Abstract: Apparatus and methods for mixing plastic materials having different densities to supply a substantially uniform quantity of the mixture of such materials to an extruder or other processing machine. The mixture of materials is fed forcibly from the mixer to the processing machine by a variable speed auger. The mixture exerts a reactive force on the auger commensurate with the bulk density of the mixture. A sensor detects variations in the reactive force and produces signals which adjust the rate of rotation of the auger in inverse relation to the variations in the bulk density of the mixture to maintain the quantity of the mixture discharged from the mixer per unit of time within a selected range.

Abstract: Apparatus for drying plastic resin particles comprises a container, such as a hopper, for holding the resin particles to be dried and a first closed airflow loop communicating with the container for passing a heated airstream through the container to heat the particles and remove moisture therefrom. The heated airstream becomes moist and is returned to a plenum. A second closed airflow loop communicates with the plenum for receiving a portion of the moist return air under the control of an adjustable by-pass valve in the plenum. The second airflow loop includes a desiccant dryer communicating with the first airflow loop so that air dried by the desiccant dryer is mixed with moist air from the plenum for heating and return to the container.

Abstract: A plurality of individual plastic material ingredients are metered from respective individual material hoppers at controllable individual discharge rates, blended, and delivered to a common hopper. The blend of plastic material ingredients in the common hopper is discharged to an extruder or other material processing machine. The material processing rate of the processing machine is determined based on the sum of the discharge rates of the individual ingredients to the common hopper plus or minus the discharge rate of the blend from the common hopper to the processing machine. The discharge rates of the individual material ingredients from the individual hoppers to the common hopper is controlled as needed to maintain a preset recipe of the blend at the determined material processing rate of the processing machine.

Abstract: A blender for plastic materials weighs a charge of virgin plastic pellets as they are added to a hopper, similarly weighs plastics regrind material as it is added to the hopper, calculates the weight of color material (or other additive) on the basis of the actual virgin material weight and the desired color percentage, calculates from the weight of color material and a calibration of a volumetric feeder the volumetric amount of color material needed and then dispenses the calculated volume of color material. The apparatus is hybrid, using weight ratio measuring devices for the primary components and a volumetric feeder for dispensing the additives.

Abstract: Apparatus for controlling the discharge of fluent, particulate plastic material from a supply to a blending hopper comprises a delivery tube having a discharge orifice at its lower end that may be closed by a circular valve which seats against the delivery tube to close and seal the orifice. The valve is movable from its closed position to a fully open position in which a relatively large clearance exists between the discharge orifice and a body of material supported at its angle of repose on the valve. Material thus is able to cascade through the clearance to a receiving hopper whose weight is monitored by one or more load cells coupled to a microprocessor. When the weight of the receiving hopper increases to a selected value due to the delivery of material thereto, the valve is moved from its fully open position to a partially open position in which the aforementioned clearance is reduced substantially, thereby materially slowing the rate of discharge of material from the supply.

Abstract: An auger housing assembly for converging material along a path has a conduit within which is located a rotary auger. The conduit has at its lower side an elongate slot through which it may pass. Such slot normally is closed by a split sleeve member carried by the conduit and which is rotatable from a first position in which it covers the slot to a second position in which the slot is uncovered.

Abstract: Apparatus and methods for mixing fluffy scrap and rigid plastics materials for subsequent discharge of the mixture to an extruder comprises an upright mixing chamber to which rigid, fluent plastics pellets are fed by gravity and into which fluffy, ground scrap plastics material is fed by positive drive means from a hopper. Delivery of an adequate quantity of scrap material to the mixing chamber is assured by the provision in the scrap hopper of an agitating mechanism which is interposed between the top and the bottom of the hopper and which is operable to permit scrap material to pass downwardly to the bottom of the hopper for engagement by a feeding auger, but which prevents subjecting such scrap material to the weight of additional scrap in the hopper, thereby preventing bridging of the scrap at the lower end of the hopper.

Abstract: Apparatus for feeding plastic scrap and base material to an extruder comprises a scrap hopper to which scrap material is delivered for discharge through an outlet conduit leading to an extruding machine. The scrap plastic is fed through the conduit by means of an auger-like feed screw. Virgin or base plastic material is introduced to the scrap hopper outlet conduit and is mixed with the scrap prior to its discharge to the extruder. The base plastic material is delivered from a supply thereof to a receiver in which is an auger-like feed screw which feeds the base material into the scrap hopper outlet. At least the scrap feed screw comprises a rotary shaft having a discontinuous helical vane thereon constituted by a plurality of individual, segment-shaped members which are spaced longitudinally and circumferentially of the shaft.