Patent Application
20090199927
The present invention relates generally to entry fittings, and more particularly, to tank entry fittings for use in fuel dispensing systems.
Fuel dispensing systems used at retail gas stations typically include an underground tank containing gasoline, diesel fuel or other liquid fuels, an above ground dispensing unit terminating in a nozzle adapted to supply the fuel to a motor vehicle, and a piping system interconnecting the underground tank and dispensing unit. The piping system includes a number of components that present potential leak sites in the piping system. While infrequent, to reduce the risks of fuel leaking into the environment, such components are typically located within a sump configured to contain the fuel therein in the event of a leak in the piping system. For example, the piping system may include a sump associated with the underground storage tank, referred to as the tank sump, and a sump associated with the dispensing unit, referred to as the dispenser sump. Typically, rigid, fluid-carrying conduit lines pass into and out of the sumps via openings or apertures in the wall of the sumps. The piping system further includes entry fittings at the location where the conduit lines pass through the wall of a sump so as to form a seal therebetween and prevent any fuel from leaking from the sump on the occasion of a leak in the piping system and collection of fuel within the sump.
A variety of entry fittings are known in the art that have been developed in response to the foregoing potential problem. While these entry fittings are generally successful for their intended purposes, manufacturers continually strive to improve such fittings to meet consumer needs as well as to satisfy various governmental regulations. By way of example, some entry fittings have a generally rigid construction so as to form a seal between the sump wall and the fluid conduit. Such rigid entry fittings, however, may not provide for relative movement between the sump and fluid conduit, which may occur due to frost heave and other environmental conditions, as is known in the art. The inability to accommodate relative movement between the sump and fluid conduit may hasten failure of the seal. Other entry fittings may have a resilient construction so as to accommodate relative movement between the sump and the fluid conduit. For example, such entry fittings are typically made of flexible materials (e.g., rubber-based materials, thermoplastics, etc.). Resilient entry fittings, however, are potentially more susceptible to ozone and fuel degradation. Additionally, such resilient entry fittings may not be conducive to bonding techniques used to form the seal between the entry fitting and the sump wall. Such bonding techniques have proven reliable and are considered desirable in the industry.
In addition to the above, many current entry fittings do not readily conform to non-planar surfaces. By way of example, some sump tanks may be generally cylindrical, thus having generally arcuate side walls through which the fluid conduit(s) extend. Because the side walls have some finite curvature, traditional entry fittings designed for generally planar walls may not sufficiently conform thereto to provide a fluid-tight seal. Various ad hoc approaches must then be used in an attempt to provide a reliable seal between the sump and entry fitting.
It is therefore desirable to provide an improved entry fitting for use in fuel dispensing systems that addresses these and other aspects of existing entry fitting designs.
To these ends, an embodiment of the invention contemplates a tank entry fitting for a fluid conduit line passing through an opening in a wall having a housing adapted to be inserted into the opening and including a first end portion, a second end portion, and a passageway extending therebetween for receiving the fluid conduit line therethrough. The housing further includes a rigid portion that defines a mating surface that forms a bonded joint with the wall, wherein the bonded joint forms a fluid tight seal between the housing and the wall. The entry fitting further includes a flexible coupling member having a first end portion coupled to the housing, a second end portion coupled to the fluid conduit line, and a passageway extending therebetween for receiving the fluid conduit line therethrough. The flexible coupling member forms a fluid tight seal between the housing and the fluid conduit line. Such an entry fitting provides a rigid portion which is conducive to bonding with the wall and a resilient portion that provides for relative movement between the conduit line and the wall.
In one embodiment, a flange projects outwardly from the housing and defines the mating surface for forming the bonded joint with the wall. In some applications, the wall may be non-planar. In such applications, at least a portion of the flange has a non-planar shape that corresponds to the shape of the wall. Such corresponding shapes facilitate bonding between the housing (e.g., flange) and the wall. The flange may be bonded to the wall on either side thereof (e.g., internal or external to a tank) and the flexible coupling member may be positioned on either side of the wall. In another embodiment, the housing includes a generally L-shaped flange projecting inwardly thereof so as to define a cavity for receiving an access or duct pipe therein.
An entry fitting that may be particularly conducive to double-walled tanks includes a first housing having a first end portion, a second end portion, and a passageway extending therebetween that receives the fluid conduit line therethrough, and a second housing including a first end portion, a second end portion, and a passageway extending therebetween that receives the fluid conduit line therethrough. The first end portion of the second housing is coupled to the second end portion of the second housing and at least one of the first or second housing includes a mating surface coupled to the wall so as to form a fluid tight seal therebetween. A first flexible fluid coupling member includes a first end portion coupled to one of the first or second housing, a second end portion coupled to the fluid conduit line, and a passageway extending therebetween that receives the fluid conduit line therethrough. The flexible coupling member forms a fluid tight seal between one of the first or second housing and the fluid conduit line.
In one embodiment, a flange projects outwardly from the first housing to define a mating surface for coupling to the wall. The mating surface may, for example, be bonded to the wall. A flange may also project outwardly from the second housing and also define a mating surface for coupling to the wall. Again, the mating surface may be bonded to the wall. At least one of these flanges may be non-planar in shape to correspond to a non-planar wall. In such an embodiment, the entry fitting may further include a second flexible coupling member including a first end portion coupled to one of the first or second housing, a second end portion coupled to the fluid conduit line, and a passageway extending therebetween that receives the fluid conduit line therethrough. In one embodiment, the first and second flexible coupling members are coupled to the same housing and are configured to define an interstitial space between the two flexible coupling members. Such an interstitial space may be achieved by including a stepped configuration in one of the housings, such as the second housing, for example, that defines a first bearing surface and a second bearing surface spaced therefrom. The first flexible coupling member may be coupled to the second housing at the first bearing surface and the second flexible coupling member may be coupled to the second housing at the second bearing surface. The second bearing surface may be spaced from the first bearing surface due to the stepped configuration of the second housing or by locating the second bearing surface on an outer flange of the second housing. One of the flexible coupling members may include an access port in fluid communication with the interstitial space for monitoring level changes, temperature, etc.
In one embodiment, a fuel dispensing system having a fluid conduit line includes a tank with at least one wall thereof defining an opening for receiving the fluid conduit line therethrough, and a tank entry fitting for forming a seal between the fluid conduit line and the tank. The tank entry fitting includes a housing inserted into the opening and having a first end portion, a second end portion, and a passageway extending therebetween for receiving the fluid conduit line therethrough. The housing further includes a rigid portion that defines a mating surface that forms a bonded joint with the wall, wherein the bonded joint forms a fluid tight seal between the housing and the wall. The entry fitting further includes a flexible coupling member having a first end portion coupled to the housing, a second end portion coupled to the conduit line, and a passageway extending therebetween for receiving the conduit line therethrough. The flexible coupling member forms a fluid tight seal between the housing and the fluid conduit line.
In another embodiment, a fluid dispensing system includes a tank having at least one wall thereof defining an opening for receiving the fluid conduit line therethrough, and a tank entry fitting for forming a seal between the fluid conduit line and the tank. The wall includes an inner shell, and outer shell, and an interstitial space therebetween. The entry fitting includes a housing inserted into the opening and having a mating surface for coupling to the wall adjacent the opening so as to form a fluid tight seal between the housing and the wall. The entry fitting further includes a pair of redundant flexible coupling members for forming a fluid tight seal between the housing and the fluid conduit line. The redundant coupling members may be configured to define an interstitial space therebetween which may be monitored for leaks.
These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings wherein:
The fuel dispensing system 10 further includes a number of concealment tanks or enclosures, such as sump tanks, for example, for containing fuel on the occasion that a leak forms in the fuel dispensing line. Such concealment tanks are adapted to prevent or reduce the likelihood that any fuel will leak to the surrounding environment in the event of a leak in the fuel dispensing line. As illustrated in
As shown in
The housing 52 may be formed from a suitable, relatively rigid material. For example, the housing 52 may be formed from plastic, fiberglass, sheet molding compound (SMC), thermosets, thermoplastics, metal, etc. In one embodiment, the housing 52, including the flange 60, may be integrally formed from a moldable polymeric material such that the housing has a unitary structure. The invention, however, is not so limited as the flange 60 may be coupled with the housing 52 as a separate component or element through various processes including welding, adhesives, and other suitable processes. Moreover, the housing 52 may be sized and shaped so as to fit snugly within the opening 42 in side wall 44 when mounted thereto. For example, the housing 52 may be generally circular in cross-sectional shape so as to fit within a generally circular opening in a tight manner. The housing 52 and opening 42 may, however, have other corresponding cross-sectional shapes including rectangular, triangular, oval, etc.
In one embodiment, when the housing 52 is mounted to sump 34, the flange 60 may be located exterior to the sump 34 such that an inner surface 64 of the flange 60 abuts the outer surface 66 of the sump 34 and operates as a mating surface. To effectuate a seal between the housing 52 of the entry fitting 50 and the sump 34, a bonded joint 68 is formed along at least a portion of the interface between the inner surface 64 of the flange 60 and the outer surface 66 of the sump 34. The bonded joint 68 forms a fluid tight seal between the housing 52 and the sump 34 so that no fuel may escape from the sump 34 through the interface therebetween on the occasion of a leak and collection of fuel within the sump 34. Various adhesives may be used to form the bonded joint 68 including two-part (meth)acrylate compositions (e.g., Plexus®), or other suitable adhesives sufficient to provide a fluid tight seal between the housing 52 and the sump 34. In addition to the above, a bonded joint 70 may also be formed at the interface between the wall portion that defines opening 42 and the outer surface 62 of the housing 52 adjacent the flange 60.
In one aspect of the invention, at least a portion of the flange 60 may be profiled or contoured so as to substantially correspond to the shape of the side wall 44 adjacent opening 42. By way of example, sump tanks are commercially available that have either a rectangular configuration with generally planar surfaces, or a cylindrical configuration with generally arcuate surfaces (e.g., surfaces with a finite and constant radius of curvature). Thus, in one embodiment, the flange 60 has a generally planar configuration such that the inner surface 64 of the flange 60 mates with a generally planar side wall of the sump (not shown). In an alternative embodiment, however, and as illustrated in
The contouring of at least a portion of the flange 62 may be achieved in several ways. For example, the entire flange 60 may be contoured so as to substantially correspond to the shape of the sump side wall 44 adjacent the opening 42, as shown in
In one embodiment, a plethora of housings 52 may be provided having flanges 60 with inner surfaces 64 with different radii of curvature to correspond to different sized sumps 34. Once the size of the sump is determined, the appropriately sized housing may then be selected. In another embodiment, however, a housing 52 having a flange 60 with an inner surface 64 with a specific radius of curvature may be used on sumps having a size approximate to, but not necessarily equal to, that of the inner surface 64. By way of example, a housing 52 having a flange 60 shaped so as to have a radius of curvature of approximately 22.5 inches may be used on sumps having inner diameters of between approximately 42 inches and approximately 48 inches. Thus, while the shape of the inner surface 64 of the flange 60 and the side wall 44 of the sump 34 do not have to precisely match, the inner surface 64 and side wall 44 must sufficiently correspond in shape such that a suitable bonded joint 68 may be formed.
The fluid tight seal between the housing 52 and the sump 34 forms but one part of the total sealing function of the tank entry fitting 50. Additionally, a seal must also be formed between the housing 52 and the fluid conduit line 18. In this regard, the tank entry fitting 50 further includes a generally flexible coupling member, such as flexible boot 76. Flexible boot 76 includes a first end portion 78 adapted to be coupled to the second end portion 56 of the housing 52 in the interior of sump 34, a second end portion 80 adapted to be coupled to the fluid conduit line 18, and a passageway 82 extending between the first and second end portions 78, 80 and adapted to receive the fluid conduit line 18 therethrough. The first end portion 78 of boot 76 may be sized to approximately correspond to the size of the second end portion 56 of the housing 52 so as to be received thereon in a slight friction fit. Additionally, the second end portion 80 of boot 76 may be sized to approximately correspond to the size of the fluid conduit line 18. For example, the size of the second end portion 80 may be slightly smaller than fluid conduit line 18 such that the fluid conduit line 18 is tightly received therein. The first and second end portions 78, 80 of the boot 76 may be secured to the second end portion 56 of the housing 52 and fluid conduit line 18, respectively, using clamping members, such as band clamps 84.
The boot 76 may be formed from a suitable, relatively resilient material. For example, the boot 76 may be formed from elastomers, including thermoplastic polyurethane elastomers (e.g., Pellethane®), suitable natural or synthetic rubbers (e.g., nitrile rubber or Buna-N), or other suitable materials.
The tank entry fitting 50 shown and described above has several advantages over existing entry fittings. In particular, in one aspect, the tank entry fitting 50 includes a first relatively rigid portion (e.g., housing 52) that forms a first seal with the sump 34, and a second relatively flexible portion (e.g., boot 76) that forms a second seal with the fluid conduit line 18. The rigid construction of the first portion may provide advantages regarding the bonded joint 68. In this regard, the use of bonding techniques has gained significant commercial acceptance in the industry due to its perceived reliability in the field. However, the use of bonding techniques is generally limited to the coupling of relatively rigid materials, as its use with relatively flexible materials may be problematic. Thus, entry fittings primarily made of resilient materials may not make use of bonding to effectuate a seal with either the sump or the fluid conduit line. Accordingly, such resilient entry fittings may be considered unreliable in the field. As noted above, because the housing 52 is formed from a relatively rigid material, a bonding technique may be used to effectuate a seal between the housing 52 and the sump 34. In addition, some commercially available sumps are formed from fiberglass, which is highly conducive to bonding techniques. Therefore, forming the first portion of the tank entry fitting 50 from a relatively rigid material provides for the use of bonding techniques, which is not only considered desirable by the industry, but also results in a strong, reliable seal formed between the housing 52 and the sump 34.
Notwithstanding that above, the flexible construction of the second portion may also provide certain advantages. In particular, the ability of the second portion to flex enhances the coupling between the entry fitting 50 and the fluid conduit line 18. In this regard, a rigid connection between the entry fitting and the fluid conduit line 18 requires relatively precise alignment of the conduit line relative to the entry fitting. Achieving such precise alignment, however, may entail a trial-and-error approach that is time consuming and costly. Moreover, the fuel dispensing system is typically a dynamic system, not a static system. For example, for those systems that have at least a portion thereof underground (
Another advantage provided by the tank entry fitting 50 described above is that the contouring of the entry fitting 50 at least along those portions that mate with sump 34 (e.g., inner surface 64 of flange 60 or flange 60 as a whole) so as to more closely match that contour of the sump 34 provides for an improved connection therebetween. For example, using a generally planar portion on an entry fitting to mate with a cylindrical wall of a sump may result in a connection that cannot be bonded, a connection that requires an excessive amount of adhesive, and/or a connection that is unreliable in the field. As noted above, by contouring at least a portion of the flange 60 (e.g., the mating portion) to match the contour of the sump 34, a more reliable joint, such as bonded joint 68, may be formed therebetween.
Alternative embodiments to that shown in
In another embodiment, as shown in
The embodiment shown in
As shown in
The access pipe 90 may be coupled to the housing 52 via clamp 104. Clamp 104 has a multi-piece construction with, for example, an upper clamping portion 104a and a bottom clamping portion 104b (relative to the orientation shown in
The entry fitting 88 may further include a sealing member 118 that forms a fluid tight seal between the access or duct pipe 90 and the housing 52 when the access or duct pipe 90 is mounted thereto. For example, as shown in
In recent years, more comprehensive federal, state and local regulations regarding the release of fuels and other hazardous materials to the environment have been imposed on the industry in an attempt to limit their impact on the surrounding environment. Some states, such as California for example, have imposed regulations that require redundancy in systems that handle hazardous materials, including fuels. The redundancy may include, for example, providing double-walled containment structures. Where such regulations exist, and as illustrated in
As the entry fittings into the sumps represent potential leak sites, the regulations that require a double-walled sump may also require a tank entry fitting that provides the necessary redundancy and possibly even leak monitoring capabilities. An exemplary entry fitting in accordance with one embodiment of the invention directed to meeting or exceeding regulations in such jurisdictions is shown in
As shown in
The second housing portion 132 includes a flange 140 projecting outwardly from a terminating end of the first end portion 134 for mating the second housing portion 132 to the inner shell 122 of the sump 120. As noted above, in one embodiment, the second housing portion 132, including flange 140, may be integrally formed from a moldable polymeric material such that the housing portion 132 has a unitary structure. The invention, however, is not so limited as the flange 140 may be coupled to second housing portion 132 as a separate component or element. Moreover, the first end portion 134 of housing 132 is sized and shaped to correspond to the size and shape of the second end portion 56 of first housing portion 130 such that they mate in a relatively tight frictional fit. When the second housing portion 132 is mounted to the first housing portion 130, an outer surface 142 of the flange 140 abuts an inner surface 144 of the inner shell 122 of the sump 120 and operates as a mating surface. To effectuate a seal between the second housing portion 132 and the sump 120, a bonded joint 146 may be formed along at least a portion of the interface between the outer surface 142 of the flange 140 and the inner surface 144 of the inner shell 122 of the sump 120. The bonded joint 146 forms a fluid tight seal between the second housing portion 132 and the inner shell 122 so that no fluid (e.g., fuel, water) may escape from the sump 120 through the interface therebetween on the occasion of a leak and collection of fluid within the sump 120. The adhesives identified above in regard to entry fitting 50 may also be used for bonding the second housing portion 132 to the inner shell 122.
In addition to the above, a bonded joint 148 may also be formed at the interface between the wall portion that defines opening 42 through the inner shell 122 and the outer surface 62 of the first housing portion 130. A bonded joint 152 may further be formed at the interface where the first end portion 134 of the second housing portion 132 engages the second end portion 56 of the first housing portion 130.
Similar to flange 60 described above in regard to tank entry fitting 50, the flange 140 may be profiled or contoured so as to substantially correspond to the shape of the inner surface 144 of the inner shell 122 adjacent opening 42. Thus, in one embodiment, the flange 140 has a generally planar configuration that mates with a generally planar side wall of the sump 120. In an alternative embodiment, however, and as illustrated in
The second housing portion 132, or at least an outer surface 154 thereof, has a stepped configuration defining a first bearing surface 156, a second bearing surface 158, and an outwardly directed shoulder 160 therebetween such that the second bearing surface 158 is spaced outwardly relative to the first bearing surface 156, as illustrated in
The first boot 162 includes a first end portion 166 adapted to be coupled to the first bearing surface 156 of the second housing portion 132, a second end portion 168 adapted to be coupled to the fluid conduit line 18, and a passageway 170 extending between the first and second end portions 166, 168 and adapted to receive the fluid conduit line 18 therethrough. The first end portion 166 of boot 162 may be sized to approximately correspond to the size of the first bearing surface 156 so as to be received thereon in a slight friction fit. Additionally, the second end portion 168 of boot 162 may be sized to approximately correspond to the size of the fluid conduit line 18. For example, the size of the second end portion 168 may be slightly smaller than fluid conduit line 18 such that the fluid conduit line 18 is tightly received therein. The first and second end portions 166, 168 of the boot 162 may be secured to the first bearing surface 156 of the second housing portion 132 and fluid conduit line 18, respectively, using clamping members, such as band clamps 84.
In a similar manner, the second boot 164 includes a first end portion 172 adapted to be coupled to the second bearing surface 158 of the second housing portion 132, a second end portion 174 adapted to be coupled to the fluid conduit line 18, and a passageway 176 extending between the first and second end portions 172, 174 and adapted to receive the fluid conduit line 18 therethrough. The first end portion 172 of boot 164 may be sized to approximately correspond to the size of the second bearing surface 158 so as to be received thereon in a slight friction fit. Additionally, the second end portion 174 of boot 164 may be sized to approximately correspond to the size of the fluid conduit line 18. For example, the size of the second end portion 174 may be slightly smaller than fluid conduit line 18 such that the fluid conduit line 18 is tightly received therein. The first and second end portions 172, 174 of the boot 164 may be secured to the second bearing surface 156 of the second housing portion 132 and fluid conduit line 18, respectively, using clamping members, such as band clamps 84.
As illustrated in
Furthermore, as shown in phantom in
While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the inventor to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The various features of the invention may be used alone or in numerous combinations depending on the needs and preferences of the user.
