Patent GB-904714-A (GB)
Title: Improvements in and relating to pipe lines
Inventor: HARTLEY ARTHUR CLIFFORD
IPC: F16L1/16
Filed: 1959-06-26
Abstract: 904,714. Making pipes. HARTLEY PATENTS Ltd., CLIFFORD. June 21, 1960 [June 26, 1959; Oct. 8, 1959], Nos. 21995/59 and 34127/59. Class 83 (2). [Also in Groups XXI and XXVIII] In a method of producing a continuous pipe line a previously formed length of pipe line is supported in a manner allowing axial movement and comprises an outer sheet metal tube 11, an inner sheet metal tube 10 disposed coaxially within it, spacer members 12 in the annular space between the tubes and monolithic concrete 13 filling the remainder of the annular space, the concrete within the rear end portion at least of the length of pipe line being unset. The rear ends of the tubes 10, 11 are secured to the front ends of additional lengths of metal tube which are held in coaxial relation by spacers disposed in the annular space between them, fluid concrete is fed through a plurality of delivery passages 18 extending forwardly through the annular space between the additional lengths to points adjacent the unset concrete in the previously formed length of pipe line, the fluid concrete being delivered into the annular space under a pressure sufficient to fill that space progressively along its length with dense, void-free, monolithic concrete unitary with the unset concrete and to cause relative axial movement between the pipe line and the passages 18 as the space is progressively filled. Concrete is prepared in a concrete batcher and fed through tubes 18 to the forming and welding location shown in Fig. 4. The end section of the outer tube 11 is clamped between the two halves 20a, 20b, Fig. 6, of the cradles 20 and one end thereof is welded at 23 to the pipeline. The end sections of the pipes 10, 11 are staggered to ease the welding together of the lengths of piping. Back pressure due to the infeeding concrete tends to move the structure forward along rails 21 so that the complete pipeline is pushed on to rollers 22, reaction plates 24 being provided near the ends of the feed pipes to increase this tendency. The outer tube is fabricated from steel sheet which is formed and clamped in cylindrical shape in the cradles 20 and welded along the longitudinal joint. The spacer bars may be attached before or after the shell is formed, e.g. by tack-welding. The inner tube is also fabricated from steel sheet which is initially overlapped in order that the tube may be inserted between the ends of the spacer bars, against which it is allowed to expand when in position and its longitudinal joint welded. Each cradle is mounted through jacks 26 on a pair of bogies running on rails 21. Each cradle on reaching first roller 22 is returned to the beginning for re-use. Alternatively, the inner tube may be formed and welded first and the spacer bars attached thereto. Thereafter, the outer tube is formed over the spacer bars and held in the cradle 20 while it is welded. Pre-cast arcuate concrete blocks may be used instead of spacer bars. The blocks are provided at each end with a semi-cylindrical recess so that bores are created in the blocks for the feed pipes 18. Alternatively, concrete blocks or plates which are arcuately curved but have their end edge inclined to the axis of curvature so that a helically-coiled strip is formed by the assembly may be used. The abutting and/or longitudinally edges may be shaped to interlock. The outer tube is preferably protected from corrosion by an external covering, e.g. bitumen rubber.