Abstract: The subject of the invention is a method of manufacturing centrifuged, glass fiber-reinforced synthetic material pipes wherein liquid, curable resin, which contains a filler, together with glass fibers, additives for the curing process, possibly also with sand, is introduced into a rotating mould and the temperature of the mould is between 40° C. and 75° C. as the raw materials are introduced. The resin used in the layers in the outer region of the pipe has a gel time which is equal to or greater than the gel time of the resin used for the inner region of the pipe and the resin comprising a filler content of at least 40% is used. Furthermore, once the exothermal reaction has commenced, warm water is sprayed onto the mould in order to maintain the temperature of the mould at least at 60° C. until the pipe is removed.

Abstract: The invention relates to a method and installation for the purpose of manufacturing centrifuged glass fibre-reinforced synthetic material pipes, wherein liquid curable resin, which can contain a filler, together with glass fibres and additives for the curing process, possibly also with sand, is introduced into a rotating mould. With respect to the mould temperature as the raw materials are introduced, the quantity and type of additives are adapted in a successive manner such that gelling commences in the outer part of the pipe when the last part of the raw materials is introduced. Upon gelling, the temperature is lower in the outer part than in the inner part and gelling only commences in the inner part of the pipe after all of the raw materials have been introduced.

Abstract: A pipe coupling according to the invention comprises a socket (2) of glass-fiber reinforced plastics material and a membrane (4) of elastic material which is formed at at least one end as a seal and comprises a sleeve section (8). Where the membrane is formed as a seal, it has at the end where the pipe (20) is to be introduced (thus at the outer end), a short cylindrical band (14). In the cylindrical band the membrane has a constant wall thickness, which is backed by the glass-fiber reinforced socket material of the pipe coupling.

Abstract: The socket has an essentially cylindrical outer layer of glass fiber-reinforced plastic and a sealing sleeve arranged in a recess in the outer layer. This sealing sleeve has, between the two socket ends, a rib serving as a stop for the ends of the two pipes to be connected to one another. Here, the outer layer forms a first and a second hollow cylindrical, dimensionally stable edge section, the first of which is substantially longer than the second. That end of such a socket which is formed by the longer edge section can be pushed relatively easily onto a first pipe and can also be nondetachably bonded thereto by means of an adhesive. The second pipe having the same diameter can then be inserted into the socket end formed by the shorter edge section. Here, the relatively short edge section makes it possible to insert the second pipe into the socket with a tight seal even when the axes of socket and pipe do not coincide but make a small angle with one another.

Abstract: A rotating mold is fed with a flowable mixture of an inorganic filler material powder and a polyester resin for the purpose of generating or building up individual layers. By selecting the rotating speed during the layer buildup a more or less pronounced separation between resin and filler material is produced inside the layer, the value of the separation being selected in accordance with the specific application the component produced is intended to be used for. Subsequently the layer is fed cut glass fibers made to penetrate at least into the innermost resin-enriched region of the generated layer. Owing to this rotational-speed-controlled distribution of fiber material and resin inside the layers, larger values of mechanical strength may be obtained with reduced glass requirements. Any "strain-corrosion" may be avoided by using filler materials containing carbonate.

Abstract: The coupler consists of an essentially cylindrical outer layer of glass fiber-reinforced plastic and an inner layer consisting of polyurethane. This inner layer has, approximately in the middle between the two coupler ends, a rib which serves as a stop for the ends of the two pipes to be connected to one another. The coupler has, between this rib and one coupler end (a), an approximately conical inner shape which has a diameter which increases in an outward direction, this conical surface also being provided with two sealing beads.

Abstract: In a process known of per se for manufacturing plastic pipes, in which a liquid resin, a catalyst and sand and glass fibres are introduced into a centrifugal drum where the pipe is formed as the plastic sets, it was previously customary to start or stimulate the thermosetting process by blowing hot air into the centrifugal drum. The air escaping thereby from the inside of the drum contains solvent vapours which pollute the environment. The improved process consists in that the heat required to start the thermosetting process is no longer supplied from the inside by means of hot air, but by means of hot water which is sprayed onto the outside of the centrifugal drum and is fed through a hot water circuit and, after the exothermic thermosetting begins, heats up again in the latter to at least the original temperature, thereby drawing off heat released by the process. Further cooling is achieved by a cold water circuit, which can be switched on selectively to spray the centrifugal drum.

Abstract: A rotating mold is fed with a flowable mixture of an inorganic filler material powder and a polyester resin for the purpose of generating or building up individual layers. By selecting the rotating speed during the layer buildup a more or less pronounced separation between resin and filler material is produced inside the layer, the value of the separation being selected in accordance with the specific application the component produced is intended to be used for. Subsequently the layer is fed cut glass fibers made to penetrate at least into the innermost resin-enriched region of the generated layer. Owing to this rotational-speed-controlled distribution of filler material and resin inside the layers, larger values of mechanical strength may be obtained with reduced glass requirements. Any "strain-corrosion" may be avoided by using filler materials containing carbonate.