GB1406456A - Twin wire former - Google Patents

Abstract

1406456 Paper-making apparatus BELOIT CORP 31 Aug 1972 [6 Oct 1971] 40448/72 Heading D2A A paper-making machine comprises twin wires 10, 11 extending round breast rolls 12, 13 to form a gap at the nip between the rolls, a headbox 23 having a slice 24 directed towards the gap, and a container 26 holding liquid, e.g. white water, which submerges the nip, whereby a jet of stock leaving the headbox and passing through the liquid in the container 26 to the gap will not entrain air and will be free of surface disturbance. The wires form a tapered throat 14 and then extend past spaced laterallyextending members 16, a suction box 19 and a suction couch roll 20. Doctors 17 are also provided, and the web is carried by the wire 11 to a pick-up roll 22. The velocity of the jet of stock leaving the slice 24 is substantially that of the wires. The wires and headbox may extend horizontally, the wire-web-wire sandwich being thereafter directed round a roll out of the liquid in the container. The jet of stock may not engage the wires until they leave the nip between the rolls 12, 13 to avoid pumping. If the stock delivered to the gap is more than can be taken away by the wires the excess stock flows back into the container 26. The breast rolls may be adjustable to vary the width of the gap for controlling the basis weight of the paper. Devices 29 may be used to reduce the stock jet thickness also for controlling the basis weight of the paper, and the devices may be adjustable differentially throughout their lengths for controlling the basis weight across the web, or the devices may be for delivering additional jets of stock to the jet leaving the slice 24 to increase the stock jet thickness.