Patent GB-975115-A (GB)
Title: Improvements in or relating to flame safety lamps
Inventor: BISHOP WILLIAM NORMAN
IPC: F23Q3/00
Filed: 1961-12-23
Abstract: 975,115. Flame safety lamps. WOLF SAFETY LAMP CO. WM. MAURICE Ltd. March 19, 1963 [March 23, 1961], No. 46136/61. Heading F4F. [Also in Division H2] A spark-ignited flame safety lamp comprises a conducting wick tube or a conducting gas nozzle and a circular electrode which may have internal nibs thereon concentric with but spaced from the upper end of the wick tube or the mouth of the gas nozzle. In the embodiment shown in Fig. 1, a conducting wick tube 11 projects upwardly from a fuel container 1 and an outer conducting tube 9 carries a screwed cap 13 which has a circular internal top flange 14 spaced from the upper end of the wick tube so as to form a spark-gap, energized by a magneto or piezo-electric spark generator. The wick tube 11 is electrically connected to the container 1 and the outer conducting tube 9 to a terminal knob 28 insulated from the container 1. The outer conducting tube 9 has an external bottom flange 15 riveted to a hard fibre cover 2 of the container 1, and to a connector 16 fitting into a bored socket 29 bearing a nut forming the knob 28. The wick tube 11 is surrounded by a conducting burner tube 12 surrounded by an insulating tube 10 fitting inside the outer conducting tube 9. The burner tube is axially movable by means of a bored lug therein which receives a rotatable threaded spindle having a knob 22. The cover 2 is removably secured to the container 1 by a lamp glass 3 supported by rods 5 on a ring 6 screwed on to a ring 8 on the container and looked by a magnetic lock 7. In another embodiment, Fig. 2 (not shown), the outer conducting tube 9 and the insulating tube 10 are omitted, and the burner tube is located inside a guide tube secured to the cover 2. The connector 16 is riveted to the base of a conducting pillar on which is mounted a conducting ring concentric with and spaced from the upper end of the wick tube 11. In a further embodiment, Fig. 3 (not shown), a metal top to the fuel container has a flange which is soldered to the container. The guide tube is soldered to the container top and the outer conducting tube is soldered to an annular plate having an upstanding rim. The annular plate overlies an insulating plate with an upstanding rim, the rim of the annular plate providing one contact for the external igniter. In yet another embodiment, Fig. 4 (not shown), the outer and insulating tubes of Fig. 3 are replaced by a sheet metal truncated cone. The circular electrode is formed by the smaller upper end of the cone which has a continuous internal flange. The larger lower end of the cone is soldered to the inner edge of an annular plate having an upstanding rim, the plate and the rim overlying a rimmed insulating plate as in Fig. 3. In yet a further embodiment, Figs. 5, 6 (not shown), the lamp is fueled by compressed butane or propane, and ignition is by a handoperated piezo-electric spark generator contained in a housing within the lamp. A conducting pillar extends from the spark generator and terminates in a ring concentric with but spaced from the mouth of the gas nozzle, the nozzle forming one electrode of the spark gap. The needle of a needle valve controlling gas flow to the nozzle, is adjusted by rotation of the nozzle having a gear profile on it engaging a gear on a shaft disposed on the opposite side of the nozzle from the conducting pillar and turnable by a knob below the lamp container. The spark generator is disposed in a block of insulating material and comprises two cylindrical piezo-electric crystals separated by a disc conductor in contact with the lower end of the conducting pillar, and conducting pressure pads disposed at the outer ends of the two crystals. Pads of electrically-conducting rubber are interposed at both ends of each crystal. A cam bears on one end of a lever, and the other end of the lever bears on one end of the piezocrystal assembly. Rotation of the cam by means of a hand-crank applies pressure along the axis of the assembly.