Abstract:
A cross-linkable polymeric casting composition including an effective amount of A: an acrylic or methacrylic monomer which provides high rigidity and low color dispersion (High Abbe number) to the final product; B: a di- or polythiol compound; C: a di- or polyvinyl monomer; and optionally D: a polymerizable comonomer.
Abstract:
An apparatus and method for lining an underground conduit is disclosed. The apparatus 10 comprises: an annular frame 40 having a crown portion 42 and a base portion 49; a strip guide disposed around and supported by the annular frame 40, the guide arranged to guide a strip 12 around a helical path; a pair of strip pinch rollers mounted to the frame 40 at a position circumferentially about halfway between the crown portion 42 and the base portion 49; a drive assembly mounted to the frame for driving the strip 12 downwards into the helical path in a winding direction so as to present an incoming first edge to an adjacent second edge of a wound convolution of the strip; a liquid remover mounted to the frame, the liquid remover arranged to prevent liquid that has adhered to and ascended with the second edge from descending down towards the incoming first edge; and an extruder 80 mounted to the frame 40 for extruding a molten bead of plastic onto the strip 12 at a position just before said overlap.
Abstract:
An hydraulic control arrangement (66) in association with a pipe relining machine Includes fluid pressure supply and return lines (32, 33), a motor controller (80) to control a motor (67) and a radial position controller. The radial position controller supplies fluid under pressure to a radial positioning arrangement (46) to set diameter of a relined pipe. The radial position controller has a first normally closed valve (83) supplying fluid under pressure to the radial positioning arrangement (46) and a second normally open valve (84) allowing fluid to be withdrawn from the radial positioning arrangement (46). The arrangement (66) allows the pipe relining machine to be withdrawn in the event of a failure.
Abstract:
A spool winding assembly for winding a composite strip onto a spool having a hub is disclosed. The strip includes an elongate plastic strip having a flat base portion and a plurality of laterally spaced apart lengthwise extending rib portions upstanding from the base portion; and a plurality of elongate reinforcing members extending lengthwise within respective rib portions, the rib portions and the reinforcing members forming composite ribs. The assembly includes: a main frame, a spool holder for rotatably supporting the spool relative to the main frame, a spool drive unit for driving the spool with respect to the main frame, a carriage mounted for lateral movement with respect to the spool, a bender mounted to the carriage for receiving the strip as it is fed towards the hub of the spool and for deforming the strip to give it a curved base portion, and a bender drive unit operably connected to the bender for driving the strip through the bender.
Abstract:
An apparatus and method for lining an underground conduit is disclosed. The apparatus 10 comprises: an annular frame 40 having a crown portion 42 and a base portion 49; a strip guide disposed around and supported by the annular frame 40, the guide arranged to guide a strip 12 around a helical path; a pair of strip pinch rollers mounted to the frame 40 at a position circumferentially about halfway between the crown portion 42 and the base portion 49; a drive assembly mounted to the frame for driving the strip 12 downwards into the helical path in a winding direction so as to present an incoming first edge to an adjacent second edge of a wound convolution of the strip; a liquid remover mounted to the frame, the liquid remover arranged to prevent liquid that has adhered to and ascended with the second edge from descending down towards the incoming first edge; and an extruder 80 mounted to the frame 40 for extruding a molten bead of plastic onto the strip 12 at a position just before said overlap.
Abstract:
A cross-linkable polymeric casting composition including an effective amount ofA: an acrylic or methacrylic monomer which provides high rigidity and low colour dispersion (High Abbe number) to the final product;B: a di- or polythiol compound;C: a di- or polyvinyl monomer; and optionallyD: a polymerisable comonomer.
Abstract:
A cross-linkable polymeric casting composition including an effective amount ofA: an acrylic or methacrylic monomer which provides high rigidity and low colour dispersion (High Abbe number) to the final product;B: a di- or polythio compound;C: a di- or polyvinyl monomer; and optionallyD: a polymerisable comonomer.
Abstract:
A composite strip 10 windable to form a helical pipe is disclosed. The composite strip 10 comprises: an elongate plastic strip 11 having a base portion 12 and at least one lengthwise extending rib portion 20 upstanding from the base portion 12; and an elongate reinforcing strip 30 extending lengthwise and supported laterally by the rib portion 20, the reinforcing strip 30 having a height to thickness ratio of at least three to one and orientated substantially perpendicular to the base portion 12. When wound into a helical pipe, the reinforcing strip 30 reinforces the pipe against radial crushing loads. A bead 40 seals the reinforcing strip 30 from the environment. Desirably the composite strip 10 further comprises: a planar lamina 50 extending lengthwise and bonded to the base portion 12, the lamina 50 having a higher Young's modulus and strength than those of the plastic strip 11. The lamina 50 greatly improves the pressure rating of a pipe wound from the strip 10.
Abstract:
A composite strip 10 windable to form a helical pipe is disclosed. The composite strip 10 comprises: an elongate plastic strip 11 having a base portion 12 and at least one lengthwise extending rib portion 20 upstanding from the base portion 12; and an elongate reinforcing strip 30 extending lengthwise and supported laterally by the rib portion 20, the reinforcing strip 30 having a height to thickness ratio of at least three to one and orientated substantially perpendicular to the base portion 12. When wound into a helical pipe, the reinforcing strip 30 reinforces the pipe against radial crushing loads. A bead 40 seals the reinforcing strip 30 from the environment. Desirably the composite strip 10 further comprises: a planar lamina 50 extending lengthwise and bonded to the base portion 12, the lamina 50 having a higher Young's modulus and strength than those of the plastic strip 11. The lamina 50 greatly improves the pressure rating of a pipe wound from the strip 10.
Abstract:
A crosslinkable polymeric casting composition comprises an aromatic polyvinyl monomer such as divinyl benzene, a polythiol such as pentaerythritol tetrakis-(3-mercaptopropionate), an epoxide strain-reducing agent such as hexanediol diglycidyl ether, and, optionally, a polymerizable comonomer such as polyethylene glycol dimethacrylate.