Method and apparatus for installation and repair of insulated line pipes

A method for installation and repair of insulated piping, wherein the insulated piping comprises an outer pipe made of a weldable polymer material that encases an inner pipe embedded in an insulating layer, and wherein the inner pipe has been substantially exposed over a section between ends of the two outer pipes, the method comprising:

• placing a sleeve coupling, made of a weldable polymer material incorporating a slit that runs lengthwise along the piping, and whose length exceeds the distance between the outer pipes' ends, over the exposed section of the inner pipe so as to overlap the ends of the outer pipes;
• and
• welding the sleeve coupling to the outer pipe at the ends of the outer pipes, by placing an electrically conductive band between the outer pipe and the sleeve coupling, ensuring that free ends of the band project upward through the slit,
• wherein electric current is connected to the band at the ends brought up through the slit, for a determined period of time, to heat the band and the surrounding polymer material so that they fuse together around the band in order to form a weld joint, and
• wherein two series-connected power converters that are connected to two different power sources of different phases are employed, the output voltage is summed via the synchronous operation of two quasi-resonant converters in order to produce the electric current that is to be connected to the band.

An apparatus for installation and repair of insulated piping, wherein the insulated piping comprises an outer pipe made of a weldable polymer material that encases an inner pipe embedded in an insulating layer, wherein the inner pipe has been essentially exposed over a section between two of the outer pipes' ends, wherein a sleeve coupling, made of a weldable polymer material incorporating a slit that runs lengthwise along the piping, and whose length exceeds the distance between the outer pipes' ends, is placed over the exposed section of the inner pipe, and wherein an electrically conductive band is placed between the outer pipe and the sleeve coupling, and whose free ends project upward through the slit, the apparatus comprising:

• a clamping device that comprises a flexible clamping band that is arranged in a loop around the sleeve coupling;
• a tensioning device to which the clamping band's free ends are connected when the tensioning device is to tighten and retain the clamping-band loop for pressing the sleeve coupling against the outer pipe, the tensioning device comprising a supporting component that makes contact with the sleeve coupling, an electrode element, and two contact rollers that are arranged parallel to one another nearby the supporting component with a distance between one another that is substantially smaller than the sleeve coupling's outside diameter, and wherein the clamping band runs between the contact rollers from the loop;
• and
• a power converter which has a quasi-resonant converter for producing the electric current that is to be connected to the band at the ends brought up through the slit, for a determined period of time, to heat the band and the surrounding polymer material so that they fuse together around the band in order to form a weld joint, the quasi-resonant converter comprising a half bridge, a transformer, a choke coil directly connected between the half bridge and the transformer and a pair of an FET driver and an oscillator which is directly connected to the half bridge.

An apparatus for installation and repair of insulated piping, wherein the insulated piping comprises an outer pipe made of a weldable polymer material that encases an inner pipe embedded in an insulating layer, wherein the inner pipe has been essentially exposed over a section between two of the outer pipes' ends, wherein a sleeve coupling, made of a weldable polymer material incorporating a slit that runs lengthwise along the piping, and whose length exceeds the distance between the outer pipes' ends, is placed over the exposed section of the inner pipe, and wherein an electrically conductive band that is pervious to molten plastic is placed between the outer pipe and the sleeve coupling, and whose free ends project upward through the slit, wherein the apparatus comprising:

• a clamping device that comprises a flexible clamping band that is arranged in a loop around the sleeve coupling;
• a tensioning device to which the clamping band's free ends are connected when the tensioning device is to tighten and retain the clamping-band loop for pressing the sleeve coupling against the outer pipe, the tensioning device comprising a supporting component that makes contact with the sleeve coupling, an electrode element, and two contact rollers that are placed parallel to one another nearby the supporting component with a distance between one another that is substantially smaller than the sleeve coupling's outside diameter, and wherein the clamping device runs between the contact rollers from the loop;
• and
• two series-connected power converters that are connected to two different power sources of different phases and two quasi-resonant converters that, via synchronous operation, sum the output voltage by performing a summation function to produce the electric current that is to be connected to the band at the ends brought up through the slit, for a determined period of time, to heat the band and the surrounding polymer material so that they fuse together around the band in order to form a weld joint.