GB1363010A - Method and apparatus for use in sealing a cable against the lengthwise passage of water - Google Patents

Abstract

1363010 Making electrical cables, rolling INTERNATIONAL STANDARD ELECTRIC CORP 19 Oct 1972 [27 Oct 1971] 48138/72 Headings B3A and B3M [Also in Division H1] A method of sealing a space between a cable core 1 and a moisture barrier formed therearound against the lengthwise passage of water, the cable having plastics insulated conductors and the interstices in the core or the interstices and the space being filled with, e.g. petroleum jelly, the moisture barrier comprising a plastics coated metal tape formed into a tube with its edges overlapping and welded together, the method including producing two sets of grooves simultaneously on the surface of the tube, the sets of grooves being oriented so as to intersect one another. The cable core may additionally be provided with a core wrap comprising paper, plastics coated paper or plastics tape or sheet. The core and tube, which is of plastics coated aluminium, are passed through a grooving tool comprising two holders 3 each provided with a plurality of balls 4. The balls are mounted in supporting sleeves or holders (13), Fig. 3 (not shown), which are radially adjustable by screws 5 or (17). The holders are rotated synchronously but in opposite directions, generally at the same speed, but the speeds may differ or one may be stationary. When the space is not filled with petroleum jelly the core is wrapped and the grooving operation welds the tube to the core wrap. When an unwrapped core is used, the jelly fills the space and the jelly filled space is reduced in volume by the grooving operation so that cavities resulting from shrinkage of the jelly disappear. The grooving tool is located between the tool for shaping the tube and an extruder for applying an outer plastics sheath.