GB1298875A - System for supplying gaseous material to a flow of liquid - Google Patents

Abstract

1298875 Valves PENNWALT CORP 6 Feb 1970 [2 April 1969] 5801/70 Heading F2V [Also in Divisions B1 and E2] Chlorinating system.-Gas is dosed with a flow of liquid by an injector device (25, Fig. 1, not shown) having a check valve (35) to prevent liquid flooding the gas supply and to shut off the gas supply if liquid flow ceases. As described for chlorinating water there are two pressurized gas cylinders (11, 12) each having a pressurereducing and shut-off valve unit (17), 18 supplying a flow rate control unit 20. When the gas pressure in the system falls below a predetermined level the valve unit associated with the gas cylinder in use shuts off automatically and the other opens. Valve units (17), 18, Fig. 2, have a clamp 120 for attachment to a gas cylinder outlet 15, a pressure reducing and shut-off valve 142 carried in a shaft 143 the end of which abuts the nose of a shut-off diaphragm valve 167, the arrangement being such that when one valve is closed the other must be open, but both may be open at the same time. The valve 167 has a shaft 170 and external pin 178 by which it may be manually opened, and it may be retained in the fully open position by magnetic latch 185, 186. The diaphragm 154 is acted upon on the right side (as depicted) by atmospheric pressure, and on the left side by the sub-atmospheric pressure in the system generated by injector 25. Initially the valves 142 are closed and the diaphragms 154 of the units 17, 18 retained by the magnetic latches but when the diaphragms are exposed to the reduction of pressure generated by the injector one of the latches is overcome. The associated valve 142 is then opened admitting gas to the system, the pressure in which (though still below atmospheric) rises to the working pressure which is insufficient to overcome the latch of the other valve unit. The valves 142, 167 then co-operate to maintain the gas pressure constant. Coloured bands 181a, 181b, 181c seen through a window 183 indicate the condition of the apparatus. The magnetic latch may be replaced by a bi-stable mechanical toggle latch (see Figs. 3 and 4, not shown, and Division E2). Failure of gas supply causes the subatmospheric system pressure to fall below working level overcoming the latch of the other valve unit and restoring the gas supply. If the valve unit be detached from a gas cylinder when both cylinders are exhausted, valve 167 closes and remains closed until pressure from a new cylinder acting on diaphragm 154 through check valve 188 opens it again. To change one cylinder while the other is still discharging, the diaphragm of the associated valve unit is pulled to the right by the pin 178 until it is retained by the magnetic latch, whereby valve 142 is allowed to close. The control unit, Figs. 7 and 8 (see also Figs. 5, 6 and 9, not shown) has an inlet passage 50 connected to both gas sources, an externally visible taper tube gas flowmeter 55, and an externally adjustable flow control comprising a metering orifice 54 co-operating with a V- notch plug 61. Thence gas passes through port 66, chamber 67 and valve port 71 to the injector supply conduit. The left side (as depicted) of diaphragm 75 is open to the gas inlet through passages 79, 82 so that it is acted upon by the pressure difference across the orifice 54 and operates to maintain it constant. The control unit also includes a pressure relief valve 81 comprising a diaphragm 88 open on its left side to atmosphere and on its right side to the (subatmospheric) gas inlet pressure. Normally the valve 81 is thus closed but excessive gas pressure opens it to vent the gas through port 90. Insufficient gas pressure causes the diaphragm to move to the right taking with it shaft 91 which operates an externally visible indicator 102.