Georg Fischer Aktiengesellschaft

George Fischer Limited

Fritz Reich

Alfred Thalmann

Ernesto Lehmann

Hans-Werner Steinmetz

An adapting piece of thermoplastic material includes at least one welding sleeve portion with an electrical heating device formed by two heating mats arranged next to each other in circumferential direction. The welding sleeve portion has at least one radial incision extending in axial direction. By means of a clamping nut, the welding sleeve portion can be braced together with the heating elements against a tubular piece inserted in the welding sleeve portion. As a result, the pieces are fixed and supported before and during welding.

Adapting piece of thermoplastic material

A molded connecting piece has two saddle-shaped pieces one of which carries a hole drilling or punching tool and the other of which is connected to a branch line. The two connecting pieces are interconnected by an annular channel so that, when they surround are attached to a pipeline and a hole is made in the line, the medium reaches the branch line from the pipeline through the hole, through the annular channel and to the branch line. Between the saddle pieces and the pipeline are heating mats by which a tight welding connection can be produced.

Molded connection piece

A welded joint for plastic pipe is formed by apparatus including a sleeve (6) which is placed over the place where the pipes are joined and a heating mat (3) which is inserted between the sleeve and the pipes. The heating mat (3) and the sleeve (6) are provided with gear-tooth system (4, 5, 114, 115) which engage each other in the assembled condition of the device. Consequently, the surfaces of the ends of the heating mat (3) and the sleeve (6) which are in contact are circumferentially extended, resulting in a satisfactory welded joint, even where large pipe tolerances are involved.

Apparatus for welding a joint between plastic pipes

An apparatus for forming a weld connection with plastic pipe comprises two molded parts and two heating mats. Each part has an internal surface corresponding to a peripheral portion of the pipe being welded such that a cavity for receiving the pipe is defined by the internal surfaces. The parts are separated by longitudinally extending clearances. Each heating mat comprises a plastic coated resistance wire, is associated with one of the molded parts and has one of its end portions in one of the clearances. The mats completely cover the internal surfaces and the pipe periphery being welded.

Weld connection for plastic pipe

A welded joint for plastic pipe is formed by apparatus including a sleeve (6) which is placed over the place where the pipes are joined and a heating mat (3) which is inserted between the sleeve and the pipes. The heating mat (3) and the sleeve (6) are provided with gear-tooth systems (4, 5, 114, 115) which engage each other in the assembled condition of the device. Consequently, the surfaces of the ends of the heating mat (3) and the sleeve (6) which are in contact are circumferentially extended, resulting in a satisfactory welded joint, even where large pipe tolerances are involved.

A welding method for joining self-supporting structures made of thermoplastics by assembling said structures to form an area of mutual overlap, generating heat in said area to produce a welding zone having an elevated temperature and containing said thermoplastics in an at least plastic state for mutual coalescence of said structures in said area; an expanding agent is provided in the welding zone to generate a gas pressure therein for promoting coalescence of the weld. The invention is particularly suitable for welding tubes and other pipeline elements, such as fittings or sleeves, of thermoplastics and produces a tumescent weld which fills any macroscopic voids while including a plurality of minute closed cell voids.

Thermoplastics welding method

A coupling for smooth pipe includes a housing, a sleeve nut threaded onto the housing, a gasket inside the housing and a thrust and locking ring structure within and between the housing and sleeve nut. The housing has a tapered inner surface to compress the gasket. When the nut is threaded onto the housing, the ring structure is axially moved by a shoulder on the nut to compress the gasket. The nut then radially deforms tongues on the locking ring structure to grip the pipe.

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Uhwiesen, Switzerland

Fritz Reich