A method keeps a voltage or a current constant during a welding process of an electrofusion fitting. The method includes: connecting an extension cable between a connection cable of a welding power supply and the electrofusion fitting to be welded; detecting the extension cable by the welding power supply; detecting and recording the electrofusion fitting to be welded and its data by the welding power supply; autonomously supplying the current or the voltage with the welding power supply; and autonomously regulating the current or the voltage based upon the detection of the connected extension cable and a resulting resistance due to the connected extension cable. The current or the voltage is adjusted such that the current or the voltage remains constant during the welding of the electrofusion fitting.

Disclosed is a method of resistance welding between composite articles. A conductive element is provided between faying surfaces, having a plurality of lower resistivity electrode portions spaced apart along the length of the contact area between the composite articles. The electrode portions can be used to spot weld across the electrode portions, and along a longitudinal portion of the conductive element between the electrode portions by application of an electrical current. Also disclosed are apparatus for use in the resistance welding methods and composite articles and structures and elements incorporating the conductive element.

A method of joining a non-metallic pipe to a metallic pipe. The pipe may be wrapped with one or more sheets of reinforcement material (e.g., pre-impregnated fiberglass, carbon fiber, or aramid fiber) and then fitted with an adapter or fitting that is connectable to a metallic pipe. The reinforcement material may be heated using a heating apparatus which allows the material to bond to the pipe to strengthen the joint.

A system for coupling pipes includes a first pipe having a tapered, spigot end; a second pipe having a tapered, spigot end; and a coupler having two tapered socket ends adapted to internally receive the respective tapered, spigot ends of the first pipe and the second pipe. The first pipe and the second pipe are made from a reinforced thermosetting resin (RTR). The coupler comprising a resistive element implanted therein and connected to electrodes extending to an exterior of the coupler. A thermoplastic material is disposed between an exterior of the first pipe and an interior of the coupler. A thermoplastic material is disposed between an exterior of the second pipe and the interior of the coupler. Upon application of electricity to the electrodes, the resistive elements are heated sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler. A method of coupling pipes includes disposing a thermoplastic material between an exterior of a first pipe and an interior of a coupler; disposing a thermoplastic material between an exterior of a second pipe and the interior of the coupler; inserting the first pipe and the second pipe into the coupler; and applying of electricity to electrodes of the coupler such that resistive elements of the coupler heat sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler.

A surface cleaning apparatus uses an inverted cyclone. An air flow path extends from a dirty air inlet to a clean air outlet. A suction motor is positioned in the air flow path. The inverted cyclone is downstream from the dirty air inlet in a first cyclonic cleaning stage. The cyclone defines a cyclone chamber having a lower air inlet, a lower air outlet and an upper dirt outlet. An openable dirt collection chamber is in communication with the upper dirt outlet.

A system for coupling pipes includes a first pipe having a tapered, spigot end; a second pipe having a tapered, spigot end; and a coupler having two tapered socket ends adapted to internally receive the respective tapered, spigot ends of the first pipe and the second pipe. The first pipe and the second pipe are made from a reinforced thermosetting resin (RTR). The coupler comprising a resistive element implanted therein and connected to electrodes extending to an exterior of the coupler. A thermoplastic material is disposed between an exterior of the first pipe and an interior of the coupler. A thermoplastic material is disposed between an exterior of the second pipe and the interior of the coupler. Upon application of electricity to the electrodes, the resistive elements are heated sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler. A method of coupling pipes includes disposing a thermoplastic material between an exterior of a first pipe and an interior of a coupler; disposing a thermoplastic material between an exterior of a second pipe and the interior of the coupler; inserting the first pipe and the second pipe into the coupler; and applying of electricity to electrodes of the coupler such that resistive elements of the coupler heat sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler.

A method of joining segments of non-metallic pipe and an apparatus that may be used to form the joint. The pipes may be joined using by melting the ends to form a butt joint, then the joint may be wrapped with one or more sheets of reinforcement material (e.g., pre-impregnated fiberglass, carbon fiber, or aramid fiber). The reinforcement material may be heated using a heating apparatus which allows the material to bond to the pipes to strengthen the joint.

A device for positioning in the body of an animal, the device comprising a first portion and a second portion that may be positioned in contact with one other, the first portion and the second portion each comprising a biocompatible conductive thermoplastic material, such that when the device is positioned in the body of an animal and electric current flows from the first portion to the second portion, heat is generated by electrical resistance at the point of contact between the first portion and the second portion so as to melt regions of the first portion and the second portion, and when the electric current is thereafter terminated, the melted regions of the first portion and the second portion re-solidify so that a weld is formed between the first portion and the second portion.

A device for positioning in the body of an animal, the device comprising a first portion and a second portion that may be positioned in contact with one other, the first portion and the second portion each comprising a biocompatible conductive thermoplastic material, such that when the device is positioned in the body of an animal and electric current flows from the first portion to the second portion, heat is generated by electrical resistance at the point of contact between the first portion and the second portion so as to melt regions of the first portion and the second portion, and when the electric current is thereafter terminated, the melted regions of the first portion and the second portion re-solidify so that a weld is formed between the first portion and the second portion.

A heating circuit for joining disposed between members includes a heating wire; and a plurality of projections projecting from the heating wire in a facing direction in which the members face each other. Each length of the plurality of projections in the projecting direction is not less than half a layer thickness of a fused layer obtained by the members being melted.