Abstract: The present disclosure relates to a valve tray for use in a chemical process column. The valve tray includes a plurality of apertures formed therein. A plurality of valves are maintained in a spaced relationship relative to individual apertures of the plurality of apertures. An area of the individual apertures is less than an area of individual valves of the plurality of valves.

Abstract: An anti-pack out seal for use between fluid containing cylinders and pistons which are axially slideable therein and which extend through an opening in the end of such pistons. This seal has an annular channel adjacent to a resilient elastomeric seal ring, through which channel, an air stream containing an oil mist is circulated to remove solid particles of material which may separate or pack out from the fluid in the cylinder and in addition to prevent curing of the solid particles between the cylinder, the elastomeric seal and the bearing surrounding the cylinder.

Abstract: A metering unit (12) is attached to the robot (10) for providing two polymeric materials to a dispenser/mixer module (14) attached to the end of the robot arm (16). The metering unit includes piston (44) located concentrically about the shaft (42) of a dual actuating piston assembly (36) for providing the two polymeric materials in a fixed ratio. A variable rate dispenser (62) is provided for compensating for changes in robot velocity and/or viscosity changes.