Dresser Roots DVJ WHISPAIR, Установка, эксплуатация и обслуживание

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10 | Dresser Roots
Lubrication
A - SEPARATE OPPOSITE GEAR END RESERVOIRS
A simple and reliable splash lubrication system is employed in
ROOTS
®
blowers. All friction parts - gears, bearings and shaft
seals - are lubricated either by dipping directly into oil reser-
voirs or by receiving splash oil from other rotating parts. All
reservoirs require the same grade of oil as specified in Table
3 for various ambient temperature ranges at the installation
site. Reference to the appropriate assembly drawing, Figure
15, will assist in understanding of the following discussion.
At the opposite gear end of the blower, the upper (or driven)
shaft bearing is lubricated from its own oil reservoir, formed
by the bearing carrier (6) and the deep blind end cover (5A).
At a normal oil level, bearing rollers dip into the oil as they
roll through the bottom of their raceway. The oil picked up
is carried over the top by bearing rotation, and some of it
transfers to the shaft behind the bearing to lubricate the
dynamic lip-type inboard seal (27). A slight amount of oil may
work through this seal, but it will be thrown off by the shaft
slinger, and further prevented from reaching the air chamber
by a labyrinth type seal where the shaft passes through the
headpiece. The chamber between the two sealing points
is vented to atmosphere and serves not only to drain any
seal leakage but also to keep the lubrication system at
atmospheric pressure.
At the lower (driving) shaft the arrangement is the same as
described above when a short shaft for direct coupling is
provided. Here an outboard shaft seal (23) is provided in
the end cover (5). On V-belt driven blowers the drive shaft
and bearing carrier (63) are extended and provided with and
additional inboard bearing (60). This creates a larger reservoir
requiring about three times as much oil to fill. Lubrication is
the same as for the shorter shaft, except that two protruding
screws (96) are provided to insure adequate splash oil for
bearing (60).
At the gear end of the blower the bearings, seals and timing
gears are enclosed by a gearbox containing a double
(primary and secondary) oil sump arrangement. In a vertical
style blower the secondary sump is formed of sheet steel
and contoured around the bottom half of the lower gear. It is
fed with oil at a controlled rate from the surrounding primary
sump in the gearbox itself, through a metering orifice in the
secondary wall. The lower gear teeth pick up oil and carry
it to the meshing point with the upper gear, from where it is
splashed onto oil control shields with leaders that direct the
oil to the two bearings. A dam at each bearing maintains
the desired oil level there, with excess overflowing into the
gearbox primary sump. Inboard sealing of the shafts is the
same as at the drive end. In a horizontal style blower the
gear end lubrication arrangement is identical, except that a
secondary sump is formed around each gear and the total oil
capacity is more than doubled.
Note
- A good grade of industrial type non-detergent,
anti-foaming oil should be used when the average of blower
inlet and discharge temperature is 125°F (52°C) or lower.
Oil should be changed after the first 100 hours of operation.
After initial oil change, normal oil change periods under these
conditions may be considered as 2000 operating hours.
Table 3 - Recommended Lubrication Oils
Ambient
Temperature
Viscosity Range, SSu at
100% °F (83 °C)
Above 90 °F (32°C) 1000-1200
32° to 90°F (0°-32°C) 700-1000
0° to 32°F (-18°- 0°C) 500-700
Below 0°F (-18°C) 300-500
During initial operation, install a temporary corrosion resistant
screen at the compressor inlet connection. Screen should be
made of 16 mesh (.020” diameter) wire backed with 2 mesh
wire cloth. Backing cloth-wire diameter shall be a minimum
of 0.063” diameter for 12” pipe, 0.080” diameter for 16” pipe,
0.105” diameter for 20” pipe, and 0.120” diameter for 24”
pipe. For 30” and 36” pipe use 1 mesh backing cloth with a
minimum of .180” wire diameter for 36” pipe. The table below
gives approximate screen pressure drop. A manometer
connected to read pressure drop across the screen will
indicate when it needs cleaning. Do not allow pressure drop
to exceed 55 inches H2O. Clean and replace the screen
until debris no longer appears. Do not leave it installed
permanently, as the wire will eventually deteriorate and pieces
may go into the blower causing serious damage. (Typically,
screens are installed 1-2 days of operation.)
Discharge piping requires a pressure relief valve, and should
also include a suitable pressure gauge and a manually
operated unloading valve. The latter permits starting under
no-load conditions. The optional back pressure regulator shown in figure 5 will be required if volume demands vary
while blower operates at constant speed. It may be vented
if only air is being handled. A vent silencer may be required,
depending on permissible sound levels in the general
surroundings.
In some installations, particularly where two or more blowers
discharge into a common header, it is recommended that a
direct acting or free swinging check valve be provided in each
discharge line. These valves, properly installed protect against
damage resulting from reverse rotation caused by back flow
through an idle blower.
In making pipe connections to the blower, use special care
in lining up the mating flanges. They must contact squarely
and accurately, without imposing strain on the blower casing.
Any attempt to draw flanges together by force will probably
distort the blower and cause internal contacts. Also, 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.