Dresser RCS Gebruiksaanwijzing - Pagina 5
Blader online of download pdf Gebruiksaanwijzing voor {categorie_naam} Dresser RCS. Dresser RCS 19 pagina's. Rotary lobe blowers
Pagina afdrukkention from parallel of the inside coupling faces should not
exceed .001" (.03 mm) when checked at six points around
the coupling.
When a blower is BELT DRIVEN, the proper selec-
tion of sheave diameters will result in the required blower
speed. This flexibility can lead to operating temperature
problems caused by blower speed being too low. Make
sure the drive speed selected is within the allowable range
for the specific blower size, as specified under LIMITA-
TIONS.
Belt drive arrangements usually employ two or more
V-belts running in grooved sheaves. Installation of the
driver is less critical than for direct coupling, but its shaft
must be level and parallel with the blower shaft. The
driver should be mounted on the inlet side of a vertical
blower (horizontal piping) and on tlie side nearest to the
shaft on a horizontal blower. The driver must also be
mounted on an adjustable base to permit installig, ad-
justing and removing the V-belts. To position the driver
correctly, both sheaves need to be mounted on their shafts
and the nominal shaft center distance known for the belt
lengths to be used.
Install the blower sheave so that its inner hub face is
not more than
Ya
inch (.3 mm) from the drive end cover.
The shaft fit should be such that the sheave can be work-
ed into place by hand or by very light tapping. A tight or
driving fit can damage a bearing, and may cause internal
blower damage by forcing the impeller out of its normal
operating position. A loose fit or wobbly sheave will cause
vibration, and may result in shaft breakage.
"
The driver sheave should also be mounted as close to
its bearing as possible, and again should fit the shaft cor-
rectly. Position the driver on its adjustable base so that
%
of the total movement is available in the direction away
from the blower, and mount the assembly so that the face
of the sheave is accurately in line with the blower sheave.
This position minimizes belt wear, and allows sufficient
adjustment for both installing and tightening the belts.
After belts are installed, adjust their tension in accor-
dance with the manufacturer's instructions. However, on-
ly enough tension should be applied to prevent slippage
when the blower is operating under load. Excessive
tightening can lead to early bearing failures.
In the absence of belt manufacturer's instructions for
tensioning, the following procedure may be used.
1. With the belts loose, pull the slack on all of them to
the bottom side of the drive.
2. Adjust motor position to tighten belts until they
appear to be seating in the sheave grooves.
3. Thump the belts with your fist. If they feel dead,
tighten them more until they vibrate and feel
springy when struck.
4. Run-in the drive for a short period, after preparing
the blower as instructed in a following paragraph.
While running adjust until only a very slight bow
appears in the slack side of the belts.
5. Stop the motor and compare the tensions of the in-
dividual belts by pressing down firmly with one
hand on the top surface. It should be possible to
deflect each belt only to the point where its top sur-
face is even with the bottom of the other
underdeflected belts.
5
6. A new set of belts should be first tensioned about
Va
greater than normal to allow for stretch and
wear-in. Before putting the drive into normal
operation, increase the tension as obtained above
by a small amount. Recheck after each 8 hour
operating period during the first 50 hours and, ad-
just as necessary.
Before operating the drive under power to check in-
itial belt tension, first remove covers from the blower con-
nections. Make sure the interior is still clean, then rotate
the shaft by hand. Place a coarse screen over the inlet con-
nection to prevent anything being sucked into the blower
while it is operating, and avoid standing in line with the
discharge opening. Put oil in the sumps per instructions
under LUBRICATION.
Before connecting PIPING, remove any remaining
anti-rust compound from blower connections. Pipe used
should be no smaller than these connections, and clean,
new piping throughout is strongly recommended. In addi-
tion, make sure it is free of dirt, scale, cuttings, weld
beads, or foreign materials of any kind. To further guard
against damage to the blower, especially when an inlet
filter is not used, install a substantial screen of 16 mesh
backed with hardware cloth at or near the inlet connec-
tions. Make provisions to clean this screen of collected
debris after a few hours' operation. It should be removed
when its usefulness has ended, as the wire will eventually
deteriorate and small pieces going into the blower may
cause serious damage.
Pipe flanges or male threads must meet the blower
connections accurately and squarely. DO NOT attempt to
correct misalignment by springing or cramping the pipe.
In most cases this will distort the blower casing and cause
impeller rubbing. In severe cases it can prevent operation
or result in a broken drive shaft. For similar reasons, pip-
ing should be supported near the blower to eliminate dead
weight strains. Also, if pipe expansion is likely to occur
from temperature change, installation of flexible connec-
tors or expansion joints is advisable.
Figure 2 represents in diagram form a blower installa-
tion with all accessory items that might be required under
various operating conditions. Inlet piping should be com-
pletely free of valves or restrictions. When a shut-off
valve (not shown) cannot be avoided, make sure a full size
vacuum relief is installed near the blower inlet. This will
protect against blower overload caused by accidental clos-
ing.
CHECK
I
VALVEJ
~
BACK-PRESSURE
SILENCERS MUST BE MOUNTED
REGULATOR OR
WITHIN ONE PIPE DIAMETER
PRESSURE ReliEF
OF BLOWER FlANGE.
VALVE
INLET FILTER ~
~MANUAL
UNLOADING
~-i----~Cl
VALVE
INLET SILENCER \
THERMOMETERS
&
r
PRESSURE GAUGES"
Figure 2 -
Installation With Accessories