US1572962A - Steam-accumulator plant - Google Patents

Description

Feb. 16 1926..

J. RUTHS ET AL STEAM ACGUMULATOR PLANT k Filed Jan. 23 J 1925 2 Sheets-Sheet 1 [Ill anion? y U/ 'J' Aft'arneg 1 572,962 J. K. RUTHS ET AL STEAM AGCUMULATOR PLANT Filed Jan. 2 1925 2 Sheets-Sheet 2 In Ven 0115 V/ JS/ Attorney Patented Feb. 16, 1926.

UNITED STATES PATENT OFFICE. I

JOHANNES KARL RUTHS, 0F DJ'UR S H QLM, AND NILS PERSSON, OF STOCKHOLM, SWEDEN. ASSIGNORS TO AKTIEBOLAGET VAZPORACKUIVIIULIATOR, OF STOCKHOLM,

SWEDEN, A CORPORATION OF SWEDEN.

STEAM-ACCUMULATOR PLANT.

) Application filed January 23, 1925. Serial No. 4,343.

To a]? whom it may concern:

lie it known that we, Jornmxns KARL Burns and Nils PnnssoN, subjects of the King of Sweden, and residing in Djurshohn, Sweden, and Stockholm, Sweden, respectively, have invented certain nnv and useful Improvements in Steam-Accumulator Plants, of which the following is a specification.

()ur invention relates to steam plant-s wherein steam isbled from steam consumers and more particularly to steam plants equipped with accunmlators.

()ur invention also relates to steam plants wherein power machinery, especially turbines, operates in conjunction with a-fsteam aecuunilator and one object of the invention is to obtain a greater pressure drop than has hereto been possible in such power machinery. thereby obtaining a greater amount of work from process steam whereby the cost. of power is diminished and plant ef-- l'ieiency increased.

()ur invention further has for its object to provide a steam accumulator plant, wherein the back pressure or the extraction pressure of steam consumers. for example power machinery, such as turbines, is made imlependent of variations in the pressure prevailing in an accumulaton.

Previously known plants equipped with accumulators and in which steam is passed through a consumer such as a motor, for example, a turbine or a reciprocating engine in which power is extracted have been so arranged that the back pressure or extraction pressure of the consumer, that is to say,

. that pressure to which the steam for the low -is substantially the same and varies with the pressure in the accumulator, that the Workpressure consumers expands in th motor, is either always higher than the highest accumulator pressure, or substantially the same as that pressure, and variable there with.

Both these conditions are objectionable in that in the first case all the available power is not extracted from the steam and in the second case. where the extraction pressure ing of a consumer is hampered and the amount of power extracted in a motor is a function of the variable pressure in the accumulator. i

It is evident also that when the back pres-- sure of a motor varies continually in accordance with variations in the accumulator,.

that the regulation of the motor is difficult and as smooth an'operation will not be obtained as when the back pressure is constant.

In some instances it has been found, particularly in plants which use a large amount of low pressure steam and in which the peaks are relatively small as compared to the average steam consumption, that it is possible to extract a greater amount of power from process steam if this steam in a quantity up to that available in the high pressure line, can expand in the motor from the high pressure of the line from" which it is taken all the way down to the pressure at which the steam is eventually used for process work and have this complete expansion irrespective of variations occurring in accumulatorpressure while the surplus of steam generated over the momentary consumption is led in a path parallel to the path of steam passing through the motor to the accumulator from whichsteam is led to low pressure consumers when the demand of these consumers is greater than the supply afforded. by the motor.

The present invention proi'ides means wherebythe greater extraction of power in the motor as above outlined is accomplished and, further, obtains this result by means of a simplified arrangement of regulating ele ments. As pointed out in our co-pending application Serial No. 574,089 filed July 10th, 1922, to which this application is to be considered as relating back for all common subject matter, and in which. the prescut invention is disclosed, the majority of plants wherein the pressure in the motor drops all the way from the high pressure tothe low pressure lines a regulating mechanism is necessary wherein the regulation is a function of the pressure before and beto most of the arrangements described have a minimum of four regulating elements; one to control the flow of steam into the motor, one to'control the flow of steam .from

the motor, one to control the flow of steam through a line connecting the boilers with the accumulator in parallelwith the motor, and a reducing valve placed between the accumula-tor and the low press'ure consumers and so arranged that the said reducing valve also lies between the aecmnulator and the point of connection of the extraction or-back pressure line to the low pressure line. In

. the present invcntionthe arrangement is simplified by, causing the pressure behind a the motor, to operatethe valve in the parallelly disposed steam linein such a manner that one of the regulating elements, controlling the flow through the turbine can be omitted. ,The invention will be described more fully inconnection with the accompanying drawings in which:

.Fig. 1 shows a. plant according to the present invention .prow' ided with a back pressure turbine and without high pressure consumers; i

Fig.2 shows a plant similar to- Fig. 1 except that high pressure consumers are suppliedwith steam directly from the boiler;

Fig. '3 shows a plant comprising asingleextractionlturbiner Fig. 4 shows a plant comprising a double extraction turbine and also having other regulating arrangements of use in certain plants,.and-, Fig. 5 isa section taken partly on line 55,Fig.4.

Referring to Fig. 1, 10 represents a steam generator. from which steam is conducted through the conduit 11, partly through conduit 12 to themotor '13 which may be a turbine, and, generator 14 connected with the electric circuit 15, to supply power thercto and operating inparallel with a second electric.

generator 16', driven for example by a waterturbi'ne the arrangement being such that the-power generated 111 the. motor .13 can.

pressure in front ot' the same and decreases ..;\inde1' normal conditions all be transferred into electrical energy in the generatoralel.

and utilized in the circuit 15. The steam after passing' 'through the motor 13 is conducted through the back pressure connectionlT to low pressure conduit 18 from which steamis supplied to low pressure C(lll". sumers 19 whichm'ay he dryers, heaters. or anyother consumers using low pressure steam. c

Anotherv part of the steam generated is conducted through eonduitZO inparallelto the motor and is delivered to the accumulatcrjconduit :21 to which an acrumulatrn' 22 is connected, preferably. in parallel to con duit 21. 23 and 24 designate check valves which control the flow of ste m into and.

sure conduit.

as, -illustrated,- drivingv a -Areducing valve 25is placed between'accumulator conduit 21 and low pressure condu'it 18 and controls the flow of steam fromthe accumulator conduit to the low pres- This reducing valve is so placed that steam can expand in the motor all the way down tothe pressure in conduit '18, that is, the'connection between back pressure conduit 17 and conduit 18 is made at a point which is behind the reducing valve 25. In other words, reducing valve 25 is placed between the accumulator and the point of connection of the back pressure line to the low pressure conduit of the steam plant. i

W'ith this arrangement it is'evidcnt that in order to prevent more steam from passing throng-lithe motor than-is needed in the low pressure line a regulation must be supplied which will limit the amountofsteam pass ing through the motor. That is, the motor might at certain times suck in more steam than the low pressure consumers'need in which casethe flow of steam through the motor must be limited. This regulation is accon'ipl'ished. in the followingmanner:

A; valve 26 is provided in the conduit 20 and is controlled by the pressure in conduit 17 in such a manner that an" increase of pressure tends to operr the valve and a decrease of pressure tends to close the same. This valve'opens-wh'en the pressure in conduit 17, and consequently conduit 18, increases above a predetermined value and closes, when the pressure falls below a predetermined value. This valve'alone, however, would not properly regulate the flow of steam to and past the motor but it is also necessary to have the valve 27 in conduit 12 which controls the flow of steam to the motor. Valve 27 is also a pressure responsive valve. It opens when the actuating pressure has risen above a predetermined value. and closes when the pressure has fallen below a p redetermined value. Between these two predetermined values it increases 7 the steam flow to the motor upon a rise of the flow when the steam pressure falls.

.Such a valve may he termed an overflow valve.

The operation of the plant is as follows:

-Suppose the pressure in conduit. 18 rises,-

duc eitherto decreased. (JOIlSlll'llPlllOll iu-the .low "pressure consumers or an increase of pressure in conduit .18 thusu'eturuiug the plant to a state (if-equilibrium.

Suppose the pressure in conduit 18 decreases due for example to increased cousumption of coiisumers 19. The consequent decrease of pressure causes a closing of valve 26 which in turn increases the pressure in conduit 11, thereby causing an opening-t valve 27 so that more steam passes through the motor. If, despite this increased supply: of steam from the motor to the low pressure line, the quantity of steam supplied to the low pressure consumers is insutiicieut as indicated by low pressure in conduit 18. *alve 25 opens and steam passes from the accumulator to the low pressure line.

Suppose the pressure in conduit 11 increases. This causes an increased .tlow of steam through valve 27, thereby causing a greater flow through the motor to the low pressure line 18. I Should the supply of steam to the low pressure consumers then be greater than what is needed the pressure would rise inconduit 18 and valve 2b will open more or less in turn causing valve 27 to be closed more or less, whereby less steam is passed through the motor and a greater quantity by-passed to the accumulator.

Although only a few possibilities in pressure changes in the plant, and the consequcnt reaction of the plant have been pointed out, it is clear that the regulation will take care of any conditions and that a constant pressure can be obtained in the boilers and in the consumer conduit while at the same time a large pressure drop in the motor is possible.

The pressure in the accumulator may vary between the pressure of conduit 18 which may, for example be 20 lbs. gage to the pressure of conduit 11 which may, for ex ample, be 150 lbs. The pressure in the accun'iulator is in proportion; to the amount of steam stored. Despite the great variations of the accumulator the back pressure of the motor will be'constant at 20 lbs. gage.

Conduit 29 with reducing valve 2'.) therein is normally inoperative and comes in operation only when, as might infrequently occur, the accumulator becomes fully discharged when valve opens to admit high fpressure steam direct to the low pressure consumers, so that steam will not wholly be cut from the low pressure COHSHII'IOI'S.

Tait-represents a speed governor operating wear down the supply of steam to the turbine in case the speed should for some rcason unduly: rise above normal.

Valve 27 not alone serves the purpose of acting as an auxiliary to-valve 26 in opera- "tion but also maintains a constant boiler those skilled in the art, only so much has been shown as is necessary to a toll understanding o'fthe invention, many pzlrts,1ieoessary or desirable being omitted for sake of clearness. The parts may be changed with ii? the scope of the invention. The valves are only diagrammatically illustrated, it being understood that any alves performing the functions ascribed to those illustrated may be used.

Fig. 2 shows a plant similar in all respects to Fig. 1- escept that high pressure consumers 30 are shown as supplied with steam ahead of valve 27. The operation of this plant is the same as that of Fig. 1. The

valv 27 serves the additional purpose here that it maintains a constant pressure for the high pressure consumers.

In operation, suppose the pressure in high pressure line 11 rises somewhat due for example to decreased consumption of the high pressure consumers. The increased pressure operates to increase the opening of the valve 27, so that more steam flows through the turbine. It then there is too much steam in conduit 18, the pressure therein will rise and the opening through valve 26 will be increased. This in turn decreases the pressure in conduit 11. whereby valve 27 is closed somewhat, and the plant brought into a state of equilibrium.

Equalization is brought about in the reverse manner, it the pressure in conduit 11 should fall, the operation of the plant: being readily apparent.

Fig. 8 shows a plant wherein a single extraction condensing turbine is used. In this case it is not necessary that the electric generator driven by the turbine be coupled in parallel with other electric generators. in this case the turbine. is regulated so that it produces the exact amount of electrical encrgy needed in the circuit 15. 31 represents the condei'lscr and 32 represents a speed responsive device coi'itrolling valve 33 and op erating to control the supply of steam to the low pressure stages of the turbine at normal speed.

In operation. suppose the consumption of electrical energy lINfl'titSGE. the number of revolutions of the turbo-generator set will then decrease somewhat and the normallv operating speed responsive governor 32 will operate to increase the flow of steam to the low pressure section L 01 the llpon opening of the valve 3; the turbine would speed up so that the speed of the generator is constant. but this causes drop oi pressure in the low pressure line 18. A drop of pressure in conduit l8 may operate as in previouslydescribed modifications to decrease the flow of steam through the valve 26. which in turn causes an increase ot' pressure in conduit 11. Increase of pressure in conduit 11 causes auincreased fiowof steam through valve 27, and high pressure section H so that the pressure in conduit l8 is returbine;

tained at a normal value. Thus a greater quantity of steam flows through the motor and less is by-passed to the accumulator.

It valve 26 is already closed when the pressure drops in conduit 18 value will open and admit steam to the low pressure consumers.

Further it the low pressure section of the turbine requires more steam than is supplied by the high pressure section, the deficiency will be'supplied fromv the accumulator through conduits 21, 18 and 17.

Again, for example, suppose that the pressure in conduit 11 increases, valve 27 will then open wider and more steam will pass through the high pressure section H of the turbine. This would in mostainstances increase the speed of the turbine inwvhich arms oil which operate the valves.

case governor '32 will operate to decrease th'e\ flow of steam through valve It the low pressure consumers can not/take care of the additional steam supply, valve'26w1ll be opened and valve 27 regulated so that again more steam is by-passed to the accumulator and less flows through the high pressure section of the motor.

Figs; 4 and 5 show a plant comprising a double extraction condensing turbine. 'The turbine comprises three sections, a' high pressure section H an intermediate M and a lowpressure section L. Both the high pressure section and the intermediate section are shown as being controlled by multiple nozzle regulation, otherwise known as partial regu ation. This is indicated generally by reibrentp characters and respectively. This type of regulation comprises a series of valves, each controlling a group of nozzles, some of which arefindicated at 34, 35, 36 in Fig.- 5, and operated successively by means of cams .37 attached to a rocker shaft 38 and actuating rocker This type of regulation has distinct advantages over the single throttling .valve since there is no appreciable drop ofpressure through the valves of the partial regulation and thus theinitial pressure of the turbine stage is maintained high and constant, a factor of great'advantage inturhine efiiciency. i

'Iheregulation of the'turbine shown in Figs; 4 'and- 5 may be briefly summarized as follows: 1 i

The low pressure stages L are controlled by speed at normal values of the same. The

intermediate stages M are controlled by the .,trols the flow of steam parallel to one or pressure ahead of the same, that is in thefirst supply chamber, b high value of speed'and by low value 0 speed. The high ressu're wheel is controlled by pressureahead of the same, in the instance shown by boilerjpressure and and low values ters 45.

the motor, since this is the most practical,

it will be understood that other types of consumers may be used. High pressure consumers 41 may or may not be connected to reeeivesteam from conduit 40, depending' on the design of the particular plant.

Steam after passing through the high pressure stage H enters supply chamber 42 to which is connected extraction conduit 43 tapping steam into conduit 44, here shown as a digester line supplying steam to diges- Conduit 44 corresponds somewhat to conduit 11 of the previous modifications since, as will be seen, if the boilers were,

connected to conduit 44 and the high pressure wheel H omitted from the turbine the plant is thesame as that of Fig 3. The steam supply to the intermediate stage M from the first supply chamber 42 is controlled by valves 60 and the steam after passing through the intermediate stages enters the second supply chamber 47 to which-"is connected extraction conduit 17 tapping steam into low pressure conduit 18 from which low pressure consumers as, for

example the drying cylinders of paper machines 19, are connected. 21, as before, represents the accumulator conduit to which accumulator 22 is connected. Between conduits 44 and 21-cxtend the two conduits 20 and 28 containing the valves 26 and 29, which in practice are united into one conduit controlled by one valve responsive to a plurality of impulsesaccording to the disclosure in patent application Ser. No.

-604,111 filed Nov. 29, 1922, Patent No.

1,527,275, this construction being however, too detailed to show-in this application and being such thatone skilled in the art can apply the same to the present showing with proper results. In the present application I am describing the valves as separate although they may be either separate or combined. Regulating member 29 operates as in the previous modifications, being normally inoperative, and operating to admit steam 'from conduit 44 to conduits 21 and 18 when the accumulator is discharged. Regulating member 26, as previously, conmore motors. in this figure the motors being the intermedlate and low pressure stages M and L. Reducing valve 25 is placed be-v tween conduits 18 and 21 and conduits 20 and 17 are so related to these conduits that conduit 20is connected to the low pressure.

conduit 182l ahead of ieolucingv valve 25 r and the pressure is maintained substantial and conduit 17 behind valve 25, whereby the steam in supply chamber 47 is substantially the same as in conduit 18. y

The regulation is such that a constant pressure is maintained in conduits 18, 10 and 44 and consequently in supply chambers 42 and 4:7. W'ith a constant vacuum in condenser 31, it is thus seen that all turbine pressures are kept constant whereby the utmost eiiiciency of'the turbine may be obtained while, at the same time the plant has all thewell known advantages of the Ruths type of accumulator, including constant steam generation and ability to supply large momentary peaks.

If, for example, a peak occurs in-condult 44, say, for example, in a digester room,

the pressure decreases momentarilly in supply chamber 42. Pressure in chamber 4 then acts through pipe 48 to operate pisto 49 which, through the agency of slide valve S and other mechanism known per se operates to close some or all of the valves of regulator 60 so that. less steam passes to the intermediate stages of the turbine ly constant in chamber 12. By known regulation this canbe accomplished to within a variation of one pound pressure. The decrease inv steam supply to intermediate stages M would probably in most cases lead to de- .crease the\speed of the turbine whereby speed governor 50 will through rods 51, 52 and 53 and crank arms 54 and 55 cause valve 56 to increase its opening thereby admitting more steam to low'pressure stage L. If this abstraction of steam from supply chamber 47 causes a decrease of pressure in conduit 18 below normal, it being assumed that valve 26 isclosed, valve 25 will open and admit steam from the accumulator to conduit 18. v

Suppose the pressure rises in conduit 40. The increasing pressure will act through conduit 57 to move piston 58 downwardly causing a movement of slide valve S to change the liquid supply to servo-motor K which rotates rocker shaft 38 in clockwise direction so that moreadmission valves are opened and more steam passes through the high pressure stage H. With the resultant increase ofpressure in supply chamber 42 and due to the increased flow through high pressure stage II, there occurs simultaneous 1y an increased supply of steam through the intermediate section M and decreasing of. opening oi valve 56 due to mechanisms 60 and 50 in manner above described. This in turn increases the pressure in supply chamber 47 whereby the pressure in conduits 17 and 18 likewise rises, provided, of course, that the low pressure consumers do not simultaneously ncrease their steam demand so that the pressure remains normal. With an unchanged condition of consumption in the low pressure conduits increased pressure in conduit 18 occurs which causes a movement of regulating member 26 to cause a greater flow of steam through conduit 20 to the accumulator. The pressure in supply chamber 42 then lowers which causes a do crease of steam passing through the intermediate stages and thus the flow of steam is shifted from the lower pressure extraction conduit to the higher and the load. must consequently again shift back to the low pressure stages. The surplus of steam is thus mechanically sent into the accumulator. Although in following the stages through it seems that the many steps might 1 cause lag in operation, the action is in practice practically instantaneous as has been demonstrated by an actual construction made according to this plan. It is not to be expected that variations will occur in the conduit 40 when no consumer is thereto attached, but the variations oc'cur further down in the system where the regulation re-v quires fewer steps.

The speed responsive device also operates at high and low values of speed as follows: f

It the speed increases to such an extent that valve 56 is completely closedand the speed is still too high the steps on rods and 76 engage the respective levers 77 and 78 which control movement of slide valves S, and S and operate to close valves 50 and 60. On the other hand, it the speed of the turbine decreases to an excessively low value the stops 71 on rods 75 and 76 will be engaged to open valves 50 and 60.

. From the above description it is evident that wherever fluctuations occur they will be automatically equalized and the turbine can have an expansion all theway down to the low pressure consumers at all times and is independent of variations of pressure occurring in the accumulator which may be very great.

What we claim is:

1. In a steam plant, a primary source of steam supply, a motor, a secondary source of steam supply, a consumer, a conduit to load steam from said motor to said consumer. a conduit to lead steam frolnsaid secondary source of steam supply to said consumer, means to conduct steam in a path parallel to said motor from said primary source of steam supply tothe second mentioned conduit and means to control the flow through the parallel path operated by changes of pressure in the first nicntioned conduit.

2. In a stcaui plant in combination, a steam generator, a turbine of the double extraction type connected to receive steam from said generator, said turbine comprisiug a high pressure section, m intermct ate pressure section and a low pressure section,

, said turbine, an intermediate pressure conduit and adapted. to open when the last "duit and deliver the same to said low accumulator to said loivpressnre conduit, a" reducing valve to c'ontrollthe flow of steam duit, a first extraction COIldlllii'COIlllGCilBd to receive steam from said high pressure section and deliver the same to said intermediate pressure conduit, a consumer connected to receive steam from said intern1e-' diate pressure conduit, a low pressure conduit, a second extraction conduit connected to receive steam from said-intermediate pressure section and deliver the'same to said low pressure conduit, aconsumer connected to receive steam from said low pressure conduit, an acciunulator, an accumulator conduit connected therewith, a reducing valve receiving steam from said accumulator conduit and delivering steam to said low pressure conduit, a' connectin conduit extending between said interme iate pressure conduit. and said accumulator conduit and a valve in said connecting conduit operated by the pressure in the second extraction conmentioned pressure rises above a predetermined value. V

3.121 a steam plant, in combination, a source of steam, an extraction motor adapted to receive steam therefrom, a low pressure conduit, anextraction conduit connect" ed to receive steam from said motor and deliver the same to said low pressxirecon-v duit,.a consumerconnected to receive steam from said low pressure conduit, anaccumulater, an accumulator conduit connected therewith, a reducing valve connected to receive steam from said accnmulatorconressure conduit, a conduit leading steam rom said source of steam to said accumulator and means to control the flow of steam through .the last mentioned conduit in responseto pressure in. said extraction conduit. 7

, 4.111 a steam plant, in combination, .a steaxngenerator, a consumer, adapted to receive steamtherefrom, a low pressure conduit, :1 blceder conduit lcadingfrom said consumer to said low pressure conduit, a

consumer adapted to receive steam from said low, pressure conduit, an .accumulator, ja conduitfadapted to flead steam from said through. the last mentioned conduit, a conduit leading steam from said generatorfto said accumulator, a valve in the last mentioned conduit and means to control said valve operated in response to pressure in said bleeder conduit.

5. Ina steam plant, in combination, a steam generator, :1. consumer, two parallel paths for steam from said generator to said consumer, the one path containing a reducing valve and having nnaccumulator connected thereto between said reducing valve 'dnit, I conduit connected therewith, a reducmg valve receiving steam from saidaccumulabetween said motor and said conduithaving a point of connection with said conduit such that said reducing valve lies between said point of connection and said accumulator, a conduit leading steam from said generator to said accumulator, a valve in the last mentioned conduit and means to operate said valve responsive to changes of pressurein said connection.

7. In a steam plant, in combination, a primary source of steam supply, a consumer adapted to receive steam therefrom, a low pressure conduit, a bleeder conduit leading from said consumer to said low pressure conduit, :1 consumer adapted to receive steam from said 10w pressure conduit, a secondary source of steam supply,a secondary' supply conduit adapted to conduct steam from said secondary source of steam supply to said low pressure conduit, a reducing valve to control flow of 1 steam from said secondary supply conduit to said low respressure conduit, a motor-connected to receive steam from said generator, at low pressure conduit, a conduit connected to receive steam from said motor and delii 'c r the same to said low pressure conan accumulator, an accumulator tor conduit and delivering the same to said 'lo\v"pressure conduit, means to conduct steam from said generator to said accumulator .anda valve controlling the last mentioned mcuns and operat/cd by the pressure in the conduit receiving steam from the motor. i

9. in a steam plant, in combination, a source of steam, a motor connected to receiv-c steam "from said sonce, regulating means to control. the flow "of steam to said motor operated by the pressure of the steam supplied thereto, a low pressure con- :umeeee' i '7 duit, a connection for flow of steam from Mid accumulator parallel to saidmotor said motor to said low pressur, conduit, and reguletirnr means controlling the last; g; consumer connected to receive s cam from mentioned means and operated in response said low pressure conduit, an accumulator, to pressure in snid connection.

v5 an accumulator conduit connected therewith, 1'11 testimony whereof we hereunto aflix a reducing valve receiving steam from said our'signatures. accumulator conduit: and delivering the i same to said low pressure conduit, means JOHANNES KARL RUTHS. to conduct steam from said source of steam NILS PERSSON.

Images