A large tubular plastic tank, for use in holding unpressurized water or wastewater, is formed by fusion welding together half-shell parts at lengthwise flange joints to form a tubular body. Then, end caps are fusion welded onto the outermost ends of the tubular body and an assembly of two or more bodies. Fusion weld elements are secured beforehand to the joining surfaces of the tank parts at a factory; the tank parts are then economically stored or shipped in nested condition to a fabrication site remote from the manufacturing site. Electric or electromagnetic energy is used to melt in situ the fusion weld elements which are captured between the joining surfaces of the parts.

A pipe coupling construction which can be used for coupling of a high-pressure pipe includes an inner bush of a non-metallic material and an outer bush, which bushes in axial section have parts which mesh with each other in order to transmit axial forces. The inner bush can be fused or adhered to an outer cover layer of the pipe. The coupling has a metal sleeve construction. The outer bush has an outer bush protruding end which protrudes with respect to the inner bush and the metal sleeve construction is at least partially located within the outer bush protruding end. The metal sleeve construction and outer bush in axial section have parts which mesh with each other.

The invention relates to a method for connecting a thermoplastic line element (3) to a connecting element (2). The method comprises the steps of: providing the at least one thermoplastic line element (3); providing the connecting element (2) having a thermoplastic body (4 wherein a heating element (6 is embedded in the body (4 for generating heat in a welding region (5 for welding the body (4 to the at least one line element; joining the connecting element (2) to the at least one thermoplastic line element (3; providing a welding device (10) for welding the connecting element (2 to the at least one thermoplastic line element (3); welding the connecting element (2 at least one thermoplastic line element (3 by generating heat in the welding region (5 by means of the welding device (10).

The welding of the connecting element (2) to the at least one thermoplastic line element (3) is stopped by the welding device (10) before the end of the planned welding duration if an error criterion is met.

A wind turbine blade 2 comprises a profiled contour including a leading edge 34 and a trailing edge 33 as well as a pressure side and a suction side. The profiled contour is formed by a first shell part 10 and a second shell part 15 being bonded together in a bonding region between the first and the second shell part by a curable bonding means 40. The first and the second shell part 10; 15 are formed in a fiber-reinforced polymer. The wind turbine blade further comprises resistive heating means 50 being arranged in thermal connection with the bonding means 40 such that the resistive heating means 50 supplies heat for curing of the curable bonding means 40 during assembling of the wind turbine blade.

An electrofusion fiting (20) comprises a fitting body (24) and an electrofusion collar (26). The fitting body (24) has an exterior surface (30), an interior surface (32), and a terminal portion (44) extending to a rim (34). The collar (26) has: an inner wall (42) having a heating element (60); a segmented outer wall (40) spaced radially apart from the inner wall; and a linking portion (46) linking the outer wall and inner wall. The fitting body terminal portion is between the inner wall and the outer wall. The collar and fitting body have interfitting features (150, 152) axially retaining the collar against extraction from the fitting body while permitting relative rotation of the collar and the fitting body.

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.

The invention relates to a weldable connecting element 2 for connecting or joining thermo-plastic line elements 3. The connecting element 2 comprises: a thermoplastic body 4; at least one heating element 6, which is embedded in the body 4, wherein the heating element 6 serves to generate heat in a welding area 5 for welding the body 4 to the at least one line element 3. Furthermore, a joining control 12 is provided, which is configured to prohibit the welding operation and/or to interrupt the welding operation if the body 4 and the line element 3 are not joined correctly.

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.