GB1300801A - Methods of and apparatus for controlling the advancement of materials - Google Patents

Abstract

1300801 Extruding; drawing WESTERN ELECTRIC CO Inc 27 Jan 1970 [28 Jan 1969 14 Nov 1969] 3860/70 Heading B3P A continuous bar feeding apparatus has one or more fluid flow zones D 1 , D 3 , D 5 , D 7 where the flow is along the surface of the bar R to produce a drag force on the bar to feed it or retard the feed. The fluid flow may be continuous in a forward-reverse pattern or each zone may have a closed fluid-loop with different fluids, Fig. 2 (not shown). The pressure levels of the fluids are controlled by pressure ratio valves (RV) between the zones. The fluids may have different viscosities and treat the bar for cleaning, rinsing, chemical treating and lubricating respectively. One embodiment of feeding apparatus, Fig. 3, for an extrusion die 12 comprises a housing 16 with a set of flow reversal cells 20, 22, 24, 26. The cells each comprise an insert 30, Fig. 4 (not shown), and end plates 36. arranged to provide a forward-reverse flow path. The plates 36 and the end wall of the housing have low-friction inserts (40), 60. For best results it has been found necessary to have the internal diameter of the housing greater than twice the bar diameter. In one example using this apparatus the fluid is polyethylene micropowder and silicone fluid. The lengths of the flow path along the bar may vary from zone to zone, Fig. 7 (not shown). The fluid may be cooled. In a second embodiment, Fig. 8, the bar R is fed to a high pressure extrusion apparatus 200 by a fluid-drag feeder 110 and the extruded product may be controlled by either a fluid-drag feeder 310 to accelerate the feed or a feeder 210 to retard the feed. Alternatively the feeder at the output side may initially retard the extruded wire W and the flow direction is then reversed to accelerate the wire. In some operations the input feeder may be dispensed with and the wire drawn through the die by the output feeder 310. The pumps F/P of the feeders and the extrusion apparatus 200 are controlled by adjustable pressure control valves, Fig. 9 (not shown). The feeders may include electric heating elements 70, Fig. 11, so that the viscosity of the fluid can be varied. The elements of the units are connected in series and the current controlled by an amplifier fed with signals from transducers for the extrusion forces. The apparatus is particularly suited for extruding and drawing brittle metals such as bismuth and beryllium but can be used for aluminium.