Evoqua Wallace & Tiernan V-2000 Series, Руководство пользователя, Страница: 30 / 110

Wt.025.055.002.Ua.iM.0814
ManUal Chlorinator - 500lB/24hr
16
eVoQUa W3t110693
3.2.5 Preparation for Winter Shut-Down
If the gas feeder is to be shut down for an extended period during freezing
weather, the following procedure must be followed:
a. Operate the injector with the gas supply turned off at the supply container
valve(s) until the supply vacuum gauge reads full scale and the rotameter
float settles on the bottom stop.
b. Shut off the water supply and drain the line to the injector.
c. Drain the solution discharge line and prevent any water flow into the line.
d. Drain any water in the injector.
NOTE: If the control module is to be removed for storage, seal the gas inlet
fitting and all gas lines with rubber stoppers to prevent the entrance of at-
mospheric moisture during the storage period. If a pump is used, follow the
pump manufacturer instructions for extended shut-down.
3.3 Theory of Operation
Evoqua Water Technologies gas feeders and accessories are designed to control
and indicate the rate of flow of chlorine, to provide a simple means of manually
setting the feed rate at any value within the range of the machine, to mix the
gas with water, and to deliver the resultant solution to the point of application.
In the gas feeder described in this manual, the function of the injector is to
produce a vacuum to draw gas from the control module and to mix this gas
with the water flowing through the injector. A poppet check and diaphragm
check are built into the injector to prevent a back flow of water into the control
module if the injector water supply is shut off with pressure on the injector
discharge or if the injector discharge line is restricted. Proper operation of the
injector is dependent on the inlet pressure being sufficiently higher than the
discharge pressure. In the control module, the differential regulating valve
throttles the injector vacuum to maintain a constant drop across the V-notch
variable orifice. Thus the flow through the orifice is entirely a function of the
size of the orifice as determined by the position of the V-notch plug as manu-
ally set by the operator.
From the vacuum regulator, gas under a controlled vacuum passes through a
rotameter (feed rate indicator) causing the float to indicate the rate of flow
on an easily read scale. As stated above, the rate of flow is controlled by the
position of the V-notch variable orifice, across which a constant differential
at less than atmospheric pressure is maintained by the operation of the dif-
ferential regulating valve. From the differential regulating valve, gas passes to
the injector where it is mixed with water. The resultant solution is discharged
to the point of application.