Feeder choke

Material Choke A mass of bulk solids or powders in a rotary valve or screw feeder that prevents a flame from being transmitted. 

A screw conveyor takes the comminuted raw material into a coaxial cylindrical chamber. On the left-hand side, this chamber features a reciprocating annular piston actuated hydraulically at a frequency of 120 strokes per minute to form a plug of compressed raw material serving as a pressure lock between the ambient atmosphere and the hydrolysis reactor. Due to its high frequency of operation, this feeder is likened to a machine gun. On the right-hand side, the chamber features a choke applying an adjustable pressure on the plug of raw material, and... 

Figure 290 illustrates some feeder designs that are used to obtain uniform distribution on wide rollers. Figure 290(a) is a choke-feed arrangement with tongue control. To feed the border zones of the rolls adequately the tongue is curved, thus restricting the flow of material to the center of the roll face more than toward the ends. 

The amount of material extracted from a flooded region by a screw feeder is mainly determined by the screw construction at the outlet end of the infeed region interface. The restraint offered by material in the clearance space between the flight tip and the casing as the screw leaves this region affects whether extra material is carried out by the boundary layer. This section of casing adjacent to the exit point of the screw from the supply hopper is termed the choke section . 

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