US1617047A - Steam plant - Google Patents

Description

Feb; 8, 1927.

- 1,617,047 G. FORNER STEAM PLANT Filed June 27, 1923 Bo/LER /////////1IW////%I7////////////; C

' lhhL 5:207 ZZfW/ZT ltl Patented Feb. 8, 1927. i

UNITED STATES PATENT OFFICE.

I GEORG FORNER, OF BERLIN, GERMANY.

. STEAM PLANT.

Application filed June 27,1923. Seria1.,No. 648,073, and in Germany June 28, 1922.

This invention relates to steam turbines or other motors operating in con unction with steam accumulators of highly varylng pressure. In plants embodying such units an approximately constant quantity of steam is iisually supplied by the boiler. the steam which is not used bythe turbine at moderate load being used for charging the accumulator and the additional quantity of steam required by the turbine at higherload being obtained by withdrawing steam from the accumulator and supplying the turbine therewith. In the turbine plants of known type the charging steam is taken from an intermediate stage of the turbine and the steam withdrawn is admitted to the same stage or to .a following intermediate stage, the stage receiving steam from the accumulator having a set of nozzles and series control therefor of which only so many nozzles being open behind the point of withdrawal that the pressure in front of these nozzles differs from the accumulator pressure merely the amount of the unavoidable loss of pres sure.

This arrangement presents the inconvenience that the pressure at the point of withdrawal must participate in the great variations of pressure in the accumulator so that very great fluctuations are produced in the head ofthe two turbine stages adjacent to the point of withdrawal. On account of these strong variations of the head in the two stages adjacent to the point of withdrawal, the average efficiency of these stages is unfavorably influenced. A turbine of this type uses, therefore, in all. more steam than a turbine without accumulator otherwise of the same type, this surplus consumption amounting in most 'cases to over 5%. The improvement inefficiency of the boiler due to the uniform demand in consequence of the accumulator is reduced this amount.

This invention has for its object to reduce this loss to that which is absolutely unavoidable and this result is attained by making the variations of pressure in the turbine to a great degree independent of variations of pressure in the accumulator. Withthis objcct in view one or several elements are inserted in connections between the accumulatorand the turbine, which regulate 'the flow of steam according to requirements In one form of the invention steam, taken from the accumulator at a higher load on the turbine, is supplied to a "turbine stage which, in the direction in which the steam flow-s, is situated behind the stage from whiehthe steam for charging the accumulator is taken. noneof these two stages having an automatic series governing of nozzles. In this case the pressures at tbe point of withdrawal and at the point of admission are independent of the accumulator pressure and the only condition which hasto be fulfilled is that the pressure att'he point of withdrawal must be greater than the accumulator pressure and the accumulator pressure must be greater than the pressure at the point of admission. Although in this case a. loss from throttling is produced which is greater than the loss in commonly used arrangements, the influence of this loss on the consumption of steam is only a slight increase of the same as this loss from throttling occurs in only a small part 'of the steam and occurs only during discharge of the accumulator. In accordance with well known physical laws part of this loss is recuperated in the low-pressure part of the turbine. The remaining moderate loss is more than compensated for by the influence of the decreased variations of head to which the stages are submitted which are adjacent to the point of withdrawal and to the point of admission. These smaller variations of head give these stages a degree of effi'ciency which differs only slightly from the maximum degree. The average degree of efliciency of a turbine of this type is consequently but little less than that of an equivalent turbine without-accumulator. The increase of the consumption of steam may be estimated at about 1% so that the invention a'Eords an improvement by at least 4% of the steam consumption compared with that of the commonly used arrangements.

The invention will be best understoodfrom a consideration of the following detailed description taken in connection with the accompanying drawing forming a part of this specification, with the understanding that while on the drawings several embodi- .ments of the invention are disclosed, the in- Fig. 2 shows diagrammatically a turbine arranged according to a second form of the invention.

Fig. 3 shows diagrammatically a turbine arranged according to a third form of the invention.

Fig. 4 shows diagrammatically a turbine arranged according to a fourth form of the invention.

Fig. 5 shows diagrannnatically a pressure operated valve for use in place of speed controlled valves of certain modifications.

According to Fig. 1 innormal operation, a practically constant quantity of steam is supplied from the boiler 70 through the conduit a and the port h of the slide-valye 0 to the high-pressure nozzles of the turbine 75 which are not specially automatically governed. The position of the slide-valve c,

as shown corresponds with the condition that the turbine consumes exactly the quantity of steam supplied by the boiler. If the speed of the-turbine increases, due, for example, to decrease of load so that it requii es less steam than the boiler supplies, the governor pulls the slide-valve c to the left so that steam from an intermediate stage, in

' the case shown in Fig. 1 from the first chamber b, flows into the accumulator 3 through the port f of the slide-valve. If the load on the turbine increases so much that the steam consumption becomes greater than the quantity of steam supplied by the boiler is the speed governor displaces the slide valve 0 so far to the right that the withdrawal of steam from chamber 7) is cut oil,

' cut off partly or entirely.

Instead of a slide-valve three throttling valves may be used, which are controlled, from a common shaft operated by the speed governor. Instead of the direct regulation 0f the slide-valve or other means by the governor, indirect regulationby oil pressure or by any other well known auxiliaryde vice ispreferably selected. 1

Ifthe quantity of steam supplied by the boiler is occasionally for some time greater or smaller than the normal average quan tity, hand operated. auxiliary valves 2 are preferably used to' conduct fresh steam to separate high-pressure nozzles. As the separate nozzles work generally ,under other conditions of pressure than the normal nozzles it is advisable to design them with different dimensions, for instance other cross sections, angles, expansion ratios, etc. In the cases where the limits between which the accumulator pressure varies are very wide the head of the stage or stages situated between the point of withdrawal 6 and the point of admission (Z will be very great. In order to reduce this head the accumulator sis separated from the chamber d as indicated in Fig. 1 in dash lines, and the steam taken from the accumulator s during the discharge is supplied to the limited space 0 from which it flows through separate nozzles which may also be of other dimensions than the normal nozzles, thence to the following disk. This affords the advantage that a higher pressure may be maintained in the chamber (Z, so that the head occurring between the chambers b and (Z is reduced This head remains now almost unvaried and the variation of head occurs .in the next following'stage.

v The further advantage is added to the advantages mentioned that only one slidevalve or one shaft with three throttling valves is required and that they need be driven only from the speed governor (series governing of nozzles and influencing of the governor by the accumulator pressure b6-. ingomitted) whereby the security of service andthe sensitiveness of the governing are increased. series governing of nozzles presents the fur- The omission of the automatic ther advantage that the nozzle cross sec- 1.00

tions in all stages are constant for each stage the pressures and temperatures the exact quantity of steam which flows through when a valve is throttling strongly. This advantage which results from the omission of series governing of nozzles, must not be valued too low as it offers a simple. and easy possibility-to control the service witl steam'consumption. I

It will be seen from the above description that when the turbine load is substantially at average value'sothat a-balanc'e obtains 'betweenmotor plant load and motor plant steam energy supply, the parallel paths for steam to and from the turbine andaccumuout tedious and expensive measurements of lator are wholly cut off so that there is no accmnulator make a highly etlicient motor plant.

The embodiment shown in Fig. 2 is similar to the embodiment described above with reference to Fig. 1 and is preferably used when the highest accumulator pressure is so near the boiler pressure that the head between fresh steam pressure and the pressure in the chamber 6, which in the first embodiment must always be greater than the ac-. cumulator pressure. is not great enough to be economically utilized in a turbine stage. In this case the steam for charging the .accumulator at low load is taken from the fresh-steam pipe. and when the accumulator discharges at a higher load the steam from th accumulator is conducted into an intermediate stage of the turbine in which the pressure always lower than the accumulator pressure. The regulation is effected, as in the first embodiment, merely by the speed governor, which controls the deviation of the fresh steam to the accumulator, the amount of the fresh steam supplied to the first stage during charging and the discharging from the accumulator into an intermediate stage. In the embodiment shown in Fig. 2 an almost unvarying quantity of steam flows from boiler is through the pipe 64 and through port 71. of slide-valve c to the high-pressure nozzles of the turbine t. The slide-valve c is shown in Fig. 2-in the position at which the quant'tyof steam consumed by the turbine t is equal to that supplied by the boiler 7:. If the turbine speed increases, due, for example. to decreased load. the slide-valve 0 is pulled to the left, the fresh-steam pressure in front of the high-pressure nozzles (.lecreasing so that less steam flows into the turbine and the excess part of the steam supplied by the boiler flows through the port ot the slide-valve into the accumulator a. -Vhen the load increases so that the turbine consumes more stciun than the boiler supplies the slide-valve is pushed so far to the right that the port 7 of the slide is shut ot'r". the port h remaining fully open, and steam flows from the accul'nulator 8 through port 9 of the slide-valve into the chamber (Z of the turbine. Forthe slide-valve three throttling valves operated from a common' shaft may besubstituted and auxiliary valves adapted 'to be operated by hand might be arranged it? the high-pressure nozzles. Under the nated with reference character Z.

same conditions as mentioned with regard to the first embodiment the steam supplied from the accumulator to an intermediate stage of the turbine may be conducted into a separate chamber 0 in front of' separate nozzles of this stage, the separate nozzlesbeing also of difi'ere'nt dimensions than the other nozzles of. this stage.

In Fig. 3 a third embodiment is shown. From the boiler A an approximately uniform quantity of steam flows through the pipe (a to the turbine t traversing a number of controlled valves -i of which only one is shown in the drawing. If-the load sinks so that the quantity of steam consumed by the turbine is smaller than that supplied by the boiler the control valve Z opens and lets steam flow from the fresh-steam pipe at through the branch pipe m into the accumulator 8. When the load on the turbine increases so much that the quantity of steam supplied by the boiler l: is no longer suflicient, the valve 17, opens and lets steam flow over from the accumulator a through the pipe 0 into a chamber 1.! of the turbine t. The valves 6, Z, n may be operated from a common shaft 9 by the speed governor. The quantity of steam admitted through valve n from the accumulator to the turbine chamber (1 may again be conducted into a separate compartment 0 of this chamber in front of separate nozzles which may be of difi'erent dimensions than the other nozzles of the same stage. Instead of the valve Z operated by the governor an automatic pressure operated valve might be inserted into the branch pipe on which opens when the pressure in pipe a increases beyond an adjustable limit owing to the reduced steam consun'rption of the turbine. Such an automatic pressure operated valve isshown in Fig. 5 and desig- The valve is operated by means of a piston 10 acted upon on one side by a spring 12 and on the otherside by fluid pressure in a chamber 13.

In the modification shown steam acts directly upon the piston, being transmitted through tube ,14. Upon increase of pressure in conduit (1-. piston 10 is moved upwardly and raises the movable portion of valve Z thereby increasing the flow through pipe on to the accumulator. Upon decrease of steam pressure, in pipe-a, piston 10 is moved downwardly under the action of spring 12 to close valve Z and allow less steam to flow to the accumulator.

lVhen the highest accumulator pressure is nearly equal to the boiler pressure, the pressure in the first chamber of the turbine being however essentially lower than the accuniulator pressure, a fourth embodiment is pref-v erably used which is shown in F ig. 4. In this embodiment steam for charging the accumulator, at a low steam consumption of the turbine is taken from the fresh-steam pipe and the steam which is withdrawn from the accumulator on discharge of the accumulator at. higher load is conducted to separate nozzles of the first stage. This arrangement will have to be applied mostly in cases where the first turbine stage has to work up a great head owing to the use of :1 Curtis disk. An approximately uniform quantity of steam flows from the boiler throughthe pipe (z and through one or several controlled valves of which only one is shown in the drawing. to the high-pres-rure nozzles ot' 'the turbine t. As long as the turbine consumes exactly as much steam as is supplied by the boiler the valves Z and n remain closed. It the speed of the turbine increases the speed governor opens the valve Z through the intermediary of the common shaft q, and the steam in excess will flow over through the pipe m into the accmnulator s. Vhen the speed decreases so much that the steam supplied by the boiler is no longer suflicient the speed governor again closes the valve l and opens successively the valves 11, of which only one is shown in the drawing, so that steam may flow from the accumulator 8 through the pipe 0 to separate high pressure nozzles. These separate nozzles may be of different dimensions than the nozzles arranged behind the pipe a. Instead of the valve Z an automatic pressure operated'valve similar to valve 1 of Fi 5, may be mounted in the branch pipe'm, said pressure operated valve opening automatically if at decreas ing load the pressure in pipe a increases. If instead of the reduction of the losses from throttling produced by the use of the automatic governing by nozzles the advantage of the easier observation of the service is preferred, only one valve n andone valve i are arranged and auxiliary valves adapted to be closed b hand and connected with the pipes a and 0 are preferably used when a lower or higher load than the normal average load on the turbine lasts for a longer time.

I claim 1. In a steam plant, in combination, a source of steam, a motor, an accumulator. a

passage for steam from said source to said' accumulator, a throttling valve controlling said passage, a passage for steam from said accumulator to said motor, a throttling valve controlling the last mentioned passage, means to conduct steam from said source to said motor, and means responsive ,to the speed of said motor to control said throttling valves.

2. In a steam plant, in combination, a source of steam, a motor, an accumulator, a passage for steam from said source to said accumulator, a throttling valve controlling said passage, a passage for steam from-said accumulator to said motor, a throttling valve controlling the last mentioned passage,-

means to conduct steam from said source to said motor, and means responsive to the s need of said motor and o )e'ratin to hold both said throttling valves closed at a given speed, to open the first-mentioned throttling valve when the speed of the motor increases above said given speed and to open the second-mentioned throttling valve when the speed of the motor decreases below said given speed.

3. In a steam plant, in coml'iination, a source of steam, a motor having a clear uninterrupted passage for steam throughthe same, an accumulator, a passage'-l'oi"--steam from said source to-said accunmlator, a throttling valve controlling said passage, a passage for steam from said accumulator to said motor, a throttling valve controlling the last-mentioned passage, means to conduct steam from said source to said motor and means responsive to the speed of said motor to control said throttling valves 4. In a steam plant, in combination, a source of steam, a motor, an accumulator, a passage for steam from said source-to and through said motor, a passage for steam from said source to said accmnulator, a" throttling valve controlling the last-mentioned passage, a separate supply chamber in said motor, a passage for steam from said accumulator to said separate supply chamber, a throttling valve controlling the lastmentioned passage and means responsive tc the speed o1 said motor to control said throt tlmg valves.

5. In a steam plant, in combination, a

source of steam, a motor, an accumulator, a

above said given speed and to open the 1 second-mentioned valve when the speed of the motor decreases below said given speed.

6. In a steam .plant, in combination, a motor having a plurality of stages including a low pressure-stage, a source of steam, two parallel paths for steam from said source to said low pressure stage, one of said paths including an accumulator and means responsive to the speed of said motor to wholly cut off supply of steam to and discharge of steam from the accumulator while permitting passage of steam through the path parallel to the accumulator.

7. In a steam plant, in combination, a motor, an accumulator, means to' conduct s'team from said accumulator to said motor, means to supply steam to said motor and to said accumulator, said motor being arranged so that steam may pass through the same, and means responsive to speed of the motor to wholly out off the accumulator from the motor at a given'normal motor speed while simultaneously permitting passage of steam speed responsive means to control flow 0 through the motor.

'8. In a steam plant, in combination, a motor and an accumulator, a source of steam supplying steam to said motor and to said accumulator, a discharge conduit/conductin'g steam from the accumulator to the motor and means responsive to the speed of said motor to simultaneously cut 011 the supply of, steam to-the accumulator and the discharge conduit from the accumulator.

9. In a steam plant, in combination, a motor, a steam accumulator, means to supply steam to the motor, a supply conduit extending from said motor to said accumulator, a discharge conduit extending from said accumulator to said motor, means whereby at a given normal speed the steam flow through the supply and discharge conduits is out off while steam is permitted to fiow through the motor.

10. In a steam plant, in combination, a motor comprising a plurality of stages, an accumulator supplied with steam from a point ahead of one of the stages and delivering steam to a point ahead or another stage, means responsive to the speed of said motor to out off communication between the accumulator and motor at a given motor speed, means to open communication from said accumulator to said motor but preventing flow of steam into the accumulator at decreased speed, and means to open communication to permit flow of steam 'into said accumulator and cutting ofi flow of steam from said accumulator to said motor at increased speed. 11. In a steam plant, in combination, a motor'comprisinga plurality of stages, an

accumulator supplied ,with steam from a point ahead of one of the stages and deliver-' ing steam to a point ahead of another stage,

means to cut off communication between the accumulator and motor at a given speed, means to open communication irom sa1d accumulator to said motor but preventing How of steam into the accumulator at decreased speed,'and means to open communication to permit flow of steam into said accumulator and cutting off flow of steam from said accumulator to said motor at increased speed,

and a centrifugal governor responsive to the speed of the motor to control said means.

'12. In a steam plant, in combination, a

.motor comprisinga plurality'of stages, an

accumulator coupled in parallel to one or a more stages of the motor, automatic means responsive to the speed of'said motor to control passage oi? steam into andout of the While accumulator and a-clear uninterrupted pasmeans to, supply steam to said accumulatorf steam through said nozzles, said speed responsive means operating to cut 011' said flow at a given-normal speed of the turbine permitting steam to flow through the motor. j

14:. In a steam plant, in combination, a motor having a high pressure stage, an intermediate pressure stage and a low pressure stage, a first chamber between said high pressure stage and said intermediate stage,

a second chamber between said intermediate stage and said low pressure stage, an accumulator, a conduit between said first chamber and said accumulator, a throttle V valve in said conduit, a conduit between said second chamber and said accumulator, a throttle valve in the last mentioned conduit,

and means responsive to the speed of said motor to operatethe throttling valves.

15. In a steam plant, in combination, a. motor having a high pressure stage, an intermediate pressure.stage and a low pressure stage, a first chamber between said-high pressure stageand said intermediate stage, a second chamber between said intermediate stage and said lowpressure stage, an accumulator, a' conduit between said first chamber and said accumulator, a throttle valve in said conduit, a conduit between said second chamberand saidaccumulator, a

throttle valve in the last mentioned conduit, and means-responsive to the speed; of said motorand -operating' to hold both said throttling valves closed at a given speed, to

open the first-mentioned throttling valve when the speed of the motor. increases above said given speed and to open the secondmentioned throttling valve when the speed of the motor decreases below said given speed.

16. In a steam plant, in combination, a

motor having a, high pressure stage, an intermediate stage, a low pressure stage, a first chamber between said'high pressure stage and said intermediate stage, a secondchamber between sa1d intermediate stage and said low pressure stage, a separate chamber for supplying steam to said low pressure stage, an accumulator, a conduit between said firstchamber and said accumulator, a

throttle valve in said conduit, a passage for steam from said accumulator to said so arate chamber, a throttle valve to cont-r0 flow h hi 'e d p s ge ndf ean' re ive to thespeed of said moton'to'bpe'rate the throttling valves.

' ing to hold said throttling valve closed at aaccumulator to said motor,

17; In a steam plant, in combination, a source of steam, a motor,,an accumulator, a passage forsteam from said source to said accumulator, a throttling valve controllinga passage for steam from said a throttling valve in the last-mentioned passage, means to conduct steam from said source to said motor, means to supply steamto said source, means responsive to-the speed of said motor -operatsaid passage,

given speed, to open .the first-mentioned throttling valve when the speed of the motor increases above said given speed and to open the second-mentioned throttling v'alve when the speed of the motor decreases below said given speed, and means to diminish the supply of steam to said source when the speed of the motor rises above a high value. 0

18L In a steam plant, in combination, a source of steam, a motor, anaccumulator, a passage forsteam from said source to said predetermined accumulator, a throttling valve controlling said passage, a passage for steam from said accumulator to said motor, a throtthng valve in the last-mentioned passage, means to con- "duct steam ,from said source to said motor,

passage for steam from said source to said accumulator, a throttling valve controlling said passage, a passage'for steam from said accumulator to said motor, a throttling valve in the last-mentioned passage, means to conduct steam from said source to said motor, means to supply steam to said source, means responsive to the speed of said motor operating to hold both said throttling valves closed at a given speed, to open the firstmentioned throttling valve when the speed of the motor increases above said given speed and to open the second-mentioned throttling valve when the speed of the motor decreases below said given speed, a-clear uninterrupted passage for steam through the motor andmeans to diminish the supply of steam to said source when the speed of the motor rises above a predetermined value.

20. In a steam plant, in combination, a motor having a plurality of stages, a cham- -ber between two of said stages, a source of steam, an accumulator, a passage for steam from sald source to said accumulator, a

throttling valve controlling said'passage, a

passage for steam from said source to said motor, a throttling valve controlling the last-mentioned passage, a conduit for steam I 'it'rom said accumulator to said chamber, a throttling valve insaid conduit, and means responsive to the speed of said motor for controlling said throttling valves.

' 21. Infa steam plant, in combination, a motor having a plurality of stages, a chamber between two of said stages, a source of tthrottling valve controlling said passage, a passage for steam from said source to sai motor, a throttling valve controlling the last-mentioned passage, a conduit for steam from said accumulator to said chamber, a throttling valve in said conduit, and means responsive to the speed of said motor operating to hold the first-mentioned and third-- mentioned throttling valves closed at a given speed of the motor, to open the first-men- 'tioned throttle valve when the speed of the motor increases above said given speed and -steam, an accumulator, a passage for steam from said source to sand accumulator, a

to open the third-1nentioned throttling 'valve when the speed of the motor decreases below said given speed.

22. Ina steam plant, in combination, 'a

motor, an accumulator, a conduit to conduct steam from said motorto said accumulator,

'a conduit-to conduct steam from said accumulator to said motor and throttle valves [within and controlling each of said con:

duits, said conduits being the only conduitsv communicating between the accumulator and the motor, so that the motor may be substantially independent of pressure variations in said accumulator.

23. In a steam plant, in combination, a motor, an accumulator, a plurality of conduits connecting said accumulator with said motor, one of which conduits leads steam from said accumulator to said motor and one ofwhichconduits leads steam from said motor to said accumulator, and a throttle valve Within and controlling each of said econduits, said conduits being the only conduits communicating between the accumulator and the motor so that the motor may be substantially independent of variations of pressure in said accumulator.

24. In a steam plant, in combination, a

source of steam, a motor, an accumulator, a plurahty of conduits interconnecting said source, motor and accumulator, one of which conduitsleads steam from the source to the accumulator and one of which conduits leads steam from the accumulator tothe motor, and a throttle valve within each of the conduits interconnecting the accumulator with either the source or the motor so that the motor may be made substantially independent of variations of pressurein said accumulator.

25. In a steam motor plant, in combination, a motor having a plurality of stages lncludmg a low pressure stage, a source of steam, two parallel paths for steam from said source to said low pressure stage, one of said paths including an accumulator and means responsive to variations of load con, ditions in the motor plant to wholly cut off communication between said accumulator and said motor while the motor operates at a substantial value of balance of plant load. 26. In a steam motor plant, in combination, a motor, an accumulator, a plurality of conduits connecting said accumulator with said motor, one of which conduits leads steam from said accumulator to saidmotor and one of which conduits leads steam from said motor to said accumulator, throttling valves within and controlling each of said I conduits, said conduits being the only conduits communicating between the accumulator and the motor so that themotor may be substantially independent of variations of pressure in said accumulator andv means responsive to variations of load conditions in the motor plant to control said throttling valves and operating to wholly cut off communication through each, and all of said conduits between said accumulator and said 'motor and between said motor and said ac- "cumulator while the motor operates at a substantial value of balance of plant load.

In testimony whereof I aflix my signature.'

GEORG FORNERJ.

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