Patent Publication Number: US-11045857-B2

Title: Fluid-cooled ToolPack

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not applicable to this application. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable to this application. 
     BACKGROUND 
     Field 
     Example embodiments in general relate to a fluid-cooled toolpack for cooling can-forming dies used for the final forming of metal containers. 
     Related Art 
     Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field. 
     In can-making equipment, metal cans are generally formed by a bodymaker punch or ram that draws and irons metal cup blanks. The bodymaker makes containers by deepening the cup and reducing the wall thickness as the ram moves axially through the bodymaker, until a can with the modern well-known shape is formed. Typically, toolpacks are used in conjunction with the ram to provide controlled reduction in the thickness of the container wall as it is drawn and ironed in the bodymaker. A by-product of this process is unwanted heat in the equipment. In some conventional can makers, the dies are cooled with liquid, such as water, that is not isolated from the can-making process—in other words, the liquid can and does make contact with the cans, the dies, and the ram. As a result, the cans require additional cleaning steps before they are ready for finishing and use. 
     SUMMARY 
     The invention generally relates to an isolated heat transfer apparatus for can making equipment. An example embodiment comprises a ring-shaped chill plate in intimate contact with a die, and further includes embedded heat pipes to carry heat away from the interface between the die and the chill plate. The example embodiment also includes a heat transfer device to further transfer heat from the heat pipes to a cooling medium that flows over a series of cooling fins. 
     In use, the can-making process will generate heat in the dies which must be removed. In other systems, unwanted heat is removed by allowing cooling and lubricating fluid to flow over the inner portion of a bodymaker during can making. This fluid must then be removed in a separate process before cans can be finished, filled and used. In an example embodiment, instead of direct liquid cooling, heat pipes are used to carry heat away (or toward) the chill plate  10  and thus the associated dies, which cools the dies without allowing any cooling fluid to contact the cans being made or the interior of the can bodymaker. 
     In operation, the heat generated by the can making process (i.e., drawing and ironing) is transferred first from the die  43 , which is in thermal contact with the chill plate  10 . Specifically, the chill plate  10  is in contact, or thermally coupled, to the backside of the die  43 . By locating the chill plate on the backside of the die, the chill plate is not subjected to direct force when the ram pushes a can through the die. Heat is then transferred from the body of chill plate  10  into the heat pipes  11  around the chill plate  10  to the heatsink fins  12  near the top of the toolpack module  20 , and the heatsink fins  12  in turn are cooled by a cooling medium, which flows over the heatsink fins  12  within shroud  13 , using fluid-tight connections to prevent fluid from entering the interior of toolpack module  20 . The cooling fluid is isolated from the interior of the can bodymaker. 
     The chill plate  10  may include a temperature sensor  50 , which can be used in conjunction with a controller  62  to regulate the temperature of the chill plate. If so, the controller can be used to control a valve  61  that controls the flow of cooling fluid supplied to the heatsink fins  12  of the chill plate, through the bodymaker cradle lid. Temperature control is not necessary, however, and alternatively, the chill plate can be used to remove heat as determined by the thermal efficiency of the chill plate  10 , as well as the flow rate and temperature of the cooling fluid. 
     There has thus been outlined, rather broadly, some of the embodiments of the fluid-cooled toolpack in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional embodiments of the fluid-cooled toolpack that will be described hereinafter and that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the fluid-cooled toolpack in detail, it is to be understood that the fluid-cooled toolpack is not limited in its application to the details of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. The fluid-cooled toolpack is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein like elements are represented by like reference characters, which are given by way of illustration only and thus are not limitative of the example embodiments herein. 
         FIG. 1  is a sectional perspective view of a toolpack module in accordance with an example embodiment. 
         FIG. 2  is another perspective view of a toolpack module in accordance with an example embodiment. 
         FIG. 3A  is an end view of a toolpack module in accordance with an example embodiment. 
         FIG. 3B  is a top view of a toolpack module in accordance with an example embodiment. 
         FIG. 3C  is a side view of a toolpack module in accordance with an example embodiment. 
         FIG. 4  is a sectional side view of a toolpack module in accordance with an example embodiment taken along line A-A of  FIG. 3A . 
         FIG. 5A  is an end view of a chill plate in accordance with an example embodiment. 
         FIG. 5B  is a side view of a chill plate in accordance with an example embodiment. 
         FIG. 5C  is a top view of a chill plate in accordance with an example embodiment. 
         FIG. 6A  is an end view of a chill plate and chill plate retention ring in accordance with an example embodiment. 
         FIG. 6B  is a top view of  FIG. 6A  in accordance with an example embodiment. 
         FIG. 7  is an exploded perspective view of a chill plate, retention ring, and spacer in accordance with an example embodiment. 
         FIG. 8A  is an exploded perspective view of a chill plate in accordance with an example embodiment. 
         FIG. 8B  is an alternative end view of a chill plate in accordance with an example embodiment. 
         FIG. 9  is cross sectional view of a toolpack module installed in a bodymaker cradle in accordance with an example embodiment. 
         FIG. 10  is schematic of a chill plate and associated temperature control and cooling/heating components in accordance with an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A. Overview 
     An example embodiment of a fluid-cooled toolpack generally comprises an apparatus that removes heat from the can making process without exposing the dies, ram, or cans to the cooling medium. The fluid-cooled toolpack provides for the cooling of can-forming equipment with a fluid (i.e., liquid or gas) that is isolated from the interior cavity of the bodymaker. As known in the can making industry, a bodymaker typically comprises a number of toolpack modules held in a bodymaker toolpack cradle  30 . In an example embodiment, the bodymaker can include multiple floating die modules  40  that employ floating die module springs  41  and floating die module support pins  42  to hold can-forming dies  43  in place while still allowing the dies to float and self-center. As the ram moves into the bodymaker, each die progressively thins the walls of the can and deepens the can. Further, in the example embodiment, the multiple can-forming dies  43  are separated by spacers  21 . 
     The fluid-cooled toolpack generally includes a chill plate  10  that is biased into intimate contact with a floating die by a chill plate spring  15 . The surface of the chill plate contacts the back surface of the die so that there is good heat transfer between the die and the chill plate. The chill plate  10  may be generally ring shaped, and may further include one or more heat pipes  11  that carry heat away from the chill plate to a number of heatsink fins  12 . The heatsink fins  12  may be contained in a shroud  13  having inlets/outlets  14  for directing and containing a cooling fluid (e.g., air or water) which flows over the heatsink fins  12 , further removing heat from the can-making process by transferring it to the cooling fluid. 
     Because it is spring loaded and contacts the back side of a die, an example embodiment of the fluid-cooled toolpack can advantageously be used on a “floating die” toolpack assembly like the one disclosed in U.S. Pat. No. 4,554,815, which is hereby incorporated by reference in its entirety. As disclosed in the &#39;815 patent, in a floating toolpack assembly, the ironing and guiding dies are allowed to move or “float” in a radial direction to compensate for any shift in alignment between the ram and the dies. This float allows for automatic centering of the dies and results in better operation of the toolpack. The floating dies may also rotate within the floating die module due to forces generated by the can-making process—such as by off-center hits—which, combined with the radial float, reduces wear on the bodymaker, dies, and ram. 
     B. Chill Plate 
     One component of an example embodiment of the invention, as discussed briefly above, is a chill plate  10 . The chill plate  10  may advantageously be mounted to contact the back side of its associated can-forming die  43 , so that forces from the ram are not transferred to the chill plate  10 , and also so that the front surface of chill plate  10  is constantly biased into contact with the can-forming die  43  while also allowing the die to float as described above. 
     As best shown in  FIGS. 8A &amp; 8B , the back side of chill plate  10  has a number of generally annular-shaped grooves that accept heat pipes  11 , which effectively transfer heat away from the chill plate and its associated can-forming die and into the heatsink fins  12 . The operation of heat pipes is well known and will not be repeated at length here. The important principle is that heat pipes are capable of transferring energy, in the form of heat, from one point to another with very high efficiency. In the example embodiment, when used to cool a die, the annular portion of the heat pipes are the “hot” end, and the ends that are in contact with the heatsink fins are the “cold” end. Notably, the direction of heat transfer can be reversed if it is desired to preheat the can-forming die or dies, which may be desirable in a number of circumstances. 
     For example, part tolerances in can-making equipment are extremely tight, and can be affected by temperature; thus, a user may want to preheat the dies to a temperature near the working temperature before starting the can-making process to ensure accuracy. As also shown in  FIGS. 8A &amp; 8B , the chill plate may include an RTD (resistance temperature detector) or other temperature sensor to measure and control the temperature of the chill plate by regulating the flow of the cooling fluid over the heatsink fins. The RTD may have surface mounted or embedded leads (not shown) to conduct a temperature signal to contact points that may be contacted by corresponding contact points in the cradle lid  31 , or another part of the bodymaker, so that no separate connectors or wiring is needed to measure the temperature. Alternatively, the temperature signal may be transmitted to other points in the system via wireless data transmission. In this way, simply installing the toolpack module in the bodymaker toolpack cradle will establish the electrical connection for the temperature sensor. 
     Although other algorithms can be used, the temperature of the chill plate can be controlled using a simple closed loop proportional control, shown schematically in  FIG. 10 . In a closed loop mode, the chill plate temperature is constantly measured by RTD  50  or other temperature sensor. The measured temperature is an input to controller  62 , which compares it to a setpoint, and the error (the difference between the measured temperature and the setpoint) is used to drive a device, such as valve  61 , to cause the measured temperature to move toward the setpoint temperature. The cooling fluid can be circulated to chill plate  10  by a pump  60 , or may be supplied from a water line or other source. In addition to a valve  61 , other devices may be controlled, such as heaters or coolers. In use, if the chill plate temperature is higher than the setpoint, the controller  62  can open valve  61  to increase the flow of cooling fluid over the heatsink fins to decrease the temperature of the chill plate  10  and, correspondingly, the die  43 . In an example embodiment, the control signal sent to valve  61  can be proportional to the temperature difference between the setpoint and the measured temperature. Since heat pipes are not directional, this same process can also be used to increase the temperature to preheat the chill plate and associated die, as discussed above. 
     As with other heat pipes, the heat pipes of the example embodiment have a working fluid that evaporates where the temperature is high and condenses where it is lower. The heat pipes  11  may have a round cross section, or as in an example embodiment, may be somewhat flattened as shown in  FIG. 8A . The heat pipes, especially if flattened, may be flush with or below the back surface of the chill plate (i.e., the surface opposite the die) to prevent damage and to maximize heat transfer. In the example embodiment, the condensed working fluid can flow back to the hotter portion of the heat pipes by gravity. As shown in  FIG. 8A , the heatsink fins  12  may be positioned at or near the top of the chill plate to facilitate the flow of the condensed working fluid back to the hotter region of the chill plate  10 . 
     In an example embodiment, the annular portion (i.e., the “hot” end) of heat pipes  11  are designed to fit tightly into the set of heat pipe grooves  17  formed in one side of the chill plate  10 . The heat pipes may be press fit into grooves  17 , or they may be chemically bonded in place. They may also be soldered in place. The other, “cold” end of the heat pipes  11  may be bonded, press fit, or soldered to a plate or other structure that holds the set of heatsink fins  12 , to effectively transfer heat to them. The junction between the heat pipes and the chill plate and the heatsink plate is designed for maximum contact and thus good heat transfer. As best shown in  FIG. 6B , the heatsink fins  12  may be enclosed in a heatsink shroud  13  that will contain and isolate the cooling medium (or heating medium, depending on the application) from the interior cavity of the bodymaker. The cooling medium, such as water or air, enters and leaves the heatsink assembly via cooling media inlets/outlets  14 , which allows the heatsink fins  12  to be exposed to and cooled (or heated) by the medium. 
     As shown in  FIGS. 4 &amp; 7 , the chill plate  10  is held in place on a spacer  21  by a chill plate retention ring  16 , which allows the chill plate  10  to move axially (i.e., along the same axis as the ram, indicated by the arrow in  FIG. 1 ). As discussed, the chill plate  10  is held against the die  43  by chill plate spring  15 . The chill plate spring  15  may be an annular wave spring (see  FIG. 8A ) as shown, but could also be comprised of multiple coil springs or an annular spring made from a resilient material, such as a compressible polymeric material. As best shown in  FIGS. 1 &amp; 7 , the wave spring  15  may be retained in an annular spring groove  23  in spacer  21 , although other configurations are possible, such as a channel in the chill plate  10  or holes in the spacer  21  to retain coil springs. 
     A small amount of movement of the chill plate may be desirable so that the chill plate spring  15  can urge the front surface of the chill plate  10  into close contact with the back side of an associated can-forming die  43 , resulting in good thermal coupling. The retention ring  16  holds the chill plate  10  in place in the bodymaker, while at the same time allowing it to move as noted. The retention ring  16  is screwed into spacer  21  with countersunk screws  19 , and the innermost portion of the retention ring  16  contacts the shoulder  18  of the chill plate  10  to hold it in position both radially and axially. 
     C. Floating Die Module and Spacer 
     The example embodiment may be used with a bodymaker comprising one or more floating die modules. As discussed briefly above, each floating die module holds a can-forming die  43  in place with multiple floating die module springs  41  and floating die module support pins  42  that hold the die in place while allowing it to float and self-center in the event of off-center hits from the ram, or misalignment from any cause. As shown in  FIG. 2 , two dies (or more) can be used in the example embodiment, separated by a spacer  21 . The spacer  21  can also include a vacuum or waste port  22  for the removal of swarf or debris created during the can-making process. The waste port  22  connects the interior of the spacer  21  to the exterior of the spacer, where any unwanted material in the interior of the spacer can be removed, for example, by a vacuum line attached to or manifolded to, the waste port  22 . As also shown in  FIG. 2 , the spacer  21  creates a gap between the floating die modules. This space allows room for the heatsink fins  12  and heatsink shroud  13  between the dies  43 . 
     As best shown in  FIG. 7 , the spacer  21  and chill plate  10  can be assembled into a unit that is robust enough for industrial environments, while at the same time, the spring-biased attachment of chill plate  10  to spacer  21  allows the chill plate  10  to move into contact with the can-forming die  43  to establish good thermal coupling. As also shown, posts in the spacer  21  can be inserted through the heatsink fins  12  of the chill plate  10 , and then screws  19  pass through holes in the retention ring  16  and into the posts, further securing the chill plate in the assembly. 
     The spacer  21  provides a mounting base for the chill plate  10 , chill plate retention ring  16 , and also provides a base for chill plate spring  15 , which biases the chill plate  10  away from the spacer  21  and toward die  43 . Together, the spacer  21  and the floating die modules, the dies  43  and the chill plate  10  comprise a toolpack module  20 . As is known, the toolpack module is designed and constructed for placement into a bodymaker toolpack cradle  30  as shown in  FIG. 9 . As also known, the bodymaker toolpack cradle  30  can hold other components used for making can bodies, such as a bottom former (not shown) as well as other bodymaker elements. The bodymaker  30  also includes a bodymaker cradle lid  31  which holds the toolpack module  20  firmly within the cradle. As best shown in  FIG. 9 , the bodymaker cradle lid  31  in an example embodiment includes a lid seal  32  and a number of lid inlets and outlets  33  that interface with the cooling inlets and outlets  14  of shroud  13 . Cooling or heating fluid can flow through the inlets and outlets as necessary to heat or cool the chill plate, without allowing the fluid to contact or contaminate the cans. The shroud surrounding the heatsink fins  12  as well as the lid seal/manifold  32  of the bodymaker cradle lid  31  keep the cooling fluid flowing just over the heatsink fins  12 , preventing it from entering the central portion of the bodymaker. 
     D. Operation of Preferred Embodiment 
     In use, the can-making process will generate heat in the dies which must be removed. In other systems, unwanted heat is removed by allowing cooling and lubricating fluid to flow over the inner portion of a bodymaker during can making. This fluid must then be removed in a separate process before cans can be finished, filled and used. In an example embodiment, instead of direct liquid cooling, heat pipes are used to carry heat away (or toward) the chill plate  10  and thus the associated dies, which cools the dies without allowing any cooling fluid to contact the cans being made or the interior of the can bodymaker. 
     The heat is transferred from the heat pipes  11  around the chill plate  10  to the heatsink fins  12  near the top of the toolpack module  20 , and the heatsink fins  12  in turn are cooled by a cooling medium, which flows over the heatsink fins  12  within shroud  13 , using fluid-tight connections to prevent fluid from entering the interior of toolpack module  20 . The isolation of the cooling fluid from the interior of the can bodymaker allows cans to exit the bodymaker in a clean state, 
     The chill plate  10  may include a temperature sensor  50 , which can be used in conjunction with a controller  62  to regulate the temperature of the chill plate. If so, the controller can be used to control a valve  61  that controls the flow of cooling fluid supplied to the heatsink fins  12  of the chill plate, through the bodymaker cradle lid. Alternatively, the chill plate can be used without a temperature controller, in which case the thermal efficiency of the chill plate  10 , as well as the flow rate and temperature of the cooling fluid, will determine how much heat is removed from the die. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the fluid-cooled toolpack, suitable methods and materials are described above. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. The fluid-cooled toolpack may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect.