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: To eliminate the fluctuations in the precision of the material distribution which could not be avoided when manufacturing pipes in the centrifugal moulding process with the prior art installations, a new process and an installation for carrying out the process is proposed. This has at least two cylindrical centrifugal drums (1) serving as moulds and an injection carriage (12) which is displaceable in two directions perpendicular to each other, with a feed arm (11).

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: The bearing arrangement is suitable in particular for the mounting of molds for the production of plastic pipes by the centrifugal molding process. It has a ball bearing whose inner bearing ring (5) sits on the pipe (3) which is to be freely rotatably mounted and whose outer bearing ring (7) is held in a support ring (13). Covering rings, one (17, 19) of which on each bearing side is coordinated with the inner (5) bearing ring and one (11, 12) with the outer (7) bearing ring, serve for protection from water and humidity. These covering rings (17, 18, 11, 12) are such that, in pairs, they form a labyrinth seal. The covering rings (11) coordinated with the outer, i.e. the fixed, bearing ring (7) are provided with an injection nozzle (31) for lubricating oil and compressed air and with an outflow orifice (22) for water which has entered and a discharge orifice (36) for the lubricating oil.

Abstract: A tube coupling for coupling together one tube to another tube which have predetermined interior and exterior diameters comprises an outer sleeve which has an interior bore with a sealing element lining the bore of an elastic material. The sealing element has an exterior positively engaged sleeve and for this purpose advantageously includes exterior radially extending ribs which engage into dovetail radially extending grooves of the outer sleeve. The sealing element lining the bore of the tube is of an elastic material and it is formed substantially symmetrically in respect to its radial mid plane and includes at each end a plurality of inwardly directed sets of sealing protuberances following each other with cavities adjacent these protuberances into which the protuberances can be deflected by the engaged tube.

Abstract: A reinforced tube or a tubular pipe comprises an inner tubular first layer of glass fiber reinforced plastic, an outer tubular second layer disposed around and spaced radially outwardly from the first layer and also comprising a glass fiber reinforced plastic, and an intermediate filler layer located between the first and second layers and containing plastic and granular filler material which is bonded together and to said first and second layer. In addition a reinforcing insert is embedded in the intermediate filler layer and it comprises a continuous coil wound around the first layer and embedded in the intermediate layer. The coil may comprise a fiber reinforced plastic coil or a steel wire coil and a single one or two concentrically arranged coils may be embedded in the filler layer. The filler layer comprises plastic bonded granular material such as plastic and sand or an insulating material which may be made of an epoxy or a diphenyl polyester resin.

Abstract: A glass fiber reinforced multilayer pipe of plastic, comprises a wall having a plurality of plastic layers interconnected together and having a central wall axis with a median area on each side of the axis directly adjacent the axis and with an outer area radially outwardly from said median area, and an inner area radially inwardly of said median area. The plastic layers of the pipe wall include a plurality of glass fiber reinforced plastic layers and a plurality of plastic bonded granular filler material layers. The glass fiber reinforced plastic layers are provided both in the inner area and the outer area and the percentage of reinforcing glass fiber in the outer area is less than the percentage in the inner area. The ratio of the outer area glass fiber percentage to the inner glass fiber percentage is preferably 3 : 5.