Feed port design

Smith, W.S., Sickles, R.A., Miller, LA., and Womer, T.W., An Experimental Investigation into Solids Feeding Characteristics of a Single Piece Barrel with Integral Feed-port Design vs a Standard Two Piece Water Cooled Feedblock and Barrel Configuration, SPE ANTEC Tech. Papers, 53, 390 (2007)... 

Figure 5.11 Feed port designs (a) standard feed port (adapted from Refs. 31 and 32), (b) undercut feed port (adapted from Refs. 31 and 32), (c) sloped feed port (adapted from Ref. 31), and (d) tangential feed port (adapted from Ref. 32).

The geometry of the feed port should be such that the material can flow into the extruder with minimum restriction. Cross-sections of various feed port designs are shown in Fig. 3.11. 

Through-hardened design especially for housing with several feed ports, e.g., made of wear-resistant tool steel or wear- and corrosion-resistant chrome steel. This design is often constrained by the size of the component because heat treatment can cause stress cracks in cross sections with thick walls. 

The micromodel is located in the mid-section of the pressure vessel. It is seated in a slot where the feed ports exit the mid-section and is clamped down by restraining bars. The holes tapped in the micromodel are aligned with the feed port exits, and a seal is maintained by 0-rings seated around these exits. This design differs from the Campbell-Orr pressure vessel which uses tubing fitted to C-clamps to carry fluids to and from the micromodel. The design employed here restricts the size of the micromodels to a particular set of specifications, but does provide a more secure way of pressurizing the micromodel. 

The fuel solids are fed into the fluidized bed by means of a screw conveyor with a specially designed feeder valve. The feed port is located 5 inches above the gas distribution plate. The 2 -inch screw is constructed of carbon steel with a Type 310 stainless steel coating on the wearing surfaces. The construction details of this feeder and the auxiliary solid feed hopper system have been described by Burton and Bailie (2). The feeding unit has performed successfully in smoothly feeding 15-60 lbs of solids/hr into the fluidized bed. 

Some extruders are designed to permit feeding at more than one location of the extruder, and therefore contain multiple feed ports, each with its own hopper. This permits, for example, fillers to be introduced into the extruder after the plastic resin has already been melted. 

The process flow layout for the twin-screw mixer set up is presented in Figures 3.12 and 3.16. As noted above, the metering screws for feeding powder, rubber, and pellets would each have a different design, each optimized for trouble-free smooth delivery of the blend components. The rate is affected by the ability of the feed port to handle the bulky compounds. In reality, this is often the limiting factor in production of blend compounds that have fluffy fillers. 

The roaster feed system consists of four slurry feed ports, three operating and one standby, mounted to the roof of the roaster. Each feed port consists of a single nozzle used for atomization of slurry feed with plant air. Design includes control over atomization air flowrate and pressure and an installed purge air delivery system for the prevention of dust ingress to the gun. 

In this design, the feed port is combined with the vent port. The volatiles are removed through the annular space between the feed pipe and the feed port housing. The system is used in conjunction with a vacuum feed hopper as described by... 

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