Abstract:
A viscous material feed system, comprises a feed tube that receives material expressed from a container; and a container evacuator comprising a chamber to hold a container to express material from the container to the feed tube and a plunger comprising a platen axially and slidably accommodated within the chamber, the platen comprising an O-ring fitted against a platen driving face; a full ring with tabs extending to secure the O-ring to the platen driving face with a circumferential surface exposed to the chamber and a vacuum breaker valve to the chamber that seals the platen face when in contact with container material and retains residual material adhering to the platen face when the valve is activated at a termination of a driving cycle of the platen through a container content.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a viscous material feed system with a platen and method, in particular for a viscous material processing system. 
         [0002]    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. Feed material for these processes can be delivered to processing sites in various containers. When delivered, the material must be removed from the container for processing. For example, a processing 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. 
         [0003]    Some container emptying processes use a plunger to drive through the container to empty its content. In these processes, a flat forward platen of the plunger imposes upon the material to drive it from the container for further processing. However, forcibly driving material from a container requires that both container ends be open. The open ends can adversely affect container integrity. Forcibly emptying the open container can result in rupture and loss of material. Other less robust emptying methods avoid container collapse but fail to completely empty a container. There is a need for a device and method to remove viscous material from a container to empty all the material without collapsing the container. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    The invention provides a system and method to express substantially all material from a container to a viscous material processing system without collapsing the container. 
         [0005]    In an embodiment, the invention is a viscous material feed system, comprising: a feed tube that receives material expressed from a container; and a container evacuator comprising a chamber to hold a container to express material from the container to the feed tube and a plunger comprising a platen axially and slidably accommodated within the chamber, the platen comprising an O-ring fitted against a platen driving face; a full ring with tabs extending to secure the O-ring to the platen driving face with a circumferential surface exposed to the chamber and a vacuum breaker valve to the chamber that seals the platen face when in contact with container material and retains residual material adhering to the platen face when the valve is activated at a termination of a driving cycle of the platen through a container content. 
         [0006]    In another embodiment, the invention is a viscous material feed method, comprising: driving a platen face against a surface of a viscous material held in a container; creating a vacuum between the platen face and viscous material surface to adhere residual material from the container to the platen face; differentially breaking the vacuum at a circumference of the residual adhered material to retain the residual material adhered to the platen face to permit withdrawal of the residual material from the container along with the platen face. 
         [0007]    In another embodiment, the invention is a viscous material processing system, comprising: a container evacuator comprising a platen comprising at least two ports through the platen, the ports located at balancing equal circumferential spacings from a central activating piston to the platen; and a compounding system that receives viscous material expressed from a container by the container evacuator. 
         [0008]    In another embodiment, the invention is a container evacuator, comprising: a chamber to hold a container to express material from the container to a feed tube; and a plunger comprising a platen axially and slidably accommodated within the chamber, the platen comprising an O-ring fitted against a platen driving face; a full ring with tabs extending to secure the O-ring to the platen driving face with a circumferential surface exposed to the chamber and a vacuum breaker valve to the chamber that seals the platen face when in contact with container material and retains residual material adhering to the platen face when the valve is activated at a termination of a driving cycle of the platen through a container content. 
         [0009]    In still another embodiment, the invention is a viscous material feed system, comprising: a feed tube that receives material expressed form a container; and a container evacuator comprising a platen comprising at least two parts through the platen, the ports located at balancing equal circumferential spacings from a central activating piston to the platen, wherein the piston drives the platen through the container to express material through the ports to the feed tube. 
         [0010]    In another embodiment, the invention is a viscous material processing system, comprising: a container evacuator comprising a chamber to hold a container to express material from the container to the feed tube and a plunger comprising a paten axially and slidably accommodated within the chamber, the platen comprising an O-ring fitted against a platen driving face; a full ring with tabs extending to secure the O-ring to the platen driving face with a circumferential surface exposed to the chamber and a vacuum breaker valve to the chamber that seals the platen face when in contact with container material and retains residual material adhering to the platen face when the valve is activated at a termination of a driving cycle of the platen through a container content; a controller that drives the container evacuator; a feed tube that receives material expressed from a container by the container evacuator according to the controller; and a cutter that severs material from the feed tube to meter the material to a processor according to the controller. 
         [0011]    In still 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 container evacuator comprising a chamber to hold a container to express silicone gum from the container to the feed tube and a plunger comprising a platen axially and slidably accommodated within the chamber, the platen comprising an O-ring fitted against a platen driving face; a full ring with tabs extending to secure the O-ring to the platen driving face with a circumferential surface exposed to the chamber and a vacuum breaker valve to the chamber that seals the platen face when in contact with container silicone gum and retains residual silicone gum adhering to the platen when the valve is activated at a termination of a driving cycle of the platen through a container content. 
         [0012]    In another embodiment, the invention is a viscous material feed method, comprising: driving a platen face against a surface of a viscous material held in a container to express the material from the container through symmetrically located ports through the platen face to a feed tube; and cutting material from the feed tube to a viscous material compounding system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1 ,  FIG. 2  and  FIG. 3  are schematic representations of a material processing system; 
           [0014]      FIG. 4  and  FIG. 5  are perspective views of a drum press; 
           [0015]      FIG. 6  is a cut away view of a section of a drum press; and 
           [0016]      FIG. 7  is a perspective,  FIG. 8  is a side elevation and  FIG. 9  is a bottom view of a platen. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0017]    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. 
         [0018]    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. A silicone gum can have a viscosity range between 150,000-900,000 poise at 25° C. 
         [0019]    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. 
         [0020]    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. 
         [0021]    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 or for removing material from a container. 
         [0022]    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. 
         [0023]    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 battery of 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 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 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 . 
         [0024]    The MEA  16  serves to express the viscous material from a container to the compounding system  14 . By “express” is meant to squeeze, force or press out the viscous material from the container. 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. The drawings embodiment illustrates a feed system including a method of evacuating a silicone gum-containing drum. A suitable drum  42  in the embodiment, has fully 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. 
         [0025]    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 modified 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 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 . 
         [0026]    As illustrated in  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. Platen face  316  is 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 . 
         [0027]    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. 
         [0028]    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 . 
         [0029]      FIG. 7  is a perspective view of the plunger  72  that provides a mechanism to express viscous material from a drum according to a preferred embodiment of the invention. A preferred plunger  72  shown in  FIG. 7 ,  FIG. 8  and  FIG. 9 , includes disc-shaped platen  56  drive by activating piston  312 . O-ring  314  fits to the platen  56  face  316  to seal platen  56  outer circumference to inner wall  336  of drum  42 . The O-ring  314  is held in place by a full ring  320  that is affixed to platen face  316  to partially encompass the O-ring  314  but with exposed portion that extends circumferentially beyond the outer circumference of both platen  56  and the full ring  320 . 
         [0030]    Shown are two ports  322  through the full ring  320  and platen  56  to communicate with respective conduit tines  324  that converge to feed tube  24  as shown in  FIG. 6 . The ring  320  has tabs  334  welded to full ring  320  to extend across the exposed outer circumference surface of the O-ring  314 .  FIG. 11  is an elevation that shows abutment of beveled circumference edge surface  328  of the full ring  320  to a corresponding sloped edge surface  330  of the O-ring  314 . 
         [0031]    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  74 . 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. 
         [0032]    As platen  56  is driven into drum  42 , displaced air is exhausted through vacuum breaker  332 . When the platen face  316  contacts drum material, the vacuum breaker valve  332  closes to seal the platen face  316  and the O-ring  324  seals the side of the platen  316  to the inside wall  336  of drum  42  (shown in  FIG. 8 ). 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 connecting ports  322  of the feed tube  24 . As the platen  56  completes traversing the drum axis, material is forced upward into the feed tube  24  to be eventually expelled from the feed tube discharge port  70 . Then as the platen  56  is raised from the drum  42  bottom, a vacuum is created below the platen  56  and the O-ring  314  is caused to slightly sag between tabs  334 . This results in residual viscous material from the drum  42  adhering to the platen face  313  to complete the drum  42  evacuation as the platen is withdrawn at the termination of a driving cycle. 
         [0033]    While applicant does not intend to be bound by any particular mechanism, it is believed that substantially all material is emptied from the drum  42  as the platen  56  is withdrawn because vacuum breaks first at the edge of the platen, rather than the vacuum breaker/vent valve. The edge vacuum break is caused by the O-ring  314  sag and its bevel/slope  328 / 330  interface with full ring  320 . Because the vacuum breaks first at the edge of the platen air flows between the drum and product allowing the product to stick to the platen leaving no material in the drum. Any material left at the bottom of the drum  42  adheres to the plate face  316  to be drawn up for easy removal by an operator. 
         [0034]    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 of the feed tube. 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 container  30  via lines  84  and  86  ( FIG. 1 ). 
         [0035]    The controller  30  of  FIG. 1  illustrates an embodiment of the invention. The controller  30  of  FIG. 1  can be a microprocessor, computer, data processing device, semiconductor chip or the like. Controller  30  is respectively 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 second total weight. 
         [0036]    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 form 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 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. 
         [0037]    As the drum  42  evacuation process is completed, door fasteners of the hinged enclosures  52  and  56  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. 
         [0038]    As material is charged from the MEAs  16  tote 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 . 
         [0039]    Conveyor  18  transports and drops the cut viscous material to chute  20  to compounding system  14 , which includes mixer  32  such as 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  46  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. 
         [0040]    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. 
         [0041]    The following Example is illustrative and should not be construed as a limitation on the scope of the claims. 
       EXAMPLE 
       [0042]    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. 
         [0043]    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. 
         [0044]    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. 
         [0045]    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. 
         [0046]    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. When the platen completed traversing the drum axis, the operation was terminated and the platen was withdrawn. As the platen was withdrawn, a vacuum between the bottom of the platen and adhering material was interrupted first selectively at the platen face circumference. The selective interruption caused substantially all remaining viscous material from the drum to remain adhered to the platen face to be removed and fed into the feed tube by a worker. 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. 
         [0047]    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. 
         [0048]    The EXAMPLE illustrates control of material charge to a compounding system according to the invention. 
         [0049]    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. 
         [0050]    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. 
         [0051]    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.” 
         [0052]    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. 
         [0053]    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. 
         [0054]    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. 
         [0055]    The invention includes changes and alterations that fall within the purview of the following claims.