Electrolytic pool chlorinator having baffled cathode chamber into which chlorinated water is delivered

An electrolytic pool chlorinator produces chlorinated pool water that is added to the cathode chamber to continuously dilute the caustic concentration of the catholyte before being returned to the pool. The cathode chamber includes a series of baffle plates between the primary cathode and the chlorinated pool water entry port in order to maintain the hydroxyl ion concentration near the primary cathode high enough to provide good current efficiency, yet low enough to avoid significant back-migration of hydroxyl ions. The baffle plates also cause metal hardness ions such as calcium to precipitate before reaching the primary cathode. A negatively-charged second cathode spaced apart from the primary cathode also helps to prevent precipitation of metal hardness ions upon the primary cathode. The chlorinator is provided with a feeder tank including a float-controlled valve having a leveraged flexible elongated seal that cooperates with a flared channel to regulate the flow of chlorinated pool water to the suction side of the pool pump. A catholyte access pipe extends from the upper portion of the chlorinator to the cathode chamber in the lowermost portion of the chlorinator to allow a user to flush water, acid, or brine therethrough. A thermostatic switch detects the stoppage of pool water flowing into the chlorinator and disconnects electrical power from both the chlorinator and the pool pump in response thereto.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to electrolytic pool chlorinators 
for chlorinating a pool of water, and more particularly, to an 
electrolytic pool chlorinator having a baffled cathode chamber into which 
chlorinated pool water is delivered for preventing caustic concentrations 
within the catholyte from becoming excessively high while maintaining good 
current efficiency and rapid start-up. 
2. Description of the Prior Art 
Electrolytic pool chlorinators are well known in the art and are 
exemplified by the apparatus described in U.S. Pat. Nos. 914,856, issued 
to Meyer; 3,223,242, issued to Murray; 4,229,272, issued to Yates; 
4,129,493, issued to Tighe, et al.; 4,136,005, issued to Persson, et al.; 
4,290,873, issued to Weaver; 4,500,404, issued to Tucker; 3,563,879, 
issued to Richards, et al.; as well as U.S. Pat Nos. 4,472,256 and 
4,599,159 issued to the present applicant. Such electrolytic pool 
chlorinators generally operate by electrolyzing a sodium chloride brine 
solution contained within an anode chamber, attracting positively-charged 
sodium ions to a negatively-charged cathode, and attracting 
negatively-charged chloride ions to the positively-charged anode, thereby 
liberating chlorine gas at the anode. The chlorine gas released thereby 
may then be used to chlorinate the water within a swimming pool, spa or 
the like. 
The anode and cathode chambers of such an electrolytic pool chlorinator are 
typically separated from one another by an ion-permeable barrier to 
prevent the chlorine gas liberated within the anode chamber from mixing 
with the hydrogen gas liberated in the cathode chamber and to physically 
separate the sodium chloride (or brine) anolyte solution within the anode 
chamber from the sodium hydroxide (caustic soda) catholyte solution within 
the cathode chamber. The ion-permeable membrane is permeable to positive 
ions, such as sodium ions formed within the anode chamber, but presents a 
barrier to the passage of negative ions, such as hydroxyl ions, present 
within the cathode chamber, at least at relatively low concentrations of 
such hydroxyl ions. 
Ion selective membranes used to separate the anode and cathode cells, such 
as "NAFION" brand perfluorosulfonic acid membrane commercially available 
from E. I. DuPont de Nemours and Company of Wilmington, Del., form 
imperfect ion barriers. Hydroxyl ions within the catholyte can migrate 
through such ion selective membranes into the anolyte both during periods 
when the chlorinator is operating, as well as during periods when the 
chlorinator is shut off. As the concentration of hydroxyl ions within the 
catholyte becomes greater, back-migration of hydroxyl ions through the ion 
permeable selective membrane increases. If the sodium hydroxide 
concentration with the catholyte accumulates to within the range of 15% to 
20%, the back-migration of hydroxyl ions into the anolyte is approximately 
10% of the total number of hydroxyl ions within the catholyte during 
chlorinator operation. By comparison, dropping the sodium hydroxide 
concentration of the catholyte to the range of 1%-3% decreases the rate of 
back-migration of hydroxyl ions to approximately 2%. While the rate of 
back-migration of hydroxyl ions is lessened when the chlorinator is shut 
off, migration of hydroxyl ions into the anolyte during shut off is still 
significant, particularly since an electrolytic pool chlorinator used with 
a typical backyard swimming pool is shut off for greater periods of time 
each day then it is turned on. 
Back-migration of hydroxyl ions into the anolyte is undesirable for several 
reasons. Hydroxyl ions passing into the anolyte initially form 
hypochlorites and, in a subsequent step, form chlorates, such as sodium 
chlorate (NaClO.sub.3) in the anolyte. Such chlorates accumulate over time 
within the brine solution, and, at very high concentrations, form a 
chlorate-saturated brine solution which reduces the amount of sodium 
chloride that can be dissolved within the anolyte, thereby minimizing 
further chlorine production. Furthermore, passage of hydroxyl ions into 
the anolyte reduces chlorine gas production because chlorine which 
combines with hydroxyl ions to form hypochlorites is prevented from being 
liberated as chlorine gas. In addition, the presence of hydroxyl ions 
within the anolyte can lead to passivation of the dimensionally stable 
anode material resulting from increased oxidation which occurs at high pH 
within the anolyte. Hydroxyl ions within the anolyte also contribute to 
the formation of calcium deposits upon the anode side of the ion-permeable 
membrane, which deposits lead to the plugging of the membrane and a 
corresponding reduction in the efficiency of the chlorinator. 
In U.S. Pat. No. 4,040,919 issued to Eng, it is proposed that hydrochloric 
acid be periodically added to the anolyte for eliminating chlorates and 
dissolving calcium deposits upon the ion permeable membrane. However, the 
addition of hydrochloric acid to the chlorates within the anolyte 
instantly produces large quantities of poisonous chlorine gas, and is 
therefore a dangerous procedure to perform. The typical owner of a 
backyard swimming pool could not be expected to add acid to the anolyte in 
the manner taught by Eng without posing a substantial safety risk. 
Within applicant's U.S. Pat. No. 4,599,159, an electrolytic pool 
chlorinator is disclosed wherein pool water is continuously delivered to 
the cathode chamber at a point relatively remote from the cathode to 
continuously dilute the catholyte. An overflow conduit communicating with 
the cathode chamber continuously drains catholyte from the cathode chamber 
to prevent excess concentrations of sodium hydroxide from accumulating 
therein. While maintaining a relatively low sodium hydroxide concentration 
within the cathode chamber minimizes undesired back-migration of hydroxyl 
ions into the anolyte, the reduced hydroxyl ion concentration in the 
catholyte causes the chlorinator to take longer to start up after it has 
been shut off for a period of time, since there are relatively few ions in 
the vicinity of the cathode upon initial start-up which can conduct an 
electrical current. In contrast, a higher concentration of hydroxyl ions 
in the catholyte increases the electrical conductivity thereof and results 
in more efficient short term chlorine production. Moreover, if the 
concentration of sodium hydroxide within the catholyte is very low, then 
any metal hardness ions (such as calcium or magnesium) introduced into the 
cathode chamber (as by the addition of pool water thereto) are more likely 
to reach the cathode and/or ion permeable membrane before such metal 
hardness ions precipitate out as a deposit. Such precipitates include 
calcium carbonate (CaCO.sub.3), calcium hydroxide (Ca(OH).sub.2), and 
magnesium hydroxide (Mg(OH).sub.2), and are more likely to form deposits 
at the higher pH conditions proximate the cathode. Such deposits upon the 
cathode and/or membrane reduce the efficiency of the chlorinator and 
require more frequent maintenance. 
Accordingly, it is an object of the present invention to provide an 
electrolytic pool chlorinator which minimizes back-migration of hydroxyl 
ions from the catholyte into the anolyte, while at the same time, 
maintaining a sufficiently high concentration of hydroxyl ions in the 
vicinity of the cathode to permit quick start-up following periods when 
the chlorinator is shut off and permitting good electrical conductivity 
for efficient chlorine production. 
It is another object of the present invention to provide such a chlorinator 
which prevents excessive concentrations of hydroxyl ions from accumulating 
within the catholyte while simultaneously minimizing the possibility of 
metal hardness ions within the catholyte from precipitating out and 
depositing upon the cathode and/or ion permeable membrane. 
It is a further object of the present invention to permit the use of 
relatively hard pool water to dilute the catholyte while avoiding deposits 
of metal hardness ion compounds upon the cathode and/or ion permeable 
membrane, despite the relatively high concentrations of metal hardness 
ions typically present within such pool water. 
It is a still further object of the present invention to provide an 
electrolytic chlorinator that is relatively free of routine maintenance at 
frequent intervals. 
As mentioned above, the formation of metal hardness deposits upon the 
cathode are to be avoided in order to maintain good electrical 
conductivity for the chlorinator. Nonetheless, some metal hardness ions 
added to the catholyte tend to diffuse toward the vicinity of the cathode. 
Metal hardness ion deposits, such as calcium hydroxide (Ca(OH).sub.2) and 
magnesium hydroxide (Mg(OH).sub.2), are particularly a problem when pool 
water is used to dilute the catholyte, since pool water typically contains 
from 300 to 2000 parts per million of calcium and magnesium. 
It is therefore another object of the present invention to reduce the 
likelihood that any metal hardness ions reaching the vicinity of the 
cathode will precipitate out and deposit upon the cathode. 
As explained above, were chlorates to form and accumulate within the anode 
chamber, the efficiency of the chlorinator would be reduced. In addition, 
metal hardness ions within the anolyte can be precipitated as deposits 
upon the ion permeable membrane, plugging the membrane and further 
reducing the efficiency of the chlorinator. While such accumulations of 
chlorates and metal hardness ions can be eliminated by periodic draining 
of the brine tank, this would require the operator to perform additional 
maintenance steps. 
It is therefore a further object of the present invention to provide an 
electrolytic chlorinator which serves to prevent accumulations of 
chlorates and metal hardness ions within the anolyte without requiring the 
operator to perform additional maintenance steps beyond merely refilling 
the brine tank with salt. 
When chlorine gas is reacted with pool water to chlorinate the same, both 
hypochlorous acid and hydrochloric acid are produced. Hypochlorous acid is 
a desired sanitizing agent which kills bacteria and algae in the pool 
water. On the other hand, hydrochloric acid merely tends to lower the pH 
of the pool water. While it may be advantageous to briefly maintain 
chlorinated pool water at a lowered pH to superchlorinate the water, pool 
water maintained at a pH below 7.0 can cause swimmer discomfort and can 
cause corrosion of metal fixtures. 
Accordingly, it is another object of the present invention to provide such 
an electrolytic pool chlorinator wherein hydrochloric acid produced upon 
reaction of chlorine gas with pool water is at least partially neutralized 
before being returned to the pool. 
While some electrolytic pool chlorinators are installed at the time that 
the swimming pool is constructed, it is more often the case that such 
electrolytic pool chlorinators are installed with existing swimming pool 
equipment. For new swimming pool installations, a gravity feed line can be 
installed from the outlet of the chlorinator to the skimmer of the pool in 
order to permit chlorinated water to drain back to the pool under the 
force of gravity. However, when an electrolytic pool chlorinator is added 
to existing swimming pool equipment, gravity feed of the chlorinated water 
output from the chlorinator back to the pool is often not possible without 
breaking the concrete pool decking surrounding the pool in order to lay 
such a gravity feed line back to the pool. In such cases, it is possible 
to return the chlorinated water to the swimming pool by coupling the 
outlet of the chlorinator to the suction side of the pool pump. However, 
one disadvantage of this technique is that the pool pump can lose its 
prime if, for some reason, the flow of chlorinated water produced by the 
electrolytic pool chlorinator is either interrupted while the pool pump is 
operating or is of a lesser flow rate than the rate at which such 
chlorinated water is being suctioned back to the pump. If air permitted to 
enter the pool pump instead of chlorinated water, the pump may lose its 
prime. 
Accordingly, it is an object of the present invention to provide an 
electrolytic pool chlorinator having a chlorinated water outlet that can 
be coupled to the suction inlet of the pool pump for returning chlorinated 
water to the pool without permitting the pool pump to lose its prime. 
In designing an electrolytic pool chlorinator, it is desirable to locate 
the cathode chamber at a lowermost point within the chlorinator housing so 
that the upper portion of the chlorinator can be utilized to store salt 
and water to form the brine solution supplied to the anode chamber. The 
larger the space available to fill the brine tank of the chlorinator with 
water and salt, the less often that the user needs to add salt or water 
thereto. On the other hand, after long periods of operation, the cathode 
chamber may need to be rejuvenated, as by addition acid to remove any 
deposits which may have formed over extended periods within the cathode 
chamber. In known electrolytic pool chlorinators, such servicing of the 
cathode chamber is difficult and typically requires that the chlorinator 
be disassembled in order to gain access to the cathode chamber. Such 
disassembly typically requires that the brine tank first be drained, 
thereby wasting the contents thereof. In addition, during colder winter 
month, it is desirable to fill the cathode chamber with brine in order to 
lower the freezing point of the catholyte. In known electrolytic pool 
chlorinators, there is no simple way to add either acid or a brine 
solution to the cathode chamber for the purposes described above. 
Accordingly, it another object of the present invention to provide an 
electrolytic pool chlorinator including a cathode chamber formed adjacent 
the lowermost region of the chlorinator housing to maximize the space 
available to store salt for forming brine, while simultaneously providing 
easy access to the interior of the cathode chamber for periodic removal of 
hardness deposits therein and for adding brine to winterize the unit. 
Applicant's prior U.S. Pat. No. 4,599,159 discloses a safety feature for 
switching off the electrical power supply of the electrolytic pool 
chlorinator upon detecting a stoppage in the flow of pool water that is 
normally fed to the chlorinator for intermixing with the chlorine gas 
produced thereby. Upon detecting a stoppage in the flow of pool water, the 
electrical power supply of the chlorinator is switched off to prevent any 
further generation of chlorine gas until pool water is again supplied to 
the chlorinator. However, the thermostatic switch disclosed in applicant's 
prior U.S. Pat. No. 4,599,159 serves only to switch off the supply of 
electrical power to the chlorinator; the supply of electrical power 
provided to the pool pump motor is totally independent from such 
thermostatic switch, and accordingly, the pool pump motor continues to be 
supplied with electrical power even though the chlorinator has been turned 
off by the thermostatic switch, and even though the pool pump has stopped 
circulating pool water. However, continued application of electrical power 
to the pool pump motor for an extended time after the pump has either 
failed or lost its prime can result in damage to the pump. 
Accordingly, it is a further object of the present invention to provide an 
electrolytic pool chlorinator adapted to help prevent damage to the pool 
pump upon detecting a stoppage in the flow of pool water ordinarily 
supplied to the chlorinator. 
These and other objects of the present invention will become more apparent 
to those skilled in the art as the description thereof proceeds. 
SUMMARY OF THE INVENTION 
Briefly described and in accordance with one embodiment thereof, the 
present invention relates to an electrolytic pool chlorinator having anode 
and cathode chambers divided by an ion permeable selective membrane, the 
chlorinator further including a cathode located proximate to the ion 
permeable membrane and a baffle disposed in the cathode chamber between 
the cathode and a region of the cathode chamber remote from the cathode. A 
mechanism for diluting the catholyte is connected with the cathode 
chamber, preferably remote from the cathode, for adding water having a 
relatively low hydroxyl ion concentration to the catholyte and for 
draining catholyte from the cathode chamber to continuously remove 
hydroxyl ions from the catholyte. The baffle regulates the diffusion rate 
of hydroxyl ions from the region of the catholyte surrounding the cathode 
toward the catholyte dilution mechanism. The baffle maintains a 
sufficiently high concentration of hydroxyl ions proximate the cathode to 
permit good current conductivity when the chlorinator is operated, yet 
prevents the hydroxyl ion concentration within the catholyte in the region 
of the cathode from becoming high enough to cause significant amounts of 
back-migration of hydroxyl ions through the ion-permeable membrane and 
into the anolyte. 
In one embodiment of the present invention, the aforementioned baffle may 
be of the form of a second or auxiliary cathode spaced apart from the 
primary cathode to divide the primary cathode from remote portions of the 
cathode chamber with which the catholyte dilution mechanism is 
interconnected. The auxiliary cathode has openings formed therein and may 
be sized somewhat smaller than the cross-sectional dimensions of the 
cathode chamber to permit hydroxyl ions to slowly diffuse from the region 
surrounding the primary cathode toward the catholyte dilution mechanism. 
The auxiliary cathode may be negatively-charged, like the primary cathode, 
for allowing the front and rear faces of the auxiliary cathode to attract 
any positively-charged metal hardness ions which reach the vicinity of the 
primary cathode; consequently, only one-third as many metal hardness ions 
can become deposited upon the primary cathode. 
Within another embodiment of the present invention, the aforementioned 
baffle takes the form of an upper baffle disposed within the cathode 
chamber and extending substantially laterally thereacross, the upper 
baffle extending downwardly into the catholyte to a first predetermined 
depth. A lower baffle is also disposed within the cathode chamber and 
extends substantially laterally thereacross, generally parallel to but 
spaced somewhat apart from the upper baffle. The lower baffle extends 
upwardly from the floor of the cathode chamber into the catholyte to a 
height substantially near the aforementioned first predetermined depth in 
order to control the rate at which hydroxyl ions within the catholyte 
migrate from the region surrounding the cathode toward the catholyte 
dilution mechanism. An additional baffle may also be provided in order to 
help prevent any metal hardness ions from the region of the cathode 
chamber near the cathode or ion permeable membrane. The additional baffle 
extends substantially parallel to and spaced apart from the lower baffle 
and extends upwardly beyond the level of the catholyte and downwardly to a 
point just above the floor of the cathode chamber. Any metal hardness ions 
diffusing upwardly between the additional baffle and the lower baffle 
toward the cathode encounter hydroxyl ions diffusing downwardly toward the 
dilution mechanism downwardly toward the cathode chamber floor precipitate 
out before passing over the edge of the lower baffle. 
The catholyte dilution mechanism includes a source of pool water tending to 
raise the fluid level of the catholyte within the cathode chamber. An 
outflow pipe drains off excess catholyte extending above a predetermined 
catholyte fluid level, the outlet pipe preferably having an inlet end 
positioned near the floor of the cathode chamber for drawing in any 
precipitated compounds falling toward the cathode chamber floor. The 
source of the pool water admitted into the cathode chamber includes a 
metering cup for metering a substantially constant inflow of pool water to 
the catholyte despite variations in the rate at which pool water is 
supplied to the metering cup; pool water supplied by the metering cup 
dilutes the catholyte at a substantially uniform rate, and thereby 
maintains the hydroxyl ion concentration of the catholyte in the vicinity 
of the cathode at a substantially constant value. 
Another aspect of the present invention relates to the use of chlorinated 
pool water, containing hypochlorous acid and hydrochloric acid, as the 
diluent for the catholyte. The electrolytic pool chlorinator includes a 
device for reacting the chlorine gas with pool water to form hypochlorous 
acid and hydrochloric acid which is then introduced into the cathode 
chamber by the catholyte dilution mechanism; the chlorinated pool water 
dilutes the catholyte and simultaneously lowers the hydroxyl ion 
concentration thereof through the reaction of hydrochloric acid with 
sodium hydroxide to form ionized sodium chloride and water. Excess 
catholyte drained from the cathode chamber by the catholyte dilution 
mechanism is returned to the pool of water, including the hypochlorous 
acid dissolved therein. By reacting the hydrochloric acid formed when the 
chlorine gas is intermixed with pool water with the sodium hydroxide 
produced as a byproduct in the cathode chamber during the electrolytic 
reaction, the chlorinated water returned to the pool by the feeder tank is 
essentially pH neutral. Moreover, by lessening the hydroxyl ion 
concentration within the catholyte through the chemical reaction of sodium 
hydroxide with hydrochloric acid, the pH of the catholyte is retained at a 
lesser value, further minimizing the likelihood of precipitation of metal 
hardness ions within the cathode chamber. 
Another aspect of the present invention relates to the provision of a 
chlorinator having a feeder tank including a novel valve structure for 
permitting chlorinated water within the feeder tank to be returned to the 
suction side of the pool pump at a controlled rate and without causing the 
pool pump to lose its prime. The feeder tank includes a base and upwardly 
extending side walls to form a tank for containing the chlorinated water. 
The base includes a substantially planar, upwardly facing sealing surface 
extending between first and second opposing ends and having a flared 
opening extending therethrough downwardly into the base. The flared 
opening is relatively narrow and shallow adjacent a first end of the 
sealing surface and gradually extends wider and deeper toward the second 
end of the sealing surface, where it terminates in a bore formed through 
the base. An outlet extends from the base in fluid communication with the 
bore for being coupled to the suction inlet of the pool pump. A flexible, 
elastomeric planar seal extends between first and second opposing ends, 
the first ends of the seal being secured to the second end of the planar 
sealing surface of the base adjacent the wider and deeper end of the 
aforementioned flared opening. A float is secured to the second end of the 
flexible planar seal proximate the narrower and shallower portion of the 
flared opening. As the feeder tank fills with water, the float lifts the 
second end of the planar seal off of the first end of the planar sealing 
surface to expose the narrow, shallow portion of the flared opening. As 
the water level rises further within the feeder tank, the float gradually 
peels the flexible seal off the planar sealing surface to expose greater 
amounts of the flared opening, thereby permitting chlorinated water to be 
withdrawn from the feeder tank at a faster flow rate. When the level of 
chlorinated water within the feeder tank falls to a low level, the 
flexible seal covers the entire length of the flared opening, thereby 
preventing additional chlorinated water or air from being drawn into the 
pool pump. 
Another feature of the present invention is an electrolytic pool 
chlorinator which provides convenient access to the cathode chamber for 
periodic servicing without requiring disassembly of the chlorinator, while 
maximizing the volume available for the storage of salt within the 
chlorinator housing in order to form the brine solution. The cathode 
chamber is disposed proximate to the floor of the outer housing of the 
chlorinator, and the cathode chamber includes a ceiling dividing the 
cathode chamber from the salt storage volume of the chlorinator housing 
and partially supporting salt stored therein. The outer housing of the 
chlorinator includes a removable upper cover and a cathode access pipe 
extends generally vertically within the chlorinator from a point just 
below the removable cover to a lower end which passes through the ceiling 
of the cathode chamber in fluid communication with the cathode chamber. 
When servicing the cathode chamber, water may be poured into the upper end 
of the cathode access pipe to flush the catholyte from the cathode 
chamber, and acid may then be poured into the cathode access pipe to 
dissolve and remove any hardness deposits which have formed over time 
within the cathode chamber. Additional water may be poured into the 
cathode access pipe to flush the acid from the cathode chamber. As fluids 
are poured into the cathode access pipe, an equivalent amount of fluid 
overflows out of the cathode chamber through the above-described outflow 
pipe. During winter months, a brine solution may be poured into the 
cathode access pipe to lower the freezing point of the catholyte. 
It will be recalled that one of the objects of the present invention is to 
provide a chlorinator which periodically flushes chlorates, metal hardness 
ions, and other contaminants from the anolyte without requiring the user 
to perform maintenance beyond merely refilling the brine tank with salt. 
Accordingly, the chlorinator of the present invention includes an anode 
access pipe which has a lower end in fluid communication with the anode 
chamber and an upper end having an overflow opening at a first 
predetermined height. The chlorinator includes a mechanism for maintaining 
the fluid level in the brine tank at a second predetermined height below 
the first predetermined height at which the aforementioned overflow 
opening is located. The chlorinator further includes a flow path coupling 
the overflow opening of the anode access pipe to the cathode chamber. Each 
time the user refills the brine tank with salt, contaminated anolyte 
displaced by the additional salt rises within the anode access pipe and 
overflows through the overflow opening into the cathode chamber; such 
contaminants are eventually diluted within the cathode chamber and drained 
to the swimming pool. The reaction column used to intermix chlorine gas 
with pool water can advantageously serve as the flow path through which 
the overflowing anolyte is directed to the cathode chamber. 
Yet another aspect of the present invention relates to the provision of an 
electrolytic pool chlorinator which disconnects electrical power from the 
pool pump motor upon detecting a stoppage in the flow of pool water 
normally supplied to the chlorinator. The chlorinator includes an inlet 
coupled to the pool pump for receiving a stream of pool water therefrom. 
The pool water received by the chlorinator inlet is caused to flow through 
a metal conduit before being combined with the chlorine gas liberated by 
the chlorinator. A heat source is positioned in thermal contact with the 
aforementioned metal conduit, as is a thermostatic switch. The 
thermostatic switch is closed for connecting alternating current 
electrical power to the electrical power supply for the chlorinator when 
the temperature of the aforementioned metal conduit is below a 
predetermined temperature. When the temperature of the aforementioned 
metal conduit rises above the predetermined temperature, the thermostatic 
switch opens, disconnecting alternating current electrical power from the 
electrical power supply of the chlorinator. The chlorinator power supply 
includes an output terminal electrically coupled to the side of the 
thermostatic switch that is also coupled to the electrical power supply of 
the chlorinator, and a wire is interconnected between the aforementioned 
output terminal and a power input terminal of the electric motor that 
powers the pool pump. When pool water stops flowing through the metal 
conduit for several minutes, the temperature of the metal conduit rises, 
causing the thermostatic switch to open. The opening of the thermostatic 
switch simultaneously disconnects electrical power from both the pool 
chlorinator as well as the pool pump motor, thereby avoiding damage to the 
pool pump which might result when the pump loses its prime for an extended 
period of time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 4, the electrolytic pool chlorinator of the present 
invention is designated generally by reference numeral 20 and includes a 
cylindrical outer housing 22, a circular floor 24, and a removable upper 
cover 26. Extending upwardly through cover 26 is a salt and water level 
indicator tube 28 having an enlarged knob 30 at the upper end thereof 
referring briefly to FIG. 13, indicator tube 28 extends downwardly into 
the interior of chlorinator housing 22 and includes a foot 32 at the lower 
end thereof for resting upon a quantity of salt deposited within 
chlorinator 20 in order to form a brine solution. The relatively height of 
indicator tube 28 thereby indicates the quantity of salt remaining within 
chlorinator 20. 
Electrical power supply housing 34 extends substantially horizontally 
through the upper portion of chlorinator housing 22, as shown in FIGS. 4 
and 13. Power supply housing 34 includes a front face place 36 form which 
extends a pool water inlet connector 38 for coupling to a pressurized 
source of pool water, in a manner described below with reference to FIGS. 
1 and 2. Pool water entering through connector 38 exits from a similar 
connector 40. Connector 40 is coupled by a tube 42 to a similar connector 
44 extending through cylindrical housing 22 into the interior of 
chlorinator 20. 
Referring briefly to FIGS. 6 and 13, pool water received by connector 38 is 
circulated through a U-shaped metal conduit extending within the 
electrical power supply 48 of the chlorinator before exiting through 
connector 40. Metal conduit 46 is used in conjunction with a resistive 
heater and a thermostatic switch, to be described below, in order to stop 
the production of chlorine gas when the flow of pool water is interrupted 
and to protect the pool pump motor against damage following a loss of 
prime of the pool pump. Metal conduit 46 may also serve as a heat sink to 
remove heat from various power supply components. Also shown in FIG. 4 
extending from the lower portion of chlorinator 20 is a chlorinated water 
outlet port 50 for discharging chlorinated pool water for return to the 
swimming pool. 
The general operation of chlorinator 20 is best understood by reference to 
FIG. 13. Chlorinator 20 includes an anode chamber designated generally by 
reference numeral 52. Anode chamber 52 is bounded by a circular anode 
chamber floor 52, a cylindrical anode chamber side wall 56, and an upper 
ceiling plate 58. Ceiling plate 58 is shown in greater detail in FIG. 11 
and includes a downwardly extending circular flange 60 which extends about 
the upper rim of cylindrical side wall 56. As shown in FIGS. 11 and 13, 
ceiling plate 58 has a relatively large opening 62 formed therein which 
opening is surrounded by a pair of upwardly extending concentric flanges 
64 and 66 defining a channel 68 therebetween. An inverted funnel-shaped 
member 70 serves as a chlorine gas collection baffle and has an outer 
diameter commensurate with that of channel 68 for permitting the 
downwardly-turned rim 72 thereof to be inserted into channel 68. As shown 
in FIG. 11, a mounting ear 74 extends from rim 72 and has a hole formed 
therein for receiving a mounting screw 76. A similar mounting ear 78 
extends from outer rim 66 of ceiling plate 58 and has a hole formed 
therein for engaging the lower tip of screw 76, thereby maintaining 
chlorine gas collection baffle 70 in position over hole 62. Gas collection 
baffle 70 includes an upwardly directed central tower 80 coupled with the 
lower end of a chlorine gas delivery tube 82. Referring to FIG. 11, the 
lower edge of downwardly turned flange 72 is of a stepped configuration 
for permitting saturated brine solution from the brine tank above baffle 
70 to pass around the peripheral edges of baffle 70 into anode chamber 52, 
while preventing solid salt particles from passing into anode chamber 52. 
Referring to FIG. 7 and FIG. 13, a cylindrical membrane/cathode support 
housing 84 extends into anode chamber 52 through side wall 56 thereof. 
Membrane/cathode support housing 84 includes a cylinder 110 having an 
externally threaded end engaged by a retaining ring 112. Also extending 
through the upper portion of cylindrical side wall 56 is a polyvinyl 
chloride (PVC) tube 86 which serves both to support anode 88 and to 
insulate a lead-in wire 90 extending between electrical power supply 48 
and anode 88. As shown in FIG. 13, PVC tube 86 initially extends 
horizontally into anode chamber 52 and then turns downwardly. Referring to 
FIG. 7, a PVC elbow connector has one port coupled to the lower end of 
tube 86 and a second port which has a fitting 94 cemented therein. A bolt 
96 extends through fitting 94 in sealing engagement therewith and further 
extends through anode 88 which is secured thereto by nuts 98 and 100. Bolt 
96 is in electrical contact with conductor 90 for imposing a positive 
electrical voltage upon anode 88. Positioned parallel to and slightly 
spaced apart from anode 88 is a NAFION brand ion permeable selective 
membrane 102 supported by an annular ring 104. An apertured circular 
spacer plate 105 made of VEXAR brand material is positioned between anode 
88 and membrane 102 to prevent the membrane from being damaged due to 
contact with anode 88. A primary cathode plate 106 is positioned parallel 
to and closely proximate membrane 102 on the side thereof opposite anode 
88. An apertured spacer plate 108 also made of VEXAR brand material is 
interposed between primary cathode 106 and membrane 102 for maintaining 
primary cathode 106 slightly spaced apart therefrom. Primary cathode 106, 
spacer 108, and membrane support ring 104 are clamped against the open end 
of cylinder 110 by internally threaded retaining ring 112 which threadedly 
engages the externally threaded end of cylinder 110. The preferred 
materials used to form anode 88, membrane 102, and primary cathode 106 are 
disclosed in applicant's prior Pat. No. 4,599,159, the disclosure of which 
is hereby incorporated by reference. 
Primary cathode 106 includes a center opening through which the shaft of 
bolt 112 extends. Bolt 112 also passes through a secondary of auxiliary 
cathode 114 spaced somewhat apart from primary cathode 106 and having a 
diameter slightly less than the internal diameter of cylinder 110. The 
shaft of bolt 112 also extends into a PVC cap 116 spaced apart from 
auxiliary cathode 114 by a spacing washing 118. Nut 120 locks cap 116, 
washer 118, auxiliary cathode 114, and primary cathode 106 together as a 
unit, and nut 122 secures to bolt 112 a conductor from insulated wire 124 
for imposing a negative voltage upon both primary cathode 106 and 
auxiliary cathode 114. The open end 126 of PVC cap 116 is then filled with 
an epoxy to seal the interior components thereof. Referring to FIG. 13, 
anode wire 90 and cathode wire 124 are routed through a hydrogen gas vent 
opening 128 in the side wall of chlorinator housing 22 and are routed 
upwardly along the exterior of chlorinator housing 22 through a wire guide 
130 (see FIG. 4) to the electrical power supply 48. 
Still referring to FIG 13, cathode chamber 130 is bounded by the lower 
floor 24 of chlorinator 20, by lower cylindrical wall 23, by inner 
cylindrical wall 56 (which divides cathode chamber 130 from anode chamber 
52), and by ceiling plate 58 (shown in FIG. 11). Cathode chamber 130 also 
includes the interior of cylinder 110 extending through cylindrical wall 
56 and containing primary cathode 106 and auxiliary cathode 114 (see FIG. 
7). A catholyte is normally maintained within cathode chamber 130 and is 
maintained at the level designated by dashed lines 132. Shown within 
cathode chamber 130 remote from primary cathode 106 is a 
vertically-oriented outflow tube 134 having an open lower end disposed 
slightly above floor 24 of cathode chamber 130. The upper end of outflow 
tube 134 is also open and terminates at a height corresponding with 
catholyte fluid level 132. The upper end of outflow tube 134 is surrounded 
by an oversizing pipe 136 having an interior diameter greater than the 
outer diameter of outflow tube 134. The lower end of pipe 136 is sealed 
against the outer surface of outflow tube 134 by an annular ring 138. The 
upper end 140 of enlarged pipe 136 is opened and extends slightly above 
the open end of outflow tube 134. Extending laterally from oversized pipe 
136 is a port collar 142 defining a horizontal bore therethrough centered 
at, or slightly below, the upper end of outflow tube 134. A crossflow tube 
144 has a first end cemented within port collar 142 and a second end which 
extends through lower cylindrical wall 23, terminating in chlorinated pool 
water outlet 50. The addition of any fluid to cathode chamber 130 tends to 
cause catholyte level 132 to rise, but a corresponding amount of fluid 
spills over the upper end of outflow tube 134 and out of chlorinator 20 
through crossflow tube 144. 
As mentioned above, electrolytic pool chlorinators produce chlorine gas by 
electrolyzing a sodium chloride brine solution within the anode chamber, 
attracting positively-charged sodium ions towards the negatively-charged 
cathode while attracting negatively-charged chlorine ions to the 
positively-charged anode, thereby liberating chlorine gas within the anode 
chamber. The passage of positively charged sodium ions through the ion 
permeable membrane into the cathode chamber causes water within the 
cathode chamber to dissociate into negatively-charged hydroxyl ions and 
positively-charged hydrogen ions liberated from the cathode as hydrogen 
gas. 
The brine solution supplied to anode chamber 52 is formed by depositing a 
quantity of salt within chlorinator 20 upon ceiling plate 58 to an initial 
level designated by dashed line 148. The volume enclosed by cylindrical 
side walls 22 and 21 and ceiling plate 58 forms a brine tank 150 which 
continuously supplies a saturated brine solution to anode chamber 52. 
Water is supplied to brine tank 150 in order to maintain the water level 
therein at the level designated by reference numeral 152. Referring 
briefly to FIG. 14, a float operated valve assembly 154 includes a valve 
body 156 extending through cylindrical side wall 22 and including an 
external connector 158 coupled to a tap water supply tube 160 which 
delivers clean tap water from a municipal water supply system. Valve arm 
162 is pivotally secured to valve body 156 by pivot axle 164. Valve arm 
162 includes a rubber seal 166 designed to contact and seal against the 
open end of bore 168 extending through valve body 156. Float 170 is 
secured to valve arm 162 by a downwardly depending pin 172 passing through 
float 170. If the level of the water within brine tank 150 drops below the 
level indicated by reference numeral 152, float 170 pivots downwardly and 
permits fresh tap water to enter brine tank 150 until the level of water 
within brine tank 150 again reaches level 152. Thus, as salt initially 
deposited in brine tank 150 is consumed, water is added to brine tank 150 
to occupy the volume previously occupied by the consumed salt. While pool 
water may be used to fill brine tank 150, fresh tap water is preferred 
since fresh tap contains fewer contaminants which could form chlorates or 
hardness deposits within anode chamber 52. 
Referring to FIGS. 11-13, chlorine gas liberated at anode 88 during the 
electrolytic process rises upwardly and is collected by collection baffle 
70 and routed by delivery tube 82 to a mechanism for reacting the chlorine 
gas with pool water. As explained above, pool water circulated through 
power supply housing 34 is delivered by connection tube 42 to an external 
fitting 44. Connector 44 is coupled to an inverted L-shaped tube 174 which 
passes through cylindrical side wall 25 and delivers pool water into a cup 
176 supported within brine tank 150. Cup 176 has an upper lip 178 which 
extends to a height above the water level 152 of brine tank 150. Disposed 
within cup 176 is a smaller inverted cup 180 having a central bore in the 
ceiling thereof in communication with chlorine gas delivery tube 82. As 
shown in FIG. 13, the lower edge of inverted cup 180 has openings 182 
formed therein whereby pool water deposited within cup 176 passes into the 
interior of inverted cup 180. 
A vertically-oriented cylinder 184 extends upwardly from the floor of cup 
176 within inverted cup 180. The open upper end of cylinder 184 terminates 
prior to reaching either the ceiling of cup 180 or upper lip 178 of cup 
176. A plurality of holes, like that designated by reference numeral 186, 
are formed in the floor of cup 176 within the interior of cylinder 184. 
Extending downwardly from the floor of cup 176, and centered with cylinder 
184, is a cylindrical tube 188, the lower end of which is received by an 
annular ring 190 (see FIG. 11) formed upon the upper face of ceiling plate 
58. Cylinder 188 houses a reaction column filled with ceramic burl saddles 
192 which provide a large surface area upon which pool water can absorb 
and react with chlorine gas passing therethrough. Pool water deposited 
within cup 176 passes into the interior of inverted cup 180 and spills 
over the upper lip of cylinder 184 into reaction column 188. Similarly, 
chlorine gas delivered by delivery tube 182 is drawn into reaction column 
188 and intermixes with the pool water falling therethrough to form 
hydrochloric acid and hypochlorous acid. Vacuum breaker tube 183 extends 
upwardly from the upper portion of cathode chamber 130 to a point just 
below the ceiling of inverted cup 180 and maintains atmospheric pressure 
within the upper portion of inverted cup 180. 
Rather than returning the chlorinated pool water formed within reaction 
column 188 directly to the swimming pool, the chlorinated pool water is 
first delivered to cathode chamber 130 at a point remote from primary 
cathode 106. A metering cup of unique design is provided immediately below 
reaction column 188 to add chlorinated pool water at a relatively uniform 
rate (preferably, one-half gallon per minute) to the catholyte in order to 
continuously dilute the catholyte and regulate the hydroxyl ion 
concentration thereof. As shown most clearly in FIGS. 11 and 13, metering 
cup 196 includes a cylindrical side wall 198 having an open upper end 200 
that is secured to the lower face of ceiling plate 58 concentric with 
annular ring 190. Metering cup 196 includes a lower floor 202 which closes 
off the lower end of cylinder 198. A circular opening 204 is formed near 
the lower end of cylinder 198 for metering a flow of chlorinated pool 
water which flows into the catholyte for diluting the same. Floor 202 
includes down-wardly angled portion 206 adjacent hole 204 for allowing 
pool water exiting hole 204 to gently drip into the catholyte from a point 
just above catholyte level 132. 
Assuming that reaction column 188 supplies chlorinated pool water to 
metering cup 196 at a rate faster than that at which water exits through 
hole 204, then a relief must be provided for the excess flow of 
chlorinated pool water. In this regard, a smaller diameter tube 208 
extends upwardly through a bore in floor 202 of metering cup 196. The 
lower end of tube 208 is open and is concentric with the upper open end 
140 of cylinder 136 of the above-described outflow network. The upper end 
of tube 208 is covered by diverter plate 210 so that chlorinated pool 
water dripping into metering cup 196 cannot drip directly into the upper 
end of tube 208. As shown in FIG. 10, the upper end of tube 208 includes a 
notched portion 212 having an upper lip 214 elevated above metering hole 
204. Any chlorinated pool water which accumulates within metering cup 196 
above the level of lip 214 spills over into tube 208 and passes 
therethrough into the overflow network therebelow. Thus, metering cup 196, 
in combination with outflow tube 134 and cross flow tube 144, serve to 
continuously dilute the catholyte within cathode chamber 130 at a 
relatively continuous rate. 
As mentioned above, by allowing the chlorinated pool water produced in 
reaction column 188 to pass through the catholyte before being returned to 
the swimming pool, hydrochloric acid formed in reaction column 188 is 
neutralized by hydroxyl ions within the catholyte in order to render the 
chlorinated pool water that is returned to the swimming pool relatively pH 
neutral. Moreover, the addition of chlorinated pool water containing 
hydrochloric acid rather than pH neutral water, to the catholyte more 
efficiently lowers the hydroxyl ion concentration within the catholyte. 
As mentioned above, one of the objects of the present invention is to 
provide an electrolytic pool chlorinator which maintains a sufficiently 
high hydroxyl concentration near the cathode to permit quick start up and 
good current efficiency while preventing the hydroxyl concentration from 
increasing to the point where significant amounts of back-migration of 
hydroxyl ions occurs. While continuous dilution of the catholyte, in the 
manner explained above, helps prevent excessive hydroxyl ion 
concentration, dilution alone does not insure a sufficient hydroxyl ion 
concentration adjacent the cathode to insure good current conductivity. 
Applicant has determined that a hydroxyl ion concentration adjacent the 
cathode in the range of 1% to 3% is considered optimal for several 
reasons. First, by reducing the hydroxyl ion concentration from 15%-20% 
down to the 1%-3% range, back-migration of hydroxyl ions toward the anode 
can be reduced by approximately 75%. Secondly, a 1%-3% hydroxyl ion 
concentration adjacent the cathode still provides relatively good 
conduction of current between the anode and cathode. Lastly, a 
concentration of 1%-3% of hydroxyl ions in the vicinity of the cathode is 
sufficiently high to cause precipitation of any metal hardness ions before 
such metal hardness ions reach the cathode or the ion permeable membrane. 
As mentioned above, auxiliary cathode 114 serves in part to restrict the 
diffusion of hydroxyl ions away from primary cathode 106, and thereby 
serves to maintain the hydroxyl ion concentration adjacent primary cathode 
106 in the desired range despite the much lower hydroxyl ion concentration 
of the catholyte near metering cup 196 and outflow tube 134. While the 
flow of catholyte is turbulent adjacent the primary cathode 106 due to 
formation of hydrogen gas bubbles, auxiliary cathode 114 damps out such 
turbulence resulting in more viscous flow of the catholyte. In addition, 
any metal hardness ions, such as calcium, which approach toward primary 
cathode 106 tend to precipitate upon the front and rear faces of auxiliary 
cathode 114, thereby reducing by approximately 2/3 the amount of hardness 
deposits which can form upon primary cathode 106. 
To further insure that the hydroxyl ion concentration proximate the primary 
cathode 106 is maintained in the desired 1%-3% range, a baffle network is 
preferably provided within cathode chamber 130 to control the rate at 
which hydroxyl ions generated at the cathode can diffuse toward outflow 
tube 134. The aforementioned baffle network includes an upper baffle 216 
which extends fully across cathode chamber 130 from ceiling plate 58 
downwardly into the catholyte below catholyte level 132. Not only does 
upper baffle 216 serve to control the diffusion of hydroxyl ions, but it 
also forms a gas trap barrier between hydrogen gas which bubbles upwardly 
from cylinder 110 and any unreacted chlorine gas entering the upper 
portion of cathode chamber 130 from reaction column 188 or vacuum breaker 
tube 193. A vent hole 218 is formed in cylindrical side wall 23 on the 
chlorine gas side of upper baffle 216 to prevent dangerous accumulations 
of chlorine gas from forming therein. A lower baffle 220 extends fully 
across cathode chamber 130 generally parallel to and spaced apart from 
upper baffle 216. Lower baffle 220 extends from the floor 24 of cathode 
chamber 130 to an elevation substantially near the lowermost edge of upper 
baffle 216. In the preferred embodiment of the present invention, lower 
baffle 220 extends to a height approximately 1/8 inch below the lowermost 
edge of upper baffle 216, as it has been found that such a relationship 
between the upper and lower baffles helps to maintain the hydroxyl ion 
concentration proximate cathode 106 within the desired range of 1%-3%. 
In order to help insure that metal hardness ions, such as calcium and 
magnesium do not form precipitates within the region of primary cathode 
106 or ion permeable membrane 102, a third baffle 222 is provided. Baffle 
222 extends substantially across cathode chamber 130 parallel to lower 
baffle 220 and spaced apart slightly therefrom. Baffle 222 extends to a 
height above catholyte level 132 and also extends downwardly to a point 
above floor 24 but substantially below the upper edge of lower baffle 220. 
Hydroxyl ions creates at the cathode are permitted to diffuse downwardly 
between lower baffle 220 and baffle 222 for dilution and removal from the 
cathode chamber. Simultaneously, any metal hardness ions tending to 
diffuse upwardly between lower baffle 220 and baffle 222 will encounter a 
significant hydroxyl ion concentration therein and will form precipitates, 
such as Ca(OH).sub.2 and Mg(OH).sub.2, before advancing beyond the upper 
edge of lower baffle 220. Such precipitates are continuously drained out 
from cathode chamber 130 through outflow tube 134. By precipitating metal 
hardness ions in this manner, hardness deposits upon the cathode chamber 
walls and associated plumbing are minimized. 
By forming cathode chamber 130 and anode chamber 52 adjacent the floor 24 
of chlorinator 20, the volume available for storage of salt above ceiling 
plate 58 is maximized. At the same time, however, access to cathode 
chamber 130, as might be required for periodic servicing, is made more 
difficult. In order to permit convenient access to cathode chamber 130 for 
such periodic maintenance, a cathode access pipe 224 extends within 
chlorinator 20 from a point just below removable cover 26 to a point just 
above floor 24, as shown in FIG. 13. Cathode access pipe 224 passes 
through a correspondingly sized bore formed within ceiling plate 58, which 
bore is surrounded by an annular ring 226 (see FIG. 11) that extends 
upwardly from ceiling plate 58. The upper end of cathode access pipe 224 
is surrounded by a larger diameter pipe section 228 serving as a funnel to 
facilitate pouring of fluids into the upper end of pipe 224. 
In order to remove any calcium or magnesium hardness deposits forming 
within cathode chamber 130, the user may periodically flush the catholyte 
with tape water to flush sodium hydroxide from cathode chamber 130. 
Preferably, the lower end of cathode access pipe 224 is disposed on the 
cathode side of upper baffle 216 to more easily flush sodium hydroxide 
from cathode chamber 130. After the aforementioned flushing operation, 
hydrochloric acid can be poured into cathode access pipe 224 for 
dissolving any hardness deposits. Tap water can then be added to cathode 
access pipe 224 for flushing all of the hydrochloric acid out of cathode 
chamber 130. During winter months, a brine solution can be poured into 
cathode access pipe 224 to lower the freezing point of the catholyte and 
thereby avoid damage which would otherwise result were the catholyte to 
freeze on cold winter nights. 
As mentioned above, contaminants, such as calcium and magnesium, within 
anode chamber 52 can combine with hydroxyl ions that back-migrate from the 
catholyte into the anolyte to form chlorates that can reduce the 
concentration of the brine; such contaminates can also form deposits upon 
the anode side of the ion permeable membrane, which deposits can lead to a 
plugging of the membrane and a corresponding reduction in the efficiency 
of the chlorinator. Periodic dilution of the anolyte helps to avoid the 
formation of such chlorates and hardness deposits. Referring to FIG. 13, 
anode access pipe 230 extends upwardly from anode chamber 52, through 
ceiling plate 58 and terminates at an upper end 232 just below the floor 
of cup 176. In order to help support anode access pipe 230, ceiling plate 
58 includes an annular ring 234 extending upwardly from the top face 
thereof for engaging the exterior wall of pipe 230. A further cylindrical 
pipe 236 surrounds the upper end 232 of anode access pipe 230 and extends 
upwardly through the floor of cup 176 to a point just below the upper edge 
178 of cup 176. Float valve 154 (see FIG. 14) maintains the water level 
152 within brine tank 150 approximately 1 inch below the upper end of 
cylinder 236, and approximately 2 inches below upper edge 178 of cup 176. 
The upper end of cylinder 236 is higher than the upper end of cylinder 
184, and accordingly, pool water delivered to cup 176 overflows into the 
reaction column 188, and not into the upper open end of cylinder 236. 
Periodically, the user will note that the level of salt within brine tank 
150 has fallen. This condition can be detected simply by observing the 
height of salt level indicator rod 28. At such time, the user removes 
upper cover 26 and deposits solid salt into brine tank 150 until the salt 
level again reaches level 148. As the user deposits additional salt into 
brine tank 150, the water level within brine tank 150 rises above level 
152. Because the lower end of anode access pipe 230 is open, the water 
level in access pipe 230 and surrounding cylinder 236 into rises until the 
anolyte overflows around the upper edge of cylinder 236 and spills into 
cup 176; in turn, the anolyte overflowing into cup 176 spills over the 
upper end of cylinder 184 and into reaction column 188 for delivery to 
cathode chamber 130. In the above-described manner, contaminants in the 
anolyte are periodically diluted each time salt is added to brine tank 
150. Concentrations of such contaminants within the anolyte are thereby 
prevented from accumulating to harmful levels. 
As described earlier, crossflow pipe 144 extends outwardly from cathode 
chamber 130, terminating in an external chlorinated water delivery port 50 
which supplies chlorinated pool water overflowing from cathode chamber 
130. In some installations, outlet port 50 may be directly connected to a 
gravity feed line back to the swimming pool for returning the chlorinated 
pool water thereto. However, in many installations, such a gravity feed 
line does not exist or cannot be easily added; in such instances, the 
chlorinated water is most easily returned to the swimming pool by coupling 
outlet port 50 to the suction side of the swimming pool pump. Referring to 
FIGS. 8, 9A, 9B, and 13, a feeder tank 240 is shown incorporating a novel 
float valve mechanism for metering chlorinated pool water to the suction 
side of the pool pump without risking a loss of prime which might result 
if air were admitted to the suction side of the pool pump. Feeder tank 240 
includes a circular base 242 and an upwardly extending cylindrical side 
wall 244. A removable cover 246 encloses the upper end of feeder tank 240 
A vent hole 248 is formed in side wall 244 immediately below cover 246. In 
addition, a bore 250 of a size commensurate with the outer diameter of 
crossflow pipe 144 is formed in the upper end of side wall 244 for 
permitting outlet port 50 to extend into the interior of feeder tank 240. 
A rubber retaining ring 260 is inserted over and around outlet port 50 for 
engaging the interior surface of cylindrical side wall 244 to releasably 
retain feeder tank 240 adjacent side wall 23 of chlorinator 20. 
As shown in FIG. 8, base 242 includes a substantially planar upwardly 
facing sealing surface 262 which extends from a first end 264 to an 
opposing second end 266. A flared opening 268 extends down-wardly through 
sealing surface 262, beginning at a relatively narrow and shallow point 
near first end 264 and gradually widening and deepening to a second point 
near second end 266. Flared opening 268 communicates with a bore 270 
extending down-wardly through base 242. Bore 270 is in fluid communication 
with a busing 271 which has an internally threaded bore for threadedly 
engaging one end of an outlet connector 272; the second end of connector 
272 is adapted to be coupled to one end of a water suction line 274, the 
opposite end of which is coupled to the suction side of the swimming pool 
pump. 
Feeder tank 240 also includes a substantially planar, flexible elastomeric 
seal 276 which extends from first end 278 to opposing second end 280. Seal 
276 is preferably made of 40 hardness durometer silicone rubber. As shown 
in FIGS. 9A and 9B, the length of flexible seal 276 is somewhat greater 
than the length of planar sealing surface 262. The first end 278 of seal 
276 is secured to the second end of sealing surface 262 by a pair of pins 
282 and 284 proximate the widest and deepest portion of flared opening 
268. A circular float member 186, made of styrofoam or other buoyant 
material, is secured to the second end 280 of seal 176 by a pair of 
elongated pins 288 and 290. Reinforcing bars 292 and 294 are positioned 
above float 286 and below the second end of seal 280, and fasteners 288 
and 290 extend through reinforcing bar 292, float 286, seal 276, and 
reinforcing bar 294. A pair of ceramic weights 295 and 297 are embedded in 
float 286 to dampen and stabilize the operation thereof. 
Before the pool pump is switched on at the beginning of an operating cycle, 
feeder tank 240 initially contains only a small quantity of water, and 
accordingly, seal 276 rests upon sealing surface 262, sealing off flared 
opening 268, as shown in FIG. 9B. When the pool pump is initially switched 
on, air is prevented from entering into flared opening 268 because it is 
covered over its entire length by seal 276. The vacuum created by the pool 
pump within suction line 274 initially maintains seal 276 tightly against 
sealing surface 262. As pool water begins to circulate through the pump 
and into chlorinator 20, chlorinated pool water will be delivered into 
feeder tank 240 by outlet port 50. The water level within feeder tank 240 
begins to rise, as shown in FIG. 9A, causing float 286 to rise. As float 
286 rises, it lifts second end 280 of seal 276 above sealing surface 262, 
initially exposing only the narrow and shallow end of flared opening 268. 
Ordinarily, it would be difficult to overcome the large amount of suction 
created by the pool pump in order to remove seal 276 from opening 268. 
However, due to the leveraged forces applied by float 286 to seal 276, and 
in view of the gradual enlargement of flared opening 268, seal 276 is 
gradually pealed off of sealing surface 268 to overcome the suctional 
forces created by the pool pump for allowing pool water to flow into 
suction line 274. Moreover, flared opening 268 self regulates the 
operation of the feeder tank 240 by adjusting the outlet flow rate in 
accordance with the amount of chlorinated pool water within feeder tank 
240. The higher float 286 rises, the greater the amount of flared opening 
268 that is exposed, and hence the greater is the rate at which water may 
be withdrawn from feeder tank 240. Such a construction of the feeder tank 
valve permits the float 286 to rise until the inflow of chlorinated water 
into feeder tank 240 balances the outflow therefrom; moreover, the use of 
flared opening 268 allows the described valve structure to be used with 
pool pumps having a wide variation of suction. 
Within FIG. 1, chlorinator 20 is shown in a swimming pool installation 
permitting the return of chlorinated water by gravity feed to the skimmer 
of the swimming pool. Swimming pool 300 includes a skimmer 302 coupled to 
one end of suction line 304, the opposite end of which is coupled to the 
suction side of swimming pool pump 306. The outlet of pump 306 is coupled 
by pressure line 308 to the inlet of filter 310. The outlet of filter 310 
is coupled to a tee connector 312, the central port of which is coupled to 
return line 314 which returns the filtered pool water to swimming pool 
300. An electrical timer or control box 316 is coupled by electrical 
cabling 318 to the electric motor powering pool pump 306. Electrical 
cabling 320 also extends from electrical control box 316 to the power 
supply of chlorinator 20. 
A third port of tee connector 312 is coupled to a further tee connector 
314, one port of which is coupled to a downwardly extending pipe 316, the 
lower end of which extends below the level of the water within swimming 
pool 300 and is closed by a cap 322. Tube 324 extends vertically within 
tube 316 and extends through the upper port of tee connector 314 for 
coupling with pool water inlet port 38 of chlorinator 20 for supplying 
filtered pool water thereto. By extending tube 334 downwardly to the 
bottom end of outer tube 316, water within tube 324 will not be siphoned 
back into the pool when pump 306 is turned off, and the use of a check 
valve may thereby be avoided. 
Outlet 50 of chlorinator 20 is connected by gravity feed line 326 to the 
upper portion of skimmer 302 for allowing chlorinated water overflowing 
from chlorinator 20 to flow back to swimming pool 300 under the force of 
gravity. 
FIG. 2 shows the manner in which chlorinator 20 is installed in conjunction 
with a swimming pool wherein it is not practical to use a gravity feed 
line in order to return chlorinated water to the swimming pool. Those 
components shown within FIG. 2 that correspond with those already 
described above in regard to FIG. 1 are labelled with correspondingly 
primed reference numerals. As in the installation described in FIG. 1, 
skimmer 302' is coupled by suction line 304' to the suction inlet of pool 
pump 306'. However, a tee connector 328 is installed above ground 
immediately ahead of the pool pump suction inlet. A flexible suction tube 
274 extends from the outlet of feeder tank 240 to the upper port of tee 
connector 328 in fluid communication with a reduced diameter tube 330 
which extends downwardly through tee connector 328 and into suction line 
304' to a depth below the level of the water within swimming pool 300'. In 
this manner, no siphoning of water within feeder tank 240 will occur when 
pool pump 306' is turned off. When pump 306' is operating, chlorinated 
pool water is suctioned from feeder tank 240 through suction pipe 274 and 
through downwardly extending pipe 330 into the suction inlet of pump 306'. 
The outlet of filter 310' is coupled by a return line 314' to swimming pool 
300', as described in regard to FIG. 1 above. However, a tee connector 332 
is interposed between filter 310' and return line 314', and water delivery 
tube 324' extends downwardly through tee connector 332 to a depth below 
the level of the water within swimming pool 300'. When pump 306' is 
operating, the positive pressure developed within return the 314' forces 
pool water upwardly through tube 324' for supplying pool water to 
chlorinator 20. By extending tube 324' downwardly within return line 314' 
to a depth below that of the water within swimming pool 300', siphoning of 
water out of delivery tube 324' after pump 306' is switched off is 
prevented, thereby avoiding the need for a check valve. 
It may be recalled that one of the features of the present invention is to 
provide a safety shut-off feature for shutting off electrical power to the 
pool pump motor when pool water fails to circulate through the pool pump 
for an extended period of time despite the application of electrical power 
thereto. Within the preferred embodiment of the present invention, the 
pool pump motor is interconnected with the electrical power supply of 
electrolytic pool chlorinator 20 in a manner best understood with 
reference to FIG. 3. As shown in FIG. 3, a 240 volt alternating current 
voltage is supplied by conductors 350, 352 and 354, conductors 350 and 352 
representing the "hot" lines, while conductor 354 represents a ground 
connection. A ganged switch 356, which may be operated manually or by an 
electrical timer 358, simultaneously connects or disconnects hot lines 350 
and 352 to terminals 360 and 362, respectively. Conductor 350 is coupled 
to a first terminal 364 of a field wiring block 366 disposed within power 
supply housing 34 of chlorinator 20. Conductor 362 is coupled to a second 
wiring terminal 368 of field wiring block 366. Ground conductor 354 is 
electrically connected with ground screw 370, visible upon the front face 
36 of power supply housing 34 (see FIG. 4). Chlorinator 20 is also 
provided with a chassis ground connection screw 372 adapted to be coupled 
to a wire in physical contact with the earth. 
As shown in FIG. 3, pool pump motor 374 is coupled to ground line 354 and 
includes a first A.C. voltage terminal coupled to terminal 360 for 
receiving an alternating current voltage therefrom. The second hot 
terminal of pool pump motor 374 is coupled to terminal 376 of field wiring 
block 366, rather than being directly coupled to terminal 362, as is the 
usual case. 
Within electrical power supply housing 34 of chlorinator 20 is a resistive 
heater 380 which, in the preferred embodiment, is a 3K ohm 25 watt heating 
element, coupled in series with a time-delayed slow-blow fuse 382 between 
field wiring block terminals 364 and 368. Fuse 382 is rated at 11/2 amps 
at 250 volts. Referring to FIG. 62, resistive heater 380 is secured to a 
metal bar 384 which is in thermal contact with metal conduit 46 through 
which pool water is ordinarily circulated. Resistive heater 380 generates 
heat which is absorbed by metal bar 384 and which is ordinarily dissipated 
into the pool water flowing through metal conduit 46. 
As shown in FIG. 3, a thermostatic switch 386 is coupled between field 
wiring block terminal 368 and electrical terminal 388. Thermostatic switch 
386 may be of the type commercially available from Therm-O-Disc, a 
division of Emerson Electric of Mansfield, Ohio. Referring to FIG. 6, 
thermostatic switch 386 is also coupled to metal bar 384 in thermal 
contact therewith. Thermostatic which 386 is designed to normally remain 
closed when the temperature thereof is below a predetermined safe 
temperature. If pool water stops flowing through metal conduit 46 while 
electrical power continues to be supplied to field wiring block 366, then 
after approximately five minutes, the temperature of metal bar 384 and 
thermostatic switch 386 rises above the aforementioned predetermined 
temperature, and themostatic switch 386 opens. Applicant's prior U.S. Pat. 
No. 4,599,159 discloses a similar arrangement of a thermostatic switch and 
resistive heater. 
Still referring to FIG. 3, the junction of resistive heater 380 and fuse 
382 is coupled to the central contact 390 of a rotary switch 392 having an 
inactive contact 394 for allowing the chlorinator to be turned off 
manually. Rotary switch 392 also includes peripheral contacts 396, 398, 
400, and 402, which permit the rate at which chlorine is produced by 
electrolytic chlorinator 20 to be varied, as explained below. Rotary 
switch 392 is visible in FIGS. 5 and 6 upon the rear panel 404 of 
chlorinator 20. 
As shown in FIG. 3, the chlorinator power supply includes a transformer 406 
having a primary coil 408 with a number of input tap points along the 
length thereof. Each of the plurality of input tap points is coupled to 
one of the peripheral contacts 396-402 of rotary switch 392, whereby the 
number of coil turns supplied with the 240 volt alternating current source 
voltage can be varied, thereby varying the output alternating current 
voltage produced across secondary coil 410. The opposing end of primary 
coil 408 is coupled through a time-delayed, slow-blow fuse 412 back to 
electrical terminal 388, in order to complete the flow of current through 
thermostatic switch 386. Fuse 412 is rated at 11/2 amps at 250 volts. 
As shown in FIG. 3, secondary coil 410 of transformer 406 includes a center 
tap 414 coupled through electrical meter 416 to conductor 124 for applying 
a negative DC potential to primary cathode 106 (and optionally to 
auxiliary cathode 114). The ends of secondary coil 410 are coupled by 
rectifying diodes 418 and 420 which are joined at node 422. Conductor 90 
couples node 422 to anode 88 for applying a positive direct current 
potential thereto. Electric meter 416, which is visible upon rear panel 
404 within FIGS. 5 and 6, indicates the averaged DC current flowing 
between anode 88 and cathode 106, thereby providing an indication of the 
rate at which chlorine gas is being produced by chlorinator 20. In the 
preferred embodiment of the present invention, the chlorinator is operated 
in the voltage range of 3-6 Volts D.C., and in the current range of 4-30 
Amps. 
Referring again to FIG. 3, electrical terminal 388 is coupled by conductor 
424 to terminal 376 of field wiring block 366. Accordingly, when 
thermostatic switch 386 is in its usual closed position, the alternating 
current voltage sourced by conductor 352 is coupled through terminal 368, 
through thermostatic switch 386, and through terminal 376 to the second 
hot input terminal of pool pump motor 374, thereby providing 240 Volt A.C 
electrical power thereto. However, if thermostatic switch 386 opens, as 
when pool water has stopped flowing through metal conduit 46 of 
chlorinator 20 for more than five minutes, then the alternating current 
voltage sourced by conductor 352 is no longer applied to pool pump motor 
374, thereby avoiding damage to the pool pump motor which might otherwise 
result when the pool pump loses its prime or is otherwise deprived of pool 
water at its suction inlet. 
It should now be appreciated by those skilled in the art that an 
electrolytic pool chlorinator for chlorinating a swimming pool or the like 
has been described which provides many unique advantages in comparison 
with known electrolytic chlorinators and which fully meets all of the 
above-stated objects of the present invention. While the invention has 
been described with reference to a preferred embodiment thereof, the 
description is for illustrative purposes only and is not to be construed 
as limiting the scope of the invention. Various modifications and changes 
may be made by those skilled in the art without departing from the true 
spirit and scope of the invention as defined by the appended claims.