Abstract:
A measuring device for determining the level of material in a container including a process seal comprising: a substantially conical portion including a narrow end and a wide end, the conical portion terminating at the wide end in a substantially cylindrical outer surface; and a flange portion extending outwardly from the substantially cylindrical outer surface. The process seal minimizes reflection and attenuation of measuring device energy, seals the connection to the container, and meets sanitary standards.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field  
           [0002]    The present invention relates generally to process material level measuring, and more particularly to a measuring device and process seal therefor.  
           [0003]    2. Related Art  
           [0004]    Various measuring devices have been used to determine the level of process material in a container such as a tank or vessel. Non-process contact devices may use microwaves or ultrasound. Process seals have been used to sealingly secure the measuring device&#39;s working components to the containers. These process seals generally have two requirements: seal the connection, and do not interfere with device energy transfer into the container.  
           [0005]    U.S. Pat. No. 5,305,237 to Dalrymple et al. discloses a generally conical process lens/seal that requires additional seal members to properly seal. See FIG. 3. This manner of sealing increases the complexity of replacing the process seal. In particular, when the seal is removed, the secondary seals must also be removed and replaced. Another disadvantage of this system is that the various seal surfaces must mate properly to seal, which increases the chances of leakage.  
           [0006]    U.S. Pat. No. 5,262,743 to Jean discloses a process seal having specialized surface grooves for reducing reflection and attenuation of device energy. In the embodiment of FIG. 8, Jean discloses a generally conical process seal. Jean, however, does not disclose the manner in which the process seal seals (i.e., prevents the passing of gas or fluid) the connection/joint.  
           [0007]    The above-described measuring devices have become increasingly more attractive for material level sensing where sanitary conditions are necessary. One such standard that has been promulgated by, among others, the International Association of Food Industry Suppliers (IAFIS) are the “3-A Sanitary Standards for Sensors and Sensor Fittings and Connection Used on Milk and Milk Products Equipment, Number 74-01,” which is hereby incorporated by reference. These standards set out requirements that related art measuring devices and process seals inadequately address.  
           [0008]    In view of the foregoing, there is a need in the art for a measuring device and a process seal therefor capable of sealing connection, minimizing reflection and attenuation of device energy, and sanitary standard compliance.  
         SUMMARY OF THE INVENTION  
         [0009]    In a first aspect of the invention is provided a process seal comprising: a substantially conical portion including a narrow end and a wide end, the substantially conical portion terminating at the wide end in a substantially cylindrical outer surface; and a flange portion extending outwardly from the substantially cylindrical outer surface.  
           [0010]    A second aspect of the invention is directed to a process seal for use with a measuring device coupled to a process material container, the container including a connector, the process seal comprising: a substantially conical portion; a flange portion integrally connected to a periphery of the substantially conical portion, the flange portion having a first side and a second side; and a ridge extending from the first side for mating with a gasket seat of the connector.  
           [0011]    A third aspect of the invention provides a measuring device for connection to an exterior of a process material container, the container having a connector, the measuring device comprising: an electronic measuring system; an adapter coupled to the electronic measuring system; a process seal for sealingly coupling the adapter to the connector, the process seal comprising: a substantially conical portion; a flange portion integrally connected to a periphery of the substantially conical portion, the flange portion having a first side and a second side; and a coupling device for coupling the adapter and the connector together with the flange portion therebetween.  
           [0012]    A fourth aspect of the invention includes a measuring device for connection to an exterior of a process material container, the container having a connector, the measuring device comprising: an electronic measuring system; an adapter coupled to the electronic measuring system; a process seal for sealingly coupling the adapter to the connector, the process seal comprising: a substantially conical portion including a narrow end and a wide end, the substantially conical portion terminating at the wide end in a substantially cylindrical outer surface; a flange portion extending outwardly from the substantially cylindrical outer surface; and a coupling device for coupling the adapter and the connector together with the flange portion therebetween.  
           [0013]    A fifth aspect of the invention is directed to a process seal for use with a measuring device coupled to a process material container, the container including a connector, the process seal comprising: means for minimizing measuring device energy reflection and attenuation; and means, integrally connected to the means for minimizing, for sealing the measuring device to the container.  
           [0014]    A sixth aspect of the invention includes a measuring device for connection to an exterior of a process material container, the container having a connector, the measuring device comprising: means for making a material level measurement; means for directing energy from the means for making a measurement into the container; a process seal including: means for minimizing measuring device energy reflection and attenuation; means, integrally connected to the means for minimizing, for sealing the means for making a measurement to the container; and means for coupling the means for directing and the connector together with the means for sealing therebetween.  
           [0015]    The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    The preferred embodiments of this invention will be described in detail, with reference to the following figures, wherein like designations denote like elements, and wherein:  
         [0017]    [0017]FIG. 1 shows a perspective view of a measuring device in accordance with the invention mounted to a process material container;  
         [0018]    [0018]FIG. 2 shows a perspective view of a process seal;  
         [0019]    [0019]FIG. 3 shows a cross-sectional view of the process seal of FIG. 2;  
         [0020]    [0020]FIG. 4A shows a detail cross-sectional view of the process seal of FIG. 2;  
         [0021]    [0021]FIG. 4B shows a detail cross-sectional view of an alternative embodiment of the process seal of FIG. 1;  
         [0022]    [0022]FIG. 5 shows a perspective view of an adapter for a horn member of the measuring device of FIG. 1;  
         [0023]    [0023]FIG. 6 shows a cross-sectional view of the adapter of FIG. 5;  
         [0024]    FIGS.  7 A-B show a perspective view of various coupling devices; and  
         [0025]    [0025]FIG. 8 shows a cross-sectional view of the measuring device connection to the container. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    Referring to FIG. 1, a perspective view of a measuring device  10  mounted to an exterior of a process material container  12  is shown. Container  12  may contain any manner of material  14  used in any processing. In one example, material  14  is a dairy product such as milk, milk products and culture media. In instances where maintaining a sanitary state is required, container  12  may be constructed of stainless steel such as AISI 300 Series or ACI types, or metal which under conditions of intended use is at least as corrosion resistant as stainless steel, and is nontoxic and nonabsorbent. Container  12  includes a connector  16  for connection with measuring device  10  (see detail in FIG. 8). Connector  16  may be a connection flange or spud, a threaded connection or any other now known or later developed connection member.  
         [0027]    Measuring device  10  generally includes an electronic measuring system  15 , an adapter  62  coupled to electronic measuring system  15 , a process seal (as will be described in more detail below) and a coupling device  24  for connecting system  15  to container  12 . Electronic measuring system  15  may be any now known or later developed microwave or ultrasound measuring device, which are commonly used to test the level of material  14  in container  12 . System  15  includes operational electronic components  17  and a housing  18 . Housing  18  includes a compartment  20  for enclosing electronic components  17  and a horn member  22 .  
         [0028]    Horn member  22  may be provided to direct measuring device energy, e.g., microwaves, into container  12 , and may take a variety of shapes in order to provide this function. For instance, horn member  22  may be substantially cylindrical or, as illustrated, substantially frustoconical. In the case of a frustoconical horn member  22 , the member includes a small end  26  connected to compartment  20  and a large end  28 . It should be recognized that horn member  22  may not always be necessary to the operation of a measuring device  10  such as that discussed herein. In this case, connector  16  may be coupled directly to compartment  20 , or some other intermediate structure.  
         [0029]    Turning to FIGS.  2 - 4 B, a process seal  26  in accordance with an embodiment of the invention is shown. A process seal  26  serves a number of functions. First, it seals the measuring device&#39;s connection to container  12  to prevent material  14  (e.g., a fluid or gas) from escaping and/ or prevent contaminants from entering container  12 . Second, seal  26  passes the measuring device energy (i.e., waves) allowing the energy to pass with minimal attenuation and/or reflection. Third, process seal  26  meets or exceeds sanitary standards that are based on such things as the temperature, pressure, chemical assault of the process material, and geometry to ensure clean-ability. With regard to chemical assault, process seal  26  allows the overall connection to meet or exceed the “3-A Sanitary Standards for Sensors and Sensor Fittings and Connection Used on Milk and Milk Products Equipment, Number 74-01,” as promulgated by, among others, the International Association of Food Industry Suppliers (IAFIS) and accepted by the U.S. Food and Drug Administration (FDA). Exemplary requirements of these standards are that connector material has a pore size less than 0.20 μm (micrometers), can withstand sterilization by saturated steam or water under pressure (at least 15.3 psig or 106 kPa) and a temperature of at least 250° F. (121° C.). In one embodiment, process seal  26  is made of a polytetrofluroethylene (PTFE) material exhibiting the above characteristics. In addition, process seal  26  material also preferably exhibits a low dielectric constant.  
         [0030]    As shown in FIGS. 2 and 3, process seal  26  includes a substantially conical portion  40  and a gasket, flange portion  42 . As shown in FIG. 3, substantially conical portion  40  includes an externally, substantially conical side  44  for facing into container  12  or connector  16 , and an inwardly, substantially conical side  46  for facing towards housing  18 . The substantially conical sides  44 ,  46  are angled as to, at the very least, allow device energy (i.e., waves) to pass with minimal attenuation and/or reflection. Substantially conical portion  40  also includes a narrow end  43  and a wide end  45 . As shown in FIGS. 3 and 4A-B, wide end  45  terminates in a substantially cylindrical outer surface  60 . Flange portion  42  is integrally connected to a periphery  48  of conical portion  40 , and extends outwardly from substantially cylindrical outer surface  60 . As shown in FIG. 4A, flange portion  42  extends outwardly from substantially cylindrical surface  60  adjacent wide end  45 , where substantially conical portion  40  ceases. In an alternative embodiment shown in FIG. 4B, flange  42  may extend outwardly from anywhere along the length of substantially cylindrical surface  60 .  
         [0031]    As further shown in FIGS.  4 A-B, flange portion  42  includes a first side  50  and a second side  52 . First side  50  may include a raised ridge  54  (FIG. 4A) that runs about the surface of first side  50 . As shown in FIG. 8, raised ridge  54  is sized so as to mate with a corresponding gasket seat  56  of connector  16 . Raised ridge  54  and gasket seat  56  are preferably less than approximately one quarter inch height/depth. It should be recognized that where process seal  26  does not require raised ridge  54  and gasket seat  56  to seal, those components may be removed (FIG. 4B). That is, first side  50  is substantially flat, as shown in FIG. 4B.  
         [0032]    With continuing reference to FIGS. 3 and 4A-B, second side  52  of flange portion  42  runs into substantially cylindrical surface  60  of process seal  26 . In combination, surface  60  and second side  52  form a first mating surface  55  for horn member  22  of measuring device  10 . More specifically, in a preferred embodiment, horn member  22  (or whatever portion of housing  18  couples to connector  16 ) includes an adapter  62 , shown in FIGS. 5, 6 and  8  that mates with first mating surface  55 .  
         [0033]    As shown in FIG. 6, adapter  62  includes a housing/horn member connection surface  64  that is welded or otherwise permanently attached to electronic measuring system  15 . That is, adapter  62  is attached to large end  28  of horn member  22 , or, where horn assembly  22  is not provided, compartment  20  or some other intermediate structure. Adapter  62  also includes a first surface  66  that mates with second side  52  of flange portion  42 ; a second surface  68  that mates with substantially cylindrical surface  60  of flange portion  42 ; and a third surface  70  that mates with an end  72  (FIGS. 3 and 8) of process seal  26 . The first surface  66  and second surface  68  form a second mating surface  71  that is substantially complementary to first mating surface  55  of process seal  26 .  
         [0034]    Turning to FIGS.  7 A-B, coupling device  24  for connecting system  15 , adapter  62 , process seal  26  and connector  16  together is shown in more detail. Coupling device  24  may be any type of well known ring clamp such as those available through Tri-Clover® Company. Devices such as coupling device  24  generally include one to three clamping members  76  shaped to compress exterior surfaces of mating components together. Clamping members may be flexible members, pivotally coupled rigid members, or uncoupled rigid members capable of fastening together. Clamping members  76  may be compressed against exterior surfaces of mating components by a toggle device, or one or more threaded fasteners  78 . Other exemplary coupling devices are disclosed in the TriClover® Company brochure, which is hereby incorporated by reference. If a threaded connector  16  is used, coupling device  24  may take a complementary threaded form.  
         [0035]    [0035]FIG. 8 illustrates the overall connection of electronic measuring system  15  to connector  16  and container  12 . Coupling device  24  couples electronic measuring system  15 , via adapter  62 , and connector  16  together with process seal  26  and its flange portion  42  therebetween. More specifically, clamping member(s)  76  engage an exterior clamp surface  80  (FIGS. 5 and 8) of adapter  62  and an exterior clamp surface  82  (FIG. 8) of connector  16 . Flange portion  42  is sized such that compression of adapter  62  and connector  16  together compresses flange portion  42  to seal the connection.  
         [0036]    The above-described measuring device and process seal therefor are capable of sealing connection, minimizing reflection and attenuation of device energy and sanitary standard compliance.  
         [0037]    While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims. For instance, while components of process seal  26 , such as flange portion  42 , have been shown in a circular form, it should be recognized that components may be any shape required.