Patent ID: 7735709

Claim:
An apparatus for joining pipe sections together which are arranged in a generally upright position, a lower end ( 106 ) of an upper pipe section ( 102 ) being lined up with an upper end ( 108 ) of a lower pipe section ( 104 ), the upper end and the lower end forming a welding area ( 115 ), the apparatus comprising: at least two welding equipment carriers ( 148 , 152 ) each supported by at least one conveying device adapted to roll or glide ( 142 ); at least two welding heads ( 110 , 112 ), each welding head ( 110 , 112 ) comprising a cart and at least one welding torch which is supported by the cart, where each welding head is connected to a respective one of the welding equipment carriers ( 148 , 152 ) only by at least one umbilical ( 130 , 132 ); a circular, substantially circular, or substantially oval-shaped welding head guide assembly ( 113 ) having a central opening, which is adapted to be fixed to one of said upper or lower pipe sections, the welding head guide assembly being constructed to support the carts for guiding each welding head ( 110 , 112 ) along said welding area ( 115 ); a stationary guiding device ( 133 ) having at least one circular, substantially circular, or substantially oval-shaped rail or track ( 135 , 136 ) for guiding the at least one conveying device of said at least two welding equipment carriers ( 148 , 152 ) around said welding area ( 115 ); wherein the at least two welding equipment carriers ( 148 , 152 ) are movable independently from each other along the at least one circular, substantially circular, or substantially oval-shaped rail or track.