ILRB-3000 GEA20261
RAS and RAS-J WHISPAIR Blowers
Page 10 of 33
• 0.105 inch diameter for 20-inch pipe
• 0.120 inch diameter for 24-inch pipe
For 30” and 36” pipe use 1 mesh backing cloth with a
minimum of 0.180-inch wire diameter for 36-inch pipe.
The table below provides the approximate screen pressure
drop. To determine when the piping needs to be cleaned,
connect a manometer to measure the pressure drop across
the screen. Do not allow the pressure drop to exceed 55
inches H2O. Clean and replace the screen until debris no
longer appears, and then remove the screen. Typically,
screens are installed for the first one to two days of
operation. If the screen is left in place, the wire will
eventually deteriorate and wire fragments may enter the
blower and cause serious damage.
Discharge piping requires a pressure relief valve, and
should also include a suitable pressure gauge and a
manually operated unloading valve. The unloading valve
permits starting under no-load conditions. The optional
back pressure regulator shown in Figure 5 is required if
volume demands vary while the blower operates at a
constant speed. It may be vented if only air is being
handled. Depending on permissible sound levels in the
general surroundings, a vent silencer may be required.
In some installations, particularly when two or more
blowers discharge into a common header, we recommend
that a direct acting or free swinging check valve be
provided in each discharge line. These valves protect
against damage resulting from reverse rotation caused by
back flow through an idle blower.
Carefully line up the mating flanges when making pipe
connections to the blower. They must contact squarely and
accurately, without imposing strain on the blower casing.
Any attempt to draw flanges together by force will likely
distort the blower and cause internal contacts. The blower
should not carry more than the weight of one pipe fitting at
each connection. After bolting up the flanges, rotate the
drive shaft by hand to check for rubbing contacts caused by
strains or dirt.
ILRB-3000 GEA20261 RAS and RAS-J WHISPAIR Blowers.pdf 10
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Summary of Contents for Roots RAS Whispair
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