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Classification of steam turbines. • Working principles. • Pressure and velocity compounding. • Losses in steam turbines. Losses in steam turbines. • Design. PDF | Chapter-4 (Steam Turbines): CLASSIFICATION OF STEAM In book: Power Plant Lecture Notes, Edition: 1, Chapter: CHAPTER Steam turbine. A rotor of a modern steam turbine, used in a power plant. A steam turbine book Dampf und Gas-Turbinen (English Steam and Gas Turbines). .. [ 18] weinratgeber.info [19] Streeter.

Gas turbines can be designed faster, with increased flexibility, better materials, and optimized efficiency. Its outstanding advantages are: - exceptional reliability, We briefly discuss about Water tube boiler parts and functions. Gas Turbine for Power Generation: Introduction. Startup control brings the gas turbine Zero speed up to Operating speed. As in any gas turbine engine, exceeding temperature limits, even for a very few seconds, may result in serious heat damage to turbine blades and other components.

Primary system design considerations include: Minimizing resistance to gas flow back pressure and keeping it within the limits specified for the particular engine model and rating to A boiler is a self-contained combustion system that heats water.

As industry leaders in turbine inlet air chilling technologies, Stellar Energy has designed and supplied TIAC systems for electric utilities, independent power producers, municipal power-generation facilities, industrial power islands and liquefied natural gas facilities across the globe.

The selection of a fuel type depends on variables such as storage, cost, and accessibility. Microturbines, as the name implies, are small combustion turbines that burn gaseous or liquid fuels to drive an electrical generator, and have been commercially available for more than a decade. To create the adequate model it is necessary to take care about the functionality of the main parts of gas turbine and define the cause-and-effect connection between them. This way, 3D printing enables cutting edge technologies with reduced time-to-market and quick upgrading of existing assets.

The gas turbine is a power plant that produces a great amount of energy depending on its size and weight. Page Figure 4. Oil is the lifeblood of the aircraft engine. Wind turbines are mounted on a tower to capture the energy from the wind. Disadvantages of steam turbines 1 High efficiency is ordinarily obtained only at high speed.

Spares in Motion is the trading platform for wind turbine parts. In a gas turbine, a pressurized gas spins the turbine.

A turbocharger consists of a compressor and a turbine connected by a common shaft. The fuel is injected and ignited. Thus, a running gas turbine is basically free of the vibrations normally found in piston models, which translates in much longer service life TBO and higher reliability. The main elements common to all gas turbine engines are: An upstream rotating gas compressor; A combustor; A downstream turbine on the same shaft as the compressor.

There are four main fuels used in internal combustion engines. This page focuses on the gas turbine engine, the differences between types of turbines, and items to consider when they are applied as the prime mover.

A steam turbine is a device that converts the thermal energy of steam into mechanical energy by turning the blades of a rotor. The armature of the AC exciter, the rotating rectifier, and the turbine-generator field are mounted on the same shaft, eliminating the need to lead out the DC output to a stationary part, thus eliminating the necessity of such sliding parts as a commutator, slip rings, and brushes.

Additive Manufacturing can speed up gas turbine repairs, prototyping and manufacturing of parts. By selecting special materials or applying coatings to relevant parts, the service life of these compo-nents can be lengthened substantially.

The temperature of turbine gases must be closely monitored by the pilot. If the gas turbine is not operated at this load level, the flow triangles in the com-pressor and turbine expander stages will differ from design assumptions, and more energy will be dissipated. In the water tube boiler, the water and steam flow inside the tubes and the hot gases flow over the outside surfaces.

At the heart of a combined-cycle power plant is the gas turbine, the machine that has the power to make a good solution great. The present chapter firstly reviews known works on nonlinear dynamic engine modeling centering on Compared to a piston, the gas turbine has less parts and the moving parts rotate in only one direction without stopping and accelerating as the pistons normally do in an engine.

The schematic diagram of a Francis turbine is shown in Fig. In all modern gas turbine engines, the engine produces its own pressurized gas, and it does this by burning something like propane, natural gas, kerosene or jet fuel. This manual does not for designing steam turbine and the related parts.

These ultra-micro gas turbines are still in the research stage of their development but they offer intriguing possibilities. This unit is primarily concerned with the maintenance procedures and practice associated with aircraft gas turbine engines and propellers.

While each of the engines are different, they share some parts in common. Gas turbine functions in the same way as the Internal Combustion engine. Thapar 6. The low pressure compressor is from the 6FA industrial gas turbine. For the analysis of thermo-acoustic phenomena in gas turbine combustion systems flame transfer functions can be utilized. How does Gas Turbine works? Relative creep capability of titanium al loys used for compressor parts in the form of a Larson Miller plot Schematic.

Our global parts distribution centers are linked to regional supply chains, which means the highest-quality component inventory is on hand exactly when and where you need it. Formulae for the basic dimensions of turbine parts are well documented and a highly efficient machine can be reliably designed for any fluid flow This makes the transmission system rotate and the wheels of the vehicle moves. This test will be based on the manufacturers Factory Acceptance Test.

The output power of the gas turbine is directly proportional to the combustor firing temperature; i. Included is a description of the exhaust system, air intake, starting and fuel systems.

Exhaust Systems Well-designed exhaust systems collect exhaust gases from engine cylinders and discharge them as quickly and silently as possible. The manufacturer's recommendations should always be strictly adhered to.

Blade erosion Although the steam supplied to turbines is nearly always superheated. Great care should be taken to see that the astern manoeuvring valve and double shut off valve are shut tight as any leakage. As power is being increased always check the turbine casing expansion arrangements. To check the vacuum raise it to the full operational value. Do not use astern steam unless itis to check the ahead movement.

This procedure allows a small flow of steam for heating the turbine and the flow may be assisted by using the air ejector to provide about mm Hg of vacuum. Whilst waiting for the first telegraph order and during subsequent stand-by periods. Once the solid droplets strike a solid surface. After 'Full-Away' has been ordered. The turbines can be held in this condition until a short period before stand-by. Also ascertain that there are adequate water supplies to the lubricating oil cooler.

Open the manoeuvring valve bypass warming through valves. Start the lubricating oil pump and see that the oil is flowing freely to each bearing and gear sprayer. Always check the ammeter reading as a high reading gives a warning of trouble. Usually a sharp blast of steam is the best way of doing this. Bled steam valves may be carefully opened after ensuring the steam lines have been well drained.

On systems with no gravity tank. Cracking open the manoeuvring valve or use of gland steam above may have to"be adopted if these are not fitted. Verify that the expansion arrangements for the turbine are allowing freedom of movement. Certain classes of vessel may adopt variations in warming through procedures according to particular trading requirements.

Ascertain from the bridge that the propeller is clear in preparation for turning the engines. Engage the turning gear and rotate the turbines in each direction to ensure freedom of rotation. Top up the gravity tank. The turbine should then be slowly worked up to speed. The engines are now ready for use. The turbine will be designed for the steam flow speed to match the blade speed so that the steam flows across the blades with minimum friction.. If in these LP stages the speed of the water droplets is below that of the steam flow.

During this time the turbines should be rolled continuously on the turning gear. Adjust air ejector steam or condenser air extraction device and the gland steam so that the minimum gland steam is required to maintain a vacuum of about mm Hg in the condenser.

Start the condensate extraction pump with the air ejector re-circulation valve wide open. All bled. Turn on the low level alarm for this tank. Warming-through procedures Prior to warming through the turbines. Disengage the turning-gear.

The presence of any water should also be checked for. Open all the turbine casing and main steam line drain valves and make sure that all the steam control valves at the manoeuvring gear and about the turbine are closed.

Admit sufficient steam to the ahead turbine to move the propeller shaft about one revolution. Start the S. Repeat this procedure approximately every three minutes for at least fifteen minutes. These droplets can promote erosion. In some cases the blade speed is kept below a certain value. Operation at low superheat temperatures. Eventually the blade mafail due to a weakened section. This impact will produce a retarding effect on the blades. Static and dynamic balancing However much care is taken in the manufacture of a turbine rotor.

Erosion has been known to undermine these strips so that they are thrown off causing serious damage. Other methods adopted involve the use of reheating the steam after the HP turbine exhaust to the initial steam temperature so that the expansion is completed at the dry saturated steam condition. This action takes place over the whole length of the blade and results in an ever larger concentration of moisture towards the tips of successive rows of blades.

Although the retarding effect of the water droplets striking the back of the rotor blades is a propulsive loss. The alternative is to remove some material say at point R. Such a discrepancy provides a mass of metal on a particular section of a disc or blade which is heavy compared with the rest. The LP astern turbine when running in the ahead direction tends to act as a compressor.

To offset this tendency either another mass can be placed on the opposite side to the one causing the trouble to give an equal and opposite correcting moment. Some of this water is thrown from the blade tips and is trapped in narrow annular water traps in the casing.

This is the equivalent of static unbalance of the rotor. In b e cases special bolt heating elements may be used to facilitate this process. During normal operation vibration may increase slowly over a considerable period of time and may be due to out of balance forces caused by erosion or the build up of carry-over deposits on the blades..

As the bolts are eased back.. Slacken back on the casing bolts. When slackening back on the joints. A local distortion may then be set up which could cause a rub between the casing and rotor.

In some machines. It will also show dynamic unbalance by vibrating in a transverse plane as shown by arrows Y and Y. Such a couple could cause severe vibration in a turbine running at speed and it is the purpose of dynamic balancing to ascertain where the balancing masses should be placed to prevent such vibration occurring.

Any steam pipes connected to the top half should then be disconnected 38 A turbine rotor. In modern machines electrical pick-ups are used to measure the vibrations. Obviously in this simple case if Q or R were used on the same disc as P. This may be done whilst the turbine is still warm.

The rotor remains straight and under the influence of the out of balance masses tends to move horizontally from side to side. On a large turbine. Over a particular small range of speeds this bow will tend to become excessive and a very severe vibration effect will occur.

Rapid changes in vibration from normal behaviour indicate a serious deterioration in operating conditions. There is generally a barred speed range for the turbine operation which is this critical speed.

Remove any pressure gauge connections and gland housings. The rotor is run at a slow speed. Turbine inspection With most turbines the first procedure is to remove the lagging from the horizontal joint of the turbine and check the expansion indicators to see that the casing has returned to the normal cold position and is not being held in a distorted condition.

The two halves of the HP turbine casing are held together by bolts of creep resisting high tensile steel and in many cases special gear is provided to make sure tha all the bolts are stressed to a condition so that the cylinder joint faces remain t steamtight when subjected to the full working temperature and pressure. In the event of damage to a rotor or its associated primary reduction gearing to the extent that it is impossible or unwise to continue operating the damaged unit.

The LP turbine. Electric heating elements are then placed in holes drilled in the bolts which are then heated up until the nuts can be turned so that the scribed lines coincide. These columns have flanges at each end and are placed at each corner of the turbine with bolts passing through the flanges securing the columns to the top and bottom casings.

Before lifting the rotor. The rotor is then slowly lifted clear of the bottom casing. The lifting gear will depend upon the particular installation and usually consists of chain blocks from beams overhead attached to brackets fitted to the casing into which shackles are fitted. In general it will be necessary to isolate the damaged unit by fitting the inlet and exhaust pipes with blank flanges.

The inner edge of these guides is shaped to fit into the journal in way of the fillets so that fore-and-aft movement is prevented. In this particular arrangement. The outer casing joint external bolts have to be removed and before this can be lifted care should be taken to see that the design does not involve: Once these have been removed the outer casing may be lifted and placed to one side and the inner casing dealt with as previously described.

These pillars are used to prevent the top casing swinging whilst being lifted. If the rotor is to be lifted. The vessel is usually supplied with special portable pipe lengths.

Access to these is usually made through inspection doors in the casing. A gauge is then placed on the end of bolt and nut and lines scribed across the faces of both. Slings are then passed round the shaft. The general procedure is to tighten up the bolts by means of a spanner. These are fitted through the access doors and it is essential to check that these brackets are removed when the turbine is boxed up after the inspection as they can seriously impede the flow of steam to the condenser.

Guides are now fitted at each end of the rotor in way of the bearing journals. These pipes will either be of reduced di ameter or have orifice plates fitted to li mit the pressures to those allowable i n the working units.

Wood is usually placed on top of these bars for the rotor to rest on. When the casing has been lifted clear of the rotor it may be moved clear of the turbine or supported on columns above the rotor. In some modern designs 'intrascopes' may be inserted into the turbine at selected points to enable periodic inspections to be carried out without having to lift the top half cylinders. The manufacturers usually prescribe a particular pattern for tightening up and slackening the bolts. In some cases both inner and outer casings are lifted together and then it may be necessary to fit brackets to support the inner casing from the outer.

Depending upon the design. Such an occurrence involves the disconnection of the affected rotor. The elements are then removed.

The procedure will vary somewhat according to different manufacturers. This condition makes the gear teeth susceptible to separation and possible damage.

All LP bled steam valves should also be shut. Operating procedures will depend upon the degree to which the superheat temperature can be adjusted. Staff should of course remember to open In many i nstallations automatic drain valves are fitted. If only the turbine is damaged. The water is usually supplied from connections to the extraction pump.

Any signs of abnormal values should be carefully checked and operating conditions adjusted to bring them i nto line with those normally found. During warming through or manoeuvring procedures steam will condense on cooled surfaces of piping and casings. It is essential that all drain valves should be opened when warming through and manoeuvring at slow speeds to remove any condensed steam that may form.

Fit relief valves on the HP end of the exhaust pipe. As the plant will be operating under abnormal conditions with one of the turbines out of action. Restrictions in the'pipeline s will protect the condenser. This can produce l ocalized undercooling and distortion due to uneven heating which in turn may cause a rub to occur between the rotor and casing.

1st Edition

If ti me permits therefore it is good practice to remove the secondary pinion and so isolate the gear train. This enables the exhaust from the HP turbine to pass directly to the condenser. Blanks are placed at points Y and Z to isolate the turbine and the emergency piping as shown is fitted. Desuperheated steam via a control valve may be used.

Lubricating oil system The proper functioning of the turbines and gearing is dependent upon a continuous supply of lubricating oil at the correct pressure and of the correct viscosity. HP turbine bleed belt 7. Astern manoeuvring valve double shut-off. Ahead manoeuvring valve C.

As the steam pressure increases it acts on the valve head to overcome the spring pressure. HP turbine exhaust belt 8. LP turbine ahead nozzle belt 3. Qil film between sliding surf. With this arrangement. LP turbine bleed belt 4. Astern manoeuvring valve D. The drains are as follows: HP ahead turbine nozzle belt 6. Non-return valves and looped pipes are used to ensure that water can never be drawn back into the turbine casing.

Steam Turbine Speed Controls and Safety Systems

Astern manoeuvring valve double shut-off drain A. In some early designs and with some turbogenerators the ' drains were led to the tank tops. At the lower pressure and temperature regions of the turbine installation. The oil has two important functions to perform in the operation of turbines and gearing.

In this system oil is drawn from the drain tank in the double bottom of the ship by a pump. Turbine drain system The automatic drain valve shown in Fig.

Steam strainer B. Steam strainer 5. This has a number of grooves around its circumference to permit free drainage.

In some designs the pumps are placed before the magnetic filters. The drain tank is usually fitted with an easily observed float gauge indicating the quantity of oil present. Oil should always be visible in this glass. This tank may contain about litres of oil and must last for at least six minutes.

The steam passing through each annular space between the tips of the fins and the adjacent shaft is subject to a throttling action which reduces pressure and increases velocity. Some arrangements incorporate an engine driven pump together with an electric pump and instead of the gravity tank being at the top f the engine room the eme en 1 supply is stored the upper corners of the gearbox structure.

Steam Turbine Books

These valves have holes drilled through the lids so that the oil supply cannot be completely cut off. Pumps may be of the reciprocating type. Some systems incorporate coalescing filters to remove water. There is also a supply valve for filling the tank. An oil detector ma be fitted 9n the. Various means are adopted to ensure the supply of oil to the bearings and gear sprayers in an emergency.

To be effective the incoming jet must not be allowed to flow towards the next opening and pass straight through. This consists of projections from the rotor and casing providing a series of and narrow spaces through which steam leaks.

The bearings are fitted with valves to adjust the i flow. By dividing the gland into a number of sections and using reservoir and collection vessels it is possible to have definite known pressure drops over each section.

After passing through the bearings. Two filters are usually fitted. In very hot climates it may be necessary to use both coolers to keep the oil temperature down. The labyrinth gland is therefore a series of nozzles.

In this way the number of stages can be calculated for a given flow of steam. Two independent pumps are usually fitted and if one stops. In some vessels filtration down to 5 microns is carried out and purifiers may be employed which operate under vacuum conditions to remove virtually all traces of water.

After being discharged from the pump the oil passes through full flow static filters which may be of the edge type or disposable element design. After passing through the coolers. Flow sight glasses are sometimes fitted to the outlets from the bearings. The coolers have bypass valves fitted These should be kept open until the oil has reached approximately This increase in velocity is dissipated by turbulence and' the formation of eddy currents of steam as it flows into the expansion chambers between each segment of the gland.

From the filters the oil passes to the coolers where the sea water passes through the tubes and the oil over the outer surfaces. Where there is insufficient h eadroom availakle j.


This in turn produces more heat and the effect becomes self-accelerating getting progressively hotter until a point is reached at which plastic flow occurs and the material yields in compression. The shaft on cooling then takes up a permanent set.

Radial springs act on each gland segment forcing it into a shoulder in the casing to give the normal radial running clearance of about 0. It is supplied via point A and distributed by way of pipes B. The remaining steam leaking through this gland then passes through the next set of labyrinths where its pressure is dropped and it is leaked off to the cross-over pipe between the two ahead turbines.

In the HP inlet shaft gland. This reduces the amount of heat generated. Contact between the shaft and gland will at first be over a small arc of the rotor surface. It has been found that the spring loaded gland can deal with such a situation well and has considerably reduced the incidence of shafts bending due to gland rubs. Modern turbine designs use a spring backed gland as shown in b.

This design tended to propagate cracks and has been abandoned. Under conditions of normal operating powers with high pressure in the HP turbine. Material for the gland segments must be such that if the rotor came into contact with the labyrinth fin.

With some HP turbines where there is a considerable pressure drop to be dissipated in the gland and which would require it to be disproportionately long. With the solid design the fin is thinned away at the tip to reduce the area of contact if a rub occurred.

The third and fourth leak-offs link up with the main gland steam system for the other glands. Brass has been used to a considerable extent and copper alloy with a lead content has been found suitable. Here it joins the main steam flow to the LP turbine to be expanded through the remaining stages.

Under full-away conditions the manoeuvring valve is opened wide and the individual nozzle box valves opened wide in various combinations to provide the desired rate of steam flow for the power required. The bleed-off pressure can be adjusted. As the power developed by a turbine depends upon the mass of steam flowing across the blades per second.

A greater quantity of steam passes 51 turbines. Excess steam which passes the inner shaft seals is extracted at the outer sealing chambers. When adjusting the pressure the valves are first closed fully. The pressure at these points is manually controlled by butterfly valves 4 and should be just below atmospheric. There have been a number of cases of turbine blades being stripped due to the failure to observe this practice.

If the plant is operating below normal power and there is insufficient sealing steam of E. The bottom of drain collector 6 is connected via an orifice 9 to the condenser hotwell. It used to be found on the old Parsons impulse reaction Partial admission is a term used in conjunction with impulse turbines.

The used cQ. The extracted steam passes to drain collector 5 which is connected to a U-pipe which should be about mm to counterblance the sub-atmospheric pressure caused by fan 7.

All-round admission. The required sub-atmospheric pressure in the gland steam leak-off circuit is approximately mm w. Steam passing valve 8 is condensed in the gland steam condenser 19 and air is extracted by fan 7. The approximate gland steam pressure is 1.

The uncontrolled group is controlled directly from the manoeuvring valve. When operating at full power there is an excess of steam leaking from B. Foriimanoeuvring to ensure maximum power availability and to reduce the steam load on the blades. The overall steam supply to all the nozzles is controlled by the ahead manoeuvring valve. Should overload conditions be required. Steam then leaks through the shaft collars whereupon the valves are opened sufficiently wide to stop this leakage.

For overload conditions or power conditions in excess of normal a bypass valve is used which admits steam to a belt a number of stages down the turbine from the HP inlet. C and D and this is then bled off through an overflow valve 8. By employing nozzle control in this way the steam supplied at boiler pressure and temperature expands over the pressure drop so that the greatest release of heat possible per unit quantity of steam flowing per unit time is achieved for any power requirements..

C and D to E where it supplies sealing steam to the astern turbine gland. For vessels on long voyages.

Due to the very low specific volume of the steam at this point. The general arrangement is shown in Fig. Both ahead and astern manoeuvring valves are designed to give a lift to flow roiationship. Curve C represents sequentially operated manoeuvring valves..

The expansion through the turbine now takes place from a lower pressure and the heat drop available is reduced so that this form of control tends to make less use of the heat drop available and is therefore less economical than nozzle control for reduced powers.

The cams will be characterized. These valves are hydraulically operated using oil at a pressure of about kilo-newtons per square metre and incorporate a cam opera ted. The heat released is determined by the boiler pressure and temperature and the condenser conditions. As the manoeuvring gear is operated each valve opened up in sequence.

The expansion across the individual nozzle groups is the maximum possible. The power of a turbine is dependent upon the heat released from a given quantity of steam and the mass of steam flowing per unit time.

With other designs the valves are opened by cams fixed to a cam shaft driven by hand or power operated equipment. As the beam is lifted.

During the course of a voyage there may be passages of considerable length between ports when a vessel is required to operate at reduced power or powers in excess of normal. Power adjustments must therefore be made by keeping the heat released constant and varying the quantity of steam flowing as with nozzle control. If the manoeuvring valve is partly shut in. Curve A represents a single manoeuvring valve with all hand control valves open.

The design of the. Curve B represents a single manoeuvring valve with correct operation of hand control valves. A simple governor provides speed control for the ahead valve. The manoeuvring valve is replaced by two or more valves. As the cam shaft rotates successive values and nozzle groupings are opened up to the steam flow. High vibration amplitude Under normal operating conditions the toggle switch is in the lower position as shown Fig.

HP turbine overspeed end movement 9. Should one or more of the protection devices operate due to a disturbance. This prevents uncontrolled opening of the valves. Switch B is closed when the manoeuvring valves are shut. Second reduction gear wheel 8. After the fault has been rectified. The fault trips are placed in series so that the supply current must flow through each one before passing through and thus energizing the solenoid valve coil.

The upward movement of the toggle switch closes the switch energizing the lower toggle switch solenoid. Turning gear engaged For manual testing the switch A is operated by a sf:? LP turbine axial displacement 6. The drop in pressure in the control oil circuit causes the spring in the manoeuvring valve servomechanism to shut in th6 valve and thus stop the turbines. Manoeuvring valve servo motor 54 Fig. Low vacuum 3. HP turbine axial displacement 4. Low lubricating oil pressure This upper solenoid is then energized and lifts the switch to energize the visual and audible alarm circuits and at the same time break the circuit to the control oil solenoid: With the coil de-energized.

Manual trip from control room 5.

LP turbine overspeed 7. Tripping devices are provided for components or systems should one or more go into a fault condition: High condensate level 2.

If it is required to shut in the manoeuvring valve. The piston is then forced down against the spring. Valve seat. Valve seat and gaskets.

If the solenoid valve in the trip system in Fig. If the spool valve is moved up. Steam inlet d. Flats for spanner c. Nut for forced closing. The oil flow is now shut off and the servo-piston is held in its new position. The valve head is fixed to the spindle 3 by means of a dowel. Bellows assembly 9. When the astern manoeuvring valve is operated.

Nut to clamp bellows assembly It is only in this position when the valve has to be operated by hand in an emergency. The seating surfaces are stellite coated. Valve casing. This movement operates the negative feedback linkage connected to the sliding sleeve on the outside of the spool valve. Lantern ring for the spindle leakoff steam 8. The valve seat 6 forms the seal between the flanges. This movement. Locking pin for nut 10 Normally the pin in the manoeuvring valve spindle would not be in the position shown.

The servo cylinder 14 is welded to the valve casing. The seating surfaces are stellited. The spool valve is operated by the control system and speed governor via a hydraulic.

Steam-turbine Principles and Practice

Valve head. Drain 1. Servo-piston a. Oil sealing ring e. Guide bush for valve spindle 3. Oil supply g. Steam to astern turbine Split pin for locknut 12 Oil pressure acting through C holds the valve shut. Oil drainage now stops and the manoeuvring valve is held in its new position.

Spindle leakoff branch b. In the electro-hydraulic emergency cutout system a tripping signal to the hydraulic solenoid valve opens the passage to the plungers in the servomotors. The spring is deflected by the adjusting screw E. The position is then read from the scale and the spring returns the lever and holds the end of the rod from the rotor. A spring B with weight A is rolled into the end of sleeve C which is inserted into the end of the turbine rotor D.

For testing purposes the unit may be tripped by rod 5 which projects from the end of spindle 2. Each monitor consists. During normal operation the plungers in the hydraulic valve are depressed by the power oil pressure. When the turbine overspeeds the weight. The astern servo opens when power oil enters the servo cylinder. The trigger spring 3 must only be replaced by an original spare part as a spring with the incorrect loading can seriously damage the overspeed pendulum.

The ahead valve closed and the Guardian valve relay changes position and the Guardian valve opens. The minimum selector chooses the lowest oil pressure and the propeller speed then decreases.

This is normally covered by a cap to prevent accidental tripping. Manoeuvring and cut-out circuit Fig. For astern movements the spring plate is stepped towards the left-hand oil nozzle by means of a stepping motor. Turn the nut 13 with a spanner so that the spindle moves in the valve closing direction.

The spindle should not be rotated since the bellows 8 would be damaged. Excessive end movement of the rotor causes axial movement of spindle 2 which in turn allows slide 8 to move and thus actuate the limit switch. The pump supplies oil at 10 bar to servo motors P. The control oil pressure to the astern servo increases. The manoeuvring valve then closes instantaneously.

Power oil is led through relay to the Guardian valve servo motor. The control oil pressure N determines the power oil pressure in the servo cylinder and consequently the speed of the turbine. For ahead movements the control oil pressure N to the ahead servo motor increases when the spring plate in the impulse converter is kept close to 58 the oil nozzle. First published: Tools Request permission Export citation Add to favorites Track citation.

Share Give access Share full text access. Share full text access. Please review our Terms and Conditions of Use and check box below to share full-text version of article. Abstract No Abstract. References Related Information. Email or Customer ID. Forgot password?Valve seat and gaskets.

This impact will produce a retarding effect on the blades. Despite efforts to develop alternative energy converters, electricity from steam will continue, for many years, to provide the power that energizes the United States and world economies. The pump supplies oil at 10 bar to servo motors P.

As soon as we find all transfer Learn about the working of Gas Turbine power plant auxiliary systems in this article.

The single wheel carrying the blades may be forged integral with the rotor-or keyed or shrunk-force fit onto the rotor. The rotors also tend to lLoog in similar fashion if they are noti rued fre uently.

This then allows expansion in both longitudinal direction and thwartships, but the sliding foot or panting plate arrangement will still be used to provide longitudinal expansion.

Under these conditions the valve should be steam tight and attempts to reduce any leakage by jamming the valve shut are useless considering the load being exerted by the steam pressure on the valve lid.

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