Dresser Roots DVJ WHISPAIR, Установка, эксплуатация и обслуживание

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18 | Dresser Roots
7. Tighten each screw quarter turn at a time in either
clockwise or counter-clockwise sequence, but not
diametrically opposite sequence, till the outer ring is solid
against the inside ring.
THE GEAR SHOULD MOVE
.065 to .075".
8. Loosen up the installation capscrews and remove the
gear installation tooling.
9. Install gear locknut and tighten nut with a spanner
wrench.
C - TIMING THE IMPELLERS
1. Disconnect the piping at both inlet and discharge
flanges of the machine, moving the pipe flanges at least
far enough away for easy insertion of an arm into the
openings.
2. Use a set of feeler gauges with blades about 12” (300
mm) long for measuring clearances between the impeller
lobes. These clearances are identified as “front” and
“backs”, and are measured with the impellers in the
positions shown in Figures 12 and 13. The drive shaft
rotation indicated is
counter-clockwise . For opposite
rotation, impeller positions will be reversed from that
shown in Figures 12 and 13 and the front and back iden-
tifications will be interchanged. Fronts may be defined as
the lobes that tend to contact during rotation because
of pressure load and gear tooth wear; conversely, backs
are the surfaces that tend to separate.
3. Determine and record the total lobe clearance by
measuring the front and back clearances and adding
them. It will normally be satisfactory to take these
measurements at the mid-point of the impeller length.
Place a wedge between the gear teeth to prevent the
impellers from shifting during the measurement, making
sure that any gear tooth clearance is always taken up
in the same direction.
Note that there are two front
and two back clearance positions in one complete
revolution, use minimum value of clearance found
along length of impeller for fronts and backs
throughout 90° rotation.
4. Loosen the screws on one gear (make sure collars are
loose) to permit slight adjustments of position rela tive
Figure 9 - Taper Gear Installation
Figure 10 - Outside Ring Material,
Steel, Hardness - Rc-25 min
Figure 11 - Inside Ring Material,
Steel, Hardness - Rc-25 min
Figure 12 - Impeller Timing Viewed from
Standard Rotation
Figure 13 - Impeller Timing Viewed from
Standard Rotation