Water purifer for a pool

The invention features a water purifier for purifying water in a pool having a volume less than about 13,500 gallons. In general, the water purifier has a threaded fitting that allows it to be removably-attached to a water-exchange fitting, preferably on the side of the pool. The water purifier contains a purification material for purifying the water. The purification material preferably can be a silver-containing material.

BACKGROUND OF THE INVENTION 
The invention relates to water purifiers. 
It is important to have a reliable method for purifying water in swimming 
pools. In many situations, water is purified to remove micro-organisms, 
such as bacteria or algae, and harmful metal ions, such as mercury, lead 
and copper. Purification of pool water can be accomplished by filtration 
and by adding chemicals like chlorine, bromine, or silver ions to the 
water. 
One type of above-ground pool, commonly known as a "splash pool," is 
relatively inexpensive and typically has a volume of less than about 7,500 
gallons. A splash pool usually has a low horsepower pump, e.g., between 
1/25 and 1/2 horsepower, for recirculating water in the pool. The pool 
water can be filtered and is ordinarily purified by adding chlorine. 
SUMMARY OF THE INVENTION 
The present invention features a water purifier for purifying water in a 
pool having a volume less than about 13,500 gallons. In general, the water 
purifier has a threaded fitting that allows it to be removably-attached to 
a water-exchange fitting, preferably on the side of the pool. The threaded 
fitting on the water purifier preferably is male-threaded and the 
water-exchange fitting preferably is female-threaded. The water purifier 
contains a purification material for purifying the water. The purification 
material-preferably can be a silver-containing ceramic material. 
The water purifier preferably includes a housing having a chamber for 
containing the purification material. The housing also includes a water 
inlet and a water outlet. The housing preferably has a height of less than 
6 inches, and, more preferably, less than 3 inches. The chamber preferably 
has an internal volume of at least 30 cubic centimeters, preferably 
between 30 and 100 cubic centimeters, and more preferably between 40 and 
80 cubic centimeters. 
The water purifier preferably has an exposed surface having rounded edges. 
The water purifier preferably is circular and has a diameter of between 3 
and 12 inches, most preferably about 41/2 inches. The height of the water 
purifier can be less than 6 inches, and is preferably less than 3 inches. 
Most preferably, the height is about 11/4 inches. 
The water purifier can provide one or more of the following advantages. 
Since the water purifier can be removably-attached to a water-exchange 
fitting that is part of the circulation system of the pool, the water 
purifier can be used without modification of the plumbing system of the 
pool. In addition, when the purification material is silver-containing 
material, the water can be effectively purified using oxidizing agents 
other than chlorine alone (e.g., potassium peroxymonosulfate). 
Further, when the purification material is a monolithic ceramic foam with 
large pore sizes or is formed as large pieces that cannot fall through 
openings in the water exit of the purifier. Generally, the ceramic foam 
has between 10 and 45 pores per inch, preferably between 10 and 25 pores 
per inch. The large pieces of purification material are generally between 
1 and 30 mesh in size, preferably between 5 and 15 mesh, and most 
preferably between 7 and 14 mesh. When the water purifier includes a door, 
the purification material can be exchanged easily without replacing the 
entire water purifier. Since the purification material preferably has a 
large pore size or is formed of relatively large particles, the preferred 
water purifier exerts little or no back-pressure on the filter as water is 
circulated. 
The water purifier is suitable for purifying water in small swimming pools, 
particularly above-ground pools with volumes less than about 13,500 
gallons. It is particularly suitable for use in splash pools. It is 
preferred that the water purifier receive filtered water. 
The term "circulated," as used herein, means continuous flow of the water 
to expose the water to the water purifier, for example, as it is pumped 
through a filter. 
Other advantages and features of the invention will be apparent from the 
description of the preferred embodiment, and from the claims.

DETAILED DESCRIPTION 
Referring to FIG. 1, splash pool 2 has a bottom 3 and wall 4 which define 
the volume of the small above-ground pool. The volume of splash pool 2 is 
less than 7,500 gallons. Water is circulated in splash pool 2 by pump 6, 
which is attached to the side of the pool by conduit 8. Water is 
circulated by a pump from an intake fitting to the discharge fitting 
through conduit 8. The water can be filtered during circulation. Water 
purifier 10 receives water that is pumped by pump 6. 
Referring to FIGS. 2 and 3, water purifier 10 has a chamber 12, located 
inside circular housing 13, for containing a purification material (not 
shown) that kills bacteria in water. Chamber 12 has an internal volume of 
50 cubic centimeters. Water purifier 10 has a water inlet 14 that permits 
water to enter chamber 12, and a water outlet 16 that permits water to 
exit the chamber. Water outlet 16 has openings 40. 
The circular housing 13 has a diameter (D) of 41/2 inches. The housing 13 
has a height (H) of about 11/4 inches. Water purifier 10 generally can be 
made of a plastic or other suitable material, like PVC, polyethylene, 
polypropylene, or other moldable plastics. 
Referring to FIG. 4, water purifier 10 is removably-connected to 
female-threaded water-exchange fitting 22 through male-threaded fitting 
20. Water-exchange fitting 22 extends through pool wall 4. When water 
purifier 10 is connected to fitting 22, a surface of water purifier 10 is 
substantially contiguous (i.e. adjacent) to pool wall 4 (see, e.g., FIGS. 
1 and 4). 
Referring to FIGS. 5-7, an alternate water purifier has a top 30 and a 
bottom 32 which serves as an access through which the purification 
material can be added, removed, or replaced. Top 30 has a space that 
serves as chamber 12. Bottom 32 includes water inlet 14 that has 
male-threaded fitting 20 that screws into the female-threaded 
water-exchange fitting 22 of the pool. 
The preferred purification materials are described, for example, in U.S. 
Pat. No. 5,352,369 and in U.S. Ser. No. 08/628,405, entitled 
"Self-Regulating Water Purification Composition" and filed Apr. 5, 1996, 
which are incorporated herein by reference. Examples of these purification 
materials include silver metal on a support. The support can be a ceramic 
and can include an inorganic oxide, e.g., an aluminum oxide. The silver 
can be chemically deposited on the ceramic support or dispersed as a 
powder, shavings, or turnings with the ceramic support. The preferred 
silver content of the purification material is between 0.1 and 10 weight 
percent. The purification material can include a second metal, preferably 
zinc, copper, aluminum, iron, or manganese, most preferably, zinc. 
The purification material is preferably formed into particles larger than 
the individual openings 40 in the water purifier, e.g., as pellets or as a 
monolithic foam, so that the material is adequately contained in chamber 
12. Alternatively, the purification material can be contained in a porous 
container, for example, a mesh bag. 
It is preferred that the purification material be used in the presence of 
oxidizing agents dissolved in the water, such as, for example, ozone, 
potassium peroxymonosulfate, or chlorine. 
In addition to acting as an anti-microbial agent, the purification material 
can effectively remove metal ions, such as mercury, lead, cadmium, iron, 
manganese, copper, nickel, chromium, barium, and arsenate, particularly 
when the purification material includes silver, an inorganic oxide such as 
alumina, and zinc. When zinc is included in the purification material, 
zinc ions can be released into the water which enhance disinfection of the 
water and provide algaestatic properties. 
Other embodiments are within the claims.