Pompetravaini MCU Series, Disassembly & Assembly Instructions, Page: 3 / 20

Disassembly & assembly instructions single stage centrifugal pumps
TC… - MCU-… 3
1 - STEPS TO BE FOLLOWED PRIOR TO PUMP DISASSEMBLY
Should pump repairs be required, it is recommended to acquire full familiarity of the procedures to be followed by
studying these instructions an
d the “Operating Manual for Centrifugal Pumps”.
FOLLOW THE SAFETY INSTRUCTIONS LISTED UNDER CHAPTER 2 OF THE AFORE MENTIONED
OPERATING MANUAL.
It is important to adhere to the following before working on the pump:
- use the appropriate steps to stop the pump
- close the isolating valves at suction and discharge piping
- wear the safety clothing (hard hat, safety glasses, gloves, safety booths, etc.)
- disconnect the electrical power to the motor and all the electrical instrumentation and, if necessary, disconnect the
electrical cables
- if the pump is handling hot liquids, let it cool down to ambient temperature
- drain the pump casing through by removing the drain plugs, rinse the pump with neutral liquid, if required
- adopt all safety precautions when the pump handles hazardous liquids, pollutant or toxic; these liquids
as well as the liquid used for rinsing the pump must be collected and disposed of with the maximum caution
caution and always in compliance with the local safety regulations.
To remove the pump and the motor (if required) from the installation proceed as follows:
- remove the bolts on the suction and discharge flanges
- disconnect any flushing lines, accessories and/or instrumentation connected to the pump assembly
- remove the coupling guard
- remove the coupling spacer, if present
- remove the motor, if necessary, by removing the anchor bolts from motor feet or from the motor flange in the case of
monoblock assemblies
-
remove the pump by removing the bolts from the pump’s feet
- disconnect the pump from the installation with caution, do not damage any components
-
refer to the “Operating manual for centrifugal pumps” for instructions on transporting the pump.
2 - DISASSEMBLY AND ASSEMBLY OF PUMPS SERIES
TCH - TCT - TCA
MCU-CH / CHT / CHA group 1 - 2 - 3
2.1 - DISASSEMBLY
(See the section drawings from fig. 2 to fig. 11 of chapter 8).
Remove the oil from the bearing frame through the draining plug VDMA 903.4 (dispose of the oil in compliance with the
local safety regulations).
Remove the bolts from the studs VDMA 902.2, this allows removal of the rotor from the pump casing. Pumps with vortex
impeller (series TCT and MCU-CHT) are fitted with spacer ring VDMA 110 which must be removed from the casing or
from the casing cover.
Remove the impeller nut VDMA 922 (for cast iron construction) or VDMA 925 (for stainless steel construction) so that
the impeller VDMA 230 can then be removed from the shaft VDMA 210, remove then the key VDMA 940.2.
Pumps with open impeller (series TCA and MCU-CHA) are fitted with two wear plates VDMA 135 and 135.2; to remove
the wear plates the screws VDMA 900.1 and 900.2 must be removed.
Remove the bolts from studs VDMA 902.1, if pump is fitted with mechanical seal, remove the bolts from the studs
VDMA 902 of the seal cover and separate the casing cover VDMA 161 from frame VDMA 330.
The seal stationary face if fitted in the seal cover, remove it if replacement is required.
For pumps with packed stuffing box it is required to remove the nuts from studs VDMA 902.3, remove the seal gland
VDMA 452 attached to the cooling cover VDMA 165 and finally remove the packing rings VDMA 461.
Removal of mechanical seal(s) and of packing should be carried out carefully to prevent damaging any of the various
components. Remove the shaft sleeve VDMA 524 with the seal rotating element still on the sleeve together with the
locating ring VDMA 485. If the locating ring requires replacement be sure to mark its location prior to removal.
For “CARTRIDGE” type mechanical seal insert the seal spacers prior to removal of the seal. The seal spacers will block
the seal with its sleeve, loosen then the set screws that lock seal sleeve to the pump shaft, remove the nuts from the
studs that attach the seal flange to the pump and slide the Seal Cartridge out.
To completely disassemble the bearing frame proceed as described below.
Remove the splash ring VDMA 507. With a gear puller remove the half coupling from the pump shaft and the key VDMA
940. When dealing with Monoblock design remove also the lantern VDMA 341. Remove the two bearing covers VDMA
360.1 and/or 360.2 complete of radial seal rings VDMA 421 and 421.1 or 421.5.
Remove the retaining rings VDMA 932 or bearing nut VDMA 923, applying a slight pressure push the shaft out, together
with the bearings, toward the free end. The pressure should be such that the axially fixed bearing will be removed from
the shaft. The last bearing should be removed from the shaft with the help of a gear puller.