TURBOGEN_Service_Report.pdf

TURBOGEN

CONSULTING SERVICE

ROH FIELD SERVICE REPORT

USS Frank Cable AS-40 Vigor Marine, Portland Oregon

April – December 2017

DATE OF SERVICE: April 5 – 22 December, 2017

SCOPE OF WORK: Provide technical services to accomplish the following work items:

1. Item 208, this item describes the requirement to open and inspect the main propulsion HP Turbine for ABS special survey.

2. Item 209, this item describes the requirement to open and inspect the main propulsion LP Turbine for ABS special survey.

3. Item 303, this item describes the requirement to open, clean, inspect and test the Generators for the 1,2,3,4 Ship Service Turbine Generators (SSTG).

4. Item 503, this item describes the requirement to open and inspect the Steam Turbine and Reduction Gear for the 1, 2, 3 and 4 Ship Service Turbine Generators (SSTG) for ABS Special Survey.

ABSTRACT:

The purpose of this report is to document the details and results of the inspections, Tests and repairs performed. Each item is listed separately in the table of contents in the sequence as work was performed. In a preplanning meeting with the Project Manager, Port Engineer and the Chief Engineer I recommended and it was agreed upon to address the electrical end of the SSTG generators first on each unit, and then proceed with the mechanical portions.

Starting with the SSTG’s followed by the LP and HP Turbines.

TABLE OF CONTENTS:

SECTION DESCRIPTION

I ITEM 303 SSTG GENERATORS

II ITEM 503 SSTG TURBINES & REDUCTION GEARS

III ITEM 208 HP TURBINE

IV ITEM 209 LP TURBINE

V SIEMENS REPORTR #2 SSTG TURBINE ROTOR AND DIAPHRAGMS

VI SEIMENS REPORT #2 SSTG TURBINE CASE

SECTION II

SSTG TURBINES &

REDUCTION GEARS

ITEM 503

No. 2 SSTG TURBINE Delaval Turbine Serial # 654270

Prior to disassembly, turbine bearing clearances and axial clearances were measured, and standard reference point was installed. No major discrepancies were noted during the process of removing the thrust bearing and centering the rotor to lift the upper case. The steam chest cover and valve operating assembly was removed prior to lifting the case.

Lower Casing Inspection Immediately upon lifting the upper case it was apparent that the internals were in poor condition, and strangely there was 4 inches of standing water in the bottom of the case in the first four stages at the HP end after two months of the unit being secured.. Once the cover was completely removed from the unit investigated this abnormality. The steam chest drain was found open which drains the case to the condenser, however, further investigation found that the check valve in the drain line was stuck in the close position.

The only possible cause is an over pressure situation in the condenser.

I believe I can attribute the condition to an incident I was aware of in 2014. I was called out to visit the vessel in Sittahap,Thailand to troubleshoot a mechanical problem on the governor for #1SSTG.

Although the problem was soon attributed to a faulty speed probe, I was made aware that just prior to my visit the had an incident occur that due to loss of cooling water caused the condenser to rupture. Considering there is a 8” relief valve on the turbine that is set to relief at 5 psi, something was awry that the condenser had enough pressure to rupture 3/8” of metal, which I observed at the Fwd end of the auxiliary exhaust plenum. This is what most likely caused the check valve to seat hard in the closed position. Which meant that every time the unit was lite-off it was started and operated at 10,000 RPM in standing water? There are no other drains on the turbine case.

The rotor is severely eroded and pitted, every diaphragm also has some degree of severe erosion, pitting and rust. There was rust particles lying in the bottom between the diaphragms. There is erosion noted in the bottom of the case. In general the lower case is in good condition. The diaphragm sealing surfaces have no rust and are smooth.

#2 SSTG As Found Lower Case

Upper Casing, Nozzle Block, and Intermediate Guide Bucket Ring The casing cover was removed and inverted for inspection and diaphragm removal. Visual inspection noted the same severe erosion on every diaphragm. The guide bucket ring also is eroded and has some tenons that are lifted. The nozzle block shows no discrepancies.

At this point, I requested the Chief and Port Engineer and ABS to examine the condition of the unit and the components. I felt that any attempt to clean or blast the components to perform NDT testing would cause further damage. I requested and recommended that the components be sent to the OEM (Siemens Demag Delaval) for inspection, testing and recommendations. MSC agreed to this proposal. Prior to rotor and diaphragm removal the rotor was placed in running position and axial clearance checks were performed. Results are below;

#2 SSTG AS FOUND AXIAL CLEARANCES

The clearance values on the guide bucket ring are assumed. The proper method to determine this clearance is to have all the diaphragms and seal housings removed. The rotor is installed alone in the case and the upper halve is installed with the guide bucket ring only and the rotor is floated to determine the exact nozzle clearance position in relationship to the rotor. Due to the condition of the rotor and the time it takes to perform this task, it was determined not to perform this task. I do believe, however, that the value of true nozzle clearance is precise by comparing the documentation from the last ROH.

The existing diaphragm and seal housing labyrinth packing was found to be over the maximum design running clearance of 0.020”. Almost all of the seals showed signs of heavy rubbing, which is mostly attributed to starting or running a unit in a bowed condition. The oil seals also showed this condition, and were rubbed so hard the rotor had indentation marks.

Journal and Thrust Bearings Lift checks were performed on each bearing prior to removal and cleaning. Each bearing had acceptable clearance. See following data sheet for clearances.

# 2 SSTG TURBINE BEARING DATA AND AXIAL CLEARANCES

View in direction of Steam Flow

# 2 SSTG HP END STAMPED AS FOUND AS BUILT

BEARING PADS #1 .5004” .500”

#2 .5004” .499” #3 .5004” .499” #4 .5004” .498” #5 .5004” .498”

# 2 SSTG LP END STAMPED AS FOUND AS BUILT

BEARING PADS #1 .5003” .499”

#2 .5003” .499” #3 .5003” .495” #4 .5003” .496” #5 .5003” .498”

AS FOUND AS BUILT DESIGN SPEC MAX

HP END JOURNAL 0.005” 0.005” - 0.007” 0.010”

LP END JOURNAL 0.008” 0.005” - 0.007” 0.010”

HP OIL SEAL 0.012” 0.004” - 0.007” 0.015”

LP OIL SEAL 0.014” 0.004” - 0.007” 0.015”

THRUST 0.015” 0.008” - 0.012” 0.025”

FIRST STAGE NOZZLE 0.055” 0.055” - 0.065”

TOTAL FLOAT 0.162” 0.170” - 0.190”

TURBINE TO REDUCTION GEAR ALIGNMENT

Looking from turbine to gear, dial mounted on gear.

Design spec: turbine 0.003” high and outboard 0.004”, with faces parallel within .002”.

RIM FACE

0.000” 0.000 “

-0.002” -.0006” 0.000” - 0.002”

+0.008” -0.002”

Alignment is acceptable and within the diamonds on the OEM procedure.

Diaphragms and HP Seal Housings Every cap screw holding the seal housings together broke during removal, and every cheese head bolt that secures the upper halve diaphragms also broke off during disassembly. The shipyard provided assistance removing the fasteners and manufactured replacement cheese head bolts. The diaphragms were removed from the upper and lower casings to ship to the OEM. It took numerous hours trying to remove some of the diaphragms especially the last three stages. The upper case had to be heated to expand the fits to remove the last three. Both the broken fasteners and the effort to remove the diaphragms are significant of the amount of heat that this unit experienced when the condenser ruptured. A three hour job took 4 days. I also suspect that there is some distortion in the upper and lower casings that occurred during the incident. I have never experienced this problem in 40 years of doing this work.

The diaphragms, guide bucket ring and rotor were packaged and shipped off to Siemens. Initial reports indicated that the diaphragms could not be repaired it was recommended that replacements would need to be manufactured. The rotor could possibly be saved but it would require a total rebuild. Attached to this report is the 87 page Inspection and Recommendation report from Siemens, referenced by my P.O. # TG170712, dated 8/28/2017. Please review this report for pictures that show the damage to the unit. I saw no need to keep the pictures in this report since the components were viewed by the parties concerned and the Siemens report is much more detailed in narrative and the photo quality. Since it appears this is a long lead time item. No further work on the turbine is to be performed. The internal surfaces were coated with grease. The cover and bearing caps were assembled. Blanks were installed in the bearing housing seals to allow for the units oil system to be operated preventing rusting of the reduction gears and turbine bearing housings. All other components to complete assembly are stowed in a wooden box outboard the unit. The bearings and slip ring brush assembly are in the room port starboard side forward where the SSTG spares are kept.

Inlet Steam Control Valves Below are the measurements taken on the steam inlet controls valve. Valve timing is verified and is correct. Valve seat blue contact check was performed and witnessed by ABS and Ships Force. Contact is acceptable

NDT testing was performed on the steam inlet valves and valve seats in the steam chest cover. No discrepancies were noted on the valves, there was a crack found in the steam chest. I contacted Siemens and sent pictures and asked what could be done. They advised me to grind and additional 1/8” of depth to see if the crack still existed. I did and it was still present. I felt uncomfortable to continue grinding, I advised the factory, who recommended that the case be sent in for inspection and repair. I informed the Port Engineer and Vigor Marine of this recommendation and it was agreed upon that the steam chest would be sent to Siemens for repair. Siemens was able to chase out the crack and the steam chest was returned to Vigor. Attached is the report concerning this repair which show photos of the repair.

Steam Strainer The steam strainer was removed for inspection and cleaning. There were a few small pieces of metal from the spiral of a flexatallic gasket. The strainer basket was dye penetrate tested, results satisfactory no indications of cracks or faults noted. Test results were witnessed by the MSC Rep and ABS Surveyor.

Gland Seal Manifold The gland seal manifold was removed to allow ships force to make repairs. Ships force informed me that they are aware of leak-by issues with two of the valves. The regulator was not touched at all by ships force and is stowed outboard of the unit.

High Speed Coupling Coupling was disassembled and removed for cleaning and inspection. The coupling had moderate sludge build up. The coupling was cleaned. Vigor performed NDT dye penetrate testing on the hubs and spool piece. No indications were noted on the hubs or spool piece. Results were witnessed by the MSC Rep and ABS Surveyor.

Sludge build up on gear end pinion side hole feed holes

No. 2 SSTG REDUCTION GEAR Delaval Reduction Gear Serial # 654271

Casing:

Casing was removed and rigged aside for cleaning and inspection. All oil passages and spray nozzles were found free of obstructions. The sump was drained and opened for cleaning and inspection. The gears are in good shape with some minor rusting.

Rust on Pinion and Bull Gear

Light Scoring on Gear End Pinion Journal

Turbine side pinion journal

Pinion Bearings The pinion bearings were removed and inspected. No discrepancies were noted. Wear patterns are normal. These bearings were installed new in 2012.

As found pinion bearings

Gear Bearings:

The gear bearings were also found in good condition with normal and acceptable wear patterns.

There was some slight scraping on the turbine side to improve contact after picture was taken..

Gen Side Gear Bearing As Found Turbine Side Bearing As Found

Diametrical readings were taken on the journal and bearings along with crown thickness readings.

Note: the bull gear bearings did not have stamped crown thickness readings. See the following sheet for values. Wear patterns and blue contact are satisfactory. The thrust bearing was in excellent condition with no discrepancies noted. All bearings clearances are well within allowable design tolerances.

#2 SSTG REDUCTION GEAR BEARING DATA AND AXIAL

CLEARANCES

PINION BEARING GEAR BEARING

CROWN THICKNESS READINGS

# 2 SSTG TURBINE END PINION BEARING

STAMPED AS FOUND AS BUILT

1 1.001” 1.001” 1.001” 2 .991” .991” .991” 3 990” .990” .990” 4 993” .992” .992”

# 2 SSTG GENERATOR END PINION BEARING

STAMPED AS FOUND AS BUILT

1 1.000” .1.001” 1.001” 2 992” .992” .992” 3 990” .990” .990” 4 993” .992” .992”

# 2 SSTG TURBINE END GEAR BEARING

STAMPED AS FOUND AS BUILT

1 (No Stamped Crown Thickness} 2 “ “ “ 3 “ “ “ 4 “ “ “

# 2 SSTG GENERATOR END GEAR BEARING

STAMPED AS FOUND AS BUILT

1 (No Stamped Crown Thickness} 2 “ “ “ 3 “ “ “ 4 “ “ “

BEARING AND JOURNAL DIAMETRICAL READINGS

#2 SSTG REDUCTION GEAR TURBINE END PINION BEARING

JOURNAL OD BEARING ID CLEARANCE DESIGN SPEC MAX

1 3.994” 4.006” 0.006” 0.005-0.007" 0.009” 2 3.994” 4.006” 0.006” 0.005-0.007” 0.009” 3 3.994” 4.006” 0.006” 0.005-0.007” 0.009”

#2 SSTG REDUCTION GEAR GENERATOR END PINION BEARING

JOURNAL OD BEARING ID CLEARANCE DESIGN SPEC MAX

1 3.994 4.006” 0.006 0.005-0.007" 0.009” 2 3.994 4.006 0.006 0.005-0.007” 0.009” 3 3.994 4.006 0.006 0.005-0.007” 0.009”

Note: Pinion Bearings have two bores The inner bore is true to center, the outer bore is offset 0.007”

#2 SSTG REDUCTION GEAR TURBINE END GEAR BEARING

JOURNAL OD BEARING ID CLEARANCE DESIGN SPEC MAX

1 5.992” 6.000” 0.008” 0.008-0.010" 0.012 2 5.992” 6.000” 0.008” 0.008-0.010" 0.012 3 5.992” 6.000” 0.008” 0.008-0.010" 0.012

#2 SSTG REDUCTION GEAR GENERATOR END GEAR BEARING

1 5.992” 6.000” 0.008” 0.008-0.010" 0.012 2 5.992” 6.000” 0.008” 0.008-0.010" 0.012 3 5.992” 6.001” 0.009” 0.008-0.010" 0.012

AS FOUND AS BUILT DESIGN SPEC MAX

BULL GEAR THRUST 0.018” 0.018 0.010-0.020" 0.040"

PINION AXIAL BACKLASH 0.025 0.025 0.020” New PINION TRANSVERSE BACKLASH 0.048 0.048 0.034" New

Blue Contact Check The gear teeth were hand cleaned and polished of all rust. Blue contact is satisfactory. In fact the bluing from 2012 was still intact . The gear teeth are worn as shown by the backlash readings but this is to be expected considering the age of the units. It took two men 7 hours to clean the teeth. Final blue contact check were performed and results witnessed by Chief Engineer and ABS

Process and results of gear tooth cleaning.

#2 SSTG Gear Tooth Blue Check

No. 3 SSTG TURBINE Delaval Turbine Serial # 654262