- Economic and User friendly turbine.
- Suitable for constant Steam Back Pressure even on Variable Steam Loads.
- Horizontally Split Casing.
- Separate Gearbox from Turbine.
- Replaceable Blades and Nozzles.
- Multi Arc Steam Admission.
- Advanced PLC Based and Standalone Control Panels.
- Robust and Sturdy turbine for continuous operation
Constructional Features BT 4 / 6 Turbines
TURBINE CASING
The turbine casing of this SINGLE STAGE turbine is split on horizontal center-line to facilitate easy inspection and removal of rotor without disturbing lower half of casing or steam pipelines. The bottom-half of the cylinder is secured at the exhaust end by center-line support mounted on the exhaust end stool. The Steam chest, SE / EE bearing pedestals and all governor gears are fitted on the bottom half turbine cylinder which enable the top half of turbine cylinder to be removed without disturbing the steam pipe work. Centre line support assists the precise alignment of turbine with the driven machine, and the axial thermal expansion of the turbine is accommodated by a flexible support at the steam end of the turbine.
TURBINE ROTOR AND BLADES
The rotor is a BUILT UP TYPE using alloy steel forging to be of stiff design i.e. first critical speed is well above any operating speed or over-speeds. The soundness of rotor is ensured using latest Ultrasonic testing techniques. The blades are made of alloy steel. Each blade is machined in one piece with its spacer root and is fixed in the grooves on periphery of the wheel. The outer ends of blades are connected by short lengths of shrouds riveted on. Each rotor is dynamically balanced to high degree of accuracy. This ensures the trouble free and smooth operation of rotor and a long life of bearings. The thrust bearing and emergency over-speed governor are provided on the non-drive end of the rotor shaft.
NOZZLES
Nozzles are accurately machined, segments are replaceable and designed for high efficiency out of stainless steel material to increase nozzle life.
HAND OPERATED STEAM NOZZLE VALVE
One hand-operated valve is fitted on the nozzle box to control the additional nozzles for higher loads or as a safeguard against low boiler steam pressure.
EMERGENCY OVERSPEED TRIP GEAR
The eccentric ring is mounted on the rotor shaft within the steam end pedestal and is held in concentricity with the shaft axis by a spring. When the turbine speed reaches approximately 10% above the normal, the centrifugal unbalance overcome the spring force and the ring flies out, striking the trip lever, which de-latch the trip rod. The butterfly emergency valve is then closed by its spring. Steel shims are provided inside the outer spring holder and spring for easy adjustment of the tripping speed.
SPEED GOVERNOR
It is a self-contained hydraulic unit of reputed make driven from the turbine rotor shaft through a set of gears.
STEAM GLANDS
These are segmental carbon ring types with three segments per ring. Each ring is held together with a spring.
OIL BAFFLES
The turbine bearings adjacent to the steam glands are provided with oil baffles to prevent leakage of lubricating oil from the bearing housing. Also in association with the throwers on the rotor shaft, these oil baffles discourage any steam from entering the bearing housings and contaminating the oil thus keeping the oil free from water.
EXHAUST PRESSURE WARNING VALVE
To give warning of excessive exhaust steam pressure, an exhaust warning valve is provided. This is a simple spring-loaded valve located on the top of the exhaust casing of the turbine. The valve is set to exhaust at a steam pressure above by 10% from the normal exhaust pressure.
BASEPLATE
This is of fabricated construction and has a built-in oil reservoir. An oil level indicator is fitted. The base-plate is secured with the foundation by special bolts.
GEAR COUPLING
A gear coupling is fitted to couple the alternator shaft with the output shaft of the bull gear. This coupling must be filled with Greece before starting the turbo set and also periodically during operation.
SPEED REDUCTION GEAR
Speed-reducing gear is generally mounted on the turbine base-plate. The high-speed gears are precision-machined, hardened and ground to achieve long operating-life. Lubricating oil from the lubricating oil system is used for cooling of the gears. The main oil-pump is mounted on the free end of the low-speed gear.
- Up to 5 Stages for High Efficiency.
- Bleed Provision for different back pressure outlets.
- Programmable Control Panel for Synchronized and Standalone operation.
- Woodward Governor for accurate control.
- Robust and Sturdy turbine for continuous operation.
MBT-6 Multi Stage Back Pressure Steam Turbines with Extraction
TURBINE CASING
The turbine casing of this MULTI-STAGE turbine is split on horizontal center-line to facilitate easy inspection and assembly during maintenance. Proper tightness of the mating surfaces is ensured through high-accuracy finish and using metal-to-metal contact without any sealing compound. The bottom half high pressure end of casing is secured and supported by a kinematic support to allow controlled expansion between casing and bearing pedestal. Radial pins fitted between casing flange and bearing pedestal, permit radial expansion of casing maintaining its concentricity with the pedestal which in turns ensures correct alignment during operation. A gap between the casing and the bearing pedestal allows for free circulation of air thus minimizes the transfer of heat between from hot casing to the bearing pedestal.
TURBINE ROTOR AND BLADES
The rotor is a solid alloy steel forging and designed to be of stiff; i.e. the first critical speed is well above any operating speed or over-speeds. The soundness of the rotor is ensured using latest Ultrasonic testing techniques. The blades are made of alloy steel. Each blade is machined in one piece with its spacer root and is fixed in the grooves on periphery of the wheel. The outer ends of blades are connected by short lengths of shrouds riveted on. Each rotor is dynamically balanced to high degree of accuracy. This ensures the trouble free and smooth operation of rotor and a long life of bearings.
COMBINED STOP AND EMERGENCY VALVE, CONTROL VALVE
The stop-and-emergency valve is spring loaded. The whole steam flow to the turbine passes first through the single beat combined stop and emergency valve, and then through the double seated control valve to the first stage nozzles of the turbine. The stop and emergency valve is mounted horizontally for ease of operation. The valve held fully open by the latch. Under the emergency conditions determined by the emergency trip gear and solenoid valve, the trip latch is operated and the Valve is closed by the action of valve spring. The valve when tripped is shut. Turning the hand wheel clockwise moves the guide nut, compressing the valve spring and keeping the valve on its seat. As the guide nut reaches the end of its travel, the trip catch is automatically engaged and is locked. Turning the hand wheel in ANTI-CLOCK direction, valve may then be opened.
The Combined stop and Emergency Valve incorporates a balanced main valve and a pilot valve to enable it to be freely opened or closed against the full steam pressure, except when the valve is close, steam may pass through the holes in the main valve to equalize the pressure on either side of the valve. However, when the Combined Stop and Emergency valve is shut, the pilot valve having a small sliding movement relative to the main valve closes these holes.
The control valve is mounted in the steam chest, which is rigidly bolted to the bottom half of the turbine cylinder. Depending on the load on the turbine, the control valve is opened by the linkage from the speed governor.
A steam strainer is provided on the inlet side of the valve to protect the turbine from the ingress of foreign matter.
BEARINGS
The rotor is supported at both ends with special designed white-metal lined journal bearings called OFF SET HALF type. The bearing at the steam end side is housed in the pedestal attached with the turbine cylinder with a special attachment.
A tilting pad type thrust bearing also contained in this bearing pedestal, which locates the rotor in its correct position and carries axial load developed during operation. The exhaust end bearing is fitted in a housing formed at the exhaust end of the turbine cylinder.
NOZZLES AND DIAPHRAGMS
The nozzle blades are secured to the steam belt formed at the steam end of the turbine cylinder and may be divided in Maximum three sections depending on the individual contract requirement.
Inter-stage diaphragms with nozzles are mounted in grooves in the casing. These diaphragms are supported on radial copper crushing pins, which are fitted to give the correct vertical location of the diaphragm.
Transverse location of the diaphragm is maintained in a similar manner by stainless steel side pins in the upstream side of the diaphragm. The top half diaphragms are further secured with help of Check screws at the horizontal face.
SPEED REDUCTION GEAR
Speed-reducing gear is generally mounted on the turbine base-plate. The high-speed gears are precision-machined, hardened and ground to achieve long operating-life. Lubricating oil from the lubricating oil system is used for cooling of the gears. The main oil-pump is mounted on the free end of the low-speed gear.
GLAND SEALS
Metallic LABYRINTH type glands seal the passage of the rotor shaft through the turbine cylinder. These are formed by group of knife-edged spring loaded NICKEL LEADED BRONZE rings and mounted in segments in annular grooves in the gland housings and also inter-stage diaphragms. The baffles are able to move radially on contact with the shaft to provide protection against rubs and bending of the rotor. These are having radial clearances with the rotor shaft.
These form series of multiple throttling, which reduces the pressure, and minimize the leakage of steam along the shaft. Spaces are arranged between the groups of baffle rings at the steam end and exhaust end of the turbine. The high-pressure end first leak off is led to the exhaust branch. The remaining two H.P. leak offs and the two L. P. leak offs are led to terminal flanges, which also receive the leak-off steam from the valve spindles of emergency and control valve.
OIL BAFFLES
The turbine bearings adjacent to the steam glands are provided with oil baffles. In addition to preventing the escaping of lubricating oil from the bearing housing these baffles, in association with the steam ejector, also minimize the chances of any steam or moisture-laden air entering the bearing housing thus avoiding contamination of oil. In this way, the greatest difficulty of turbine maintenance is avoided.
SPEED GOVERNOR
The speed governor is Hydro Mechanical type as standard scope of supply. This governor takes its drive from the turbine rotor shaft through a train of worm and worm wheel. The link rod attaches the output of the governor to the steam control valve. The governor has a provision for speed droop adjustment and motorized gear to operate from a remote position.
EMERGENCY OVERSPEED TRIP GEAR
The eccentric ring is mounted on the rotor shaft within the steam end pedestal and is held in concentricity with the shaft axis by a spring. When the turbine speed reaches approximately 10% above the normal, the centrifugal unbalance overcome the spring force and the ring flies out, striking the trip lever, which de-latch the trip rod. The emergency valve is then closed by its spring. The emergency trip gear may also be operated manually or by the solenoid trip valve, which is associated with the protection system for the unit.
LUBRICATING OIL SYSTEM
Lubricating main oil for the turbo set is provided from the geared type oil pump driven from the free end of bull gear shaft of the reduction gear box through a flexible coupling. An auxiliary A.C. motor driven geared oil pump is also provided for flooding the bearings before starting and for maintaining an adequate supply of oil while running up and shutting down. The operation of A.C. motor driven pump is made automatic by providing a pressure switch in the lubricating oil system. Non-return valves on the delivery lines of auxiliary pump and main oil pump prevent the performance of auxiliary pump by the discharge of the main oil pump. The lubricating oil is water cooled through the oil cooler. A fine filter is provided in the oil system to avoid any foreign material flowing to the bearings.
LOW OIL PRESSURE TRIP
Its purpose is to protect the turbine from damage, which might be caused by low oil pressure. The trip consists of a hydraulic piston and cylinder. In running conditions the lube oil pressure held the valve in position and if oil pressure falls to a value 0.5-0.7 kg/cm2 this pressure is incapable of holding the valve against the spring load, thus activating the tripping system.
BASEPLATE
This is of fabricated construction and has a built-in oil reservoir. An oil level indicator is fitted. The base-plate is secured with the foundation by special bolts.
- Upto 9 Stages for High efficiency
- Horizontally and Vertically Split Casing
- Separate Gearbox from Turbine
- Water Cooled Condenser with multi effect Vacuum system.
- Woodward Governor for accurate control.
- Robust and Sturdy turbine for continuous operation.
BCT-6 Multi Stage Condensing Turbine with Extraction
TURBINE CASING
The turbine casing of this MULTI-STAGE turbine is split on horizontal center-line to facilitate easy inspection and assembly during maintenance. The casing is split on the horizontal center-line to allow for easy inspection. The bottom half of the turbine casing is secured on 4 stools through clearance bolts and keys which allow thermal expansions in desired manner.
The bottom half steam end bearing pedestal is secured with casing by a kinematic support to allow controlled expansion between casing and bearing pedestal. Radial pins fitted between casing flange and bearing pedestal, permit radial expansion of casing maintaining its concentricity with the pedestal which in turns ensures correct alignment during operation. A gap between the casing and the bearing pedestal allows for free circulation of air thus minimizes the transfer of heat between from hot casing to the bearing pedestal.
TURBINE ROTOR AND BLADES
The rotor is a solid alloy steel forging and designed to be of stiff; i.e. the first critical speed is well above any operating speed or over-speeds. The soundness of the rotor is ensured using latest Ultrasonic testing techniques.
The blades are made of alloy steel. Each blade is machined in one piece with its spacer root and is fixed in the grooves on periphery of the wheel. The outer ends of blades are connected by short lengths of shrouds riveted on.
Each rotor is dynamically balanced to high degree of accuracy. This ensures the trouble free and smooth operation of rotor and a long life of bearings.
COMBINED STOP AND EMERGENCY VALVE, CONTROL VALVE
The stop-and-emergency valve is spring loaded. The whole steam flow to the turbine passes first through the single beat combined stop and emergency valve, and then through the double seated control valve to the first stage nozzles of the turbine. The stop and emergency valve is mounted horizontally for ease of operation. The valve held fully open by the latch. Under the emergency conditions determined by the emergency trip gear and solenoid valve, the trip latch is operated and the Valve is closed by the action of valve spring. The valve when tripped is shut. Turning the hand wheel clockwise moves the guide nut, compressing the valve spring and keeping the valve on its seat. As the guide nut reaches the end of its travel, the trip catch is automatically engaged and is locked. Turning the hand wheel in ANTI-CLOCK direction, valve may then be opened.
The Combined stop and Emergency Valve incorporates a balanced main valve and a pilot valve to enable it to be freely opened or closed against the full steam pressure, except when the valve is close, steam may pass through the holes in the main valve to equalize the pressure on either side of the valve. However, when the Combined Stop and Emergency valve is shut, the pilot valve having a small sliding movement relative to the main valve closes these holes.
Steam, after passing through the emergency valve, flows to the turbine through balanced double-seated control valve. The control valve is mounted in the steam chest, which is rigidly bolted to the bottom half of the turbine cylinder. Depending on the load on the turbine, the control valve is opened by the linkage from the speed governor.
A steam strainer is provided on the inlet side of the valve to protect the turbine from the ingress of foreign matter.
BEARINGS
A white metal lined journal bearing supports the rotor at each end. The bearing at the high-pressure end is housed within the steam end pedestal, and the exhaust end bearing is contained in the exhaust end cylinder.
A tilting pads type thrust bearing contained in the high- pressure end bearing housing, is provided to locate the rotor in its correct position and to carry any axial thrusts developed. A reverse thrust bearing carries any temporary reverse thrust, such as may occur when the turbine is being started or stopped.
NOZZLES AND DIAPHRAGMS
The nozzle blocks are bolted to the steam belt formed at the steam end of the turbine casing. The inter-stage diaphragms are mounted in grooves in the turbine cylinder.
Check screws retain the top half diaphragms. Radial crushing pegs are mounted at intervals round the rims of the top and bottom half diaphragms. The crushing pegs, by compression, accommodate any differences in expansion between the turbine cylinder and the diaphragms, and also provide support when the top half cylinder is turned over during maintenance.
For ease in fitting and ease of removal, the diaphragms are fitted with side pegs located at intervals round the inlet faces of the diaphragms.
A key is provided along each diaphragm joint, sunk half its depth in each half diaphragm to minimize steam leakage, the keys being secured to the bottom half diaphragm joint faces by retaining screws.
The spaces are arranged between the groups of baffle rings at the high-pressure and low-pressure ends of the turbine for leaking off steam.
MOISTURE EXCLUDING OIL BAFFLES
The turbine bearings adjacent to the shaft glands are provided with moisture-excluding oil baffles.
In addition to preventing the lubricating oil from escaping from the bearing housings, these baffles also prevent any steam or moisture-laden air from entering the bearing housings and contaminating the oil. In this way, the oil is kept free from water and one of the greatest difficulties of turbine maintenance is avoided.
SPEED CONTROL
Speed control and emergency over speed governors are provided. The Woodward UG40 type speed control governor controls the opening of the steam control valve, in order to maintain a substantially constant speed irrespective of the load on the turbine. The emergency trip gear protects the turbine in the event of a failure of the normal speed governor by closing the independent emergency valve and completely shutting off the steam supply to the turbine, if the turbine speed exceeds the normal running speed by 10 - 12 percent.
The emergency trip gear may also be operated manually or by the solenoid trip valve, which is associated with the protection system for the unit.
GLAND SEALING SYSTEM
Metallic LABYRINTH type glands seal the passage of the rotor shaft through the turbine cylinder. Spaces are arranged between the sets of labyrinth gland rings for leaking off steam. This is led to the turbine exhaust and to atmospheric leak-off pipes. An arrangement referred to as "Leak-off sealing" is used in which leak-off steam from the high pressure gland is used to seal the low pressure gland, and thereby prevent the leakage of air into the turbine and hence into the condenser. A separate supply of sealing steam is also provided to seal the glands for starting and for cases when the pressure in the first stage is so small that there would be insufficient steam leaking off from the high-pressure gland to seal the low-pressure gland. When the turbine is running on load, adjustments of supply of leak-off steam to the low-pressure gland are effected by adjusting the regulating valves, which control the flow of steam from the H.P. to the L.P. gland.
LUBRICATING OIL SYSTEM
Lubricating oil for the unit is provided from a main oil pump driven from the bull gear shaft of the reduction gearbox. An auxiliary motor driven oil pump is also provided for flooding the bearings before starting and for maintaining an adequate supply while running up and shutting down. A low lubricating oil pressure trip device is fitted to initiate a turbine shutdown in the event of the low lubricating oil pressure. This arrangement also ensures that the bearings are flooded before the turbine can be started. It is not intended that the turbine should run on the auxiliary oil pump. A non-return valve on the outlet of the pump prevents the auxiliary oil pump being affected by the discharge from the main oil pump. The lubricating oil is water cooled through the oil cooler. A fine filter is provided in the oil system to avoid any foreign material flowing to the bearings.
SPEED REDUCTION GEAR
Speed-reducing gear is generally mounted on the turbine base-plate. The high-speed gears are precision-machined, hardened and ground to achieve long operating-life. Lubricating oil from the lubricating oil system is used for cooling of the gears. The main oil-pump is mounted on the free end of the low-speed gear.
LOW OIL PRESSURE TRIP
Its purpose is to protect the turbine from damage, which might be caused by low oil pressure.
The trip consists of a hydraulic piston and cylinder. In running conditions the lube oil pressure held the valve in position and if oil pressure falls to a value 0.5-0.7 kg/cm2 this pressure is incapable of holding the valve against the spring load, thus activating the tripping system.
HIGH SPEED AND SLOW SPEED COUPLINGS
To accommodate differential expansion (i.e. the relative growth of several elements subject to differing temperatures) and to maintain correct meshing of gear teeth under all conditions an all metallic spacer type flexible coupling is provided between the turbine and the pinion shaft. A flexible gear coupling / spacer coupling is provided between the gear bull shaft and the alternator shaft.
BASEPLATE
This is of fabricated construction and has a built-in oil reservoir. An oil level indicator is fitted. The base-plate is secured with the foundation by special bolts.
Imparting additional strength. For larger blades like in low-pressure condensing stages, damping wire is provided. Special care is given to the stress analysis.
NOZZLES
Nozzles are manufactured from stainless steel. The first-stage nozzles are fixed into groove in the casing / nozzle chest and welded (for high-pressure applications). The nozzles, for subsequent stages, are fitted / welded into diaphragms, which are then fixed into grooves located between the stages. These diaphragms split near the horizontal center-line, for easy removal and maintenance.
GLAND SEALS
The gland seals generally used are metallic labyrinth-packing for external gland-seals (where rotor comes out of the casings), as well as, for inter-stage gland-seals. The length of external labyrinth-packing depends upon the level of turbine exhaust-pressure.
- Low Speed, No Gearbox
- Generates Power based on Steam Flow
- Maintains Constant Back Pressure
- Horizontally Split Casing, Easy maintenance.
- Electronically Controlled thru PLC
- Grid Synchronized, meets Steam Flow Variations.
PRT-6 SATURATED STEAM PRESSURE REDUCING TURBINE
OPTIMIZED BY ANALYSIS
Optimized blade condition for both design and off- design conditions, because we understand your demands, not the other way round. Finite Element Analysis, CFD analysis, thermal analysis, Rotor dynamic balancing, Torsional analysis, Axial Thrust analysis, vibrational analysis done for every row of nozzles and blades, ensuring maximum safety and efficiency.
MANUFACTURED WITH UTMOST PRECISION
All blades are manufactured out of high grade materials, using CNC machining. Minimum manufacturing tolerances, which means we match the result we commit to.
COMPLETE ELECTRONIC GOVERNING
Fully synchronized with grid. No Mechanical Governor, ensuring complete electrical control over your machine by PLCs.
ZERO DELIVERY TIME
Available off the shelf , ensuring you start getting returns immediately.
MINIMUM INSTALLATION TIME
Skid mounted Turbine and Generator, ensuring minimum erection time, allowing you to start operations in a matter of days.
VISIBLE RESULTS
Units of electricity generated and savings incurred can be seen at any time on the Panel.
BRISK SERVICE
Horizontally split casing, ensuring quick service in a few hours. Separate casing for turbine, ensuring quick inspection and rectification.