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  1. 1. * GB784713 (A) Description: GB784713 (A) ? 1957-10-16 Improvements in fire-alarms for combustible material Description of GB784713 (A) PATENT SPECIFICATION Go Date of filing Complete Specification July 12, 1955. Application Date July 14, 1954. Complete Specification Published Oct 16, 19570 Index at Acceptance:-Class 118 ( 1), D( 1: 4). International Classification: -GO 8 d. COMPLETE SPECIFICATION Improvements in Fire-Alarmn for Combustible Material We, THE BRITISH CECA COMPANY LIMITED, a British Joint Stock Company, and JOHN RONALD FOXCROFT, a British subject, both of 175, Piccadilly, London, W l, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to fire-alarm apparatus for detecting incipient combustion in a stack or layer of granulated combustible material exposed to air or other gas containing oxygen The combustible material may be, for example) ian adsorbent carbon, Catering charcoal or granulated carbon having a catalyst deposited thereon. Combustion detectors or fire-alarms for this purpose generally comprise a number of ternperature-sensitive elements or tappings distributed in the combustible material, for ex ample electrical elements of resistance varying with the temperature; these detectors generally involve delicate and expensive apparatus. Fire-alarm systems are also known comprising one or more pipe lines containing fluid which is maintained at a pressure different from that of the atmosphere by a pump, each of said pipe lines being fitted with one or more fusible plugs by which the pipe is vented to the atmosphere automatically when the temperature rises above a preset limit, the said pipe or pipes being connected to one or more pressure actuated devices by which an alarm is given when a change of pressure
  2. 2. occurs in the pipe line owing to the opening of one or more of the fusible plugs. The present invention consists essentially of an alarm comprising at least one continuous detector tube, made of fusible or thermally plastic material, to be arranged in the combustible material, means for connecting one end of the tube to a source of fluid pressure, and means for connecting the other end of the tube to a device sensitive to said pressure and adapted to control an alarm signal, normally holding it out of operation, in such a way that melting or softening of the detector tube due lPnu. to rise of temperature of the combustible material will reduce the pressure in the tube 50 and cause the operation of the alarm signal. When spontaneous combustion or ignition occurs in the combustible material, combustion is maintained by the air traversing this material, and an incipient fire is created which 55 is liable to spread gradually through the material When the heat reaches the vicinity of a detector tube, the rise of temperature immediately or very soon causes the melting or softening of the fusible or plastic tube where 60 by the pressure therein is reduced, so that the alarm signal operates. One er more detector tubes may be provided, and the tube or each tube may have the shape of a sinuous line with numerous bends 65 to and fro within the combustible material. The invention is hereinafter described with reference to the accompanying drawing, which illustrates diagrammatically an embodiment comprising two detector tubes a, b, arranged 70 in parallel and both connected at one end by way of a pipe c fitted with a pressure gauge d, safety valve e and reducing valve f, to a single source of gas under pressure at g, and connected at the other end by way of a second 75 pipe k fitted with a pressure gauge i to a single alarm-control device j This device consists of a pressure switch in the form of a bellows normally holding down a counterweighted contact arm k so as to keep open a pair of 80 contacts t in an electric circuit m energized by a mains supply at N and including the winding o of an audible alarm such as a bell p. If it is desired to supervise a stack of combustible material comprising several beds or 85 layers q, as shown, each tube a, b may control two or more beds or layers connected in series. Each tube has preferably the shape of a sinuous line with numerous bends to and fro within the combustible material, as shown, the 90 parts of the tube being sufficiently close together for melting or softening to occur at some point thereof after a fairly short time of heating. A system of valves r may be provided for 90 isolating the several
  3. 3. tubes; when the alarm 704,713 No 20561/54. 784,713 signal is operated, due to melting of a tube a or b at any point and resulting closure of the contacts 1, it will then be possible by closing the several valves r so as to isolate the tubes a, b in turn, to identify the tube wvhich has melted and thereby to determine the precise situation of the incipient fire For example, if the closing of the two valves r on the right, which isolate the tube a, does not stop the alarm, then the failure must be in the other detector tube b Where each tube controls two beds or layers, as in the embodiment illustrated, a third valve S may be interposed in each tube between the two beds or layers, which will allow a further determination of the particular bed or layer in which the incipient fire is located. In another arrangement, each bed or layer may be provided with a separate detector tube, or again each tube may control a given zone of one and the same layer covering a large area, the several tubes being connected in parallel and fed from the same source of pressure. The alarm may be tested from time to time by means of a test cock t which will allow the fluid pressure to escape from near the control device j The pressure gauges d and i will show at all times whether equal pressure is maintained throughout the apparatus and the latter is in proper condition for operation; any difference between the readings of the two pressure gauges will indicate that leakage is taking place, due for ex ample to a small local failure of a detector tube. The detector tubes a, b may be made of lead or of another metal or an alloy melting at relatively low temperature, or they may be made of plastic material, such as nylon or polyvinyl chloride, which softens sufficiently under relatively low heating to reduce the fluid pressure just as with the melting of the fusible tubes. The gas employed is preferably inert as regards combustion, for example nitrogen, but in some cases the tubes may be connected by way of the pipe c to a compressed air line under constant pressure, where the use of an inert gas is not considered necessary. Where several beds cr layers of combustible 50 material are providerd with separate detector tubes, each bed will have its own alarm control device, each bed being thus self-contained; in addition to controlling the audible alarm, common to all the beds or layers, each control 55 device may cause the lighting of an individual warring lamp to indicate which bed or layer has developed the excessive rise of temperature. * Sitemap * Accessibility
  4. 4. * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p * GB784714 (A) Description: GB784714 (A) ? 1957-10-16 Improvements in or relating to spark gap arrangements Description of GB784714 (A) PATENT SPECIFICATION Inventor: HORACE FREDERICK JONES 784,714 Date of filing Complete Specification Aug 30, 1955. Application Date Aug 6, 1954. Complete Specification Published Oct 16, 1957. No 22947/54. Index at Acceptance:-Classes 22, J( 2: 17: 28); and 39 ( 1), D( 8: 12 86: 38). International Classification: -C 04 b H 01 j. COMPLETE SPECIFICATION Improvements in or relating to Spark Gap Arrangements We, THE GENERAL ELECTRIC COMPANY LIMITED, of Magnet House, I Kingsway, London, W C 2, a British company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to spark gap arrangemenrits for use in electric surge diverters Electric surge diverters take a number of forms and in one known form, a plurality of metal electrodes are spaced apart in a stack, the gaps between the electrodes being defined by spacers of insulating material The usual material used for this purpose is steatite and one object of the present invention is the provision of a spark gap arrangement which shows great advantage over the known arrangements. According to the present invention, a spark gap arrangement for a
  5. 5. surge diverter includes at least a pair of metal electrodes spaced apart or separated by a spacer or member of insulating material of high permittivity compared with steatite. One particularly suitable material is bariumor barium-strontium-titanate with a small addition of zinc titanate and spacers of either of these materials may be made up in the form of flat rings, the rings being disposed in a stack and separating a plurality of circular plate-like brass electrodes. In order that the invention may be clearly understood, one construction of a multi-spark gap arrangement of a surge diverter and in accordance with the invention will now be described by way of example with reference to Figures 1, 2 and 3 of the accompanying drawings in which Figure 1 shows a side view partly in section of the arrangement, Figure 2 shows a side view of a spacer and Figure 3 shows a top plan view of a spacer Figure 4 shows a side view, in section, of a modification having inserts to improve the impulse sparkover ratio of the arrangement. lNce 3 s 6 d l Referring now to Figures 1, 2 and 3, the multi-spark gap arrangement comprises a plurality say, eighteen, circular plate-like brass electrodes 1 ail of identical form and pressed 50 on one si