Abstract:
O-ring or other fluid seal member ( 10 ) and method of making such member. The member has a body ( 12 ) provided as a preform of a curable elastomeric polymeric material. A radio frequency identification (RFID) transponder ( 50 ) is inserted into the preform. The preform is then cured to form the body and to embed the RFID transponder ( 50 ) therein.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates broadly to the use of radio frequency identification (RFID) transponders which are embedded into an elastomeric fluid seal member for purposes of tracking or otherwise identifying the member or details thereof. 
         [0002]    RFID and other identification and tracking methods and devices are shown, for example, in U.S. Pat. Nos. 7,398,692; 7,158,034; and 7,0678,170, and in U.S. Pat. Appln. Pub. Nos. US2003/0160391 and 2008/0258401. 
         [0003]    Fluid seals, also known as packings or gaskets, for machine and other part joints are well-known in the art. Typical applications therefor involves the provision of a fluid seal intermediate relatively movable, i.e., dynamic, or fixed, i.e., static, surfaces. Such seals conventionally are configured as a ring or other closed geometric shape, or as a strip or other length, which is molded or otherwise formed of a resilient material such as an elastomeric polymeric material which may be a natural or synthetic rubber. 
         [0004]    Ideally, fluid seal members of the type herein involved should provide effective sealing under static and dynamic conditions, at both low and high pressures, and with a minimum of static and dynamic friction for a long, maintenance-free service life. As the demands placed on seals continue to increase, it is believed that further improvements in the functionality thereof would be well-received by various industries. 
       BROAD STATEMENT OF THE INVENTION 
       [0005]    The present invention is directed to the use of radio frequency identification (RFID) transponders which are molded or otherwise embedded into the body of an elastomeric fluid seal member. The member which is so tagged with the RFID transponder may be in the configuration of an o-ring, sanitary gasket, or other shape or length. 
         [0000]    For assembly, inventory control, and/or maintenance by the manufacturer, stocking distributor, and/or end user, the transponder may be programmed with information specific to the seal such as its part, serial, batch and/or lot number, material code, dimensions, date of manufacture, sale, installation, and/or expiration date. The transponder also may be programmed with a unique identifier or code which may be cross-referenced to an electronic database or other compilation of such information. 
         [0006]    In the manufacture of the RFID-tagged seal of the present invention, one or more RFID transponders are embedded into the body the seal. In this regard, the body initially may be provided as a ring or other closed or open geometric shape or length of a preform which itself is injection or compression molded, extruded, or otherwise formed of a “green,” i.e., unvulcanized or otherwise uncured or partially cured, elastomeric polymeric material such as a natural or synthetic rubber. The RFID transponder, which may be in the form of a tag or similar device, then may be inserted into the cross-section of the preform. The preform with the RFID tag so inserted then may be subjected to conventional processing such as heated compression or other molding to cure the preform and thereby form the body of the seal with the RFID transponder embedded therein. Advantageously, in such method the RFID transponder may be generally centered in the seal relative to the central horizontal and/or vertical axes of the body cross-section. In this way, the transponder may be entirely encased within the seal body so as to not interfere with the proper functioning of the seal when placed in service. 
         [0007]    The present invention, accordingly, comprises the construction, combination of elements, and/or arrangement of parts and steps which are exemplified in the detailed disclosure to follow. Advantages of the present invention include a seal having an integrated RFID transponder for tracking, monitoring, and otherwise identifying the seal. These and other advantages will be readily apparent to those skilled in the art based upon the disclosure contained herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein: 
           [0009]      FIG. 1  is a perspective view of an illustrative embodiment of an RFID-tagged fluid seal member according to the present invention, such member being depicted as having the general shape of an o-ring; 
           [0010]      FIG. 2  is a top view of the fluid seal member of  FIG. 1 ; 
           [0011]      FIG. 3  is a radial cross-sectional view of the fluid seal member of  FIG. 2  taken through line  3 - 3  of  FIG. 2 ; 
           [0012]      FIG. 4  is a top cut-away view of a representative RFID transponder for implantation into the RFID-tagged fluid seal of the present invention; 
           [0013]      FIG. 5  is a top view of an alternative embodiment of a fluid seal member according to the present invention, such member being depicted as having the general shape of a sanitary gasket; and 
           [0014]      FIG. 6  is a radial cross-sectional view of the fluid seal member of  FIG. 5  taken through line  6 - 6  of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Certain terminology may be employed in the following description for convenience rather than for any limiting purpose. For example, the terms “forward” and “rearward,” “front” and “rear,” “right” and “left,” “upper” and “lower,” and “top” and “bottom” designate directions in the drawings to which reference is made, with the terms “inward,” “inner,” “interior,” or “inboard” and “outward,” “outer,” “exterior,” or “outboard” referring, respectively, to directions toward and away from the center of the referenced element, the terms “radial” or “horizontal” and “axial” or “vertical” referring, respectively, to directions or planes which are perpendicular, in the case of radial or horizontal, or parallel, in the case of axial or vertical, to the longitudinal central axis of the referenced element, and the terms “downstream” and “upstream” referring, respectively, to directions in and opposite that of fluid flow. Terminology of similar import other than the words specifically mentioned above likewise is to be considered as being used for purposes of convenience rather than in any limiting sense. 
         [0016]    In the figures, elements having an alphanumeric designation may be referenced herein collectively or in the alternative, as will be apparent from context, by the numeric portion of the designation only. Further, the constituent parts of various elements in the figures may be designated with separate reference numerals which shall be understood to refer to that constituent part of the element and not the element as a whole. General references, along with references to spaces, surfaces, dimensions, and extents, may be designated with arrows. Angles may be designated as “included” as measured relative to surfaces or axes of an element and as defining a space bounded internally within such element therebetween, or otherwise without such designation as being measured relative to surfaces or axes of an element and as defining a space bounded externally by or outside of such element therebetween. Generally, the measures of the angles stated are as determined relative to a common axis, which axis may be transposed in the figures for purposes of convenience in projecting the vertex of an angle defined between the axis and a surface which otherwise does not extend to the axis. The term “axis” may refer to a line or to a transverse plane through such line as will be apparent from context. 
         [0017]    For illustrative purposes, the precepts of the RFID-tagged fluid seal of the invention herein involved are described principally in connection with its configuration as an o-ring or as a sanitary gasket having a generally circular circumference. Such seals are used for a variety of fluid, i.e., liquid, gas, particulate solids, and/or plasmas, sealing applications. In view of the discourse to follow, however, it will be appreciated that aspects of the present invention may find utility in other seal configurations having circumferences or perimeters of other regular or irregular geometries, or in linear or rectilinear, or curvilinear or otherwise actuate open geometries such as strips or other lengths. Use within those such other shapes and lengths therefore should be considered to be expressly within the scope of the present invention. 
         [0018]    Referring then to the figures wherein corresponding reference characters are used to designate corresponding elements throughout the several views with equivalent elements being referenced with prime or sequential alphanumeric designations, a representative o-ring according to the present invention is shown generally at  10  in the perspective view of  FIG. 1  and the top view of  FIG. 2 . In the unstressed or free state of the seal ring  10  which is depicted in  FIGS. 1 and 2 , the seal ring  10  has a body,  12 , which extends around a longitudinal axis,  14 , in defining a generally circular circumference. As may be seen best with additional reference to the radial cross-sectional view of  FIG. 3 , body  12  may have a generally circular profile which is centered relative to a vertical seal axis,  20 , disposed generally parallel to longitudinal axis  14 , and a horizontal seal axis,  22 , disposed orthogonally to the vertical axis  20 . Although the profile of seal body  12  is shown in  FIG. 3  to be circular, such profile alternatively may be semicircular, i.e., D-shaped, elliptical, or otherwise actuate, polygonal, i.e., square, rectangular, or trapezoidal, lobed, i.e., X- or M-shaped, or other regular or irregular geometric shape. Depending on such shape, seal ring  10  may present in service upper and lower,  30  and  32 , and inner and outer diameter,  34  and  36 , sealing faces such as when compressed intermediate relatively movable, i.e., dynamic, or fixed, i.e., static, mating machine parts, hardware, or other surfaces. 
         [0019]    The body  12  of seal ring  10  may be conventionally molded, extruded and cut, or otherwise formed of an elastomeric material which specifically may be selected for low or high temperature performance, flexibility, or otherwise for compatibility with the fluid being handled. Suitable materials, which may be filled, for example, with glass or carbon black, or which may be unfilled, include natural rubbers such as Hevea and thermoplastic, i.e., melt-processible, or thermosetting, i.e., vulcanizable, synthetic rubbers such as: fluoro- or perfluoroelastomers, chlorosulfonate, polybutadiene, butyl, neoprene, nitrile, polyisoprene, buna-N, copolymer rubbers such as ethylene-propylene (EPR), ethylene-propylene-diene monomer (EPDM), acrylonitrile-butadiene (NBR or HNBR) and styrene-butadiene (SBR), and blends such as ethylene or propylene-EPDM, EPR, or NBR. The term “synthetic rubbers” also should be understood to encompass materials which alternatively may be classified broadly as thermoplastic or thermosetting elastomers such as polyurethanes, silicones, fluorosilicones, styrene-isoprene-styrene (SIS), and styrene-butadiene-styrene (SBS), as well as other polymers which exhibit rubber-like properties such as plasticized nylons, polyolefins, polyesters, ethylene vinyl acetates, fluoropolymers, and polyvinyl chloride. As used herein, the term “elastomeric” is ascribed its conventional meaning of exhibiting rubber-like properties of compliancy, resiliency or compression deflection, low compression set, flexibility, and an ability to recover after deformation, i.e., stress relaxation. 
         [0020]    With reference again to the top and cross-sectional views of  FIGS. 2 and 3 , one or more RFID transponders, one of which is shown in phantom at  50  in  FIG. 1 , are embedded in the cross-section of the body  12 . With momentary reference to the cut-away view of  FIG. 4 , transponder  50  may be provided as a passive tag or similar device including a onboard chip,  52 , which may function both as a radio receiver and transmitter, as well as an electronic data storage medium, and tuned conductor,  54 , which acts as an antenna. As it may be so provided, such transponder  50  requires neither an internal power source which would need replacement, nor an external power source or other component which would require hardwire or other connections extending out of the body  12  that could interfere with the sealing function of the seal ring  10 . Transponder  50  thus may be completely encapsulated within the seal body  12  and thereafter need not be removed therefrom. 
         [0021]    It will be appreciated that as may be configured as shown as having generally linear dimensions, the precise length or longer dimension of the transponder  50  and the thickness thereof will determine, respectively, the minimum radius of curvature and radial cross-sectional thickness of the seal ring  10 . Such minimums are necessary to provide a sufficient sealing thickness of the elastomeric material of the seal body  12 , and otherwise to entirely embed the transponder  50  within the seal body  12  such that no part of the transponder  50  protrudes out of the body  12 . In this regard, the use of smaller RFID tags will be understood to allow for the use of a smaller seal body  12 . Alternately, larger diameter or cross-section seals, or those having a circumference or perimeter with a linear section, will allow for the use of a longer and/or thicker RFID tags which may include a bigger antenna for increased signal range. 
         [0022]    Returning now to  FIGS. 2 and 3 , in the manufacture of seal ring  10 , seal body  12  initially is supplied as a ring of a preform, commonly referenced with body  12  at  12 ′, having substantially the same nominal dimensions. The preform  12 ′ may be injection or compression molded, extruded, or otherwise formed of a “green,” i.e., unvulcanized or otherwise uncured or partially cured, form-stable, generally viscoelastic mass of elastomeric polymeric material such as a natural or synthetic rubber. With the preform  12 ′ being so provided in such uncured state, RFID transponder  50  thus may be inserted into the cross-section of the preform, such as through one of the faces  30 ,  32 ,  34 , or  36  thereof as is shown in phantom at  50 ′ in  FIG. 2 . 
         [0023]    As may be seen best in  FIG. 3 , such insertion may center the transponder  50  in the cross-section of the body  12  relative to the relative to the vertical seal axis  20  and/or the horizontal seal axis  22 . Such centering serves to protect the transponder  50  during subsequent processing of the preform  12 ′ and to provide reliable sealing functions in the finished seal ring  10 . Moreover, by so centering the transponder  50 , compressive loads imposed on the sign ring  10  in service may be better distributed to protect the transponder  50  from damage. Also, the transponder  50  may be better protected from high or low temperature extremes by the inherent insulation of the rubber material forming the body  12 . The insertion of the transponder  50  into the preform  12 ′ may be performed manually or, alternatively, with the assistance of a jig or guide and/or under automated control. 
         [0024]    Multiple transponders  50 , as shown at  50   a - f , may be so implanted into preform  12 ′. By implanting multiple transponders  50  as a grouping in a defined segment of the circumference of the preform  12 ′, such as is shown for the transponders  50   a - c , the information storage capacity of the seal ring  10  may be increased. Alternatively, by distributing the transponders  50  along the circumference of the preform  12 ′, such as is shown for the transponders  50   d - f , the seal ring  10  may be “read” from different locations along its circumference which may be desirable in the case of a large diameter seal ring  10  or one which is installed in a hard-to-reach location. For larger diameter seals, a color or other marking may be applied to the outer surface thereof to identify the locations of the one or more transponders  50 . 
         [0025]    Following the insertion of the one or more RFID transponders  50  into preform  12 ′ in the manner so described, preform  12 ′ thereupon may be subjected to conventional processing, such as heated compression or other molding, to cure the preform  12 ′ and thereby form the body of the seal with the RFID transponder embedded therein. By “cured” it is meant that the material of the preform  12 ′ may be polymerized, cross-linked, further cross-linked or polymerized, vulcanized, cooled, hardened, or otherwise chemically or physically changed from its form-stable viscoelastic state into a solid or more-solid elastomeric state or form. Advantageously, the transponder  50  has observed to not substantially migrate within the preform  12 ′ during subsequent processing such that it may remain centered within the finished seal body  12 . 
         [0026]    Following such processing, the transponder  50  may be encoded or otherwise programmed with information specific to the seal ring  10  such as its part, serial, batch and/or lot number, material code, dimensions, date of manufacture, sale, installation, and/or expiration date. Transponder  50  also may be programmed with a unique identifier or code which may be cross-referenced to an electronic database or other compilation of such information. With transponder  50  so programmed, it may be queried with an associated reader (not shown) which likewise may be programmed to store and interpret the data received from the transponder  50 . Such data may be used by a manufacturer, stocking distributor, and/or end user before or after the seal ring is put into service, such as for assembly, inventory control, and/or maintenance purposes. For example, seal ring  10  may be identified using the reader without the need for supporting documentation such as a label or packaging. The ring  10  also may be linked via the reader to application, service, or other information provided by the manufacturer. 
         [0027]    Within a warehouse environment, the ring  10  if misplaced may be identified and re-labeled rather than discarded. An assembly, maintenance, or repair person can verify the part number of the ring  10  prior to installation or replacement and, if the design of the mating parts permits, that the correct ring  10  has been installed after the assembly or what kind of ring  10  needs replacement prior to disassembly. Each of these situations represents a significant cost savings in terms of avoiding stock losses, assembly errors, and maintenance down time. 
         [0028]    In service, seal ring  10  may be compressed by between about 10-30%, such as mounted in an associated groove or gland, or otherwise intermediate relatively movable, i.e., dynamic, or fixed, i.e., static, mating machine parts, hardware, or other surfaces, to provide a fluid seal between the surfaces which themselves may be formed of metal or plastic. It should be appreciated that the ability to read the transponder  50  in situ will depend on various factors, although it is believed that in many applications the signal from the reader may be transmitted through the seal, energize the transponder  50 , and then be transmitted back as a return signal without undue attenuation. This is particularly so in the case of sanitary gasket applications in which the mating hardware does not fully encase the gasket. 
         [0029]    Looking lastly to  FIG. 5 , an another illustrative RFID-tagged fluid seal in accordance with the present invention is shown generally at  100  as configured as a sanitary gasket such as commonly used in the pharmaceutical, food and beverage, and cosmetics industries. In general shape, gasket  100  has a body,  102 , which extends around a longitudinal axis,  104 , in defining a generally circular circumference. As may be seen best with additional reference to the radial cross-sectional view of  FIG. 6 , body  102  may have a generally rectangular profile which again is centered relative to a vertical seal axis,  106 , disposed generally parallel to longitudinal axis  146 , and a horizontal seal axis,  108 , disposed orthogonally to the vertical axis  106 . In the embodiment shown, gasket  100  has upper and lower sealing faces,  110   a - b , which are configured in the form of generally hemispherical lobes. Such lobes may be provided to be received to seat the gasket within corresponding grooves formed into the surface of the mating parts (not shown) between which the gasket  100  may be mounted. In other respects, gasket  100  is similar to seal ring  10  of the preceding figures in structure and use, with one or more RFID transponders, one of which is referenced at  120 , being embedded in body  102  as again centered with respect to the axes  106  and  108 . 
         [0030]    It is anticipated that certain changes may be made in the present invention without departing from the precepts herein involved. Accordingly, the foregoing description should be interpreted as illustrative and not in a limiting sense. All references including any priority documents cited herein are expressly incorporated by reference.