All pump parts should be cleaned and prepared for short term storage by applying a rust preventive to all machined surfaces which are not made of stainless steel. Recommended rust preventives are given under 3.2.3 part II. Protection of the interior of the pump.
Handle the pump shaft with care and wherever possible store shaft by hanging vertically to maintain staightness.
Inspect all parts for wear or damage, see 7.5.
ATTENTION
ATTENTION
Sketch 7.4-5
Disc
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7.4 Overhaul – Dismantling of the pump (Brg. Bkt. - 6 to 8)
When overhauling a pump it is advisable to procure all necessary spare parts (wearing parts) well beforehand to minimize the down time. When ordering spare parts it is essential to give an exact description of the part, its part number, the pump type and serial number (see the duty plate).
References Refer to specific drawings (section drawing(s), parts lists, installation plan).
Note: These pumps should only be disassembled by qualified specialis ts with suitable tools and by strictly
observing the instructions. All assembly works have to be carried out with the greatest possible care. Negligence leads to premature failure of the pump.
Preliminary work
- Close the suction and discharge valves and secure them against unauthorized opening. - Let hot pumps cool down to ambient temperature before disassembly.
- Isolate the driver to prevent start -up
With electrical driver: Remove residual current (take away safety fuses). Have electrical connections disconnected by an electrician.
- Drain the pump (position of drain screw see installation plan)
The draining of the pump from toxic, explosive, hot or otherwise dangerous fluids must not lead to any endangering of operator(s) and environment. Observe legal provisions for disposal.
In case the pump delivered aggressive, toxic or otherwise dangerous media, it has to be flushed carefully, to be cleaned on the outside and to be decontaminated in the case of radioactivity.
If the pump is sent to the manufacturer to be repaired, the cleaning/decontamination has to be carried out before transport. A certificate attesting that it is absolutely safe must be included.
The service personnel will have to be careful however inspite of this, as even in the case of a thorough flushing and cleaning, residues of the fluid may leak out.
- Remove the coupling guard and separate the coupling halves, remove spacer - Remove any instruments and ancillary pipes
- Disassemble pump and take it to assembly site - Drain off oil from bearing brackets
Dispose of used oil acc. to legal regulations. Never put it into the sewage system.
Dismantling of the assembly unit - rotor/shaft sealing/bearing
(see sketch 7.4-1) Pay attention to hazardous situations during dismantling, e.g. take care to stand firm, secure assembly parts against dropping, support or prop loose parts, hang on crane etc.- If present: Loosen bearing bracket support foot (183.01) from baseplate.
- Run a rope through eyebolt (910.01) of the bearing bracket and secure it through a crane. Note: The eyebolt may not in the center of gravity.
- Remove hexagonal nuts (920.01) fastening the casing cover (161.01) (shaft seal casing) at the pump casing (102.01)
- Press assembly unit (consisting of bearing bracket, rotor and shaft sealing) out of its seat in the pump casing by use of jack screws and draw out completely (for heavier units use crane).
Pull Jack screw Eyebolt (910.01) Nut (920.01) Stud (902.01) Case (102.01) Sketch 7.4-1
1700/e7-4-01-000 page 2
Disassembly of the assembly unit
Dismantling of impeller (see sketch 7.4-2)
- Lock pump shaft and remove impeller nut (922.01). Note: The impeller nut has a right-handed thread to tighten against rotation. In case the impeller nut is provided with an additional hexagon head screw (901.10), remove it beforehand (see pertaining section drawing). - Draw off impeller (230.01), remove key (940.01). Note: Impeller is a
slip fit, however, a puller may be required. If necessary, apply heat.
Dismantling of the shaft seal
Disassembly of soft packing
- Remove the hexagonal nuts (920.03) tightening the gland (452...)
- Screw off bearing bracket fastening screws (920.02), disconnect casing cover (161.01) (shaft sealing casing) from bearing bracket (330...) (if necessary, hit cautiously with leaden sledge hammer against flange) and take off
- Remove rings of gland packing (461.01) from shaft sealing Chamber
-
Push shaft protection sleeve (524.01) off the shaft, as the case may be, drive it off shaft with suitable auxiliary tool (flat bar or hammer)- Take away gland (452...)
Dismantling of mechanical seal standard type (see sketch 7.4-3)
- Loosen mechanical seal cover from casing cover (161.01) (shaft seal casing), remove all the fastening screws.
- Unscrew bearing bracket fastening nuts (920.02), disconnect casing cover (161.01) (shaft seal casing) from bearing bracket (330...) (if necessary, hit cautiously with leaden sledge hammer against flange) and take off.
-
Push shaft sleeve including the rotating parts of the mechanical seal off the shaft (if necessary, drive off cautiously) and take away mechanical seal cover with stationary parts of the mechanical seal.- For double mechanical seals (back-to-back or tandem type): Disassemble stationary parts of the internal seal inside casing cover (shaft sealing casing), see section drawing of shaft sealing.
Disassembly of mechanical seal Cartridge type (see sketch 7.4-4)
- Loosen assembly straps at mechanical seal cover, push them into the groove of the shaft sleeve and fasten again.
Please note the following so as to avoid any damage to the components of the mechanical seal: If the assembly straps cannot be placed in the previsaged position because the shaft sleeve grove sticks out too far from the mechanical seal cover, the fastening of the mechanical seal cover has to be disconnected. If the shaft sleeve groove is too far inside the bore of the mechanical seal cover, the fastening of the bearing bracket at the casing cover (shaft sealing casing) has to be loosened in such a way as to allow moving the assembly straps into the the shaft sleeve groove without any difficulty.
- Screw off bearing bracket fastening nuts (920.02), disconnect casing cover (161.01) (shaft seal casing) from bearing bracket (330...) (if necessary hit cautiously with leaden sledge hammer against flange) and take off together with Cartridge mechanical seal.
ATTENTION
Sketch 7.4-2
Cartridge
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-
Remove the fastening screws of the mechanical seal cover and draw the complete mechanical seal (Cartridge) out of the casing cover (161.01) (shaft seal casing).-
After loosening and moving the assembly straps back the mechanical seal can be disassembled into its single parts. WARNING: The mechanical seal cover is prestressed by internal springs.Disassembly of the pump shaft and bearing
- Remove coupling half on pump side, take off key (940.03). Seesketch 7.4-5.
To avoid damage to the bearings or to the shaft centering thread use a suitable puller and protect the shaft centering thread by a disc. The bearings must by no means be subjected to any pressure or shock.
- In case of fan cooling: Remove fastening screws (900.06) of fan cover (832.01) and take it off. Take circlip (932.02) out of shaft groove by means of spring ring pliers, push fan (831.01) off the shaft and remove key (940.04).
- Loosen grub screws (904.05 and 904.06) at the deflectors (507.01 and 507.02), take off deflectors. - Remove fastening screws (901...) of the bearing cover (360...) on impeller and coupling side, take away
bearing cover. Note: The bearing cover on the coupling side is prestressed by internal springs.
- Remove shaft nut (923.01) and drive out shaft by careful blows with plastic hammer. Note: The shaft nut has a left-handed thread (unscrew in clockwise).
To avoid any damage to the bearings, with bearing bracket size 6 to 8 (thrust bearing in x- configuration), drive out shaft from coupling side into direction of the impeller side. Take care to protect the shaft end from damage.
- Draw off inner race of radial bearing (320.01) from shaft, using a suitable puller or press.
- The thrust bearing (320.02) and the outer race with rollers of radial bearing (320.01) will be left in the bearing bracket, remove separately. Push thrust bearing together with ring (500.13) and springs (478...) from impeller side into direction of coupling side out of bearing bracket. Remove radial bearing outer race with rollers toward impeller side.
- Remove circlip (932.01) and detach oil ring (644.01) from bearing housing through outboard bearing bore. - In case of water cooled bearing bracket (330.02), remove hexagon socket screws (914.01), dismantle
cooling jacket (116.01) and clean cooling chamber.
After disassembly
All pump parts should be cleaned and prepared for short term storage by applying a rust preventive to all machined surfaces which are not made of stainless steel. Recommended rus t preventives are given under 3.2.3 part II. Protection of the interior of the pump.
Handle the pump shaft with care and wherever possible store shaft by hanging vertically to maintain staightness.
Inspect all parts for wear or damage, see 7.5.
ATTENTION
ATTENTION
Sketch 7.4-5
1700/e7-5-00-000 page 1
7.5OVERHAUL - INSPECTION OF WEAR PARTS
Check all parts for wear, if necessary remachine or replace them.
Impeller
Inspect impeller for wear or damage. Look for cavitation marks (pits) in the suction area, erosion of vanes and cracks in the shroud. Smooth minor irregularities with a fine file or emery paper, replace impeller, if necessary.
Wear rings and clearances
Inspect wear rings for grooves and uneven wear. Check impeller clearances. The minimum and the maximum (worn) diametrical clearances are give n in the table below.
Replace wear rings, when pump performance drops below acceptable system standard or the recommended maximum clearances have been reached or exceeded.
Remark: Each clearance enlargement causes efficiency loss in pump. Wear ring diameter in (mm) up to 75 from 75
to 140 from 140 to 200 from 200 to 320 from 320 to 400 from 400 to 600 Index Min. clearence in mm * 0.3 0.4 0.5 0.6 0.7 0.8 1)
(with new parts) 0.5 0.6 0.7 0.8 0.9 1.0 2)
Max. clearence in mm * 0.9 1.2 1.5 1.8 2.0 2.5 1)
(with worn parts) 1.5 1.8 2.0 2.5 2.8 3.0 2)
* clearence in relation to diameter
Index:
1) Standard clearances: For cast iron,11-13% chromium or soft nitrided (wnt) and materials of similar low galling tendencies.
2) Hot clearances: For material with greater galling tendencies (stainless steel) and /or operating temperature above 260 oC.
Measure the clearance between corresponding sets of rotating and stationary parts. Use several measurement locations, then calculate the clearance as described below.
Largest casing wear ring ID – smallest impeller OD = diametrical clearance