c.
Directional Flow Valve: The input of each vacuum producer shall
have a directional flow valve to prevent back flow of air through
the shutdown. The directional flow valve shall be cast iron with
corrosive resistant internals.
2.22.1.4
Exhaust Silencer
Each vacuum producer shall exhaust to a separate air discharge silencer of
the open-bore expansion type. No interior baffling or shrouding will be
permitted. The silencer shall satisfactorily attenuate air noise to a
level below 85 dB.
2.22.1.5
Controls
The main electric control panel for the system shall consist of the
following: combination across-the-line magnetic starters with time-delay
fused disconnects, running-hour meters to indicate the number of hours each
vacuum producer has been in operation, a manual and automatic alternator to
control starting sequence of the vacuum producers on-off-auto selector
switch for each vacuum producer, automatic start of standby vacuum producer
on system demand, a certified vacuum gauge (kPa inch Hg), red or amber
warning lights with audible alarm to indicate shutdown due to fuse failure,
and separator tank washdown system timers. Controls shall include a
complete low-voltage (24 volts ac) control function with a low-voltage
control panel for remote operation and monitoring of the vacuum producers.
The remote panel location shall be as shown. The low voltage remote
control panel shall contain on-off switch for operation of the vacuum
producers, pilot lights to indicate operation, and a certified vacuum gauge
(kPa inch Hg) to indicate the vacuum within the system at all times.
2.22.1.6
Central Wet Separators
The HVE system shall utilize a central wet separator. Separator tanks
shall be constructed of a nonmetallic, noncorrosive, inert material or
composite such as glass-reinforced plastic (GRP). Tanks shall be of
one-piece construction, with smooth, interior walls. Tanks shall be
freestanding. [One tank] [Two tanks] shall be provided with each tank
having a capacity of [_____] liters gallons. Tanks shall be high-pressure
vessels able to withstand a constant negative pressure of 51 kPa 5 inch Hg.
The tops of the tanks may be convex or concave. The bottom of the tanks
shall be convex with drain at the apex of convexity. The inlet shall be
tangential to effect a cyclonic separation of air, water and waste.
Separator tanks shall be equipped with mechanical overflow protection,
which shall be preplumbed with a 360 degree nozzle internal washdown system
with timer. The washdown system shall include a 115 volt ac
automatic-flush clock-controlled mechanism which shall effect a complete
washdown of the interior of the separator at any predetermined time of day
or night. Washdown time shall be adjustable for up to at least 3 minutes.
The timers shall be in the main electric control panel. The cold water
supply to the automatic tank flush unit shall be equipped with an in-line
filter with 40-mesh stainless steel screens. Filter shall be supplied as
part of the HVE system. Each separator tank shall be equipped with an
electronic high-low liquid level sensor which shall perform as the primary
overfill protector. In multiple-tank installations, one tank shall be
adjusted to sense 90 percent of its capacity and the other tank 100 percent
of its capacity via the liquid-level sensing devices. Each sensor shall
control a 115 volt ac electrically operated output air solenoid valve
located to control the outgoing air from the tank to the vacuum producer.
Each tank shall be equipped with a gate and swing type check valve at the
SECTION 15405A
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