US 3926667 A
Description (OCR text may contain errors)
United States Patent 1191 1111 3, Gibellina Dec. 16, 1975 POOL CLEANING APPARATUS 3,289,216 12/1966 Anthony et 111. 134/167 R x 329L145 12/1966 Arneson 134/167 R  Inventor. Michael C. Glbelllna, Scottsdale, 3295540 H1967 Ortega H 134/167 R Al'lZ. 3,512,540 5/1970 Hughes 134/167 R A ig Ai i k Industries, Inc. Carlstadt, 3,718,148 2/1973 61136111113 4/172.15 X
N]. Primary E.raminerRobert L. Bleutge Flled? J 1974 Attorney, Agent, or Firm-Curtis, Morris & Safford  Appl. No.: 431,023
 ABSTRACT  US Cl 134/167 4/1725. 4/172 17 A rotatable pool cleaning head is continuously biased 51 Int. Cl. 1308B 9/08 toward the edges a Swimming P001 by a first water  Field of Search 4/17215, 172.16, 172.17; jet System and Propelled along the edge by a Second 134/167 R 168 15 210/169 water jet system. Self compensatory means are provided to angularly reorient the biasing of the water jet  References Cited systems to accommodate changes in the curvature of UNITED STATES PATENTS the pool perimeter as the cleaning head travels therealon I 3,170,180 2/1965 Winston et a1 15/1.7 g 3,265,079 8/1966 Blumenfeld 15 1.7 x 18Cla'm51 7 Drawing Flgures m 32 0 16 19 27 19 1B .,--;1 m--I'/4----- US. Patent Dec. 16, 1975 Sheet 2 of3 3,926,667
US. Patent Dec. 16,1975 Sheet3of3 3,926,667
POOL CLEANING APPARATUS The present invention relates to pool cleaning devices, and, more particularly, to pool cleaning devices traveling along and continuously biased toward the edge of a pool.
The prior art is replete with various devices for agitating the water adjacent the bottom and sides of a pool to maintain foreign particulate matter in a continuous state of suspension. Some of these devices, such that shown in US. Pat. No. 3,291,145, incorporate awater driven timing mechanism for periodically emitting a water flow through selected nozzles. The variable water flow from the nozzles tends to cause the device to travel in a prescribed path about a pool. A plurality of other devices, represented by the following US. Pat. Nos. 3,032,044, 3,139,099, 3,170,180, 3,265,079 and 3,289,216, teach various pool cleaning devices suspended from and movable about an arm extending fromthe side of the pool. US. Pat. No. 3,580,51 l, illustrates atransportable manually operated device for directing a spray of water toward the sides of a pool. US. Pat. No. 3,718,148, describing a device invented by the present inventor, teaches a pool cleaning device for ejecting a spray of water from nozzles tangential to the cleaning head. The ejected water causes the cleaning head to rotate and simultaneously wash the walls of the pool. Other water nozzles bias the cleaning head toward the pool walls.
All of the above devices operate more or less successfully but each of them have certain drawbacks or disadvantages. One of the primary disadvantages of the prior art devices resides in the complexity and associated expense of the various components. As the market within which these devices are sold is highly competitive, it becomes mandatory to simplify each of the elements of any apparatus to the greatest extend possible and thereby reduce the component cost. Further, non-clogging, easily maintainable and preferably interchangeable components must be used to provide a high degree of reliability and low maintainance costs.
Further, pool cleaning devices must be capable of continuously agitating the water adjacent 100 percent of the submerged surface of the pool and they must be capable of adequately and effectively cleaning the exposed sides of the pool to prevent the formation of evaporation rings and deposition of surface oil and debris.
It istherefore a primary object of the present invention to provide a pool cleaning apparatus for scrubbing the submerged and unsubmerged sides of a pool.
Another object of the present invention is to provide a rotatable pool cleaning head biased into contact with the sides of a pool by a first set of water jets and impart a lateral motion to the cleaning head by a second set of water jets to cause the cleaning head to roll along the pool perimeter. I
A further object of the present invention is to provide a means for maintaining a submerged contact between a pool cleaning head and the wall of a pool.
A still further object of the present invention is to provide a water feed line for a pool cleaning apparatus, which line does not entangle as the pool cleaning apparatus circumnavigates the pool.
A yet further object of the present invention is to provide pool cleaning apparatus which may be configured 2 to rotate in either a clockwise or a counter clockwise direction.
A still further object of the present invention is to provide an inexpensive pool cleaning apparatus.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.
The present invention may be described with greater clarity and specificity with reference to the following drawings in which: 7
FIG. 1 illustrates the components of the present invention disposed within a swimming pool.
FIG. 2 depicts the swivel connection intermediate the pool cleaning apparatus and the water feed line.
FIG. 3 illustrates an exploded view of the pool cleaning head.
FIG. 4 illustrates a cross-sectional view of the pool cleaning head manifold taken along lines 4-4, as shown in FIG. 3.
FIG. 5 illustrates a modification of the apparatus interconnecting the pool cleaning apparatus and the water feed line.
FIG. 6 illustrates a modification of the power jet for driving the pool cleaning apparatus.
FIG. 7 illustrates a cross-sectional view of the power jet taken along lines 77, as shown in FIG. 6.
Referring to FIG. 1, there is shown a cross-sectional view of a swimming pool 1 filled with water, as indicated by water level 7, and including the pool cleaning apparatus of the present invention. The pool 1 includes a bottom 2 having an essentially horizontal section and a sloping section, the latter terminating in a plurality of steps 4. The side walls 3 are terminated by a combing 5 contiguous with the surrounding pool deck. A tiled surface 6 is disposed in proximity to the water level 7 and a water supply outlet 10 is located in one of the side walls 3 in general proximity to the intended water level.
A water feed line 9 is attached to water supply outlet 10 to convey a flow of water to "the various jets and outlets of the present invention. Water feed line 9 includes a sinkable water hose 11 extending from water supply outlet 10. The sinkable hose 11 may be bisected with a swivel coupler 12 inserted therebetween. The coupler serves to relieve any twisting strains imposed upon hoses 11. One end of a pair of floating hoses 13, interconnected by another swivel coupler 25, is attached to sinkable hose 11 by further swivel coupler 26. The other end of floating hoses 13 is connected to a float coupler 14. With the above described configuration of the water feed line 9, a downwardly extending loop will be maintained in the line in proximity to the water supply outlet 10. The downwardly extending loop will prevent the hose from entangling as the latter moves about the pool.
A float 15 extends upwardly from float coupler 14 and maintains the latter at a predetermined distance beneath the water level 7. A snake or pool cleaning hose '17 is suspended from float coupler 14 by means of an elbow 16. A stream of water is ejected from the extremity of hose 17 and causes the lower part of the hose to randomly traverse the surfaces of bottom 2 and side walls 3 to randomly direct a stream of water against the adjacent surfaces. The ejected water tends to agitate particulate matter which has settled on the bottom and side walls and retains the particulate matter in suspens1on.
A second float coupler 28 is connected to the first float coupler 14 by means of hoses 18 connected to one 3 another by a further swivel coupler 27. Floats 19 may be added to hoses 18 to prevent the hoses from sinking and thereby drawing the two float couplers toward one another. If hoses 18 are floation hoses, floats 19 are not needed.
The second float coupler 28 includes a float 48 to maintain the float coupler at a predetermined distance beneath water level 7. A further hose l7 depends from float coupler 28 through another elbow 16. The further hose 17' conveys a stream of water adjacent the surfaces of bottom 2 and side walls 3 to maintain the surrounding particulate matter in suspension.
Additional float couplers may be included without departing from the teachings of the present invention. The requirement for further float couplers is essentially predicated upon the hoses l7 and 17 being capable of reaching the whole surface of the bottom 2 and side walls 3 when the float couplers are in proximity to the side walls.
The second float coupler 28 is connected to cleaning head 29 by a control arm 20, a coupler 23, a T fitting 21, a control arm 24, an elbow 30 and a swivel 31. The leg of T fitting 21 extends upwardly and supports a power jet 22. The power jet is set at an angle of 45 with respect to control arm 20 and directed away from cleaning head 29. In this manner, the reaction force created by the water flowing out of power jet 22 will tend to cause the attached assembly to move in a direction opposite to that of the ejected water. Swivel 31 extends downwardly from cleaning head 29 off-center of the vertical axis of the cleaning head. Thereby, the reaction force acting upon-swivel 31 will tend to cause the cleaning head to rotate about the swivel. The angular displacement of the cleaning head is limited by elbow 30 contacting one of a pair of stops 32 extending downwardly from cleaning head 29 on either side of the elbow.
A leading jet 37 is connected to a manifold disposed interior to dome 33 of cleaning head 29 through a coupler 36 at a location generallydiametrically opposed to swivel 31. The' leading jet is generally oriented in the same direction as power jet 22 but selectively angularly non-aligned therewith. A part of the water flowing into the manifold through swivel 31 is discharged through leading jet 37. The reaction force created by the ejected water from the leading jet will tend to cause cleaning head 29 to rotate in a direction opposite to that induced by power jet 22.
A jet 35 extends radially from dome 33 and is interconnected to the manifold within the dome. Thereby, a part of the water within the manifold is ejected through water jet 35. Water jet 35 is positioned above water level 7 such that the water ejected therefrom will strike and wash the tiles 6 of side wall 3 extending above the water level 7.
A floation ring 34, having a radially extending annular band about its lower edge, is disposed about dome 33 and extends outwardly therefrom. The buoyancy of the floation ring is established such that the annular band and below the water level 7. Any contact between cleaning head 29 and side wall be by means of the annular band and below the water level. Thereby, the cleaning head will not scrape, rub or otherwise leave any marks upon the side wall 3 above the water level. Further, surface oils and debris will not be transfered to the exposed tiles 6.
Through experimentation it has been learned that the action of the cleaning head 29 creates a partial vacuum within dome 33, which vacuum causes the cleaning head to float lower than optimum. To relieve the vacuum, a plurality of holes 52 (see FIG. 3) are formed in the top surface of dome 33.
Where the steps 4 extend beyond the side wall 3 of the pool at a depth insufficient to clear the apparatus depending from cleaning head 29, a rotatable disc 38 may be used. Disc 38 is connected to cleaning head 29 by means of a pipe 40 extending from the manifold to a depth sufficient to clear the adjacent apparatus. The diameter of the disc is equal to or greater than that of the adjacent apparatus such that the disc and not the apparatus contacts the riser of the step. Thereby, the disc 38 prevents the cleaning head 29 from becoming jammed against the underwater depending apparatus.
The details of swivel 31 will be described with respect to FIG. 2. A hollow stud 4l is interconnected with and extends downwardly from the manifold within dome 33. A sleeve 44, having a radially extending lip 45 at its I lower extremity, is secured within stud 41 by a screw 47. Where dimensionally necessary, a spacer 46 may be inserted intermediate sleeve 44 and stud 41. A further sleeve 42, having a radially inwardly extending lip 43, interlocks with lip 45 of sleeve 44. Sleeve 42 is fixedly secured to the upwardly extending part of elbow 30. Elbow 30 may be threadedly connected to control ann 24 as shown, or it may be adhesively connected thereto.
The construction of cleaning head 29 will be described in detail with reference to FIG. 3. The floation ring 34 includes a sleeve 50 frictionally engaging the lower skirt of dome 33. An annular band 51 extends radially from sleeve 50 and defines the outermost extremity of cleaning head 29 whereby it and only it will contact the side wall when the rotating platform is in proximity thereto.
A downwardly oriented cap 53 is centrally mounted within dome 33. The cap includes an aperture 54 disposed in one wall thereof. The upper sleeve 61 of a dual swivel coupling mates with cap 53. An aperture 62 is disposed within sleeve 61 to mate with aperture 54. Jet 35 includes a tube 56 extending interior to dome 33 through an aperture 55. Tube 56 also extends through apertures 54 and 62 within cap 53 and sleeve 61, respectively. When tube 56 is inserted through the respective apertures, sleeve 61 will be secured within cap 53.
The lower sleeve 63 of dual swivel coupling 60 is mounted within a hollow stud 65 extending upwardly from manifold 59. A screw 67 interconnects stud 65 and sleeve 63 through apertures 66 and 64, respectively, to secure the manifold to the coupling.
As best illustrated in FIG. 4, the manifold 59 includes an aperture 70 directed lateral to control arm 24 (see FIG. 1) when the latter is angularly centered with respect to stops 32. The purpose of aperture 70 is that of agitating the surface. A further aperture 71 is disposed in the bottom surface of manifold 59. Aperture 71 directs a stream of water downwardly to agitate any particulate matter resting upon elements laterally protruding from side wall 3, such as steps 4 shown in FIG. 1.
The operation of the present invention will now be described. When a water valve (not shown) is opened, water will flow from water supply outlet 10 through water feed line 9. A part of the water flow will be ejected through power jet 22 to establish a reaction force upon control arm 24. The reaction force will tend to rotate cleaning head 29 about its vertical axis in a counter clockwise direction. Simultaneously however, water will flow into manifold 59 with a part of the water being ejected through leading jet 37.
If the cleaning head 29 is located withinthe pool but not adjacent one of the side walls 3, the reaction force created by both the power jet and the leading jet will tend to propel the cleaning head forwardly and laterally until it contacts a side wall. When the annular band 51 contacts the side wall, it will usually not be at an angle normal to the side wall. Hence, the reaction force from the power jet and the leading jet, will cause the rotating platform to travel along the side wall while maintaining contact therewith. The frictional force established be tween the annular band 51 and the side wall 3 will cause dome 33 to roll along the side wall without corresponding rotation of manifold 59. The jet 35, rotated by dome 33 sprays water in a circular pattern about the dome and washes the side walls 3 extending above the water level. As the annular band 51 is below the water level 7, it will not leave marks upon the exposed side wall, which marks would ultimately become baked by the sun and permanently disfigure the exposed side wall.
If pool 1 includes steps extending into the pool at a depth insufficient to clear the apparatus depending from the cleaning head, disc 38 is attached to guide the cleaning head around these obstructions.
Through experimentation, it has been found that excellent results are achieved if power jet 22 is oreinted at an angle of 45 with respect to control arm 24. The biasing of the cleaning head 29 against the periphery of pool 1 is essentially controlled by leading jet 37. The bias may be increased by angularly reorienting leading jet 37 from a position essentially parallel from'that of power jet 22 to a more outwardly directed angle.
The swiveling capability of control arm 24 with respect to the cleaning head 29 will present the unit from becoming stalled should it strike a side wall at an angle of 90 with respect to the reaction force created by the power and leading jets. In such a case, control arm 24 and manifold 59 will swivel with respect to dome 33 to allow the force exerted by the power and leading jets to be angularly reoriented from that of the initial position. The reorientation will quickly create a lateral force upon dome 33 and the latter will resume its travel along the periphery of the pool. The imbalance of reaction forces created by the power and leading jets is further enhanced is the angle therebetween is large.
Through experimentation, it has been learned that swivel 31 and stops 32 may be deleted by incorporating a flexible hose in place of control arm 24, such a modification is illustrated in FIG. 5. A sleeve 80 is adhesively secured to stud 41 and threadedly interconnects an elbow 81 to the stud. A flexible hose 82 is secured to elbow 81 and extends lateral to manifold 59. The flexible hose 82 terminates in a fitting 83.
Sleeve 80 includes a pair of diametrically opposed apertures 85 and 87 disposed within the threaded portion of the sleeve. A similar sized aperture 86 is disposed within the threaded portion of elbow 81 to selectively cooperate with one of apertures 85 or 87. By orienting aperture 86 with aperture 85, as shown, a jet of water will be ejected therefrom. The reaction force of this jet of water will essentially correspond to the reaction force established by the leading jet 37 disposed at the other end of manifold 59 (see FIG. 3) and be oriented in essentially the same direction. Thereby, the travel of the cleaning head 29 will be in a direction op- 6 posite that of the water ejected through aperture and leading jet 37. As the force exerted by the ejected water will be essentially equal, the manifold 59 will not tend to rotate with respect to flexible hose 82.
Previously, the swivel 31 interconnecting the power jet 22 and the manifold 59 permitted a lateral bias to be applied to the cleaning head 29 when it became stalled against a wall of the pool 1. With the modification as shown in FIG. 5, such stalling is prevented by the flexible nature of hose 82. The force exerted by the power jet 22, assuming the cleaning head to be positionally stalled, will tend to bend the flexible hose in one direction or the other because the reaction force established by power jet 22 is in non-alignment with the flexible hose. When the flexible hose 22 bends, the force exerted by the power jet will be translated to a lateral force acting :"upon the cleaning head, which lateral force will cause the cleaning head to begin traveling the pool perimeter.
The inclusion of a separate fitting and the necessary couplers to form power jet 22 can be circumvented by a modification to the second float coupler 28, as shown in FIG. 6. By connecting fitting 83 directly to the float coupler 28, the control arms 24, coupler 23, T-fitting 21 and power jet 22 may be deleted. To obtain the necessary reaction force of power jet 22, a pair of apertures 91 and 92, see FIG. 7, are disposed within the upper neck -of float coupler 28. These two apertures are oriented at an angle of approximately 45 with re spect to a horizontal center line passing through the float coupler.
In operation, one of apertures 91 and 92 is closed off by means such as a screw 93. A jet of water will thence flow through the remaining open aperture and establish a reaction force acting upon the float coupler 28. The selection of aperture 91 or 92 is dependent upon whether the rotating platform is to travel clockwise or counter clockwise about the perimeter of the pool.
With the arrangement of parts shown in FIG. 3, the cleaning head 29 will travel in a counter clockwise direction. In a clockwise direction is desired because of the configuration of the pool, or other requirements, one of the stops 32 is momentarily dislocated to permit rotation of elbow 30. The leading jet 37 must also be reversed and the power jet 22 must be realigned and directed awayfrom the other side of control arm 24. Similarly, if the rotation of the cleaning head 29, incorporating the modifications shown in FIGS. 5, 6 and 7, is to be altered, elbow 81 is rotated within sleeve 80 until aperture 87 mates with aperture 86; aperture 92 within neck 90 is openedby removing screw 93 and inserting the latter within aperture 91. Leading jet 37 must also be reversed.
From the above description, it will become apparent to those skilled in the art that the use of the modifications illustrated in FIGS. 5, 6 and 7, eliminate all moving parts from the present invention except that of the dual swivel coupling 60 intermediate dome 33 and manifold 59. Thus, the expense of the present invention has been reduced, maintainance requirements have been substantially decreased and the complexity has been minimized.
While the principles of the: invention has now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions,
the elements, materials, and components, used in the practice of the invention which are particularly 7 adapted for specific environments and operating requirements without departing from those principles.
1. A pool cleaning apparatus for washing the bottom and side walls of a pool, which pool includes a water supply outlet disposed in one of the side walls, said apparatus comprising in combination:
a. a cleaning head movable about the surface of water within the pool, said cleaning head including:
1. a water manifold for receiving and distributing a flow of water; and
2. a dome freely rotatably supported on said manifold, said dome having a vertical axis of rotation and being rotated on said axis with respect to the manifold by contact with the side wall as the cleaning head moves along the side wall;
b. hose means operatively connected to the water supply outlet for supplying a flow of water to said water manifold; said hose means including means forconnecting the hose to the manifold and for allowing relative movement between the hose and manifold at least in a horizontal direction;
0. power jet means extending from said hose means upstream of said connecting means for urging rotation of said cleaning head in a first direction about the vertical axis;
d. leading jet means extending from said manifold downstream of said connecting means for urging rotation of said cleaning head in a second direction about the vertical axis, said leading jet means, in combination with said power jet means, propelling said cleaning head forwardly and laterally; said leading and power jet means being normally positioned at a predetermined angular relation to each other, which angular relation may be varied during operation of the apparatus, should the cleaning head become stalled against the side wall, as the power jet causes said hose to move horizontally about said connecting means, thereby to change the angle of the effective repulsive force applied to the cleaning head by said leading and power jets and unstall the cleaning head;
e. a flotation ring disposed about said dome for supporting at least a part of said dome above the surface of the water, said flotation ring including an annular band extending radially outwardly from said dome below the surface of the water such that only said annular band contacts the side wall of the pool when said cleaning head is adjacent the side wall, said dome being rotated by the friction existing between said annular band and the side wall due to the forward and lateral movement of said cleaning head;
f. water jet means extending radially from said dome and rotating with said dome for directing a flow of water against the side wall above the water level of the pool to wash the unsubmerged part of the side wall; and
g. at least one snake extending from said hose means for randomly spraying a flow of water against the submerged side walls and bottom of the pool; whereby said power jet means and said leading jet means cooperate to prevent stalling of the cleaning head in a fixed position along the side wall and propel said cleaning head about the perimeter of the pool while said water jet means and said snake wash the unsubmerged side walls and the bottom of the pool.
2. The apparatus as set forth in claim 1 including at least one float coupler attached to said hose means for supporting said hose means in proximity to the water surface of the pool.
3. The apparatus as set forth in claim 2 wherein said hose means includes a plurality of serially connected lengths of hose and a swivel coupler disposed intermediate adjacent lengths of hose to prevent snarling of said hose means.
4. The apparatus as set forth in claim 3 wherein a first one of said lengths of hose connected to said water supply outlet is sinkable and a second one of said lengths of hose connected to said first length of hose is floatable; whereby, said first and second lengths of hose will define a downwardly directed loop from the water supply outlet to preclude said cleaning head from becoming entangled with said hose means.
5. The apparatus as set forth in claim 1 where said hose means includes rigid control arm means operatively connected to said connecting means and extending upstream therefrom for supporting said power jet means.
6. The apparatus as set forth in claim 5 wherein said connecting means comprises a swivel connection affording limited angular movement in the horizontal plane to said control arm means; whereby, the reaction force exerted by said power jet means is angularly redirected when said cleaning head encounters an obstruction otherwise tending to limit further movement of said cleaning head.
7. The apparatus as set forth in claim 6 wherein said power jet is directed at an angle of with respect to said control arm means.
8. The apparatus as set forth in claim 2 wherein said power jet means is disposed within said float coupler.
9. The apparatus as set forth in claim 1 including a rotatable disc centered upon the vertical axis of said cleaning head and disposed below said water manifold to engage the side wall of the pool when said annular band encounters an indentation in the adjacent section of the side wall.
10. The apparatus as set forth in claim 1 wherein said connecting means includes a flexible length of hose connected between said manifold and said power jet whereby said flexible length of hose will tend to angularly redirect the reaction force generated by said power jet means upon said cleaning head to urge said cleaning head around obstructions in its path.
11. The apparatus as set forth in claim 10 wherein said power jet means is directed at an angle of 135 with respect to said flexible hose.
12. A swimming pool cleaning apparatus for washing the bottom and side walls of a pool that includes a water supply outlet disposed in one of its side walls, said apparatus comprising, a buoyant cleaning head movable about the surface of water within the pool and including a water manifold for receiving and distributing a flow of water; hose means operatively connectable to the water supply outlet of the pool for supplying a flow of water under pressure to said water manifold, said hose means including means for connecting the hose in fluid communication to the manifold and means for allowing relative horizontal movement between the hose and manifold; first jet means on said hose, upstream of said means for allowing horizontal movement, for forming a first water jet from water flowing in said hose; second jet means operatively associated with said manifold for forming a second jet of water from water under pressure in said manifold, said first and second jets being normally located in a predetermined angular relation to each other to produce a combined reaction force propelling said cleaning head forwardly along and laterally against the sidewalls of the pool; said means for allowing horizontal movement allowing the angular relation of said jet means to be varied under the influence of said first jet means should forward movement of the cleaning head become stalled, thereby to change the angle at which the combined reaction force is applied to the cleaning head and unstall the head.
13. The apparatus as defined in claim 12 wherein said means for allowing horizontal movement comprises a swivel; means for limiting movement of said hose on said swivel; and wherein said hose includes a rigid control arm operatively connected between said swivel and said first jet means.
14. The apparatus as defined in claim 13 wherein said first jet means is mounted on and supported by said control arm.
15. The apparatus as defined in claim 12 wherein said means for allowing horizontal movement comprises a 10 flexible length of hose connected between said connecting means and said first jet means.
16. The apparatus as defined in claim 15 wherein said connecting means has an aperture formed therein opening in substantially the same direction as said sec- 0nd jet means, to form a third jet of water cooperating with said second jet means to propel said cleaning head.
17. The apparatus as defined in claim 12 wherein said cleaning head includes a dome rotatably mounted on said manifold and water jet means extending radially from said dome; and means for providing fluid communication between said manifold and said water jet means while allowing rotary movement of the water jet means thereby to produce a jet of water directed against the sidewall of the pool.
18. The apparatus as defined in claim 12 including at least one snake hose section connected in fluid communication to said hose and extending therefrom to a free end for producing a randomly moving spray flow of water against the submerted side walls and bottom of the pool.