Abstract:
A viscous material container evacuator comprises a chamber to hold a container and a plunger axially and slidably accommodated within the chamber to express material from the container; and at least one hinged closure that closes to define the chamber and to securely enclose the container; and at least one motor activated fastener that secures the closure around the container. A method to secure a closure of a viscous material container evacuator, comprises activating a motor drive shaft to drive a connected threaded shaft into a complimentary threaded channel of a clamp block that comprises an opposing nub wall; and driving the threaded shaft to impose upon a first lug of an evacuator and to foreshorten a distance between a head of the threaded shaft and the opposing nub to impose the nub against a second lug of a closure to secure the lugs together to secure the container.

Description:
This application is a continuation in part of Stanton et al., Viscous Material Feed System and Method, Ser. No. 11/532,334, filed 15 Sep. 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a fastener for a container evacuator and a method, in particular for a drum evacuator for pressing silicone gum or other viscous material from a container to a continuous compounding system. 
     In a compounding system, a viscous material is fed to a processing line where feed is mixed and additives are injected in proportions to produce a customized product. The feed material for these processes can be delivered in various containers to the compounding site. When delivered, the material must be removed from the container for processing. For example, a compounding system can require emptying material such as silicone gum from drums or similar containers. However, the feed material may be very viscous and resistant to flow and hence, resistant to removal from the delivery container. 
     Some emptying processes use a plunger to drive through a container content to express the content for further processing. A considerable amount of pressure is needed in these processes to express a viscous material such as a silicone gum. The high expressing force exposes the materials container to very high mechanical stress. For reasons of weight and expense, the containers are usually designed with very thin walls and a structure that is just sufficient to avoid damage to the container during transport. The container is not designed to withstand stress imposed during the emptying operation and the high pressure developed during an emptying operation can easily burst a container structure. 
     Reinforcing split metal sleeves or half-shells can be placed around a container during an emptying operation. However, the mounting and closing off of the sleeves and half-shells can be very complicated operations, requiring considerable manual labor. Another disadvantage is that the sleeves or half-shells must be adapted in an exact manner to the outside container dimensions thus sometimes requiring an inventory of sleeves or half-shells to accommodate various sized containers. 
     Accordingly, there is a need to facilitate the removal of a viscous feed material from a container, particularly removal of a viscous feed material such a viscous silicone from a delivery container such as a drum. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention provides an improved viscous material container evacuator and method to remove viscous material from a delivery container to a processing system. The invention is describable as a viscous material container evacuator, comprising: a chamber to hold a container and a plunger axially and slidably accommodated within the chamber to express material from the container; at least one hinged closure that closes to define the chamber and to securely enclose the container; and at least one motor activated fastener that secures the closure around the container. 
     In an embodiment, the invention is a method to secure a closure of a viscous material container evacuator, comprising: activating a motor drive shaft to drive a connected threaded shaft into a complimentary threaded channel of a clamp block that comprises an opposing nub wall; and driving the threaded shaft to impose the nub upon a first lug of an evacuator and to foreshorten a distance between a head of the threaded shaft and the opposing nub to impose the nub against a second lug of a closure to secure the lugs together to secure the container. 
     Another embodiment of the invention is viscous material processing system, comprising: a viscous material feed system comprising: a viscous material container evacuator comprising a chamber to hold a container and a plunger axially and slidably accommodated within the chamber to express material from a container held within the evacuator chamber and enclosable by hinged closures that define the chamber, the closures securable by at least one motor activated fastener that secures the closure around the container; and a viscous material compounding system that receives material expressed from the feed system. 
     Another embodiment is a viscous material feed system, comprising: a container evacuator comprising a chamber to hold a container and a plunger axially and slidably accommodated within the chamber to express material from the container held within the evacuator chamber; and at least one hinged closure that closes to define the chamber and to securely enclose the container; and at least one motor activated fastener that secures the closure around the container; a feed tube that receives material expressed from a container by the container evacuator; and a cutting apparatus that meters material from the feed tube to a processing system. 
     And, another embodiment is a viscous material feed method, comprising: placing a viscous silicone gum containing drum into a material extracting apparatus; securing closure of the material extracting apparatus around the drum by activating a motor drive shaft to drive a connected threaded shaft into a complimentary threaded channel of a clamp block that comprises an opposing nub wall; and driving the threaded shaft to impose upon a first lug of closure of the apparatus and to foreshorten a distance between a head of the threaded shaft and the opposing nub to impose the nub against a second lug of a closure of the apparatus to secure the lugs together; and evacuating viscous material from the drum by driving a plunger through the drum to express the silicone gum a viscous material compounding process. 
     Another embodiment is a viscous material container evacuator, comprising: a chamber to hold a container and a plunger axially and slidably accommodated within the chamber to express material from the container; at least one hinged closure that closes to define the chamber and to securely enclose the container; at least one motor activated fastener that secures the closure around the container; and a hydraulic system that powers the motor, comprising a hydraulic pressure supply, and a relief cartridge that controls the pressure supply to activate the motor by diverting pressure supply from the motor when a set point pressure is attained. 
     And, another embodiment is a method of controlling a battery of hydraulically operated fasteners to a viscous material container evacuator, comprising: setting a set point pressure for each fastener of the battery; supplying an activating hydraulic fluid pressure to each fastener; and diverting the applied pressure from each fastener as the set point for that fastener is attained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         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; 
         FIG. 7  is a perspective view of a hinged closure with closure door fasteners; 
         FIG. 8  is an exploded view of a fastener and hydraulic motor; 
         FIG. 9  is an exploded view of a misalignment coupling; 
         FIG. 10  is a schematic perspective cut away view of an open fastener; 
         FIG. 11  and  FIG. 12  are cut away views of a closed fastener and a fastener in an overrun condition; 
         FIG. 13  is a partially cut away elevation view of a hydraulic motor; and 
         FIG. 14  is a diagram of fastener hydraulics. 
     
    
    
     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 of a quantity of the material from a larger quantity. Also, it is costly and wasteful to have to clean processing equipment on a frequent basis when the fluid material sticks to a cutting tool or instrument; also, it is costly, and disadvantageous when an incorrect amount of material is used in a downstream process. 
     A material evacuation process exerts substantial force against a container wall to threaten rupture of the container. Both the evacuator and any fastener to the evacuator closures must be robustly capable of securing closure against the substantial force. The invention provides a secure closure with a fastener that can with stand high forces exerted on a container wall during material evacuation. The fastener can include a hydraulic motor that drives a lock mechanism that includes a threaded shaft and a clamp block with a nub and a threaded channel that accepts the threaded shaft. The motor drives the threaded shaft to foreshorten the distance between a first closure lug and a lug on a second closure or on the evacuator wall to enclose the container for evacuation. Also, an embodiment of the fastener addresses problems of misalignment between the drive shaft and threaded shaft that arise on account of part tolerance divergence and operational wear. 
     In this application, the term “play” means movement or space for movement, as of mechanical parts. A degree of play means a tolerance that permits relative movement between parts without disengagement. A reference to “back” means left on a drawing or drawings and a reference to “forward” means right on the drawing or drawings. 
     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. 
     A preferred invention 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 material processing system  10  showing an integrated feed system  12  and compounding system  14 . The feed system  12  includes a material extracting apparatus (MEA)  16 , conveyor  18  and chute  20 .  FIG. 4  and  FIG. 5  are elevation views of the 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 schematic side view of compounding system  14 . 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 from a pallet are dumped into totes and the totes (approx. 80 pounds each) are dumped into a Banbury mixer. However, manually maneuvering drums from pallets can cause back and shoulder strains and injuries. 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 container can be any material holding enclosure, the drawings embodiment is a feed system including a method of evacuating a silicone gum-containing drum. 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, Delaware 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  42 , 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 in measured aliquots by the MEA  16  into the conveyor  18 . In the drawings embodiment, the 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. 4  and  FIG. 5 , the container evacuator  22  is a press that comprises a substantially cylindrical chamber  50  with hinged closures  52  and  54  for securing a drum  42  removably within the chamber  50 . The chamber  50  and hinged closures  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  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 closures  52  and  54  are manually unlatched by activating fasteners  110  and opening closures  52  and  54 . The drum hauler  44  is used to load a first drum  42  into the press cavity  60 . The press closures  52  and  54  take pressure of the hydraulic system from a drum  42  that may be thin-walled. The closures  52  and  54  are secured by a plurality of fasteners  110 , which are described in detail with reference to  FIGS. 7 to 10 . 
       FIG. 7  is a perspective view of hinged closures  52  and  54  secured with fasteners  110 . The fasteners  110  serve to clamp and align the hinged closures  52  and  54  as described hereinafter.  FIG. 8  is an exploded perspective view of one fastener  110  includes hydraulic motor  112  with drive shaft  114 . From left back to front forward, fastener  110  comprises misalignment coupling  116 , restart spring pin  118 , restart spring  119 , drive tube  120 , threaded shaft  122 , drive housing  124 , snap pin  126  and clamp block  132 . Threaded shaft  122  has a splined reduced diameter back section  158 , a threaded middle section  160  and a forward reduced diameter plane section  162 . A back face  164  is directed toward the drive shaft  114  and a forward face  166  is directed toward a threaded channel  168  of clamp block  132 .  FIG. 10  and  FIG. 11  show lugs  128  and  130  as respective sections of hinged closures  52  and  54 . 
     Misalignment coupling  116  serves to transmit mechanical power from one rotating shaft to another where the shafts are not in exact alignment. In  FIGS. 9 to 11 , the misalignment coupling is shown transmitting mechanical power from drive shaft  114  to threaded shaft  122 . Misalignment coupling  116  is a three section part including back couple half  134  and forward couple half  136  and coupler section  138 . Each couple half  134  and  136  has a configured interior that forms a continuous passageway  140  through coupler section  138 . Coupler section  138  has back keys  142  and forward keys  144  that nest respectively into complementary keyways  146  of back couple half  134  and keyways  148  of forward couple half  136 . Connector  134  has retaining groove  150  and forward couple half  136  has retaining groove  152  and the couple halves  134  and  136  are retained by respective retaining rings  154  and  156 . The keyways  146  and  148  with inserted keys  142  and  144  and retaining rings  154  and  156  loosely connect each couple half  134  and  136  with the coupler section  138 . 
     Back couple half  134  interior passageway  140  has an inner cylindrical splined surface  170  adapted to receive a complementary splined surface  172  of drive shaft  114  and forward couple half  136  has a splined surface  174  adapted to receive the complementary splined surface of reduced diameter back section  158  of threaded shaft  122 . The  172 ,  158  splined surfaces are configured and oriented to nestle within respective spline surfaces  170 ,  174  in an interdigitated manner. The term interdigitated means that the splines are interlaced as fingers of two hands can be joined in parallel. 
     Coupler section  138  interior passageway  140  portion has a smooth wall and this portion of the passageway  140  has a larger diameter than back couple half or forward couple half diameters defined by grooves of the splined surfaces  170  and  174 . The coupler section  138  connects the halves  134 ,  136  so that the spline configurations of the halves  134 ,  136  are misaligned to trap the drive shaft  114  and threaded shaft  122  to one another. The keys  142  and  144  are held by rings  154  and  156  with some degree of axial play and are placed  900  out of phase to one another to provide a slackened tolerance to both axial and angular misalignment between drive shaft  114  and threaded shaft  122 . The misalignment coupling  116  configuration transmits drive shaft torque while accommodating axial and angular misalignment. 
       FIG. 10  is a schematic cut away view of an open fastener;  FIG. 11  is a cut away side view of a closed fastener; and  FIG. 12  is a schematic cut away side view of a fastener in an overrun condition. With reference to  FIGS. 5 through 12 , a method of securing the hinged closures  52  and  54  comprises activating hydraulic motor  112  to cause drive shaft  114  to drive connected threaded shaft  122  into complimentary threaded channel  168  of clamp block  132 . Clamp block  132  is a bracket shaped piece with threaded channel  168  at a back bracket end  180  and a biasing structure shown as nub structure  184  with nub  186  at a forward bracket  182  end. In operation, the threaded shaft  122  threads through threaded channel  168  and a forward face  166  of the shaft  122  imposes upon a first lug  128  of the MEA  16 . Clamp block  132  is connected with drive housing  124  via mounting pin  188  and snap rings  190  through drive housing  124  opening  192  and aligned slot  194  of clamp block  132  (and securing lug  128  through its hole  198 ). And, drive housing  124  is connected to the motor  122  through drive tube  120  by means of fasteners  196  ( FIG. 8 ). So as the motor  112  advances the threaded shaft  122  the shaft  122  in turn draws clamp block  132  (via the motor  112  to drive tube  120  drive housing  124  to clamp block  132  connection) to foreshorten a distance between the nub  186  until the nub  186  imposes against lug  130  of closure  54 . The nub  186  is tightened by action of the threaded shaft  122  to bind the lugs  128 ,  130  to form a powerful hydraulic driven closure of the MEA  16  around a drum  42  within the MEA chamber  50 . 
     An overrun backoff mechanism is another embodiment illustrated in  FIGS. 10 through 12 . Restart pin  118  and a restart spring  119  are shown in  FIGS. 8 and 10  through  12 .  FIG. 10  illustrates the open fastener  110  showing the threaded shaft  122  substantially but not completely unthreaded from threaded channel  168 . The restart pin  118  and restart spring  119  are imposed into a passage  202  of the threaded shaft  122  longitudinal axis. The  FIG. 10  shows the restart pin  118  biased by the drive shaft  114  against the threaded shaft  122  but with travel remaining within the passage  202 .  FIG. 11  shows the lock fully closed with the restart pin  118  advanced against the fully compressed restart spring  119  imposing against the threaded shaft  122  passage  118  end. The restart pin  118  pushes (biases) on the threaded shaft  122  to cause it to fully extend and to reengage the clamp block. Then in an overrun condition as shown in  FIG. 12 , the lead screw unthreads itself from the clamp block . . . . 
     Another embodiment of the invention relates to hydraulic control of the fastener  110 . In  FIG. 4  and  FIG. 5 , each hydraulic motor  112  has a relief cartridge  210  with hydraulic lines (not shown) connected to a hydraulic source (not shown). An exemplary hydraulic motor  112  with relief cartridge  210  and hydraulic line ports  212  and  214  is illustrated in  FIG. 13 . 
       FIG. 14  is a diagram of a hydraulic system  216  that includes matching cartridges  218 ,  220  and  222  that are associated with motors  224 ,  226  and  228 . This configuration correlates to the three cartridges  210  and motors  112  of  FIG. 4  and  FIG. 5 .  FIG. 14  shows a four way, three position tandem spool valve  230 . In an open position, hydraulic fluid flows from port P to port A and port B to port T. This results in hydraulic fluid flow from port A to port B of each motor  112 . In an exemplary operation, output torque of motor  224  correlates to a differential pressure across the motor. When the differential reaches a set point, relief cartridge  218  terminates motor  224  rotation by diverting the hydraulic fluid flow through the other relief cartridges  220  and  222 . Similarly, differential is sensed and flow through each respective cartridges  220  and  22  and associated motors  226  and  228  is terminated when the set point is reached. When a set point for all motors  224 ,  226  and  228  is reached, the three corresponding fasteners should be in an open position to permit access to the container evacuator  22 . In an embodiment, the set point is stored and pressure is evaluated with a controller that may be a PLC and pressure transmitter combination (not shown). 
     In other terms, as hydraulic fluid flows into port B and out of port A of hydraulic motor  112  causing Lead Screw  122  to rotate unscrewing itself from Clamp Block  132 . This causes clamp Block  132  to extend. Once Clamp Block  132  has extended to the point that Clamp Block  132  comes into contact with Lug  128 , as illustrated in  FIG. 10 , Clamp Block  132  is at its end of travel and can extend no further ( FIG. 10 ). If the hydraulic motor continues to run Lead Screw  122  will continue unscrewing itself from Clamp Block  132 . With no travel left for the Clamp Block  132 , Lead Screw  122  will travel toward hydraulic motor  112 , compressing Restart Spring  119  between Restart Pin  118  and the bottom of hole bored in center of Lead screw  122 . The threads on lead screw  122  will eventually disengage from Clamp Block  132  ( FIG. 12 ). With the threads of the Lead Screw  122  disengaged from Clamp Block  132 , continued rotation of Lead screw  122  will cause no further travel in either Lead screw  122  or Clamp Block  132 . 
     In an overrun situation, hydraulic fluid flows into port A and out of port B of hydraulic motor  112  causing rotation of Lead Screw  122  in its tightening direction. Restart Spring  119  presses on Lead screw  122  pushing its threads into the Threaded bore of Clamp Block  132  causing the threads to reengage. Once the threads of Clamp Block  132  and Lead Screw  122  have reengaged Lead Screw  122  will travel toward Lug  128 . Lead Screw  122  will come in contact with Lug  128  ( FIG. 10 ), at this point Clamp Block  132  will begin to retract. Once the Nipple  134  comes into contact with Lug  130  the torque required to rotate the Lead Screw  122  will increase. Because the pressure differential from port A and B of Hydraulic motor  112  correlates to its output torque, the pressure drop across ports A to B of hydraulic motor  112  increases. Maximum torque is set by means of limiting the maximum hydraulic pressure drop from port A to B of hydraulic motor. 
     In a fastener unlocking cycle, a solenoid of the spool valve  230  directs fluid flow from port P to port B and from port A to port T resulting in hydraulic flow from port B to port A in each motor  224 ,  226  and  228 . Flow from port B to port A actives each motor  224 ,  226  and  228  to open each fastener  110 . When an open situation is determined by PLC timing, the PLC returns the valve  230  to neutral. In an event that a motor fails to operate when hydraulically activated, a relief valve  232  prevents pressure from increasing above a “burst pressure.” 
     Each MEA  16  includes the container evacuator  22 , feed tube  24  and cutting apparatus  26  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  to communicate with the press cavity  60 . The platen  56  is driven by hydraulic plunger  72 . When a batch is set up by loading each chamber  50  of the feed system  12  battery, an operator can initiate a system cycle by controller  30  touch screen located at a work station. The controller  30  can be a microprocessor or computer or the like for controlling the MEA  16  as hereinafter described. 
     The operator can commence system operation at controller  30 . When a cycle is activated by an operator, a plunger  72  of each container evacuator  22  of the battery shown in  FIG. 1  is activated via control lines  74  ( FIG. 4  and  FIG. 5 ). 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 small pieces 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 of the feed tube. For example, Brandl, U.S. Pat. No. 5,797,516, incorporated hereto in its entirety discloses a cutting head formed by a knife that is detachably mounted in an axial direction and radial and tangential to the axial direction. The cutting head is situated relative to a feed tube about a common central longitudinal axis. 
     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  and  86 . 
     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 charged 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 controls 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 in 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 . When 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”) to the compounding system  14 , the controller can signal the cutting apparatus  26  via lines  84  to increase cut frequently to produce smaller “diced” pieces. The smaller diced pieces at approach to set point 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 of the hinged closures  52  and  56  open and a controller  30  Run Screen displays “NEW DRUM.” A beacon light mounted on the container evacuator  22  turns yellow, indicating the drum  42  is ready to be changed. The chamber  50  hinged closures  52  and  56  open the hydraulic unit motor terminates. The door fasteners are opened and the empty drum is removed, typically with the drum hauler. The press is reloaded with a drum the process repeated. 
     As material is charged from the presses to the screw conveyor, 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 press makes its last cut. We have determined this time to be adequate to clear all material from the conveyor. 
     Conveyor  18  transports and drops the silicone gum to chute  20 , which drops the material into a material compounding system  14 . In one silicone compounding process, a heat cured rubber (HCR) composition can be produced by kneading a high-viscosity polydiorganosiloxane, an inorganic filler and additives by means of a batch kneading machine such as the high intensity Banbury mixer  32  or a low intensity double arm dough mixer. In this process, silicone gum, inorganic filler, treating agents and additives are batch mixed until desired properties are obtained. In Kasahara et al., U.S. Pat. No. 5,198,171, a preconcentrate of silicone gum, inorganic filler and treating agents is formed by a high speed mechanical shearing mixer. The resulting premix is further compounded in a same-direction double screw extruder. A premix is formed in a first step wherein a silicone gum having a viscosity at 25° C. of 1×10 5  cP or more, an inorganic filler and a treating agent are mixed in a high speed mechanical shearing machine to provide a flowable particulate mixture in which each ingredient is present in a substantially uniform, finely dispersed state. The flowable particulate mixture is then fed at a constant feed rate into a kneading and extruding machine that has two screws rotating in the same direction. 
     As the material exits from the end of the conveyor, it falls into a chute. It tumbles down the chute directly into the mixing chamber of a Banbury mixer where feed is mixed with filler and additives. In the  FIGS. 1 ,  2  and  3  embodiment, the silicone gum drops through chute  20  to compounding system  14 , which includes mixer  32  such as a Banbury, roll mill  34 , conveyor belt  36  and compounder  38 . The material dropped from chute  20  may be a feed of silicone gums of varying physical properties such as varying viscosity. 
     In the mixer  32  such as a Bepex Turbolizer, 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  46  of roll mill  34  where the material is rolled into a strip form. After a drop, a programmed logic controller (PLC) verifies that the mixer drop door has opened, then reclosed and is ready for feed. For any residual material that hangs in the chute, the “pusher” is programmed to sweep a few seconds after the conveyor stops. This serves to scrape down the chute, and ensure all material gets into the mixer 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 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 feed system and method of the invention can be used in conjunction with a process to compound a silicone rubber into a base for sealing compounds with additives such as pigments dosed to the rubber in appropriate quantities and mixed in large mixers or extruders.  FIG. 1  illustrates an exemplary process wherein a filler such as fumed silica is continuously treated and compounded with a silicone polymer such as a vinyl-terminated polydimethylsiloxane. 
     A heat cured rubber (HCR) comprises a high viscosity silicone polymer, an inorganic filler and various additives that aid processing or impart desired final properties to the composition. A vulcanizing agent or catalyst can be added and the composition heat cured to fabricate silicone rubber moldings such as gaskets, medical tubing and computer keypads. An HCR composition can be produced by kneading a high-viscosity polydiorganosiloxane, the inorganic filler and additives by means of a batch kneading machine such as a high intensity Banbury mixer or a low intensity double arm dough mixer. In this process, polydiorganosiloxane, inorganic filler, treating agents and additives are batch mixed until desired properties are obtained. In Kasahara et al., U.S. Pat. No. 5,198,171, a preconcentrate of polydiorganosiloxane, inorganic filler and treating agents is formed by a high speed mechanical shearing mixer. The resulting premix is further compounded in a same-direction double screw extruder. The premix is formed in a first step wherein a diorganopolysiloxane having a viscosity at 25° C. of 1×10 5  cP or more, an inorganic filler and a treating agent are mixed in a high speed mechanical shearing machine to provide a flowable particulate mixture in which each ingredient is present in a substantially uniform, finely dispersed state. The flowable particulate mixture is then fed at a constant feed rate into a kneading and extruding machine that has two screws rotating in the same direction. 
     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 experiments at Schwerdtel US headquarters (New Jersey), ProSys Corporation (Missouri), and at GE Silicones Waterford, N.Y. Experiments on the 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 the 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. 
     In operation, an operator first entered set points into a system controller. One set point 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 polymer (Viscosity Range 150,000 to 900,000 Poise) was placed on the 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 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 fell 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. 
     A system operator observed the differential weight and terminated the batch operation when the differential weight registered within a ±2 pound range of the set point, the pneumatic solenoid operated cutting system rate was increased to dice smaller aliquots of exiting material. The batch feed operation was terminated by the operator when the control system registered a charged silicone gum weight with 2 pounds of the set point. 
     The EXAMPLE illustrates control of material charge to a compounding system according to a feed system of 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 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. 
     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 entirety as though set forth in full. 
     The invention includes changes and alterations that fall within the purview of the following claims.