GB1238437A - - Google Patents

Abstract

1,238,437. Fluid-pressure servomotor systems. KNORR-BREMSE G.m.b.H. April 24, 1970 [April 26, 1969; Feb.13, 1970], No.19938/70. Heading G3P. An apparatus for controlling the filling of a container 1 with liquid comprises a piston 4 which raises an empty container to a filling station (not shown), the container thereby closing a switch 12. Fluid from a main duct 17 passes to the fluidic devices 5, 6, 7, 8, 9, 10 via a throttle 19, that of the device 10 causing a pulse at the control input 21 when the switch 12 is closed. The device 8 switches from stable to astable condition and the collapse of pressure in line 24 causes the device 7 to assume its stable state until such a time that the pulse from the delay line 26 arrives at the control input 27. The pulse in the line 28 causes an output at 31 of the bi-stable device 5 which passes through a detector tube 2 into the open air. Also, the absence of an output at 32 of the device 5 puts the device 6 in its stable state in which an output in line 36 is fed to an amplifier 18. Fluid from the main duct 17 then passes to the cylinder 3 to lower the container whilst the latter is being filled at a rate corresponding to the lowering of the piston 4. At the end of the travel of the piston the filling liquid blocks the tube 2. A pulse is thus fed back via a line 43 to a control input of the device 5 switching the latter to its other stable state. An output at 32 switches the device 6 to its unstable state and supply of fluid to the cylinder 3 is cut off. A similar arrangement is disclosed in Fig. 2 (not shown). If a disturbance occurs during the filling operation or during the changing of containers 1, the switch lever 14 is depressed by; means not shown which causes a pulse to be applied to the control input 42<SP>1</SP> of the device 5 so stopping fluid passing to the cylinder 3.