Evoqua Wallace & Tiernan V-2000 Series, Manual

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Wt.025.055.002.Ua.iM.0814
ManUal Chlorinator - 500lB/24hr
29
eVoQUa W3t110693
4.12.5 Cleaning Injector Throat and Tailway
The injector will not operate properly unless all the ports are clear. This point
is easily checked visually after the throat has been removed.
Water containing carbonates, manganese, or iron will frequently leave a deposit
in injector tailways. As this deposit increases in thickness, it can become scaly
or rough and adversely affect pressure recovery or increase backpressure so
that the injector fails to develop adequate operating vacuum. Such deposits are
readily recognizable by their black or reddish color. They may be removed by
immersing the throats in dilute (10%) hydrochloric acid, known commercially
as muriatic acid.
WARNING: TO AVOID POSSIBLE SEVERE PERSONAL INJURY OR EQUIP-
MENT DAMAGE WHEN USING HYDROCHLORIC ACID, OBSERVE ALL
SAFETY PRECAUTIONS RECOMMENDED BY THE ACID MANUFAC-
TURER/SUPPLIER.
If the upstream strainer becomes corroded or perforated and passes a small
pebble or other tramp material, such particles can partially plug the throat and
prevent adequate flow. Water containing suspended silt or sand particles can
erode the opening in the throat. As this opening is enlarged, the water velocity
decreases, thereby decreasing the vacuum developed.
The injector should develop a dynamic vacuum of at least six inches of mercury
with a flow rate of 500 pounds of gas per 24 hours. At lower feed rates it tends
to be higher for the same hydraulic conditions. With the gas completely shut
off, the static vacuum should be about 25 to 28 inches of mercury.
If the gas feeder fails to operate, inadequate vacuum is the most common
reason and the injector is the first place to check. Proceed as described in
paragraph 4.13.2, Troubleshooting.
4.12.6 Cleaning 3/4" Fixed Throat Injector (Standard) (See Dwg. 25.200.002.010)
The check valve prevents water from the injector from being drawn back by the
vacuum prevailing at shutdown into the control unit and toward the vacuum
regulator during the OFF period.
In continuous or nearly continuous operation, this valve is actuated very little,
and the recommended annual check is principally to ensure cleanliness. In
automatic start-stop operation, the check valve can accumulate thousands of
opening and closing cycles in six months or less and wear becomes a consider-
ation in addition to clean surfaces. For either interval the procedure is as follows:
• Cleaning Injector Unit Diaphragm Backcheck.
a. Shut off injector operating water.
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