Abstract: A filter unit (10) for removing particulates from exhaust gases for example from a diesel engine, includes several filter elements (24) arranged so the gas flows through them are in parallel and that no individual element carries more than a fifth of the total flow. Each element (24) comprises a tubular heating element (50) of high voidage electrically conducting material, with a secondary filter layer (52) adjacent to its upstream surface, and with means (53-63) to ensure the gas flow and particulate deposition are substantially uniform over the upstream surface. At intervals the heating elements (50) are electrically energized, in turn, to burn off deposited particulates. At any one time only a subset of the elements (24) is energized through which at that time no more than a fifth of the total gas flow passes. The unit (10) might have thirteen such elements (24), energized one at a time.

Abstract: A heating element comprises a body provided by fibrous tubes of an electrically conductive material, a voidage between the tubes providing a path for a fluid to be heated. The material may be silicon, silicon carbide, or silicon rich-silicon nitride. The heating element is manufactured by coating a fibrous carbon precursor with the material, and heating the coated precursor in an oxidizing environment so as to remove the carbon precursor by oxidation. The heating element has one application for a heat transfer system for controlling the temperature of a hot working device. The system comprises a fluid circuit including the hot working device, the heating element through which the fluid is driven by a pump, and a temperature controller for sensing the temperature of the device and controlling the temperature of the heating element as a function of the device temperature.

Abstract: A method of gas ignition comprises energizing a permeable, porous electric heating element to an appropriate temperature for igniting a gas, and allowing the gas to contact the heating element.

Abstract: A panel, which may form a wall or a door (12) of a fire resistant cabinet (10), consists of an outer casing (16, 26) and an inner panel (14, 24) spaced apart by zig-zag shaped bridging members (20, 22, 28). The inner panel is double-walled and contains a material which undergoes a phase change at a temperature below that at which the contents of the cabinet might suffer damage. The space between the outer casing and the inner panel contains a number of metal foils (32, 34) parallel to the outer casing which acts as radiant heat shields. The bridging members may be of ceramic material of low thermal conductivity, and may be slotted to increase their resistance to heat flow.

Abstract: A thermal insulation layer, suitable for use in a duvet, comprises a convection inhibiting structure and at least one surface with a low thermal emissivity. The structure may be a flexible cellular foam sheet or a web of fibrous material, while the low emissivity surface may be a coating on the sheet or on a thin flexible thermally insulating film. Perforations are provided through the foam sheet or the film to permit diffusion of water vapour through the layer, and the layer may include an additional web of fibrous material or feathers adjacent to the low emissivity surface.

Abstract: An apparatus or a method for heating a component by the condensation thereon of a suitable vapor, for example to make a soldered connection in condensation soldering. The vapor is produced by passing a heat transfer oil through a vaporizer comprising permeable electrically conductive material, and is introduced into a heating chamber containing the component. The heating chamber is held at a pressure below atmospheric pressure, and a condenser chamber is connectable to the heating chamber for condensing the vapor at the end of the heating cycle.

Abstract: An apparatus or a method for heating a component by the condensation thereon of a suitable vapor, for example to make a soldered connection in condensation soldering. The vapor is produced by passing a heat transfer oil through a vaporizer comprising permeable electrically conductive material, and is introduced into a heating chamber containing the component. The heating chamber is held at atmospheric pressure by a bellows connected to the heating chamber.

Abstract: A method of manufacturing a fluid permeable electrical resistance heater element having a structure that promotes uniformity of flow of fluid through the element and a uniformity of heating throughout the element. The method comprises forming a fluid permeable body of unbonded carbonizable fibres. A latent solvent is applied to the fibres and the solvent is subsequently caused to dissolve at least a surface of the fibres so as to effect bonding of the fibres together. The carbonizable fibres are subsequently carbonized to produce a fluid permeable carbon body.

Abstract: The invention relates to thermally insulating, fire resistant material and its production.A problem associated with fire resistant material comprising refractory material and a binder is the tendency, in use, of the material to disintegrate due to bond failure. In the invention, hollow particles of a glass or of a ceramic are combined with a binder to give a material where the proportions of binder are such that the material is capable of deformation at high temperatures (e.g. up to 1100.degree. C.) without fracture or loss of cohesion. A specific example consists of 93% by weight of hollow spherical particles of pulverized fuel ash and 7% by weight of sodium silicate binder. The material is particularly useful in the protection of steel structures.