Torishima Pump MML - Stuffing Boxes Leak; Excessive Bearing Temperature; Excessive Wear of Balancing Device

4. 5. 5. Stuffing box leak
Possible cause Remedy
1. Worn, unsuitable or badly fitted packing. Repack the stuffing box, carefully observing instruction on page
16.
2. Scoring or grooving of the shaft protecting sleeve, due to
excessive tightening askew of the stuffing box gland.
The shaft protecting sleeve should be repolished or renewed.
When the stuffing box has been repacked, tighten the gland
carefully and evenly.
3. Insufficient cooling water, or fouling of cooling water
chambers.
Remove cooling water covers, and thoroughly clean out the
cooling surfaces in the stuffing box. Make sure that an adequate
supply of clean cooling water is available.
4. The pumps runs rough, i.e. the shaft chatters. No stuffing box can remain tight forever if the shaft chatters. Firs
of all; the coupling alignment and bearing clearance should be
checked, and new bearings fitted if necessary. If this does not
cure the trouble, open up the pump, and check the shaft for true
running. Also rebalance the rotating assembly and check all
running clearances. When reassembling the pump, carefully
follow the instruction in this manual.
4. 5. 6. Excessive bearing temperature
Possible cause Remedy
1. The set is misaligned. Check alignment at the coupling as described in Section 3.2.1.
2. The piping causes the pump to warp. Ensure that the piping transmits no stress or strain onto the
pump by altering the piping layout if necessary. Realign the
pumping set.
3. The prescribed clearance between coupling halves
has not been observed during erection.
Correct the coupling clearance. See foundation drawing for
measurements.
4. Oil level inadequate, or inferior oil quality. Top up, or change if necessary (see 4.4.4).
4.5.7. Excessive wear of balancing device
Possible cause Remedy
1. The fixed clearance gap between the rotor and the
discharge casing (1070), or on pump sizes MML 200-
350 the bush (118) is too wide; this may be caused by
corrosion or mechanical wear.
Re-establish the correct radial clearance between the parts
concerned, and renew bush (118) if required. Check that the
bearings have correct clearance and seat properly. Check the
shaft for true running, and if necessary fit a new shaft.
2. Thrust balancing is impaired by reason of an excessive
clearance between the impeller neck (2300) and the
wear ring (5020) or the diffuser (1710) ; on pump sizes
MML 200-350, between diffuser bush (119) and spacer
sleeve (5210).
True up impeller neck or bore of the diffuser and renew wear ring
(5020) or spacer sleeve (5210).
3. Thrust balancing impaired by reason of axial
displacement of the impellers in relation to the diffusers.
Re-establish the correct axial location of the rotating assembly
by either lengthening or shortening the spacer sleeve (5252) in
the discharge casing, or in the case of pump sizes MML 40-125,
adjust the hub of the balance disc (fig. 21).
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