GB1242409A - Apparatus for measuring and dispensing liquid - Google Patents

Abstract

1,242,409. Forcing liquids by gaseous pressure. PROTEX INDUSTRIES Inc. Oct.16, 1968, No. 49061/68. Heading F1R. Apparatus for dispensing measured quantities of liquid comprises a transparent cylinder 12 to which liquid is fed under pressure from a tank 50 and from which liquid is dispensed via duct 22 under the force of compressed air introduced above the liquid. In operation, momentary actuation of switch 34 causes a solenoid operated valve 58 to be actuated to permit compressed air from cylinder 40 to open a gas pressure actuated valve 54 and to pressurize liquid in the tank 50 via pipe 60 so that liquid is forced into the cylinder 12. As the liquid level rises in the cylinder, a pulsing device 94 is operated by a float, counterweight and pulley arrangement to transmit pulses to a pulse counter 28 which has been pre-set so that when the required volume of liquid is present in the cylinder 12 an interrupter associated with counter 28 causes de-energizing of the valve 58, and venting of pipe 60, and closing of valve 54. The tank 50 is then replenished by gravity flow of liquid from a supply tank 62. The interrupter actuates a pre-set delay timer 30. When the pre-set delay period is over, a circuit to solenoid operated valve 102 is closed thus causing opening of compressed air actuated liquid outlet valve 112 and supply of compressed air via pipe 106 to force liquid from the cylinder. When float 74 reaches the bottom of the cylinder, the magnetic counterweight 80 actuates reed switch 84 which causes opening of the circuit to valve 102 and actuation of a pre-set purge timer 32. The timer 32 when actuated closes a holding circuit to solenoid-operated valve 118 which opens to permit compressed air to flow via conduits to the outlet pipe 108. A fail-safe arrangement is provided by reed switch 86 which, if actuated by the counterweight 80, opens a holding circuit for the solenoid of valve 58 and stops the filling operation. A switch 36 may be switched from its normal "automatic" position to a "hold" position so as to stop the automatic operation of the apparatus or to a "manual" position. When switch 36 is in the "manual" position the switch 34 must be held in its actuated position so as to keep valve 58 and thus valve 54 open. When the required amount of liquid is present in the cylinder return of switch 36 to the "automatic" position will cause the rest of the cycle of operations to commence. The apparatus of Figs. 2 and 2a includes two liquid tanks (although only one tank 166 is shown) and a selector switch 196 which can be set to a position corresponding to the liquid to be dispensed. Filling of the cylinder 134 to the desired level is similar to that described in relation to Fig. 1. When the interrupter de-energizes the solenoid of valve 168 it simultaneously actuates a pre-set dump, delay timer 200. When the timer times out it closes a holding circuit to solenoid operated valve 220, and valve 220 opens to permit compressed air to flow to the cylinder 134 for dispensing the volume of liquid and to valve 148 to permit liquid flow to pipe 146. As timer 200 actuates valve 220 it simultaneously actuates a pre-set dump hold timer 202. When timer 202 times out a pre-set wash-out timer 204 is actuated. The timer 204 actuates diverter valve 260 to open outlet pipe 144 to waste and closes a circuit which causes solenoid operated valve 270 to open and permit flow of water to the cylinder 134. When wash-out timer 204 times out the wash out valve 270 is closed. When water is almost discharged from the cylinder 134 reed switch 234 will be actuated by magnetic counterweight 230 to actuate a pre-set purge timer 206 and to open a hold circuit for the solenoid of valve 220. The wash out and purge phases may be excluded from the cycle of operations by operation of switch 282.