Patent GB-823702-A (GB)
Title: Apparatus for the control and/or protection of a conveying or hauling device
IPC: F16K31/128
Filed: 1956-02-07
Abstract: 823,702. Fire-extinguishing. MASCHINENFABRIK. PLEIGER. Feb. 7, 1956 [Feb. 19, 1955; March 9, 1955; March 11, 1955; March 12, 1955; May 9, 1955], No. 3808/56. Class 47 [Also in Groups XXIX and XXX] In conveying or haulage apparatus having an hydraulic or pneumatic driving motor supplied with hydraulic or pneumatic power medium via a first pipe-line, control apparatus is provided for switching off the driving motor in response to a reduction in pressure in a second pipeline for hydraulic or pneumatic medium, the control apparatus comprising a first control member for preventing flow of hydraulic or pneumatic power medium in the first pipe line, a second control member having means responsive to the pressure of hydraulic or pneumatic medium in the second pipe line, one or more release members for releasing the hydraulic or pneumatic medium in the second pipeline and to reduce the pressure in the latter and so operate the second control member, and means whereby operation of the second control member is caused to actuate the first control member to cut off the supply of power medium to the motor. In one embodiment, Fig. 7, air is supplied through a pipe 22 via a control valve 20 incorporating a pressure-sensitive member to a belt conveyer driving motor 21, whilst fire extinguishing medium is supplied through a pipe 16 via a non-return valve 23 to a thermally-responsive release element 18 of a sprinkler associated with the belt conveyer. A non-return valve 25 communicates with the pipe between the non- return valve 23 and the release member and also with the pressure-sensitive member of valve 20. When the release member is operated by excessive heat to release the extinguishing medium the pressure reduction is communicated via the non-return valve 25 to the valve 20, operating the latter to stop motor 21. A reserve container 24 of extinguishing medium is provided in case the supply of extinguishing medium through pipe 16 fails. The reserve container, in conjunction with valve 23, generates a pressure sufficient to prevent operation of valve 20 should the supply of extinguishing medium fail when no release member 18 has been operated. In another embodiment, Fig. 8, a flow-responsive valve 27 is provided whereby the flow of extinguishing medium to the release member 18 causes extinguishing medium to flow through a pipe 28 to a further sprinkler. In a further modification, Fig. 14, the release member for extinguishing medium comprises a poppetvalve 74 operated by a diaphragm 71 when overheating of a conveyer belt driving drum 15a causes air trapped within it to expand. Valves 76 and 77 equivalent to the valves 20 and 27 of Fig. 8 are also provided, the former stopping the motor while the latter supplies the extinguishing medium to a pair of sprinklers 75 disposed between the belt runs where the belt passes between the drum 15a and another driving drum 15. Various forms of release member 18 are shown. In one form, Fig. 15, a needle valve 80 is held against its seating by a pair of fusible elements 84. Various modifications of this arrangement are shown. In another form, Fig. 25, a fusible element 84 prevents a spring-urged pivoted plate 102 from acting on a striker pin 105 to open a ball valve 104. The striker pin can also be operated manually. The striker pin may be extended so that when moved it operates a switch to actuate an alarm.