GB1029775A - Gas-fired infrared burners and heaters - Google Patents

Abstract

1,029,775. Radiant burners. HUPP CORPORATION. Dee. 16, 1963 [Sept. 3, 1963], No. 49531/63. Heading F4T. An infra-red burner comprises an apertured re-radiating member 162 surrounding an apertured primary radiant member 158, the exterior surface area of the re-radiating member being at least twice that of the primary radiant member. The burner is fired with gas or liquid fuel vapour. The primary radiant member 158 may be made of ceramic plates or wire screens or Inconel and its shape may be hemispherical, or frusto-conical as shown, or it may be a flat disc. A baffle 160 closes the upper end of the frusto-conical radiant member. The fuel/air mixture passes through the primary radiant member and burns on the outer surface thereof. The re-radiating member 162 is made of Inconel sheet or wire and consists of a cylindrical sleeve having a conical or hemi-spherical, perforate or imperforate cover 164. The vent holes in the re-radiating member are preferably but not necessarily uniformly distributed. The total area of the vent holes in the re-radiating member is seven times the total area of the vent holes in the primary radiant member. The vent holes may be perforations of 0À033 in. diameter or they may be slots lanced through the re-radiating member, the metal being sheared outwardly to form louvres, Figs. 18, 19 (not shown), or the re-radiating member may be made of expanded metal, Figs. 20, 21 (not shown). Six large holes 174 are provided in the re-radiating member to permit lighting of the burner. A cross formed by plates may be inserted inside the re-radiating member to divide the interior thereof into four quadrants, Figs. 22, 23, 24 (not shown). The radiant unit comprising the primary radiant member and the re-radiating member has a base plate with a central hole 234 shaped as shown in Fig. 16. To secure the radiant unit to a Venturi tube 148 a plate secured to the upper end of the Venturi and having the shape of the hole 234 is passed through the hole 234. The radiant unit is then turned through about 90 degrees so that its base plate moves into the space between the plate on the Venturi and a further plate 206 also secured to the Venturi tube 148. A matte or polished aluminium alloy reflector 176 of paraboloid internal shape encloses the radiant unit and is secured by screws 292 to the plate 206. Four holes are formed in the reflector near its rear end to allow escape of trapped air. A guard made of three concentric wire rings connected by three V wires is fastened over the open front end of the reflector. The Venturi tube 148 is formed of two longitudinal sheet metal halves having flanges which are welded together. The Venturi is assembled to a U-shaped yoke 186 to which are clamped a gas spud 142 and an air shield 260 comprising a conical part 262 and two axially extending curved parts the edges of which are spaced to allow passage of supporting brackets 240 attached to the top of the Venturi. One of the curved shields is apertured. The burner is pivotally mounted on trunnions 118 on arms 310 on a yoke rotatably mounted on the top of a post (not shown) and can be clamped in adjusted position by hand screws 254 extending through arcuate slots in the arms 310. The yoke can also be clamped in adjusted position by a further hand screw extending through a slot in a tubular part of the yoke. Gas is supplied to the burner by a flexible hose from a valve mounted in a box near the top of the post. In a modification, Fig. 26 (not shown), an insulated electrode 414 is mounted in a central aperture in the baffle 418 closing the upper end of the primary radiant member and forms an ignition spark gap with the baffle. The gas supply is controlled by a solenoid valve 442 operated by a system including a flame sensor comprising a fluid-filled bulb 444, connected by a capillary tube to a movable diaphragm adapted to operate a switch 452. When a manual or thermostatic switch is closed an ignition transformer T462 and the solenoid valve 442 are energized. If ignition is effected the flame sensor de-energizes a relay 460 which moves contacts 474 to de-energize the ignition transformer and introduce a resistance 458 into the circuit supplying the solenoid fuel valve. The current therethrough is therefore reduced but is sufficient to hold the valve in open position. If ignition does not occur a heater 468 in series with the relay eventually causes a bimetal strip 456 to open a switch 486 to de-energize the solenoid fuel valve. The burner may be incorporated in a hot air furnace, Fig. 27 (not shown), the radiant unit being detachably secured to and the Venturi tube being welded to the bottom wall of the furnace. The furnace is surrounded by a jacket to which air is supplied by a blower. Combustion air is supplied by a duct and the combustion gases flow into aflue. The Venturi and associated gas spud may be replaced by a conduit supplying premixed gas and air.