Abstract:
An elongated structure ( 100 ) for the transmission of fluid-based compositions at non-ambient temperatures comprising a first conduit ( 130 ) for the transmission of a fluid-based composition, at least one flexible, elongated and inflatable temperature control conduit ( 110   a   , 110   b ) for the transmission of a temperature control fluid, the temperature control conduit ( 110   a   , 110   b ) having a relatively rigid elongated reinforcement member ( 116   a   , 116   b ); and elongated cover ( 140 ) holding said temperature control conduit ( 100   a   , 110   b ) in thermal communication with the first conduit ( 130 ).

Description:
TECHNICAL FIELD 
     The present invention relates generally to processes and devices for temperature regulation of fluid conduits, and more particularly to such a device and method wherein at least one flexible, expansible profile is positioned in thermal contact with a fluid conduit, and heated or chilled fluid is passed therethrough to regulate the temperature of fluid carried therein. 
     BACKGROUND OF THE INVENTION 
     There are a wide variety of applications where heated or chilled fluid is delivered over a length of conduit such as a hose or pipe. Typical industrial applications include fluid coatings or adhesives that are applied at specific assembly or processing stations in a plant. The fluid may thus be stored in an area remote from the one or more dispensing stations. Many commonly used industrial compositions vary in viscosity with changes in temperature. For example, spray coating thickness, texture and cure time may all be affected by variations in the viscosity of the sprayed materials. Improved reliability and repeatability of dispense patterns and characteristics in industrial processes are a benefit of maintaining the temperature of the applied materials within a pre-selected range. It is generally preferred to perform the bulk temperature control at the point of introducing the fluid into the system, particularly where there are multiple application points. During delivery of the fluid to the application station, a change in fluid temperature can result if the ambient temperature varies from the initial control temperature. The temperature gradient increases as the difference between the ambient temperature and control temperature increases and as the length of the conduit increases. 
     Engineers have developed various means for achieving the desired temperature control. Once such design is a flexible cover assembly having thermal fluid transfer tubes attached or embedded therein. Such an assembly is known from U.S. Pat. No. 5,363,907 to Dunning et al. In Dunning, the cover is secured about a fluid supply conduit, and heated or chilled fluid is passed through the tubes. This design has met with significant success, however, the materials heretofore utilized in the assembly tend to be relatively insulative. These materials, typically in the form of elastomeric, cylindrical tubes are generally ineffective in transferring sufficient heat between the fluid supply conduit and the thermal transfer fluid to aggressively change the temperature of the fluid in the conduit. 
     An alternative design relates to coaxial hoses or pipes wherein a thermal transfer fluid is passed through the space between the outer diameter of an inner hose or pipe and the inner diameter of an outer hose or pipe. One such design is known from U.S. Pat. No. 5,287,913 to Dunning et al., herein incorporated by reference. Such a design has been demonstrated to be more effective in aggressively changing the temperature of fluid in the fluid supply conduit than tube-in-cover designs, however, the outer hose may have a tendency to buckle or kink, and therefore block fluid flow when the coaxial assembly is bent or flexed. Thus, the hose can collapse in certain high motion applications, potentially resulting in mixing of fluids from the inner and outer hoses, or breaking and spillage of thermal transfer fluid out of the outer hose. A related concern involves the necessity for securing the hose with clamps at various points. Where the coaxial hose is used to deliver fluid to a movable spray device, for example, it may be necessary to clamp the hose to portions of the movable device at various points. In order to avoid collapsing of the hose from clamping force, designers have typically used a relatively bulky, heavy duty, spiral wound reinforced hose. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an efficient, flexible device for supplying thermal transfer fluid along an exterior of a fluid conduit. 
     It is a further object of the present invention to provide a coaxial hose arrangement for temperature regulation of a fluid conduit having secondary containment for thermal transfer fluid used therein. 
     In accordance with these and other objects, the present invention comprises a fluid transfer profile that includes a flexible outer wall attached to an integral mounting tab and a relatively rigid, longitudinal reinforcing rib. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an end view of a fluid transfer profile in accordance with a preferred embodiment of the present invention; 
         FIG. 2  illustrates a cross section of a set of fluid transfer profiles positioned in a coaxial hose assembly in accordance with the present invention; 
         FIG. 3  is an elevational view of an insulated cover assembly for use with fluid transfer profiles in accordance with the present invention; 
         FIG. 4  illustrates a cross section of an insulated cover assembly wherein a set of fluid transfer profiles according to the present invention are mounted; 
         FIG. 5  illustrates a coaxial hose assembly in accordance with a known system; 
         FIG. 6  illustrates a cover assembly in accordance with a known system. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is shown an end view of a fluid transfer profile  10  according to a preferred constructed embodiment of the present invention. Profile  10  is an elongate, hollow member formed from a flexible, thermally conductive polymer or other rubber material, and is contemplated for use in temperature control of fluid conduits by positioning profile  10  in intimate, thermal contact therewith. A suitable thermal transfer fluid is passed through profile  10  to regulate the temperature of fluid passing through the fluid conduit. Propylene glycol or similar materials, various mineral and organic oils, water and other fluids, both compressible and incompressible, might be used, depending on the heat transfer needs of the system, materials, and operating temperatures. Where greater or lesser temperature adjustment of the subject pipe is desired, the temperature and/or flow rate of fluid in the profile  10  can be adjusted. 
     The preferably arcuate inner surface  12  of profile  10  assists in optimizing the heat transfer properties of the system by maximizing physical contact between profile  10  and the subject conduit or pipe, which is typically substantially cylindrical. The cross sectional geometry of profile  10  may be tailored for particular applications. For instance, profile  10  might be fashioned to have a relatively greater area of surface contact with a fluid conduit than the examples in the drawing Figures, and a correspondingly flatter cross section. Similarly, larger or smaller profiles can be used to increase or decrease the fluid flow capacity, or the effective area of surface contact with the fluid conduit, depending on system requirements. The wall thickness of the profile along its side of contact with the fluid conduit can also be adjusted to provide varying degrees of thermal conductivity. A mounting tab  14  is preferably attached to an outer surface  18  of profile  10 , and is attached to a reinforcing rib  16  that extends longitudinally through a fluid transfer passageway  20 . Various methods may be employed in manufacturing profile  10  such as extrusion, molding, heat-sealing, embossing, etc. For example, profile  10  can be extruded as a single piece wherein mounting tab  14  and reinforcing rib  16  are formed integrally with relatively thin walls  11  of extrudate defining passage  20 . Alternatively, the walls  11  can be formed separately from tab  14  and rib  16 , and the components heat sealed or otherwise attached in any suitable manner. Although rib  16 , tab  14  and walls  11  are all preferably extruded from a substantially homogeneous material, the components might be made from differing materials for certain applications. For example, reinforcing inserts could be molded into either or both of tab  14  and rib  16  to enhance the strength of the assembly. Further, materials having relatively greater or lesser thermal conductivity can be used to form different parts of profile  10 . For example, a material having a relatively greater thermal conductivity might be used to form the portions of profile  10  that contact the fluid conduit, whereas a relatively more insulative material might be used for portions of profile  10  positioned opposite the fluid conduit. All the components of the present invention are manufactured from known materials and by known processes. 
     Referring to  FIG. 2 , there is shown an embodiment of the present invention  100  wherein a set of two profiles  110   a  and  110   b  are positioned in a coaxial hose assembly comprising inner and outer hoses  130  and  140 . In particular, the profiles  110   a  and  110   b  are positioned between the outside diameter of the inner hose  130  and the inside diameter of the outer hose  140 . It should be appreciated that “hose” encompasses any fluid transfer conduit, and the descriptions herein with respect to hoses  130  and  140  are equally applicable to other, similar items such as conventional pipes. As illustrated in  FIG. 2 , a pair of elongate reinforcing ribs  116   a  and  116   b  extend from a pair of mounting tabs  114   a  and  114   b  into fluid passages  120   a  and  120   b . Ribs  116   a  and  116   b  assist in preventing walls  111  from collapsing (kinking) when coaxial hose assembly  100  is bent, and preferably extend substantially along the entire length of the fluid passages  120   a  and  120   b . Mounting tabs  114   a  and  114   b  are preferably flexible, and may flex to conform to an inner contour of outer hose  140 . In a preferred embodiment, flexible mounting tabs  114   a  and  114   b  add flexible support to the assembly. The added support from mounting tabs  114   a  and  114   b , and the reduced need for a reinforced outer hose (since it does not directly carry the thermal transfer fluid) allow outer hose  140  to be made without an integral reinforcement such as a longitudinal metal coil. In addition, reinforcing ribs  116   a  and  116   b  prevent collapse of the fluid passage when the assembly is clamped, further reducing the need for sturdiness and thickness of outer hose  140 , further described below. Further still, because outer hose  140  can be made from lighter weight, more flexible, and less expensive materials than many earlier designs, the assembly is more flexible overall. Although two profiles are utilized in the  FIG. 2  embodiment, the present invention is not limited to such a design, and a greater number of profiles might be used for other applications. The flow of thermal transfer fluid through the profiles is preferably opposite, i.e. one of profiles  110   a  and  110   b  passes fluid in the same direction as the fluid transfer conduit or inner hose  130 , while the other of profiles  110   a  or  110   b  passes fluid in a direction opposite to that of inner hose  130 . Where a different number of profiles is used, they may be used alternately as fluid supply and return paths. 
     In a typical coaxial hose assembly according to the present invention, such as assembly  100 , machined, molded, or otherwise formed blocks are provided at opposite ends of the section of fluid conduit that is to be temperature-regulated. The blocks provide a manifold type arrangement whereby the thermal transfer fluid can be directed into its appropriate supply or return path(s), in a manner known in the art. Referring to  FIG. 5 , there is shown a coaxial hose assembly  300  in accordance with the prior art, illustrating a terminal block  301  for directing thermal transfer fluid through an outer hose  340  as well as directing a fluid supply through an inner hose  330 . 
     In alternative embodiments, sensing probes  150 , known in the art, may be inserted into gaps between the profiles and the outer hose  140 . If thermal transfer fluid escapes from passages  120   a  and  120   b , changes in the capacitance, resistance, pressure, etc., of the probes can be used to generate an electrical signal that notifies a control system or a technician that a potential spill and or system-down condition may be imminent. Outer hose  140  also serves as a secondary containment barrier for the thermal transfer fluid. This built-in spill-safe feature further reduces the risk of damage to equipment or product, as the outer hose can contain the thermal transfer fluid about the inner hose  130  for a period of time sufficient to allow proper shutdown of the system. For example, utilizing sensors to identify a potential leak problem before temperature regulation is compromised can allow the fluid supply conduits (inner hose  130 ) to be drained of material in advance of cooling in the system sufficient to allow solidification of material therein. Similarly, the early warning capability of the present design in conjunction with secondary containment could prevent chilled volatile compositions from arriving at their application points at too high a temperature for safe application. Thus, the present design provides significantly reduced risks of spills, system damage, and can even provide for safer system operation. These advantages are not provided by earlier designs wherein the thermal transfer fluid is carried directly by an outer hose. 
     Turning to  FIG. 4 , there is shown a cover assembly  200  that is yet another embodiment of the present invention. In assembly  200 , a set of profiles  210   a  and  210   b  are retained in pockets or sleeves  220   a  and  220   b  that are attached to a flexible cover  230 . Cover assembly  200  is primarily contemplated for use in established systems that require, for example, supplementary heating, however, cover assembly  200  might also be incorporated as part of an original system design. Cover  230  is preferably formed from a flexible fabric that can be wrapped around the pipe that is to be heated. Although conventional fabrics are preferred for most applications, for instance woven polyesters, nylons or other common polymers, where the temperatures encountered are relatively great, highly heat-resistance polymers or other suitable, non-polymeric materials may be used. Because cover  230  is preferably formed from multiple layers of material, various insulating layers may be incorporated therein, both to enhance the heat-resistance of the cover material itself and to improve the temperature control capabilities of the cover assembly. In one preferred embodiment, one or more layers of flexible insulation material, for instance fiberglass, is/are affixed between two layers of durable polymeric fabric. The layers can be glued, riveted, ultrasonically or thermally welded, or attached by any other known means. Most preferably, the layers are sewn together. Various combinations of insulating; protective or decorative materials may be used. 
     Pockets  220   a  and  220   b  may comprise longitudinal sleeves into which mounting tabs  214   a  and  214   b  are slid, or they may comprise, for example, discrete sets of clips or other retainers that overlap mounting tabs  214   a  and  214   b  when positioned therein. Further still, the means for attaching profiles  210   a  and  210   b  could be any suitable attachment, for instance, Velcro®, adhesives, stitches, etc. might be used without departing from the scope of the present invention. In a preferred embodiment, cover  230  is wrapped around a fluid transfer conduit, bringing profiles  210   a  and  210   b  into thermal contact therewith. Velcro® strips, identified with numeral  225  in  FIG. 4 , snaps, hooks, a zipper or some other means may be used for securing cover  230  about the subject conduit. Because it is desirable to effectively thermally isolate the environment within the wrapped cover from ambient, securing means are preferred which substantially block air exchange along the attached edges of the cover  230 . The dimensions of cover assembly  200  are variable, and will be greater or lesser depending on the length and diameter of the pipe whose temperature is to be adjusted. Similar to the foregoing embodiments, although two profiles are preferably used, other applications may call for a different number of profiles, and a correspondingly different number of pockets. In a preferred embodiment, cover  230  comprises an outer fabric layer  238 , and an inner, insulating layer  240 . Thermal transfer fluid passed through profiles  210   a  and  210   b  thus changes the temperature of the air and fabric between the insulative layer  240  and the fluid transfer conduit. The heated or chilled air and fabric provide extra insulation around the fluid transfer conduit. Further, the flexible fabric cover renders assembly  200  well suited to high motion/high angle applications.  FIG. 3  illustrates a schematic view of a fabric profile cover assembly  230  similar to the cover of  FIG. 4 . Identical numerals in  FIGS. 3 and 4  denote similar features. While a preferred embodiment of the present invention has been described in which a flexible, fabric cover is utilized, it should be appreciated that alternative embodiments are contemplated. For example, a relatively rigid, multi-piece hinged cover might be substituted so long as the profiles can be brought into intimate contact with the pipe when the cover is engaged therewith. 
     A typical installation process utilizing a cover assembly according to the present invention begins by selecting an appropriately sized and designed cover assembly. Cover assemblies according to the present invention may be any length or size, or have essentially any number of fluid transfer profiles, limited only by the length and diameter of the fluid conduit to be fitted, and the thermal exchange requirements of the system. Once the desired cover assembly is selected, the fluid conduit surface is prepared. This may include cleaning or otherwise treating the pipe surface to ensure the most effective transfer of thermal energy. Before applying the cover assembly, a thermal transfer material such as thermal transfer grease may be applied longitudinally along the arcuate surfaces of the profiles or the fluid transfer conduit. There are many such materials known in the art, and various greases, pastes, creams, and gels are readily commercially available. Further still, there are numerous dry, thermally conductive foams and tapes known in the art that may be applied, for example with a thermally conductive adhesive. Likewise, a low durometer thermally conductive polymer may be introduced during the fabrication phase of the profile and extruded, molded, heat fused, or otherwise bonded to the surface. The cover is wrapped circumferentially around the conduit and secured, preferably bringing the profiles into secure contact with the conduit, with the layer of thermal gap filler positioned between the conduit and profiles. Once secured, the profiles can be connected to the thermal fluid circulation system in any known fashion. 
     Referring to  FIG. 6 , there is shown an exemplary known cover assembly  400 . Cover assembly  400  provides a plurality of substantially cylindrical tubes  310  that are attached to a flexible cover  338 . Cover  338  is wrapped and secured around a fluid conduit, allowing heated or chilled fluid passed through tubes  310  to regulate the temperature of the conduit and fluid therein. Referring to the drawing Figures generally, profiles used in the practice of the inventive embodiments described herein, such as profile  10  are preferably flexible, and may therefore find particular application in environments where the fluid transfer conduit or hose whose temperature is to be regulated is flexible. For example, profile assemblies according to the present invention might be used to regulate the temperature of fluid applied to a part or a mold via an industrial sprayer with movable spray elements. In such a device, temperature control of the delivered fluid can be carried out in spite of the need to move the fluid delivery device, as the flexible profile can be maintained substantially in thermal contact with walls of the fluid conduit even when moved to varying positions. 
     The flexible nature of profile  10  allows thermal transfer fluid passed therethrough to “inflate” the profile, whereby the profile is expanded to fill gaps between the coaxial hoses, or in the case of the cover assembly, gaps between the fluid transfer conduit and the cover. Stated another way, the walls  11  of the fluid transfer passage  20  expand when thermal transfer fluid is passed into profile  10 . Expansion of profile  10  enhances heat transfer between the fluid supply conduit and the thermal transfer fluid by enhancing the surface to surface contact between profile  10  and the subject fluid supply conduit. 
     Returning to  FIG. 2 , illustrating coaxial hose assembly  100 , thermal transfer fluid supplied to passages  120   a  and  120   b  provides outward pressure against the inner diameter of second hose  140 . Similar to an inflating inner tube, the expansive outer pressure imparts additional rigidity to the assembly, without sacrificing overall flexibility. Thus, a larger clamping force than would otherwise be possible can be provided to assembly  100  without concerns of collapsing outer hose  140 . Varying degrees of fluid pressure may be provided to profiles  110   a  and  110   b , providing relatively greater or lesser rigidity, depending on the desired rigidity of assembly  100 . This characteristic is rather like increasing the gas pressure in an inflatable inner tube, wherein the inner tube increases in strength and rigidity as the internal pressure is increased. Because outer hose  140  is relatively rigid, it resists expansion as the fluid pressure in profile  110  is increased, gaining rigidity with increasing internal pressure. 
     The blocks for directing fluid that are preferably utilized in conjunction with the present invention (not shown) are preferably designed such that they can accommodate either of the above-described coaxial hose and cover assembly embodiments. These may be fabricated from a metal or plastic material such as aluminum, carbon or stainless steel, titanium, Delrin, PVC, polypropylene or any other material which may be formed to achieve geometries that are suitable to contain the pressures of a given system. These may be machined, molded, cast, or otherwise formed to create the various passages required to route the various fluids properly through the system. These blocks may also be fabricated with a port designed to allow placement of a temperature sensing probe directly into the path of the material to be temperature controlled to allow direct monitoring of the material&#39;s temperature for relaying to a controller, display, or any other appropriate device. Furthermore, these may be designed to include sensing probes as previously discussed that extend into the annular space between the inner hose, pipe or tube and outer layers for the purpose of sensing leakage of a fluid into that space. This feature may be in the form of a connector to which remote sensors may be attached such that the signal may be passed to the outside of the system and relayed to a host system. These sensors may be a point type, or may extend through the length of the assembly so as to detect leakage at the earliest possible opportunity. 
     The present description is for illustrative purposes only, and should not be construed to limit the breadth of the present invention in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the intended spirit and scope of the present invention.