Steam Turbine Spare Parts

Steam Turbine Components (Reference: instrumentationtools.com)

The industrial process heavily relies on steam turbines. If they fail, productivity is hampered. Your steam turbines require acceptable spare parts of OEM quality, yet original parts are frequently quite expensive. In this article, we'll look at the characteristics of each steam turbine component.

Steam Turbine Spare Parts

The core components of all steam turbines are the same, however their arrangement varies greatly. Each steam turbine's components are divided into 9 groups, as below:

1.) Turbine casing (HP, LP and IP Turbine Casing)

2.) Anchor Points of Turbine

3.) Rotor (HP, IP and LP Turbine)

4.) Blades

5.) Bearings & Bearing Pedestal

6.) Sealing system (Gland Seal, Steam System)

7.) barring gear

8.) Coupling

9.) ESV’s, IV’s and CV’s

Each of these components has a distinct purpose, and when combined with the others, they result in the final functioning and ultimate objective of the steam turbine, which is the generation of power and kinetic energy. You can visit Steam Turbine Equipment in Linquip to get further information on this equipment. In the following section, you will learn about each of these components and how they work in steam turbines.

Linquip has a variety of Steam Turbine Suppliers and Companies that can supply you any steam turbine part based on their decades of experience and re-engineering capabilities. With the use of the most recent verified tools, they can produce and deliver spare parts for industrial turbines with enhanced features and materials for improved performance. It is recommended that you also visit the List of Steam Turbine Distributors in Linquip.

1) Turbine Casings

HP Turbine Casing:

• Barrel-shaped outer casing without an axial or radial flange.
• Casing of the barrel type is ideal for rapid startup and loading.
• The inner casing— cylindrical , axially split.
• The inner casing is linked to the barrel casing in the horizontal and vertical planes, allowing it to freely expand radially in all directions and axially from a fixed point (HP-inlet side).
  
  

IP Turbine Casing:

• The IP turbine's casing is made of two shells that are split horizontally.
• Both are axially divided, and a double flow inner casing that contains the guide blades is supported by the outer casing.
• offers compensated axial thrust and opposing double flow in the two blade portions.
• Steam enters the inner casing from the top and bottom after reheating.
  
  

LP Turbine Casing:

The triple shell welded casing of the LP turbine is composed of a double flow unit:

• The shells are rigidly welded and are axially split.
• The inner shell, which contains the first rows of guide blades, is kinematically linked to the middle shell.
• The middle shell, which is independent of the outer shell, is supported at four points on longitudinal beams.
• Steam allowed to the LP turbine from the IP turbine flows into the inner casing from both sides.
  
  

A typical HP-IP steam turbine (Reference: powermag.com)

2) Anchor Point of Turbine

The purpose of this is to protect the machine against thermal expansions and contractions during thermal cycling.

The following are the turbine's fixed points:

• The bearing housing between the IP and LP turbines.
• The rear bearing housing of the IP turbine.
• The longitudinal beam of the I.P turbine.
• The thrust bearing in the rear bearing casing of H.P turbine.

3) Rotors

HP Rotor:

• The HP rotor has integrated discs and is machined from a single Cr-Mo-V steel forging.
• Balancing holes are machined into all of the moving wheels to reduce the pressure differential across them, which lowers the axial thrust.
• The first stage features integrated shrouds, whereas the other rows have shroudings that are perimeter riveted to the blades.
  
  

IP Rotor:

• The IP rotor has seven discs that are integrally forged with the rotor, with the remaining four discs being shrink fit.
• The shrunk fit disc is machined from high strength nickel steel forgings, while the shaft is composed of high creep resistance Cr-Mo-V steel forging.
• All wheels have shrouding riveted at the blade tip, with the exception of the final two. In certain stages, lashing wires have been installed to allow the frequency of the moving blades to be adjusted.
  
  

LP Rotor:

• The LP rotor is made up of shrunk-fit discs and a shaft.
• The discs are high strength nickel steel forgings, whilst the shaft is made of forgings of Cr-Mo-V steel.
• With the help of riveted fork root fastening, blades are secured to the corresponding discs.
• Wire lashings are available at every stage to modify the frequency of the blades. The leading edges of the blades in the last two rows have satellite strips installed to guard against wet steam erosion.

4) Blades

• most expensive component of a turbine.
• Guide blades/nozzles are blades attached to stationary parts, and rotating/working blades are blades attached to moving parts.
• The three primary components of a blade are: Aerofoil (functional part), Root, Shrouds.
• Shrouds are used to direct steam to the following set of rotating blades and to stop steam leakage.
• Three different root configurations are frequently utilized. For smaller blades, there are T-roots; for longer blades, there are Fir Tree or serrated roots; and for longer blades shrunk on disc-style rotors, there are Fork and Pin roots.
• For shorter blades, integral shrouds are employed, while for longer blades, shrunk fittings.
• Lacing wires are also used to balance the frequencies in the longer blades and to reduce vibration.
• Effective sealing at the blade tips are required since the pressure drop in the response type machine also happens throughout the rotating blades.
  
  

Steam Turbine Blades (Reference: allindustrialtraining.com)

5) Bearings

Bearings are typically forcibly lubricated and include provisions for jacking oil entry.

A) Front Bearing Pedestal: This is positioned on the turbine side of the turbine generating unit. Its job is to carry the turbine rotor and support the turbine casing. It includes the below components:

a. Journal bearing

b. Hydraulic turning gear

c. Electric speed transducer

d. Main oil pump with hydraulic speed transducer

e. Over speed trip

f. Shaft vibration pick-up

g. Bearing pedestal vibration pick-up

B) HP Rear Bearing Pedestal: Between the HP and IP turbines is where the bearing pedestal is situated. Its job is to carry the HP IP rotor and support the turbine casing. It contains the following elements

a. Combine Journal and Thrust bearing

b. Shaft vibration pick-up

c. Bearing pedestal vibration pick-up

d.Thrust Bearing trip (electrical)

C) IP Rear Bearing Pedestal: Between the HP and IP turbines is where the bearing pedestal is situated. Its job is to carry the HP and IP turbine rotors and support the turbine casing. The following turbine parts are housed in the bearing pedestal:

a. Journal bearing

b. Shaft vibration pick-up

c. Bearing pedestal vibration pick-up

d. Hand barring arrangement

f. Differential expansion measurement device

D) LP Rear Bearing Pedestal: The bearing pedestal is located between the LP turbine and generator. Its role is to support the LP rotor. This contains the following turbine components:

a. Journal bearing

b. Shaft vibration pick-up

c. Bearing pedestal vibration pick-up

6) Sealing Glands

• Steam is fed to the sealing chamber at 1.03 to 1.05 Kg/sq.cm abs and 130 deg.C to 150 deg.C from the header.
• With the aid of a unique steam ejector, air steam mixture from the final sealing chamber is drawn into the gland steam cooler.
• When the rotor contracts during a trip or a sharp load decreases, a provision has been created to deliver live steam at the front sealing of the HP and I.P. rotor to control the differential expansion

7) Barring Gear

• The major function of barring gear is to slowly and constantly rotate the turbo generator rotors.
• Begins shaft rotation during a starting period before to steam injection into the steam turbine
• The double row blade wheel that rotates the shaft system is powered by oil provided by AOP.
• Barring speed is 210/240 rpm.

8) Couplings

Due to forging limitations and other technological and economic factors, shafts are fabricated in small parts, necessitating connection between any two rotors.

9) ESV & CV

• Two primary stop valves and two control valves are symmetrically placed. The main steam enters the system via the main steam intake, passing via the main stop valves and then the control valves. Steam travels from the control valves to the turbine casing.
• The turbine has an emergency stop valve that cuts off the steam supply, as well as control valves that regulate the steam supply.
• Servo motors that are under the supervision of a protective system control emergency stop valves.
• To control the supply of steam, control valves are activated by the regulating system using servo motors.