Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2739939 A
Publication typeGrant
Publication dateMar 27, 1956
Filing dateMay 6, 1952
Priority dateMay 6, 1952
Publication numberUS 2739939 A, US 2739939A, US-A-2739939, US2739939 A, US2739939A
InventorsLeslie Donald J
Original AssigneeLeslie Donald J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Swimming pool water level control system
US 2739939 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

March 27, 1956 J, LESLIE 2,739,939

SWIMMING POOL WATER LEVEL CONTROL SYSTEM Filed May 6, 1952 2 Sheets-Sheet 1 F a e [9.1. i 2420i I4 22 25 III a I A INVEN TOR.

BY Z/W March 27, 1956 D. J. LESLIE SWIMMING POOL WATER LEVEL CONTROL SYSTEM Filed May 6, 1952 2 Sheets-Sheet 2 DOA/HAO d. 55

INVEN QTTOQA/EV United States Patent- SWIMMING POOL WATER LEVEL CONTROL SYSTEM Donald J. Leslie, Pasadena, Calif.

Application May 6, 1952, Serial No. 286,287 2 Claims. (Cl. 210-11) This invention relates to a water circulating system for swimming polls or the like, and in which the water of the pool is intended to be cleaned, as by passing it through a filtering tank.

One method of maintaining the water of a swimming pool clean is to skim the surface thereof continuously, since a major portion of foreign material collects at the surface. To this end, a skimming gutter is customarily provided, and a thin film of water is intended to flow over the ledge of the gutter from the main body of water, thence passed through a filtering tank, and back to the main body of water, with the assistance of a water pump.

For proper operation of the pump, the rate that the water flows into the skimming gutter must precisely balance the rate at which the pump can withdraw this water. If such condition can be maintained, the pump continuously has its charge, thereby avoiding an air lock. Furthermore, this balanced relationship is important in order that the level of Water in the gutter may be maintained sufliciently below the ledge for the skimming action to take place. This balanced condition is highly dependent upon a precise incremental height of water of the pool as compared with the level of the ledge of the skimming gutter. If the water level is too low, water enters the gutter at a reduced rate and the pump runs dry. If the water level is below the ledge, no cleaning action whatsoever takes place. If the level is too high, the gutter becomes filled since the capacity of the pump has not increased, and soon the level of the gutter is the same as that of the main body of Water, and no skimming action or surface flow takes place.

A float valve operated in response to a change in level of the water in the pool could be provided, adding water to the pool from an external source. In such a system, the operating mechanism would have to be set such that a very accurate level would be maintained with respect to the rate at which the pump withdraws the water over the ledge, in order to make best use of the pump. If the rate that the pump withdraws the overflow water be sub ject'to change, such valve mechanism would have to b adjusted accordingly. Furthermore, such adjustment would be extremely critical, since even a few thousandths of an inch added to the water level would have a cumu lative effect upon the system.

It is an object of this invention to overcome such disadvantages, and to improve, in general, the circulating systems of this general character.

It is another object of this invention to provide a circulating system for a swimming pool or other body of liquid, utilizing a skimming gutter in which the level of water in the pool is automatically maintained within extremely close limits in relation to the rate that the pump can handle the overflow. By such a system, independent adjustment of a flat operated mechanism for different pump installations is obviated, andthe system can readily be operated for different circulating rates.

It is another object of this invention to provide a system of this character that maintains a precise level of wa- 2,739,939 Patented Mar. 27, 1956 ter. the pool without requiring expensive extra-sensitive equipment.

\ It is still another object of this invention to provide an improved system for maintaining a precise level of water .in a swimming pool, or other container, utilizing'a sump fed by the skimming gutter, and an external Water supply operated in response to a decrease in-level of water in the sump, thereby maintaining a charge for the circulating pump, and providing anincremental volume of Water for the pool as determined by a decreased rate of flow of water into the skimming gutter. y

This .invention possesses many other advantages, and has other objects which :may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose-there is shown a form in the drawings accompanying and forming part of the present specification; The form will now be described in de- Figs, 4 and 5 aresectional views, taken along the planes indicated by lines,,44 and 5,: -5{Of Fig. 3, respectively;

Fig. 6 is a View similar tqFig, :3, illustrating a modified form of the present inventiomand I Fig. 7 .is a sectional view, taken alongthe plane indicated byline77ofFig.6. .,g

In the drawings, a conventional. form of swimming pool 10, formed in this instanceofpoured concrete, is illustrated; Itcontains, a main body of water 11. At one end of the swimming pool there is provided an outlet 12 of a water supplyline ,13 for maintaining the desired volume o f water llin the. pool 10. At the other endof the pool 10 is a scumgutter .14 adapted to receive water from the pool .10. It is generally of channel configuration. Oneside of the gutter 14 is formed by a vertical ledge 15, the upper edge of which cooperates with the uppersurface 16 of the body. of water 11 to produce a skimming action. The gutter 14 may be formed of poured concrete integrally with the pool, or in any suitable manner. l 1

The gutter 1'4 is'ill ustrated as extending only along one end of the pool 10, and thesupply line 13 is illustrated as disposed at the opposite end of the pool 10. Accordingly, the flow of the upper level of Water extends uniformly in one direction substantially throughout the length of the pool. A, complete skimming action is thus provided. Other arrangements could be provided; the specific form herein illustrated serves merely asa basic organization in which the system incorporating this invention is used.

If the surface 16 is slightly. above the ledge 15 and the level of water in the gutter is substantially less, a film of water will flow over the ledge, producing'the desired skimming action. v

This upper film of water may boot the order of several hundredthslof an inch in' thickness. It will contain a substantial amount of any foreign material that may be in the pool.' I

Water received by the gutter l4 is intended to be recirculated by the aid of conduit means 17, a pump 18, and a supply line 13leadingbackinto the main body of water 11. A usual filter tank 19 is interposed in the recirculationpath, A vselectively adjustable valve 30 controls the flow of water in the conduit 17 to the pump 18 An outlet conduit 31 between the deep end of the pool and. the conduit l'Lprovides .tonthecirculationoftwatem from the lower levels of the pool, at which place additional foreign material may exist. A valve 32, similar to valve 30; is :placed in':th'e co'nduitf'i'al and i's' adjustable? fIfWillf i first be assumed that the valve 32 is completelycloseds The level 16 must -be'm'aintained at a definite'value as compared with theledge and the capacity of the pump 18 in order to maintain propeF cleaning efficiency forthe pool 10.

If the level'16-exce'edsa certainamount for a given rate of withdrawal of the -overflowfwater by-the pump 18, the'level' of water 'in the gutter 14 must rise. The

skimmingaction of the'ledge- 15'may*be impaired'byvirtue of an equalization of levels onboth sidesof theledgel;

On the other hand;- should the" level 16 ofthe main body 'of wate'r be' less-thana certain amount for a given rate of withdrawal,- even to the'extent ofa few thousandthsof an inch, improperoperation of the pump will result. Thus, the-system will operate to injectairinto the pump, thereby producing an undesired" air lock. The Also, the flow" of water will be less than can be accommodated bythe' pump 18, and the' systetn' will not 'be operating at its skimming action will-then be irregular;


To overcome these conditionsga sump 21 forms a part of a continuous recirculation path-of the water; This sump 21 accommodates a relatively small body of water; It-may-be formed in anappropriatemanner' adjacent the gutter 14. The sump 21 maintains a-charge'fo'r the pump 18 and determines a proper level of thesurface 16; It is fed by an outlet conduit 22from the" gutter14,-and it feeds theconduit means --17- to the pump" 18. The pump 18 the sump 21- filled'with w'ater, thej'system' will be" oper'-" atingat its maximum circulating eiificiencyz' Since a certainf volume 'ofiwater must inevitably be" lost from the pool 10, throughevaporation "and'oth'er' causes, th'e level of the surface 16 of"thefpool 10 would ordinarily tend to lower with respect to the ledge 15. To overcomethis tendency, an -ex'ternalsupply line 20*di5 rectly supplies water-to'the sump 21' as needed 101118111 tain it at a certain-level 23','-bel'ow-the level'16 of lthe" poolj For this purpose, a 'fva lve 24 isdllirstrated "that is controlled by'a seams itfthe sump 21: Should'tlrei' level of the surface 16 lower suchgas to provideamin sufficient how of water into" thesum'p 21, withrespectto the rate'of "withdrawal therefrom, the float'25 Will-operate to introduce additional wate r. g H

By supplying w'atei" directly-1o the-shmp, 21' rather than to the main body'of-'\ vater1l,it continuously operates whh a ful'lfcharge ofjfltiid'. The

supply-20,--it will discharge waterinto the pool at -a rate" dependent only upon its set :operating condition. Thus, if the rate of withdrawal of water from the sump 21 by the pump 18 is suddenly increased, such .as by further opening the valve 30, the pool 10 momentarily receives more water than is discharged therefrom over the ledge 15. But such condition is soon overcome when the level of the surface16- rises under the influence of a greater rate of supply of water from'the supply outlet 12. At such time, the discharge over the ledge 15 increases by virtue of the increased incremental height of the surface 16. Such increased discharge .over'the ledgeliplus the water added to the sump 21. from. the'external supply 20, will bring the system into equilibrium for a greater rate of circulation.

Should the rate of withdrawal of water from the sump 21 he suddenly reduced, such as by manipulating the valve 30; the pool, 10' momentarily will dischargemore water over the ledgelS than it receives'from the supply outlet 12." The level 2301' the sump 21 will then rise above the cut-off position of the float 25. The levelylfti" above the ledge 15 wilfthen drop to a point in. which the discharge rate-into the gutter 14 is balanced by rate of supply from the pump 18. Evaporation soon re; duce's the water in the system, and the level in the: sump zf'th'en drops below the cut-off position of the float 25,.1

.andnormal steady state operation resumes for a reduced} rate off circulation. The level ofthe sump 21 may-11011 mallylbe sufiicientlybelow the top ofv the ledge 15. solas measure that even in'the eventof an extreme rise in. the... level of the sump 21, such as occasioned. by a sudden; lowering in the ratev of withdrawal .of water from. the. sump- 21 by. the pump-18,.the sump Water does not.rise.. sufiiciently to impair proper skimmingaction. 1

Byflutiliiing the sump construction, 21 with a float 25.. directly .Iesponsiveto an-increased capacity of the pump,

7 18, the system can. smoothly adjust itselffor operation according to the condition of the pump18 and the setting of the valve 30.

The present system makes it possibleto use a small size n pump: 18'," minimizing the cost of a circulating system, Y but yet. insuring .that the level of the surface 16 corre.

sponds precisely ,tothe requirements of the pump 18... Since .the sump 21 is small in volume in comparison with .anynormal .rate of flow of water over the ledge 15,-. the.level .23..of thesump isextrasensitive to such rate of. flow. A substantial change in this level 23 will be causedby ,even :a slight change in how of water over the ledge 15,.suchf as mayt becaused by a loss in height of the sur face '16 ?off atfewthousandthsof an inch. Accordingly, thfldat yalve 24 can be of ordinary constructiom: and-g yet-thefloatv 25 operating the valve will effectively provide insured that'thepump water admitted to the'sump '21 *bythe external supply eventually finds its way into "the'main' body of 7 water '11;

thereby tending to increase the level :16: Theexternal' supplythus brings the systemflto ledge is increased"to"an"amouiit* such that the" rateofQ supplying external water into the sump 21' togeth'e'r'with gutter '14 cones onds-td-theratef of'withdrawai "ofwater" fromthe sump 21 by thepump '18? Thelevelbfthe".

surface 16 is then maintained at a height to produce the? stantially to the capacity 'of th'e pump-1s: Since p the pr'oper volume of water for the systemg If'ft he valve 32 is-opened during the operation of :them

skiihmingsystem precisely theQsame skimming action results. A portion ofthe'pur'np capacityis then used":

'for recirculating water from'the bottom.-.of the pool 10;

andlnot all .'of.the pump capacity is useful for withdraw, ing. .wate r fromtthe-sump 21 and keeping the leveled water in the pool 10 above the skimming ledge. Thecom, bined settingof. the valves 39 and 32 determines the. rate ofiawithdrawal'of water. from thesump 21 for a-givemr;

operating condition of the pump 18. The combined-set-z tings-of thehvalves 30' and '32 determines the: skimming rate, ratherth'an the valve 30 alone. 7 V It has. beenassumed that the external supply line-2'6 is capable of a sufiicientfiow rate to prevent a material dropin the -levelfof=water in the sump 21 below the cut ofi posit ion"of=the flo'at 25; The supply 'line20, however; may not-b suflicient' .to meet highv requirements of the pump"18'to maintain a charge for it, especially arise 18 always has asupply pfwaterfrom the sumpfZIQfWhich consistent-water from the ledge 15 and from the external level of the water 11 of the po0ll10 islower .thanthe ledge-15;": For the purposeof insuring that the pump 18 always has a suflicient charge of water, despite a small supply conduit 20, a plug valve construction 26 is carried by a stem 27 secured to the float 2 3. The plug 26 has a series of angularly spaced longitudinal grooves 28, permitting only a restricted passage of water into the conduit 17 and to the pump 18 when the plug 26 is positioned at the inlet of the conduit 17. The combined area of the grooves 28 will be sufliciently small such that, when the plug is positioned, the flow to the conduit 18 is restricted to an amount at least equal to or, preferably, less than the maximum rate of supply capable of the conduit 20. Accordingly, the level of water in the sump 21 will be prevented from any further substantial lowering, and the pump 18 will have a suflicient charge of water to prevent it from operating under undesirable conditions.

For guiding the plug 26, a guide 29 dependingly carried from the plug 26 is accommodated within the conduit 17. It insures that the plug 26 will cooperate with the conduit 17 upon a drop in level 23. The guide 29 may be of any suitable form. In the present instance, it is in the form of a plurality of radial arms.

At the normal shut-ofl level 23 indicated in the drawings, the plug 26 is sufliciently above the conduit 17 such that it will not materially influence the rate of flow from the sump 21, such as was first described.

In the form illustrated in Figs. 6 and 7, a slightly different construction is shown for insuring a sufficient charge of water for the pump 18.

In the present case, a conduit 33 is provided in place of conduit 17. This conduit 33 extends upwardly from the bottom of the sump 21. A butterfly valve 34 within the conduit 33 has secured thereto a stem 35 extending through and beyond appropriate apertures 36 of the conduit 33 for pivotally mounting the valve 34.

The plane of the butterfly valve normally extends longitudinally of the conduit 33, but may be adjusted about the "axis of the stem 35 to provide a reduced rate of flow from the sump 21 upon a substantial drop in the level 23. For this purpose, a crank arm 37 has one end carried by the stem 35 for rotation therewith. The other end of the crank arm is secured to the float 25 by a chain 38. For mounting the chain to the arm 37, a bolt 39 is provided that is threadedly carried by the arm 37 and about which a link of the chain extends. On the other end of the stem 35, a crank arm 40, similar to crank arm 37, is provided. This crank arm 40 is secured to the stem 35 for rotation therewith. A weight 41 appropriately carried by the arm 40, as illustrated in Fig. 7, is so positioned on the shaft with respect to the chain mounting 39, such as to maintain the chain 38 taut for all positions of the float 25.

If the level 23 in the sump decreases materially, the operating mechanism for the butterfly valve 34 causes the plane of the valve 34 to "be transverse to the length of the conduit 33, thereby reducing the apparent capacity of the pump 18 and insuring a charge for the pump 18.

At a horizontal position of the butterfly valve 34, corresponding to maximum throttling, there is a sufficient passage of Water around the periphery of the valve 34 to permit a limited flow of water.

Even with a restricted flow to the pump 18, such as is permitted by the plug 26 or valve 34, the level of the pool 10 will ultimately rise such as to provide a flow of water into the sump 21 from over the skimming ledge. When a sufiicient amount of water has been added to the system, the level of water in the sump 23 returns to at least the cut-off level of the float 25, and normal operation as above described is resumed.

The inventor claims:

1. In a circulatory system for a body of liquid in a container: a sump for receiving liquid from the container; a pump having an inlet connected to the sump and an outlet adapted to discharge into the container; a float cooperating with the liquid in the sump; a valve operated by the float for controlling an external source of liquid; said valve being operable upon a lowering of the float from a pre-determined level to introduce additional liquid into the sump; and a ported plug cooperating with said inlet and carried by said float for restricting the flow of liquid into said inlet upon a lowering of the level of liquid in the sump in a pre-determined'amount.

2. In a circulatory system for a body of liquid in a container: a sump for receiving liquid from the container; a pump having an inlet connected to the sump and an outlet adapted to discharge into the container; a float cooperating with the liquid in the sump; a first valve operated by the float for controlling an external source of liquid; said first valve being operable upon a lowering of the float from a pre-determined level to introduce additional liquid into the sump; and a second valve cooperable with said inlet, said second valve approaching closed position upon a lowering of the level of liquid in said sump.

References Cited in the file of this patent UNITED STATES PATENTS 1,144,327 Greth June 22, 1915 1,563,850 Hartman Dec. 1, 1925 1,670,094 Becker May 15, 1928 1,800,378 Everson Apr. 14, 1931 1,979,623 Hunter Nov. 6, 1934 2,162,074 Everson June 13, 1939 2,502,052 Landon et al Mar. 28, 1950 FOREIGN PATENTS 106,921 Australia Mar. 14, 1939 450,578 Great Britain July 21, 1936 461,828 Great Britain Feb. 25, 1937

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1144327 *Feb 24, 1915Jun 22, 1915John C W GrethAutomatic purifier for swimming-pools.
US1563850 *Apr 22, 1922Dec 1, 1925Electric Water Sterilizer AndSwimming pool
US1670094 *Apr 4, 1927May 15, 1928S L KringSwimming pool
US1800378 *Feb 23, 1929Apr 14, 1931Everson Filter CompanyCirculating water-level control
US1979623 *May 31, 1930Nov 6, 1934Hunter Frank BRecreation pool
US2162074 *Apr 22, 1936Jun 13, 1939Blair Everson RoyNonsiphoning swimming pool treatment system
US2502052 *Nov 21, 1947Mar 28, 1950Landon Standard PoolsWater recirculating system for swimming pools
AU106921B * Title not available
GB450578A * Title not available
GB461828A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2904062 *Nov 12, 1957Sep 15, 1959Lindsay CompanyFloat valve
US2974526 *Feb 11, 1959Mar 14, 1961Sun Oil CoCompensating capacitor for liquid level measurement
US3067879 *Feb 2, 1959Dec 11, 1962Swimquip IncSkim tank
US3078472 *Aug 21, 1961Feb 26, 1963Salisbury Mack LSwimming pool
US3139628 *May 9, 1960Jul 7, 1964Richards John AAutomatic water refill system for swimming pool
US3314543 *Oct 18, 1963Apr 18, 1967Jacuzzi Bros IncCleaning system installation for swimming pools
US3366063 *Feb 1, 1966Jan 30, 1968Robert A. CottrellControl system for well production line
US3386107 *Jan 5, 1966Jun 4, 1968George R. Whitten Jr.Level control and circulation system for swimming pools
US3391411 *Oct 27, 1965Jul 9, 1968Anthony S. Miller Jr.Whirlpool bath
US3432867 *Jul 13, 1967Mar 18, 1969George R Whitten JrGutter and water supply system for swimming pools
US3532217 *Apr 9, 1969Oct 6, 1970Richards George BLiquid level control system
US3537111 *Jun 25, 1969Nov 3, 1970Whitten George R JrSystem for controlling water level and recirculation in swimming pools with gutters
US3602922 *Dec 22, 1969Sep 7, 1971Broughton CorpAutomatic lavatory system for sewage disposal pumping unit
US3739405 *Feb 7, 1972Jun 19, 1973Schmidt CWater level maintenance device for swimming pools
US3837015 *Aug 14, 1972Sep 24, 1974Baker Hydro IncWater level control for swimming pool
US3908204 *Sep 6, 1974Sep 30, 1975Charles L HopkinsElectronic water closet controller
US3997925 *May 21, 1975Dec 21, 1976Hough William DApparatus to control the water level in a swimming pool
US4014052 *Feb 26, 1976Mar 29, 1977Meridian Industries, Inc.Apparatus for maintaining a predetermined liquid level
US4211249 *Sep 7, 1978Jul 8, 1980Fluid Device CorporationLiquid level control system
US4373220 *Jan 26, 1981Feb 15, 1983Selsted Walter TPool water level maintenance apparatus and method
US4485802 *Nov 9, 1981Dec 4, 1984Babcock Horace WSolar heater for swimming pools
US4498984 *Jan 30, 1980Feb 12, 1985Colson Andrew ESecondary water chamber with pump and filter
US4621657 *Apr 10, 1985Nov 11, 1986Roto Moulded Plastics Pty. LimitedAutomatic water level monitoring system
US4622991 *Mar 13, 1984Nov 18, 1986Norbert TunzeEvaporation sensor for an aquarium
US4836239 *Feb 5, 1988Jun 6, 1989Kinkead Clifford WWater cooling tower and water level control system therefor
US4837870 *Jun 8, 1987Jun 13, 1989Wiley Robert BSpa overflow system
US4944506 *Nov 18, 1988Jul 31, 1990Edmonds Medical Systems, Inc.Exercise device with underwater treadmill
US5108088 *Jul 30, 1990Apr 28, 1992Stewart Medical, Inc.Exercise device with underwater treadmill
US5154205 *Jan 3, 1992Oct 13, 1992Langill Edwin RMethod and apparatus for maintaining level of water in above-ground swimming pools
US5255703 *Jul 8, 1992Oct 26, 1993Johnson Dwight NFloat operated fill valve
US5367723 *Feb 25, 1993Nov 29, 1994Pleva Plumbing & Heating, Inc.Valve for regulating water level in a swimming pool
US5649330 *Apr 24, 1995Jul 22, 1997Lind; Alan R.Heated flexible bathing container
US5655232 *Jun 7, 1995Aug 12, 1997Buckwalter; James K.Fluid level control device and method
US5755257 *Apr 27, 1995May 26, 1998Bgu Baugesellschaft Fur Umweltschutzanlagen MbhRetention gate
US5862545 *Sep 16, 1997Jan 26, 1999Mathis; Cleo D.Pressurized flow self-cleaning whirlpool tub system
US6000425 *Sep 1, 1998Dec 14, 1999Steinorth; Jeffry H.Automatic remote fluid level controller
US6012481 *Jul 18, 1997Jan 11, 2000Lenart; John J.Constant-level fluid supplier
US6228272Mar 10, 1998May 8, 2001GOLA ANDRéMethod and device for disinfecting pool water in a branched circuit thereof
US6766614 *Aug 26, 2002Jul 27, 2004George R. TeufelAutomatic liquid dispensing device with smart properties
US6895990 *Aug 25, 2004May 24, 2005James H. CarrollWater heater fail safe apparatus
US7059342 *Mar 4, 2003Jun 13, 2006James Jerome CrimminsLiquid shut-off system
US7934517 *Dec 28, 2007May 3, 2011Mp Industries, Inc.Water level control system
US8875731 *Sep 24, 2009Nov 4, 2014David LarsenAutomatic water leveler
US20100071123 *Sep 24, 2009Mar 25, 2010David LarsenAutomatic water leveler
WO1985004735A1 *Apr 10, 1985Oct 24, 1985Roto Moulded Plastics Pty LtdAutomatic water level monitoring system
WO1998040585A1 *Mar 10, 1998Sep 17, 1998Philippe BillaudMethod for servicing the water of a swimming pool and device for implementing same
WO2007068660A1 *Dec 8, 2006Jun 21, 2007Electricite De FranceInstallation for practising whitewater activities
U.S. Classification210/127, 137/399, 210/167.12, 137/428, 210/205, 4/509, 210/114, 4/302
International ClassificationG05D9/02, E04H4/12, E04H4/00, G05D9/00
Cooperative ClassificationE04H4/12, G05D9/02
European ClassificationG05D9/02, E04H4/12