Pipes centrifugal casting

Extracted from the American National Standard for Ductile-Iron Pipe, Centrifugally Cast in Metal Molds or Sand-Lined Molds, for Water or Other Liquids, ANSI A21.51—1976, with permission of the publisher, the American Society of Mechanical Engineers, New York. 

Centrifugal casting is used to produce water softener tanks and pipe by saturating a reinforcement with thermosetting resin within a mold that is then rotated at high speed to consoHdate the laminate before curing. 

Straight steel pipes up to 600 mm in diameter and six or more metres in length are usually lined by centrifugal casting. In this technique, the prepared preheated pipe is fitted with end caps and placed into the heated casting oven. Freshly mixed liquid polyurethane is then injected into the pipe which is then spun round its longitudinal axis until the polyurethane has cured to form a solid lining. 

A 451 Centrifugally Cast Austenitic Steel Pipe for High-Temperature Service... 

Figure 4.19. Layout of a unit for centrifugal casting (molding) of tubular blanks 1 - rotary mold 2 - mold rotation rollers 3 - heating chamber 4 - blank 5 - rotary gripper of finished pipe extender 6 - exhaust ventilation.

Although the polymerization of e-caprolactam was described above, there is no difference in principle from the process flow sheets for centrifugal molding of items from other polymers and oligomers. Nevertheless, in most cases, the high temperatures used in lactam polymerization are not required, and the flow sheet as a whole is simplified. In industrial practice, poly(methyl methacrylate) pipes,172 and sheets of polyurethanes and unsaturated polyesters are obtained by centrifugal casting. 

Centrifugal Casting. Reinforcing fibers are distributed inside a circular mold. The mold is rotated, and liquid resin is distributed inside it to impregnate the fibers. Rotation of the assembly is continued inside an oven until it is cured. This process is used for making pipes, tanks, and hoops. 

There is a modified centrifugal casting process that produces continuous filament reinforced TP pipes/tubes with precise fiber placement and smooth internal and external surfaces. TPs such as nylon and polypropylene have been reinforced with fibers such as glass and carbon. Products such as automotive drive shafts and bearings have been fabricated with fiber volumes up to 60wt%. These tubes have very low rotational unbalances and tight tolerance of wall thickness (Chapter 15). 

Fused cast basalt is cast in many shapes. Standard flat surfaces can be lined with square or rectangular standard flat tiles. Cylinders for pipe systems are made in static or centrifugal casting procedures. Wall thickness ranges from 21 mm for centrifugal spun cast cylinders to 30 mm thickness for the statically mold cast cylinders and tiles. Thicker liners can also be made. 

Fused basalt is utilized chiefly in the manufacture of floor tiles, castings for cyclone and other separators, nozzles, augers and grate bars the centrifugal casting technology is used in the production of conveyor pipings for mines, mill corps, etc. A special case is represented by the application of fused basalt for the incorporation of radioactive wastes. Fused rocks are dealt with in the extensive series of studies by Voldan (1955 — -1976). 

Atlac . [Reichhold/Reactive Polymers] Thermoset polyester resins for fiberglass-reinforced structures, glass-reinforced coatings, mortars in pulp and paper, caustic-chlorine, metal treatment, filament winding, centrifugal casting of large tanks and pipe. 

Filament wound Centrifugally cast — Other piping... 

As reviewed, the mechanical properties of centrifugally molded pipe and 55° filament wound pipe are much more resin dependent than typical custom engineered pipe. With centrifugally cast pipe, the tensile properties are very resin dependent because the fibers are chopped into relatively short lengths. It is subjected to creep and time-loss of mechanical properties. In addition, resin properties drop radically with temperature especially near the glass transition temperature. 

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