Patent GB-632910-A (GB)
Title: Improvements in and relating to dough depositing machines
IPC: A21C11/16
Filed: 1947-12-24
Abstract: 632,910. Extruding dough on to a conveyer belt or into pans. BAKER PERKINS, Ltd. Dec. 24, 1947, No. 34254. Convention date, Dec. 24, 1946. [Class 87 (ii)] A dough depositing machine comprises an extrusion or depositing chamber having a discharge opening or openings, means (such as a reciprocating knife) for opening and closing the discharge opening(s), a dough reservoir, a valve for controlling communication between the reservoir and extrusion chamber, another valve that admits air under pressure to the chamber to discharge dough therefrom and vents air from the chamber, and means for controlling the positions of both valves in such a manner that air is vented from the extrusion chamber when the first valve is opened to allow dough to pass from the reservoir to the chamber, this controlling means being itself controlled by the level of the dough in the chamber. The figure shows a machine comprising a dough reservoir 92, an extrusion or depositing chamber 50, and a valve 110 vertically raisable from the open position shown to a closed position by means of a pneumatic piston and cylinder 120. At the bottom of the extrusion chamber are one or more openings 76 which can be closed by a knife 130 sliding there across, the knife being operated by a pneumatic piston and cylinder 132. Air under pressure passes from a tank 152 intermittently through a valve 172 and pipe 170 into the extrusion chamber to force dough through the opening(s) 76. When the knife 130 is in the open position the valve 172 connects the tank 152 and chamber 50; when the knife is in the closed position the chamber is connected to atmosphere through valve 172. The valve 172 is solenoid-operated. The supply of air to the ends of the cylinder 120 is controlled by two solenoid-operated valves 244, 246. The supply of air to the lower end of the cylinder 132 is controlled by a solenoid-operated valve 248, and the supply to the upper end by a camoperated valve disposed within a casing 204. The valves 172, 244, 246 and 248 are controlled by electrodes 64, 66, which are disposed in an electric circuit that includes the dough in the extrusion chamber and the three valves. The machine operates continuously and in cycles. At the start of an extruding operation the valve 110 is in the raised (closed) position and the dough m the extrusion chamber is in contact with the end of the upper electrode 64. In these circumstances compressed air passes from tank 152 through valve 172 and pipe 170 into the extrusion chamber, forcing dough out through the openings 76, and the knife 130 reciprocates to cut off the extruded dough into pieces that fall into baking pans. When the level of the dough has fallen so far that it is below the end of the lower electrode 66 an electric circuit is broken and (a) the knife 130 stops in the closed position, (b) chamber 50 is accordingly connected to atmosphere, (c) valve 110 drops and (d) dough passes from reservoir 92 into the extrusion chamber ; the valve 110 can be opened only when the knife is in the closed position. When the level of the dough reaches the end of electrode 64, valve 110 rises and the intermittent action of valve 172 and reciprocation of knife 130 are resumed. The compressed air is supplied to the cylinders 120, 132 from tank 150 and is at a higher pressure than that supplied to the extrusion chamber from tank 152, the tank 152 being fed from tank 150 through a pressure-reducing valve 160. When it is desired to eject all the dough from the extrusion chamber, the result of laying bare the lower electrode may be nullified by closing a manually-operated switch. The electric circuit is described in detail. The knife is pressed against the openings 76 by a spring 146. The extrusion chamber is in two parts 152, 154, which may be separated, for cleaning, by undoing bolts 62. The chamber is connected to the reservoir 92 by nuts 106 disposed in slots 104 which allow swivelling of the chamber to facilitate cleaning. In modifications, (a) the electrodes are replaced by floats carrying mercury switches, and (b) the compressed air inlet is separate from the vent outlet.