GB1409189A - Pneumatic system controlling operation of a filling valve in a container filling machine - Google Patents

Abstract

1409189 Pneumatic control system for filling machines HORIX MFG CO 31 Oct 1973 [27 Oct 1972] 50631/73 Heading B8T [Also in Division F1] A pneumatic pressure system for controlling the operation of means for opening a filling valve of a container filling machine comprises two fluidic control devices 45, 59, both being supplied, from an air source 37, with two identical air streams through opposite nozzles 49, 50 in the control device 45 for example, which direct the streams such that they will impinge each other in an output chamber 47, which is connected to a control chamber 46 by an orifice 48, so producing a pressure build up and hence a flow of air through outlet tube 56. If the stream in control chamber is deflected by an air jet at right-angles to the stream, impingement is prevented in the output chamber and the air escapes to atmosphere through a vent tube 55. The second control device 59 operates in similar fashion. When a container rises up to the filling position a by-pass 39 of air conducting element 35 opens resulting in the air from the air source 37 being vented to atmosphere and a by-pass 87 of another conducting element 83 closes enabling connection between the air source 37 and a pipe 84 to be made. This occurs when an actuating member 81 of a normally closed blow-down valve 80 is operated the valve is momentarily opened, allowing a jet of air to blow down pipe 84 to a junction chamber 72 and hence into a level sensing tube (not shown). This removes any liquid from the sensing tube. Immediately after the blow down a start valve 68 is momentarily opened, by a cam on the machine, causing a jet of air down tube 67 to deflect the impinging streams of air in the second control device 59. The deflected air is vented to atmosphere through an outlet 63 so cutting off the flow of air from the output chamber 64 along a tube 65. Thus there are no deflecting jets entering the control chamber 46 of the first control device 45 allowing the impingement of the converging air streams in the output chamber 47. This produces a flow of air down a pipe 56 to a pneumatic relay 66 which operates the means by which the filling valve (not shown) of the machine if opened. Air also flows through tubes 56, 57 to the second control device 59 where it serves to maintain the deflecting air stream initially provided by the start valve 68; air is also supplied through a tube 71 to the level sensing device via the junction chamber 72. The container is now filled until the liquid level reaches the sensing tube when air pressure builds up in the chamber 72 resulting in an air flow in a tube 76 which deflects the impinging streams in the first control device 45. Thus the air escapes to atmosphere through a tube 55 and the air flow in tube 56 stops resulting in the pneumatic relay 66 operating to close the filling valve and to cut off the supply of deflecting air to the second control device 59, with the result that the deflecting stream is maintained in the first control device 45 through a tube 65. As the container is lowered from the filling position the by-pass of the air conducting element 35 closes while that of the other element 83 opens, thus providing a further deflecting stream to the first control device 45 and preventing blow down until another container is in the filling position. In a second embodiment a variable restrictor 91, a tube 71 and a check valve 89 are substituted by a fixed restrictor and a third fluidic control device.