A tow truck includes a pair of booms comprised of two identical channel-shaped members being secured together in face-to-face relationship to form a space therebetween. Each of the members includes serrations in the side walls in a common transverse plane at the center of the boom and the serrations are closed by weldments. The boom is constructed by taking a blank sheet of rectangular material and shaping it to taper it from the transverse center to the outer ends along all of its edges and providing inwardly shaping V-shaped notches along the transverse centerline. Side walls are then formed by bending and then the resulting two channel-shaped members are placed in edge-to-edge engagement along one end and held in this position by welding while the opposite ends are drawn together such that bending occurs in a plane through the vertexes of the V-shaped notches and the notches are closed. All abutting edges are then welded together to complete the boom.

A pressure vessel for containing fluid at very high pressures is formed from an axially aligned array or stack of like, flexible, relatively thin, dished discs, i.e., Belleville springs. The discs are clamped together axially, so as to flatten them into a pressure vessel wall structure which is pre-stressed in hoop compression along a bore formed by the aligned inner peripheries of the discs, and in hoop tension along the aligned outer peripheries of the discs. Such pre-stress pattern is particularly well adapted to permit the pressure vessel to support very high fluid pressures within the pressure vessel bore. A liner tube may be located within the bore formed by the aligned inner peripheries of the discs, while any suitable end closing mechanisms, e.g., a die assembly and a piston, may be employed to close the axially opposite ends of the pressure vessel bore.

A composite pipeline construction is disclosed wherein a plurality of lengths of steel pipe are connected together, as by welding, to form an elongated tubular shell. One or more layers of a strengthening material, preferably low carbon, martensitic steel strap, are wrapped around the exterior of the shell. Slight clearances or gaps may be provided between the adjacent turns of the wrap of each layer and the wrapping may be done so that the gaps of one layer are covered by the material of the wrap of the next layer. The dimensions and strength of the pipe and wrap are determined so as to satisfy certain design criteria when the pipeline is operating at its normal design pressure. Prior to being placed in operation, the pipeline is subjected to a predetermined prestressing pressure, based upon the aforementioned design criteria, which is sufficient to stress the pipe portions beyond their yield strength but which is insufficient to stress the wrap beyond its yield strength. After depressurization and during subsequent operation at normal pressures, the stresses in the pipe and wrap do not exceed their respective yield strengths.

This invention includes an above ground compressed gas storage vessel of ular or cylindrical configuration. A plug assembly is inserted into the tube and retained therein by a tri-part ring positioned within a groove of larger internal diameter than that of the tube and retained together with said plug. O-rings or a singular packing assembly would be used to seal the plug to the internal diameter of the tube to prevent the escape of gas. A plurality of cylinders are secured in a parallel arrangement using a support structure to increase gas storage capacity while taking up a minimal amount of ground space.

This invention includes an above ground gas storage vessel of tubular or cylindrical configuration. A head or cap with threads mating the threads of the tube is screwed on each end of the tube to form a pressure vessel. Each cap contains a passage therein threaded to mate a reducing bushing. The reducing bushing likewise contains a passage which is at least partially threaded. This passage may be capped to prevent gas flow or valve to allow the flow of gas as required. In an alternative embodiment, the cap assembly is inserted into the tube and retained therein. A packing assembly would be used to seal the tube to prevent the escape of gas. A plurality of vessels are secured in a vertical-parallel arrangement using a support structure to increase gas storage capacity while taking up a minimal amount of ground space.