GB808729A - Improvements in or relating to the transmission of plastic substances for example the feeding of margarine to forming and wrapping machines - Google Patents

Abstract

808,729. Feeding margarine to wrapping machines. UNILEVER Ltd. Oct. 28, 1955 [Oct. 29, 1954], No. 30859/55. Class 87(2). Plastic substances, particularly margarine, are fed from a. supply device to a wrapping machine through a coupling unit which comprises a main conduit 1, a main piston 4 movable therein and having an aperture 5 through which the margarine can pass into the main conduit, conduit means attached to the piston and connecting its aperture to the supply device, a secondary piston 7 attached to the main piston and arranged to be actuated by pneumatic or hydraulic pressure whereby force can be applied to the main piston and thereby pressure to the substance in the main conduit. The conduit means are telescopic and comprise a tube 6 open to the aperture 5, in which is slidable, through packing rings 12, a tube 11 open to the inside of the tube 6 and communicating with the supply device through control means. The tube 6 is also a piston rod connecting the pistons 4 and 7. With the parts disposed as in Fig. 1, margarine enters a conduit 44, passes through a stop-cock 43, through the tube 11 and thence through the tube 6, and through the aperture 5 into a space between a double conical head 15 and the piston 4, the result being that the margarine is distributed evenly over the cross-section of the conduit 1. Margarine continues to be supplied through a crystallizing device 2 and nozzle 3 to the wrapping machine until that machine can deal with no more margarine, whereon the pressure of margarine builds up in the conduit 1 and forces back the piston 4, against the pressure on the piston 7, and thereby compensates for the difference. To deal with larger variations, control means come into operation when the piston 4 reaches either end of its stroke. These control means comprise (i) a valve 42 and (ii) a piston 50 which trips a switch 51. At the extreme right-hand end of the stroke the piston 7 is to the right of an opening 46 in its cylinder 8 and air-pressure, normally transmitted through a pipe 45, ceases to hold up the plunger 52 of the valve 42. The dropping of the plunger 52 blocks the passage between the supply conduit 44 and the tube 11 and opens the conduit 44 to a waste pipe 47 ; thus no more margarine proceeds to the wrapping machine. At the extreme left-hand end of the stroke the piston 7 is on the left of an opening 48 in its cylinder 8 and air pressure is therefore transmitted through a pipe 49 to the piston 50 which stops the wrapping machine. Margarine which may have leaked past the piston may be removed through holes 21 and 22. The modification in Fig. 2 applies compensation on a similar principle, but the telescopic conduit 23, 25 connecting the main piston 26 to the supply device is not within the piston rod which connects the main piston 26 with the secondary piston 34 and, instead of a double conical head, a perforated plate 31 is used to distribute the margarine evenly over the cross-section of the conduit. In Fig. 2 a hot jacket 40 is shown surrounding the crystalizing device 39 ; also homogenising device which comprises two spaced perforated plates 52, 53. It is stated that the pistons can also be actuated by spring or weight loading. Specification 590,935 is referred to.