U.S. patent number 3,867,290 [Application Number 05/366,984] was granted by the patent office on 1975-02-18 for apparatus for chemical treatment of swimming pools.
Invention is credited to Charles A. Mackey.
United States Patent |
3,867,290 |
Mackey |
February 18, 1975 |
Apparatus for chemical treatment of swimming pools
Abstract
A swimming pool having an automatically timed pump and filter
system has a precisely determined amount of liquid chlorine
injected into its water at the cyclical rate of pump operation. A
chlorine dispensing chamber is entirely immersed in a supply of
chlorine and includes a flexible diaphragm dividing the chamber
into feed and drive compartments. The feed compartment is connected
by means of an inlet conduit fitting and check valve to the
chlorine supply and also by means of an outlet fitting conduit and
check valve to a point in the recirculating system downstream of
the filter. The drive compartment is connected solely to the high
pressure side of the pump so that pressure in the drive compartment
when the pump is operating will move the flexible diaphragm to
decrease the volume of the feed compartment and expel the chlorine
into the swimming pool. When the pump stops operating, water in the
drive compartment returns to the pool, and a weight on the
diaphragm returns it to its initial position, concomitantly
refilling the feed compartment from the supply.
Inventors: |
Mackey; Charles A. (Buena Park,
CA) |
Family
ID: |
23445461 |
Appl.
No.: |
05/366,984 |
Filed: |
June 4, 1973 |
Current U.S.
Class: |
210/138;
210/167.11; 210/206; 210/199 |
Current CPC
Class: |
E04H
4/12 (20130101); C02F 1/76 (20130101); C02F
1/686 (20130101); C02F 2209/44 (20130101); C02F
1/008 (20130101); C02F 2103/42 (20130101) |
Current International
Class: |
C02F
1/76 (20060101); C02F 1/68 (20060101); E04H
4/00 (20060101); E04H 4/12 (20060101); C02F
1/00 (20060101); E04h 003/16 (); B01d 035/00 () |
Field of
Search: |
;137/101.11,564.5
;210/62,138,139,169,198R,199,206 ;417/394,395 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hart; Charles N.
Assistant Examiner: Spitzer; Robert H.
Attorney, Agent or Firm: Gausewitz, Carr &
Rothenberg
Claims
1. In combination with a swimming pool having water recirculating
means including a first intermittently operable pump for
recirculating the water of the pool, a positive displacement pump
for dispensing a metered amount of chlorine in response to
operation of said first pump comprising
a chamber adapted to be filled with chlorine,
piston means mounted within the chamber and movable between first
and second positions,
means responsive to said first pump for driving said piston means
to said first position when said first pump is in operation and for
driving said piston means to said second position when said first
pump is not in operation,
means for filling said chamber with chlorine as said piston means
moves to said second position, and
means for flowing chlorine from said chamber to said swimming pool
as said
2. The chlorine dispenser of claim 1 wherein said piston means
comprises a flexible diaphragm separating said chamber into drive
and feed compartments, wherein said means reponsive to said pump
comprises a conduit interconnecting a first one of said
compartments to a first point of said recirculating means and a
second conduit connecting the other of said compartments to a
second point of said recirculating means having a
3. The apparatus of claim 2 wherein said means for driving said
piston means to said second position comprises a weight secured to
said flexible diaphragm and operable to move the diaphragm to said
second position when said first pump is not operating and the
pressure in said drive
4. The apparatus of claim 2 wherein said drive compartment has
communication only with said first point of said recirculating
means, whereby water in said drive compartment is returned to said
recirculating
5. The apparatus of claim 3 wherein said flexible diaphragm
includes a continuous flange depending therefrom into said first
compartment and wherein said weight comprises a solid body
resiliently retained within said flange, said flange and solid body
having inter-engaging locking bead
6. The apparatus of claim 2 wherein said means for filling said
chamber comprises a container confining a body of chlorine, said
dispenser being immersed in said body of chlorine and having a fill
conduit with an input
7. Water treatment apparatus comprising a positive displacement
pump for dispensing a metered amount of a treatment chemical in
response to operation of a recirculating pump, said positive
displacement pump comprising
a sealed housing defining a chamber therein,
a flexible diaphragm separating the chamber into drive and feed
compartments, said diaphragm extending substantially horizontally
across said chamber and said chamber having a horizontal dimension
considerably greater than its vertical dimension, whereby said
diaphragm may be displaced through a relatively small distance to
effect a relatively large change in the volume of said feed
compartment,
a recirculating water system including a water treatment device
having an input line and an output line, said water system
including an intermittently operating recirculating pump,
a first conduit connecting said drive compartment to the input line
of said treatment device,
a second conduit connecting said feed compartment to the output
line of said treatment device, and
a third conduit connecting said feed compartment to a supply of
liquid
8. The apparatus of claim 7 including a continuous flexible flange
secured to and depending from said diaphragm into said drive
compartment, and a
9. The apparatus of claim 7 including a container, liquid chlorine
confined within said container, said housing being immersed within
the chlorine in the container and said third conduit connecting
said feed compartment to
10. For use with a swimming pool water recirculation system having
a first pump, a positive displacement pump for dispensing a metered
amount of chlorine in response to operation of said first pump,
said positive displacement pump comprising a relatively flattened
housing defining a chamber having a horizontal extent substantially
greater than its vertical extent,
a flexible diaphragm extending across said chamber and having its
periphery continuously fixed and sealed to the chamber and dividing
the chamber into drive and feed compartments,
adjustable means for limiting displacement of said flexible
diaphragm,
a common inlet and outlet conduit fitting connected with said drive
compartment,
an outlet conduit fitting connected with said feed compartment, and
having a check valve therein,
a supply conduit fitting connected with said feed compartment and
having a check valve therein,
a container adapted to receive a quantity of liquid chlorine, said
housing being positioned within and substantially at the bottom of
the container and immersed within chlorine confined within the
container, said supply fitting having an input port adjacent the
top of said housing whereby a decreased height of chlorine in the
container will cover said input port,
said diaphragm having a flange secured thereto, a weight secured to
said flange, said weight comprising a solid body having a
substantially continuous peripheral groove, said flange comprising
a closed depending wall formed with an integral bead that mates
with and is received within the groove of said solid body to firmly
and resiliently secure the solid
11. In combination with a swimming pool having a first pump and
filter for recirculating and filtering the water thereof and a
timer for cyclically turning the pump on and off to cyclically
provide recirculating pressure and provide the absence of
recirculating pressure, a positive displacement pump responsive to
operation of said first pump for feeding a fixed quantity of liquid
water treatment chemical to the pool repetitively at the cyclical
rate at which the first pump is turned on and off by the timer,
said displacement pump comprising
a compartment having a wall movable between a first position in
which said compartment has a relatively large volume of fixed
magnitude and a second position in which said compartment has a
relatively small volume,
an outlet conduit connecting the compartment to said swimming
pool,
a supply of liquid treatment chemical connected with said
compartment,
means for urging said movable wall to said first position, and
means responsive to said recirculating pressure for countering said
urging means to drive said movable wall to said second position,
whereby a fixed quantity of liquid chemical is expelled from said
compartment into said pool when the first pump is turned on and
whereby the compartment is refilled with the liquid chemical from
said supply when the first pump is
12. The combination of claim 11 including means for selectively
varying one of said positions of said movable wall so as to
selectively adjust the difference between said relatively large and
small volumes.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to chemical treatment of closed
recirculating liquid systems, and more particularly relates to an
automatic precision chlorine dispenser for swimming pools.
2. Description of Prior Art
Liquids of varying types are mixed with each other in many
different types of situations, in many applications and for a wide
variety of purposes. Among the many liquid treatment applications,
the bacteriocidal treatment of closed recirculating aqueous
systems, and, in particular, the chlorination of swimming pools,
are common. In most of such treatment systems, a number of criteria
must be fulfilled. Chemicals must be added to the main liquid
system in precise amounts. The apparatus must be reliable and long
lasting in the presence of corrosive materials and environments. It
must present few hazards. It should be self-operating or
semi-automatic, requiring a minimum of service and yet be simple
and inexpensive to manufacture and maintain.
Automatic swimming pool chlorination systems presently on the
market employ chlorine in powder or solid form which is mixed with
water of the swimming pool in a separate compartment to provide a
highly chlorinated slurry that is then continuously mixed with the
swimming pool water as the water is recirculated. These devices
include sensitive float operated valves that are readily jammed in
either open or closed position by minute particles or debris that
are often found in swimming pool water. Should the input valve to
the chlorinating slurry chamber become stuck in closed position,
the chamber can be emptied of its slurry, thereby pulling air into
the pump and causing serious damage to this device.
Another disadvantage of these systems is that they require the
handling of the solid or powdered chlorine, thus, creating hazards
due to the fumes spreading in and about the chlorine dispenser.
Further, chlorine in solid or powder form is more expensive than in
liquid form.
The prior art devices feed the chlorinated slurry in amounts
dependent upon the pressure in the pool recirculating system. As is
well known, in the course of the filtering of the water, the filter
provides increasing restriction to the recirculating flow whereby
the recirculating pressure and quantities of recirculating water
decrease. Therefore, as the conventional filter of the swimming
pool becomes dirty, the amount of chlorination provided decreases
in these prior systems.
Other types of solid chlorinating systems include various devices
for feed pre-selected quantities of powdered chlorine into the
recirculating pool water. None of these devices provide precision
metering since the actual amount of chlorine added, whether in
solid form or in powdered form, is not precisely controllable and
further, adjustment of the chlorination rate is not readily
controlled. In many of the prior devices, the treatment chemical
input, in the form of water having excessively high concentration
of chlorine, is passed through much of the recirculation equipment
(e.g. through the pump filter and heater) before it is mixed with
the main body of pool water. Thus, these relatively expensive
devices are subjected to the exceedingly harsh environment and
adverse effects of the high chlorine concentration.
Other fluid proportioning systems such as those shown in U.S. Pat.
No. 549,479 to Hall and U.S. Pat. No. 2,618,510 to Mills, employ
liquid expulsion chambers, but these are not automatically
cyclicable, require complex valving systems, waste the drive water,
or are not otherwise applicable to closed recirculating swimming
pool systems.
Accordingly, it is an object of the present invention to provide a
swimming pool chlorination method and apparatus that is effective,
simple and reliable and yet, avoids or minimizes most of the
defects of present systems.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention in accordance
with a preferred embodiment thereof, a liquid treatment chemical is
added to a recirculating system at a fixed rate and in amounts
substantially independent of pressure variation of the
recirculating system by employing the pressure of the recirculating
system to empty into the body of the system, the contents of a
chamber that is substantially completely filled with the treatment
liquid. This step is repeated each time recirculation starts, and
each time the recirculation stops, the substantially emptied
chamber is once again filled with the liquid treatment chemical. In
a specific embodiment, a liquid treatment chemical feed compartment
is substantially emptied by a movable wall that operates in
response to recirculating pressure to drive the liquid chemical
treatment from the feed compartment. Means are provided to return
the movable wall to a refilling position when the pressure of
recirculation diminishes or ceases to thereby refill the feed
compartment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a swimming pool and recirculation
system therefor showing the connection of a chlorine dispenser
constructed in accordance with princples of the present invention,
and
FIGS. 2 and 3 show details of the chlorine dispenser of FIG. 1.
DETAILED DESCRIPTION
Referring now to FIG. 1, a tank such as a conventional swimming
pool 10 is provided with a recirculation, filtering and heating
system comprising a pump 12, filter unit 14 and heater 16,
connected in a conventional manner to provide for filtering and
heating of the water of the swimming pool as it is recirculated.
Recirculating water may bypass the heater if deemed necessary or
desirable by means of conventionally arranged flow lines and valves
(not shown). Also conventional is a timer 18 that is set to
automatically turn pump 12 on and off at preset times during each
day of pool operation. Preferably, the timer is set to turn the
pump on and off at least one time each day and, preferably, at the
same times during each day. For other operations, the timer may be
set to turn the pump on and off two or three times each day, but in
general, always at the same time. Thus, the pump may be turned on
at 9:00 a.m., 12:00 noon and 3:00 p.m. each day and turned off at
11:00 a.m., 2:00 p.m. and 5:00 p.m. each day. As another example,
the pump may be turned on each 9:00 a.m. and turned off each 8:00
p.m. Obviously, the timing of the pump cycles is widely variable,
the pump may even be caused to be inoperable on alternate days, and
may be selected as deemed necessary or desirable. Nevertheless, it
is preferred for the practice of the invention that the timer be
set to provide at least one complete cycle of pump operation each
day, one complete cycle being the turning on of the pump and
thereafter the turning off of the pump, until the time of the next
turn on.
In accordance with the present invention, means are provided that
are automatically operable in response to the regular automatically
timed cycling of the recirculation system to dispense fixed amounts
of a liquid treatment chemical, such as liquid chlorine, into the
pool at fixed intervals. The arrangement is such that the overall
rate of addition of the liquid treatment chemical is precisely
fixed and is fully and completely independent of pressure of the
recirculation system. Accordingly, whether the filter is clogged
with dirt or in its condition of maximum flow, the pressure
operated chlorination of the present invention will continue to
provide a precise metering of a substantially fixed quantity of the
liquid dispensed. Since an exactly predetermined quantity of liquid
chlorine is dispensed upon each cycle of pump operation, and since
the number of cyles of pump operation per day (e.g. the cyclical
rate) is the same each day, the overall rate of the chlorination is
both precisely determined and substantially invariable, unless
adjusted as described below.
The apparatus for dispensing the liquid treatment chemical namely,
liquid chlorine, in accordance with a preferred embodiment of the
invention, is shown in FIG. 1 to comprise a positive displacement
pump having a dispensing chamber 20 positioned at the bottom of a
container 22 that is substantially filled with a liquid treatment
chemical 24. Chamber 20 has an input and output pressure conduit
fitting 26 connected via a conduit 28 to a fitting 30 formed on a
removable cover 32 of the container 22. Fitting 30 is connected via
a conduit 34 and gate valve 36 to the output pressure line 38 of
pump 12 at a point between the pump and the input to filter 14.
Chamber 20 is also provided with an output pressure fitting 40 that
is connected by a conduit 42 to a fitting 44 on container cover 32.
Fitting 44 is connected via a conduit 46 and gate valve 48 to the
recirculating system at a relatively low pressure point thereof, in
particular, at a point downstream of the pool operating equipment
including the pump, filter and heater. This is illustrated as point
50 in FIG. 1. The several fittings are readily disconnectable, at
least at the cover 32.
Chamber 20 has a third fitting in the form of an inlet or supply
port 52 of a relatively short extent, so that this supply fitting
may continue to be immersed in the body 24 of the liquid treatment
chemical supply even when the level in container 22 is lowered. For
similar reasons, the chamber 20 is formed of a flattened
configuration, having a greater horizontal dimension than vertical
dimension. It may be noted at this point, as will be described more
particularly below, that the particular flattened configuration of
chamber 20 has the additional advantage of allowing for a greater
displacement of volume of the feed compartment of dispensing
chamber 20 upon a shorter distance of travel of the movable wall
thereof.
As shown in greater detail in FIGS. 2 and 3, chamber 20 is made of
two mating molded plastic bodies collectively providing a
configuration substantially similar to an oblate spheroid. A first
half 54 is threadedly engaged and connected with a second half 55
of the chamber 20 and the interior is separated into two
compartments by a flexible diaphragm 56. Diaphragm 56 extends
completely across the large dimension of the chamber and is formed
with an integral bead or O-ring 58, that is secured to and between
the mating halves 54, 55 of the chamber 20. Thus, the chamber is
separated into two sealed compartments, an upper or feed
compartment 60 and a lower or drive compartment 62. Although it is
convenient to form the two halves of the chamber 20 in the
illustrated mating threadedly secured arrangement, it will be
readily appreciated that the two parts may be secured to each other
in any other fashion as by the welding or heat sealing of plastic
flanges or the like. Further, the chamber need not be made in
substantially similar parts but can be made with a sealing top or
cover plate or other arrangement that will provide access to the
interior for the mounting and securement of the dividing and
separating flexible membrane prior to sealing of the chamber and
the two compartments thereof.
Membrane 56 has secured to the midpoint of a bottom portion thereof
a massive body such as a lead weight 64. Although the weight 64 may
be secured to the membrane in many different fashions as will be
readily apparent to those skilled in the art, a preferred
arrangement is shown in detail in FIG. 3. As illustrated in this
Figure, the central portion of the membrane is provided with a
reinforcing layer 66 of limited extent. A continuous closed
depending circular flange or lip 68 projects downwardly from the
membrane into the drive chamber 62. Flange 68 is formed with a
continuous circular bead 70 on the depending outer edge thereof.
Lead weight 64 is formed with an exterior periphery that mates with
the interior periphery of the circular flange 68 but having a
somewhat larger diameter. The weight has a continuous peripheral
groove 72 that mates with and receives the bead 70 of the depending
circular flange 68. The circular flange is resiliently stretched to
receive the lead weight so that the latter is securely and firmly
affixed to the flexible diaphragm by the resilience of the
depending flange and the interengagement of the bead 70 and groove
72.
Pressure inlet and outlet fitting 26 of the chamber 20 is in fluid
communication with a conduit 74 that is formed in the lower half 55
of the chamber. Conduit 74 is in fluid communication with the drive
chamber 62.
Supply inlet fitting 52 is integrally formed in the upper half 54
of the chamber 20 and includes a silicon rubber check valve 80 that
is held in place by a valve stop 82 secured to the inlet fitting
52. The check valve allows chlorine to flow into compartment 60 but
prevents flow from the compartment through this one-way valve.
Outlet fitting 40 comprises a valve body 84 threaded in an integral
boss 86 of the upper half 54 of housing 20. Mounted in the valve
body 84 is a valve poppet 88 that is urged against the valve seat
of valve body 84 by means of a spring 90 that is held in place by a
valve adjusting retainer 92. Retainer 92 is adjustably and
threadedly received within the bore of the valve body 84. Valve
body 84 is formed with a lower valve adjustment or abuttment
surface 94 that provides an adjustment stop for the chlorine
dispenser. Valve body 84 is provided with adjustment handles 96 and
valve retainer 92 is provided with an adjustment handle 98 whereby
each of these members may be threadedly engaged with and moved
axially with respect to its threaded mate.
Because of the use of the described apparatus in the corrosive
environment of liquid chlorine, all the parts described above are
preferably made of material resistive to such environment. Flexible
diaphragm 50 is preferably formed of a silicon rubber and may be of
a thickness in the order of 0.040 inches. Preferably, all of the
parts including the housing providing the chamber halves 54, 56,
the various valve parts and valve seats are also made of silicon
rubber, excepting only the lead weight (which may be about
one-fourth to one-half pound) and the valve springs.
In an exemplary arrangement, container 22 has a capacity in the
order of 5 gallons, although larger or smaller containers may be
readily employed. The chamber 20 for use with such a five gallon
container will have a maximum horizontal dimension of approximately
eight inches and a maximum vertical dimension of 5 to 6 inches.
Accordingly, the apparatus will continue to operate as long as
there is chlorine within the container 20 to a depth of slightly
more than 5 to 6 inches.
In operation of the device, the chamber 20 is inserted into the
container 22 and the latter is substantially filled with chlorine,
although the chamber, of course, may be inserted into a previously
filled container of chlorine. Conduits 34 and 46 are connected as
indicated in FIG. 1, and the apparatus is then ready for operation.
The pump is off when connection is made to the fittings 30 and 44
and valves 36 and 48 are closed. Accordingly, the high
recirculation pressure at the pump outlet is absent from pressure
fitting 26 and conduit 74 and weight 64 will move (or hold) the
flexible diaphragm 56 to (or in) its lowermost position illustrated
in solid lines in FIG. 2. Before the pump is turned on and valve 36
opened, valve 48 is opened and pressure of the body of supply
chlorine 24 will fill the feed compartment 60 through the inlet
check valve 52, with air being displaced from the feed compartment
through the check valve 40 and via the now-opened valve 48.
Alternatively, chamber 60 may be filled before the dispenser is
connected. Valves 36 and 48 are both open for normal dispensing
operation. Presuming the pump is in operation, or when the pump is
turned on by the timer 18, high pressure at the pump output in
conduit 38 is communicated to the drive compartment 62. The feed
compartment 60 is in communication with a relatively decreased
pressure at point 50, there being a significant pressure drop
across filter 14, either alone or in addition to the pressure drop
across heater 16, it being understood that the water is
recirculating in the direction of the arrows. The pressure
differential across the flexible diaphragm 56 drives the latter
(together with the weight 64) to a second or uppermost position
illustrated in dotted lines in FIG. 2, which position is limited by
abutment of the central portion of the diaphragm 56 against the
lower face 94 of adjustable valve housing 84. The drive compartment
62 fills with pool water via conduits 74, 28, 34. As the diaphragm
moves to its second or upper position, the chlorine in feed
compartment 60 is expelled therefrom through the valve 40, through
valve 48 and mixed with the recirculating water of the pool at
point 50.
The amount of chlorine dispensed into the pool upon this single
operation of the device (e.g. the motion of the flexible diaphragm
from the lowermost position to its uppermost position) is precisely
determined by the difference between (a) the volume of the feed
compartment 60 with the diaphragm in its lowermost position and (b)
the volume of the feed compartment with the diaphragm in its
uppermost position. This difference may be adjusted by varying one
or both of these positions. As shown in the described embodiment,
it is convenient to adjustably vary the upper of these two
positions to either increase or decrease this difference and
thereby increase or decrease the precisely metered quantity of
chlorine dispensed upon each cycle of operation.
As long as the pump continues to operate and high pressure is
provided via conduit 74 to drive compartment 62, the movable wall
or piston that is formed by the flexible diaphragm 56 is and will
remain in its uppermost position. A precisely predetermined
quantity of liquid chlorine has been mixed with the pool water,
being fed directly into the main body of water where it is diluted
before it is recirculated through the pump filter and heater.
Thereafter, when the pump is shut off (by operation of the timer or
otherwise), and only then, the pressure differential across the
flexible diaphragm 56 is removed there being an absence of the high
recirculation pressure at the pump output. The force exerted by the
lead weight is no longer countered by the high pump pressure in
drive compartment 62. Accordingly, the diaphragm and weight move
downwardly to the lower position under the urging of the weight 64
and water in the drive compartment is returned to the system via
conduits 74, 28, 34, since there no longer is a pressure in these
lines sufficient to counter the force of weight 64. Concomitantly,
the decreased pressure in feed compartment 60, which occurs as the
volume of this compartment expands, opens check valve 52 and feed
compartment 60 is once again filled from the body of the supply
chlorine 24 confined in container 22.
The apparatus remains in this condition, the feed compartment 60
being filled and the diaphragm 56 in its lowermost position as long
as the pump remains off. When the pump turns on again, pressure is
again provided to drive chamber 62 which fills with pool water, and
the diaphragm is driven to its uppermost position, thus ejecting
precisely the same quantity of liquid treatment chemical from the
feed compartment 60. If adjustment of the quantity of dispensed
liquid treatment chemical is desired, valve housing 84 is rotated
in its threaded engagement with boss 86 to thereby cause the stop
face 94 of the housing to protrude a further amount or a lesser
amount into the feed compartment 60 to thereby vary the effective
"stroke" of the piston-like flexible diaphragm 56.
As the level of liquid treatment chemical in container 22 decreases
to a point above but adjacent the uppermost point of the supply
inlet conduit 52, the cover 32 may be removed and the supply
replenished. If deemed necessary or desirable, a visual or other
guage may be provided to readily display the quantity of supply
chlorine chemical remaining within the container 22. Where a
swimming pool is to be provided with one pint of liquid chlorine
each day, which is an amount sufficient for treatment of a 20,000
gallon swimming pool under common conditions, and which is
sufficient to bring the chlorination of such a pool to a
concentration of one part per million, a 5 gallon supply container
will require a refill approximately each 30 days, presuming there
is one full cycle of pump operation each day so that each day
precisely one pint of chlorine is dispensed into the pool.
Obviously, larger or smaller containers may be employed. If deemed
necessary or desirable, instead of retaining container 22 in place
and simply refilling it, the container together with the chamber 20
may be provided as a replaceable unit, such that periodically the
apparatus would be serviced simply by replacing the near-emptied
container 22 (with its dispensing chamber 20 therein) with a
freshly-filled container 22 also having a dispensing chamber 20
therein. The emptied container 22 may be removed to some convenient
location for refilling and servicing if appropriate.
It will be readily appreciated that the described apparatus
provides simple, precision and substantially automatic treatment of
a body of recirculating water with exactly predetermined quantities
of treatment chemical at a rate that is not dependent upon a fixed
pressure in the recirculating system. In fact, as the filter
becomes more clogged and pressure increases, a more positive
assurance of chemical dispensing action is obtained in the
described apparatus. Thus, the system is independent of flow rate
or pressure of the normal recirculating system, provided only that
there is sufficient pressure to overcome the weight of the lead
mass 64 and drive the flexible diaphragm to its upper position.
Further, as previously noted, the particular flattened
configuration of the chamber 20 provides for a greater diameter of
diaphragm and a decreased distance of travel for a given volume of
displacement. Thus, the diaphragm needs to flex less since it is
displaced through a shorter distance and will, therefore,
experience a longer life. The flattened configuration allows use of
a greater quantity of the content of the container 22 and, further,
provides for a greater head of the supply liquid to enhance the
refilling of the feed compartment 60.
The drive compartment uses pressure of the recirculating system,
but wastes none of its water since this compartment has connection
only to the recirculating system and returns its contents each time
the pump stops.
The foregoing detailed description is to be clearly understood as
given by way of illustration and example only, the spirit and scope
of this invention being limited solely by the appended claims.
* * * * *