Monofilament fiber equipment

Because high pressures and even fiber diameters are generally required for monofilament fiber spinning, a metering pump is placed between the extruder exit and the spin die. A typical pressure at the exit of the extruder is 7000 kPa (1000 psi) to 21 000 kPa (3000 psi), which is used to feed the inlet to the metering pump. 

A standard gear pump can have one or more exit streams as needed. Each stream has a constant volumetric output based on the rotational speed (RPM) of the gears. The gear pump is driven by an AC motor with inverter or vector drive speed control. The exit pressure from a metering pump in a typical spinning process will range from approximately 7000 kPa (1000 psi) to 25 000 kPa (3500 psi). Once the pressure reaches 25 000 kPa (3500 psi), the process is typically shut down and the filter media replaced. 

The last device in the extrusion process is the spin head. The spin head consists of a pump block, heating device, and spin packs. The metered polymer from the extruder flows to the metering pump and into the spin pack. A heated housing surrounds the pump block, metering pump, and spin pack to maintain all the equipment that comes into contact with the polymer at the desired temperature required for proper extrusion of the polymer. 

The spin pack contains filter media such as screens or shattered metal, which is used to filter the polymer before it goes to the spinneret (Reifenhauser GMBH and CO., 2011). The spinneret contains one or more holes of precise diameter and length to spin the polymer and form a fiber 

After stretching, most polymers need to be heated to a temperature that will crystallize or heat-stabilize the filaments. This needs to be done under a different tension and at a higher temperature than used in the draw step. Therefore, after exiting the draw rolls the filaments travel through a final heat oven and exit into a final set of roUs. These rolls generally are run at a slightly lower (1-5%) speed than the draw rolls. This reduces the tension in the yarn as the heat setting occurs. The final properties of the filaments are now complete. 

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Melt Processing. Vinylidene chloride copolsrmers are melt processed via a variety of fabrication techniques. These include molding, monofilament fiber extrusion, monolayer blown film extrusion, multilayer cast- and blown-film extrusion, and multilayer sheet extrusion. There are a number of elements of melt processing and melt-processing equipment that are common to all of these fabrication techniques (184 187). These include proper equipment design and materials of construction, proper and accurately controlled operating conditions, and a properly formulated resin. 

Early in the manufacture of PP, a concept was developed for dry spinning directly from the solution obtained in the polymerization operation. Had it been feasible, it would have been the realization of a chemical engineer s dream the gaseous olefin fed into one end of the equipment, and the packaged fiber, ready for shipment to a textile mill, coming out the other end. But it did not turn out that way, and today melt spinning is the accepted technique for the production of staple fibers, monofilament, and multifilament yams. To this usual method have been added the fibrillation and the slit film procedures for producing yams. 

Establishments primarily engaged in manufacturing cellulosic fibers (including cellulose acetate and regenerated cellulose such as rayon by the viscose or cuprammonium process) in the form of monofilament, yarn, staple, or tow suitable for further manufacturing on spindles, looms, knitting machines, or other textile processing equipment. 

The current version ( ) of the fiber treatment process employs a drawing rig equipped with a solvent treatment tube where an as-spun PET monofilament briefly contacts a swelling agent, causing rapid crystallization of surface layers. Solvent exchange and drying steps quench the crystallization before the fiber is drawn between feed and take-up rolls. A skln/core morphology results... 

Silicon carbide (SiC) monofilaments are usually made by chemical vapor deposition (CVD) by decomposing a silane such as methyltrichlorosilane (CHjSiCy in a hydrogen atmosphere onto a hot and fast-moving tungsten wire or pyrolitic carbon monofilament at a temperature of 1300°C. The equipment and process is the same as that used for making boron fibers (see Section 18.4.2). The chemical reaction occurring at the surface of the hot substrate is ... 

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