Georg Fischer Aktiengesellschaft

George Fischer Limited

George Fischer Aktiengesellschaft

Streng Plastic Ag

Alfred Thalmann

Fritz Reich

Ernesto Lehmann

Emil Roth

Jurg Thalmann

Walter Gerber

Pipes to be joined and a pipe coupling have an outer sleeve made of a material optimized for linear and radial strength and positive connection and an inner portion or liner optimized for chemical inertness and the tightness of the connection. The pipes and coupling part are shaped to accommodate a material-correct joining procedure. Compound pipes (1) have a rigid, relatively thin pipe outer sleeve (3) for absorbing and transferring forces and a softer, relatively thin liner or inner pipe (4) to form a tight connection and inert sealing with respect to the rigid outer wall. Like the pipe, the coupling part (2) is made of a rigid joining outer sleeve (5) and a weldable socket (10), preferably made of the same material as the liner (1). Welding energy is introduced electrically. In order to cause a frictional connection on the one hand and a fluid-tight connection on the other between the two pipes, the inner pipe or liner projects beyond the outer part (3) by approximately half the length of the socket (10) at the joining point forming a free pipe end 9, which in the assembled state comes to rest in the electrically weldable socket (10). The outer sleeve on both ends of the coupling part (2) is shaped like a socket-like portion (6) so that following the introduction of the pipes into coupling part (2) it embraces the corresponding areas of the pipe outer sleeve. The full circumferences of free pipe ends (9) are welded in the vicinity of filament winding (12) and the coupling outer sleeve (5) is bonded frictionally to the pipe outer sleeve (3) in the vicinity of the socket-like portion.

Coupling for tubular plastic pipes with liner of socket and liner of

A cutting tool assembly including a pair of articulated arcuate strap members adapted to be clamped about a cylindrical pipe for cutting about the circumference of the pipe. A guide mechanism is provided including a pair of roller members engaged about the periphery of the pipe member to be cut and a guide part on a cutting tool, which guide part cooperates with the roller members.

Tool assembly for circumferential cutting of cylindrical pipe members

A prefabricated assembly for forming a high tensile strength pipe connection is formed by providing a metallic muff and pressing one end of a pipe adapter made from plastic material into the muff. The metallic muff has an internal diameter formed with sawtooth projections which penetrate the material of the pipe adapter and the penetration is enhanced by inserting a smooth support sleeve into the pipe adapter, the support sleeve being stiffer than the pipe adapter and operating to effect a positive and frictionally locking connection. The opposite end of the pipe adapter may then be attached by welding or the like with a plastic material pipe to form thereby a tight connection at a utilization site.

Prefabricated assembly for high tensile strength pipe connections

A system for heat-sealing thermoplastic conduits involves a thermoplastic sleeve surrounding an electrically conductive heating wire arranged in a coil. A bridging conductor is located adjacent the heating element, but is separated from it by an insulation layer of predetermined thickness. When the sleeve is heated by supplying electric power to the heating element, the entire heating element generates heat during a first phase in which fusion pressure is applied between the sleeve and pipes being connected. The bridging connector is forced into contact with selected coils of the heating element to initiate a second phase. In the second phase, the heat produced in the area of the selected coils is automatically reduced by short circuiting such coils.

Process for heat-sealing thermoplastic conduits

A molded tapping member for connecting a branch line to a pipeline includes a U-shaped saddle piece with a shell-shaped bight section and a pair of laterally spaced legs each extending outwardly from an opposite end of the bight section. The legs are formed of partial sections connected to one another by a film hinge. After positioning the tapping member on the pipeline by moving it radially toward the pipeline axis, the bight section and the legs are pressed around the pipeline. A heating wire mat is incorporated into the U-shaped saddle piece so that it fits closely around the pipeline for welding the tapping member to the pipeline. With the construction of this saddle piece a uniform welding pressure can be established during the welding operation.

Molded tapping member formed of a weldable plastics material

A heating wire embedded in any one of several types of shaped elements is fed current by an electrical control apparatus for a time interval which is a function of the ohmic resistance of the wire and the type of shaped element. The type and resistance are automatically determined in advance by measurement of the wire impedance which indicates type and of the ohmic resistance. Welding time is selected from a predetermined directrix depending on resistance, and the directrix itself is chosen on the basis of type by the impedance measurement. A count representative of the time is stored in a counter and pulsed down to zero while current is delivered.

Method and apparatus for welding conduits

A molded tapping fitting is made up of a saddle piece to be secured to a pipeline to be tapped, a tapping connection member and a branch connection line attached to the saddle piece. In combination, the saddle piece, the tapping connection member and the branch connection line form a chamber opening through the saddle piece into the pipeline. The interior of the chamber is shaped to facilitate the deflection of flow from the pipeline into the branch connection line.

Molded tapping fitting for connecting a branch line to a pipeline

Apparatus for the heat-sealing thermoplastic conduits with a bridging

An arrangement for welding together molded members consisting essentially of thermoplastic materials having abutting surfaces which extend generally parallel to each other at which a welding connection is made by electrical heat conductors located at the abutting surfaces. The electrical heat conductors are electrically activated to effect a welding operation and at least a plurality of the electrical heat conductors are connected in parallel with each other and are located between the abutting surfaces at which the weld is to be formed.

Arrangement for welding together thermoplastic molded members

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 pipe coupling or connection for plastic pipes, at least one of which has an end flange or collar, includes inner and outer rings having mating conical surfaces. The inner ring is plastic and is provided with a slit at one side and one or more thin hinge portions permitting it to be opened for placement over the pipe. The angle of the conical surfaces is chosen so that the resultant of clamping forces does not tend to tilt the rings or the pipe collar.

Flange connection

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 sleeve useable for connecting of pipes formed from thermoplastic material, is formed from a tubular body of thermoplastic material and a coil disposed on its inside surface. The coil has a resistance wire encased with thermoplastic material. The windings of the coil (4) are bonded into a compact coil which is inserted into the heated tubular body while it is simultaneously widened. As the result of a partial contraction of the tubular body also of the coil a firm connection develops between the oil and the body. Furthermore, the tubular body has a frozen-in, latent, radial contraction strain as a result of the widening, which during heating during the welding process, eliminates the radial play between coil and the pipes and produces a welding pressure.

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Uhwiesen, Switzerland

Alfred Thalmann