GB1326519A - Pipe bend sheaths and the production thereof - Google Patents

Abstract

1326519 Making pipe bend sheaths G MULLENDER 10 Feb 1972 [15 Feb 1971] 6364/72 Heading B3A [Also in Division F2] A pipe bend sheath, for covering thermal insulation for example, comprises a piece of flexible sheet material formed so as to have two stable shapes: a closed shape corresponding to a pipe bend and an open shape in which the longitudinal profile is arcuately corrugated and has the shape of a sector of a hollow body of open-ended hour-glass formation. The sheath is reversably resiliently deformable from one shape to the other. As shown in Figs. 1(a)-1(c) the sheath in the open shape has curved end portions 3, 4 joined by a "saddle" portion 2. The longitudinal edges 1, 5 form the ends of the sheath when the ends 3, 4 are brought together around a pipe bend into the closed shape (Fig. 2(a)-2(c), not shown) and the "saddle" portion 2 springs through to the other side of the peripheries 7, 8 of the enlarged portions 3, 4 to form the inner part of the bend. An extra portion L4 on one curved end 4 produces an overlap in the closed shape on the outside of the bend. As shown in Figs. 3(a)-3(c), a plurality of sheaths may be cut from an embossed sheet which is pressed or moulded from a planar sheet of plastics or metal foil. The embossed sheet has transverse corrugations 30, 32 and longitudinal corrugations 31, 33. Thus, there are produced longitudinal rows of convex hills 34, 37 and concave valleys 35, 36 which have quarter-circle profiles interconnected by straight sections 42, 43 in transverse section. The straight sections 42, 43 correspond to straight end portions L1, L2 of the sheath, Fig. 1(a)- 1(c). The sheet is cut along the dotted lines to produce strips (Fig. 4, not shown) and individual sheaths are produced by cutting the strips across at the appropriate part of the hills 34, 37. Alternatively, the sheaths may be produced from a tube having alternate bulge and neck portions which are quartered longitudinally and cut transversely through the bulged portions.