Pool chlorinator

There is disclosed a device for dispensing a chemical wherein a stack of dry chemical tablets are contained within a receptacle. Sealing means are provided to seal around each tablet and the inner wall of the canister so that only the upper surface of the top tablet is exposed to the circulating water. The tablets are not exposed to the flowing water until the tablets above have been eroded away successively to provide leak paths around them.

BACKGROUND OF THE INVENTION 
A system commonly employed for introducing chemicals into a circulating 
water of a pool or a spa involves the provision of a container for 
compressed tablets of the chemical in dry form through which circulating 
water is diverted to erode the tablets and carry the chemical down the 
line in solution. One problem encountered in such chemical dispensers or 
chlorinators is that, while the chemical content of the water tends to be 
rather high when the container is first loaded and more tablets are 
exposed to erosion by the flowing water, the chemical content falls off as 
fewer and fewer tablets are so exposed. 
OBJECTS OF THE INVENTION 
It is an object of this invention to provide a chemical dispenser for a 
pool wherein chemicals in tablet form are eroded and dissolved more slowly 
and for a more extended period of time. 
It is a further object of this invention to provide a pool chlorinator 
wherein chlorine in tablet form is entered into solution at a controlled 
rate. 
Further objects and advantages of this invention will become apparent from 
the description to follow, particularly when read in conjunction with the 
accompanying drawing. 
SUMMARY OF THE INVENTION 
In carrying out this invention, we provide a receptacle or canister wherein 
a plurality of chemical tablets, e.g. dry chlorine, are stacked. A supply 
of water is drawn from the pool circulating system, and diverted to enter 
the canister and flow over the top of the stacked tablets. The water, with 
some of the chemical in solution, then flows back up to exit and flow down 
the line. Seal means are provided around the tablets to seal between each 
tablet and the inner wall of the canister so that only the top tablet is 
exposed to the water until it has been eroded to the extent that a flow 
path is eroded around the top tablet to expose the top of the next tablet.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring now to the drawing with greater particularity, the pool 
chlorinator 10 of this invention comprises a cap portion 12 having aligned 
flow passageways 14 and 16 for connection into the circulation line (not 
shown) of a swimming pool or spa. Within the cap, the flow passageways 
taper down in diameter at 18 to form a venturi throat 20 wherein there is 
a low pressure zone. 
Secured to the cap 12 as by threading at 22 is a canister or receptacle 24 
of a size to receive a stack of open top cups 26 (FIG. 2). The cannister 
24 is sealed off by an O-ring 28 to render it watertight. 
Water is drawn off from the inlet flow passageway 18 and delivered to the 
receptacle 24 through an inlet scoop 30, and then is drawn from the 
receptacle 24 through the outlet port 32 to the low pressure zone 20, from 
which it is carried to the downstream passageway 16. As the water 
circulates through the canister it contacts, erodes and dissolves a 
quantity of chlorine to carry it downstream with the water in the flow 
passageway. 
In the embodiment shown, each cup 26 contains a chlorine tablet C. Each cup 
has an outer, inclined lip 34 or flange that engages and seals around the 
cylindrical receptacle 24, whereby water is prevented from circulating 
around the stacked cups. A bead 36 around the bottom of each cup 26 is 
nested into a complementary annular recess 38 around the upper end of the 
next lower cup. An opening 40 in the bottom of each cup permits flow of 
water from one cup to the next, but such flow is initially prevented by 
sealing engagement of a capsule with an annular sealing lip 42 around the 
opening 40. 
In operation, a stack of cups 26, each with a chlorine tablet C, is placed 
within the receptacle 24 and the receptacle is secured to the cap 12. 
Then, with water circulating in the flow line 14, 16, the inlet duct 30, 
facing into the flowing stream, draws off a quantity of water to circulate 
down over the top of the uppermost tablet C. With the sealing flanges 34 
engaging the wall of the canister, and with each tablet sealed on the 
annular sealed lip 42, the flow of water is restricted to the top tablet C 
until there has been sufficient erosion to create a leak path past the 
tablet and through the central opening 40 to contact the next tablet. 
Hence, erosion of the tablets is greatly retarded, and there is a more 
even distribution of chemical into the downstream flow. 
While this invention has been described in conjunction with a preferred 
embodiment thereof, it is obvious that modifications and changes therein 
may be made by those skilled in the art to which it pertains without 
departing from the spirit and scope of this invention, as defined by the 
claims appended hereto.