26 Nov Sulzer MC80-260/11 Overhaul
Pump description
The Sulzer MC80-260/11 is a very adaptable pump of a modular design. Most commonly the MC80 is a boiler feed pump or other style of high-pressure centrifugal pump, up to a temperature of 180°C and a maximum of 180bar.
When the MC80-260 has more than 8 stages then the pump has to be adjusted to the deflection line of the shaft; this is to prevent hogging of the MC’s shaft. Fitting a special conical stage casing in place of one of the normal stage casings does this.
The MC80-260 can come with a Balance Drum and Balance Liner or a Balance Disc and Balance Ring arrangement dependent on the duty of the pump
Dismantle
All the preliminary dismantling was completed on site before transportation to our workshop in WA.
Once we had received the Sulzer MC80 in our workshop and completed initial measurements i.e. the bearing axial clearance, we started the process of carefully dismantling the pump paying special attention to the removal of the bearing housings. It has been known that in same cases people have badly damaged these housings, as you have to remove the bearings and bearing housings together.
Industry
Power
Application
Boiler Feed Water Pump
Location
South Australia
Equipment Details
SULZER MC80-260/11
Mandate
Carry out major overhaul, investigate upgrade options.
Outcomes
Overhaul completed, upgrades installed, pump installed and commissioned successfully.
MC80 with DE and NDE removed
MC80 260 DE bearing housingAs soon as the pump was completely dismantled we move on to inspect and report on our findings.
Inspection
We inspected and reported on all parts of the Sulzer MC80-260/11 to clarify if the were within specification or not some of which:
Shaft – inspected for concentricity of the shaft making sure it came within the permissible run out of 0.025mm, also damage and cracking.
Impellers – impeller clearances to see if max clearances have been exceeded also checking for corrosion damage, wear and cracking.
Stationary Case Rings – stationery case ring clearances to see if max clearances have been exceeded also checking for corrosion damage, wear and cracking.
Interstage Bushes – interstage bush clearances to see if max clearances have been exceeded also checking for corrosion damage, wear and cracking.
Balance Drum / Balance Drum Liner – we checked outer diameter on the balance drum and inner diameter of the balance drum liner for allowable clearance and damage.
Stage Casings – stage casings measured to see if max tolerances had been exceeded also checking for corrosion damage, wear and cracking.
The client was given full reports including as received data, photo, concentricity, and component dimension sheets.
Repair
Interstage Bushes (Wear Rings) – manufactured the interstage bushes undersize so we only needed to skim the Impeller hubs.
Stationary Case Rings (Wear Rings) – manufactured new standard size case rings, as there was no excessive wear on the impeller wear diameters on the suction side of the impellers.
Balance Drum – manufactured new balance drum standard size as old one was badly warn.
Balance Drum Liner – manufactured new balance drum liner standard size as old one was badly warn.
Stage Casings – upgraded the stage casings due to the evidence of severe corrosion on diffuser mating face, we did this by machining the face from the stage casing and manufacturing a changeable wear plate from a much harder material.
Suction casing sowing signs of excesive water erosion.
Pumpteq upgrade of case element wear plateRebuild
Before the final rebuild was undertaken we completely built the rotating element, checked its concentricity and dynamically balanced it to a standard of G1.0.
Rotating element after balancing.
Rotating element dynamically balanced it to a standard of G1.0.During the rebuild one major step we had to pay close attention to was the axial position of the pump. This is because in order to achieve the most favorable hydraulic efficiency from the pump we must make certain that the impellers and diffusers are in their optimum position to each other.
Measurement of theoretical axial position of the rotating element was necessary, as we had fitted the Pumpteq upgraded wear faces to the case elements thus possibly changing the original length of the pump.
Once we had assembled the hydraulic part of the pump, making sure the tie rods had been torqued to the correct torque, we fitted the balance drum sleeve and balance drum, mechanical seals, seal plates and bearing brackets.
When happy with the set up we went onto the fitting of the drive end bearing and non-drive end antifriction bearing with intermediate ring, making sure that one bore of the intermediate ring pointed downwards.
Non-drive end antifriction bearing with intermediate ring.To allow the oil film between bearing parts and for heat expansion purposes it is imperative to have the correct bearing axial clearance this was done by placing a clock axially on the end of the shaft non-drive end.
The pump was then competed, painted, boxed and transported back to the client.
The client was given full reports including as received data, photo, concentricity, and component dimension sheets.
Project Conclusion
The Sulzer MC80-260/11 has been commissioned on site and is performing back to its original performance cure.
PROJECT IMAGERY
Sulzer MC80-260/11
Onsite Pump Services.
MC80 Rebuild
Pump Repairs.
Interstage Bush
Pump Repairs.
View of Balance Drum Liner
Pump Repairs.
Stage Casings
Pump Re-Engineering.
Balance Drum Liner
Parts/Manufacturing.
Clients Sulzer MC80-260 11 stage boiler feed pump had decreased in performance and was in need of an overhaul.
Whilst in service on a plant in SA. This fluid coupling is situated between a Siemans three-phase motor and a 6”/8” 10 stage boiler feed pump.
The unit was suffering from a large amount of vibration and was unable to adjust its speed.
The Re-Engineer of Case Wear Rings for Horizontal Split Case single Stage Double Suction Pump (CCW).
One of our clients contacted us stating they were having major issues with one of their Peerless closed cooling water pumps, with the DE bearings failing.
Due to recent pump failures and the findings of both mechanical component and gasket / o-ring condition a change of seal type is recommended.
Failing of mechanical seals can have major implications on the performance of pumps. Here we look at a client whose power station has 12 booster pumps that feed their Sulzer HPT Pok30 boiler feed pumps where they have suffered numerous seal failures.
Swirl breaks are designed into high energy centrifugal pumps (especially modern Boiler Feed Pumps) to dampen vibrations especially at higher speeds caused by rotor dynamic forces.
Pump types come in two main categories – Centrifugal Pumps and Positive Displacement Pumps as classified according to the method of how the energy is imparted to the fluid – Kinetic Energy or Positive Displacement and again each of these categories having many pump types….