A high pressure steam turbine having a sealing gland where the turbine rotor penetrates the casing of the turbine. Us4541247a steam turbine gland seal control system. Hydraulic control systems in gas and steam turbines. This tutorial provides an overview on large steam turbines systems and their auxiliaries in oil and gas applications from a contractor perspective. Gland sealing, control oil, seal oil, lubricating oil. A control system is provided to modify the temperature of the auxiliary steam to be more compatible with the self sealing steam, so as to eliminate thermal shock to the turbine rotor. In section 1, steam turbine operating conditions are described including the steam cycle, the chemical control of the steam water circuit and the distribution of temperature, pressure and steam wetness in the turbine.
Turbine gland steam condenser valve control theory free. Since the exhaust steam is led to the vacuum condenser, the coupling end gland creates a vacuum. Some of the advantages found in the dry gas seal over the conventional carbon ring bushing are as follows. Labyrinth packing an overview sciencedirect topics. Thus for a gland with a given number of restrictions, there is an associated pressure ratio that produces the maximum leakage through the gland.
Service experience indicates that cracking occurs mainly in regions where condensates form. Steam turbinegenerator overhaul and inspection guidelines. Turbine gland seal steam control valves valve engineering. The valves installed for turbine control are designed and built by the turbine manufacturer. In addition, the module introduces the gland seal steam system and turning gear. A carbon ring has three segments held together with a garter spring. To prevent air from entering into the turbine casing, sealing steam is led to the turbine glands. The ejector used with the precondenser can be the type p. Upto approximately 40% load steam from auxiliary source crhaux.
Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and. When the gland seal is a steam seal type, a gland condenser and a gland exhaust fan are installed. The pressures at these penetrations are apparently much higher than that seen on internal combustion engines and require a different sealing tec. Gland seal the floating type labyrinth packing is fitted to seal the. If leverage points are unfavourable, the valve sealing reliability improvement live steam control valves are key components for the operation of steam turbines. A gland sealing steam supply system according to claim 6, wherein said system further includes a gas turbine, and a waste heat recovey boiler used for recovering heat of a waste gas from said gas turbine and having a highpressure steam generating portion consisting of an economizer, a highpressure steam generator and a superheater, and a low. The large, turbine gland sealing systems are basically self sealing, in the sense at a load 40% hp steam coming out from the hpt side could be enough to seal the same on the lpt side.
The gland sealing steam system provides lowpressure steam to the turbine gland in the final sets of labyrinth packing. Lund university lth energy sciences tpe magnus genrup 20171002 9 swedish steam turbine technology. Influence of steam leakage through vane, gland, and shaft seals on. All repairs are verified by functional testing and calibration. A gland seal system can be as simple as a spray chamber, loop seal and a steam ejector or as complex as surface condensers, air blowers or vacuum pumps. In simple words i can explain you that during the starting of the turbine the pressure used to rise inside the turbine while the outside remains as a atmospheric temperature. How does the steam turbine gland sealing system work. In order to accommodate the range of temperatures experienced throughout the turbine, the system is usually divided into two parts. Gland sealing in general purpose steam turbines processing. Retrofit of a steam turbine with dry gas seals james r. D hold the nozzles of the stage and admit steam to moving blades if choice d is selected set score to 1. Development of steam turbine inlet control valve for. A steam turbine package has several components and systems including.
Steam turbine sealing steam system overview youtube. Function and system layout the two functions of the turbine glands and seals are. The temperature range is up to 550 c, with the pressure ranging from 8 300 bar depending on the position of the valves in the installation. This system also prevents air leakage into the low pressure turbine glands. Control valve upgrade solutions for wesel steam turbines fact sheet g offers valve improvements exploiting latest technology. Upgrading diaphragms and resizing gland seal systems also offer reliability improvements.
Updating the turbine controls with an overspeed trip system enhances. Gland sealing steam supply system for steam turbines. The main steam stop, guardian and bulkhead stop valves are to be shut prior to maintenance work being carried out. The sealing steam first passes through the throttle steam valve and then the safety orifice in order to reduce its pressure to 0. Retrofit of a steam turbine with dry gas seals 47 reduced life for the gland seal condenser from excessive moisture impingement. Conventional gland sealing in general purpose steam turbines is accomplished with carbon rings. We also lead the industry in the duplication of parts and assemblies for rotating equipment such as steam turbines, compressors and more. Overlooked gland seal can be big trouble power services group. Gland steam system a high pressure steam turbine is having a sealing gland, where, the turbine rotor penetrates the casing of the turbine. Ett systematiskt arbetssatt har anammats under projektet och en detaljerad. Nov 19, 2016 function of gland steaming in tur bine operation. Each valve combination consists of a trip valve and a conhydraulic control system in steam turbines. Both the side gland leakoff line are connected to gland condenser.
Turbine gland steam condenser valve control theory. Ger3705 ge steam turbine design philosophy and technology. Turbine glandsealing system gland sealing provided to turbine. In the case where a simulated test would be unsatisfactory and. Instruction manual for single stage 350, 500, and 700 frame. Standard practice for design of steam turbine generator oil.
Control systems maintenance testing and maintenance of any turbine control system alongside a berth is strictly forbidden under live steam conditions. Therefore, efforts must be made to reduce the air leakage by checking all connections, seal glands, relief valves, etc. The lube oil auxiliary system provides lubricating oil to the steam turbine bearings to. The turbine generator is equipped with an electrohydraulic control system and supervisory instruments to monitor. Grt steam turbines alstom pdf catalogs documentation. And sealing steam lines are connected to a flush chamber through a pressure control valve. Us4793141a gland sealing steam supply system for steam. The gland sealing steam system provides lowpressure steam to the turbine gland in. Fire resisting fluid acknowledgements glossary bibliography biographical sketch summary steam turbines consist essentially of a casing to which stationary blades are fixed on the. As shown in the figure below, this system is composed of a transmitter. In steam turbines low pressure turbine lpt directly connected to condenser and condenser work under vacuum so its natural that air can ingress into.
Speed control system turbine gland seal the turbine glands. Re utilization of gland steam for optimized efficiency in. Then the sealing steam is routed from the inlet side gland 2 towards t. Gland steam must have appropriate temperature and pressure which must be controlled during startup. Steam turbine advanced sealing system mda turbines. Elliott engineered solutions redesigns steam turbine flow path aerodynamics to meet changing performance needs.
This gland steam must be removed by an ejector or other vacuumproducing device to prevent it from flowing back into the turbine. Steam turbine gland seal control system westinghouse. Excess pressure excess gland seal also has to be removed and put into the gland steam condenser. Gland steam sealing system for steam turbine youtube. The general features and selection criteria and use depending on the type of steam turbine are summarized in. Turbine gland seal steam system turbine steam scribd. A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful mechanical work. Main turbine generator the main turbine is an 1800 rpm, tandem compound six flow, reheat steam turbine. The drive for improved reliability and availability resulted in the industry backing away from both the 1050f steam temper atures which were common in the late 50s and early 60s and the 3500 psig supercritical throttle. The turbine gland sealing system tgss prev ents the escape of steam from the turbine shaft and casing penetrations and the glands of main steam stop and control valves. Standard practice for design of steam turbine generator.
Under certain conditions the gland is sealed by an auxiliary steam supply, and under other conditions the gland is self sealed by turbine inlet steam. Dec 03, 2015 the steam turbine gland steam seal system is designed to keep steam from leaking out of the turbine and to prevent air from leaking into the turbine. Explain the theory of operation describe the major components. We offer and extensive inventory of pressure bellows, high pressure steams, seats and piston rings. The gland sealing system is designed to supply steam to seal the turbine shaft glands at all operating conditions and to extract leakoff steam from the glands. This assists the labyrinth packing in sealing the turbine to prevent the entrance of air from reducing or destroying the vacuum in the associated condenser. Main steam system also supplies the steam seal system and the auxiliary steam system when other sources are not available. Changing journal bearings to tiltingpad bearings can improve reliability. The rotordynamic coefficients associated with steam leakage through the three labyrinth seals were calculated using the controlvolume method. The turbine gland seal system consists of a gland steam evaporator, sealing steam pressure regulator, sealing steam header, a gland steam condenser with two fullcapacity exhauster blowers, and the associated piping, valves and instrumentation. Simultaneously, gland steam system is started to prevent air inleakage. Up to nearly 40% load lowpressure auxiliary steam is. A steam turbine gland seal control system for a steam turbine driving an electrical generator which supplies power to a load after main circuit breakers are closed, and in which the gland is self sealing by steam in the turbine after said closing, comprising. For turbines supplied with options such as forced or circulating lubrication systems, alternative speed control systems, accessories, instrumentation, speed reducers or other special configurations, refer to the appropriate accessory manuals and turbine certified drawing package included in appendix a and appendix b following this manual.
Steam turbine gland seal control system patent osti. Boiler supply steam is used until there is sufficient pressure in the cold reheat circuit to supply the gland sealing steam. General purpose steam turbines are typically classified with output ratings below 3,500 horsepower 2. The oil system generally includes high pressure, bearing, control, generator seal, and drain systems. Main steam enters the hp turbine through control valves. Are we confussion hp and lp turbine sealing systems with the fact that a single steam seal system has two headers, the sealing header with is low pressure, pure steam and the gland exhaust header with is just a few inches of water less than atmosphiric and is a mix of sealing steam and air that ingresses at the turbine ends going to the gland. Turbine gland seal steam system free download as word doc. The tutorial is introduced by discussing the basics of steam turbine systems including the thermodynamic background, principles of operation, and the different classifications of steam turbines. Lockup and wear of the coupling, due to centrifuging of the lubrication causing premature failure. Overall design approach the design of reliable, efficient steam turbines requires the application of many diverse areas of technology.
I failed the gland sealing system test at my large steam turbine field engineering training, so ill have to go look at my manual to answer the rest of your questions. Unique systems designs and manufactures process vacuum systems including condensers, steam jet ejectors, liquid ring vacuum pumps and hybrids along with instrumentation, complete automation and auxiliary equipment. Function of the gland steam pressure control system. The upper gland, compressing the upper sealing, is adjusted and inspected. In steam turbines low pressure turbine lpt directly connected to condenser and condenser work under vacuum so its natural that air can ingress into condenser from shaft casing interface. Enables plant to monitor steam turbine generator condition since last overhaul addresses 17 systems components identifies riskrelated recommendations for future outage work colorcoded green. This module provides an overview of the steam turbine support systems, including common terminology related to the system. Unique systems has developed standard gland steam exhauster equipment, with both single and. The integration of the reverse engineering parts process into the steam turbine outage planning and execution ensures that parts can be supplied during ongoing overhauls. This system ensures the sealing of glands in hp, ip and lp turbine under various load conditions. Instruction manual for single stage 350, 500, and 700.
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