Abstract:
A conduit fitting for a hazardous environment includes a main body that has a distal portion and a proximate portion. The main body includes a longitudinal bore with openings at each of the distal portion and the proximate portion. The opening is configured to receive ends of a conduit. The fitting includes a first sealing region that includes a crimp feature configured to be crimped and a second sealing region adjacent the first sealing region. The second sealing region is configured to house a sealing component.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of provisional application Ser. No. 62/368,611, filed Jul. 29, 2016, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    When installing electrical components in hazardous environments, particular precautions must be taken to ensure a safe work environment. Hazardous environments are environments that may include ignitable or combustible gas, vapor, dust, or fiber. Due to the potential ignition risk of any electrical components within the hazardous environment, conduits are often used to protect and isolate such components within the environment. Because of this, conduit and conduit connections need to be sealed from the hazardous environment to reduce the potential for a fire or explosion. Specifically, the Standard “UL 1203,” along with other standards, set forth criteria for explosion proof electrical equipment for use in hazardous environments such as requiring mating surfaces to utilize threaded joints, controlled flat or labyrinth joints, or cemented or bonded joints. However, the conduit that is used is often imperfect as it is commonly extruded or welded tubing that is not a high tolerance part. Dimensional variation along the length and perimeter of the conduit are common and such defects affect the ability for the conduit to comply with flame-path requirements. Often, threaded joints are commonly used due to the round shape of the conduit and the proven effectiveness of a threaded joint. However, creating a sealed conduit connection can be cumbersome and time consuming. Therefore, improvements in sealing conduit connections are needed, particularly in field-created joining methods for improvements in system safety, reliability, and installation time. 
       SUMMARY 
       [0003]    The present disclosure relates generally to sealing conduit connections within hazardous environments in the field. In one possible configuration, and by non-limiting example, sealing is accomplished by using a fitting with at least one crimp region and at least one sealant medium. 
         [0004]    In a first aspect of the present disclosure, a conduit fitting is disclosed. The conduit fitting for a hazardous environment includes a main body that has a distal portion and a proximate portion. The main body includes a longitudinal bore with openings at each of the distal portion and the proximate portion. The opening is configured to receive ends of conduit. The fitting includes a first sealing region that includes a crimp feature configured to be crimped and a second sealing region adjacent the first sealing region. The second sealing region is configured to house a sealing component. In some examples, the first and second sealing regions are configured to create an explosion proof seal around an end of the conduit. 
         [0005]    In a second aspect of the present disclosure, a method of securing a fitting to a conduit portion in a hazardous environment is disclosed. The method includes providing a fitting that includes a main body that has a distal end and a proximate end. The main body includes a longitudinal bore with openings at each of the distal end and the proximate end, and the openings are configured to receive ends of the conduit. The fitting also includes a first sealing region and a second sealing region adjacent the first sealing region. The method includes inserting a first end of the conduit into an opening of the main body of the fitting and providing a sealing component between the fitting and the conduit at the second sealing region. The method also includes crimping the first sealing region around the conduit and providing an explosion proof seal between the fitting and the conduit. 
         [0006]    A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The following drawings are illustrative of particular embodiments of the present disclosure and therefore do not limit the scope of the present disclosure. The drawings are not to scale and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the present disclosure will hereinafter be described in conjunction with the appended drawings, wherein like numerals denote like elements. 
           [0008]      FIG. 1  illustrates a side view of a hazardous environment conduit fitting, according to one embodiment of the present disclosure; 
           [0009]      FIG. 2  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and a pressure sensitive adhesive, according to one embodiment of the present disclosure; 
           [0010]      FIG. 3  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and an injectable sealant, according to one embodiment of the present disclosure; 
           [0011]      FIG. 4  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and a microcapsule matrix seal, according to one embodiment of the present disclosure; 
           [0012]      FIG. 5  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and an expanding heat activated seal, according to one embodiment of the present disclosure; 
           [0013]      FIG. 6  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and a chambered seal, according to one embodiment of the present disclosure; 
           [0014]      FIG. 7  illustrates a front view of the chambered seal of  FIG. 6 ; 
           [0015]      FIG. 8  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and a helical flame path, according to one embodiment of the present disclosure; 
           [0016]      FIG. 9  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and a labyrinth flame path, according to one embodiment of the present disclosure; and 
           [0017]      FIG. 10  illustrates a side view of a conduit connection utilizing the conduit fitting of  FIG. 1  and a sealant adaptor, according to one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. 
         [0019]    The sealing solutions disclosed herein have several advantages. Specifically, the sealing solutions do not require that the ends of conduit be threaded for connection with a threaded joint in a hazardous environment. This is advantageous as the sealing solutions described herein can be completed in less time by the installer and can also be performed in a smaller space. Further, the sealing solutions described herein create an explosion proof conduit connection that meets UL 1203 and/or CSA 22.2 #30 is yet another example. In some examples, the sealing solutions described herein create an explosion proof conduit connection by one of a pressure sensitive adhesive, a flowable epoxy, a heat activated thermoplastic, a two component epoxy, a flame-path, or a pressure activated epoxy. In other examples, the sealing solutions described herein create a conduit connection that can be used in a variety of environments, and not necessary just hazardous environments. In some examples, the sealing solutions described herein create a conduit connection that is a sealed connection and not explosion proof. 
         [0020]      FIG. 1  shows a conduit fitting  100  connecting a first conduit end  102  and a second conduit end  104  forming a conduit connection. The fitting  100  is configured to form an explosion proof conduit connection for use in a hazardous environment. The fitting  100  includes a central bore  101 , a first end  106  and a second end  108 . In the depicted embodiment, a cutaway of the first end  106  is shown for illustration purposes. 
         [0021]    The central bore  101  continues longitudinally through the fitting  100  from the first end  106  to the second end  108 . In some embodiments, the central bore  101  can be stepped to accommodate a plurality of different sealing configurations. Further, the central bore  101 , and fitting  100  in general, can be sized to accommodate a wide range of conduit sizes that are commonly used within hazardous environments. In some embodiments, the diameter of the central bore is about, but not limited to, 0.5 to 6.0 inches. 
         [0022]    The first end  106  includes a first region  110  and a second region  112 . The first and second regions  110 ,  112  are configured to receive heat treatment or compression force by a crimping wrench (not shown). In the depicted embodiment, the first end  106  optionally includes an O-ring  113  positioned within the fitting  100  between the first and second regions  110 ,  112 . 
         [0023]    The second end  108  includes a third region  114  and a fourth region  116 . The third and fourth regions are substantially similar to the first and second regions  110 ,  112  and are also configured to receive heat treatment or compression force. In some embodiments, the second end  108  is substantially identical to the first end  106 . In some embodiments, the second end  108  also includes an O-ring (not shown) positioned within the fitting  100  between the third and fourth regions  114 ,  116 . 
         [0024]    In some embodiments, at a region  115  generally between the first and second ends  106 ,  108  an internal bushing  117  may be located in the central bore  101 . The internal bushing  117  can function as a positive stop for the conduit and generally has an inner diameter smaller than that of the central bore  101  of the fitting  100  and the conduit. 
         [0025]    In the cutaway region at the first end  106 , the first conduit end  102  is shown positioned within the central bore  101  of the fitting  100 . Specifically, the first conduit end  102  is positioned and aligned with the first and second regions  110 ,  112 . 
         [0026]    The first region  110  is shown to include crimping features  118  that are configured to engage the first conduit end  102  when a force is applied at the first region by a crimping tool. In the depicted embodiment, the crimping features  118  are a plurality of teeth positioned on the interior portion of the fitting  100  at the first region  110 . The teeth will bite into the first conduit end  102  when the first region  110  is compressed. The crimping features  118  can help aid in axial retention of the first conduit end  102  within the fitting  100 , and in maintaining a ground connection. 
         [0027]    The second region  112  is shown to include a void  120  between the central bore  101  and the first conduit end  102 . The void  120  is configured to receive a plurality of different sealing components, as described herein. In some embodiments, the second region  112  can also include a crimp feature similar the crimp feature  118  of the first region  110 . 
         [0028]      FIG. 2  shows the fitting  100  and a sealing solution according to one embodiment of the present disclosure. In the depicted embodiment, the void  120  between the second region  112  and the first conduit end  102  includes a pressure sensitive adhesive (“PSA”)  122 . The PSA  122  fills the void  120  completely to form a seal between the central bore  101 , specifically at the second region  112 , and the first conduit end  102 , thereby forming a cemented joint between the fitting  100  and the first conduit end  102 . In some embodiments, the second conduit end  104  can be sealed with the fitting  100  in a substantially similar manner as the first conduit end  102 . 
         [0029]    The PSA  122  can be a continuous flexible strip of cloth, paper, metal, plastic, or foam that is coated on one or both sides with an adhesive. The PSA  122  is configured to adhere to the first conduit end  102  and/or central bore  101  of the fitting  100  with pressure. In some embodiments, the PSA  122  can be a blend of natural or synthetic rubber and resin, acrylic, silicone, or other polymer, with or without additives. 
         [0030]    In some embodiments, the PSA  122  is installed into the central bore  101  of the fitting  100  prior to inserting the first conduit end  102  into the fitting  100 . In other embodiments, the PSA  122  is wrapped around the first conduit end  102  prior to inserting the first conduit end  102  into the fitting  100 . A first crimping force  124  and a second crimping force  126  are then exerted by the installer at both the first and second regions  110 ,  112 , respectively. The first crimping force  124  compresses the fitting  100  and engages the crimping features  118  with the first conduit end  102 . The second crimping force  126  compresses the fitting  100  around the PSA  122 , sandwiching the PSA  122  between the central bore  101  of the fitting  100  and the first conduit end  102  to create a cemented joint for a hazardous environment. The PSA  122  allows the installer to quickly seal the conduit connection, while using a relatively low cost sealant. 
         [0031]      FIG. 3  shows the fitting  100  and a sealing solution according to one embodiment of the present disclosure. In the depicted embodiment, the void  120  between the second region  112  and the first conduit end  102  includes an injectable sealant  222 . Like the PSA  122 , the injectable sealant  222  fills the void  120  completely to form a cemented seal between the central bore  101  and first conduit end  102 , specifically at the second region  112 . In some embodiments, the second conduit end  104  can be sealed with the fitting  100  in a substantially similar manner as the first conduit end  102 . 
         [0032]    In the depicted embodiment, the fitting  100  includes an injection port  228  to allow the injectable sealant  222  to be inserted from the outside of the fitting  100  into the void  120 . In some embodiments, the fitting  100  can also include a weep port  230  that permits the installer to visibly see when the void  120  has been completely filled with sealant. In some embodiments, the weep port  230  is positioned at the opposite side of the fitting  100  from the injection port  228 . 
         [0033]    The injectable sealant  222  can be a flowable epoxy of a variety of different types. For example, the injectable sealant  222  can be a two-part epoxy (also referred to as “two component epoxy” or “2K epoxy”) that the installer can mix on site. In other examples, the injectable sealant  222  is a polyurethane substance that expands to sealant foam. In some embodiments, the injectable sealant  222  can at least partially cure very quickly, offering the installer a cemented joint in a short amount of time. 
         [0034]    In some embodiments, the injectable sealant  222  is injected into the central bore  101  of the fitting  100  via the injection port  228  after inserting the first conduit end  102  has been positioned in the fitting  100 . After injecting a set amount of sealant, or receiving confirmation from the weep port  230  that enough sealant has been injected, the installer applies a first crimping force  224  at the first region  110 . In some embodiments, the installer may also treat the second region  112  with heat to increase the curing speed of the injectable sealant  222 . Once cured, the injectable sealant  222  fills the void  120  between the central bore  101  of the fitting  100  and the first conduit end  102  to create a cemented joint for a hazardous environment. The injectable sealant  222  allows the installer to quickly seal the conduit connection, while using a relatively low cost sealant. 
         [0035]      FIG. 4  shows the fitting  100  and a sealing solution according to one embodiment of the present disclosure. In the depicted embodiment, the void  120  between the second region  112  and the first conduit end  102  includes a pressure activated microcapsule matrix  322 . The microcapsule matrix  322  fills the void  120  completely to form a seal between the central bore  101  and the first conduit end  102 , specifically at the second region  112 . The microcapsule matrix  322  forms a cemented joint between the fitting  100  and the first conduit end  102 . In some embodiments, the second conduit end  104  can be sealed with the fitting  100  in a substantially similar manner as the first conduit end  102 . 
         [0036]    The microcapsule matrix  322  can be positioned within the central bore  101  of fitting  100  and can be dry and non-tacky to the touch. The microcapsule matrix  322  comprises a dried first substance and a plurality of material-filled microcapsules. Applying pressure ruptures the microcapsules causing the material contained within to be released. Once such material mixes with either the dried first substance of other encapsulated materials, the matrix  322  becomes a wet, flowable adhesive. In one embodiment, the microcapsule matrix  322  can be a foaming polyurethane or an epoxy. 
         [0037]    In some embodiments, the microcapsule matrix  322  is installed into the central bore  101  of the fitting  100  when the fitting  100  is manufactured, prior to the fitting reaching the installer. In other embodiments, the installer can treat the fitting  100  or the first conduit end  102  at the site with the microcapsule matrix  322  in the form of a spray, tape, or similar coating. A first crimping force  324  and a second crimping force  326  are then exerted by the installer at both the first and second regions  110 ,  112 , respectively. In some embodiments, the first and second crimping forces may be exerted at both the first and second regions  110 ,  112  at the same time by either a single tool or multiple tools. Similar to above, the first crimping force  324  compresses the fitting  100  and engages the crimping features  118  with the first conduit end  102 , and the second crimping force  326  compresses the fitting  100  around the microcapsule matrix  322 . Such compression breaks the microcapsules within the matrix  322 , and allows the matrix  322  to create seal that creates a cemented joint for a hazardous environment. The microcapsule matrix  322  allows the installer to quickly seal the conduit connection. 
         [0038]      FIG. 5  shows the fitting  100  and a sealing solution according to one embodiment of the present disclosure. In the depicted embodiment, the void  120  between the second region  112  and the first conduit end  102  includes an expanding heat activated seal  422 . Similar to above, the heat activated seal  422  fills the void  120  completely to seal the central bore  101 , specifically at the second region  112 , forming a cemented joint between the fitting  100  and the first conduit end  102 . In some embodiments, the second conduit end  104  can be sealed with the fitting  100  in a substantially similar manner as the first conduit end  102 . 
         [0039]    The heat activated seal  422  can be positioned within the central bore  101  of fitting  100 , either from the factory or installed within the fitting  100  by the installer, similar to the PSA  122  and microcapsule matrix  322 . The heat activated seal  422  can be a thermoplastic matrix that is voided to entrap gas. When heat is applied, the gas expands and also expands the seal  422 . 
         [0040]    Once the heat activated seal  422  positioned within the fitting  100  at the second region  112 , and the first conduit end  102  is inserted into the fitting  100 , a first crimping force  424  is exerted by the installer at the first region  110 . Similar to above, the first crimping force  424  compresses the fitting  100  and engages the crimping features  118  with the first conduit end  102 . A localized controlled heat source  426  (e.g., from a resistive heater) is then applied at the second region  112  to activate the seal  422 . In some embodiments, after heat is applied, the second region can then also be cooled to solidify the seal  422  faster. Once solid, the heat activated seal  422  creates a cemented joint for a hazardous environment. The heat activated seal  422  allows the installer to quickly seal the conduit connection and is also rugged and chemical resistant. 
         [0041]      FIG. 6  shows the fitting  100  and a sealing solution according to one embodiment of the present disclosure. In the depicted embodiment, the void  120  between the second region  112  and the first conduit end  102  includes a chambered seal  522 . The chambered seal  522  fills the void  120  completely to form a seal between the central bore  101  and the fitting  100 , specifically at the second region  112 , forming a cemented joint between the fitting  100  and the first conduit end  102 . In some embodiments, the second conduit end  104  can be sealed with the fitting  100  in a substantially similar manner as the first conduit end  102 . 
         [0042]    The chambered seal  522  can be positioned within the central bore  101  at the second region  112  of fitting  100 , either from the factory or installed within the fitting  100  by the installer. The chambered seal  522  includes a first component  528  and a second component  530 , each individually sealed from one another in separate chambers  532 . The components  528 ,  530  can be similar to the components that make up the injectable sealant  222  and can form a two component, or  2   k , epoxy when mixed with one another. When the first and second components  528 ,  530  are mixed with one another, they create a flowable epoxy that expands in volume, and fills the void  120  and creates a seal around the first conduit end  102 . To mix the components  528 ,  530  together, the chambered seal  522  can include a rip cord (not shown) or similar feature that allows the components  528 , 530  to mix. In some embodiments, the central bore  101  of the fitting  100  includes a feature to break open the chambered seal  522  such as knives or blades. In some embodiments, the chambers  532  are broken by spinning either the fitting  100  or the first conduit end  102  about each other. In some embodiments, the fitting  100  includes a weep port, similar to the weep port  230 , to allow the installer to know when the void  120  has been completely filled by the seal  522 . 
         [0043]    Once the chambered seal  522  is positioned within the fitting  100  at the second region  112  and the first conduit end  102  is inserted into the fitting  100 , a first crimping force  524  is exerted by the installer at the first region  110 . Similar to above, the first crimping force  524  compresses the fitting  100  and engages the crimping features  118  with the first conduit end  102 . The installer then breaks the chambers  532  of the chambered seal  522  to mix the components  528 ,  530 . In some embodiments, the installer can then check a weep port to ensure that the chambered seal  522  has created a seal between the fitting  100  and the first conduit end  102 . Like the seals described above, once cured, the chambered seal  522  creates a cemented joint for a hazardous environment that allows the installer to quickly seal the conduit connection and is also rugged and chemical resistant. 
         [0044]      FIG. 8  shows the fitting  100  and a sealing solution according to one embodiment of the present disclosure. In the depicted embodiment, the void  120  between the second region  112  and the first conduit end  102  includes a first flame path  622 , or, as shown in  FIG. 9 , a second flame path  722 . The first and second flame path  622 ,  722  operate in a similar manner and will be discussed herein concurrently. The flame paths  622 ,  722  can be created within the fitting by exerting a compression force at the second region  112  of the fitting  100 . The flame paths  622 ,  722  create an explosion-proof joint between the first conduit end  102  and the fitting  100 . In some embodiments, the second conduit end  104  can be sealed with the fitting  100  in a substantially similar manner as the first conduit end  102 . 
         [0045]    The flame paths  622 ,  722  provide a path for explosion gasses to the escape the conduit and fitting  100 . By creating a varied path for the gas to travel, the gas from any explosion that occurs within the fitting  100  or conduit is cooled and allowed to leave the fitting. This keeps the hot flaming gas retained within the fitting  100  and conduit, reducing the possibility of a larger explosion in the hazardous environment outside of the conduit and fitting  100 . In  FIG. 8 , the flame path  622  is shown to be helically shaped, similar to a threaded surface. In  FIG. 9 , the flame path  722  is shown to be a labyrinth-shaped flame path. In other embodiments, the flame paths  622 ,  722  can be a cylindrical shape or other shape that allows gasses to cool and escape the conduit connection. In some embodiments, the flame paths can  622 ,  722  can be pre-formed within the fitting  100 . 
         [0046]    During installation, the installer first places the first conduit end  102  into the fitting  100 . Similar to above, a first crimping force  624  compresses the fitting  100  and engages the crimping features  118  with the first conduit end  102 . The installer then creates the flame path  622 ,  722  by exerting a second compression force  626  at the second region  112  of the fitting. The second compression force  626  generates and creates the flame path  622 ,  722 . In some embodiments, the void  120  is only partially closed to allow for a flame path. 
         [0047]    In some examples, a flame path  622 ,  722  can be used in addition to the one or more of sealing solutions described above in connection with  FIGS. 1-7 . For example, the fitting  100  can include a pressure sensitive adhesive, a flowable epoxy, a heat activated thermoplastic, a two component epoxy, and/or a pressure activated epoxy along with a flame path  622 ,  722  within the same fitting  100 . In some examples, the flame path  622 ,  722  and pressure sensitive adhesive, flowable epoxy, heat activated thermoplastic, two component epoxy, and/or a pressure activated epoxy are positioned within the void  120  along with the flame path  622 ,  722 . In other examples still, the sealing solutions described in connection with  FIGS. 1-7  can be used in a system that includes a flame path elsewhere in the system, such as upstream, or downstream from the fitting. In other examples, a series of fittings  100  with different sealing solutions can be used together in a system. For example, a system can include a fitting utilizing a pressure sensitive adhesive, a flowable epoxy, a heat activated thermoplastic, a two component epoxy, and/or a pressure activated epoxy and an additional fitting  100  utilizing a flame path  622 ,  722 . 
         [0048]      FIG. 10  shows the fitting  100  used with a sealing adaptor  800  to seal the inside of the fitting  100  and conduit. As shown, the adapter  800  is mated with the second end  108  of the fitting  100 , opposite of the first end  106  where the first conduit end  102  is inserted into the fitting  100 . In some embodiments, the adapter  800  is press-fit, threaded, or cast into, and as part of, the fitting  100 . As shown, electrical components  802 , such as conductors, are shown positioned within the first conduit end  102 , fitting  100 , and adapter  800 . 
         [0049]    The adapter  800  is configured to allow the installer to apply a flowable sealant  801  into the central bore  101  of the fitting  100  to seal the first conduit end  102  to the fitting  100 , seal the adaptor  800  to the fitting  100 , and seal the conductors  802  to the fitting  100 . The adapter  800  includes a first end  804 , a second end  806 , a first port  808 , and a second port  810 . At the first end  804 , the adapter  800  is attached to the fitting  100 . In some embodiments, the second end  806  of the adapter  800  is connected to an additional fitting or an additional end of a conduit. 
         [0050]    The first port  808  of the adapter  800  is configured to receive the sealant  801  when the adapter is in a generally horizontal positon (as shown). This ensures that the sealant  801  seeps into and coats the fitting  100 , first conduit end  102 , and adaptor  800 . The sealant  801  then also adheres to the conductors  802  and seals them to the fitting  100 . The second port  810  operates in a similar manner as the first port  808 ; however, it is configured to be used when the adaptor  800  is oriented in a more vertical position. 
         [0051]    The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims.