Patent Publication Number: US-8533874-B1

Title: Pool cleaning system with incremental partial rotating head

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of the earlier U.S. Utility Application to Goettl entitled “Cam Operated Swimming Pool Cleaning Nozzle,” application Ser. No. 12/912,691, filed Oct. 26, 2010, now pending, which is a continuation-in-part application of the earlier U.S. Utility Application to Goettl entitled “Cam Operated Swimming Pool Cleaning Nozzle,” application Ser. No. 12/100,135, filed Apr. 9, 2008, now U.S. Pat. No. 7,819,338, issued Oct. 26, 2010. Application Ser. No. 12/912,691 is also a continuation-in-part of the earlier U.S. Utility Application to Goettl entitled “Cam Operated Swimming Pool Cleaning Nozzle,” application Ser. No. 11/924,400, filed Oct. 25, 2007, now pending, which is a continuation-in-part application of the earlier U.S. Utility Patent Application to Goettl entitled “Method for Operating a Pop-Up Cleaning Nozzle for a Pool or Spa,” application Ser. No. 10/930,494, filed Aug. 31, 2004, now U.S. Pat. No. 7,578,010, issued Aug. 25, 2009, which is a divisional application of a patent application to Goettl entitled “Cam Operated Pop-Up Swimming Pool Cleaning Nozzle filed Apr. 3, 2003, application Ser. No. 10/406,333, now U.S. Pat. No. 6,848,124, issued Feb. 1, 2005, the disclosures of which are hereby incorporated entirely herein by reference. 
     This application is also a continuation-in-part application of the earlier U.S. Utility Application to Goettl entitled “Pool Debris Removal and Design Method,” application Ser. No. 11/926,515, filed Oct. 29, 2007, now pending, which is a continuation-in-part of the earlier U.S. Application to Goettl entitled “Method for Channeling Debris in a Pool,” application Ser. No. 11/675,235, filed Feb. 15, 2007, now abandoned, which is a continuation-in-part application of the earlier U.S. Application to Goettl entitled “Method for Channeling Debris in a Swimming Pool,” application Ser. No. 10/392,606, filed Mar. 19, 2003, now abandoned, the disclosure of which is hereby incorporated entirely herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     Aspects of this document relate generally to cleaning nozzles for swimming pools and pool cleaning systems. 
     2. Background Art 
     Pool cleaning systems are used in swimming pools to remove dirt and debris from the water in the swimming pool. Various methods for removing debris from the pool include the use of “whips” extending from various location on the side walls or nozzles in the side walls or floor surface to stir up debris for pumping to the pool filter. Conventional cleaning nozzles for swimming pools utilize water pressure generated by a pool pump to direct a stream of water across a surface of the pool to entrain and move contaminants from the surface toward a drain. Many conventional cleaning nozzles “pop up” from a surface of a pool as the heads, normally level with the surface, are extended under the influence of water pressure from the pump. When the water pressure from the pump ends, the heads retract downward until level with the surface, conventionally in response to bias from a spring element contained within the cleaning nozzle. 
     SUMMARY 
     Implementations of a pool cleaning system having a plurality of incrementally rotating pool cleaning head assemblies on a floor of a pool may comprise at least one debris capture point in the pool, at least one first cleaning head assembly on the floor of the pool, and at least one second cleaning head assembly on the floor of the pool between the at least one debris capture point and the at least one first cleaning head assembly and comprising a incremental rotation and a net water flow vector in the direction of the debris capture point, wherein the at least one second incrementally rotating cleaning head assembly may comprise a cam assembly comprising an upper section, a lower section, and a rotatable section slidably disposed between the upper section and the lower section and rotatable in relation to the upper section and the lower section between a first extent and a second extent, each of the upper section and the lower section comprising a plurality of saw tooth members, and a stem extending through the cam assembly and comprising a pin slidably engaged with the plurality of saw tooth members, the pin configured to incrementally rotate the stem clockwise in intermittent contact with the saw tooth members and the rotatable section of the cam assembly during a vertical translation of the stem through intermittent application of water pressure force, and to slidably rotate the rotatable section of the cam assembly from its first extent to its second extent, and wherein the cam assembly is configured to automatically reverse the incremental rotation of the stem to counterclockwise when the rotatable section of the cam assembly is rotated to its second extent. 
     Particular implementations of a pool cleaning system may comprise one or more of the following features. The upper section and the lower section of the cam assembly may be coupled in a positionally fixed manner such that they do not rotate with respect to each other. The upper section and the lower section of the cam assembly may be coupled in a positionally fixed manner through a locking ring comprising a plurality of lugs mechanically engaged with a cam housing. The locking ring may further comprise an annular surface comprising at least one angled projection extending toward a cap ring rotationally coupled to the cam housing, the cap ring comprising raised projections on an annular surface extending toward the locking ring, wherein rotation of the cap ring in relation to the locking ring causes the raised projections on the cap ring to engage the angled projections on the locking ring to resist rotational movement of the cap ring in one direction. The pool cleaning system may further comprise a cap ring removably coupled to the cam housing over the locking ring, the cam housing further comprising a locking arm extending from a side of the cam housing, flexibly engaging the cap ring and resisting rotational movement of the cap ring in one direction. The pool cleaning system may further comprise a plurality of ridges on an annular surface of a cam housing, the lower section of the cam assembly comprising a plurality of mating grooves on an annular surface of the lower section of the cam assembly, wherein coupling the plurality of ridges of the cam housing with the plurality of grooves of the cam assembly resists rotational movement of the cam assembly within the cam housing. 
     A pool cleaning system having a plurality of incrementally rotating pool cleaning head assemblies on a floor of a pool may comprise at least one debris capture point in the pool, at least one first cleaning head assembly on the floor of the pool, at least one second cleaning head assembly on the floor of the pool between the at least one debris capture point and the at least one first cleaning head assembly and comprising a incremental rotation and a net water flow vector in the direction of the debris capture point, wherein the at least one second incrementally rotating cleaning head assembly comprises a cam assembly having an upper section, a lower section, and slidable section rotatably disposed between the upper section and the lower section, and a stem, and wherein the stem comprises an outlet configured to eject an intermittent stream of water under water therethrough under water pressure force, the stem extending through the cam assembly, the stem further comprising at least one pin slidably engaged with the cam assembly and configured to intermittently engage with a saw tooth member within the upper section and slidable section and to slidably rotate the slidable section with the stem is under water pressure force. 
     Particular implementations of a pool cleaning system may comprise one or more of the following features. The slidable section may comprise a channel in communication with an angled channel comprised in the upper section, and the slidable section is configured to accommodate through slidable rotation, the pin, as it enters the channel. The pool cleaning system may further comprise a locking ring mechanically engaged with cam housing, the locking ring further comprising an annular surface comprising at least one angled projection extending toward a cap ring rotationally coupled to the cam housing, the cap ring comprising raised projections on an annular surface extending toward the locking ring, wherein rotation of the cap ring in relation to the locking ring causes the raised projections on the cap ring to engage the angled projections on the locking ring to resist rotational movement of the cap ring in one direction. The pool cleaning system may further comprise a plurality of ridges on an annular surface of the cam housing and a plurality of grooves on an annular surface of the cam assembly that mate with the plurality of ridges on the cam housing when removably coupled thereto and resist rotational movement of the cam assembly within the cam housing; wherein the cam assembly is configured to both incrementally rotate the stem clockwise as the stem extends from the housing under water pressure force and to automatically reverse the incremental rotation of the stem counterclockwise. The pool cleaning system may further comprise a cap ring removably coupled to the cam housing over a locking ring engaged with the cam housing, the cam housing further comprising a locking arm extending from a side of the cam housing, flexibly engaging the cap ring and preventing rotational movement of the cap ring in one direction. 
     A swimming pool cleaning system having a plurality of cleaning nozzle assemblies for ejecting streams of water to clean of a swimming pool may comprise at least one debris capture zone in the swimming pool, at least one first cleaning nozzle assembly on a surface of the swimming pool, at least one second cleaning nozzle assembly on the surface of the swimming pool between the at least one debris capture zone and the at least one first cleaning nozzle assembly and comprising an incremental rotation and a net water flow vector in the direction of the debris capture zone, wherein the at least one second cleaning nozzle assembly comprises: a housing comprising a cam assembly having an upper section, a lower section, and a slidable section rotatably disposed between the upper section and the lower section, and a stem comprising an outlet configured to eject an intermittent stream of water under water therethrough under water pressure force, the stem extending through the cam assembly, the stem comprising at least one pin slidably engaged within the cam assembly. 
     Particular implementations of a swimming pool cleaning system may comprise one or more of the following features. The at least one pin may be configured to intermittently engage with a saw tooth member comprised within the upper section and slidable section and to slidably rotate the slidable section while the stem is under water pressure force. The slidable section may comprise a channel in communication with an angled channel comprised in the upper section, and the slidable section is configured to accommodate through slidable rotation, the pin, as it enters the channel. The swimming pool cleaning system may further comprise a locking ring mechanically engaged with the cam housing, the locking ring further comprising an annular surface comprising at least one angled projection extending toward a cap ring rotationally coupled to the cam housing, the cap ring comprising raised projections on an annular surface extending toward the locking ring, wherein rotation of the cap ring in relation to the locking ring causes the raised projections on the cap ring to engage the angled projections on the locking ring to resist rotational movement of the cap ring in one direction. The swimming pool cleaning system may further comprise a plurality of ridges on an annular surface of the cam housing and a plurality of grooves on an annular surface of the cam assembly that mate with the plurality of ridges on the cam housing when removably coupled thereto and resist rotational movement of the cam assembly within the cam housing; wherein the cam assembly is configured to both incrementally rotate the stem clockwise as the stem extends from the housing under water pressure force and to automatically reverse the incremental rotation of the stem counterclockwise. The swimming pool cleaning system may further comprise a cap ring removably coupled to the cam housing over a locking ring engaged with the cam housing, the cam housing further comprising a locking arm extending from a side of the cam housing, flexibly engaging the cap ring and preventing rotational movement of the cap ring in one direction. The swimming pool cleaning system may further comprise a pattern cam coupled to the cam assembly and operably coupled with the slideable section such that the slideable section is moved from a first position to a second position when the pattern cam reaches a first extent. The first cleaning nozzle assembly may be associated with a first pool cleaning head circuit of a plurality of pool cleaning head circuits, and wherein the pool cleaning system cycles sequentially through the plurality of pool cleaning head circuits so the first pool cleaning head circuit is temporarily on during its portion of the cycle and off for the balance of the cycle. The second cleaning nozzle assembly may be a transition head comprising a total effective area and wherein a majority of the total effective area is in a direction facing more toward the debris capture zone than to an origin head. 
     The foregoing and other aspects, features, and advantages will be apparent to those artisans of ordinary skill in the art from the DESCRIPTION and DRAWINGS, and from the CLAIMS. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and: 
         FIG. 1  is an perspective view of a nozzle assembly; 
         FIG. 2  is a cross sectional view of the nozzle assembly shown in the retracted position; 
         FIG. 3  is a cross sectional view taken along lines  3 - 3  shown in  FIG. 2 ; 
         FIG. 4  is a cross sectional view taken along lines  4 - 4  shown in  FIG. 2 ; 
         FIG. 5  is a cross sectional view of the nozzle assembly in the extended position; 
         FIG. 6  is an exploded view of a nozzle assembly; 
         FIG. 6A  is a side view of the pattern come shown in  FIG. 6 ; 
         FIG. 7  illustrates the travel path of a pin through the cam while incrementally rotating the nozzle assembly; 
         FIG. 8  illustrates the travel path of the pin through an alternative cam while incrementally rotating the nozzle assembly; 
         FIG. 9  is an exploded view of an implementation of a nozzle assembly; 
         FIG. 10  is a cross-sectional view of an assembled nozzle assembly along sectional line A in  FIG. 9 . 
         FIG. 11  illustrates the travel path of a pin through the cam of an implementation of a nozzle assembly during intermittent rotation clockwise; 
         FIG. 12  illustrates the travel path of a pin through the cam of an implementation of a nozzle assembly indicating the movement of the slidable section of the cam followed by intermittent rotation counterclockwise; 
         FIG. 13  is a flow diagram of the steps of a method of cleaning a swimming pool utilized by particular implementations of swimming pool cleaning heads; 
         FIG. 14  is a flow diagram of an implementation of a method of adjusting a swimming pool cleaning head; and 
         FIG. 15  is a cross-sectional view of an assembled nozzle assembly similar to that of  FIG. 10 , but in an extended position. 
         FIG. 16  is an illustration of the flow emanating from a conventional continuous rotation cleaning head; 
         FIG. 17  is an illustration of the flow emanating from a conventional incremental rotation cleaning head; 
         FIG. 18  is a cross sectional view of a conventional pool with a cleaning system block diagram comprising cycling cleaning head circuits; 
         FIG. 19  is a plan view of three differently sized conventional pools illustrating cleaning head placement and conventional operation; 
         FIG. 20  is a plan view of a conventional diving pool illustrating conventional cleaning head placement and operation; 
         FIG. 21  is a plan view of a conventional lap pool illustrating conventional cleaning head placement and operation; 
         FIG. 22  is a plan view of a conventional floor cleaning head placed near a corner of a pool illustrating conventional cleaning head placement and operation in relation to debris movement; 
         FIG. 23  illustrates different configurations of flow vectors for a pool cleaning head; 
         FIG. 24  illustrates a symbol for a pool cleaning head used to emphasize that the net flow vector for the cleaning head is not neutral. 
         FIG. 25  is a plan view of a small diving pool illustrating cleaning head placement and operation according to a basic implementation of a pool cleaning system; 
         FIG. 26  is a plan view of implementations of a small play pool (A), a lap pool (B), and a larger play pool (C) illustrating cleaning head placement and operation according to particular implementations of a pool cleaning system; 
         FIG. 27  is a plan view of a very large pool implementation illustrating cleaning head placement and operation according to a particular implementation of a pool cleaning system; 
         FIG. 28  is a plan view of a pool implementation having outside corners illustrating cleaning head placement and operation according to a particular implementation of a pool cleaning system; 
         FIG. 29  is a plan view of a more complicated pool implementation having multiple capture zones illustrating cleaning head placement and operation according to a particular implementation of a pool cleaning system; 
         FIG. 30  is a plan view of another complicated pool implementation illustrating cleaning head placement and operation according to a particular implementation of a pool cleaning system; 
         FIG. 31  is a plan view of yet another complicated pool implementation illustrating cleaning head placement and operation according to a particular implementation of a pool cleaning system; 
         FIG. 32  is a flow diagram of a first method of designing a pool cleaning system; 
         FIG. 33  is a flow diagram of a second method of designing a pool cleaning system; and 
         FIG. 34  is a plan view of a swimming pool illustrating cleaning head placement and operation of a pool cleaning system. 
     
    
    
     DESCRIPTION 
     This disclosure, its aspects and implementations, are not limited to the specific components or assembly procedures disclosed herein. Many additional components and assembly procedures known in the art consistent with the intended nozzle assembly and/or assembly procedures for a nozzle assembly will become apparent for use with particular implementations from this disclosure. Accordingly, for example, although particular implementations are disclosed, such implementations and implementing components may comprise any shape, size, style, type, model, version, measurement, concentration, material, quantity, and/or the like as is known in the art for such nozzle assemblies and implementing components, consistent with the intended operation. 
     A particular implementation of a recessed incrementally rotating nozzle assembly  10  for use in swimming pools and the like is illustrated in  FIG. 1 . In the retracted position, the upper surface of the nozzle assembly is substantially flush with the adjacent swimming pool surface. The extended position of nozzle housing  12  is shown in dashed lines and includes an outlet  14  through which a stream of water is ejected. Body  16  includes a hollow cylinder  18  for attachment to the interior of a conduit  20  (see  FIG. 2 ) periodically supplying water under pressure to the nozzle assembly. 
     A diametrically enlarged section  22  is supported by and extends from cylinder  18 . Referring to the implementation illustrated in  FIG. 2 , cylinder  18  includes a plurality of lugs  30  disposed on the interior surface thereof. A retainer  32 , for retaining the operative elements of the nozzle assembly within body  16  (alternatively called a housing in this disclosure), includes a plurality of lugs  34  extending radially outwardly for locking engagement with lugs  30  upon passing the lugs  34  of the retainer  32  axially past the lugs  30  of cylinder  18  and rotating the retainer  32  to bring about locking engagement. In particular implementations, an O-ring  36  or the like may be disposed between the retainer and the cylinder to prevent water flow therebetween. 
     A cam assembly comprises a cam ring  40  and a cam reverser  50 . The cam ring  40  is rotatably lodged within radially expanded section  42  of retainer  32 . Rotation of the cam ring  40  relative to section  42  is prevented by a screw  44 , or the like, threadedly inserted between cam ring  40  and section  42 . A plurality of downwardly pointing saw tooth members  46 , or other pin guides  46 , are disposed along the upper part, or upper section, of cam ring  40 . A similar plurality of upwardly pointing saw tooth members  48 , or other pin guides  48 , are disposed along a lower part, or lower section, of cam ring  40 . A ring-like cam reverser  50  is slidably lodged adjacent cam ring  40  and is circumferentially slidably captured between the upper section and lower section saw tooth members  46 ,  48  between a first position or extent and a second position or extent. An arm  52  extends downwardly and radially inwardly from the cam reverser  50 . Further details relating to the structure and operation of implementations of the saw tooth members  46 ,  48 , the cam reverser  50 , and the arm  52  will be described later in greater detail. 
     A sleeve or stem  60  is vertically translatable upwardly within cylinder  18  in response to water pressure present within conduit  20 . Such vertical translation is resisted by a coil spring  62  bearing against an annular lip  64  of the sleeve  60 , a lip  81  associated with a pattern cam  80 , and the retainer  32 . Nozzle housing  12  is supported upon sleeve  60  and defines an outlet  14  through which a stream of water is ejected upon upward translation of the sleeve  60 . In the absence of water pressure within conduit  20 , coil spring  62  will draw sleeve  60  and nozzle assembly  12  downwardly to the retracted position illustrated in  FIG. 2 . A pair of diametrically opposed pins  70 , 72  extend radially outwardly from nozzle housing  12  for sliding engagement with sets of saw tooth members  46 ,  48 , which engagement causes nozzle housing  12  to rotate incrementally each time it is extended and refracted under the influence of water pressure, as will be described in further detail below. In particular implementations, only a single pin  70  or  72  may be used. Equivalently, the saw tooth members  46 ,  48  could be positioned on the sleeve or stem and the cam ring  40  could comprise the pin or pins  70  or  72  to enable reciprocating incremental movement of the cam ring in relation to the stem. 
     A pattern cam  80  is positionally fixed upon radially extending shoulder  38  formed as part of retainer  32  (also called the cam assembly). It includes lip  81  extending around the interior edge of shoulder  38 . The pattern cam  80  is configured to determine the angular extent of reciprocating rotation of nozzle housing  12 . Particular implementations of a pattern cam  80  may define an angle of reciprocating rotation of 180 degrees or ninety degrees; however, for implementations utilized in specific locations within a swimming pool, a greater or lesser angle of reciprocating rotation may be selected to ensure washing/scrubbing of the swimming pool surface of interest. 
     Referring to  FIGS. 3 ,  6  and  6 A, an implementation of a pattern cam  80  is illustrated. Sleeve  60  includes a keyway  68  to serve in the manner of an index. Pattern cam  80  includes an annular arc  84  extending from semi-circular disc  82 , the combination of which surrounds sleeve  60 . Annular arc  84  includes a key  86  mating with keyway  68  of sleeve  60 ; thereby, the pattern cam  80  is indexed with the sleeve  60  and will rotate commensurate with nozzle housing  12 , also fixedly attached to the sleeve. Arm  52  is terminated by a flat roundel  54  disposed in the horizontal plane of disc  82 . As sleeve  60  rotates in response to pins  70 ,  72  sequentially contacting saw tooth members  46 ,  48 , pattern cam  80  will rotate commensurately. When one of edges  88 ,  89  of disc  82 , such as edge  89 , contacts roundel  54  as the disc rotates in, for instance, a counterclockwise direction as viewed in  FIG. 3 , the force of edge  89  acting upon roundel  54  will cause the roundel  54 , arm  52 , and cam reverser  50  (also sometimes called a slideable section) to be repositioned incrementally from a first position to a second position counter clockwise as a function of the spacing between adjacent saw tooth members  46 , 48  (see  FIG. 2 ). The resulting repositioning of the cam reverser results in a change in direction of rotation of sleeve  60  along with attached nozzle housing  12 . On the completion of incremental steps of rotation in the counter clockwise direction, edge  88  of disc  82  will contact the other side of roundel  54  and cause it to be translated incrementally clockwise. Such translation of the roundel  54  is translated via arm  52  to cam reverser  50  and the rotation of sleeve  60  and nozzle housing  12  will change direction. 
       FIG. 4  primarily illustrates lugs  34  of retainer  32  in engagement with lugs  30  of cylinder  18 , all of which are disposed within conduit  20 . 
       FIG. 5  illustrates a particular implementation of a nozzle housing  12  in the extended position. In this condition, water pressure exists within conduit  20  and causes sleeve  60  to be raised against the bias supplied by coil spring  62 . As the sleeve  60  rises, it causes nozzle housing  12  to rise, as illustrated. As the nozzle housing  12  rises, pins  70 ,  72  rise in the spaces formed by the edges of intermediate saw tooth members  46 . Because the pins  70 , 72  bear against the edges of saw tooth members  46 , which are slanted opposed sides, the pins  70 , 72  are angularly translated about the vertical axis of nozzle  10 , rotating nozzle housing  12  incrementally a corresponding angular distance. When water pressure within conduit  20  is terminated, the bias supplied by coil spring  62  will cause sleeve  60  to retract and the nozzle housing  12  will be lowered within section  22 , as shown in  FIGS. 1 and 2 . As nozzle housing  12  is lowered, pins  70 ,  72  contact the edges of saw tooth members  48  and angularly translate once again, rotating the nozzle housing  12  incrementally a corresponding angular distance. The direction of rotation (clockwise or counterclockwise) is controlled by cam reverser  50  and will be described in further detail with reference to  FIGS. 7 and 8 . 
       FIG. 6  illustrates an exploded view of the primary components of a particular implementation of a nozzle assembly  10  and  FIG. 6A  illustrates an implementation of a pattern cam  80  in more detail. As illustrated, sleeve  60  may include lugs  90 ,  92  cooperating with corresponding lugs in nozzle housing  12  to function similarly to a bayonet fitting and lock the sleeve  60  with the housing  12 . Upon locking, the outlet  94  of the sleeve  60  may be oriented with either of diametrically opposed outlets  14 ,  14 A in nozzle housing  12 . 
     A disc  96  may be centrally located in the top of the nozzle housing  12  to close opening  98 , that is formed primarily for manufacturing purposes. The disc  96  may include opposed lugs  100 ,  102  which slidably engage corresponding opposed slots, of which slot  104  is shown. A lip  106  is disposed at the top of each of the slots  104  to prevent ejection of disc  96 . The four sets of channels  108  illustrated in the particular implementation of a nozzle housing  12  may have no functional purpose and may be employed primarily for manufacturing reasons to minimize the thickness of the plastic of the nozzle housing and avoid shrinkage after manufacture. In the implementation illustrated, pattern cam  80  includes a disc  82  representing approximately 180 degrees between edges  88 ,  89 , which disc controls the angular excursion of nozzle housing  12 . However, the angular excursion can be easily reduced to 90 degrees or set to any other value by simply substituting another pattern cam  80  having an annular extension such that the angular distance between edges  88 ,  89  corresponds with the angular rotation wanted of for the nozzle housing  12 . 
     Referring to  FIG. 7 , the incremental rotation, automatic reversal, and subsequent incremental rotation of a particular implementation of a nozzle housing  12  is illustrated. Saw tooth members  46 , located on cam ring  40 , are representatively illustrated along with saw tooth members  48  also mounted upon the cam ring  40 . Cam reverser  50  includes a series of upper triangularly shaped protrusions  110 , or other upper pin guides  110 , pointed downwardly (see also  FIG. 2 ) and a plurality of lower triangularly shaped protrusions  112 , or other lower pin guides  112 . One of pins  70 ,  72  is represented by a roundel having therein either a symbol of V or A. The symbol V represents downward movement of the pin and the symbol A represents upward movement of the pin. When sleeve  60  is forced upwardly by water pressure within conduit  20 , nozzle housing  12  and pins  70 ,  72  extending therefrom will travel upwardly, as represented by arrow  114 , from in-between the junction of two adjacent saw tooth members  48 , as depicted on the left side of  FIG. 7 . 
     Upon upward movement, the pin(s)  70 ,  72  will strike protrusion  110  and be deflected to the right, or in the clockwise direction, as indicated. Such deflection will incrementally rotate nozzle housing  12  clockwise. After the pin(s)  70 ,  72  passes protrusion  110 , it will be guided to the right by the edge of saw tooth member  46  until it reaches the junction between adjacent saw tooth members  46 . In particular implementations, the degree of rotation of nozzle housing  12  may be commensurate with the angular distance between the junction between adjacent saw tooth members  48  and the junction between adjacent saw tooth members  46 . After water pressure within conduit  20  ceases, coil spring  62  causes retraction of sleeve  60  and nozzle housing  12 . During such retraction, the pin(s)  70 , 72  moves vertically downwardly, as represented by arrow  116 , until it strikes an edge of protrusion  112 . This protrusion  112  will guide the pin  70 , 72  adjacent an edge of saw tooth members  48  until it comes to rest at the junction between the two adjacent saw tooth members  48 . 
     In particular implementations, saw tooth members  46  may be offset from saw tooth members  48  by one-half of the width of the saw tooth members  46 ,  48 , when saw tooth members  46 ,  48  have substantially identical dimensions. In other particular implementations, the degree of rotation of the nozzle housing  12  during each incremental rotation step may be governed by the dissimilarly between the relative dimensions of the saw tooth members  46 ,  48 , e.g., the nozzle housing  12  may rotate more on its way down rather than on its way up. 
     As nozzle housing  12  rotates, sleeve  60  will rotate commensurately. Such rotation of the sleeve will cause pattern cam  80  (see  FIG. 3 ) to rotate until one of edges  88 ,  89  contacts roundel  54  and causes the roundel  54  to move angularly. Such angular movement of roundel  54  is translated to commensurate rotational (angular) movement of cam reverser  50 . The angular displacement of the cam reverser  50  is depicted and represented by protrusion  118  shown in dashed lines to indicate movement of each of protrusions  112  (and protrusions  110 ). The resulting relationship between protrusions  110 ,  112  and saw tooth members  46 ,  48  is depicted in the right half of  FIG. 7 . 
     As illustrated, the pin(s)  70 ,  72  will move upwardly from in between saw tooth members  48  commensurate with upward movement of nozzle housing  12  upon the presence of water pressure within conduit  20 . As the pin  70 ,  72  moves upwardly, it will contact protrusion  110  and be directed to the left, or counterclockwise, (not to the right as formerly described). Thereafter, the pin(s)  70 ,  72  will slide along the edge of saw tooth members  46  until reaching the junction between adjacent saw tooth members  46 . Upon cessation of water pressure within conduit  20 , sleeve  60  and nozzle housing  12  will retract and the pin(s)  70 ,  72  will move until it strikes the edge of protrusion  112 . This edge will guide the pin(s)  70 ,  72  onto the edge of a saw tooth member  48  until it bottoms out at the junction between adjacent saw tooth members  48 ; this position corresponds with the retracted position of sleeve  60  and nozzle housing  12 . The resulting incremental rotation of nozzle housing  12  will continue until the other edge of cam pattern  80  contacts and causes rotational movement of roundel  54  to relocate the cam reverser  50 . 
     To limit the rotational movement of cam reverser  50 , a tab  120  extends from retainer  32  into penetrable engagement with a slot  122  formed in cam reverser  50 . The movement of the slot  122  with respect to the tab  120  controls the degree of angular excursion of the cam reverser  50  each time the rotational movement is changed; furthermore, the movement of the slot  122  from one side to the other precisely controls the repositioning of protrusions  110 ,  112  to ensure alignment with the respective saw tooth members  46 ,  48  and thereby accurately directs the engaging pin  70 , 72  to the corresponding edge of the respective saw tooth member  46 ,  48 . 
     Referring to  FIG. 8 , another particular implementation of saw tooth members and protrusions  110 A and  112 A is illustrated. Protrusions  110 A and  112 A are generally adjacent one another whereby the tip of one protrusion  110 A,  112 A is essentially horizontally aligned with the base of an adjacent protrusion  110 A,  112 A. Such arrangement may provide a greater degree of guidance for the pin(s)  70 ,  72  as they move up and down adjacent the protrusions  110 A,  112 A and into the junctions between upper and lower adjacent saw tooth members. Other than these structural distinctions, implementations like those illustrated in  FIG. 8  function and operate similarly to those illustrated and described with reference to  FIG. 7 . 
     It may be noted that the degree of total angular rotation of nozzle housing  12  is, as stated above, a function of the angular extent of disc  82  between edges  88 ,  89  of pattern cam  80 . To change the degree of total angular rotation excursion of nozzle housing  12 , an existing pattern cam  80  may be readily substituted with another pattern cam having an angularly differently configured disc  82  to increase or decrease the amount of total angular rotation of the nozzle housing  12 . 
     In the past, the orientation of a stream of water emanating from a nozzle was set by carefully aligning the nozzle assembly as a whole in the desired direction. Such alignment was generally semi-permanent and adjustment was usually quite difficult. Because of such difficulty, workmen tended to have the attitude that “close enough was good enough”. Unfortunately, the cleaning capability was usually compromised. With implementations of nozzle assemblies  10 , adjustment can be more readily and easily made by loosening screw  44  (see  FIGS. 1 and 2 ) and rotating cam ring  40  until the water stream is ejected precisely to the area of interest. To set the cam ring  40  in this new position, screw  44  is tightened. 
     Structure. 
     Referring to  FIG. 9 , an exploded view of another implementation of a cleaning head assembly (alternatively called a nozzle assembly)  124  is illustrated. The cleaning head assembly  124  may include a cam assembly (alternatively called a cam ring)  126 . As illustrated, in particular implementations the cam assembly  126  may include an upper section  128 , a slidable section  131  (alternatively called a cam reverser), and a lower section  130 . The slidable section  131  may include at least one shifter  129  that extends from the slidable section into the upper section  128 . The cam assembly  126  may couple into a housing (alternatively called a body)  132 . When coupled into the housing  132 , a locking ring  134  may be coupled over the lower section  130  and includes lugs  135  that engage within locking features  137  in the housing  132 . In particular implementations, the upper section  128  and lower section  130  of the cam assembly  126  may be fixedly coupled together through, by non-limiting example, a sonic weld, heat staking, adhesive or other method of fixedly coupling two plastic parts together. While the upper section  128  and lower section  130  are fixedly coupled together, the slidable section  131  remains slidably engaged between them and is free to move rotatably with respect to the upper and lower sections  128 ,  130 , respectively. 
     The tips of the lugs  135 , of the particular implementation shown in  FIG. 9 , are configured with prongs  200  that fit into the recesses  202  of the locking features  137  in the housing  132 . Placement of the locking ring  134  over the cam assembly  126  in the lower section  130  holds the cam assembly  126  in place through mating of the prongs  200  with the recesses  202 . In many cases, the strength of the engagement of the prongs  200  into the recesses  202  is strong enough that the up and down nozzle action in the cam assembly  126  so that the nozzle  140  may be tested without the cap ring  136  added. This allows an installer to rotationally adjust the cam assembly  126  in relation to the lower section  130  prior to locking all of the components in place with the cap ring  136 . By rotationally adjusting the cam assembly  126  in relation to the lower section  130 , the directional orientation of the nozzle  140  may be set regardless of the original orientation of the in-wall fitting for the nozzle assembly. In other words, even though the in-wall fitting for the nozzle assembly yields an unknown radial direction for the final nozzle housing, an installer can adjust the direction of the nozzle during installation to any orientation needed. 
     A cap ring  136  may be coupled over the cam assembly  126  against the locking ring  134 . Use of the cap ring  136  may allow, in particular implementations, for the lower and upper sections  130 ,  128  of the cam assembly  126  to be rendered substantially immobile in relation to the housing  132  during operation of the cleaning head assembly  124  while leaving the slidable section  131  capable of rotational sliding motion. The cap ring  136  may be loosened or removed by pressing a locking arm  204  coupled to the housing  132  which is engaged with the cap ring  136  inwardly through an opening  206  in the cap ring  136  until the locking arm  204  disengages from the cap ring  136 . The locking arm  204  is biased to a position that engages the cap ring  136 . For example, the locking arm  204  may be formed of a flexible material that self-biases the locking arm  204 . As another example, the locking arm  204  may be formed as a lever with a spring, or through other structures known in the art for manufacturing a biased arm. 
     As illustrated in  FIG. 9 , the ability of the cap ring  136  to render the lower and upper sections  128 ,  130  of the cam assembly  126  substantially immobile is aided, in particular implementations, by a plurality of ridges  208  distributed along the surface of the housing  132  that couple with the lower section  130  of the cam assembly  126 . As illustrated, the lower section  130  includes a plurality of grooves  210  that couple with the plurality of ridges  208  of the housing  132  under compressive force created by the rotation of the cap ring  136 . In particular implementations, the compressive force generated by the rotation of the cap ring  136  may be increased through a plurality of ramp members  212  extending from the locking ring  134  that engage with projections  214  of the cap ring  136  while it is rotated. As the cap ring  136  is rotated, the force on the locking ring  134  increases as the projections  214  engage with the ramp members  212 , pressing the locking ring  134  against the lower section  130  of the cam assembly  126 . As the force against the lower section  130  increases, the plurality of grooves  210  begin to increasingly engage with the plurality of ridges  208 , thereby increasingly restricting the rotational motion of the lower section  130  until it is rendered substantially immobile. In particular implementations, once the cap ring  136  has been rotated sufficiently to render the lower section  130  immobile, the locking arm  204  may engage with the cap ring  136  to prevent any unintentional loosening of the cleaning head assembly  124  thereby maintaining the positional relationship between the cam assembly  126  and the housing  132 . 
     As illustrated in  FIG. 9 , implementations of a cleaning head assembly  124  may include a stem (sleeve)  140  that extends through the housing  132  and the cam assembly  126 . In the particular implementation illustrated in  FIG. 9 , the stem  140  comprises at least one pin  142  that extends from a side of a head  150  (nozzle housing) that couples over the top of the stem  140 . In other implementations, the at least one pin  142  may couple to other components associated with the stem  140  so that in either case (whether extending from the side of the head  150  or from some other component associated with the stem  140  or from the stem directly), the at least one pin  142  can be said to extend from the stem  140 . In particular implementations of a stem  140 , two or more pins  142  may be included, and the relation between the direction the pin  142  extends from the side of the stem  140  relative to the outlet  144  may range from about parallel to about perpendicular, depending upon system requirements. The pin  142  for these implementations engages with the cam assembly  124  within the upper section  128 , the slidable section  131 , and the lower section  130 , as illustrated in  FIG. 10 . In particular implementations, the pin  142  may contact the edges of a plurality of saw teeth  146  within the cam assembly  126 . The stem  140  may further include a spring element (coil spring)  148  (shown on  FIG. 10 ) configured to provide bias force against the stem  140  when it is extended from the housing  132 .  FIG. 15  illustrates the cleaning head assembly  216  in an extended position, where the outlet  218  is raised above an upper surface of the cap ring  220  and the pin  142  is engaged against a surface of the saw teeth  220  in the upper section  6  of the cam assembly  222 . In the extended position, the stem  224  is raised by water pressure force against the bias of the spring element  148 .  FIG. 15  also illustrates a swimming pool wall  226  with a threaded fitting  228  mounted in the wall. The cleaning head assembly  216  threadedly mates with the threaded fitting  228  in this implementation. Other coupling types are known four coupling a cleaning head assembly to a wall fitting and may equivalently be used in place of the threaded fitting shown here. 
     Use. 
     Referring to  FIG. 15 , an illustration of the interior of a cam assembly (example as cam assembly  126  in  FIG. 9 ) for a cleaning head assembly (example as cleaning head assembly  124  in  FIG. 9 ) is shown with reference to the particular implementation of  FIG. 9  as an example. As illustrated, the edges of the saw teeth  152 ,  154 ,  156 , or other guides  152 ,  154 ,  156 , of the upper section  128  and slidable section  131  of the cam assembly  126  form a plurality of channels  158 ,  160 ,  162  in which a pin  142  travels during operation of a cleaning head assembly  124 . For ease of understanding, slidable section  131  has been marked in  FIGS. 11 and 12  with right downwardly sloping hatch marks. The pin  142  has been marked with right upwardly sloping hatch marks. Although the FIGs. Show more than one pin  142 , this is intended to be illustrative of the movement of the pin  142  from one end of a channel to another end and not necessarily that there are two pins  142  in the particular implementation. 
     During operation of the cleaning head assembly, water pressure force is intermittently exerted on the stem  140 , forcing it to extend upwardly. As the stem  140  moves upwardly, the pin  142  also travels upwardly in a first channel  158  formed to a side of the edges of the saw teeth  152 ,  154 . It should be understood that in its ordinary rest position, the pin  142  would not be in the upper position (as  142   a ) between tooth  152  of the upper cam  128  and the shifter  129 , but would be resting within the lower cam section  130 . When the water pressure force is removed, the bias of the spring element  148  withdraws the stem  140  into the housing  132  (see  FIG. 9 ). As the stem  140  withdraws, the pin  142  travels downwardly through the first channel  158  (as indicated by the arrow  164 ). In the process, the rotational position of the stem  140  may travel incrementally clockwise (or counterclockwise depending upon the direction of movement for the stem). When the intermittent water pressure force is once again exerted on the stem  140 , the pin  142  travels upwardly between the saw teeth  154 ,  156  into the second channel  160 , as indicated by the arrow  168 . Once again, the rotational position of the stem  140  may continue to move incrementally clockwise (or counterclockwise) until it rests in the position illustrated in  FIG. 12  as pin  142   d . It should be noted that when the pin  142   d  initially comes to rest in the position illustrated in  FIG. 12 , the slidable section  131  (and integral shifter  129 ) is still in its position to the left illustrated in  FIG. 12 . 
     Referring to  FIG. 12 , as the water pressure force is again removed from the stem  140 , the bias of the spring element  148  draws the stem  140  (see  FIG. 9 ) downward again, causing the pin  142  to travel between saw teeth  156 ,  154 , further moving the rotational position of the stem  140  incrementally clockwise (or counterclockwise). By repeating the intermittent application and removal of water pressure force, stem  140  rotate until the pin  142  enters the third channel  162 , as indicated by arrow  170  ( FIG. 12  in a first slidable section position and  FIG. 13  illustrating a second slidable section position) for as many channels the cam assembly includes until it reaches the limits of the cam rotation. For the implementation shown in  FIGS. 12 and 13 , the implementation includes only four channels  158 ,  230 ,  160  and  162 . 
     After the pin  142   d  is positioned at the start of the final channel  162 , with the shifter  129  in its position illustrated in  FIG. 12 , water pressure force is exerted on the stem  140  and the pin  142  enters the final channel  162  as indicated by the arrows. When the pin  142  reaches its position as pin  142   e  in  FIG. 12 , the interference of the pin  142   e  with the shifter  129  to its right pushes the shifter  129  (and integral slidable section  131 ) to the right so that the pin  142  can move to its end position as pin  142   f.    
     The top of channel  162  is originally narrower than the diameter of the pin  142  (see  FIG. 11  for its earlier position). As the pin  142  enters channel  162  under water pressure force as indicated by arrow  170 , the pin  142  presses against the edge of saw tooth  152  and against shifter  129 , moving the shifter  129  and inducing slidable rotation of the slidable section  131  in relation to the upper and lower cam sections  128  and  130 , and a widening of channel  162  to allow the pin  142  to fully enter channel  162 . Arrow  172  in  FIG. 12  shows the direction of rotation of the slidable section  131  in relation to the remainder of the cam assembly  126 . As channel  162  widens through rotational movement of the shifter  129  coupled to the slidable section  131  of the cam assembly, the width of channel  158  is reduced (see  FIG. 12  as compared with  FIG. 11 ). When the pin  142  reaches channel  162  and completes widening it, the cleaning head assembly  124  ( FIG. 9 ) has reached a first limit position or a predetermined limit after completing a predetermined number of rotational steps and is no longer able to rotate further in the clockwise direction. 
     When the water pressure force is removed from the stem  140 , the pin  142  travels back down channel  162 . As the pin  142  does so, the angular position of the stem  140  begins to be incrementally and/or automatically adjusted in the counterclockwise direction just like it was previously in the clockwise direction. Under the influence of the intermittent water pressure force, and through the action of the engagement of the pin  142  within the cam assembly  126 , the angular position of the stem  140  continues to incrementally travel in the counterclockwise direction until the pin  142  slidably rotates the slidable section  131  back by entering and widening channel  158 , or through reaching a second limit position or predetermined limit. Through automatic positioning and reversal of the pin movement within the predetermined limits of the cam assembly, the cleaning head assembly automatically begins another cycle of movement in the clockwise direction after completion of a predetermined number of rotational steps. The ability of the slidable section  131  to slidably rotate with respect to the lower and upper sections  130 ,  128  enables the automatic reversal of the direction of rotation of particular implementations of cleaning head assemblies  124 . 
     While the implementation of a cam assembly  126  illustrated in  FIGS. 11 and 12  comprise only a few saw teeth  152 ,  154 ,  156 , and three channels  158 ,  160  and  162 , in other particular implementations, any number of saw teeth and corresponding channels may be employed. Such implementations may, therefore, incorporate smaller or larger rotational increments (steps), be evenly spaced or unevenly spaced, and/or incorporate a wider or shorter range of rotational movement before automatically reversing direction. For example, the saw teeth  152 ,  154 ,  156  may be spaced any distance apart to increase or decrease the stepwise rotational distance the stem  140  turns as water pressure force is intermittently applied. In addition, the degree of rotation of the stem  140  allowed by the number of saw teeth  152 ,  154 ,  156  employed may range in particular implementations from substantially 360 degrees to substantially 0 degrees, depending upon the desired location and function of the cleaning head assembly  124 . The rotation range to which particular implementations may be designed is limited only by the space needed for the left and right edges of the shifter  129  and the stops provided on the left and right of the upper and/or lower cam sections  128 ,  130 . It will be understood, however, that the actual dimensions of the stops and edges may vary greatly by the particular materials used to create the cam assembly  216  and the pressures to which the cam assembly is exposed. It is anticipated, however, that in most cases the rotation range needed will be sufficiently below 360 degrees and sufficiently above 0 degrees that the stops and shifter edges widths will not be a concern. 
     Also, in particular implementations, the relative sizes of the saw teeth  152 ,  154 ,  156  and/or angles of the channels  158 ,  160 ,  162  may be varied to allow the stem  140  to rotate a greater angular distance during certain rotational cycles than in others. Implementations employing regularly sized and spaced saw teeth  152 ,  154 ,  156  may employ a method of cleaning a pool floor that includes rotating the position of the stem  140  a certain predetermined distance within a predetermined or irregular interval of time. In implementations employing irregularly sized and/or spaced saw teeth  152 ,  154 ,  156 , the method may employ rotating the position of the stem  140  according to a predefined pattern during a predetermined or irregular interval of time. 
     Referring to  FIG. 13 , a flowchart of method steps is illustrated. Implementations of a pool cleaning head may include a method of use that may include the steps of intermittently raising the nozzle head (stem, step  174 ), incrementally rotating the nozzle head clockwise (step  176 ), and retracting the nozzle head (step  178 ). In particular implementations, steps  174 ,  176 , and  178  may be repeated multiple times, or may occur only once. Also, during the step of retracting the nozzle head (step  178 ), the nozzle head may also be incrementally rotated clockwise (step  176 ). As illustrated, method may also include the step of sliding a cam reverser (slidable section, step  180 ) and reversing the direction of rotation of the nozzle head with the cam reverser to counterclockwise (step  182 ). In particular implementations, these two steps may occur after a predetermined number of repetitions (cycles, or steps) of steps  174 ,  176  and  178 , or may occur after just one occurrence of each of steps  174 ,  176 , and  178 . In implementations of a pool cleaning head, the sliding of the cam reverser (step  180 ) and the reversing of the direction of rotation of the nozzle head (step  182 ) may be repeated automatically (along with the repetitions of steps  174 ,  176 , and  178 ) a predetermined number of times or according to a predefined pattern, allowing the pool cleaning head to incrementally and intermittently rotate through a particular arc of rotation or a fully 360 degrees for a desired period of time. 
     Implementations of cleaning head assemblies  216  employing removable and replaceable cam assemblies  222  may also enable adjustment of the overall orientation of the direction of total rotation (whether the rotation of the stem  140  is directed toward or away from a wall, for example) through exchanging of cam assemblies  222 . In a conventional cleaning head assembly, the pattern of intermittent spray is fixed and the cam teeth of the cleaning head are built into the cleaning head assembly. Replacement of the cam teeth for a different cam configuration or to replace a broken cam tooth requires replacement of the entire cleaning head assembly. An exchange or a replacement of a cam assembly  222  in particular implementations disclosed herein may be facilitated by decoupling the cap ring  136 , removing the locking ring  134 , removal of the cam assembly  126  and then replacement of the cam assembly  126  with another cam assembly that is either the same as the first (if repairing), or has different characteristics than the first (such as a degree of total rotation different from the first cam assembly). The locking ring  134  may be reapplied, the cleaning head oriented and its extents tested, and the cap ring  136  reapplied. 
     This ability to change the overall orientation of the direction of total rotation of the cleaning head assembly  124  also allows for directional adjustment after the cleaning head assembly  124  is installed in a pool floor, step, or sidewall to ensure more optimal routing of contaminants regardless of the initial installation of the cleaning head assembly  124 . The foregoing may allow an installer to tune the cleaning area covered by particular implementations of a cleaning head assembly  124  and perform adjustments without requiring specialized tools or lengthy disassembly or replacement. 
     In addition, implementations of cleaning head assemblies  124  may utilize a method of adjusting the orientation of the cleaning head assembly  124  after the cleaning head assembly  124  has been installed. Referring to  FIG. 14 , an implementation of the method is illustrated. The method includes the steps of disengaging a locking arm  204  engaged with a cap ring  136  (step  250 ), rotating the cap ring  136  in a first direction (step  252 ), adjusting a cam assembly  126  (step  254 ), rotating the cap ring  136  in a second direction (step  256 ), and engaging the locking arm  204  with the cap ring  126  (step  258 ). The method may further include pressing on the locking arm  204  through an opening  206  in the cap ring  136 . Rotating the cap ring  136  in a first direction (step  252 ) may further include disengaging a plurality of ridges  208  on a housing  132  with a plurality of grooves  210  on a lower section  130  of a cam assembly  126  and rotating the cap ring  136  in a second direction (step  256 ) may further include engaging the plurality of ridges  208  on the housing  132  with a plurality of grooves  210  on a lower section  130  of a cam assembly  126 . Rotating the cap ring  136  in a first direction (step  252 ) may also include disengaging projections  214  of the cap ring  136  from ramp members  212  of a locking ring  134 . Rotating the cap ring  136  in a second direction (step  256 ) may also include engaging projections  214  of the cap ring  136  with ramp members  212  of the locking ring  134 . The first direction may be either clockwise or counterclockwise and the second direction will always be in a direction opposite the first direction. Adjusting the cam assembly  126  may include rotatably adjusting the position of the cam assembly  126  so that the path of travel of the stem  140  during automatic cleaning operation covers a desired area of the pool. 
     Any of the above described heads or cam assemblies may be placed in various locations and in any combination throughout a pool to facilitate cleaning. Swimming pool cleaning heads, as described above or as otherwise known in the art, may be utilized and/or adapted to be utilized with the various implementations disclosed herein in accordance with the principles discussed and taught. Two examples of conventional swimming pool cleaning head designs particularly useful in swimming pool floors are illustrated in  FIGS. 16 and 17 .  FIG. 16  represents the water flow pattern of a swimming pool cleaning head having a continuously rotating water stream. An example of one particular implementation of this type of cleaning head is shown and described in U.S. Pat. No. 3,675,252 to Ghiz, issued Jul. 11, 1972, the relevant disclosure of the general operation, structure, manufacture and function of a continuously rotating cleaning head is hereby incorporated herein by reference. When water is supplied to the cleaning head, the head rotates slowly for a time period until the water supply is shut off. As shown in  FIG. 16 , a cleaning head  302  of a continuously rotating water stream is shown with an effective water stream  304 . Note that the effective water streams  304  and  306  are shown curved for the continuously rotating cleaning heads at each of times T(1) and T(N) due to the spiraling effect of the cleaning head  302  rotating in the direction  308  while spraying the water streams  304  and  306 . Throughout its 360 degree rotation for total time T(T), the conventional cleaning head  302  affects an effective area  310  of the cleaning head  302 . The effective area  310  of a cleaning head  302  is affected by the water pressure provided to the cleaning head  302  and the angle and size of the cleaning head nozzle. Those of ordinary skill in the art will readily be able to adapt an appropriate cleaning head effective area to a given implementation and cleaning head layout for a particular pool. One example of a continuously rotating swimming pool cleaning head is shown in U.S. Pat. No. 3,449,772 to Werner (issued Jun. 17, 1969). Continuously rotating swimming pool cleaning heads are not used in modern pool cleaning system designs for many reasons, some of which are described in U.S. Pat. No. 3,506,489 to Baker (issued Apr. 14, 1970). Instead, incrementally rotating swimming pool cleaning heads are preferred. 
     Incrementally rotating in-floor swimming pool cleaning heads are conventionally associated with a circuit having one to six cleaning heads. When water pressure is applied to the circuit, each of the heads in the circuit extends and begins to spray water in whatever direction the cleaning head jet nozzle happens to be pointing when the head extends. The cleaning heads each spray the water in its respective direction until the water pressure is released and then retracts back into the pool floor until the next cycle when water pressure is applied to the circuit. At the next cycle, each cleaning head is incrementally rotated from its previous position, thus spraying water in a different direction than before. This process continues each time water pressure is applied to the cleaning heads. For conventional systems where the in-floor cleaning heads rotate 360 degrees through a number of cycles, there is a high likelihood that a first cleaning head and a second head, whether on the same circuit or different circuit within the pool, will not spray in the same direction during a particular cycle. In fact, in many cases, the first and second heads may be pointed in exactly opposite directions essentially cancelling the benefit of each other in the pool cleaning system. If, for example, the first cleaning head in a first circuit was spraying debris toward the drain for a time and then a second cleaning head extended and sprayed debris away from the drain for a time, the benefit of the work the first cleaning head did would be considerably diminished. When the cleaning heads cycle through 360 degrees with equal jet force in all directions so that the net jet force for the cleaning head is zero, the cleaning heads essentially just stir up the debris with the hope that some of it will find its way to the drain. 
       FIG. 17  represents the flow pattern of a swimming pool cleaning head having an incrementally rotating water stream. An example of one particular implementation of this type of cleaning head is shown and described in U.S. Pat. Nos. 5,135,579 to Goettl (issued Aug. 4, 1992) and 6,848,124 to Goettl (issued Feb. 1, 2005), the relevant disclosures of the general operation, structure, manufacture and function of an incrementally rotating cleaning head is hereby incorporated herein by reference. Incrementally rotating cleaning heads are conventionally configured to incrementally rotate in response to the start and stop of water pressure controlled by a sequence valve. For each incremental location, the flow path is stationary. 
     As shown in  FIG. 17 , a cleaning head  312  of an incrementally rotating water stream is shown with an effective water stream  314 . Note that the effective water streams  314  and  316 , distinct from that of a continuously rotating water stream, are shown straight for the incrementally rotating cleaning heads at each of times T(1) and T(N) due to the fixed flow path for each flow location of the cleaning head  312  as it incrementally rotates in the direction  318 . Throughout its 360 degree rotation for total time T(T), the conventional cleaning head  312  affects an effective area  320  of the cleaning head  312 . The effective area  320  of a cleaning head  312  is affected by the water pressure provided to the cleaning head  312  and the angle and size of the cleaning head nozzle. Those of ordinary skill in the art will readily be able to adapt an appropriate cleaning head effective area to a given implementation and cleaning head layout for a particular pool. Typically, however, for a given water pressure and nozzle size, an incrementally rotating cleaning head will have a larger effective area than that of a continuously rotating cleaning head with the same pressure and nozzle size. 
       FIG. 18  is an example of a cross section of a conventional swimming pool. In this design, the swimming pool  322  includes pop-up cleaning heads  324  and a drain  323  in the floor  326  of the pool  322  and a skimmer opening  327  on a wall  328  of the pool. As used herein, a “wall” of a pool is any surface that is substantially vertical, and a “floor” of a pool is everything else. The floor  326  surfaces are the surfaces on which dirt and debris settle. In  FIG. 18 , the division between the wall  328  and the floor  326  is approximately indicated by line  330 , the floor  326  being the surface below the line  330  and the wall  328  being the surface above the line  330 . In conventional pool design, this line is commonly known as the “spring line.” 
     The example of  FIG. 18  also includes a swimming pool pump  332  and filter  334 , and a sequencing valve  336  coupled to individual cleaning circuits  1 - 6 . The circuits  1 - 6  which feed individual cleaning heads in the swimming pool in the pool floor  326 . Conventional systems have a typical flow of 55-60 gallons per minute. Some pool cleaning hydraulic systems use a single pump coupled to the filter to operate the cleaning heads through the sequencing valve like that shown in  FIG. 18 , other systems use separate pumps for the filter and cleaning heads. Sequencing valves are used for systems having incrementally rotating cleaning heads. 
       FIG. 19  illustrates three examples of differently sized conventional play pools where the center line  340  of the pool is the deepest part of the pool and is the line along which the drain  342  is placed. In a conventional pool, a plurality of 360 degree rotating cleaning heads  344  are placed in the floor of the pool to stir up the dirt and debris into entrainment in the pool water. After a time, the dirt and debris will settle again to the pool floor. The hope of pool cleaning system designers using this approach is that the dirt and other debris will be stirred up into suspension in the pool water and eventually be moved to the drain or the skimmer. It is commonly known in the pool industry that for large pools, in-floor cleaning systems cannot completely clean the pool. Rather, in-floor cleaning head systems used in large pools serve to gather debris in a plurality of localized areas so that a maintenance person can vacuum the debris by hand. If the debris in the pool is not the type of debris that settles to the ground (like dirt and leaves) but can remain entrained in the water, then the entrained debris can be filtered with the water through the skimmer and drain. However, if the debris is of the type that settles to the pool floor, conventional in-floor pool cleaning heads push the debris around to different locations around the pool floor as the incrementally rotating cleaning heads jet in their uncoordinated jet directions throughout their cleaning cycles. Once the debris either finds a “dead space” where a cleaning head cannot move the debris or the cleaning system stops, the localized debris areas may be hand-cleaned by a worker with a pool vacuum cleaner. 
     In occasional swimming pool designs, cleaning heads are placed in the wall of a swimming pool near the surface of the water to jet down the side of the pool wall, but wall-placed cleaning heads are less effective at cleaning the floor of the pool, are suitable only for small pools without steps or benches unless floor cleaning heads are also used, and are better suited for other purposes. One example of a swimming pool design using wall-placed cleaning heads is shown in U.S. Pat. No. 4,114,206 to Franc (issued Sep. 19, 1978).  FIG. 20  illustrates pool cleaning head placement for a conventional diving pool design with the drain near the deepest part of the swimming pool.  FIG. 21  illustrates pool cleaning head placement for a conventional lap pool design with the drain near the center of the pool, the pool having a fairly even depth throughout its length. The conventional lap pool example of  FIG. 21  also includes fixed, non-rotating wall-mounted cleaning heads  346  near the drain  345  configured to create a water curtain across the pool near the drain to catch debris moved across the plane of the water curtain and direct it toward the drain. Additional fixed direction, pop-up, non-rotating floor-mounted cleaning heads  347  may be included and directed toward the drain to further enhance the water curtain across the pool. U.S. Pat. No. 5,135,579 to Goettl (issued Aug. 4, 1992), the disclosure of which is hereby incorporated herein by reference, discloses a fixed directional cleaning head to capture debris stirred up by turbulence. An example of a swimming pool design, although it is for a diving pool design, using wall-placed and floor-placed cleaning heads is shown in U.S. Pat. No. 3,506,489 to Baker (issued Apr. 14, 1970). Baker includes floor-mounted cleaning heads with 360 degree rotation and wall-mounted cleaning heads mounted near the surface of the pool with partially rotating heads so that the water does not spray out of the pool. 
       FIG. 22  illustrates placement of a conventional floor cleaning head in relation to a corner of a pool near an inside corner to describe operation of the cleaning head in relation to dirt and debris movement. The cleaning head of  FIG. 22  is a sequentially rotating head having a jet direction radially from the cleaning head in each sequential direction. The arrows illustrate water flow movement near the edge of the effective area of the cleaning head. Debris and dirt  348  typically becomes trapped in inside corners of a pool. Distances A and B are the respective distances the floor-mounted cleaning head is placed from the first wall  349  and second wall  350  of the swimming pool. If a cleaning head is spaced equally from adjacent pool walls  349  and  350 , the dirt tends to build up on the corner and is not effectively removed. Instead, however, if A and B are different distances, the cleaning head more effectively removes the dirt and debris  348  from the corner through water flow being greater in one direction than in another as the cleaning head cycles through its sequential positions. As further illustrated by  FIG. 22 , water flow directed toward a wall travels along the wall, thereby carrying the debris along the wall. The substantially vertical walls of a pool can affect water flow in a beneficial way if used in coordination with a water flow plan for the pool using floor-mounted cleaning heads. For small pools, 360 degree rotating cleaning heads may be effective because of the effect the side walls have on the water and debris flow. In larger pools, however, 360 degree rotating heads are well known to create piles of debris that must be hand vacuumed by a maintenance person. 
       FIG. 23  illustrates a plurality of different possible jet configurations for in-floor mounted cleaning heads. Example A of  FIG. 23  illustrates a conventional cleaning head configuration where the effective area  352  of the cleaning head  350  is equal around all 360 degrees and through all of its cycles. The cleaning head  350  of this example sprays with equal force and volume in each of its evenly spaced directions  354  so that the net flow direction of the water emanating from the cleaning head  350  within one cycle at each jet position is zero. The net flow vector of a cleaning head is the sum of the water flow vectors for the cleaning head for each jet direction and cycle of the cleaning head. 
     Example B of  FIG. 23  illustrates an in-floor mounted cleaning head configuration where the effective area  356  exists in only about 180 degrees of the cleaning head  358  rotation. As a result, the net water flow  357  of the cleaning head  358  is clearly to the right of this cleaning head  358 . The effective area of a cleaning head in this and other examples provided herein may be altered in any of many different ways designed to create a net water flow in a particular direction. Some non-limiting examples of how the net water flow of a particular cleaning head may be altered include, but are not limited to: 1) altering the rotation of the cleaning head to only rotate between two angular extents (such as within a 180 degree range) and either cycle back to the beginning of the rotation or flip back to the beginning; 2) allowing the cleaning head to continue its 360 rotation but disallowing water jet from the cleaning head during a portion of its rotation; 3) allowing the cleaning head to continue its 360 rotation but spending less time in particular cycles or restricting a portion of the flow during particular cycles; 4) allowing the cleaning head to continue its 360 rotation but making greater jumps in its cycle during a portion of its rotation; 5) having decreased water flow volume or pressure during a portion of the cleaning head rotation to reduce the effective water stream strength at that part of the cycle; 6) combinations of any of these or other ways of creating a net water flow in a particular desired direction; 7) deflecting the jet away from the floor in a particular section of the cleaning head rotation; and 8) using a smaller hole on one side of the head and a larger hole on another side of the head to create differential net water flow on different sides of the cleaning head. 
     Examples C, D and E of  FIG. 23  illustrate some non-limiting examples of how differing in-floor mounted cleaning head jet configurations may allow for an in-floor mounted cleaning head with a net water flow in a particular direction. Example C illustrates a cleaning head  360  with jet directions  361  having effective jet area throughout approximately 270 degrees of the cleaning head rotation resulting in an effective area  362  for the cleaning head  360  only throughout those 270 degrees and a net water flow direction  363  for the cleaning head  360  to the right. Example D of  FIG. 23  illustrates an equal number of cleaning cycle directions  365  and  367  on all sides of the cleaning head  366 , but the cleaning cycles  365  on the left side of the cleaning head  366  have a smaller effective spray area than the cleaning cycles  367  on the right of the cleaning head  366 . This results in a net water flow direction  368  for the cleaning head  366  to the right. Example E of  FIG. 23  illustrates a fewer number of cleaning cycle directions  372  on the left side of the cleaning head  370  than on the right side resulting in a net water flow direction  374  for the cleaning head  370  to the right. These and many other examples are possible using any combination of techniques for creating a net water flow direction in a particular direction. Many other examples and how to implement the examples for use with in-floor cleaning head designs will become apparent from this disclosure. Two particular, non-limiting examples of pool cleaning heads capable of creating a net water flow direction are shown and described in U.S. Pat. Nos. 6,848,124 (for flush pop-up) to Goettl and 6,899,285 (for above surface) to Goettl et al. 
       FIG. 24  illustrates a symbol  376  for a pool cleaning head used to emphasize that the net flow vector for the cleaning head  377  is not neutral but is generally in the direction toward which the effective area  378  of the cleaning head  377  is facing. This symbol, or variations of it, is used throughout  FIGS. 25-31  to indicate that an in-floor cleaning head is used that has a non-neutral net water flow generally in the direction of the effective area markings for the particular cleaning head illustrated. 
       FIG. 25  illustrates an example of a basic implementation of a pool cleaning system using an in-floor cleaning head with a non-neutral net water flow direction. The example of  FIG. 25 , which may, for example, be implemented as a diving pool  381 , includes a debris collection point  380 , such as a drain, a debris capture zone  382  around the debris collection point  380 , and a plurality of pool cleaning heads on the floor of the pool  381 , the cleaning heads comprising at least one origin head  384  and at least one transition head  386  between the origin head  384  and the debris capture zone  382 . The origin head  384  or the transition head  386  shown in  FIG. 25  may comprise a recessed incrementally rotating nozzle assembly  10  or cleaning head assembly  124 . The recessed incrementally rotating nozzle assembly  10  or cleaning head assembly  124  may be configured to establish various net vector flows during the incremental use. The recessed incrementally rotating nozzle assembly  10  or cleaning head assembly  124  may be further used in any combination or location described in  FIGS. 24-34 . The pool cleaning systems described with regard to  FIGS. 23-34  are not limited to the specific incremental partially rotating cleaning heads shown and described with reference to  FIGS. 1-15 , but any of these particular implementations may be used in the pool cleaning systems therein described. This particular implementation also includes a second origin head  388  on the opposite side of the debris capture zone  382  from the first origin head  384 . 
     In operation, the pool cleaning system of  FIG. 25  may be coupled to a hydraulic system such as that shown in  FIG. 18  to have one or more pumps, a filter and sequencing valves to operate the cleaning head circuits for the pool  381 . Distinct from conventional in-floor cleaning head systems, the transition head  386  has a net flow vector toward the debris capture zone  382 . It has been found that establishing a jet from a sequencing nozzle for approximately 1 minute or more establishes a flow path in the direction of the jet within the pool water. In particular implementations of this and other implementations provided herein, the transition head may be configured so that it does not have any flow in a direction away from the debris capture zone. For this example shown in  FIG. 25 , this means that the effective area for transition head  386  would be less than or equal to 180 degrees so that it does not spray back toward origin head  384 . 
     In particular implementations of a pool cleaning system, such as is illustrated in  FIG. 25 , an opposing head  388  may be included on the other side of the debris capture zone. By having an origin head  384  at a first end of the pool in the example of  FIG. 25 , the effective area for the cleaning head is throughout 360 degrees and will clean out the corners of the first end of the pool to stir up the dirt and debris in that area. Cleaning heads with an effective cleaning area throughout 360 degrees of its rotation can be effective near the vertical walls of the pool. Because the origin head  384  is near the walls, as illustrated in  FIG. 22 , the dirt and debris is sprayed out of the corner and along the walls of the pool toward the transition head  386 . Because the transition head  386  of this example has a net flow vector toward the debris capture zone  382 , and particularly for this example does not emanate any water flow back toward the origin head  384 , dirt and debris is only pushed toward the capture zone  382 . The opposing head  388  similarly stirs up the dirt and debris from the second end of the pool and cleans out the corners of the second end of the pool which will push the dirt and debris toward the capture zone  382 . 
     The capture zone  382  for this non-limiting example comprises a drain  380 , a pair of fixed, non-rotating wall-mounted jets  383 , and a pair of fixed direction, pop-up, non-rotating floor-mounted jets  385 . The arrows associated with the wall-mounted jets  383  and the floor-mounted jets  385  indicate the spray direction for the jets; toward the drain  380 . By having an opposing head  388  on the side of the debris capture zone  382  opposite the transition head  386 , debris that flows beyond the debris capture zone  382  can be pushed back to the debris capture zone  382 . This helps to keep debris within the boundary between transition head  386  and opposing head  388  to be captured in the debris capture zone  382 . The water curtain generated within the capture zone by the wall-mounted jets  383  and the floor-mounted jets  385  may be cycled on and off like the other floor-mounted jets or may be turned off for portions of a cleaning cycle, but in almost all implementations will remain on throughout the cleaning cycles of the pool. 
       FIG. 26  illustrates three examples of how the principle of using transition cleaning heads may be applied to differently sized and configured pools where the capture zone  390  and  394  is near the center of the pool. Example A illustrates a play pool and example B illustrates a lap pool which is longer than the play pool and has two more transition cleaning heads. Each pool example comprises an origin head  396  at each end and at least one transition head  398  between the origin heads  396  and the capture zone  390 . As illustrated in these two examples, the principle of placing an in-floor origin head  396  near an end of the pool and an in-floor transition head  398  between the origin head  396  and the capture zone may be expanded for longer pools by simply adding more transition heads  398  between the origin heads  396  and the capture zone. By creating a net flow vector toward the capture zone  390 , and having cleaning heads with overlapping effective areas, the origin heads  396  can clean out the ends of the pool and the transition heads  398  can clean the middle portions of the pool and relay the dirt and debris toward the capture zone  390 . Example C applies the principle of transition heads  398  to a wider pool with the same effect. Example C is a wider pool with a longer capture zone  394  with two drains, and pairs of side wall-mounted jets  392  and floor-mounted jets  393  creating water flow toward the drains and a water curtain to capture debris. The principle of the water flow, however, works in this pool design similar to that of the smaller examples. Wall-mounted spray jets alone are incapable of cleaning wide or large pools because the water jet effective jet area is too small. Floor-mounted spray jets with a net zero flow vector alone are incapable of cleaning wide or large pools because they randomly spray water and stir up debris. The origin head  396  or the transition head  398  shown in  FIG. 25  may comprise a recessed incrementally rotating nozzle assembly  10  or one or more of cleaning head assemblies  124 ,  216 . The recessed incrementally rotating nozzle assembly  10  or one or more of cleaning head assemblies  124 ,  126  may be configured to establish various net vector flows during the incremental use. 
       FIG. 34  illustrates a directional vector flow of water in a swimming pool resulting from pool cleaning head placement and configuration according to a particular implementation of principles disclosed herein. The arrows in the illustration represent net water flow directions. The dashed lines surrounding each cleaning head  520 ,  522 ,  524  and  526  represent the effective area of the respective cleaning heads  520 ,  522 ,  524  and  526 . Note that by using origin heads  520  and  522  near the back walls of the pool, like with the example discussed in reference to  FIG. 22 , the resulting net water flow from the cleaning heads is along the back walls of the pool and then toward the center drain and water curtain within the debris capture zone  528 . The adjacent sets of transition heads  524  and  526 , which jet water toward the debris capture zone  528 , adjacent walls and adjacent transition heads but not back toward the origin heads, generate an additional combined net force toward the debris capture zone  528  when the jets from a transition head set  524  or  526  cross with each other. 
       FIG. 27  is a plan view of a very large pool implementation illustrating cleaning head placement and operation according to a particular implementation of a pool cleaning system. In this particular implementation of a swimming pool cleaning system comprises a swimming pool  400  having a skimmer  402  and a plurality of drains  404  coupled to a pump  406 . The pump  406  pumps water from the pool  400  to a filter  408  which is subsequently pumped through a sequencing valve  410  coupled to a plurality of water circuits through a circuit controller  412 . The circuit controller  412  may be a conventional mechanical or electrical system configured for regulating flow of water through the sequencing circuit. Furthermore, one or more of the water circuits may be configured to be continuously on, such as the circuit supplying the side jets  414  and floor jets  415  for the capture zone, by either bypassing the sequencing portion of the system or otherwise configuring the system for the desired flow. Each of the circuits may have one or more cleaning heads  414 ,  415 ,  416  and  418 . Given the principles discussed herein, those of ordinary skill in the art will readily be able to configure a conventional water circuit system for operation with an implementation of a swimming pool cleaning system disclosed. One problem commonly experienced in cleaning large pools using conventional methods is that not all of the cleaning heads on a particular row may be able to be on the same circuit. This means that the cleaning heads on part of a particular row may come on at a different time than the cleaning heads on another part of the row. This further complicates getting debris to the drains when net zero flow vector cleaning heads are used. 
     The example of  FIG. 27 , like that of  FIGS. 25 and 26 , includes both origin heads  416  and transition heads  418  between the origin heads and the capture zone defined about the drains  404  between the wall-mount side jets  414  and the floor-mount jets  415 . Although in this example each row of cleaning heads is shown as being coupled to a different water circuit, any of the cleaning heads may be coupled with any of the other cleaning heads in the same circuits or different circuits. It has been found that cycling through the circuits by starting with the region farthest from the capture zone first (i.e. the origin heads row) followed by sequentially cycling through rows closer to the capture zone to relay the debris and dirt toward the capture zone works best. The sequencing, by non-limiting example, could begin with the outer two origin head rows first, then move to the second outer row, then the second closest row, then the closest row last. Alternatively, by non-limiting example, the sequencing could alter beginning with the first pool end origin head row then the second pool end origin row, and then alter in toward the center in a similar fashion. Virtually any combination is possible and those of ordinary skill in the art will quickly determine the cycle order that works best for a particular swimming pool configuration from the examples and principles disclosed herein without undue experimentation. While some sequencing methods may provide better results than others, beneficial results from this system is not sequencing method dependent. 
     Contrary to conventional systems which rotate 360 degrees and merely stir up the debris with the hope that it will settle closer to the drain even when it is sprayed back toward the ends of the pool, the use of a transition heads increases the likelihood that the dirt and debris will settle closer to the drain because the transition heads have a greater tendency to not spray the dirt and debris back toward the origin head it came from. In essence, the use of transition heads helps to create a dirt and debris flow within the pool from a dirt and debris origin toward the capture zone rather than randomly stirring up the dirt and debris with the hope that it will settle in a better place. 
     A study was performed in which three pool cleaning systems were compared to determine the effectiveness of using transition heads for cleaning a swimming pool. All three pool cleaning systems used the same swimming pool with the heads located in the pool according to different cleaning head layout theories. All of the cleaning heads were incrementally cycling pop-up heads. For each test demonstration, approximately 400 synthetic leaves cut into 1½ inch triangles of vinyl sheeting were placed in the swimming pool prior to the cleaning system being turned on. The cleaning system was left on for one hour in each test demonstration and each test demonstration used the same pumping systems, but with a different cleaning head layout. Three separate test demonstrations were performed for each pool cleaning system. The first pool cleaning system used no water curtain and rows of adjacent cleaning heads in the pool; the second pool cleaning system used fewer but larger cleaning heads and a water curtain; and the third pool cleaning system used a water curtain and cleaning heads like the second pool cleaning system, but some of the cleaning heads were substituted to include transition heads and arranged as explained in relation to the principles discussed for the examples of  FIGS. 25 through 27 . 
     For the first pool cleaning system with no water curtain and two rows of cleaning heads, the three test demonstrations resulted in, respectively, 18, 19 and 48 leaves being collected with an average of 28 leaves per test. For the second pool cleaning system with a water curtain and incrementally rotating heads each rotating through 360 degrees, the three test demonstrations resulted in, respectively, 239, 138 and 143 leaves being collected with an average of 173 leaves per test. For the third pool cleaning system with the water curtain and incrementally rotating heads where some were transition heads, the three test demonstrations resulted in, respectively, 382, 356 and 326 leaves being collected with an average of 355 leaves per test. These tests indicate a significant increase (greater than 100%) in effectiveness through the use of transition heads over a conventional system having no in-floor transition heads. 
     Now referring to  FIG. 32 , a first method of designing and/or building a pool cleaning system with a predictable cleaning result is illustrated. Once a pool shape is designed, a pool cleaning system designer determines a location for one or more debris capture zones for the pool around debris capture points. In a pool configuration with a shape and one or more debris capture points, at least one debris origin point is identified and an origin head is located in the pool floor near the debris origin point (Step  500 ). Once the origin head is located, one or more transition head points are identified between each origin head and the debris capture point and at least one transition head is located between each origin head and the debris capture point (Step  502 ). The transition heads are each configured to generate a net water flow vector in the direction of the debris capture zone. Accordingly, the cleaning head system generally creates a flow vector toward the debris capture zone when in use (Step  504 ). This process, as demonstrated in this disclosure, is applicable to pools of any size and shape. 
     Now referring to  FIG. 33 , a second method of designing and/or building a pool cleaning system with a predictable cleaning result is illustrated. Once a pool shape is designed, a pool cleaning system designer determines a location for one or more debris capture zones (Step  506 ) for the pool around debris capture points. After the debris capture zone(s) is determined for the pool, the pool cleaning system designer determines a debris path (Step  508 ) for debris within the pool to the debris capture zone(s). Once the debris path is determined, the method of  FIG. 32  may be performed to generate a flow vector toward the debris capture zone. 
     As shown with specific regard to  FIGS. 30 and 31 , use of these principles enables a pool cleaning system designer to design a pool cleaning system capable of more effectively cleaning pools that it was not possible to effectively under prior art systems using conventional cleaning head arrangements. By applying additional water flow vector modules, each comprising at least one origin head and at least one transition head, to a swimming pool design, and expanding each water flow vector module to the necessary length by adding additional transition heads between the origin head and the debris capture zone, a swimming pool designer can pre-determine net water flow paths for the pool cleaning system and more effectively channel debris to the debris collection point within the pool. 
     Using conventional pool cleaning system design techniques, a pool was considered “cleaned” if the effective area of the cleaning heads in the pool were enough to cover the area so that all of the surfaces in the pool were sprayed. Using this type of design technique, however, there was no way to predict where the dirt would go. The result was that after the pool was designed and built, if the pool was not effectively cleaned and piles of dirt and debris was left on the pool floor, the contractor would need to come out and redo the cleaning system. Redoing a pool cleaning system can be a very expensive and time consuming process because many times parts of the pool must be demolished to replace the cleaning heads. In a particular method of designing and/or making a pool cleaning system, the pool cleaning system is configured so that the cleaning heads associated with a first circuit are farthest away from a debris capture zone, the cleaning heads associated with a second circuit are next closest to the debris capture zone, and the cleaning heads associated with a third circuit are closest to the debris capture zone. In this particular implementation, the circuits are supplied water and sequentially activated in the order farthest away from the debris capture zone to closest to the debris capture zone. In this way, debris farthest from the debris capture zone is stirred up toward the capture zone and is then transitioned to the next circuit&#39;s cleaning heads which are closer to the debris capture zone, etc. If the implementation uses transition heads in one or more intermediate circuits, the debris will more consistently be pushed toward the debris capture zone than if conventional 360 degree rotating, zero net flow value heads are used for all circuits. 
     The example illustrated in  FIG. 28  is an implementation of a principle of pool cleaning system design applied to a swimming pool of substantially uniform shape having outside corners. The swimming pool comprises a debris capture zone  420 , at least one origin head  422  in each leg of the swimming pool, at least one transition head  424  between each origin head and the debris capture zone  420 , and an opposing head  423  in an opposing side of the debris capture zone  420  from the origin heads  422 . The effective area of each cleaning head for this particular implementation is approximately 15 feet in diameter. For this particular implementation, the transition heads  424  have an effective area not greater than 180 degrees so that they do not generate any flow back toward the origin head  422  for the respective leg in which the transition head  424  is placed. This particular implementation also comprises two additional transition heads  426  configured with an effective flow area adjusted to generate flow into the leg of the pool having the debris capture zone and not toward any of the other legs of the pool. 
     The example illustrated in  FIG. 29  is an implementation of a principle of pool cleaning system design applied to a swimming pool having outside corners but a non-uniform pool shape and multiple capture zones. In this pool design there are three debris capture zones  428 ,  430  and  432 . Each of the debris capture zones  428 ,  430  and  432  for this implementation comprises at least one drain in the pool floor and fixed directional cleaning heads on opposing side walls and the floor adjacent the drain, the fixed directional cleaning heads spraying toward their respective drain. 
     The origin and transition pool cleaning heads are configured a little differently for each debris capture zone due to the shape of the pool. For this particular pool shape, it was determined that a debris origin point near a center of the largest open space for the pool was appropriate. Accordingly, an origin head  434  was placed there, one near the outside corner between the first and second capture zones  428  and  430  and one near the corners between the first and third capture zones  428  and  432 . Transition heads  436  were placed between these central origin heads  434  and each debris capture zone  428 ,  430  and  432 . Each of the transition heads is configured to generate a net water flow vector toward a particular debris capture zone. For the first debris capture zone  428 , a net flow vector module comprising an origin head  434  and a transition head  436  are placed between the end of the pool and the debris capture zone. In this way, the transition head  436  acts as an opposing head for the net flow vector module on the opposite side of the debris capture zone. There is no requirement implied for any implementation of a pool cleaning system that the opposing head be a cleaning head configured for 360 degree rotation. The effective area of each cleaning head for this particular implementation is approximately 14 feet in diameter. Various implementations will use cleaning heads suitable for the particular implementation. Effective areas for cleaning heads typically vary from a 2 to a 10 foot radius depending on the cleaning head and the associated pumping system. For the second debris capture zone  430 , two origin heads  434  were used as the opposing heads for the capture zone  430 . For the third debris capture zone  432 , like the first one 428, origin heads  434  and transition heads  436  were used. As is illustrated by this implementation, whether to use transition heads and how many transition heads are needed depends upon the specific pool shape and size and the effective area of each origin and transition head. Once the basic principles of implementing a pool cleaning system using net flow vector modules is understood, one of ordinary skill in the art will readily be able to design and implement a pool cleaning system for any pool shape using the basic principles. Two particular, non-limiting examples of pool cleaning heads capable of creating a net water flow direction are shown and described in U.S. Pat. Nos. 6,848,124 (for flush pop-up) to Goettl and 6,899,285 (for above surface) to Goettl et al. 
     The swimming pool implementation shown in  FIG. 30  is an implementation that cannot be effectively cleaned using conventional swimming pool cleaning system design principles. However, using net flow vector module principles, an effective pool cleaning implementation was designed. This particular implementation comprises a plurality of differently configured cleaning heads, each configured for its particular position in the pool. A first origin head  438  is included in the floor of the pool. This origin head  438 , although it is configured for 360 degree rotation, may be configured with a net flow vector toward the opening to the main body of the pool to better channel debris toward the debris collection points  439 . While this implementation illustrates only a drain within the debris capture zone, it should be understood that fixed directional cleaning heads (see  FIG. 27 ) may be implemented in the wall and floor of the pool adjacent the drains  439  to create wider debris capture zones. It should also be understood that for any of the implementations disclosed herein, a debris capture zone may comprise a plurality of transition cleaning heads having net flow vectors toward and surrounding the drain to enlarge the debris capture zone. This approach may be particularly useful for a drain that is not near a wall, such as in a large public pool. 
     At the edge of the main body of the pool in  FIG. 30 , a transition head  440  is configured for an effective area covering approximately 270 degrees with a net flow vector toward the two debris collection points  439 . Note that in this implementation, the transition head  440  is configured so that it does not spray water back toward the origin head  438 . The dashed lines indicate the boundaries of the effective areas of the transition heads in this implementation. Two origin heads  442  are included near the inside corners for the pool. Between the two origin heads  442 , two more narrowly configured transition heads  444  and  446  are configured to direct water flow toward the debris capture points  439 . Due to the space between the left side origin head  442  and the debris capture zones, an additional transition head  448  is included. One transition head  449  is included at the opening to each of the debris capture legs of the pool and the effective area for each transition head  449  is directed only within the openings to the debris capture legs of the pool so that debris is not blown out to the main body of the pool by these transition heads. The debris capture zones  439  may further be enhanced by adding side wall and floor fixed directional heads. Finally, two opposing heads  450  are included on the opposite side of the debris capture point from the transition cleaning heads  449 . 
     Using conventional in-floor cleaning heads with a zero net flow vector in this pool cannot effectively clean the pool due to the shape of the pool. Debris is repeatedly stirred up, the shape of the pool does not allow for effective settling near a debris collection point. Implementation of net flow vector modules in this pool enabled effective cleaning where it was previously not possible. In particular implementations of a transition head, the transition head is alignable during installation to allow for adjustment of the net water flow vector for the cleaning head. Two particular, non-limiting examples of alignable pool cleaning heads are shown and described in U.S. Pat. Nos. 6,848,124 (for flush pop-up) to Goettl and 6,899,285 (for above surface) to Goettl et al. 
     Like the implementation of  FIG. 30 , the swimming pool implementation of  FIG. 31  is one that cannot be effectively cleaned using conventional swimming pool cleaning system design principles. Using net flow vector design principles, however, each of the various features of this swimming pool may be effectively cleaned. Three debris capture points are selected for this pool at each of three remote locations. Each of the debris capture points comprises at least two fixed directional jet heads in a wall of the pool and at least two fixed directional jet heads in the floor of the pool directing water jets toward the debris capture point. These groupings each form respective debris capture zones  452 ,  454  and  456  for the pool. The positioning of the directional jet heads is determined based on the pool shape and debris capture point location. 
     Once the debris capture zones were identified, debris origin points are identified and origin heads  458 ,  460 ,  462 ,  464  and  466  are placed in the design near the debris origin points. For the island water feature  467 , a first origin head  458  is placed at a point around the island  467 . Note that a bench  480  surrounds a portion of the outer edge of the pool and a bench  482  surrounds the island feature  467 , thus making wall surface mount cleaning heads such as those disclosed in U.S. Pat. No. 4,114,206 to Franc (issued Sep. 19, 1978) unusable for these locations. Transition heads  468  are placed around the island, each having a net water flow vector away from the previous transition head to create a net water flow vector for the group away from the origin head  458  and toward the debris capture zone  452 . Thus, although a particular transition head  468  may not have a net flow vector directly pointing to the debris capture zone, it should be considered as having a net flow vector in the direction of the debris capture zone due to the shape of the pool, the influence of the vertical pool walls on the water flow, and the surrounding transition heads because the transition head  468  assists in generating a net water flow vector toward the debris capture zone. A transition head  470  is included at the opening of the island feature  467  to further reinforce the net water flow vector created by the transition heads  468  toward the debris capture zone  452 . 
     Central to the overall pool configuration, an origin head  460  is placed. It is determined that flow from the origin head  460  will go directly to debris capture zone  452 , and to transition head  472  to debris capture zones  454  and  456  and to transition heads  474  and  476  to debris capture zone  456 . Transition heads  472 ,  474  and  476  are placed accordingly in the design. In remote locations of the pool opposite the debris capture zones  452  and  454 , origin heads  462  and  464  are included and also serve as opposing heads to the respective debris capture zones  452  and  454 . Finally, origin heads  466  are placed for the beach entry and transition heads  478  are included between the origin heads  466  and the debris capture zone  456 . 
     It will be understood that implementations are not limited to the specific components disclosed herein, as virtually any components consistent with the intended operation of a method and/or system implementation for a nozzle assembly may be utilized. Accordingly, for example, although particular nozzle assemblies may be disclosed, such components may comprise any shape, size, style, type, model, version, class, grade, measurement, concentration, material, weight, quantity, and/or the like consistent with the intended operation of a method and/or system implementation for a nozzle assembly may be used. 
     In places where the description above refers to particular implementations of nozzle assemblies, it should be readily apparent that a number of modifications may be made without departing from the spirit thereof and that these implementations may be applied to other nozzle assemblies. The accompanying claims are intended to cover such modifications as would fall within the true spirit and scope of the disclosure set forth in this document. The presently disclosed implementations are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than the foregoing description. All changes that come within the meaning of and range of equivalency of the claims are intended to be embraced therein.