Patent GB-782670-A (GB)
Title: Improvements in or relating to flexible ducts, particularly for mine ventilation
IPC: F16L11/22
Filed: 1953-12-28
Abstract: 782,670. Flexible pipes; pipe joints; supporting pipes. SCHAUENBURG, H. G. Dec. 28, 1953 [Feb. 16, 1953; June 18, 1953], No. 35988/53. Addition to 758,350. Classes 99(1) and 99(2). In the duct decsribed in the parent Specification wherein a tubular body of synthetic resin material is prevented from collapsing inwardly by diameter-holding means which comprise axially-spaced wire rings or an extended helical wire coil secured to the outside surface of the duct, the rings or coil are rectangular in crosssection and are embraced and secured by a channel-shaped strip of synthetic resin material welded or stuck to the duct ; the greater dimension of the rectangular section extends transversely to the surface of the duct. As shown in Figs. 2, 3 and 5, the helical wire coil 4 is enclosed in a flanged, channel-section strip 2, duct-suspending rings 8 enclosed in a synthetic resin material being located under the coil. The ends of the duct are doubled-over to enclose steel rings 5, and are protected against wear by profiled sealing strips 7. The abutting ends of adjacent lengths of duct are connected by a split coupling-ring 6 having conical inner surfaces 6f and contracted by a toggle lever 6c, pivoted to an arm 6d provided with a pin 6e engageable with a rack 6b. In modifications, (a) rings 9, Fig. 7, are secured to the outer surface of a shell 5 concentric with the duct 1, there being holes 8 provided in the duct so that fluid from the latter flows into and inflates the shell ; spaced apart rings or a helical coil may surround the duct, (b) the chamber 7 shown in Fig. 7 is subdivided into inflatable, longitudinal compartments by a number of concentrically arranged shells, Fig. 8 (not shown) or by a flexible pipe 11, Fig. 11, having a wall of wave or zig-zag formation alternately secured to the duct and the shell 5, (c) the duct, Fig. 12 (not shown), is provided with apertures at both ends thereof to allow fluid passing into the chamber 7 to flow back into the duct, or the shell 5, Fig. 13 (not shown), is provided with outlet apertures to allow the fluid to be exhausted to atmosphere, (d) the chamber 7, Fig. 14 (not shown), is filled with air or a heat-insulating gas, and the shell 5 is provided with non-return valves for the inflation thereof, (e) the duct is provided with a flexible covering 16, Fig. 15, of foamy, spongy, mossy or other porous or cellular material which is moistened by water distributed thereover from nozzles 19 in a conduit 17, the fluid flowing through the chamber 7 producing an evaporative cooling effect on the fluid in the duct, (f) the duct and the shell, Fig. 16, are each provided with an outer helical coil and interconnected by spacing members 22, the duct being connected to a duct 21 of smaller diameter, and the shells of adjacent ducts having connecting means separate from those of the ducts, and (g) the shell 6, Fig. 18, of each length of duct has a roughened outer surface, e.g. by fabric fibres or cellular materials, which is moistened by liquid distributed thereover and from an apertured conduit 3 ; fluid passes from the duct via apertures 8 back into the duct through apertures 10, or to atmosphere by way of apertures 9 in the shell.