Provided are a welding device and a welding method that can avoid occurrence of a clearance in a side region of a member and suppress occurrence of a failure of the member due to such a clearance. The embodiment includes: an electrode 11 configured to supply electricity to an electroconductive element 23 arranged between members 21, 22 and configured to generate heat by current conduction; and a pressing element 12 arranged in a side region of one member 22 of the members 21, 22 and configured to press the electroconductive element 23 while elastically being in close contact with the one member 22. Further, the pressing element 12 comes into close contact with the one member 22 by being pushed against the electroconductive element 23 and expanding in a direction orthogonal to a pushing direction.

An integrity monitoring system for a lined pipeline is provided for monitoring the integrity of a polymer liner in a host pipe. Methods and apparatus are described by which a lined pipeline is provided with such an integrity monitoring system sensor cable is able to bridge a joint between sections of lined pipe, for example by routing the sensor cable across the joint via a channel in an electrofusion fitting or by connecting successive lengths of sensor cable via pass-throughs in an electrofusion fitting. Advantageously, the sensor cable is disposed within a continuous annulus between linings and host pipes, and the continuous annulus is maintained across pipe joints using electrofusion fittings.

An integrity monitoring system for a lined pipeline is provided for monitoring the integrity of a polymer liner in a host pipe. Methods and apparatus are described by which a lined pipeline is provided with such an integrity monitoring system sensor cable is able to bridge a joint between sections of lined pipe, for example by routing the sensor cable across the joint via a channel in an electrofusion fitting or by connecting successive lengths of sensor cable via pass-throughs in an electrofusion fitting. Advantageously, the sensor cable is disposed within a continuous annulus between linings and host pipes, and the continuous annulus is maintained across pipe joints using electrofusion fittings.

A power convertor configured to output power to an electrofusion welding coupler for performing electrofusion welding. The power convertor comprises an array of connected DC to DC power convertor circuits. In use, the array of connected DC to DC power convertor circuits is configured to receive, at a first interface, power at a first voltage level from a battery and output power, at a second interface, at a second voltage level to provide power to electrofusion welding cable means. The DC to DC power convertors are arranged in a buck-boost configuration which can operate in a boost mode in which the first voltage level is less than the second voltage level and in a buck mode in which the first voltage level is greater than the second voltage level.

A power convertor configured to output power to an electrofusion welding coupler for performing electrofusion welding. The power convertor comprises an array of connected DC to DC power convertor circuits. In use, the array of connected DC to DC power convertor circuits is configured to receive, at a first interface, power at a first voltage level from a battery and output power, at a second interface, at a second voltage level to provide power to electrofusion welding cable means. The DC to DC power convertors are arranged in a buck-boost configuration which can operate in a boost mode in which the first voltage level is less than the second voltage level and in a buck mode in which the first voltage level is greater than the second voltage level.

A method of repairing a defect of a thermoplastic component is provided. The thermoplastic component has a thermoplastic material at the defect having a first melting temperature, and the defect has a contact surface (TC contact surface). The method includes a) providing a patch comprising a second thermoplastic material having a second melting temperature that is below the first melting temperature. The patch includes a contact surface (TP contact surface); b) disposing a portion of a heating element between the TC contact surface and the TP contact surface. The heating element is operable to heat up as a result of electrical resistance; c) forcing the TP surface toward the TC surface; and d) inputting energy into the heating element to cause the heating element to heat and maintain the TP surface at or above the second melting temperature to produce bonding between the thermoplastic component and the patch.

A coupling component having a first end and a second end, the fitting having a longitudinal axis between the first end and the second end, the first end of the component including a first tubular portion having a first internal diameter adapted to form a sliding fit with a first pipe section, and a first sealer adapted such that the first end can be sealed in use to the first pipe section; the second end having a second diameter or cross-sectional area which is larger than the first diameter and wherein the second end incorporates a flange, wherein at least part of the face of said flange is in a plane substantially non-perpendicular to, or offset from, the longitudinal axis of the component.

A heat shrink component includes a heat shrink layer and a heating unit in thermal contact with at least a part of the heat shrink layer and heating the heat shrink layer to a heat shrink temperature. The heat shrink component has a first dimension in an expanded state and a second dimension in a shrunk state after heating, the first dimension is larger than the second dimension. The heating unit includes an electrically conductive lead heated by an electrical current flowing through the electrically conductive lead and a heat spreading layer arranged in thermal contact with the electrically conductive lead and distributing a heat generated by the electrically conductive lead.

A heat shrink component includes a heat shrink layer and a heating unit in thermal contact with at least a part of the heat shrink layer and heating the heat shrink layer to a heat shrink temperature. The heat shrink component has a first dimension in an expanded state and a second dimension in a shrunk state after heating, the first dimension is larger than the second dimension. The heating unit includes an electrically conductive lead heated by an electrical current flowing through the electrically conductive lead and a heat spreading layer arranged in thermal contact with the electrically conductive lead and distributing a heat generated by the electrically conductive lead.

A liner bridge for a lined pipeline has bores extending through a tubular wall and terminals fitted in the bores, each terminal being exposed to an inward side of the wall for conducting electricity to an electrofusion element. A sealing interface between each terminal and its surrounding bore has one or more projecting formations of the terminal and at least one complementary formation of the bore engaged with the or each of the projecting formations. The interface can also include a sealing mass in the bore.