Patent Publication Number: US-7593830-B2

Title: Controlled material processing method

Description:
This application is a division of Stanton et al. Ser. No. 11/557,671, filed Nov. 8, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a material processing control system and method, in particular for controlling a viscous material processing system. 
     In a viscous material processing system, feed is mixed and additives are injected in precise proportions to produce a customized product. The system requires exact and reliable dosing and feed operations to achieve uniform products with narrow tolerance properties. Accurately metering the material in a feed step can be critical to proper system operation. 
     However, it is difficult to accurately process a viscous material. The material only slowly responds to change in feed rate. The material may be resistant to pouring or if it can be poured, pour rate can be extremely slow. The material may exhibit high levels of adhesion or tendency to stick to other materials and/or cohesion or a tendency to remain stuck to itself and therefore resistant to separation. The material may be shear thickening, exhibiting increasing viscosity as shear on the material is increased. These properties present problems to process control. 
     Accurate quantities of the material are difficult to separate from a bulk of the material and are difficult to accurately process. Accordingly, there is a need to control processing of such material. Also, there is a need to accurately cut defined quantities of such material from a bulk quantity, regardless of the form of the bulk quantity and there is a need to accurately charge a viscous material to a processing system. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention provides a system and method to control processing of viscous materials. 
     The invention can be described as a viscous material processing system, comprising: a feed system controller having a set of instructions to store an input set point weight or amount; sense a progressing weight or amount of material fed by the feed system; compare the progressing weight with the set point weight or amount and terminate feed from the system when the compared progressing weight is substantially equal to the set point weight or amount; and a viscous material compounding system connected to the feed system to receive material fed by the feed system. 
     In an embodiment, the invention is a data processing device, comprising: a reader to read a sensed weight or amount of material fed to a material compounding system; a comparator to compare the sensed weight or amount with a stored set point weight or amount; and a regulator to terminate feed of material to the material compounding system when the compared sensed weight or amount is substantially equal to the set point weight or amount. 
     In another embodiment, the invention is a computer implemented method, comprising: storing an input set point weight or amount, sensing a progressing weight or amount of viscous material fed by a feed system; comparing the progressing weight with the set point weight or amount; and terminating feed from the system when the compared progressing weight is substantially equal to the set point weight or amount. 
     In still another embodiment, the invention is a viscous material feed method, comprising: determining an initial weight of a combined feed system, container and viscous material held within the container; evacuating viscous material from the container by the feed system for charge to a viscous material compounding process; monitoring a weight of the combined feed system, container and viscous material held within the container as material is evacuated; determining a progressing weight or amount of material fed by the feed system according to a difference between the initial weight and the monitored weight of the combined feed system, container and viscous material held within the container as material is evacuated; and controlling a rate of cutting viscous material that is evacuated from the container for feed to the viscous material compounding process according to the determined amount of charged viscous material. 
     In still another embodiment, the invention is a computer implemented viscous material feed method, comprising: determining an initial weight of a combined feed system, container and viscous material held within the container; evacuating viscous material from the container by driving a platen through a longitudinal axis of the container to express viscous feed material from the container to a material compounding system; monitoring a weight of the combined feed system, container and viscous material held within the container as material is evacuated; determining a progressing weight or amount of material fed by the feed system according to a difference between the initial weight and the monitored weight of the combined feed system, container and viscous material held within the container as material is evacuated; and controlling a rate of cutting viscous material that is evacuated from the container for feed to the viscous material compounding process according to the determined amount of charged viscous material. 
     In still another embodiment, the invention is a computer implemented data processing system, comprising: reading a sensed weight or amount of material fed to a material compounding system; comparing the sensed weight or amount with a stored set point weight or amount; and terminating feed of material to the material compounding system when the compared sensed weight or amount is substantially equal to the set point weight or amount. 
     In another embodiment, the invention is a silicone gum feed system, comprising: a drum press located on a loss of weight scale; a feed tube that receives material expressed from a drum by the drum press; a cutting apparatus that meters material from the feed tube to a processing system according to loss of weight sensed by the scale; and a controller with a set of instructions to store an initial weight, monitor a continuing weight, determine weight of silicone gum fed to the processing system according to a difference between the initial weight and the monitored weight and controlling a rate of the cutting apparatus according to the difference. 
     In still another embodiment, the invention is a computer implemented data processing method, comprising: registering a material feed session set point weight or amount range defined by a first set point weight or amount and a second set point weight or amount; driving a material feed system to feed viscous material in the session by cutting a steadily moving material into increments that feed sequentially to a compounding system; monitoring a session total of material fed to the compounding system; comparing the session total of material to the session set point weight or amount range; increasing a cutting rate of material increments to decrease each cut increment quantity when total material is substantially equal to the first set point weight or amount of the session set point weight or amount range; and terminating the material feed of the session when the total material is substantially equal to a second limit of the set point weight or amount range. 
     And in another embodiment, the invention is a material feed system, comprising: a material extracting apparatus; and a controller with a set of instructions: to (i) refer to a look-up data base to determine a set point weight or amount for a material to be charged to a compounding system; (ii) sense an initial combined weight of a material extracting apparatus and a container with material; (iii) signal commencement of operation of the material extracting apparatus to evacuate material from the container; (iv) sense a progressing combined weight of the material extracting apparatus and the container with material; (v) calculate a charged material weight according to a difference between the initial combined weight and the sensed progressing combined weight; and (vi) terminating the material extracting apparatus operation when a calculated charged material weight is within a predetermined range of the set point weight or amount. 
     In another embodiment, the invention is a computer implemented data processing method to feed a material compounding system, comprising: referring to a look-up data base to determine a set point weight or amount for a material to be charged to the compounding system; sensing an initial combined weight of a material extracting apparatus and a container with material; signaling commencement of a material extracting apparatus operation to evacuate the material from the container; sensing a progressing combined weight of the material extracting apparatus and the container with material; calculating a charged material weight according to a difference between the initial combined weight and the sensed progressing combined weight; and terminating the material extracting apparatus operation when a calculated charged material weight is within a specified range of the set point weight or amount. 
     And in still another embodiment, the invention is a controller for a feed to a compounding system, comprising: a set of instructions to read a material feed session set point weight or amount; to direct feeding a viscous material in the session by cutting a steadily moving material into a portion that feeds sequentially to the compounding system; to monitor a session total of material fed to the compounding system; to compare the session total of material to the session set point weight or amount; to increase a cutting rate of the moving material to decrease each cut increment of material as the session set point weight or amount is approached; and to terminate the material feed of the session when the total material is substantially equal to the session set point weight or amount. 
     And in another embodiment, the invention is a silicone gum processing system, comprising: a silicone gum compounding system; and a viscous material feed system to the compounding system, the feed system comprising a cutting apparatus that cuts material according to weight of material charged to the compounding system as monitored by a controller having a set of instructions to decrease a weight or size of cut material increments fed to the compounding system as a feed session set point weight or amount is approached and to terminate the feed to the compounding system when the session set point weight or amount is attained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 ,  FIG. 2  and  FIG. 3  are schematic representations of a material processing system; 
         FIG. 4  and  FIG. 5  are perspective views of a drum press; 
         FIG. 6  is a cut away view of a section of a drum press; and 
         FIG. 7  is a flow diagram of a control process. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention relates to the handling of a viscous material such as a silicone gum. “Silicone gum” includes a viscous silicone or polysiloxane or organopolysiloxane that has the chemical formula [R 2 SiO] n , where R=organic groups such as methyl, ethyl, and phenyl. These materials typically comprise an inorganic silicon-oxygen backbone (. . . —Si—O—Si—O—Si—O— . . . ) with attached organic side groups, which can be four-coordinate. In some cases, organic side groups can be used to link two or more of these —Si—O— backbones together. 
     By varying the —Si—O— chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. They can vary in consistency from liquid to gel to rubber to hard plastic. Silicone rubber or silicone gum is a silicone elastomer, typically having high temperature properties. Silicone rubber offers resistance to extreme temperatures, being able to operate normally from minus 100° C. to plus 500° C. In such conditions tensile strength, elongation, tear strength and compression set can be superior to conventional rubbers. 
     A silicone gum can be extruded or molded into custom shapes and designs such as tubes, strips, solid cord or custom profiles within size restrictions specified by a manufacturer. Cord can be joined to make “O” Rings and extruded profiles can also be joined to make up seals. 
     It is desirable to provide a viscous feed system that accurately and efficiently processes viscous materials such as silicone gum for use in various applications. However, these materials can be highly resistant to flow, highly adhering, highly cohering, and/or shear thickening and consequently difficult to handle. Accuracy of a packaging process and/or accuracy of a process of obtaining a defined quantity of such material, for example in a continuous process, is costly when substantial time is required for cutting or separating a quantity of the material from a larger quantity. Also, it is costly and disadvantageous when an incorrect amount of material is used in a downstream process. 
     The invention provides a system and method to control processing of viscous material. Features of the invention will become apparent from the drawings and following detailed discussion, which by way of example without limitation describe preferred embodiments of the invention. In this application, a reference to “back” means left on a drawing or drawings and a reference to “forward” means right on the drawing or drawings. 
     A preferred embodiment shown in the drawings, illustrates the invention as a process to compound silicone gum into a base for forming articles. In the drawings,  FIG. 1  is a schematic top view representation and  FIG. 2  is a schematic side view representation of a section of a material processing system showing an integrated feed system  12  and compounding system  14 . The feed system  12  includes a battery of material extracting apparatus (MEA)  16 , conveyor  18  and chute  20 .  FIG. 4  and  FIG. 5  are elevation views of an MEA  16  and  FIG. 6  is a cut away side sectional view of a section of the MEA  16 . The MEA  16  includes container evacuator  22 , feed tube  24 , cutting apparatus  26  and floor scale  28 . The integrated feed system  12  is controllably connected to controller  30 .  FIG. 6  is a cut away view of an upper section of the drum press, MEA  16  of  FIG. 4  and  FIG. 5 . As shown in  FIG. 1 ,  FIG. 2  and  FIG. 3 , compounding system  14  includes mixer  32 , roll mill  34 , conveyor belt  36  and compounder  38 . 
     The MEA  16  serves to express the viscous material from a container to the compounding system  14 . In typical operations, 55-gallon steel drums  42  from a pallet  40  are dumped into totes and the totes (approx. 80 pounds each) are dumped into a Banbury mixer. In a preferred compounding operation of the invention with respect to  FIG. 1 ,  FIG. 2  and  FIG. 3 , operation commences with delivery of a pallet  40  of four drums  42  of gum. While the drum  42  can be any material holding enclosure, the drawings embodiment is a feed system including a method of evacuating a silicone gum-containing drum  42 . A suitable drum  42  in the embodiment, has full openable ends and has a cylindrical wall of steel, fiberboard or other material structure for transporting a silicone gum material. The drum  42  has opposite ends, each of which is openable to accommodate a movable plunger at one end as hereinafter described. 
     The material in the drums  42  may be identical or it may be of a variety of physical properties such as viscosity. The drums  42  are removed from the pallet  40  one by one by drum hauler  44  such as from Easy Lift Equipment Co., Inc., 2 Mill Park Court, Newark, Del. 19713. The lid of each of three drums  42  is removed and each of the drums  42  is loaded by the hauler  44  into a respective container evacuator  22 , which may be a Schwerdtel S 6-F drum press. Use of the drum hauler  44  eliminates ergonomic risks associated with lifting and handling the heavy drums  42 . The silicone gum is then forced from each drum by an MEA  16  into the conveyor  18 . In the drawings embodiment, an MEA  16  comprises a container evacuator  22 , feed tube  24  and cutting apparatus  26 . The container evacuator  22  can be a drum press, which is a device that evacuates viscous or compacted contents from a drum. 
     As illustrated in  FIG. 2 ,  FIG. 4  and  FIG. 5 , the container evacuator  22  is a press that comprises a substantially cylindrical chamber  50  with hinged enclosures  52  and  54  for securing a drum  42  removably within the chamber  50 . The chamber  50  and hinged enclosures  52  and  54  securely cradle the drum  42  during a material extracting operation. A disc-shaped platen  56  fits into the chamber  50  with a flat driving surface  58  ( FIG. 6 ) oriented perpendiculars to the longitudinal axis of the chamber  50  and correspondingly perpendicular to the longitudinal axis of a drum  42  held within the chamber  50 . 
     The operation of feed system  12  can be described with reference to  FIG. 1 ,  FIG. 2 ,  FIG. 4 ,  FIG. 5  and  FIG. 6 . In operation, the press enclosures  52  and  54  are unlatched by activating fasteners  110  to open enclosures  52  and  54 . The drum hauler  44  is used to load a first drum  42  into the press cavity  60 . The drum  42  is positioned by a locator ring  62  at the base  64  of the chamber  50 . The press enclosures  52  and  54  resist axial expansion pressure exerted by plunger  72  driving through drum  42 . The enclosures  52  and  54  are secured by a plurality of fasteners  110 . 
     Each MEA  16  includes the container evacuator  22 , feed tube  24  and cutting apparatus  26  and cage  66  and each is set on a respective floor scale  28 . In each MEA  16 , the feed tube  24  is connected through the disc shaped platen  56  ( FIG. 6 ) to communicate with the press cavity  60 . The platen  56  is driven by hydraulic plunger  72 . 
     An operator can commence system operation at controller  30 . When a cycle is activated by the operator, a plunger  72  of each container evacuator  22  of the battery shown in  FIG. 1 , is activated via control lines  84 .  FIG. 4  shows connecting sections  74  of control lines  84  to MEA  16 . Then, as the screw conveyor  18  starts turning, the press platen  56  with connected feed tube  24  is forced by hydraulically driven plunger  72  to travel down into the drum  42  interior. As further illustrated in  FIG. 6 , as platen  56  traverses the drum  42  longitudinal axis within the press cavity  60 , drum contents are displaced upward into a connecting orifice  68  of the feed tube  24 . As the platen  56  completes traversing the drum axis, all material is forced upward into the feed tube  24  to be eventually expelled from the feed tube discharge port  70 . 
     The material is cut into increments by cutting apparatus  26  as it exits from the discharge port  70  to the conveyor  18  to charge to compounding system  14 . Cutting can be accomplished by various cutting mechanisms, including a cutting head disposed at an outlet end, port  70  of the feed tube  24 . In the  FIG. 4 ,  FIG. 5  and  FIG. 6  embodiment, the MEA  16  includes a cutting apparatus  26  located at discharge port  70 . The cutting apparatus  26  includes rails  80  that secure cutting wire  82  to guide the wire  82  to cut material exiting the feed tube discharge port  70 . The rails  80  secure the cutting wire  82  to traverse the feed tube  24  longitudinal axis at discharge port  70  when activated by controller  30  via lines  84  ( FIG. 1 ). 
     The controller  30  of  FIG. 1  illustrates an embodiment of the invention. Controller  30  is responsively connected to loss of weight scales  28  via lines  92  to sense loss of weight as material is expressed from the drums  42  to conveyor  18 . The controller  30  computes a weight of material charged to the conveyor  18  by the difference between an initial weight of the MEA  16  and initially emplaced and full drum  42 . In the embodiment of the drawings, the controller  30  can sense an initial total weight of all the MEAs  16  and emplaced full drums  42  of the MEA battery of for example, the three shown in  FIG. 1 . The controller  30  monitors the combined weight as material in the drums is evacuated to the conveyor  18 . The controller  30  contemporaneously calculates a weight of material charged to the conveyor  18  and hence to the compounding system according to a difference between the initial total weight and contemporaneously sensed total weight. 
     The controller  30  also can control operation of cutting apparatus  26  according to the calculated charged material weight. Initially, the cutting apparatus  26  can be programmed to make cuts of about “football” sized material, for example to fit into a 14″ inner diameter screw conveyor  18 . Once a piece of material is cut from the feed tube discharge port  70 , floor scale  28  senses a contemporaneous weight and feeds this signal back to the controller  30 . The controller  30  controls the material processing system  10  according to “set points.” In this application, a “set point weight or amount” is a target quantity or amount of material to be fed from a feed system, usually in a feed session. In one embodiment, “set point weight or amount” means a point weight or amount at which the feed session is to be terminated. In another embodiment, as the controller  30  senses a contemporaneous weight signal and calculates that a total charged weight is within a specified range of total material to be charged (for example within 15 pounds of “set point weight or amount”) to the compounding system  14 , the controller can signal the cutting apparatus  26  via lines  84  to increase cut frequently to produce smaller incremental pieces. The smaller pieces at approach to set point weight or amount permit improved control of feed to attain a charged material weight within a prescribed tolerance range, for example ±2 pounds for a batch. 
     As the drum  42  evacuation process is completed, door fasteners  110  of the hinged enclosures  52  and  54  open and a controller  30  Run Screen can display “NEW DRUM.” A beacon light mounted on the container evacuator  22  can turn yellow, indicating another drum  42  is ready to be changed. The hydraulic platen driving motor terminates and the chamber  50  enclosures open. The evacuator  22  is reloaded with a drum and the process repeated. As material is charged from the MEAs  16  to the screw conveyor  18 , the conveyor is turning at low rpms to feed the material to the mixer. The screw is programmed to stop turning 90 seconds after the last MEA  16  makes its last cut. This time can be adequate to clear all material from the conveyor  18 . 
     As material is charged from the MEAs  16  to the screw conveyor  18 , the conveyor is turning at low rpms to feed the material to the mixer. The conveyor screw is programmed to stop turning 90 seconds after the last MEA  16  makes its last cut. This time can be adequate to clear all material from the conveyor  18 . 
     Conveyor  18  transports and drops the cut viscous material to chute  20  to compounding system  14 , which includes mixer  32  such as a Banbury, roll mill  34 , conveyor belt  36  and compounder  38 . In the mixer  32 , fumed silica, the silicone gum and a treating agent can be added to form a densified polymer/filler mass. After the gum feed is mixed, it is dropped into the nip of roll mill  34  where the material is rolled into a strip form. After a drop, a programmed logic controller (PLC), for example controller  30 , verifies that the mixer drop door has opened, then reclosed and is ready for feed. For any residual material that hangs in the chute, a “pusher” is programmed to sweep a few seconds after the conveyor  18  stops. This serves to scrape down the chute  20 , and ensure all material gets into the mixer  32  to correctly formulate the batch. 
     The mill imparts a final mix to fully incorporate filler and to cool material. Then, the material is stripped from the mill in a strip form. The strip form is fed by means of conveyor belt  36  into compounder  38 , which may be an extruder. The compounder  38  serves to clean and form the material for packaging. The material can be packaged and boxed through an automated cut, weigh and packaging system. 
     The controller  30  of  FIG. 1  can be a microprocessor, computer, data processing device, semiconductor chip or the like.  FIG. 7  is a flow diagram of a preferred embodiment control system  400  of the invention. The  FIG. 7  signal processing can be incorporated by controller  30  to control a material processing system as follows. 
     At a session start  401 , input values, Σ 1  and Σ 0  that are set point weights or amounts are input  403  into the control system  400 . Input value Σ 1  represents a first target value of material that triggers a change in a charging rate of material to the compounding system  14 . Input value Σ 0  represents a target total material to be charged in a session to a compounding system, for example to the compounding system  14  via conveyor  18  of  FIG. 1 . A session is a period defined by a time or quantity of material to be charged to the processing system  400 . The time or quantity may be determined by an amount of a contract, package size, shipment size or the like of material to be charged for further processing or use and the input values Σ 1  and Σ 0  can be identified by a “look up” table resident within a controller  30  or entered by an operator according to desired target values. According to an aspect of the present invention, charging smaller increments from a continuous viscous feed material toward the end of a session (at Σ 1 ), permits charging of a precise total material for the session. With smaller increments, a session can be terminated within a small plus or minus material of the session target total quantity or amount (Σ 0 ). 
     Controller  30  has a set of instructions to store the input  403  values Σ 1  and Σ 0  representing the material set points for material to be charged from the MEA battery  411 . A start signal  405  activates  407  the MEA battery  411  comprising for example, 2, 3 or n number of material extracting apparatus  16 . Each of a battery  409  of sensors S 1 , S 2  . . . S n , senses a respective weight of each MEA of the battery  411 , including evacuator  22 , container  42  and contents. First, an initial weight is sensed of the evacuator  22  and a full container  42  prior to expressing any content. This initial value is input  413  to controller  30  and summed Σ i  and stored for all MEAs  16  of the battery  411 . Then as the viscous material process proceeds, each evacuator plunger  72  of each MEA  16  of battery  411  drives axially into each container  42  to express material from the container  42 . As material is expressed and cut to conveyor  18 , each sensor S 1 , S 2  . . . S n  senses a progressing combined weight of each material extracting apparatus  16 , container  42  and dwindling contained material and the combined weights are summed  415  to a sum weight Σ t . The sum weight Σ t  is subtracted  417  from Σ i  to provide a progressing amount of material Σ n  that represents material charged to the compounding system  14  by time or period n. 
     Then, progressing amount Σ n  is compared  419  with input values for target total material Σ 0  and amount of material Σ 1  that represents a first value that triggers the charging rate change. If the comparison  419  indicates that Σ n &lt;Σ 1 , then control of system  400  operation is cycled  421  and continued with continuing operation of the MEA  411  and input of values from the sensors S 1 , S 2  . . . S n . If the comparison  419  indicates that Σ n ≧Σ 1 , then control of the system is switched to control cycle  423  and MEA control module  425 . Control module  425  effects a next comparison of Σ n , this time with the target total material Σ 0  value. If Σ n &lt;Σ 0 , then processing continues  427  but the size of the cut increments is decreased; if Σ n ≧Σ 0 , then the process  400  is terminated  429 . 
     The following Example is illustrative and should not be construed as a limitation on the scope of the claims. 
     EXAMPLE 
     This EXAMPLE is a combined description of press (MEA) experiments at Schwerdtel US headquarters (New Jersey), ProSys Corporation (Missouri), and at GE Silicones Waterford, N.Y. Experiments on a shaftless screw conveyor were conducted at GE Silicones Waterford using Martin Sprocket equipment. 
     A viscous material feed system as schematically illustrated in the drawings included a Schwerdtel S 6-F drum press mounted to Vishay BLH floor scale that measured material flow according to loss of weight. The Schwerdtel S 6-F press included a hydraulic pressure driven cylinder and platen that drives a platen into a 55 gallon drum. 
     The feed system included a feed tube to receive material expressed from a drum by the press and a pneumatic solenoid operated cutting system that metered material from the feed tube to a 12″×24′ shaftless screw conveyor according to loss of weight sensed by the scale. The screw conveyor interfaced to a chute. The chute permitted material to fall via gravity directly to a Banbury mixer. Material remaining in the chute was cleared by a pneumatic pusher prior to each mix (GE design and fabrication). The system was controlled by operators at two (2) QuickPanel LM90 touch screens of a control system. 
     In operation, an operator first entered set point weight or amounts into a system controller. In this embodiment, one set point weight or amount represented a target batch of silicone gum to be charged to a Banbury mixer, which was part of a silicone gum compounding system. A pallet of four (4) fifty-five (55) gallon drums of silicone polymer (Viscosity Range 150,000 to 900,000 Poise) was placed on a drum carousel. The 55-gallon straight-sided steel drums were delivered by the carousel and one drum was loaded into the Schwerdtel S 6-F drum press using an Easy Lift Equipment Drum Hauler unit. The Schwerdtel S 6-F drum press was controlled by a GE Fanuc 90/30 PLC. Material was displaced, from the drum to the feed tube by the hydraulic Schwerdtel gum press. 
     The operator pressed a START OR RESTRT BATCH button of the controller to commence operation. The press doors were secured by hydraulically driven fasteners. Then, as the screw conveyor started turning, the hydraulically driven press platen commenced traveling down into the drum. As a platen traversed the drum, drum contents were squeezed upward into the feed tube. As the platen completed traversing the drum axis, all material was forced upward into the feed tube. As material exited the feed tube, a pneumatic solenoid operated cutting system diced the material into pieces that then felt into a 12″×24′ shaftless screw conveyor to charge to a Banbury mixer. 
     A batch of material flow from conveyor to the Banbury mixer was measured by loss of weight detected by the Vishay BLH load cells. A combined weight of presses, feed tubes, cutting mechanisms and material-containing drums was registered by the control system as a first weight. The control system monitored a charged weight of silicone gum to the Banbury by registering progressing weight as silicone gum was pressed from the drums and expelled through the feed tubes and cutting systems. The control system displayed a differential between the first weight and registered progressive weights that represented a charged silicone gum weight. The cutting mechanism rate was increased when charged silicone gum weight was within 15 pounds of the set point weight. The control system continued to sense the differential weight and terminated the batch operation when the differential weight registered within a ±2 pound range of the set point weight or amount. 
     The EXAMPLE illustrates control of material charge to a compounding system according to the invention. 
     The invention includes changes and alterations that fall within the purview of the following claims. The foregoing examples are merely illustrative of the invention, serving to illustrate only some of the features of the present invention. For example, the invention includes a controller with a set of instructions: to refer to a look-up data base to determine a set point weight or amount for a material to be charged to a compounding system; sensing an initial combined weight of a material extracting apparatus and a container with material; signaling commencement of the material extracting apparatus operation to evacuate the material from the container; sensing a progressing combined weight of the material extracting apparatus and the container with material; calculating a charged material weight according to a difference between the initial combined weight and the sensed progressing combined weight; and terminating the material extracting apparatus operation when a calculated charged material weight is within a specified range of the set point weight or amount. 
     The appended claims are intended to claim the invention as broadly as it has been conceived and the examples herein presented are illustrative of selected embodiments from a manifold of all possible embodiments. Accordingly it is Applicants&#39; intention that the appended claims are not to be limited by the choice of examples utilized to illustrate features of the present invention. 
     As used in the claims, the word “comprises” and its grammatical variants logically also subtend and include phrases of varying and differing extent such as for example, but not limited thereto, “consisting essentially of” and “consisting of.” 
     Where necessary, ranges have been supplied, those ranges are inclusive of all sub-ranges there between. Such ranges may be viewed as a Markush group or groups consisting of differing pairwise numerical limitations which group or groups is or are fully defined by its lower and upper bounds, increasing in a regular fashion numerically from lower bounds to upper bounds. It is to be expected that variations in these ranges will suggest themselves to a practitioner having ordinary skill in the art and where not already dedicated to the public, those variations should where possible be construed to be covered by the appended claims. 
     It is also anticipated that advances in science and technology will make equivalents and substitutions possible that are not now contemplated by reason of the imprecision of language and these variations should also be construed where possible to be covered by the appended claims. 
     All United States patents (and patent applications) referenced herein are herewith and hereby specifically incorporated by reference in their entirely as though set forth in full. 
     The invention includes changes and alterations that fall within the purview of the following claims.