WO2004050338A2

WO2004050338A2 - Platen press

Info

Publication number: WO2004050338A2
Application number: PCT/US2003/038309
Authority: WO
Inventors: Douglas Bryan; Charles Kosa; Clinton Spangler; Bryon Sanford; Joseph Zab
Original assignee: Coe Manufacturing Co
Current assignee: Coe Manufacturing Co
Priority date: 2002-12-03
Filing date: 2003-12-03
Publication date: 2004-06-17
Anticipated expiration: 2005-06-03
Also published as: AU2003297619A1; AU2003297619A8; WO2004050338A3

Abstract

A platen (14) for supporting material to be processed in a platen press including a plate portion (100) defining substantially planar upper and lower surfaces. A fluid circuit in the plate portion supports the flow of heated fluid through the plate portion. A plurality of collection bores (140) are formed in the plate portion for collecting byproducts generated during a processing cycle. A plurality of vent passages (150) extend from the lower planar surface of the platen to an associated collection bore. A side bar (102), attached to the plate portion, defines at least in part a collection chamber (160) for receiving the byproducts collected by the collection bores. The collection chamber is adapted to discharge the products to a discharge conduit (164). The communication of the collection chamber with the discharge conduit is controlled by an on/off control valve. In operation, the control valve is opened at the conclusion of a processing cycle, but prior to opening the press so that the process byproducts can be discharged to the discharge conduit prior to press opening. Prior art platens can be retrofitted with features of the invention by removing a side bar from the platen in order to expose a side edge (106b) of a plate portion (100). A plurality of collection bores (140) and associated vent passages (150) are machined into the platen. A recess or slot (160) is formed in the side bar, such that when reattached to the plate portion, the recess is placed in fluid communication with the collection bores. The byproducts collected are ultimately conveyed to the discharge conduit.

Description

PLATEN PRESS

Technical Field

The present invention relates generally to platen presses and, in particular, to an improved platen for use in a platen press.

Background Art

Presses having multiple moving platens are commonly used to process sheet material, such as rubber and wood products. In the type of platen press to which this invention pertains, the platens are heated during the processing cycle. The source of heat may be a heated fluid, such as steam or hot oil, that is conveyed through the platen by means of passages formed in the platen itself. An example of a platen press which may include a heated platen is disclosed in U.S. Patent No. 5,634,398, which is owned by the present assignee and which is hereby incorporated by reference.

During processing of materials by platen presses, it is common for the material to release water vapor or other gases. In conventional platen presses, these gases may be suddenly released as the platen press opens and the platens separate. In prior art constructions, the separation of the platens is carefully controlled to deal with the escaping gas. Generally, the platens are opened very slowly so a sudden release of water vapor or gas is avoided which may otherwise disturb the processed material. Cycle times for processing material can be substantially increased due to the slow opening of the press at the conclusion of the processing cycle.

Disclosure of Invention

The present invention provides a new and improved platen for use in a platen press that includes structure for receiving water vapor or other gases during the processing cycle. The present invention also provides a method for retrofitting existing platens to incorporate features of the invention. In accordance with the preferred embodiment of the invention, the platen includes collection bores formed in the platen which are connected to vent passages which extend from at least one surface of the platen and terminate in the bores. During a processing cycle, any water vapor or other gas formed in the material can travel into the collection bores via the vent passages and thus be conveyed out of the press during the actual processing cycle. As a result, much of the water vapor and gas created during the processing of the material is discharged prior to opening of the press.

In the preferred and illustrated embodiment, the collection bores are formed in a plate portion of the platen. In the exemplary embodiment, vent passages extend from an associated collection bore to a lower planar surface defined by the platen. A side bar is attached to a side edge of the plate portion and defines, at least in part, structure that serves as a collection chamber or manifold that is in fluid communication with the collection bores. In a more preferred embodiment, the manifold or collection chamber is formed at least in part by a longitudinal recess, preferably a longitudinal slot formed in the side bar. The slot is arranged such that when the side bar is attached to the plate portion, the recess is aligned with the collection bores in order to establish fluid communication with the recess or slot. At least one fitting is carried by the side bar which conveys fluid from the recess to a discharge conduit. In the preferred embodiment, a control valve controls the communication of the recess formed in the side bar, with the discharge conduit. The control valve may be remotely controlled.

The invention provides a method for operating a platen press that improves cycle time and controls the release of process byproducts. In particular, the platen is provided with a plurality of collection bores in a plate portion which are in fluid communication with one of the platen planar surfaces, preferably the lower surface, via vent passages. A collection chamber is provided for collecting the byproducts received in the collection bores. In the preferred method of operation, material to be processed is placed on a top surface of the platen. The platen press is then closed in order to place a clamping force on the material. Closure of the press is maintained for a predetermined amount of time. Upon conclusion of the processing cycle, but prior to opening the press, a control valve that controls the communication of the collection chamber with a discharge conduit, is opened in order to allow the processed byproducts collected by the collection bores to be discharged to the discharge conduit. As a result of the invention, the press can be opened much more quickly. In prior art platen presses, the press must be opened slowly in order to allow the slow discharge of the processed byproducts, so that the material carried by the platen is not damaged.

The present invention also provides a method for upgrading or retrofitting existing platens. In the preferred upgrade method, a side bar forming part of the platen is removed to expose a side edge of a plate portion forming part of the platen. A plurality of transversely extending collection bores is then machined into the plate portion with the bores commencing from the plate portion edge. The collection bores extend transversely across the plate portion but are spaced from fluid passages that form part of the plate portion and which define a heating circuit. A plurality of vent passages are then machined into the plate portion. The vent passages extend from one of the planar surfaces, preferably the lower surface of the platen, and an associated collection bore. A longitudinal recess is then formed in the side bar and defines at least in part a collection chamber in fluid communication with the collection bores, when the side bar is reattached to the plate portion. At least one outlet fitting is preferably secured to the side bar and provides the means for delivering process byproducts collected by the recess to a discharge conduit. In a more preferred embodiment, a control valve is disposed between the fitting and the discharge conduit to control the fluid communication between the outlet and conduit.

According to a feature of this retrofitting process, turnaround plates are secured in notches formed in the plate portion in order to isolate heating circuit fluid passages from the side bar. With the present invention, substantial improvements can be made to the speed with which a platen press operates without comprising the quality of the material processed by the press.

Additional features of the invention will become apparent and a fuller understanding obtained by reading the following detailed description made in connection with the accompanying drawings. Brief Description of Drawings

Figure 1 is a perspective view of a platen type press including platens constructed in accordance with the preferred embodiment of the invention;

Figure 2 is a side elevational view of a platen constructed in accordance with the preferred embodiment of the invention with portions removed to show interior detail;

Figure 3 is a sectional view of the platen as seen from the plane indicated by the line 3-3 in Figure 2;

Figure 4 is a fragmentary, sectional view as seen from the plane indicated by the line 4-4 in Figure 2;

Figure 5 is an enlarged, fragmentary view of the lower left corner portion of the platen as viewed in Figure 3;

Figure 6 is an enlarged, fragmentary side view of the platen;

Figure 7 is an enlarged, fragmentary cross-sectional view as seen from the plane indicated by the line 7-7 in Figure 2;

Figure 8 is a fragmentary top, plan view of the platen; and,

Figure 9 is a fragmentary side elevational view of the platen.

Best Mode for Carrying Out the Invention

Figure 1 illustrates the overall construction of a multiple platen press which includes a fixed upper bolster 10 and a movable lower bolster 12, between which are positioned a plurality of movable platens 14. In accordance with the invention, one or more of the movable platens 14 may be constructed in accordance with the preferred embodiment of the invention. The movable bolster 12 is moved upwardly by several main ram cylinders 16, and by a plurality of jack ram cylinders 17 which are positioned in a balanced and symmetrical manner. The construction of the main ram cylinder 16, the jack ram cylinder 17 and the hydraulic system for extending and retracting the cylinders 16 and 17, is conventional and does not form part of the invention.

Each of the movable platens 14 is connected to a plurality of control cylinders 18 which are arranged in four groups of cylinders 20, 22, 24, 26, each group being mounted on a separate support assembly 28 which is pivotally connected at one end to the fixed upper bolster 10. The other end of the support assembly 28 is pivotally connected to the upper end of a pivot arm 30 which is pivotally attached at its lower end to a bracket 32 fixed to the movable lower bolster 12. In operation, the movable platens 14 are clamped between the movable lower bolster 12 (which moves upwardly) and the fixed upper bolster 10. The lower bolster 12 is moved upwardly by the main ram cylinders 16 and the jack ram cylinder 17.

Each of the movable platens 14 is connected to four or more adjusting cylinders 18, each form a different one of the four or more groups of cylinders 20, 22, 24, 26 adjacent to the four corners of the platen. These four control cylinders maintain the platen level in a precisely adjusted spacing relative to its adjacent platen. The control system and hardware for achieving the control movement of the lower bolster 12 and platens 14 is considered conventional. A detailed description of the mechanism by which the movement in the platens is controlled can be found in U.S. Patent 5,634,398, owned by the present assignee and hereby incorporated by reference.

As is also conventional, the press, including the main and jack ram cylinders 16 and 17, is mounted on a fixed frame 34 secured to a concrete pad by legs 36 in a conventional manner. Each of the main ram cylinders 16 includes a piston 38 which is secured to the bottom of the movable lower bolster 12 and is movable upwardly in a parallel relationship with a plurality of vertical guide rods or columns 40. In like manner, each of the jack ram cylinders 17 includes a piston 41 which is secured to the bottom of the movable lower bolster 12 and aids in the movement of the lower bolster. The upper bolster 10 is fixed to the frame by attachment to the top of the guide rods 40 and to a press cap 42 in a conventional manner.

As is conventional, material to be processed is loaded onto each of the platens 14. The main and jack ram cylinders 16, 17 are connected to a source of fluid pressure which causes associated pistons to extend, thus raising the lower bolster 12. Concurrent with raising of the lower bolster 12, the control cylinders 18 are also raised due to the interaction of the pivot arm, thus raising the common support assemblies 28 upwardly. This motion raises all of the control cylinders 18 and, thus, raises the movable platens 14. The movement of the platens 14 is coordinated with the movement in the lower bolster so that all platens move to abutting contact concurrently, rather than sequentially as would occur if only the lower bolster 12 was used to move the platens 14 into abutting contact with each other.

As is known, a platen press of the type illustrated in Figure 1 is used to process, cure, or vulcanize sheet material. In general, material to be processed is laid on the upper surface of each platen 14. After the material is placed on the platens 14, the press is closed, as described above, clamping the platens 14 together in a tight confronting relationship. The cylinders 16, 17 apply a desired clamping pressure so that the material to be processed, located between the platens, is under constant pressure during the processing cycle.

The platens 14 are of the type that heat the material being processed, during the processing cycle. The means for heating the platens 14 is considered conventional and, in the illustrated embodiment, the platens 14 include passages through which a heating medium, such as hot oil, is conveyed through in order to transfer heat to the platens 14.

As is also known, during the processing of at least some materials, water vapor (steam) or other gas may be generated within the material which eventually is released.

In prior art constructions, the water vapor or other gas is usually released as the press opens and the platens 14 separate. In many prior art constructions, the opening of the press and separation of the platens is carefully controlled so that the release of the gases occurs slowly thus reducing the likelihood of disturbances to the processed materia. As a result, the cycle times for these types of presses can be increased substantially due to the slow opening of the press.

In accordance with the invention, at least one, but preferably all of the platens 14 include a means for releasing water vapor or other process gases throughout the processing cycle. As a result, the opening of the press can be effected much more quickly since a build-up of water vapor or gas, during the processing cycle can be more quickly discharged prior to opening of the press, allowing the press to be opened more quickly.

The overall construction of a platen 14 made in accordance with the preferred embodiment of the invention, is illustrated in Figures 2-4. As seen in Figures 2 and 3, the platen 14 is plate-like in construction and is preferably constructed of a rigid metal, such as steel. The platen may be formed as a single unitary structure, but in the illustrated embodiment, is a weldment made up of separate components. The platen 14 includes a heating plate portion 100 and side bars 102, 104 which are secured as by welding to side edges 106a, 106b of the plate portion 100. It should be noted here that the plate portion 100 is shown as a unitary member, but it should be understood that it too may be comprised of multiple plate-like portions that are welded together to define the overall plate portion 100.

The side bar 104 is shown in phantom in Figure 2. The plate portion 100 defines a passage through which the heating medium is conveyed and which heats the platen as it travels along the passages. In the illustrated embodiment, the plate portion includes two circuits (but may include more or less individual circuits). In particular, an inlet 114, located at the upper left corner of the platen 14 (as viewed in Figure 2) delivers the heated fluid medium to a leftmost passage 116a (as viewed in Figure 3). As seen in Figure 2, the heating plate portion 100 includes a plurality of the passages 116a, most of which extend the full width of the platen portion 100. In the preferred embodiment, the passages 116a are formed by elongate bores, which are best shown in Figure 3. The adjacent bores 116a are cross communicated by turnarounds 118a, 118b. The turnarounds are formed by elongate slots that are milled into the edge of the platen plate portion 100 and have a lateral extent corresponding to the spacing of two adjacent bores 116a.

As should be apparent, the bores 116a and turnarounds 118a, 118b define a continuous fluid circuit that commences at the inlet 114 and terminates at an outlet 120, which in the illustrated embodiment is located near the center of the platen 14. In the illustrated embodiment, the heated medium traveling through the fluid circuit located between the inlet 114 and the outlet 120 heats substantially one half of the platen plate portion 100.

Similarly, the right half of the platen plate portion 100 (as viewed in Figure 2) includes a plurality of passages 122a that are cross communicated by turnarounds 124a, 124b. The fluid circuit defined by the passages 122a and turnarounds 124a, 124b receives heated medium from an inlet 128 and discharges the heated medium through an outlet 130, also located centrally with respect to the platen 14. The outlets 120, 130 may join and form a single combined outlet that communicates with a return line (not shown) connected to the source of the heated fluid medium.

In the illustrated embodiment, the side bar 102 defines one side of each turn around 118a. In particular, surface portions 102a of the side bar 102 close off the notches in the plate portion 100 and thus define an outer wall of each turn around 118a.

In the preferred and illustrated embodiment, outside walls of the turnarounds 118b are defined by individual plates 132 which are welded across the notches formed in the side of the plate portion 100 to which the side bar 104 is fastened.

In accordance with the invention, a plurality of transverse, collection bores 140 are formed in the plate portion 100. As seen best in Figures 5, 6 and 7, the bores 140 are formed as by drilling between the heating passages 116a and at a level that is below a centerline 142 of the passages 116a (see Figure 6). In the preferred and illustrated embodiment, the collection bores 140 are substantially smaller in diameter than the fluid passages 116a and extend substantially the full width of the plate portion 100. Preferably, the bores stop short of the side edge 106a of the plate portion (see Figure 3) so they do not open into the inside surface 102a of the side bar 102 (also Figure 3). However, it should be noted that for some constructions, the bores 140 may extend entirely through the plate portion 100 and rely on the side bar 102 to seal off the ends of the collection bores.

As seen best in Figure 7, a plurality of vent passages 150 are machined into the plate portion 100 that are aligned with and spaced along each collection bore 140. As seen in Figure 7, the vent passages 150 extend from an associated collection bore 140 and open into a bottom surface 100a which is generally in contact with the material being processed during a processing cycle. For the platen 14 shown in Figures 2-3, there would be 27 collection bores 140 machined into the plate portion 100 and 23 vent passages 150 would extend from each collection bore 140 to the bottom surface 100a of the platen. During a processing cycle, water vapor or other gases discharged by the material being processed travels to the collection bores 140 via the vent passages 150.

In accordance with the invention, the side bar 104 includes a manifold structure for receiving the vented water vapor and other gases from the collection bores 140. In the preferred embodiment and referring in particular to Figures 8 and 9, the side bar 104 includes a collection chamber 160 which communicates with the ends of each collection bore 140. In the preferred and illustrated embodiment, the collection chamber 160 may be formed by milling a longitudinal slot in the side bar 104 which is aligned with the openings of the collection bores 140 when the side bar 104 is attached to the plate portion 100. The side bar 104 also preferably includes a plurality of outlet bores 164 spaced along the side bar 104 and in fluid communication with the collection chamber 160. The water vapor or other gases are collected in the chamber 160 are discharged through the outlet bores 164 which may be connected to conduits via fittings 164a for conveying the vented water vapor and gas to a remote location for disposal or further processing.

In the preferred embodiment, the discharge of water vapor and gas through the outlet bores 164 is controlled. In particular, the steam and gas byproducts are not discharged from the press until the end of the processing cycle. To achieve this preferred methodology, the outlet bores 164 would be connected to a common exhaust conduit which includes an ON/OFF valve. During most of the processing cycle, the valve (not shown) is in a closed position. Just prior to opening the press, the valve would be opened in order to allow the steam and other gaseous byproducts to be discharged just prior to opening of the press. The valve may be remotely controlled or manually controlled and, depending on the application, multiple valves and exhaust conduits may be employed.

As should be apparent from the above description, the disclosed invention provides a new and improved platen construction which provides a means for exhausting water vapor or other gases during the processing cycle itself. As a result, the build-up of pressure from the discharged water vapor and gases substantially reduces the risk of damage or flaws in the material being processed when the platen press is opened at the conclusion of the cycle. According to a feature of the invention, the venting apparatus can be retrofitted to an existing platen. In particular, to install the venting apparatus into an existing platen of the type having the heating circuitry and passages shown in Figure 2, the side bar 104 would be removed from the edge 106b of the platen portion 100 using known techniques, such as milling. Once the side bar 104 is removed, plates 132 can be secured as by welding across adjacent heating passages 116a, 122a so that the side bar 104 is no longer relied upon to serve as part of the structure for defining the turnarounds 118b. The edge 106b of the plate portion 100a made be machined to accept the turnaround plates 132.

The collection bores 140 are then formed, as by drilling, into the plate portion 100. The vent passages 150 are then machined into the platen portion 100 by drilling the vent passages 150 from the surface 100a and into the collection bores 140.

A collection chamber 160 is then formed in the side bar 104 by preferably milling a slot on the inside of the side bar 104, such that when the side bar is installed, the slot 160 communicates with the ends of the collection bores 140. Finally, outlet passages 164 are formed along the side bar 104 at suitably spaced locations which communicate with the slot 160 and which include fittings 164a that may be connected to conduits for conveying the discharged water vapor and gases away from the platen 14. After the side bar 104 is modified as disclosed, it is reattached to the side 106b of the platen portion as by welding. It should be noted here that the actual spacing and location of the outlet passages and fittings 164, 164a is usually determined by other components and structures that are attached to, or form part of the side bar 104.

Although the invention has been described with a certain degree of particularity, it should be understood that those skilled in the art can make various changes to it without departing from the spirit or scope of the invention as hereinafter claimed.

Claims

CLAIMSWe Claim:

1. A platen for supporting material to be processed in a platen press, comprising: a) a plate portion defining substantially planar upper and lower surfaces; b) a fluid circuit in said plate portion for conveying a heated fluid through said plate portion, said circuit having an inlet and an outlet; c) a plurality of collection bores formed in said plate portion for collecting byproducts generated during a processing cycle;

. d) a plurality of vent passages extending from a collection bore and to an associated one of said upper and lower surfaces; and, e) structure for receiving the byproducts collected by said collection bores and delivering said collected byproducts to at least one discharge conduit.

2. The platen of claim 1 wherein said at least one discharge conduit includes an on/off valve for controlling the discharge of the byproducts.

3. The platen of claim 1 further including a side bar attached to a side edge of said plate portion, said side bar defining a collection chamber in communication with said discharge conduit, said collection chamber forming at least a part of said structure and being in fluid communication with said collection bores.

4. The platen of claim 3 wherein said collection chamber is defined at least in part by a longitudinal slot formed in said side bar, in alignment with ends of said collection bores.

5. The platen of claim 2 wherein said on/off valve is remotely controlled.

The platen of claim 1 wherein said vent passages extend between said lower surface and said associated collection bore.

7. A method for operating a platen press, comprising the steps of: a) providing at least one platen, said platen assembly including: i) a fluid circuit having an inlet and an outlet for heating a plate portion of said platen; ii) providing a plurality of collection bores in said plate portion for collecting byproducts generated during a processing cycle; iii) providing a plurality of vent passages associated with each collection bore, said vent passages extending from an associated collection bore to at least one planar surface defined by said plate portion; iv) providing a manifold for receiving said process byproducts from said collection bores; v) providing a control valve for controlling the communication of said manifold with a discharge conduit; b) placing material to be processed on top surface of said platen; c) closing said platen press in order to place a clamping force on said material; d) maintaining closure of said press for a predetermined amount of time; e) upon conclusion of a processing cycle, but prior to opening said press, actuating said control valve in order to allow process byproducts collected by said collection bores to be discharged to said discharge conduit.

8. A method for upgrading a platen of the type that includes a plate portion having passages formed therein for defining a heating circuit and at least one side bar attached to an edge of said plate portion, said side bar including inlet and outlet fittings for said fluid circuit, comprising the steps of: a) removing said side bar; b) machining a plurality of transversely extending collection bores in said plate portion, said bores commencing from a plate portion edge exposed by removal of said side bar, said collection bores extending transversely across said plate portion, but spaced from fluid passages that define said heating circuit formed within said plate portion; c) machining a plurality of vent passages extending from a planar clamping surface defined by said plate portion and an associated collection bore; d) forming a longitudinal recess in said side bar, said longitudinal recess located and dimensioned such that when said side bar is reattached to said plate portion edge, said longitudinal recess is in fluid communication with said collection bores; and, e) providing an outlet fitting communicating with said longitudinal recess whereby process byproducts collected by said collection bores are discharged from said platen.

9. The platen of claim 1 , wherein said platen comprises two plate portions, each plate portion defining an associated fluid circuit.

10. The platen of claim 1 , wherein said collection bores have a diameter less than a diameter of passages forming said fluid circuit.

11. The platen of claim 1 , wherein said structure for receiving the byproducts collected by said collection bores is formed at least in part in a side bar that is attached to an edge of said plate portion.

12. The platen of claim 1 , further including another side bar attached to an opposite edge of said plate portion.

13. The platen of claim 11 , further including a plurality of turnaround plates secured to said plate portion, said turnaround plates isolating passages forming said fluid circuit from said side bar.

14. The platen of claim 1 , wherein said collection bores are arranged in parallel alignment.

15. The apparatus of claim 14, wherein said collection bores are disposed below a centerline of said platen and each of said collection bores communicates with said lower surface of said platen via a plurality of associated vent passages.

16. The platen of claim 3, wherein said collection chamber is defined at least in part by a recess formed in said side bar, said recess being in fluid communication with said collection bores.

17. The apparatus of claim 16, wherein said side bar mounts at least one fitting in fluid communication with said collection chamber.

18. The method of claim 7, wherein said plurality of vent passages provided in step iii) extend from an associated collection bore to a lower planar surface defined by the plate portion.

19. The method of claim 7, further comprising the steps of: a) providing a side bar attached to an edge of said plate portion, and; b) forming at least a portion of said manifold in said side bar.

20. The method of claim 7, further comprising the step of providing a plurality of platens and wherein said clamping force that is exerted on said material is exerted by a lower planar surface defined by an adjacent platen.

21. The method of claim 8, further comprising the step of installing turnaround plates in said plate portion in order to isolate said heating circuit passages from said side bar.

22. The method of claim 21 , further comprising the step of connecting said outlet fitting to a discharge conduit including a control valve for controlling the communication of said outlet fitting with said discharge conduit.