Abstract:
A swivel fitting is provided for use on a riser line associated with the underground storage tank of gasoline service stations. The swivel fitting includes an adapter sleeve that attaches to the riser line and a swivel sleeve with a quick release fitting for use in removably attaching a product transfer hose as is typically used to transfer product to the underground storage tank from a tanker truck. The adapter and swivel sleeves are rotatably coupled by a plurality of ball bearings to permit smooth rotation of the quick release fitting with respect to the riser line.

Description:
This application is a continuation of Ser. No. 09/236,501 filed Jan. 25 1999. 
    
    
     FIELD OF THE INVENTION 
     This invention is directed to improvements in known swivel fittings for use with riser lines used for transferring petroleum products to underground product storage tanks of the type found at gasoline service stations. The fitting permits a fuel hose to be removably attached to the riser line while permitting rotation of the hose during the transfer of product. 
     BACKGROUND OF THE INVENTION 
     Gasoline service stations typically include a number of underground storage tanks for storing fuel products. A conduit known as a riser line generally extends from the top of each tank to a manhole at the driveway surface of the service station. A drop tube may be concentrically disposed within the riser line, flush with the riser line at the surface but extending beyond the riser line and into the underground storage tank. By removing the manhole cover and a cap from the top of the riser, a hose can be connected to the riser line to fill the product tank with petroleum products delivered by tanker trucks. The hose is generally connected to the riser line using a connector known as a top seal delivery nozzle. Such nozzles allow the hose to be quickly connected and disconnected from the riser line at a fill adapter located on the top of the riser line to simplify product transfer. These fill adapters are typically threaded to the riser line which is in turn threaded into a collar on the top of its respective product tank. When the underground storage tank is not being filled, a removable cap is used to seal the fill adapter both to prevent contaminants from entering the product tank and to prevent hydrocarbon vapors from escaping from the tank. 
     One problem with the use of conventional top seal delivery nozzles is that while no twisting is required to fasten the nozzle to the fill adapter, during the transfer of product, especially at the end of the product transfer when the hose is lifted and drained of any remaining product, some twisting of the nozzle occurs. Such twisting of the hose can cause twisting of the fill adapter, loosening it from the riser line. To prevent such loosening of the fill adapter from the riser line, fill adapters are often equipped with set screws which lock them to the riser line. While such a practice prevents the fill adapter from loosening from the riser, it can cause twisting of the entire riser. This can sometimes cause the riser to loosen from the tank collar. The loosening of any of the fittings or connectors on the riser line is to be avoided as it can lead to product or vapor leakage, or product contamination. 
     At least one known swivel fitting has been developed for fill adapters to permit rotation of the nozzle with respect to the riser line without causing any loosening of either the connection between the fill adapter and riser line, or the riser line and underground storage tank. One such fitting is sold by OPW Fueling Components of Cincinnati, Ohio, and is illustrated in U.S. Pat. No. 5,664,951. 
     The &#39;951 patent discloses a two-piece swivel adapter which uses a flexible, electrically conductive rod to rotatably couple the two pieces of the adapter. However, the rotation achieved by this swivel adapter can be rough. Thus there exists a need for an improved swivel fitting which provides smooth and even rotation. 
     SUMMARY OF THE INVENTION 
     An improved swivel fitting is disclosed which permits a typical top seal delivery nozzle to freely and smoothly rotate with respect to the riser line associated with an underground product storage tank. This simplifies the transfer of product from the tanker truck to the product tank by permitting some twisting of the transfer hose. Such twisting is permitted without causing any loosening of the fittings associated with the riser line as can be experienced when rigid connections are used. 
     A rotatable swivel fitting is provided in combination with an inlet conduit for an underground liquid storage tank. The rotatable swivel fitting is connected on one end to the inlet conduit for the tank. The opposite end of the swivel fitting is connected to a supply hose for supplying liquid to the underground storage tank. The fitting includes an adapter sleeve that has an inlet, an outlet and a first internal flow passage extending therebetween. The outlet of the adapter sleeve is fixedly secured to the inlet conduit so as to bring the first internal flow passage in fluid communication with the inlet conduit. The fitting also has a swivel sleeve with an inlet and an outlet. The swivel sleeve has a second internal flow passage extending between its inlet and outlet. The second inlet is adapted to be in selective fluid communication with a hose for supplying liquid to the storage tank. The outlet of the swivel sleeve is rotatably interconnected to the inlet of adapter sleeve and the second internal flow passage is in fluid communication with the first internal flow passage. 
     The adapter sleeve has an external surface of revolution about a first axis with an external annular groove. A swivel sleeve is rotationally movable with respect to the adapter sleeve. The swivel sleeve has an internal surface of revolution about a second axis that is coincident with the first axis. The internal surface of revolution of the swivel sleeve has a diameter that is slightly greater than the diameter of the external surface of revolution of the adapter sleeve, with the external surface of the adapter sleeve being at least partially fitted within the internal surface of the swivel sleeve. The swivel sleeve has a internal annular groove that is in axial alignment with an external annular groove of the adapter sleeve, forming a channel. 
     A plurality of ball bearings are located within this channel, partially located in both the external and internal annular grooves of the respective sleeves. The bearings allow relative rotation between the adapter and swivel sleeves, while preventing axial motion between the two sleeves. The bearings provide a free, smooth rotation between the adapter and swivel sleeves. 
     Still other objects of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration, of one of the best modes contemplated for carrying out the invention. As will be realized, the invention is capable of other different obvious aspects all without departing from the invention. Accordingly, the drawings and description will be regarded as illustrative in nature and not as restrictive. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. Other features, aspects and advantages of the present invention will be fully understood when considered with respect to the following detailed description, appended claims, and accompanying drawings where: 
     FIG  1 . is a cross-sectional view of one embodiment of the present invention showing the interface between the swivel fitting and the inlet conduit; and 
     FIG. 2 is a partial sectional plan view of the fitting of FIG. 1, showing the channel containing the ball bearings. 
    
    
     Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings, wherein like numerals indicate the same elements throughout the views. 
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 partially shows a riser line  18 , which extends generally upward from the top of an underground tank (not shown). The riser line  18  extends upward through a spill container (not shown) where it is accessible for connection therewith. A drop tube  19 , partially obscured by the riser line  18  in FIG. 1 is concentrically disposed within the riser line  18 . While the riser line  18  extends only to the top of an underground tank, the drop tube  19 , disposed concentrically within the riser line, extends below the riser line  18  and into the tank, with the lower end of the drop tube  19  terminating near the bottom of the underground tank. 
     The swivel fitting  30  has two main components: the lower portion is the adapter sleeve  32 , and the upper portion is the swivel sleeve  34 . As illustrated, the upper external portion of the illustrated riser line  18  is threaded, and this external threaded portion of the riser line  18  receives the internally threaded adapter sleeve  30 . While the use of a threaded connection between the fitting and riser line is generally preferred, the fitting could be sealed to the riser line using a tapered pipe thread in combination with pipe dope or other conventional threaded pipe sealing material. Similarly, the adapter sleeve could be attached to the riser line by a flanged fitting or any number of other pipe connections as are well known in the art. If desired, the fitting could even be more permanently attached to the riser line such as by welding. 
     In many instances, the riser line  18  will be connected to the fitting  30  indirectly through riser line extensions or spill container components and the like, and not directly connected as shown in the specifically illustrated embodiment. Regardless as to whether the connection is direct or indirect, the fitting defines an internal flow passage that is in fluid communication with the storage tank inlet conduit, either directly with the drop tube as illustrated, or through intermediate components, to provide a liquid flow path for filling the underground tank. 
     As those skilled in the art will readily appreciate, the spill container provides a sealed enclosure for interconnecting between a supply hose (not shown) of a tanker truck and an inlet conduit to the underground tank. The spill container functions to contain any spills that occur during the process of filling the tank, and to protect the surrounding ground soil from contamination. The swivel fitting  30 , which is used to interface between the inlet conduit and the supply hose, is preferably located in the spill container. It also will be appreciated that the swivel fitting  30  normally has a cap (not shown in the drawings) that seals the inlet conduit when the inlet conduit is not in use. 
     In accordance with the principles of the invention, and as is apparent from FIG. 1, the swivel fitting  30  includes an adapter sleeve  32  and a swivel sleeve  34 , which components are relatively rotatable with respect to each other. The adapter sleeve  32  includes a lower portion  36  and an upper portion  38 . The lower portion  36  of the adapter sleeve  32  includes an internally threaded surface  40  that is adapted and sized to fit permit the adapter sleeve to be threaded to the exterior threaded surface of the riser line  18 . The upper portion  38  of the adapter sleeve is of slightly smaller diameter than the lower portion  36  and includes three annular grooves: an upper external annular groove  42  proximal to upper end of the upper portion  38  of the adapter sleeve  32 , a lower external annular groove  44  proximal to the lower end of the upper portion  38  of the adapter sleeve  32 , and a middle external annular groove  48  located intermediate the grooves  42  and  44 . O-rings  50  and  52  are disposed in the grooves  42  and  44  respectively to provide rotary seals between the adapter and swivel sleeves  32  and  34  respectively. The O-rings  50  and  52  form a seal between the outer wall of the adapter sleeve  32  to the inner wall of the swivel sleeve  34 . In the preferred embodiment, the O-rings are coated with TEFLON® to reduce friction. Such TEFLON®-coated O-rings are manufactured by M-Cor, Inc. of Wood Dale, Ill. and are sold under the name NCAP-O-SEAL™. 
     The lower portion  36  of the adapter sleeve  32  has a plurality of angularly spaced bosses  54  on its exterior diameter which are useful for threading the lower portion  36  onto the riser line  18 . A first gasket  56  is interposed between a horizonal seat  58  above the threaded surface  40  of the lower portion  36  of the adapter sleeve and the top side of a flange  59  of the drop tube  19  to provide a liquid seal between the adapter sleeve  32  and the drop tube  19 . A second gasket  61  is positioned along the lower side of the drop tube flange  59  and the riser line  18  to provide a vapor seal to prevent leakage of vapor rising in the concentric space between the drop tube  19  and the riser line  18 . The gaskets  56  and  61  are compressively engaged as the lower portion  36  of the fitting  30  is rotated onto the riser line  18 . The lower section  36  of the adapter sleeve  32  also includes two threaded apertures  62  (only one of which is shown in FIG. 1) through which set screws  64  are advanced to secure the lower section  36  relative to the riser line  18  once the lower section  36  is rotated to a tightened position. 
     The swivel sleeve  34  of the illustrated fitting  30  has three general sections: a lower section  66 , an intermediate section  68  and an upper section  70 . The lower section  66  of the swivel sleeve has an internal diameter that is slightly larger than the external diameter of the upper portion  38  of the adapter sleeve  32 . The lower section  66  of the swivel sleeve also has an axial dimension that generally corresponds to the axial dimension of the upper portion  38  of the adapter sleeve  32  so as to allow the upper portion  38  of the adapter sleeve  32  to be substantially fully disposed within the lower section  66 . The upper section  70  of the swivel sleeve  34  has an external diameter that is substantially equivalent to the external diameter of the lower section  66 . The intermediate section  68  has an external diameter that is reduced relative to both the lower and upper sections  66  and  70  respectively. The reduced diameter of the intermediate section  68  functions to provide a quick release fitting for a seal cap (not shown) or a top seal delivery nozzle (not shown) that are fitted over the top of the swivel sleeve  34 . Quick release fittings, such as a top seal delivery nozzle, are well known in the art for providing a convenient means of connecting a product delivery hose to a riser line during transfer of product from a tanker truck to the underground storage tank. Such fittings or fill adapters permit quick connection and disconnection of the nozzle of the delivery hose to the riser line, or quick connection and disconnection of a cap to the riser line. 
     The lower section  66  of the swivel sleeve  34  has an internal annular groove  72  that is positioned in axial correspondence to the external annular groove  48  of the adapter sleeve  32 . FIG. 2 illustrates how the internal annular groove  72  of the swivel sleeve  34  cooperates with the external annular groove  48  of the adapter sleeve  32  to form a channel  74  for receiving a plurality of ball bearings  75 . In the preferred embodiment, the ball bearings are packed in lubricating grease in the channel  74 . In other embodiments, other lubricating media may also be used, or the ball bearings may be used with no lubrication. In a preferred embodiment, the swivel sleeve  34  defines a bearing opening  76  for inserting the ball bearings  75  into the channel  74 . The bearing opening  76  is also used to insert any lubricating media, such as packing grease, into the bearing channel  74 . In the preferred embodiment, the bearing opening  76  extends tangentially from the horizontal circumference of the channel  74 . It will be appreciated that a variety of other configurations might also be used, such as an opening perpendicular to the horizontal circumference of the channel. 
     The ball bearings  75  are inserted into the channel  74  through the bearing opening  76  in the lower portion  66  of swivel sleeve  34 . In the preferred embodiment, the bearing opening  76  is threaded, and a set screw (not shown) is used to close the bearing opening  76  once the ball bearings are in the channel. In the preferred embodiment, an additional opening  78  in the lower portion  66  of swivel sleeve  34  is provided, proximate to the bearing opening  76  and along the horizontal circumferential plane of the channel  74 . This additional opening  78  is adapted to receive a tool for pushing the ball bearings  75  out of the channel  74  through the bearing opening  76 . In the preferred embodiment, the additional opening  78  has a diameter less than that of the ball bearings, so that the ball bearings may not exit the channel through the additional opening  78 . A wire, flexible rod or other tool is inserted into the additional opening  78  and used to push the ball bearings out through the bearing opening  76  such as may be required for routine maintenance of the fitting. In the horizontal circumferential plane of the channel  74 , the majority portion of the volume of the channel  74  between the bearing opening  76  and the additional opening  78  is adapted to receive bearings; the remaining minority portion of the volume of the channel between the bearing opening  76  and the additional opening  78  is blocked by a key  79  so that ball bearings may not enter into this portion of the channel  74 . It will be appreciated that the placement of the additional opening  78  along the external surface of the swivel sleeve  34 , and thus along the wall of the channel  74 , may be varied, and the additional opening  78  may be located on, above or below the horizontal centerline of the channel  74 . 
     In the preferred embodiment, the ball bearings  75  may be easily removed through the bearing opening  76 . A flexible tool or “snake” my be inserted into the additional opening  78  to force the ball bearings out of the channel  74  through the bearing opening  78 . In another embodiment, a secondary bearing opening is provided, and ball bearings may be inserted into or removed from the channel through either opening. In such an embodiment, the secondary bearing opening may be closed with a set screw, similar to the preferred closure of the opening  76 . It will be appreciated that the insertion and/or removal of ball bearings into the channel  74  may be accomplished in a variety of other manners, including openings perpendicular to the fitting  30 , multiples openings along the outer wall of the swivel sleeve  34 , or even a single opening in the outer wall of the swivel sleeve  34 . 
     The bearings allow the adapter sleeve  32  and swivel sleeve  34  to rotate relative to each other, while simultaneously restricting these components from relative axial movement. In a preferred embodiment of the present invention, both the adapter sleeve  32  and the swivel sleeve  34  are formed of a durable and electrically conductive material, most preferably bronze. Further, in accordance with the preferred embodiment of the invention, the bearings are also formed of an electrically conductive material, preferably stainless steel. Hence, the bearings provide an electrical path between the adapter sleeve  32  and swivel sleeve  34  so as to prevent static electricity buildup, eliminating the need for grounding plates. However, it will be appreciated that in other embodiments, the adapter sleeve, swivel sleeve, ball bearings, or any combination of the three may be formed from non-conductive materials. The primary requirement is that the material of construction allow free and smooth rotation between the adapter sleeve and the swivel sleeve. 
     In another embodiment of the preferred invention, relative axial motion between the adapter sleeve and the swivel sleeve is prevented by a secondary method, in addition to the ball bearings. Thus in the event of a failure of the bearings, or during replacement or repacking of the bearings, the cooperation relative axial motion between the adapter sleeve  32  and the swivel sleeve  34  is still limited, without the necessity of bearings. In the preferred embodiment, the lower section  66  of the swivel sleeve has a second internal annular groove  80 . This internal annular groove  80  is in axial alignment with a threaded aperture  82  in the upper portion of the adapter sleeve  32 . A set screw  84  extends through the aperture  82  and projects beyond the outside diameter of the adapter sleeve&#39;s upper portion  38 . The projecting structure formed by the set screw varies the diameter of the upper portion  38  and extends into the groove  80 . Preferably, the set screw  84  is not advanced so far into the groove  80  as to hinder relative rotation, and the surfaces of the groove  80  are spaced from the set screw, both radially and axially. The annular groove has upper and lower surfaces that are respectively spaced axially above and below the projecting structure. The annular groove also has an annular surface that is radially spaced from the projecting structure. The projecting surface extends into the annular groove so that the projecting structure and annular groove cooperate to prevent axial movement between the adapter sleeve and the swivel sleeve for a distance greater than the axial spacing between the projecting structure and the groove. As those skilled in the art will readily appreciate, such spacing allows the adapter sleeve  32  and the swivel sleeve  34  to rotate freely relative to each other. This arrangement also limits axial movement relative between the adapter sleeve and the swivel sleeve to the axial spacing between the set screw  82  and the groove  80  in the event the ball bearings  75  fail or are removed from the channel. It will be appreciated that in another embodiment of the present invention, the location of the projecting structure and the corresponding annular groove could be reversed, e.g., the projecting structure could be located on the inner surface of the swivel sleeve, and the annular groove could be located on the out surface of the adapter sleeve. 
     In the preferred embodiment, the projecting structure projects radially outwardly from the adapter sleeve and the diameter of the adapter sleeve at the location of the projecting structure is greater than the diameter of those portions of the adapter sleeve that are axially adjacent to the projecting structure. Again, it will be appreciated that in another embodiment, the projecting structure projects inwardly from the inner surface of the swivel sleeve, and that the diameter of the swivel sleeve at the location of the inwardly projecting structure is less than the diameter of those portions of the swivel sleeve that are axially adjacent to the projecting structure. 
     In a preferred embodiment of the present invention, the projecting structure is a set screw that is adjustably extendable from the adapter sleeve in a radially outward direction. 
     It will be appreciated that in another embodiment, where the annular groove is located on the outer surface of the adapter sleeve, the projecting structure is a set screw that is adjustably extendable from the swivel sleeve in a radially inward direction. 
     The swivel fitting of the present invention is preferably constructed of a durable metal or metal alloy as is well known in the art. In the preferred embodiment, the adapter sleeve and the swivel sleeve of the fitting are constructed of bronze. Bronze is preferred for its desirable electrical grounding properties. For durability, the ball bearings are preferably constructed of stainless steel. It will be appreciated that any number of other materials that provide the required durability or electrical conductivity might also be used. 
     The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described in order to best illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto. While the presently preferred embodiment of the invention has been disclosed, a number of variations would be apparent to one of ordinary skill in the art based on the above disclosure. Other changes in the form and detail of the preferred embodiment may similarly be made without departing from the spirit and scope of the invention which is intended to be defined by the following claims.