GB1283050A - Apparatus for preventing the over-filling of a receptacle with material fed thereto - Google Patents

Abstract

1283050 Fluid-pressure servomotor systems WESTINGHOUSE BRAKE & SIGNAL CO Ltd 8 Oct 1969 [8 Oct 1968] 47576/68 Heading G3P The over-filling of a receptacle, such as a compartment in a road or sea-going tanker, includes a valve 2, Fig. 1, whereby the flow of material is permitted or prevented by the presence or absence of a first fluid-pressure signal 7, a fluidic circuit 12 for permitting or preventing the presence of the first fluid-pressure signal in dependence on the presence or absence of a second fluid-pressure signal 14, and sensing devices 15 for permitting or preventing the presence of the second fluid-pressure in dependence on the level of the material in the receptacle being below or at a predetermined level. The valve Z is actuated by a piston 5 under the control of a relay valve 9 which is in turn controlled by the fluidic circuit 12 connected by a plug and socket 17 to the liquid sensing devices 15 in the compartments of the tanker. The line 10 applies pressure fluid to the relay valve 9 and to the fluidic circuit 12 through a pressure regulator 13. This fluidic circuit is shown in Fig. 2 and consists of two biased Schmitt triggers with their outputs 28, 38 connected through a passive AND gate 32 to the relay 9. When one of the sensing devices 15 opens a line 14 to atmosphere causing the bias on one trigger to switch the output to a port 27, the AND gate moves the relay 9 to a position in which the valve Z is closed. An indicator 29 is operated whenever the port 27 is pressurized and a second indicator 39 is operated and the valve 2 again closed if an abnormal rise in pressure in the line 14, which may be due to blockage, increases the bias on the other trigger. Each device 15 may be constructed as shown in Fig. 3 in which a valve 52 has inlets and outlets 56, 59 connected to the line 14 and a ball closure 53 is operated by a float 50 also connected with the line 14 through a tube 60. When the ball 53 is lifted, the line 14 is connected to vents 57. The device of Fig. 3 may be replaced by a spring-loaded single beat lift valve operated by a double diaphragm. A further alternative to the device of Fig.3 uses an O-ring seal operated by a double diaphragm to raise the pressure in the line 14 when the compartment has been filled to the required level. The plug and socket 17 provides both a fluid-tight seal and an electrical connection between the parts of the apparatus on the tanker and the parts carried by a gantry at the filling station.