GB412630A - Improvements in pavement heaters - Google Patents

Abstract

412,630. Road-surface heaters. HAZLEHURST, H. E., 23, Newton Court, Kensington, London. Oct. 5, 1932, No. 27670. [Class 107.] Relates to road - surface heating machines of the kind comprising a horizontal combustion-chamber having at one end a fuel-consuming device, and at the other end an outlet leading to an enlarged hood disposed near the road surface. According to the invention complete combustion is effected within the horizontal main combustionchamber by the turbulent mixing of secondary air with the products of partial combustion, the mixing being effected by means operating partially to obstruct and retard, but not to prevent, the flow of the main body of the combustion gases on their way to the outlet. In the form shown in Fig. 2, air from a fan 6 is supplied through a valve-controlled conduit 5 to an oil burner 1 which is arranged to project fuel into a combustion chamber 2 forming part of an outer main combustion chamber 3. The products of partial combustion are deflected upwardly by an abutment 9 and are thereby mixed with a body of secondary air supplied to chamber 3 by the fan 6. Complete combustion is thereby effected and the gases pass through a vertical conduit 13 to the hood 10, which may be provided with deflectors 11. In a modification, the chamber 2 is formed in the upper part of the chamber 3. In another construction, the combustion chamber 2, Fig. 6, comprises a separate tube 17 mounted within the enlarged end 20 of the chamber 3. A plurality of radially extending fins 18 serve to centralize the combustion-chamber within the casing 3, and provide also a plurality of passages for the secondary air supplied by the fan 6. Abutments 21 and 22 produce the required turbulent mixing of the products of combustion with the secondary air. Further modifications employing an oil burner are also described. In the modification shown in Fig. 12, solid fuel is burnt on a grate 39 to the underside of which air is supplied through a conduit 42 by a fan 6. The products of combustion are deflected upwards through an opening 47 to intermingle with a body of secondary air supplied to the chamber 3 above the upper wall of the combustion-chamber. Some of the secondary air is deflected downwards into the combustionchamber by upstanding abutments 45 disposed near ports or passages 46. The hood, in all cases, may be detachably mounted on the extension 13, and a jib crane is provided on the machine for lifting the hood onto and off a transporting platform. Specification 412,899 is referred to.