Usm Corporation

Farrel Corporation

Lefteris N Valsamis

Zehev Tadmor

Pradip S Mehta

Gary S Donoian

Peter Hold

Douglas V Poscich

Jose M Pereira

Eduardo L Canedo

Jan-Chin Yang

Multi-screw, extrusion-compounding machines having co-rotating screw assemblies incorporating sets of modular mixing elements of non-symmetrical geometries with relatively large wing tip clearances. These sets of non-symmetrical modular mixing elements are removably mountable at any suitable axial locations along their respective rotationally-driven screw shafts for optimizing performance in relationship to particular plastic material and particular additives being compounded. The non-symmetrical geometries provide dynamic wedging pressurization for repeatedly propelling relatively large circumferential flows of the plastic material through large shear clearances. Due to the relatively large shear clearances, the plastic material is mixed at less elevated and more uniform temperatures than usually occurs with use of prior symmetrical kneading blocks or kneading discs. At less elevated temperatures most plastic materials exhibit increased viscosities. Thus, the resultant increased viscosities enable the plastic material to be processed at higher shear stresses for enhancing dispersive mixing, in spite of the relatively large clearances which are being utilized. Thus, operators of extrusion-compounding machines are provided with desirable flexibility in adapting them for enhanced performance in matching machine processing functions with the processing characteristics and parameters of plastic materials and additives being compounded.

Multi-screw, extrusion-compounding machine with modular mixing elements

A rotary processor has enclosed processing passages defined by channels in the rotor and a stationary coaxial closure. At least one processing passage is used as a stabilizing passage and another as a metering passage, whose volume and cross section are less than the stabilizing passage. A feed of plastic or polymeric material enters the stabilizing passage and may be subject to fluctuations or disturbances arising in external upstream equipment or within upstream stages of the processor itself. Substantially all material in the stabilizing passage is diverted through a first transfer passage to an entrance into the metering passage. An adjustable metering (throttling) element allows a controlled first flow of material to be carried downstream through an adjustable gap between this metering element and the bottom of the metering passage. This controlled first flow is discharged for providing material having uniform flow or at least a marked reduction in such fluctuations and disturbances. The excess material which does not pass through the adjusted gap forms a recycled second flow which is returned back through a second transfer passage into said stabilizing passage for recycling. A modified embodiment shown as metering pumping apparatus includes pairs of stabilizing and metering passages sharing in handling throughput with adjustable throttling means for each metering passage. Interconnecting transfer passages equalize operation among these pairs. A transfer passage is also shown extending from an upstream processing passage to and past a metering passage to a stabilizing passage.

Rotary processor for plastic and polymeric materials providing surge

Novel rotary processors and devolatilizing methods which provide extremely efficient devolatilization of materials, including viscous and visco-elastic materials and which involve a devolatilizing stage including a rotatable element carrying a plurality of annular channels and a stationary element providing a coaxial closure surface operationally arranged with the channels to provide enclosed processing passages. Each passage of the devolatilizing stage includes inlet means, outlet means and a channel blocking member all associated with the stationary element and arranged and adapted so that material fed to the inlet can be carried forward by the rotatable channel walls to the blocking member for discharge from the passage. The passages are interconnected by material to transfer grooves formed in the closure surface and operationally communicate with a vacuum source to provide a highly efficient devolatilizing stage. The novel devolatilizing stage is characterized by features which provide control of the processing volume available within the passages and of the transfer volume available within the transfer grooves. These volumes may then be coordinated with other processing variables to effect a foam devolatilizing mechanism in which nucleation of bubbles of volatiles within the material, bubble growth and bubble rupture occur during substantially plug-flow movement alternating with non-pressurizing shearing within the novel devolatilizing stage.

Rotary processors for devolatilizing materials

Rotary processors and method for devolatilizing materials

Novel rotary processors which involve a devolatilizing stage including a rotatable element carrying a plurality of annular channels and a stationary element providing a coaxial closure surface operationally arranged with the channels to provide enclosed processing passages. Each passage of the devolatilizing stage includes inlet means, outlet means and a channel blocking member all associated with the stationary element and arranged and adapted so that material fed to the inlet can be carried forward by the rotatable channel walls to the blocking member for discharge from the passage. The passages are interconnected by material transfer grooves formed in the closure surface. The rotary processors of this invention include a novel vacuum system to evacuate the devolatilizing stage. A large manifold completely encloses a relatively large opening through the stationary element and communicates with a vacuum source through a relatively large vacuum port to simultaneously evacuate the passages of the devolatilizing stage at low vapor velocities. The novel vacuum system also includes means to effectively prevent material buildup at least in the region of the opening through the stationary element and the manifold.

Rotary processors and vacuum systems

Novel rotary processors including sealing means to control leakage of pressure and/or material between processing passages which are maintained at significantly different pressure levels. The processors comprise a rotatable element carrying a plurality of annular channels and a stationary element providing a coaxial closure surface operationally arranged with the channels to provide enclosed processing passages. Each passage includes inlet means, outlet means and a channel blocking member all associated with the stationary element and arranged and adapted so that viscous material fed to the inlet can be carried forward by the rotatable channel walls to the blocking member for discharge from the passage. The passages are interconnected by material transfer grooves formed in the closure surface. A sealing groove is carried by the rotor surface portions between two adjacent passages maintained at significantly different pressure levels, such as by evacuating one of the two adjacent passages, and is open to the clearance between the rotor and the closure surface. A gate at the inlet to the downstream pasasge pressurizes the material in the transfer groove interconnecting the two passages, and forces pressurized material in the sealing groove as it passes under the transfer groove. Helical grooves in the rotor portion on both sides of the sealing groove reinforce the pressure in the sealing groove and urge the material radially outward so that the material in the sealing groove contacts the closure surface about the entire circumference of the sealing groove, forming a continuous live O-ring seal in the clearance between the passages.

Rotary processors and seals

Novel and improved processes and apparatus for processing particulate materials which can be converted to the liquid state. Essentially, the process and apparatus involve feeding a particulate material to an annular processing passage for melting and controlled processing. The annular processing passage is provided by a rotatable element carrying at least one processing channel, and a stationary element which provides a complementary, coaxial surface arranged with the channel to provide the enclosed processing passage. Also associated with the stationary element are an inlet for feeding material to the passage, an outlet for discharging material, a material collecting end wall surface for the passage and a member or members extending into the processing channel providing a material restraining surface between the inlet and outlet and occupying a predetermined portion of the melt pool space between the end wall and the restraining surface. Rotation of the rotatable element establishes relative movement between the rotating inner channel wall surfaces and the restrained particulate material, causing only liquid (melted) material in contact with the rotating channel walls to be dragged forward to the end wall surface for controlled processing and discharge. Controlling the size of the melt pool space provides control of processing characteristics for the liquid material collected in the melt pool space.

Process and apparatus for processing plastic and polymeric materials

A novel, improved rotary processor comprising a rotatable element carrying a plurality of processing channels and a stationary element having a coaxial closure surface operationally arranged with the channels to provide a plurality of enclosed processing passages. The plurality of passages provide interconnected processing stages including a first processing stage and a second processing stage having inboard and outboard sections separated by a third processing stage.

Rotary processor

A multi-stage rotary processor particularly useful for processing plastic and polymeric materials. The multi-stage rotary processor includes a rotatable element carrying a plurality of processing channels and a stationary element providing a coaxial closure surface cooperatively arranged with the channels to provide a plurality of enclosed processing passages. Also associated with the stationary element are inlets, outlets and blocking members for each passage and arranged so that material fed to the passage can be dragged forward by the channel walls, and collected at the blocking member for discharge from a passage(s) of one stage to a passage of another. The geometry of the passage receiving material is selected to provide optimum processing efficiency, resulting in a processing rate capability for that passage greater than the rate at which material is supplied to the passage. Adjustable material transfer rate control means are arranged near the inlet of the material receiving passage so that the processing rate of the passage can be adjusted for coordination with the rate at which material is supplied to the passage.

Rotary processors

Novel, improved rotary processors which include a rotatable element carrying a plurality of annular channels and a stationary element providing a coaxial, closure surface operationally arranged with the channels to provide enclosed processing passages. The so-formed plurality of processing passages provide a highly efficient processing stage particularly for melting polymer material. Each processing passage of the processing stage includes inlet means, outlet means and a channel member associated with the stationary element and arranged and adapted so that material fed to the inlet can be carried forward by the rotatable channel walls to the blocking member for discharge from the passage. In rotary processors of this invention the clearance between the rotary surface carrying the channels and the stationary coaxial closure surface is relatively wide and permits substantial amounts of material to be interchanged between passages of the processing stage. The interchange provides especially efficient, intensive mixing for material processed in the stage. Also, the interchanged material which passes through the relatively wide clearance can be subjected to conditions of high shear and high temperatures.

Improved means for aligning processing members at various positions in processing passages of rotary processors. Essentially, the alignment means (or alignment elements) comprise a non-rotatable member positioned in the processing passage and shaped to at least partially interfere with flow of material in the passage. The shaped member is designed to perform certain processing functions on material in the passage such as blocking, collecting, mixing, spreading, restraining etc. The member is positioned so as to be non-rotative with the passage but is flexibly supported so as to 'float' axially in the passage and is self-centering in the passage by hydrodynamic action.

Processing element

A multi-stage rotary processor particularly useful as a pump for viscous materials. The multi-stage rotary processor includes a rotatable element having a surface carrying at least one primary processing channel connected to at least one further processing channel and a stationary element providing a complementary coaxial surface arranged with the channels to form enclosed primary and further processing passages. The stationary element also has associated with it an inlet for at least the primary processing passage, outlets for the passages and members extending into each channel for blocking material fed to the processing passages so that liquid material in contact with the rotating channel walls can be dragged forward in each channel. In the primary processing passage the dragged forward material is transferred to the further processing passage for discharge at a uniform pressure and rate.

Growing community of inventors

West Haven, CT, United States of America

Lefteris N Valsamis