In this unit, the HP-IP section contains 12 stages. LPA and LPB each have 7 stages per flow, stages 13 through 19.

All LPB components were sent to MD&A’s Turbine-Generator Repair Facility in St. Louis, MO for immediate incoming inspection, analysis, and recommendations.

Couplings and journals

The rotor was blast-cleaned followed by visual, non-destructive examination, and dimensional assessments.

Turbine-end and generator-end couplings had minor rust and pitting on the faces and outside diameters, and numerous coupling holes showed moderate galling. MD&A would remove the galling to prepare for proper on-site reassembly. The generator end rabbet fit was peened and machined to maintain diameter and remove .002 in. runout when operating on both journals.

The two journals, T5 and T6, had moderate surface rust, pitting, radial scoring, and between .002” and .004” taper. Both were machined to remove the taper and damaged material, and oil seal lands were strap lapped.

Buckets

All rotor rotating stages had varying degrees of pitting and foreign-object damage on buckets and covers, including the outside of the roots and tenons. Magnetic particle NDE was performed on the rotor, liquid penetrant NDE was performed on the L-1 titanium notch buckets, and phased array ultrasonic NDE was performed on the L-0 finger dovetail pins. NDE reports confirmed corrosion pitting on all stages but revealed no crack-like indications. Moderate to severe erosion was noted on the L-1 tenons and L-0 buckets.

Minor repairs were performed on stages 13 through 18. Leading and trailing edges were straightened and blended, and polishing removed foreign object damage.

Six buckets with severe tenon erosion were replaced on the stage 18 turbine end (TE), including the titanium notch blade. Stage 18 (L-1) TE and generator-end (GE) tenons were high-velocity oxygen fuel coated with chromium carbide to slow the progress of erosion.

At stage 19, the L-0 row, both the TE and GE buckets had heavy erosion on the discharge side of the leading edges. Due to the long lead time for bucket replacements, MD&A experts recommended annual, in-hood inspection of erosion while procuring new buckets for replacement at the next major outage.

Diaphragms

NDE (MT and PT) was performed on the diaphragms. Common to all was moderate pitting on the partitions, setback faces, appendages, horizontal joints, and diaphragm body.

Of highest concern was pitting on the partitions. This had created small holes near some trailing edges.

Also noted was a large amount of missing hardware. Several lower half diaphragms did not have support blocks, and no joint bolts were present for stages 13 or 19.

Stage 13, the first low-pressure stage, is a bolted assembly consisting of both the turbine-end and generator-end diaphragms. The heavily eroded appendage was weld repaired near the joint where damage was most severe. High spots from FOD were removed and trailing edges were hand-blended and straightened. Indications found on previous Inconel restorations were also repaired.

The base material of the stage 14 partitions had moderate to severe pitting on both the concave and convex sides, which was repaired. High spots from FOD were removed and trailing edges were blended and straightened. Four new support blocks and new keys were provided.

Stage 15 partitions had moderate erosion and pitting. Pitting near the thin trailing edges had created small holes. If not repaired, more holes would appear and pieces would liberate and move downstream. Major Stage 15 repairs, therefore, became critical. MD&A specialists repaired the trailing edges by cutting back to a minimum thickness of 0.125 in. and welding new partitions in place, hand-working to match the incoming profiles. A damaged root radial seal was also repaired. Support blocks and various screws and keys were provided.

Although not as severe, small holes were found near the trailing edges of stage 16, primarily near the corners. Stage 16 joint blades were more severely damaged. All affected areas were cut back and repaired with Inconel. The remaining blades were straightened.

At stages 17 and 18, there was moderate damage to the joint blades, causing trailing edge deformation and small tears. These were weld-repaired, as was all FOD.

MD&A straightened and weld-repaired damaged trailing edges and repaired all NDE indications at stage 19.

All damaged packing retaining pin holes were weld-repaired and extra stock was welded to the crush pins to be fit on-site, to expedite reassembly. Broken diaphragm key screws were replaced, and new keys were made to replace those missing.

Recommendations

After all the repairs were completed, a high-speed balance was performed on the LPB rotor. The rotor was cleaned and prepared for shipment.

MD&A analysts recommended that the site monitor any pitting on the rotor and diaphragms and any progression of tenon erosion. Major future repair to stage 14 diaphragms should be considered.

For the stage 19 L-0 buckets, annual in-hood erosion inspections should be performed until near-term replacement.

MD&A completed both analysis and repair of this spare LPB unit on schedule and returned the unit ready for full service.

MD&A experts focused on detailed analysis and needed repair while leaving the owner/operator with both near-term confidence and a long-term plan for reliable performance of this critical G2 design unit.

Call MD&A today for any turbine/generator repair at +1 (314) 880-3000 or use our Contact form.

The post Spare LPB Rotor and Diaphragm Repairs appeared first on MDA Turbines.

Factors like load demand, aging units, and financial pressures have created the need for reliable and long-lasting steam turbine solutions. Our steam turbine parts capture the potential of plant auxiliary systems and retain thermal performance, providing high-quality and cost-effective enhancement of turbine efficiency.

Why choose MD&A?

For over 40 years, our commitment to excellence has earned customer trust for all turbine-generator needs. We focus on delivering consistent quality and value with fast response, superior communications, and innovative solutions.

MD&A is easy to work with. We provide immediate access to expert help when you need it, where you need it. Around the corner or the globe, we ensure prompt, thorough communication, and follow-through. For every repair job, large or small, the speed and effectiveness of our response team are matched only by the depth and breadth of our engineering expertise.

Find out today why so many power generators use MD&A to maximize operational effectiveness.

1.     Steampath Components

To handle turbine outages, our Parts Division maintains a wide array of steampath components or turbine hardware. We include multiple turbine hardware items in our inventory and provide prompt inquiry responses. All components are manufactured to exact OEM specifications and tolerances.

2.     Stationary Components

We offer multiple types of stationary components for steam turbine units. Some of the Steam Turbine Parts in our stock include atmospheric relief diaphragms, oil deflectors, and seal rings, like inlet piping-related snout rings and bell seals. We also provide Stellite® weld repair for inlet pipes. Other products we carry include support shims, thrust plates, journal bearings, gibs, and pump bearings.

3.     Valve Components

One of our core parts offerings includes a complete line of valve components for all types of steam turbines. All components are manufactured to OEM specifications. We also provide reverse engineering services including engineered design modifications. The MD&A Parts Division can also provide Stellite® weld repair to different types of valve components.

4.     Main Stop Valve Upgrade

Many plant owners experience main stop valve stem erosion. MD&A’s Parts Division offers alternative solutions such as the Triplet Type Main Stop Valve Upgrade. This component significantly reduces erosion on the valve stem and skirt and ultimately reduces valve maintenance.

5.     Combined Cycle Valve Drop-in Solution

This solution combines the steam turbine valve wear parts into one pre-assembled set. This allows you to replace them more quickly and moves the repair work and detailed shop inspection of the outage critical path. Our experts will inspect, replace, or repair each Drop-in set at the shop to ensure it is capable to handle the next outage.

6.     Guardian® Packing

Our Parts Division offers the patented advanced design Guardian® packing ring. The Guardian® Packing rings maintain a positive radial seal during shutdown, turning gear, start-up, and unit operation. Positive radial sealing is a key component in unit efficiency.

7.     Vortex Shedder® Spill Strips

MD&A Parts Division offers the patented advanced design Vortex Shedder® spill strip. It uses an aerodynamic geometry to reduce the leakage flow while improving stage heat rate performance. The Vortex Shedder® improves stage efficiency, whether the steam path design is reaction-based, impulse-based, or hybrid.

8.     Conventional Packing & Spill Strips

MD&A is a premier manufacturer of conventional design seals for all types of steam turbines. We provide conventional design shaft packing, gland packing, honeycomb seals, spring back seals, J-strip, caulked-in seals, and diaphragm packing. We also manufacture to OEM specifications and tolerances.

9.     Custom Seal Installation

Our MD&A Parts Division is focused on providing high-quality and cost-effective new and refurbished steam turbine parts to our clients. Our patented products like the Guardian® packing rings and the Vortex Shedder® spills are all custom-installed by an MD&A Parts expert.

10.     Tapered Land Thrust

Our experts have the capabilities to design, repair, and manufacture tapered land thrust bearings. These are useful for troubleshooting the thrust bearing temperature. We also offer material upgrades, fixture profiling, and performance monitoring instrumentation.

11.     Elliptical Journal

We design, repair, and manufacture elliptical bearings to remove the steam whirl or oil whip side effects of your steam turbine. We also provide short cycle delivery, insulation mounting and spherical mounting restoration, and performance monitoring instrumentation.

12.     Tilt Pad Thrust

A tilt pad thrust bearing retrofit is a cost-effective solution when sole plate settling or other foundation changes have created poor alignment conditions. We offer clients predictable bump check shim sizing and complete assembly reconditioning. We also offer material upgrades, performance monitoring instrumentation, and short-cycle delivery.

13.     Bronze Seal Rings

Incorrect oil seal clearances can cause long-term and immediate operational issues in turbine-generators. We manufacture bronze seal rings to improve the long-term service life of tight oil sealing systems and ensure that the rub-induced vibrations are minimal.

14.     Oil Deflectors

MD&A Bearings, Seals & Hydraulics Division offers complete oil deflector reconditioning to assure the long-term integrity of a tight oil sealing system. Our inventory includes seal tooth material, dowels, steam painting/cleaning, and body bolt components.

15.     Tilt Pad Journal

One of the steampath turbine parts we offer is tilt pad journal bearing retrofits. A tilt pad journal is useful for managing the effects of steam whirl or oil whip conditions. We offer complete assembly, provide material upgrades, performance monitoring instrumentation, and short cycle delivery.

16.     Legacy Turbine Circuit Boards, Repairs & Service

MD&A Turbine and Generator Controls Division has over 500 Novatech circuits in power stations in the US. Power plant owners can use these specially designed cards as a replacement. We offer most circuit cards for MKII and MKI, and many other OEM turbine control cards as well.

17.     Fasteners

MD&A Parts Division can quickly and effectively respond to the need for any type of fastener for many types of steam turbines. Our inventory also includes various washers and nuts, useful for turbine-generator maintenance. Other items we carry include dowels, hex and castle nuts, lockplates, rivets, and many others.

18.     IBECS® System

Our proprietary IBECS® system incorporates many effective solutions to monitor the condition of power plant units. One can easily configure the HMI online as well. Our IBECS® system presents many useful services that assist our clients, like Full Data Server Capability and Network Deployment features.

19.     Steam Turbine Retrofits

We offer comprehensive reaction and impulse turbine retrofit packages for LP, IP, HIP, and HP turbine sections. Our clients can choose between multi-section or single retrofit packages.

20.     Mitsubishi Power Continuous Cover Blades /Long Blades

In collaboration with Mitsubishi Power, we can provide many new long blade design improvements. The CCB or Continuous Cover Blades are constructed using a mono-block blade structure which leaves fewer locations for corrosive deposits. This also makes them less susceptible to stress corrosion cracking.

Conclusion

Our team at MD&A is dedicated to providing efficient, high-quality, and cost-effective steam turbine part solutions to our customers. Our turbine parts upgrades can enhance turbine efficiency and last longer!  Talk to one of our experts today and discover all of the turbine-generator parts we offer.

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The post Steam Turbine Parts Solutions appeared first on MDA Turbines.