Turbine Blades

MD&A has joined with Hitachi to introduce major improvements in long blade design to the US market. These long blades are constructed using a mono-block blade structure that leaves fewer locations for corrosive deposits and are less susceptible to stress corrosion cracking. Reliability is enhanced by simple connections at the blade tip that consists of a Hitachi's advanced Continuous Cover Blade. All blades are installed by seasoned technicians and installation is supervised by highly experienced MD&A steampath engineers.

Hitachi's advanced Continuous Cover Blade (CCB) offers:

• High Reliability
• Mono-block blade structure
• Fewer locations for corrosive deposits
• Less susceptible to stress corrosion cracking
• Interlocking integral covers- eliminates tenons & cover to tip closing issues
• Simple connections at blade tip & mid-span locations
• Reduced stress levels
• Elimination of stress concentration points at the tie-wire hole locations

Current Blade Sizes Available

• 23" L-0, Coming soon
• 26" L-0, 14.414", L-1, 16.59" L-1
• 30" L-0, 17", L-1
• 33.5" L-0, 20.9" L-1

Steady Stress Analysis Results

• Significantly reduced stress in the blade profile
• Elimination of tie-wire holes

Excellent Vibration Characteristics

• Predictable sinusoidal mode form
• Dampening from integral locking cover
• Fewer resonance points, easier de-tuning

Improved Efficiency

• Up to an 8% stage efficiency increase on the 26" LSB without a new diaphragm
• Advanced transonic blade profile
• Elimination of tie-wires on vanes up to 26"
• 26" blades covered for improved steam flow

Drop-in Replacement

• No need to replace diaphragms or modify existing components

Increased Back-pressure Limits

• Alarm at 7" and trip at 9.6" Hg on 26" blades

Proven Operating results & Experience

• Over 12 rows installed by MD&A on rotors manufactured by the General Electric Company
• 26" LSB first installed in 1991
• Over 93 rows in service by 2001

For more information about Hitachi's advanced Continuous Cover Blades (CCB) and other steampath services please contact our Steampath Engineering Services division at (518) 399-3616.