. A multi-layered, ZPZ, foil including a PTC SIP compound of the invention present between two metal foils, thereby forming a conductive composite body. A multi-layered device, including an essentially flat composite body made up from a PTC SIP compound according to the invention, two electrode layers adhering to the surfaces of the composite body, the electrode layers being metal foils prepared to connect to electrodes.

Abstract: An electrical assembly includes at least two PTC-resistor elements, each of which has a base body having a flat shape. Each base body has main surfaces that contain electrodes. A carrier plate has spacers for positioning base bodies of the at least two PTC resistor elements. A width each spacer is about equal, in at least one area, to a distance between facing electrodes of adjacent PTC-resistor elements.

Abstract: An electric heating element with radiant tube comprising a radiation pipe (1) and an electric heating element (2, 3) contained in said pipe, wherein the heating element has legs that run to and fro in the pipe, and wherein the heating element is connected at one end of the pipe close to a furnace wall with electric power outlets through which electric current is fed to the element, wherein the element is supported in the pipe by ceramic discs (9) that are provided with through-penetrating holes through which the legs of the elements extend, and wherein two elements (2, 3) are disposed sequentially in said radiation pipe along its long axis.

Abstract: A method of supporting vertically hanging electrical resistance elements for heating furnaces or ovens in industrial operations. Each resistance element includes current-conducting legs that extend downward and upward a number of times, and the element includes along its length a number of ceramic discs that are provided with through-holes through which respective element legs extend. The upper part of the element merges with terminals that are connected to a source of electric current. The element is supported by at least one of the uppermost ceramic discs, wherein the uppermost ceramic disc supporting the element is placed in the insulation of the furnace roof above the underside of the roof. The legs of the element are short circuited at a location slightly or somewhat beneath the underside of the furnace roof with the aid of short circuiting plates.

Abstract: The present invention discloses a manufacturing method of an over-current protection device, characterized in that the PTC plaque is conducted by punching under frozen state to form the over-current protection devices so as to reduce the heating and temperature rising in the PTC plaque due to punching and temperature difference between the metal foil and the conductive composite material. Relatively, the deformation and stress of the over-current protection device caused by punching will also be reduced. Therefore, there is no need for additional process to increase the temperature sensitivity and electrical property stability of the over-current protection device.

Abstract: An inexpensive positive temperature coefficient thermistor has metal terminals which have been miniaturized without deteriorating the characteristics or sacrificing the reliability of the device. The metal terminals include supporting members and springs constructed such that a total width of the supporting members is smaller than a total width of the springs. In addition, connecting portions at the upper ends of the metal terminals engage with a case main body or a covering member to be retained at predetermined positions.

Abstract: The present invention discloses a manufacturing method of an over-current protection device, characterized in that the PTC plaque is conducted by punching under frozen state to form the over-current protection devices so as to reduce the heating and temperature rising in the PTC plaque due to punching and temperature difference between the metal foil and the conductive composite material. Relatively, the deformation and stress of the over-current protection device caused by punching will also be reduced. Therefore, there is no need for additional process to increase the temperature sensitivity and electrical property stability of the over-current protection device.

Abstract: An electrical device comprising a pair of electrodes, three substrates, and PTC elements inserted between the substrates, each PTC element having metal layers on both surfaces, in which each of the outer substrates has a metal layer on the inner surface, the two metal layers being electrically connected to one of the electrodes and in electrical contact with the respective metal layers of the PTC elements facing said metal layers of the outer substrates, and the center substrate has a metal layer on both surfaces, such metal layers being electrically connected to the other electrode and in electrical contact with the respective metal layers of the PTC elements facing said metal layers of the center substrate. This electrical device can increase the area of the PTC elements without increasing the projected area as a whole.

Abstract: A positive-characteristics thermistor apparatus has an insulating case, positive-characteristics thermistor devices, planar terminals, and spring terminals. Whichever thermistor device has a lower resistance of the two thermistor devices is trimmed to have a higher resistance which is near the resistance of the other thermistor device such that the two thermistor devices have substantially the same resistance (for example, within a difference of ±1 &OHgr;). In other words, a part of an electrode of the thermistor device having a lower resistance is removed with a laser beam.

Abstract: A PCT thermistor arrangement for use in a circuit for demagnetizing shadowmasks of color picture tubes, has at least two PTC thermistor elements which are designed as switching PTC thermistors, are or can be thermally coupled and are or can be electrically connected in parallel.

Abstract: In a surge arrester with a multi-column arrangement of the metal oxide resistors within an insulating housing, each column is to be made of resistance elements in a mechanically self-supporting structure. To this end, the resistance elements of each column are arranged between two holding plates intercon-nected by holding rods. The individual columns, called "modules", are arranged to be individually centered on a plate fitted at the lower end of the insulating housing.

Abstract: An arrester has a plurality of laminated columns arranged in parallel, each having a plurality of nonlinear conduction elements. The columns are electrically interconnected by conductive connection members so that a conduction path is defined by the conduction elements and the connection members. The columns are arranged around, and in contact with, an insulating support column, which provides mechanical strength for the arrester. A plurality of such arresters may be arranged in an array, the arresters being interconnected by further insulating support columns. The laminated columns also contain insulating spacers and the spacers of two or more laminated columns may be rigidly interconnected. The arresters may be mounted in a casing filled with an insulating gas.

Abstract: A gas sensor of the thermal conductivity type suitable for the quantitative analysis of the fuel vapor content of a fuel-air mixture. The gas sensor (10) comprises a sensing element (28) and a compensating element (30), each of which includes an electrically-heated hot member (38) incorporated into a Wheatstone bridge circuit powered by a constant current supply circuit (70). The constant current supply circuit (70) is adjusted and regulated such that the hot member (38) of the sensing element (28) is heated with an electric current of such an intensity that corresponds to a point of transition (Y) at which, at the interface of the hot member (38) and the mixture, the predominant mode of heat transfer changes from thermal conduction to natural convection.

Abstract: A radiant tube heating assembly for a furnace, which assembly combines the features of a heating element utilizing the latest powder metallurgical technology, improved ceramic spacers and staggered weld joints to thereby enable higher efficiency and heating temperatures. Further, the assembly enables a higher temperature element system, ease of manufacture and reduced failures due to shorts or arc over at the weld joints.

Abstract: An elctrical appliance for preparing food is provided which contains several incandescent lamps (2, 2') disposed side by side. Incandescent lamps (2, 2') for use in the appliance have a U-shaped tubular lamp vessel (4) in the first (8) and the second leg (9) of which a first (10), and, a second portion (11) respectively of an incandescent body (5) is accommodated. The first portion (10) consumes a higher power than the second portion (11 ). In the appliance the lamps (2, 2') are arranged with the second filament portions (11 ) adjacent to each other. Thereby, a more homogeneous irradiation of a carrier (3) for food is obtained.

Abstract: A zinc oxide type arrester including: four constitutional units electrically connected in parallel and a closed container accommodating the constitutional units. Each of the constitutional units includes a first columnar stack body composed by stacking zinc oxide elements and insulating spacers in a first predetermined order, a second columnar stack body composed by stacking zinc oxide elements and insulating spacers in a second predetermined order and a third columnar stack body composed by stacking zinc oxide elements and insulating spacers in a third predetermined order, the zinc oxide elements in the first, second and third columnar stack bodies contained in one constitutional unit are connected in series as a whole, and at least two of the three columnar stack bodies having same stacking structures in adjoining constitutional units are arranged to closely face each other.

Abstract: A positive temperature coefficient thermistor device includes an insulating casing housing a pair of positive temperature coefficient thermistors. Each of the inner surfaces of a pair of opposed walls consisting of the side walls and the top and bottom walls of the case is provided with a recess formed of at least one pair of tapered surfaces sloping from the walls provided with a pair of electrodes towards a common electrode located in the center. The thermistors are arranged so that the rim thereof has at least a one-point contact with the tapered surfaces of the recesses.

Abstract: An infrared radiator includes a non-circular jacket tube made of quartz material, which may be quartz glass, the length of which is a multiple of the larger interior diameter and the interior of whch, in a sectional view, is separated into two areas, in each of which a heating wire extends in the direction of the tube axis. The heating wires are electrically conductive and connected to each other at one end of the jacket tube and lead to the exterior via connecting pieces at the other end. Two cross pieces which protrude from the inside wall of the jacket tube face each other and are directed toward the direction of the axis of the jacket tube so as to form the two areas.

Abstract: A grid resistor assembly includes a plurality of flat grid resistor elements. Each element includes at least one open-ended loop having side portions and a tip end portion connected together through intervening strip portions of narrower width than the side portions to improve current carrying capacity and to provide for more even heating and heat dissipation. An assembly of such elements is particularly used as a resistor box in an electric, motor-driven, transit vehicle, such as a subway car, and is provided in a predetermined space envelope to perform predetermined electrical parameters.

Abstract: An electrical infrared radiant heater in which a heater assembly includes an extruded ceramic holder having parallel holes, certain of which receive heating element wires through such holes. The ends of the heating element wires extend outwardly of the holder on both sides and are joined to each other so as to form a resistance element connected to a source of current. A casing carries the heater assembly.