Heated mandrels

The uncured wool from the forming conveyor is separated into pelts , which are converted into pipe sections by being wrapped around a heated mandrel, and the wall thickness set by counter rollers. The sections are then passed through a curing oven before being trimmed, slit, covered and packaged. 

A furnace containing a graphite mandrel on which deposition is to occur is used to produce massive pieces of pyrocarbon for rocket nozzles and nose cones. Hydrocarbon gas such as methane, natural gas, or propylene is diluted with an inert gas and introduced into the furnace containing the heated mandrel, whereupon pyrocarbon is deposited on its surface. In this case difficulties arise because there is no mixing of the gas and there are large gradients in the temperature and composition of the gas. For example, as the gas progresses down the tube the concentration of hydrocarbon is depleted because of the carbon deposition therefore the amount and the structure of the deposit vary with position. 

In a filament winding process the filament is applied on a mandrel. Mandrel types can be distinguished in heated mandrels, non-heated mandrels, dissolvable cores and liners. Using a heated or non-heated mandrel the quality of the mandrel surface is an important factor due to the fact that the finally wound component must be stripped (pulled or pushed) over the surface. By using a liner or a dissolvable core the surface quality is not so relevant, due to the fact that the liner remains in the product and the dissolvable core is removed after the winding process. 

The temperature distribution in a winding process with a non-heated mandrel is not homogeneous over the whole winding duration. At the beginning of the process the mandrel has an ambient temperature which increases during the winding due to the heating by the main heater and the heated... 

The second approach allows the production of cylindrical objects, such as flywheels for energy storage. A filament winding procedure has been developed in which resin-impregnated fibers are wound onto a heated mandrel at a rate that matches that of the expanding cure front. Korotkov et al. (1993) proposed a model for such a process. 

By properly designing furnace hardware and controlling the deposition process, pyrolytic graphite can be manufactured commercially as solid plate, cones, tubes and other free-standing shapes. Because the deposition process relies, in part, on diffusion of the hydrocarbon gas to the heated mandrel, it also is possible to densify porous... 

The Stedman-type column is shown in Fig. 11, 56, 25. The characteristic features are (i) the use of a fine stainless steel wire cloth formed into conical discs, and (ii) an accurately fitting Pyrex glass jacket, produced by shrinking Pyrex glass on mandrels to the required inside dimensions. Modifications incorporating a silvered vacuum jacket and an electrically-heated jacket are marketed. This column is said to possess high efficiency but is expensive. It is generally employed in conjunction with a total-condensation variable take-off still head. 

The cod wound heat exchanger consists of multiple tubes heHcally wound on a mandrel, usually with spacers between each tube layer. The tubes are inserted into tube sheets at both ends of the tube bundle, with separate tube sheets to accommodate each tube circuit. The tube bundle is enclosed ia a sheU with inlet and outlet no22les for the sheUside fluid. This type of heat exchanger is usually constmcted of aluminum or stainless steel. Large aluminum... 

Process in whicli continuous strands of roving or roving tape are wound, at a specified pitch and tension, onto the outside surface of a mandrel. Roving is saturated with liquid resin or is preimpregnated with partially cured resin. Application of heat may be required to promote polymerization. 

The method of vulcanising those rubber products which do not require the precision of shape given by a mould. The heat for curing is supplied by steam circulating openly in an autoclave, the products being supported on mandrels or embedded in chalk. See Moulding. 

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