CAMCORP HVP with Roots Blower - Manual (Page 53)

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smaller than unit connections. In addition, make sure it is
free of scale, cuttings, weld beads, or foreign material of any
kind. To further guard against damage to the unit, especially
when an inlet filter is not used, install a substantial screen of
16 mesh backed with hardware cloth at or near the inlet con-
nections. Make provisions to clean this screen of collected
debris after a few hours of operation. It should be removed
when its usefulness has ended, as the wire will eventually
deteriorate and small pieces going into the unit may cause
serious damage.
Pipe flanges or male threads must meet the unit connections
accurately and squarely. DO NOT attempt to correct mis-
alignment by springing or cramping the pipe. In most cases
this will distort the unit casing and cause impeller rubbing.
In severe cases it can prevent operation or result in a broken
drive shaft. For similar reasons, piping should be supported
near the unit to eliminate dead weight strains. Also, if pipe
expansion is likely to occur from temperature change, instal-
lation of flexible connectors or expansion joints is advisable.
Figure 3 represents an installation with all accessory items
that might be required under various operating conditions.
Inlet piping should be completely free of valves or other
restrictions. When a shut-off valve can not be avoided, make
sure a full size vacuum relief is installed nearest the unit inlet.
This will protect against unit overload caused by accidental
closing of the shut-off valve.
Need for an inlet silencer will depend on unit speed and pres-
sure, as well as sound-level requirements in the general sur-
roundings. An inlet filter is recommended, especially in dusty
or sandy locations. A discharge silencer is also normally
suggested, even though Whispair units operate at generally
lower noise levels than conventional rotary blowers. Specific
recommendations on silencing can be obtained from your
local ROOTS distributor.
Discharge piping requires a pressure relief valve, and should
include a manual unloading valve to permit starting the unit
under no-load conditions. Reliable pressure/vacuum gauges
and good thermometers at both inlet and discharge are rec-
ommended to allow making the important checks on unit
operating conditions. The back-pressure regulator shown in
Figure 3 is useful mainly when volume demands vary while
the unit operates at constant output. If demand is constant,
but somewhat lower than the unit output, excess may be
blown off through the manual unloading valve.
In multiple unit installations where two or more units operate
with a common header, use of check valves is mandatory.
These should be of a direct acting or free swinging type, with
one valve located in each line between the unit and header.
Properly installed, they will protect against damage from
reverse rotation caused by air and material back-flow through
an idle unit.
After piping is completed, and before applying power, rotate
the drive shaft by hand again. If it does not move with uni-
form freedom, look for uneven mounting, piping strain,
excessive belt tension or coupling misalignment.
DO NOT operate the unit at this time unless it has been lubri-
cated per instructions.
Motor On Inlet Side of Blower (Top Shaft)
Motor On Inlet Side of Blower (Bottom Shaft)
Motor On Discharge Side of Blower (Top Shaft)
Motor On Discharge Side of Blower (Bottom Shaft)
INLET DISCHARGE
Top Shaft
INLET DISCHARGE
Bottom Shaft
Motor On Drive Shaft
Side of Blower
INLET
DISCHARGE
Driven Shaft Drive Shaft
INLET DISCHARGE
Top Shaft
INLET DISCHARGE
Bottom Shaft
Motor On Driven Shaft
Side of Blower
INLET
DISCHARGE
Drive Shaft Driven Shaft
Acceptable Blower Drive Arrangement Options
ACCEPTABLE UNACCEPTABLE