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EL-type Pulverizer Rebuild Services

ALSTOM applies its years of experience in the engineering and design of coal pulverizers in providing components and services for EL-type pulverizers.

1. Yoke Repairs

2. Air Seal Repairs

3. Rotating Assembly Rebuilds and Repairs

4. Spring Bolt Rebuilds

5. Bearing Plate Repairs

6. Gear Case Repairs

7. Pinion Repairs

8. Gearbox Overhauls

1. YOKE REPAIRS

The Yokes in an EL-type mill take a beating, but fortunately, they are repairable and rarely need replacement. Alstom reconditions all yoke sizes and styles. Alstom weld repairs, hard surfaces, machines and re-bushes the yoke back to as new condition.

Repair Scope

• Basic Service
• Disassemble
• Blast to clean
• Dimensionally and NDT inspect
• Based on inspection additional services can include:
• Weld up worn areas as required
• Weld up bushing bores
• Wear protect (hardface) high wear areas
• Tap wedge ring holes
• Machine wedge ring area
• Machine grinding ring seating surface
• Install new yoke bushing and drive pin

2. AIR SEAL REPAIRS

Air seals are critical to contain the hot primary air within the mill and prevent dusty hot air from contaminating the mill gearbox. They also reduce heat transfer into the gearbox. If your gearbox oil is running hot or contaminated, the air seal may need replacement and repair.

Alstom can repair the air seal for the EL 64, 70 and 76 mills with new bronze inserts saving substantial cost over replacement. If the top of the air seal is worn or damaged, Alstom can cut off the damage and weld in a new seal carrier and save the housing.

Repair Scope

• Basic Service
• Disassemble
• Blast to clean
• Dimensionally inspect
• Based on inspection additional services can include:
• Remove old seals
• Weld up air seal area as required
• Replace seal carrier if necessary
• Machine to accept new bronze labyrinth seals
• Install new seals
• Install new air pipe(s)

3. ROTATING ASSEMBLIES

The mill rebuild schedule is tight and you are worried about blue fitting the yoke and gear center in an uncontrolled environment. It has to be done correctly for long shaft life and reliability, but the schedule must be met. A ready to run rotating assembly is the answer. Alstom will inspect, repair and rebuild your spare yoke, gear center and other parts or supply new ones. A new high quality shaft will be made and fit blue to the yoke and gear center. Run outs of the mounting faces are checked and cut if needed.

Available for EL 64, 70 and EL 76 Rotor Assemblies

Rebuild Scope

• Basic Service
• Disassemble
• Clean
• Dimensionally inspect
• Based on inspection additional services can include:
• NDT yoke and gear center for cracks
• Weld repair/Machine yoke, and install new yoke bushing and drive pin
• New main shaft – See 'Alstom upgraded keyless main shaft option'
• New SuperNut upgrade – See 'Alstom upgraded keyless main shaft option'
• Blue fit gear center to main shaft
• Blue fit yoke to main shaft
• Machine yoke seating surface and gear center as required
• Document blue fit with photos and inspection documents

4. SPRING BOLT REPAIRS

Alstom can rebuild your EL 64, 70, and 76 Mill size Spring Bolt assemblies.

Rebuild Scope

• Basic Service
• Disassemble
• Clean
• Dimensionally inspect
• Based on inspection additional services can include:
• Repair housing
• Replace key
• Recondition retaining ring
• Replace nut and adjusting bolt and hardware
• Paint
• Fill with grease

5. BEARING PLATE REPAIRS

Bearing Plates wear from rejects rubbing on the top surface. Usually, Bearing Plates are repaired using inserts to replace the worn material. In rare cases, a Bearing Plates is damaged beyond repair and a new one is required. Alstom offers the original cast iron material and an improved steel Bearing Plate for popular mill and shaft sizes.

Repair Scope

• Basic Service
• Disassemble
• Blast Clean
• Dimensionally and NDT inspect
• Based on inspection additional services can include:
• Clean Tapped holes
• Prime, Paint/cosmolene protect
• Sleeve bore
• Machine flat top and bottom mounting services
• Replace seal and cover rim area
• Replace seal and cover floor area
• Replace seal, cover, floor and air seal mounting surface

6. GEAR CASE REPAIRS

Replacement of the EL gear case with a new component can be a very expensive and lead time intensive task. While Alstom can supply new gear casings, we have developed a rebuild process for restoring EL gear cases to original specifications without compromising the quality or structural integrity of the component.

Rebuild Scope

• Basic Service
• Blast Clean
• Dimensionally inspect
• Based on inspection additional services can include:
• Sleeve bearing bore if necessary
• Re-machine bearing and oil pump pedestal as required
• Re-machine upper flange area and pedestal, parallel and to original dimension
• Paint inside cast surfaces with gearbox sealer
• Paint outside, non-machined surfaces,
• of gear case with high temperature paint
• Final inspect gear case
• Cosmoline protect machined surfaces to prevent rust

7. PINION REPAIRS

Alstom power has the capability of rebuilding your EL 64, 70 and EL 76 Pinion Assemblies. The Pinion Assemblies can be rebuilt individually or as a sub-component of the lower half of the EL mill.

Rebuild Scope

• Basic Service - Pinion Housing & Assembly
• Disassemble
• Clean
• Inspect
• Based on inspection additional services can include:
• Pinion Housing
• Re-machine housing ends
• Cosmolene Protect
• Pinion Assembly
• Dimensionally record bores and shaft diameters
• NDT shaft and pinion gear
• Replace bearings and packing
• Reassemble/Cosmolene Protect

8. GEARBOX OVERHAULS

The EL-type gearbox is a well designed, and built machine. It will provide decades of reliable service when properly assembled, maintained and operated. The bearings and gears have very high calculated lives and design factors. The time between rebuilds depends mostly on operation. A properly loaded mill will run much longer than low or dry operation. Foreign material causes high shock loads that can damage the gearbox and shorten its life.

Alstom has all the parts and services to put the gearbox back to original condition or improve the equipment for today's demands.

Alstom has the capability of rebuilding the full lower half of the EL mill as a single unit or the individual sub-components depending on the customer preference.

Rebuild Scope

• Basic Service
• Disassemble
• Clean
• Inspect
• Based on inspection additional services can include:
• Replacement parts such as gears, bearings, shafts, seals
• Rebuild to as-new conditions
• Rebuilt gearboxes
• Fleet rebuild programs
• Rental agreements
• Purchase options