the water meter and the speed at which the
hypochlorinator pumps will be in direct proportion
a. Hypochlorite Solution. The hypochlorinator is
to the amount of water passing through the meter.
designed to pump hypochlorite solution and in most
The pumpage will vary to suit the flow of water
cases, best results will be obtained by making
being treated.
solution from high-test hypochlorites which are dry
b. Balancing Water Valve.
powders, usually conveniently packed in small
(1) The main elements of the balancing water
containers. Normally, only a part of the
valve are a diaphragm, a valve seat rigidly fastened
hypochlorite in a can will be used for each batch of
to the diaphragm, a valve stem, and a spring. The
solution. It is extremely important that the excess
discharge connection from the valve is connected to
chemical be stored in dry airtight containers in a
a balancing chamber behind the pumping head
dry storage space.
diaphragm. The hypochlorinator pump shaft is
b. Strength of Solution.
hollow and is also drilled, Water from the balancing
(1) W h e n t h e p o r t a b l e a u t o m a t i c
chamber can escape through the shaft to the waste
hypochlorination unit is first placed in operation on
area during the suction stroke when the valve at the
water whose chlorine requirements are unknown, a
driving yoke end of the shaft is open. It should be
certain amount of experimenting will be necessary.
noted that the balancing valve stem can never
This is necessary to determine the hypochlorite
completely shut off the water flow through the
solution strength which will best accomplish the
balancing valve seat.
desired results. Two factors determine the amount
(2) During the hypochlorinator suction stroke,
of chlorine which is added to a given volume of
the valve on the end of the pump shaft is open. No
water when it is treated with hypochlorite solution.
pressure exists in the balancing chamber behind the
One is the volume of hypochlorite solution used,
pumping head diaphragm, Water pressure on the
and the other is the strength of the solution. For
inlet side of the balancing diaphragm pushes the
example, 60 gallons of 0.5 percent hypochlorite
diaphragm forward so that the valve seat is against
solution contains the same amount of chlorine (2.5
the valve stem, Under these conditions, the only
pounds) as 30 gallons of 1.0 percent solution. If the
flow through the valve is the leakage past the stem.
volume of water being treated requires 2.5 pounds
When the hypochlorinator pressure (forward)
of chlorine per day to produce the required chlorine
stroke begins, the driving yoke integral valve seat
residual; it may be treated with either 60 gallons
moves against the open end of the pump shaft, thus
per day of 0.5 percent solution or 30 gallons per
sealing the hypochlorinator balancing water
day of 1.0 percent solution. At a speed of 12 strokes
chamber. The leakage through the balancing valve
per minute, the hypochlorinator will pump 60
is then trapped and pressure begins to build up in
gallons of solution per day when the stroke control
the balancing chamber and therefore, on the
is set at "10" on the dial. It will pump 30 gallons
discharge side of the balancing valve diaphragm.
per day with a setting of "5" on the dial. It is more
When the discharge pressure on the diaphragm
desirable to operate the hypochlorinator with a
approaches the pressure on the inlet side of the
weak solution and a long stroke rather than with a
diaphragm, the diaphragm and the valve seat are
strong solution and a short stroke.
pushed away from the valve stem by the spring.
(2) A 1.0 percent hypochlorite solution
The balancing valve then passes enough water to
contains 1 part by weight of available chlorine in
maintain a pressure in the balancing chamber
100 parts by weight of solution. In calculating
behind the main diaphragm about equal to the
solution strengths, it should be noted that 1 ounce
pressure which exists in the hypochlorinator
of calcium hypochlorite powder contains 0.7 of an
discharge line. The foregoing operations take place
ounce of available chlorine. For field operation,
rapidly so that pressure is built up in the balancing
a s s u m e that the addition of 10 ounces of
chamber almost immediately after the beginning of
hypochlorite powder to 5 gallons of water will
the pressure stroke.
produce a 1.0 percent hypochlorite solution.
c. Flow Controller, The flow controller is a
(3) Figure 2-6 gives the relationship between
spring-loaded diaphragm and needle valve. When
the flow of water to be treated and the volume and
an increase in inlet water flow occurs, the flow
strength of hypochlorite solution required to
controller diaphragm moves the needle valve
produce various chlorine treatments. In using the
toward its seat, thus causing a reduction of flow at
chart, remember that the figures labelled PPM
the valve outlet.
(part per million ) refer to chlorine dosage and not
d. Water Pressure Regulating Valve (fig. 2-3).
chlorine residual. "Dosage" indicates the total
The water pressure regulating valve has a spring-
amount of chlorine added to the water. "Residual"
loaded diaphragm which holds the valve closed
refers to the amount of chlorine remaining in the
until a pressure of at least 10 psi exists under the
water after the chlorine and water have been in
diaphragm.
