Patent GB-190625258-A (GB)
Title: Improvements in Apparatus for Testing Miners Safety Lamps or the like.
Inventor: HAILWOOD ERNEST ARTHUR
Filed: 1906-11-09
Granted: 1907-06-20
Abstract: 25,258. Hailwood, E. A. Nov. 9. Miners' safety lamps.-Relates to apparatus for testing miners' safety lamps, and comprises a chamber adapted to be filled with an explosive gaseous mixture and to enclose the lamp to be tested, which has been previously lighted, or is provided with an electric igniter so that, if the lamp is defective, the gaseous mixture is exploded by the previously lighted flame or by the electric igniter as soon as this is set in operation. Figs. 1 and 2 show one form of construction. A chamber 2 is secured to a bracket 1. Gas is supplied from the main 4<b> through a cock 4<c> to a Bunsen injector 6 where it mixes with air, thence through tubes 4 to perforated rings 4<x> in the chamber 2. An outlet 3 has a valve 3b, adapted to be closed by a cam 26 against the action of a spring 3<c> and to be retained closed by a spring catch 3<e>, which is released by the engagement of a lug 3<h> with a tappet 3<a>. When an explosion occurs, the pressure within the chamber is relieved by. a spring-pressed valve 3<a> which simultaneously closes the push switch 31 of a relay 57, whereupon a second switch 38 is released and closes, and a bell signal 39 is set and remains set until the relay is restored by hand. A baseplate or frame 7 for carrying the lamp is mounted on a rack 20 operated by a pinion 22, by means of which it can be raised to introduce the lamp into the chamber 2 and to close the opening of the said chamber, with which opening the frame 7 makes a sliding fit. Electric contact switches 8 ... 13,16, and 17<a> are provided in the circuits of the battery 18 and sparking-coil 14. The cock is normally maintained in the closed position by springs 4<d>, and has an arm 4<c> adapted to be operated by a projection 28 on the rack 20. The pinion and tne cam are mounted on a shaft 23 operated by a rope 24 passing over pulleys 25, 24<a>, the latter of which is keyed to the shaft 23. The lamp being placed in the plate 7, the rope 24 is manipulated. While the lamp is moving up into the chamber, the projection 28 deflects the arm 4<c> and opens the cock for a short time, depending upon the length of the projection 28, and the cam closes the outlet 3. When the lamp reaches the top of its course, the electric switches are closed and sparks set up within the lamp. To remove the lamp after the completion of the test, the operation is reversed. The lug 3<h> which had passed the tappet 3<g> now depresses it and releases the spring catch 3<e>, whereupon the outlet valve opens and the enclosed gases are discharged. The arm 4<c> is again deflected by the projection 28, but in the opposite direction, the cock not being opened thereby. To prevent the plate from being lowered too soon, teeth 29 are formed on the projection 28 ; these teeth engage with the arm 4<c> so long as the projection 28 has not cleared the arm 4<c>. The apparatus may take various other forms, and the several parts and details may be modified. The frame 7 may be operated by means of lever mechanism, gearing, or otherwise. The relative motion of the frame 7 and chamber 2 may be obtained by fixing the frame 7 and rotating the chamber around it, suitable openings being provided in each adapted to coincide in one position to allow of the insertion and removal of the lamp ; or the chamber may be adapted to receive the lamp through a door 72, the various operations being performed by the closing of the door, as shown on the right of Fig. 11, or by a combined locking-bolt and valve 71 and a spring push 80, as shown on the left of Fig. 11. Several lamps may be mounted on a common frame, in which case the switches of the several lamps are arranged to be closed one at a time in succession. Several chambers and frames may be mounted together and operated simultaneously, or in succession. A supplementary door may be provided so that a new lamp can be inserted while the other is being removed. Vanes 40 may be provided in the chamber and adapted to be moved for thoroughly mixing the gases. The gas supply may be arranged to pass to the bottom and top rings 4<x> alternately. The gas may be forced to or sucked into the chamber by means of a pump, in which case the Bunsen injector may be dispensed with and suitable air-inlet valves provided instead. The gas inlet may be controlled by slide, disk, or other valves, which may be actuated by a treadle or otherwise. It may be arranged that the gas continues to flow to or through the chamber even after the lamp frame has reached its innermost position. The outlet valve may be modified. The outlet may be left always open without a valve, in which case no special relief valve need be provided. There may be no other outlet besides the relief valve. The same charge of gases may be retained in the chamber for testing several lamps in succession or the exhaust may be led into an accumulating chamber and used over and over again. The relief valve may be arranged to close an electric switch in a relay circuit for the purpose of closing a gasinlet valve. The various gas passages may be protected by wire-gauze. The various parts may be enclosed in gas-tight cases, which may be locked. In a modification, shown in Fig. 12, a gas valve 63 and an electric push-switch 61 are combined together.