GB1343802A - Explosively-operated valve - Google Patents

Abstract

1343802 Dishwashing machines P G WATTERBACK 19 April 1971 [13 Feb 1970 19 Aug 1970] 21602/71 Heading A4F [Also in Division F2] In an explosively operated valve for controlling flow of water to a dishwashing machine, if the flow direction is from 3 to 5 Fig.1, then closure member 9 is normally held on its seat 7 by threaded actuator 11 and flow is allowed by check valve member 21 and ports 49, 51. If the glow plug 47 is energized, e.g. by closure of a switch by a leakage detector below the machine, then percussion cap 45 is detonated and piston 27 is driven downwards to hold the closure member 21 against seat 19. The piston remains in its depressed position due to its tight fit within extension 31 of closure member 9. With the valve mounted for reverse flow, closure member 9 serves as a throttling member and detonation of cap 45 is effective in that case to drive the piston downwards until closure member 9 engages its seat where it is retained due to its tight fit in actuator 11. Gas pressure is vented via passage 55 and paint seal 57, fracture of which indicates operation of the valve. Seal rings 33, 37 can be omitted if piston 27 and member 9 are of Teflon (R.T.M.) Withdrawal of actuator 11 allows replacement of the percussion cap and resetting of piston 27 and member 9. In Fig.2, a closure member 71 of nylon or Teflon (R.T.M.) is driven downwards following detonation of nitrocellulose disc 91 by an electrically fired detonating mixture at 85. The gases are vented at 95. The explosion may alternatively be generated by allowing the mixing together of two substances, such as potassium permanganate and hydrogen peroxide, in response to an applied signal. One of the substances can be contained in a frangible plastics ampule or in a chamber with a frangible wall. A pressure signal may actuate the valve instead of an electrical signal.