Abstract:
Devices for cleaning vessels, especially swimming pools, are discussed. The devices may include a non-linear flow path in a gap surrounding an in-line valve. This non-linearity permits lengths of concentric pipes forming the gap to be decreased without sacrificing operational performance of the devices. Valves forming parts of the cleaning devices may be diaphragms but shaped, sized, reinforced, or configured differently than existing valves and may have collapsible segments whose interior shape resembles an ellipse in transverse cross-section. Co-molding of diaphragms and pipes may occur, and inner and outer cups may be used to fix relative positions of various components of the devices.

Description:
FIELD OF THE INVENTION 
   This invention relates to devices for cleaning fluid-containing vessels and more particularly, but not exclusively, to automatic cleaners for swimming pools and components of such cleaners. 
   BACKGROUND OF THE INVENTION 
   Commonly-owned U.S. Pat. No. 4,642,833 to Stoltz, et al. (the “Stoltz Patent”) discloses various valve assemblies useful for automatic swimming pool cleaners. These assemblies typically include flexible diaphragms surrounded by chambers, with the diaphragms interposed in the fluid-flow paths (i.e. “in-line”) through the cleaners. In response to variation in pressure internally and externally, the diaphragms contract and expand transversely along at least part of their lengths, thereby controlling fluid flow therethrough. 
   Typical diaphragms of the Stoltz Patent are tubular and made of an elastic material. As noted in the Stoltz Patent: 
   Where the tubular member is made from elastic material it may be made to have a downstream portion less elastic than the remainder and the length of the less elastic part of the tubular member may vary circumferentially adjacent the more elastic portion and the tubular member may be reinforced with fabric or other stranded material. 
   See Stoltz Patent, col. 1, 11. 62-68. Also described in the Stoltz Patent are inner circumferential ribs “extending along substantially 180° of the surface of the diaphragm and on opposite sides thereof.” Id., col. 2,11. 38-40 (numeral omitted). These circumferential ribs facilitate closing the diaphragms so as to prevent fluid from flowing therethrough. See id., col. 3, 11. 20-22. 
   Commonly-owned U.S. Pat. No. 4,742,593 to Kallenbach (the “Kallenbach Patent”) discloses additional valve assemblies for use with automatic swimming pool cleaners. These assemblies, also typically tubular and of flexible material, too may be interposed in-line, within the fluid-flow paths of such cleaners. According to the Kallenbach Patent: 
   The body [of the tubular valve] has an intermediate section between the ends that assumes a substantially collapsed condition over a segment thereof in absence of a pressure differential between the interior and exterior. The section preferably is collapsed transversely over a segment. 
   Along the collapsed segment, the body has diverging interior walls in the direction of water flow therethrough. The walls diverge from a substantially constant diameter that extends for a portion of the section adjacent the first end to a substantially constant, but larger, diameter that extends for a portion of the section adjacent the second end. Further, the divergence is a substantially linear function of the distance along the segment. 
   See Kallenbach Patent, col. 1, 11. 28-42. Also noted in the Kallenbach Patent is that 
   The section may be provided with longitudinal reinforcing ribs on each side extending from near the second end to the collapsed segment. 
   Further, vertical ribbing may be provided on the interior of the section on opposing surfaces proximate the collapsed segment. 
   Id. at 11. 43-47. At least some of the longitudinal ribs are designed to “serve as a means for stiffening the valve member in the axial or longitudinal direction.” Id., col. 3, 11. 53-55. 
   International Publication No. WO 02/01022 of Kallenbach, et al. (the “Kallenbach Publication”), entitled “Swimming Pool Cleaner,” details another cleaner in which a valve periodically interrupts a flow of water through the body of the cleaner. Included in the cleaner are a main flow path and a by-pass passage built into the body. See Kallenbach Publication, p. 5, 11. 8-11. Also included in one version is an “annular resilient rolling diaphragm” with an edge “located in sealing engagement with the inner wall of the body.” Id., p. 6, 11. 24-26. However, a dome-shaped valve closure member, rather than the rolling diaphragm, operates to interrupt fluid flow through the main path. Additionally, neither the rolling diaphragm nor the dome-shaped member is interposed in-line in the main water path from the inlet passage of the cleaner to the outlet of the body. 
   Each of the Stoltz and Kallenbach Patents and the Kallenbach Publication discusses “suction-side” cleaners in which a pair of concentric pipes exist, the outer of the pipes being adapted for connection to a flexible hose leading (directly or indirectly) to the inlet, or “suction side,” of a pump. An annular gap between the pipes permits water to flow through the by-pass passage of the cleaner of the Kallenbach Publication toward the flexible hose. A similar gap in versions of cleaners discussed in the Stoltz and Kallenbach Patents offers “suction communication . . . through slots to chamber” defined at least in part by the tubular members of these patents. The contents of the Kallenbach Publication, together with those of the Stoltz and Kallenbach Patents, are incorporated herein in their entireties by this reference. 
   SUMMARY OF THE INVENTION 
   The present invention provides alternatives to the devices addressed in these earlier efforts. Among features of the present invention are provision of a non-linear fluid flow path in an annular gap of a cleaner having an in-line valve. Hence, although the main flow path through a diaphragm-type valve may continue to be linear, the flow path associated with the annular gap need not be. Introducing non-linearity into this path permits the lengths of the concentric pipes, or conduits, to be decreased without sacrificing operational performance of the associated cleaners. The decreased lengths indeed often improve operational performance of the cleaners, as shorter pipes are less likely to be guided, or led, by the flexible hoses to which they are attached. Better power to weight ratios also exist for the cleaners because of the diminished material needed for the pipes. 
   Beneficially (but not necessarily), any such non-linearities will occur adjacent the valve. Preferably, moreover, the principal non-linearity will constitute a direction reversal in the form of a turn of approximately one hundred eighty degrees. Non-linearities of this sort are not the sole ones contemplated by the present invention, however; instead, helical or spiral paths, turns of other magnitude, etc., may be employed as appropriate or desired. 
   Flexible valve assemblies of the present invention additionally may differ from those of the Stoltz and Kallenbach Patents and the Kallenbach Publication. Unlike the diaphragms and closure members of the Kallenbach Publication, for example, valves of the invention may be positioned in-line in the main fluid flow path through the cleaners. Further, these valves may (but need not) be tubular, like many of the diaphragms detailed in the Stoltz and Kallenbach Patents. However, valves of the present invention may be shaped and sized differently than the diaphragms illustrated in the Stoltz and Kallenbach patents and may be of greater rigidity in their upper (downstream) sections. In some embodiments, longitudinally-oriented pins may be inserted into the valves for rigidity, while in other embodiments plastic material of low modulus of flexibility (substantially rigid thermoplastics, for example) may be used for this purpose. Respecting these latter embodiments, the plastic material may be the same as that used for the inner pipe, which is commonly considered to be rigid. 
   The innovative valves additionally assume a substantially elliptical internal transverse cross-section in the collapsible segments when such segments are collapsed, unlike the complex but substantially rectangularly cross-sectioned collapsed shapes of prior tubular diaphragms. This change permits greater fluid flow through collapsed segments of the valves without diminishing the power provided for cleaner movement by the repeated collapses. Combined with the greater rigidity described in the preceding paragraph, the change also results in less energy being required to expand the collapsed segments and the segments opening to greater extent before returning to collapsed positions. 
   Valves of the present invention may be co-molded with the inner pipes to which they normally attach. So doing may avoid the need for an attachment joint between these components of an automatic swimming pool cleaner. Avoiding an attachment joint in turn may avoid component portions at such joint from wearing frictionally because of contact of the differing materials. 
   Finally, novel mechanisms may be employed to maintain relative positions of the inner and outer pipes and the valves. Inner and outer “vessels,” or “cups,” may comprise components of the cleaners, with the inner cup attaching to the valve near where the valve attaches to the inner pipe. The outer pipe then attaches to the valve at the opposite end, and teeth (serrations) present on spacers on the exterior surface of the inner cup engage serrated openings in the outer cup. Positioned and fixed in this manner, the inner cup may form an annular wall having a lip about which fluid may turn to create the non-linear flow path. 
   It thus is an optional, non-exclusive object of the present invention to provide innovative cleaning devices for fluid-containing vessels. 
   It also is an optional, non-exclusive object of the present invention to provide such devices in the form of automatic cleaners of swimming pools. 
   It further is an optional, non-exclusive object of the present invention to provide automatic swimming pool cleaners with in-line valves and annular gaps into which fluid may flow non-linearly. 
   It additionally is an optional, non-exclusive object of the present invention to provide automatic swimming pool cleaners having shorter pipes than presently used with suction-side cleaners, reducing the ability of associated flexible hoses to steer the cleaners within the pools. 
   It is, moreover, an optional, non-exclusive object of the present invention to provide cleaners with tubular valves shaped, sized, configured, or reinforced differently than existing diaphragms used for similar purposes. 
   It is another optional, non-exclusive object of the present invention to provide cleaners with collapsible segments that assume substantially elliptical internal cross-sectional shapes when collapsed. 
   It is an additional optional, non-exclusive object of the present invention to provide cleaners having valves that may be co-molded with pipes to which they normally attach. 
   It is yet another optional, non-exclusive object of the present invention to provide mechanisms for maintaining relative positions of inner and outer pipes and valves of suction-side automatic swimming pool cleaners. 
   Other objects, features, and advantages will be apparent to those skilled in the art with reference to the remaining text and the drawings of this application. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of an assembly comprising selected components of an automatic pool cleaner consistent with the present invention. 
       FIG. 2  is a top view of an inner cup of the assembly of  FIG. 1 . 
       FIG. 3  is a plan view of portions of the assembly of  FIG. 1 . 
       FIG. 4  is a perspective view of an outer cup of the assembly of  FIG. 1 . 
       FIG. 5  is a plan view of portions of the assembly of  FIG. 1 . 
       FIG. 6  illustrates, in plan view, a valve forming part of the assembly of  FIG. 1 . 
       FIGS. 7-8  are cross-sectional views of the valve of  FIG. 6 . 
       FIG. 9  is an end view of the valve of  FIG. 6 . 
       FIG. 10  is a perspective view of co-molded portions of the assembly of  FIG. 1 . 
       FIG. 11  is a schematicized depiction of an exemplary automatic pool cleaner into which the assembly of  FIG. 1  may be incorporated. 
   

   DETAILED DESCRIPTION 
   A. General Structure 
   Illustrated in  FIG. 1  is assembly  10  adapted principally for use as part of an automatic swimming pool cleaner  12  (see  FIG. 11 ). Included as part of assembly  10  are valve  14 , inner pipe  18 , outer pipe  22 , inner cup  26  and outer cup  30 . Valve  14  includes inlet  34 , flow passage  38  therethrough, and outlet  42 , the latter communicating with inlet  46  of inner pipe  18 . Together, flow passage  38  and inner pipe  18  define a main fluid flow path through the associated automatic pool cleaner  12 . In this respect valve  14  may be said to be “in-line,” as its flow passage  38  forms part of the main flow path of the cleaner. 
   As shown in  FIG. 1 , valve  14  may be connected to inner pipe  18  to ensure fluid communication between valve outlet  42  and inlet  46  of the inner pipe  18 . Near outlet  42 , valve  14  also may be connected to inner cup  26 . While denominated a “cup,” inner cup  26  is in the form of a vessel open at both ends  47  and  48 , instead comprising generally cylindrical wall  50  tapering to shoulder  54 . Inner pipe  18  and part of valve  14  may thus pass through opening  58  ( FIG. 2 ) defined by shoulder  54  before being engaged by shoulder  54  near valve outlet  42 .  FIG. 3  illustrates the result of this engagement, in which the tapering of inner cup  26  helps clamp together valve  14  and inner pipe  18 . 
   Also depicted in  FIGS. 1-3  are longitudinally-oriented spacers  62  protruding from exterior surface  66  of inner cup  26 . In at least one embodiment of assembly  10 , three spacers  62  are positioned approximately one hundred twenty degrees apart around the circumference of wall  50 . Fewer or greater spacers  62  may be used instead, however, and such spacers  62  may be positioned or oriented other than as shown in  FIGS. 1-3 . Each spacer  62  advantageously includes serrations  70  in an area proximate shoulder  54  and end  48 . 
   Near valve inlet  34 , valve  14  may be connected to outer cup  30  which, like inner cup  26 , is in the form of a vessel open at its ends. Outer cup  30 , as illustrated in  FIGS. 4-5 , is designed to fit over portions of wall  50 , with circumferentially-spaced, serrated slots  74  receiving serrations  70  of spacers  62 . This approach permits some initial (or subsequent) adjustment of the position of inner cup  26  relative to outer cup  30  upon application of sufficient force to slide spacers  62  along slots  74 , while maintaining the relative positions of inner and outer cups  26  and  30  absent application of this force.  FIG. 5  illustrates the result of slots  74  having received spacers  62 , while both  FIGS. 4-5  indicate that exterior surface  78  of outer cup  30  also may be threaded so as to include threads  82 . 
   Outer pipe  22 , finally, may be fitted over inner pipe  18 . When outer pipe  22  is so fitted, its internal threads  86  engage threads  82  of outer cup  30  so as to connect outer pipe  22  to outer pipe  30 . An inner tapered portion interfaces with surface  78 , thereby collapsing it inward and causing serrated slots  74  to decrease in width and pinch tightly onto serrations  70  of spacers  62  so as to prevent further axial movement between inner cup  26  and outer cup  30 . The result, as depicted in  FIG. 1 , is assembly  10 , with relative positions of each of valve  14 , inner pipe  18 , outer pipe  22 , inner cup  26 , and outer cup  30  fixed. 
   B. Fluid Flow Paths 
   An automatic pool cleaner  12  utilizing assembly  10  may, like those of the Stoltz and Kallenbach patents, include a body  32  defining one or more fluid inlets  33  and to which a flexible disc D is directly or indirectly attached. Typically, fluid such as swimming pool water with entrained debris will be sucked into the cleaner through the fluid inlets. Thereafter, the debris-laden water will follow main fluid path F into inlet  34  of valve  14 , through passageway  38  to outlet  42 , into inlet  38  of inner pipe  18 , and then through pipe  18  into a flexible hose. 
   Formed, however, within assembly  10  is chamber  90  surrounding valve  14 . Chamber  90  acts in some respects as a reservoir, being filled with water through immersion in a swimming pool of the hose to which assembly  10  is connected. Such filling occurs by water flowing into the hose, through annular gap G 1  between inner and outer pipes  18  and  22 , through annular gap G 2  between inner and outer cups  26  and  30 , and thence into chamber  90 . To facilitate priming of assembly  10 , inner cup  26  may include one or more breather holes  92  to allow rapid evacuation of any air trapped in chamber  90  when initially immersed in water. 
   As the pump to which the hose is connected commences evacuating assembly  10 , at least some water within chamber  90  is sucked back into gaps G 1  and G 2 , which may constitute part or all of a secondary flow path. This action creates a pressure differential between chamber  90  and passageway  38  adequate to cause valve  14  to expand transversely, opening passageway  38  to allow passage of debris-laden water therethrough. Cyclical contraction and expansion of valve  14  thereafter occurs substantially as described in the Stoltz and Kallenbach patents. 
   Whereas the secondary flow paths shown in  FIG. 11  of the Stoltz patent and  FIG. 1  of the Kallenbach patent are effectively wholly linear, that of the present invention need not be. Instead, the secondary flow path has a substantial change of direction, essentially making a “U”-turn of approximately one hundred eighty degrees around lip  94  of wall  50  (as shown by the two-headed arrow in  FIG. 1 ). Because wall  50  is cylindrical (and therefore lip  94  is circular), furthermore, this change of direction occurs throughout the three hundred sixty degrees spanned by the wall  50  and lip  94 . 
   Accordingly, when valve  14  is in a collapsed condition, water or other fluid flowing from chamber  90  thus may travel downward in the depiction of  FIG. 1 , turn about lip  94 , and then may flow upward in the depiction through gap G 2  essentially parallel to its original direction of travel. Thereafter the fluid may make a slight turn within area X identifying the intersection of gaps G 1  and G 2  and resume a course of travel through gap G 1  again essentially parallel to the prior portions of the travel path. When valve  14  is in its open state, water flows back into chamber  90 , again changing direction when encountering lip  94 . 
   Thus, if chamber  90  were the same size as the corresponding chambers of the Stoltz and Kallenbach patents, by the time any particular portion of a water stream would have exited chamber  90  and travelled the length of gap G 2 , it would have travelled a significantly greater distance than to the corresponding points of the cleaners of the Stoltz and Kallenbach patents. Preferably instead, the non-linear secondary flow path of the invention permits chamber  90  to be substantially smaller than the corresponding chambers of the Stoltz and Kallenbach patent while providing an acceptably long secondary path for the water to flow. 
   In use when cleaning the floor of a pool, assembly  10  and both main flow path F and the second flow path through gaps G 1  and G 2  are not typically oriented completely vertically as shown in  FIG. 1 , but rather usually are oriented at an angle between thirty and sixty degrees from the vertical (and often approximately forty-five degrees). Nevertheless, having the non-linear secondary flow path permits decrease in the combined length of outer pipe  22  and chamber  90 . Decreasing the length of rigid components of assembly  10  in turn allows for more random movement of the associated pool cleaner, as it reduces the leverage available to the hose that otherwise would tend to steer or lead the cleaner  12  within the pool. 
   Although the secondary flow path of  FIG. 1  has a non-linearity in the form of a flow reversal, other such non-linearities may be used instead (or in addition). For example, the secondary flow path may be helical or spiral in shape in the area surrounding valve  14 . Alternatively, it may assume a serpentine shape or include one or more curves or turns other than that shown in  FIG. 1 . 
   C. Valves 
   Illustrated in  FIGS. 6-10  is an exemplary valve  14  of the present invention. Valve  14  is designed periodically to interrupt (or at least inhibit or restrict) the flow of fluid through main flow path F, thereby inducing movement of the associated cleaner  12 . Valve  14  preferably, although not necessarily, comprises a generally tubular body made primarily of flexible, elastomeric material. Advantageously, valve  14  is a diaphragm molded principally of a thermoplastic elastomer of thirty to forty Shore A hardness, although it need not be molded or made of this material. 
   Like the valve member described in the Kallenbach patent, valve  14  beneficially includes section  98 , intermediate inlet  34  and outlet  42 , that assumes a substantially collapsed condition absent pressure differential between passageway  38  and exterior  102  of the valve  14 . Additionally similar to the valve member of the Kallenbach patent, section  98  is collapsed transversely. However, unlike the valve member of the Kallenbach patent, whose intermediate segment assumes an essentially rectangular transverse cross-sectional shape when collapsed, section  98  may form a substantially elliptical shape in transverse cross-section, with curved rather than straight bounds. This cross-sectional shape of section  98  is well illustrated in  FIG. 9  and allows greater flow through passageway  38  when section  98  is collapsed (thereby reducing clogging of passageway  38  with debris) without any significant loss of motive power to the cleaner  12 . 
   Also unlike the valve member of the Kallenbach patent, valve  14  may have an upper section  106  rigidized using a material different from that utilized for the remainder of the valve  14 . Depicted especially in  FIG. 8  are a plurality of longitudinal ribs  110  made of the more rigid material of which inner pipe  18  is formed. Also shown in the figure adjacent valve outlet  42  is band  14 , which may extend about the circumference of upper section  105  and interconnect longitudinal ribs  110 . 
   Ribs  110  tend to fan out as section  98  expands; for this reason and because of their lower modulus of flexibility, any or all of ribs  110  (and possibly band  114 ) help prevent collapse of upper section  106  when valve  14  is subject to differential internal and external pressures. Ribs  110  and band  114 , or any of them, additionally may permit the remainder of valve  14  to be made of material softer (i.e. less rigid) than identified in the Kallenbach patent. This new composition of valve  14  requires less energy to open (expand) section  98  and causes the section  98  to open farther than the intermediate segment of the valve member of the Kallenbach patent before returning to its collapsed condition. 
   As noted above, ribs  110  beneficially may be formed of polypropylene or other material different from that from which the remainder of valve  14  is made. Such is not absolutely necessary, though. Instead, ribs  110  could be made of the same material as the remainder of valve  14  but with, perhaps, a greater thickness. Alternatively or additionally, metal or other rigid pins could be placed within or adjacent, or could constitute, ribs  110 . Those skilled in the relevant field will recognize that other means for strengthening upper section  106  may also be employed. 
   Utilizing this construction additionally allows valve  14  to be substantially shorter than the valve member of the Kallenbach patent. A shorter valve  14  complements the fact that chamber  90  may be substantially shorter than the chamber of the Kallenbach patent. Indeed, some versions of valve  14  may be approximately fifty millimeters shorter than existing commercial diaphragm valves for automatic swimming pool cleaners, with a preferred version of valve  14  having a length of one hundred two millimeters and a width of forty-four millimeters. 
   D. Co-Molding 
     FIG. 10 , finally, depicts inner pipe  18  co-molded with valve  14 . Although preferably formed principally of differing materials, inner pipe  18  and valve  14  nevertheless may if desired be molded simultaneously and in a single mold. Such a mold could allow material of inner pipe  18  to flow into link  118  and thence to upper section  106 , forming band  114  and ribs  110 . After the materials of inner pipe  18  and valve  14  are fixed, set, or otherwise hardened into solids, link  118  easily may be removed (as, for example, by being snapped off at points  122  and  126 ). 
   The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments and certain benefits of the present invention. Modifications and adaptations to the illustrated and described embodiments will be apparent to those skilled in the relevant art and may be made without departing from the scope or spirit of the invention.