Abstract: The present invention provides a low mass, flexible heat transfer member which is made of a suitable material to transfer heat, as well as a plurality of independent heat generating members to provide zoned heat along a portion of the length of said heat transfer member. The heat generating members are encased in an electrical insulation material which is secured to the heat transfer member. The consolidated structure, i.e. the heat transfer member and heat generating members constitute a flexible strip. The ends of said flexible strip are actually sections of the heat transfer member and these ends are respectively looped around two pins, or studs, and over the respective loops there is positioned an associated slotted hollow tube. The slotted hollow tube is formed to be located in a base of a machine with which the flexible heating means is used.

Abstract: The circumferential wall of the godet drum is heated via air which is heated by a heating device within the chamber of the drum. Air circulation through a closed path is aided by means of fan blades which are mounted on an interior face of the drum.

Abstract: A cordless flatiron includes a sole plate with an exposed bottom surface forming an ironing surface and a top surface including a number of projections extending upwardly therefrom. A protective hood attached to the periphery of the top surface of the sole plate forms an evacuated, sealed chamber thereabove and a heat storage element is positioned in the chamber so as to be movable toward and away from the projections of the sole plate. The heat storage element is heated by an electric heating rod extending therein. A temperature responsive regulator element positioned between the heat storage element and the top of the sole plate and responsive to the temperature of the sole plate is arranged by its configuration to position the heat storage with respect to the upper ends of the projections of the sole plate and thus determine whether or not heat is conducted from the heat storage element to the projections of the sole plate and to the ironing surface of the sole plate.

Abstract: A heating element comprises an electrically nonconducting support body having a pair of opposite faces and formed with a plurality of throughgoing holes opening at the faces, respective electrically energizable heating capsules in the holes and each having one end exposed at one of the faces and an opposite end exposed at the other of the faces, and a pair of respective conductors lying on the faces in electrical contact with the respective exposed ends of the capsules. A tight hermetic skin surrounds and encapsulates the body with the capsules in the holes and the conductors on the faces. A pair of respective wires extending through the skin and connected to the conductors serve for passing electricity through the heating capsules. The skin effectively protects the assembly from moisture when installed in a heater. In addition this skin protects the heating element prior to installation and can in fact eliminate the need for a shipping package.

Abstract: An electrical heating device is disclosed for heating a plate which, for example, is used for heating the outside rear view mirror of a vehicle. The heating device includes a positive temperature coefficient resistor constructed as a resistive body in the form of a flat cylindrical ring. One flat surface of the ring is seated upon the plate to be heated which is used as one electrical terminal of the resistor. Another metal plate is seated against the other flat surface of the ring and serves as the second electrical terminal and also as a heat distributing plate for the resistive body. A two part fastening means comprising a headed shank and a press-on nut is provided, with the shank extending through the plates and the resistive body to press them against one another to obtain good electrical and thermal conduction.

Abstract: A planar heat generating device is made up of two heat radiating plates having through-holes, heat generating units of positive temperature characteristic material held between the two plates, two lead wires connected to the two plates, and an insulating cover layer of heat resisting synthetic resin which covers the two plates, the heat generating units and the connecting points of the lead wires. Fluid through-holes are formed in the parts of the insulating cover layer which are applied to the through-holes of the plates, so that the heat generated is effectively conducted to the fluid.

Abstract: A device to melt ice and snow on a roof structure to provide channels for the drainage of water, the device being an elongated, rigid structure having a hinged end portion to extend over a gutter, having means in connection with the other end portion thereof to removably support the same, the device being formed of a highly conductive material having heating cables in contact with the outer structure thereof for heat transference and having a plurality of apertures in the upper surface thereof, the device being particularly designed to be installed either upon a dry roof or upon a snow or ice covered roof.

Abstract: An electric heat exchange cooking unit for use, selectively, with any one of a plurality of different cooking receptacles, has a heat exchange member including locking mechanism for mechanically constraining the flat undersurface of the cooking receptacle in intimate face to face contact with the top, flat surface of the heat exchange member upon the selected cooking receptacle being fully locked in place. The heat exchange member is of cast metal having embedded therein a continuous electrical heating element of such configuration as distributes heat substantially uniformly throughout the upper surface of the heat exchange member while at the same time providing a central opening within which is received a remote-indicating temperature sensor for measuring the degree of heat being uniformly applied to the food being cooked in the selected cooking receptacle.

Abstract: A self-regulating heater for use in an early fuel evaporation system for an automotive engine includes a metallic radiator having a first heat-receiving side and an opposite side for transferring heat to a fuel evaporization zone. Self-regulating ceramic electrical resistance heater elements having a positive temperature coefficient of resistivity(PTC) are disposed with first sides in facing relation with respective recessed first portions of the heat-receiving side of the radiator. A thermally conducting metal heat-transfer member has recessed first portions disposed in facing relation to respective second sides of the heater elements to receive heat second sides of the heater elements to receive heat from the second sides of the heaters and also has second portions disposed in closely-spaced facing relation to corresponding second portions of the heat-receiving side of the radiator, thereby to transfer the heat received from the second heater sides to the radiator.

Abstract: This invention relates to an improved method of making a sprue bushing for injection molding and the improved sprue bushing made thereby. The runner passage extends through a corrosion resistant inner core portion with an outer surface around which a helical electrical heating element is located. A stainless steel outer sleeve extends between an enlarged front portion which provides the opening to the gate and an enlarged back collar portion which provides for connection to the heating element leads. The space around the heating element is filled by a highly conductive material such as a beryllium copper alloy in a vacuum furnace which causes the beryllium copper to fuse with the adjacent materials. This improves the transfer of heat from the heating element to the melt and the outer sleeve substantially reduces the costly machining required to produce the finished product as well as provides additional strength.

Abstract: A heater unit is provided for activating a heat sensitive adhesive binder system. The unit has simplified control and indicator means.

Abstract: An incubating device particularly adapted for aligning an array of microscope slides bearing a tissue section, sample or specimen, and incubating the same with a series of test or reagent solutions at a higher-than-ambient temperature, is disclosed. The incubating device has a main body including a recess which substantially forms a tray in the main body. A plurality of substantially regularly spaced metal blocks are disposed in the recess, and a substantially flat upper surface of each metal block is adapted to receive and be in contact with a respective microscope slide.A heater is mounted underneath the main body to heat the main body, and to affect by direct conductance of heat, the heating of the metal blocks. A thermostat is mounted to the main body to monitor the temperature of the main body and to regulate the output of the heater in response thereto whereby the temperature of the metal blocks is maintained in a desired predetermined range.

Abstract: This invention relates to an integral heated probe for plastic injection molding and a method of making the same. The probe has an elongated steel outer body with a cylindrical well extending to a pointed tip end. An electrical cartridge heater member positioned in the well with the leads extending out the open end. The space adjacent the pointed tip end and all around the cartridge heater is filled with copper to improve heat transfer between the heater member and the outer body. The copper fusing is performed by two-stage heating in a vacuum furnace. First a slug of copper is inserted into the well and heated to melt it into the pointed tip end. Then the heater member is inserted into the well through a sleeve of copper at the top and heated to melt the copper. The copper flows down around the heater member and fuses to it, the outer body and the previously inserted copper.

Abstract: A semiconductor integrated circuit supporter on which a heating element is dielectrically provided, said supporter comprising a package, printed circuit board, mother board, etc. for supporting a semiconductor integrated circuit which includes devices such as transistors.The heating element provided on said semiconductor integrated circuit supporter is capable of heating the whole or a required part only thereof so that the semiconductor integrated circuit is preheated to a temperature required for its normal operation with precision and stability thereby improving the accuracy and reliability of various devices of which a semiconductor integrated circuit is composed as well as the control by said devices.

Abstract: A nozzle for use in an injection molding machine. The nozzle comprises a tripartite body having an inlet, an outlet and an interconnected passageway extending therethrough. A heat pipe is located within the center of the body and portions of the passageway are disposed about the heat pipe. A resistance heating band is mounted on the body to conduct heat therethrough to heat the heat pipe. The heat pipe serves to heat plastic flowing through the surrounding passageway portions to the outlet.

Abstract: A thermal energy transfer apparatus and method to efficiently transfer thermal energy between two or more media, such as plural fluids, a fluid and a solid, two solids, etc. A thermally conductive mesh-like member provides relatively large surface areas for energy transfer therethrough. In one embodiment the mesh-like member disperses a fluid flowing therethrough while simultaneously effecting efficient and substantial thermal energy transfer therewith. A pair of thermally conductive generally solid discs direct the fluid into and receive fluid from the mesh-like member while also distributing thermal energy in the mesh-like member and/or transferring thermal energy with respect to the latter, for example, to a source or dissipator of thermal energy.

Abstract: A refrigeration evaporator includes a serpentine refrigerant tube having a plurality of finned straight portions connected by unfinned U-shaped connecting portions to form a stacked assembly of side-by-side finned tube arrays. The fins are rectangular and are provided with a J-shaped cut-out at each corner. The J-shaped cut-outs at confronting corners of the fins of each immediately adjacent pair of finned tube arrays define a U-shaped heater receiving space extending the length of the arrays and which clampingly receives an elongated straight portion of a serpentine electric defroster heater in good heat conductive contact with each fin of the immediately adjacent pair of finned tube arrays. Each fin of the stacked assembly has at least two corners in engagement with the heater. The stacked assembly is disposed transversely in a duct having an air inlet and air outlet.

Abstract: A flat, normally horizontal electric resistance blanket heater comprising a thin, fragile elongate resistance element on one surface of and carried by a thin, flexible sheet of dielectric material, a thin, flat resilient and flexible reinforcing strate of dimensionally stable material retained adjacent the other surface of the film to permit flexure of the heater and without dimensional distortion of the film and element and a flexible envelope encapsulating the sheet element and strate.The heater also includes temperature responsive switching means responsive to the temperature of heated portions of the heater and in temperature insulated relationship from a portion of the heater where the element connects with power supply lines and which creates a portion in the heater of increased mass and heat storing capacity.

Abstract: Electric heater assemblies to encircle and warm hermetic compressor housings are fabricated by the selection of a sheathed tubular heating element of a length of the same order of magnitude as the circumference of the compressor housing to be encircled and a bend is introduced near the end of the selected element. An elongated tensioning member and the element bend are positioned closely adjacent one another and a mass of non-metallic material molded about the element bend and a portion of the tensioning member to join the member to the selected element. Opposite ends of the tensioning member may be joined to the heating element near the opposite ends thereof by introducing a similar bend near the end opposite the one end of the selected element and similarly juxtaposing the tensioning member and bend and thereafter molding a further mass about the element bend and tensioning member so as to form a loop for encircling the housing.

Abstract: An elongate flexible package (10) adapted to contain and either enhance or contribute to the control of the heating efficiency of an elongate heating element contained therein and having sufficient flexibility to conform to the item to be heated to which it is secured. Package 10 is provided with a first layer (1) made from a flexible heat conductive or heat insulative material and a second layer (2) made from a heat insulative material that is secured along the length of package 10 to the side of first layer (1) that faces away from the item to be heated to which package (10) is secured. A third protective layer (3) is disposed over second layer (2) and a cavity (4) enclosed by a portion to the walls of layers (1), (2) and (3) extends along the length of package (10) having a cross-sectional configuration adapted to contain and permit the heating element to be axially inserted into or removed from package (10) without having to remove package (10 ) from the item to which it is secured.

Abstract: A cast magnesium oxide based structure is utilized as a heat storage material. In preferred embodiments, the magnesium oxide heat storage material is cast directly about a source of heat. In another embodiment, a block of cast magnesium oxide based heat storage material is placed in contact with a source of heat forraising the temperature and storing heat and later moved to a different environment for transferring heat to that environment.

Abstract: An electrical resistance water heating device, particularly intended for use in coffee or other beverage preparation machines, includes a solid metal heating plate having planar upper and lower surfaces. A fluid throughflow duct is formed between the upper and lower surfaces and includes at least two elongated, spaced, side-by-side branches having corresponding ends interconnected by a connecting conduit to form a continuous fluid flow path from a water inlet to a water outlet. An elongated slot is formed between each pair of side-by-side branches and at least one plate-shaped planar PTC heating element is accomodated within each elongated slot with each of the opposing surfaces thereof directed toward a respective one of the pair of side-by-side branches between which the duct is formed. The spaces between the heating element and walls of the slot are filled with a hardenable electrically insulative filling of good heat conductivity.

Abstract: A device and method for converting electrical energy into heat energy including a cascade connection of bidirectional thyristors, such as triacs, operated from an alternating current power supply. The thyristor are submerged in oil which is thermally conductive but electrically insulative, the oil being in initimate contact with the thyristors junctions. The heat energy at the junctions flows to the oil, from there to a heatsink (radiator), and from the radiator to the surrounding atmosphere.

Abstract: An aquarium heater includes a tubular glass housing provided with a temperature control circuit in the upper part thereof for switching on and off a heating element disposed in the lower part of the housing and comprising an elongated non-metallic support tube on which a helical resistance heating wire is wound. A temperature responsive bimetallic breaker switch enclosed in a metallic housing is coupled within a feed line to the heating wire and is located in the interior of the support tube slightly below the upper end thereof and extends within a number of turns of the heating wire, with length of the breaker switch representing a small fraction of the length of the support tube.

Abstract: The method and apparatus disclosed herein provide a stratified heat bath for use in the heating stage of thermoplastic deformation. It allows for heating of central sections of the thermoplastic lengths in order to render said lengths susceptible to deformation without heating the end sections or tangents of said lengths, permitting the ends to retain their original shape. In the case of tubular lengths, such as lengths of PVC pipe, the invention provides for more rapid heating than in the prior art.

Abstract: A thermic developing station for recording material which is to be developed by means of heat, comprising a rotatable drum and a heating element which is adapted to fit the curvature of the drum surface, the recording material being fed through between the drum and the heating element by the drum and at the entrance of the recording material into the heating zone an unheated member is provided which is also adapted to fit the surface of the drum.

Abstract: An aquarium heater including a housing and a tube depending therefrom. An electric heating element is disposed in the bottom portion of the tube and a thermostatic control chassis is disposed in the upper portion of the tube. The control chassis includes two opposing housing sections matingly engaged in a nesting relationship to form a cylindrical housing unit which snugly fits into the tube and supports a bimetallic thermostatic switch together with associated circuitry and lead wires such that the thermostatic circuit elements are maintained securely positioned within the tube. The housing includes a gasket situated between a lip of the tube and the bottom wall of the housing, and a locking ring which clamps the rim of the tube in place. The tube is thereby held securely to the housing independently of the control chassis.

Abstract: An elongate flexible package (10) adapted to contain and either enhance or contribute to the control of the heating efficiency of an elongate heating element contained therein and having sufficient flexibility to conform to the item to be heated to which it is secured. Package 10 is provided with a first layer (1) made from a flexible heat conductive or heat insulative material and a second layer (2) made from a heat insulative material that is secured along the length of package 10 to the side of first layer (1) that faces away from the item to be heated to which package (10) is secured. A third protective layer (3) is disposed over second layer (2) and a cavity (4) enclosed by a portion to the walls of layers (1), (2) and (3) extends along the length of package (10) having a cross-sectional configuration adapted to contain and permit the heating element to be axially inserted into or removed from package (10) without having to remove package (10 ) from the item to which it is secured.

Abstract: A heater band formed of an extruded metal channel member and a heater plate assembly received within a slot extending along the length of the channel. The heater plate assembly and the extrusion are compressed together to provide a heater band having a dense cross section resulting in improved heat transfer characteristics. The heater band in accordance with the present invention has a longer life and higher heating capabilities than heater bands known to the prior art.

Abstract: An apparatus for liquefying meltable material comprises a container adapted to be filled with the material to be liquefied. The container has a heavy bottom wall formed with closely adjacent perforations which taper in downward direction. The sum of the open cross-section of the perforations at the upper face of the bottom wall is only slightly smaller than the total area of the latter, whereas the sum of the smallest cross-sections of the perforations is only a small fraction of the total area of the bottom face of the bottom wall. The bottom wall is heated by electrical heating elements located in ribs separating the perforations from each other to a temperature to liquefy the material passing from the container into the perforations and the liquefied material flows in a collecting trough arranged below the container and separated by a heat insulating layer therefrom.

Abstract: A heat exchanger for a convector heater includes a tubular heat source and fins for assisting the transfer of heat from the heat source. The fins are arranged in two banks, and the banks are disposed in Vee formation. Preferably the fins are provided with stabilizing strips at their free ends and the heat source is a sheathed electric heating element.

Abstract: A thin, flat, multi-laminate resistance heater structure including a pair of spaced laminates of dielectric material with opposing inner surfaces, an elongate resistance element arranged between and extending throughout the major surface areas of said opposing surfaces, bonding material about the element and between the element and between the laminates and a filler in the bonding material comprising a multiplicity of strong dimensionally stable particulate components of a dielectric material having a lower dielectric constant than the bonding material.

Abstract: A tubular jacket heater having a C-wise radial cross section with an aperture extending in a parallel direction to the axis is proposed which is used to envelop and preheat a tubular lamp used, for example, in a electrophotographic copying machine. The heater is composed of an inner layer made of an electrically insulating rubbery elastomer, an outer layer also made of an electrically insulating rubbery elastomer and a flexible heater element sandwiched by and entending between the inner and the outer insulating layers. The rubbery elastomer recommended is a silicone rubber with a specified hardness.Different from conventional similar tubular jacket heaters in which the insulating layers are made of a rather rigid plastic resin such as a polycarbonate resin, the inventive heater has an excellent adaptability to the outer surface of the tubular lamp inserted therein so that a greatly improved efficiency of the heater is obtained.

Abstract: A heat absorbing and reflecting disc-shaped device having a flat top and a convex bottom and an irregular radially inward-extending cut-out and a plurality of randomly spaced throughbores, said disc being removably mounted on an electric range between the electric coil and reflector pan and resting on the latter. The device is preferably formed from a predetermined mixture of sand clay, water and sodium silicate and may be glazed, if desired. An irregular generally diamond-shaped central opening, preferably, is provided.

Abstract: A thermostatically controlled heater for heating metal work pieces to within a selected temperature range prior to and during a welding process is disclosed. The heater comprises an electric heating element thermally connected to a heat conductive shoe and electrically connected to a source of electric power via a thermostat assembly. The thermostat assembly includes a heat conductive housing mounted on the heat conductive shoe in intimate thermal contact. The housing contains a thermostat having a thermal sensing area in thermal contact with an area of the heat conductive housing for regulating the amount of electricity conducted to the electric heating element. Accurate control of the temperature of the workpiece is accomplished by constructing the heat conductive housing so that the temperature gradient between the shoe and the thermostat matches the temperature gradient between the shoe and the workpiece itself.

Abstract: A flat normally horizontal electric resistance blanket heater comprising a thin, fragile elongate resistance element established on one surface of and carried by a thin, flexible film of dielectric material, a thin, flat resilient and flexible reinforcing strate of dimensionally stable material retained adjacent the other surface of the film to allow for controlled flexure of the heater and prevent dimensional distortion of the film and element and an envelope of flexible dielectric plastic film encapsulating the film, element and strate.The heater also includes temperature responsive switching means responsive to the temperature of heated portions of the heater and in temperature insulated relationship from a portion of the heater where the element connects with power supply lines and which creates a portion in the heater of greater mass and heat storing capacity.

Abstract: The invention relates to an improved frying pan providing good thermal contact between the pan bottom and the heating element, the device comprising a pan adapted with threaded studs to the underside thereof, a support plate adapted with a depression shaped to hold a heating element and further adapted with holes for engaging the support plate on the studs, whereby when locknuts are tightened onto the studs, all parts of the heating element are subject to compression.

Abstract: An electric fry pan in which the pan is formed from cast iron to the underside of which a heat sink of aluminium is secured by mechanical means, the heat sink making close physical contact with a major portion of the underside of the pan. The electric heater element is associated with the heat sink and has connected to it an electrical connector by means of which the heater element may be connected to an electricity supply.

Abstract: An aquarium heater including a housing and a tube depending therefrom. An electric heating element is disposed in the bottom portion of the tube and a thermostatic control chassis is disposed in the upper portion of the tube. The control chassis includes two opposing housing sections matingly engaged in a nesting relationship to form a cylindrical housing unit which snugly fits into the tube and supports a bimetallic thermostatic switch together with associated circuitry and lead wires such that the thermostatic circuit elements are maintained securely positioned within the tube. The housing includes a gasket situated between a lip of the tube and the bottom wall of the housing, and a locking ring which clamps the rim of the tube in place. The tube is thereby held securely to the housing independently of the control chassis.

Abstract: An expansion joint for metallic foil strip heaters encasing resistive heating elements comprised of a bend formed in the metallic foil strips. The expansion joint is formed by use of a tool for passing a roller in the tool handle over a rigid forming support affixed to the tool bottom forming plate with the metallic foil strip heater placed between the roller and the forming support. The tool is then removed and a flexible metal support hose is affixed to the object to be heated with the bend in the metallic foil strips placed over this support hose. The bend is then affixed to the object to be heated on either side of the support hose.

Abstract: A plastic injection molding system having a temperature controlled electric heater element.The heater element is formed by disposing a pair of heater wires and a pair of thermocouple wires and a powdered mineral material in a metal sheath which is subjected to repeated drawing and annealing operations and is then cut to a desired length after which at one end, the heater wires are welded together and the thermocouple wires are welded to the sheath and the sheath is welded to form a closed end wall. At the opposite end, the heater and thermocouple wires are connected through connection means and connection wires to a current supply and a temperature sensing circuit. The sheath is in the form of a rightly wound helical coil structure and is installed in direct heat transfer engagement on a cylindrical surface of a metal part which has an axially extending plastic flow passage therein.

Abstract: An apparatus for storing electrically generated heat includes a sealed container holding a bed of fusible heat storage medium, such as an alkali metal hydroxide composition, and having an expansion space above the bed of material to accommodate the medium in its liquid phase. A generally horizontal main electric heating unit is located in the bottom portion of the container for heating the fusible medium above its melting point. A first vertical electric heater is provided in the bed of material in thermal contact with the main heating unit and has its active heating portion extends upwardly from the main heating unit only to the height of the heat storage medium in solid phase. A second vertical electric heater is located in the container in thermal contact with the first vertical heater with the active heating portion of the second heater extending only from the height of the fusible medium in solid phase to the height of the medium in the expanded liquid phase.

Abstract: A vapor transfer griddle unit with a planar sheet metal heat conductive top member defining a horizontally extensive griddle, a bottom wall sealed to the top member and defining therewith a corresponding vapor chamber disposed below the griddle, a body of vaporizable heat transfer medium in liquid state partially filling the chamber with a vapor space between the surface of the liquid and the griddle at rest as well as over the range of griddling temperatures, a horizontally extensive electric heating array comprised of horizontally spaced electric heater tube portions extending directly beneath and spaced below the griddle and located above the bottom wall, and a set of griddle supports mutually arrayed with the heater tube portions and extending between and engaging the griddle and the bottom wall to provide a pattern of support across the underside of the griddle to maintain the griddle flat over its range of operation, the supports having openings permitting free self-leveling flow of liquid as well as fr

Abstract: A heat storage article adapted for prevention of stratification of incongruently melting heat storage materials, such as eutectic salts, and adapted for use with congruently melting heat storage materials, such as paraffins. The article is comprised of a concrete stone composition, a certain portion of which is comprised of metallic heat transfer materials in order to increase heat transfer through the concrete structure. The concrete structure has an internal cavity which is filled with either the eutectic salt material or the paraffin material.

Abstract: A heat-pressure fusing apparatus that exhibits high thermal efficiency is disclosed.

Abstract: This invention relates to an improved electrically heated sprue bushing for injection molding. The sprue bushing has a central runner passage for conveying melt from the molding machine or manifold to the cavity. The runner passage extends through an elongated inner core portion having an undulating outer surface in the form of a helical ridge with a rounded cross section. A single element electrical heating element with a helical configuration is located over the core portion and an outer shell portion is cast over them to form the sprue bushing as an integral unit. The inner core portion is formed of a high strength material such as a beryllium nickel alloy and the outer shell portion is formed of a highly conductive material such as a beryllium copper alloy. The coils of the heating element are separated from each other and threaded in the opposite direction to the helical ridge on the outer surface of the core portion.

Abstract: An expansion joint for metallic foil strip heaters encasing resistive heating elements comprised of a bend formed in the metallic foil strips. The expansion joint is formed by use of a tool for passing a roller in the tool handle over a rigid forming support affixed to the tool bottom forming plate with the metallic foil strip heater placed between the roller and the forming support. The tool is then removed and a flexible metal support hose is affixed to the object to be heated with the bend in the metallic foil strips placed over this support hose. The bend is then affixed to the object to be heated on either side of the support hose.

Abstract: An immersion heater is disclosed having a heating member with a small thickness and comprised of PTC thermistor material. The heating member has the same heat contact between each of its two major surfaces and the medium to be heated. A Curie temperature T.sub.C and a specific resistance .rho..sub.T.sbsb.C of the material are dimensioned such that with a given operating voltage U a temperature regulation for the range with the positive temperature coefficient of the material results. By use of the upper limit of the Curie temperature T.sub.C, extensive protection against fire can be obtained in the case of inappropriate handling of the immersion heater.

Abstract: An internally heatable nozzle provided with a divisible housing having a cylindrical bore narrowed at one end towards the mouth opening of the nozzle in which bore a cylindrical core is connected at one end in said housing, said core being divisible in transverse direction, its two parts being provided with directly adjacent flanges, which flanges have throughgoing axially channels lying in the extension of the annular channel of the housing and which flanges fit in between inner shoulders on the two parts of the housing, between which parts tensile elements are operative tightening the core parts together, the core being conical at one end and being provided with an internal heating element with connecting leads passed laterally through said housing, an annular channel being arranged between said core and said housing on the side remote from the mouth opening.

Abstract: The apparatus comprises a turntable carrying, in a circular array centered on a central rotational axis of the turntable, a plurality of vials extending below the underside of the turntable. A stepper motor imparts stepwise rotational motion to the turntable so that during dwell periods of the turntable, specimens in the vials can be investigated optically.Air in a space below the turntable and bounded laterally and at the bottom by an enclosure is circulated by a rotating vane, and a thermistor, responsive to the temperature in the region of the vials, controls a heater in the space below the turntable so as to maintain the temperature of the vials substantially at a predetermined value.