FLOW- HROUGH, IN-LINE FILTER APPARATUS AND IMPROVED COUPLING DEVICE

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to in-line filter apparatus and associated union apparatus for joining fluid-handling lines and filters to fluid handling lines, and more particularly to an improved filter and associated fluid flow-line coupling device having double sealing and leak trace capability.

Brief Description of the Prior Art In-line filters have long been used in water lines, fuel lines, chemical supply lines, etc. Such filter elements have typically involved a canister-type design with a removable top or bottom, allowing replacement of a filter element, or in the alternative, have utilized a sealed filter container of the throw-away type with couplings at either end. Pipeline union couplers and other couplers associated with filters, pumps, valves, etc., have also long been used in water lines, fuel lines, chemical supply lines, etc., and have typically depended upon the clamping together of either two planar or frusto-conically configured annular surfaces with or without O-rings. Such unions, however, are subject to leakage if not tightly clamped together or if the O- rings either have failed or lost their resiliency. Moreover, resilient O-rings can leach out in certain chemicals. For applications in which leak detection is required, a dual O-ring configuration having an intermediate groove and leak trace has been used. One such embodiment is disclosed in U.S. Patent No. 5,090,871 entitled "Junction Assembly With Leak Detection Means" issued to Carl E. Story and Kenneth M. O'Connor. While such dual O-ring structure was suitable for many applications, the dependency upon O-ring

integrity and clamping force uniformity left room for improvement .

SUMMARY OF THE INVENTION It is therefore a principal objective of the present invention to provide an improved in-line filter device suiting the above needs. Another objective of the present invention to provide an improved union assembly and coupling device having substantially universal application. Yet another object of the present invention is to provide an improved union or coupling device which can be molded from suitable plastics or metallic materials and used to join flow-lines together without the need for torque-applying wrenches. Still another object of the present invention is to provide a novel dual-sealed coupling device having leak trace capability. A further objective of the present invention is to provide a moldable union device in which a minimum of clamping force is required to achieve a leakless seal. Briefly, the present invention relates to the use of a novel sealing structure in coupling structures of the type used in in-line filter devices, fluid conduit union devices, etc. A filter incorporating the present invention might include a cylindrical barrel for receiving a removable filter element, a filter element adaptor and end cap assembly for connecting a flow line to one end of the barrel, and an input flow diffuser and end cap assembly for connecting the opposite end of the barrel to the flow line. A single union apparatus would include a pair of junction elements for attachment to the ends of flow lines to be connected and a coupling nut. In either case, a first element is provided with a coupling face having at least one annular groove and preferably a plurality of annular grooves formed therein circumscribing a fluid passageway. The sidewalls of the groove or grooves are angularly inclined relative to each other so that the transverse width of the groove

decreases with depth. The opposing face of the second junction element is provided with a mating annular rib or ribs, the transverse dimensions of which are selected such that each rib mates with an opposing groove of the first element whereby when the nut is turned to draw the two junction elements together, the sidewalls of each rib mate with the sidewalls of a corresponding groove and form seals therebetween. Preferably, the transverse dimension of the distal extremity of each rib is narrower than the proximal extremity and is such that the walls of each rib mate with the walls of a corresponding groove and the coupling pressure wedges them together forming pressure seals at the engaging sidewalls. In a dual sealing configuration, either or both of the junction elements may include an annular channel formed between the inner and outer annular sealing ribs/grooves, so as to retain and distribute any fluid leaking through the inner sealing junction. In a leak trace embodiment, a suitable leak sensor may be extended into sensing communication with the channel. An important advantage of the present invention is that it provides a simple single or multiple union type of coupling device having universal application. Another advantage of the present invention is that it provides a coupling device of the type described which can be sealingly engaged without the use of tools. Still another advantage is that, by adding additional rib/groove pairs, higher degrees of sealing can be achieved. These and other advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following detailed description of the preferred embodiment which is illustrated in the several figures of the drawing.

IN THE DRAWING Fig. 1 is a perspective view illustrating a filter assembly utilizing a junction structure in accordance with the present invention;

Fig. 2 is an exploded longitudinal, cross-sectional view illustrating the several components of the filter assembly illustrated in Fig. 1; Figs. 3a and 3b are partial cross-sectional views illustrating alternative types of sealing configuration using sealing rings of rectangular and diamond-shaped cross-section with tapered grooves; Figs. 4a and 4b are a partial cross-sectional views illustrating alternative forms of rib-and-groove 0- ringless seals in accordance with the present invention; Fig. 5 is a partially cut-away illustration of a coupling union in accordance with the present invention; and Fig. 6 is an exploded detail illustrating engagement of the rib-and-groove sealing mechanisms depicted in Fig. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to Fig. 1 of the drawing, a flow- through in-line filter assembly is illustrated including a filter housing barrel 10, a pair of end caps 12, and a pair of coupling nuts 14. Extending into apertures formed in each end cap 12 (only one of which is shown) is a leak trace detector 16 which will be described below. As will also be further described below, the cylindrical nipples 18, formed integral with each end cap 12, may be either removably or fixably attached, as by gluing, welding, fusing or the like, to an inlet conduit 20 and an outlet conduit 22, as indicated at 23 and 24, respectively. In Fig. 2 of the drawing, which is an exploded longitudinal cross-section of the embodiment depicted in Fig. 1, it will be noted that the barrel 10 is formed of an elongated cylindrical body having a first cylindrical bore 30 forming a chamber for receiving a filter element 32. At each end of the barrel 10 is a counter-bore 34 of a larger diameter than the bore 30, such bores being respectively adapted to receive an input flow diffuser 36 at one end and a filter element adaptor 38 at the

other end. In accordance with one embodiment, each end of barrel 1. is externally threaded, as indicated at 40, and includes an annular seal-receiving or seal-forming groove 42 formed in its end face. Alternatively, and as will be described below, the groove 42 could be an annular rib adapted to mate with a corresponding groove in end cap 12 so as to form an O-ringless seal. The flow diffuser 36 is a circular body having a central aperture 44 for receiving an input flow of liquid or gas, and has an outer diameter suitable for mating with the bore 34 of barrel 10. The outer surface 46 of one side is smooth with the exception of at least one annular seal-receiving or seal-forming groove 48. The opposite side 50 is variously configured to form flow paths serving to diffuse the input flow of gas or liquid so that it is more or less evenly distributed over the input end surface 31 of filter element 32. The adaptor 38 is of similar size and configuration to that of diffuser 36 in that its outer diameter is adapted to mate with the bore 34 at the other end of barrel 10, and its outer surface 52 is smooth, with the exception of a central aperture 54 and at least one annular seal-receiving groove 56. The opposite side 58 of adaptor 38 is configured to suitably engage the downstream end of the filter element 32 and direct the filtered flow of gas or liquid through the opening 54. Annular inner and outer seals 60 and 62 are in this embodiment respectively adapted to engage and seat within the inner annular grooves 48, 56 and the larger annular grooves 42. The end caps 12 are identical to each other and have an outer diameter of approximately that of barrel 10, and a smooth face 64 on one side for mating with the faces 46, 52 of the diffuser 36 and adaptor 38, respectively. The faces 64 have an inner aperture 66 for receiving filtered fluid or gas, an inner groove 68 for mating with the inner sealing ring 60, and an outer annular groove 70 for mating with the outer sealing ring 62 or rib as suggested above, and a counter-bored

- 6 - opening 72 for receiving the leak trace sensor 16. In addition, an annular groove 74 is also provided between the inner and outer grooves and in alignment and communication with the bore 72. The outer perimeter of the end caps 12 is also provided with a shoulder 76 for receiving a corresponding capture flange 78 of the end nuts 14. End caps 12 also include suitable stiffening webs 80.

The nuts 14 have a threaded inner bore 80 for mating with the threads 40 of barrel 10, and an end wall with an inner bore 82 forming the capture flange 78 for engaging the shoulder 76 of the end caps 12. The outer annular surface 84 of the nuts 14 may be multi-faceted, gnurled, or of any other suitable configuration for aiding in the manual rotation of the nut as it is threaded onto barrel 10.

This embodiment can be implemented using any imaterial suitable to the application. In one embodiment, the barrel 10, diffuser 36, adaptor 38, and end caps 12 are made of a PFA plastic. End nuts 14 are made of a PVDF plastic which is somewhat harder than the PFA. The inner and outer sealing rings 60 and 62 are made of a somewhat softer Teflon or PTFE plastic. The sealing rings 60 and 62 are of a rectangular cross- section, as indicated at 90 in Fig. 3a, or may be tapered or diamond-shaped in cross-section as depicted in Fig. 3b, and the annular grooves 42 and 48, 68 and 70 are inwardly tapered, as indicated in Figs. 3a and 3b, so as to form compression seals with the rings 90 and 90' .

In an alternative embodiment, the annular seal may be dispensed with in favor of an integrally formed or bonded sealing ring 92 or rib 92 ' , as depicted in Figs. 4a and 4b. If not formed integral with the end cap 12, it may be bonded directly to the face of one of the members and adapted to mate with a facing groove of the opposite member.

In operation, with the end caps 12 mounted to opposing ends of an external conduit and spaced apart a

distance slightly larger than the length of the barrel 10, it will be appreciated that the barrel containing a filter element 32, with diffuser 36 in place at one end and adaptor element 38 in place at the other end, and sealing rings 60 and 62 installed in their corresponding grooves 56 and 42, can be slipped into place between the faces 64 of the end caps 12, and the end caps can be drawn into sealing engagement with the ends of the barrel, and the diffuser and adaptor, by threading a pair of end nuts 14 onto the threads 40 of barrel 10. Similarly, when a filter needs changing, all one need do is back off the nuts 14, releasing the tension on the end caps, freeing the barrel and allowing its removal. The apparatus may be used either with or without the leak trace sensor 16. If used without the sensor 16, a plug would be provided in bore 72 to prevent leakage in the event of inner seal failure. If the sensors 16 are included, it will be appreciated that any failure of the inner seal 60 at either end will permit leakage into the annular channel 74 and immediately be communicated to the leak trace sense - 16 to be reported by a suitable monitoring apparatus :>t shown) . In the illustrated embodiment, an optical sensor such as that disclosed in U.S. Patent Application Serial No. 899,663 entitled "Optical Leak Detector and Position Sensor", may be used. Referring now to Fig. 5 of the drawing, application of the sealing principles of the present invention is shown applied to a union-type coupling device including a pair of junction elements 100 and 102, which are of similar configuration to the end caps 12 and diffuser 36/adaptor 38 of the previously described embodiment. Also included is a coupling nut 104 used to draw the junction elements 100 and 102 together in sealing engagement . Junction element 100 is preferably a molded plastic component having a generally cylindrical central portion 106 widened at 108 to form a mating end flange 110. The external annulus of flange 110 is threaded, as indicated

at 112, over at least a portion of its axial length. The end face 114 has at least one annular groove 116 formed therein and preferably both an outer groove 116 and an inner groove 118. End face 114 may also include an annular channel 120. In the preferred embodiment, a pair of laterally extending projections 122 and 124 are provided to form gripping surfaces for holding the junction element. A longitudinally extending bore 126 is provided in element 124 and is tapered at its internal extremity for receiving an optical light trace iof the type previously described. Note that the distal extremity 128 of bore 126 is tapered and extends into channel 120 by deforming the plastic material at 130. The deformation 130 allows the tip of an optical sensor inserted into bore 126 to experience a larger detection area of groove 120 and thus increase its sensitivity.

The mating element 102 is preferably likewise a lmolded plastic component having a generally cylindrical ιcentral portion 132 radially widened at 134 to form a lmating end flange 136. The external annulus of flange 136 is smooth so as not to interfere with nut 104. The <end face 138 is provided with at least one annular rib 140 and preferably a second annular rib 142 aligned with iand adapted to mate with the grooves 116 and 118, respectively, of element 100. Note that the ribs 140 iand 142 are tapered in the longitudinal direction of .element 102 such that the proximal portion of each rib is wider than the distal portion thereof. Moreover, the taper angle of each rib is preferably identical to that (of each groove. Ideally, the transverse width of the <distal extremity of each rib is slightly larger than the 1transverse width of the deepest part of each groove so ias to ensure ribbed groove interference before bottoming iout during the mating closure. Longitudinally extending <external ribs 144 are provided on cylindrical segment 132 to provide a means for facilitating rotation of element 102 relative to element 100.

Coupling nut 104 is generally cap-shaped with a <central bore 146 for receiving element 102, an interior

cavity 148 for receiving the flange portion 136 of element 102, internal threads 150 for mating with the external threads 112 of element 100, and flats or longitudinally extending ribs or gnurling 152 for facilitating rotation of the nut relative to element 100 so as to cause element 102 to clampingly engage element 100. It will of course be appreciated that the mating rib and groove detail of elements 100 and 102 could be reversed. Moreover, the diameter of bore 146 of cap 104 could be increased so as to provide clearance for allowing a sensor bore to extend into the flange 136 of element 102 for leak detection purposes. In Fig. 6, details of the rib-and-groove construction are enlarged to clearly illustrate the tapered nature of the ribs and grooves. It will of course be appreciated that more than two rib-and-groove combinations can be utilized, and the polarity of one or more of the rib-and-groove mechanisms could be reversed. Although the present invention has been described above in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. For example, one might use clamping rings or other mechanisms in place of the threaded nuts 14 and 104. Moreover, the annular grooves 74 might be formed in the faces 46, 52 of the diffuser 36 and adaptor 38, respectively. It is therefore intended that the following claims be interpreted as covering all such alterations and modifications as fall within the true spirit and scope of the invention.