US1060354A

US1060354A - Governing mechanism for mixed-pressure turbines.

Info

Publication number: US1060354A
Authority: US
Inventors: Paul Mortier
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1911-07-05
Filing date: 1911-07-05
Publication date: 1913-04-29
Anticipated expiration: 1930-04-29

Description

P. MRTIER.

GOVERNING MECHANISM POR MIXED PRESSURE TURBINES.

APPLICATION FILED JULY 5,1911.

1,060,354 Patented A111129, 1913.

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P. MORTIBR.

GOVERN-ING MBGHANISM FOR MIXED PRESSURE TURBINBS.'

APPLICATION FILED JULY 5, 1911.

1,060,354, y Patented Apr.29,1913.

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and useful `Improvements in UNITED `STATES PATENT OFFICE.

FRANCE, ASSIGNOR TQ GENERAL ELECTRIC COMPANY, A. CORPORATION 0F NEW YORK.

GovEamNe Mncnamsm For. MIXED-PRESSURE TURBINES.

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To all wiz-0m t may concern .Be it known that I, PAUL MoRTIER, a citizen of the French Republic, residing at Paris, France, have invented certain new Governing Mechanism for Mixed-'Pressure Turbines, of which the vfollowing is a specification. y The present invention relates to'governing mechanismfor that type of prime mover commonly known as a mixed pressure turbine. Such a turbine is arranged to be sup-V plied withsteam or other elastic fluid of low pressure for normal operation and to be supplied with steam-or other4 elastic fluid of higher pressure when the low pressure source fails or is insuiicient Ato supply the demands of the turbine. The low pressure source is depended upon in so far as it is available tothe exclusion -of the high pressure source because it is less expensive. Y A mixed pressure turbine should be so ar-i ranged that it can automatically pass from one supply of Huid to the other without change in speed or in the power delivered by the shaft taking place. This is of prime importance where the turbine is arranged to drive an alternating currentgenerator which is connected in parallel with other generators. It is necessary therefore that the governing adapted, without change. of speed taking place and regardless of the respective amounts of fluid supplied by the different sources, to constantly control the admission of fluid to the turbine so as to maintain the speed constant within the limits ordinarily permitted between no load and full load conditions. It is further necessary in order to attain the best results that the governing mechanism shall regulate the participation of each of the twoiluids in the production of power, taking into account the available quantity of the low pressure fluid, z'. e., the

less costly fluid.

My invention has for its object to provide a governing mechanism of improved construction for a mixed pressure turbine, said mechanism being of the type which comprises the feature of putting two obturators in series at the point of entrance of each of said Hummm hmmm., M J 1 1 ators being operated or controlled by a 'tachometer or speed governor and the other being controlled or operated by a manometric Specication of Letters Patent. 4Application led July 5, 1911.

mechanism ofthe turbine be Serial No. 636,900.

or other device responsive to th pressure of the low pressure source of liuid supply. The obturators controlled by the speed governor are so arranged that they are moved toward and away from their seats or closed positions slmultaneously to regulate the total flow of the two fluids. On the other hand the obturators controlled by the pressure responsive device are so arranged that they control their ports in an opposite sense. That is to say, one obturator opens its port or ports while thev other closes its port or ports. As a result of this, the high pressure furnish only that. portion of the necessary Huid which the low pressure cannot supply, it being understood, however, that the total volume ot' motive fluid entering the turbine is subject to the control of the speed 'governor. To state the matter in another'way, two primary obturators are simultaneously controlled or movedlby the governor in one and the same direction and two secondary obturators located in 'series with and in .ad.

`Vance of the first areso arranged and connected that when one opens the other closes, the action of the secondary obturators being sensitive to "variations in pressure of the low pressure source.

In the accompanying drawings which are illustrative of my invention, Figure 1 is a diagrammatic view of a portion ofone of my improved governing mechanisms; Fig. 2 is a diagrammatic view also illustrative of the invention; Fig. 3 is a detail view of one .form of servomotor; and Fig.4 is a sectional view of part of a governing mechanism.

1 indicates a high pressure steam chest to which steam is admittedv from a boiler or other source by. the conduit 2. Located within the chest is a` gridiron valve 3 arranged to slide back and forth.over the ports 4.' This valve or obturator is actuated by a device responsive to the pressure variations` of the low pressure source of supply to be described later. Motion from this device is transmitted to the valve by the rod 5. It willbe noted that the bridge pieces 6 of the valve are differently spaced Yand .also gradually increase in width from the bottom to the top so that as the valve rises, ne to the action of the pressure device, the first or bottom port will open, then' the one above and so on. In the downward movement of the valve the upper port closes first, then the Patented Apr. 29, 1913.

source will soV one nextbelow, etc. The chest is also provided with

chambers

7, 8 and 9 which receive steam under the control of the gridiron or Slide valve 3. from these chambers or other discharging control of obturators or

valves

10, 11 and 12. These are strung on the rod 13 that yis actuated by means of the speed governor or by means under its control. On the rod are collars 14 so -spaced with respect to 'the valves that as the rod 13 moves upward it opens the valve 1() and finally the valve 12. In closing the reverse order is followed, valve 12 closes first, thenV the valve 11 and finally the valve 10. It is to be noted that valve 3 opens' the lowto the turbine nozzles devices is under the est port first, whereas the ro'd 13opens the 4In the chestv is an ,upper valve first.

15 indicates a low pressure steam chest to which steam is admitted from the exhaust pipe of another engine, from a receiver, regenerator or other source bythe conduit 16. obturator or gridiron valve 17 lwhich is 4mounted on the rod 18 that is or may be a part of the rod 5 and is arranged to move 1n unison therewith in response to a device sensitive to changes in pressure of the low pressure source to be referred to later. The valve 17 is of the same general character 'as the valve 3 as are also the ports 19. Itis, however, arranged with respect to its ports. hat is to say, as the valve moves upward it first closes the'lower port., then the one .next above and so on, whereas an upward, movement of the high pressure valve opens the lowest port, then the` next and so on.

In the chest are

chambers

20, 21 and 22 to which low pressure steam is admitted under the Control of the valve 17. As shown,

- all of these chambers are open to the steam supply, whereas the

high pressure chambers

7, 8 and 9 are cut o. The low pressure ports V19 are. soiproportioned as to ad-` mit the proper amountv of steam for low pressure operation when the valve is in the open position of supply is sufficient. The outlet of steam from the chambers to the turbine is controlled by obturators or

valves

23, 24 and 25. These valves are mounted on the. rod 26 which may form a continuation .of the rod 13 and move in unison therewith. `The rod is provided with collars 27 that are suitably positioned with respect to the valves to open and close them successively. The valves are of course larger than the high pressure .valves owing to the increased volume of The passageof steam.

first, then the valve 11V oppositely y and the low pressure sourcev moved by a tachometer or speed responsive device, or by means controlled thereby.

The ports of the obturators are of such dimensions that the power developed in the turbine due to the amount of low pressure steam passing through one `of the-ports 19 to the turbine is equal to the power developed in the Vturbine due to the amount of steam passing through one of the ports 4. Of course, when the amount of steam received from the low pressure source is only a portion of the total bine, this proportional 'variation is produced" only on the corresponding portion of Vthe high pressure opening which comprises,

in addition to this variable part, a constant opening corresponding to the portion of the steam supply which is required from theA high pressure source.

Consequently, whatever be the ratio of the valve openings imposed by the manometric device, the power of the turbine will not change when the obturators or

slide valves

3 and 17 are moved under the action of said device.

It is to be noted that whatever the relation of the said valve openings, the tachometer or speed governor will simultaneously close ori-open the

admission valves

10 and 23;

llrand

24, and 12 and 25, according to the variations of speed of the turbine. It will further be noted that there will be what may be termed a composition regulation (meaning a regulation of the proportions of the two uids) and a quantity regulation (meaning the total quant-ity or amount of fluid supplied to the turbine), each taking place 'independently but `coperating to govern the turbine. The composition regurequired by the turlation will be determined by the available amounts of low pressure steam due to the pressure responsive device and the quantity regulation will be determined by the power requirements as established by the speed governor. y

The foregoing description has beendirected especially to a turbine having both high and low ressure nozzles-or other discharging devices for supplying wheel vbuckets or bladesthat are cut into and out of service successively. The following 'description will be directed to an arrangement in which low pressure steam is admitted to the low pressure ortion of the turbine under the control o a throttle valve means, said steam after passing the valve 'means having access to all the nozzles or other fluid discharging'devices in the low pressure portion of the machine.

Referring now to Fig. 2,34 indicates a high pressure steam chest having 'passages leading therefrom to nozzles 35 whichV may be divergent or non-divergent in character as the operating conditions require." These nozzles discharge steam at a suitable velocity and pressure agalnst the buckets or ios l yie y es

Vmano-metric device la cylinder 51 to which steam is diret, then the blades 36 on a rotor 37. The passages are provided with

valves

38, 39, 40 and 41 which for convenience will be vtermed primary valves because they 4act on the steam rst. Of these valves 38 opens first and closes last. The passages are also provided with

valves

42, 43, 44 and 45 which for convenience will be called secondary valves because they act on the steam after the primary valves. Of these valves 42 opens first on an increasing load and closes last on a decreasing load. The primary valves are sensitive to pressure varlations in the 10W pressure source and the secondary valves to changes in speed of the rotor.-

A46 indicates the low pressure valve chest and mounted therein vis a primary throttle valve 47 which first acts on the steam received from the low pressure source by the conduit- 48, and a secondary throttle valve 49 that acts on the steam after it passes the valve 47. Steam is conveyed from the low pressure chest to the nozzles or other fluid discharging devices and to buckets or blades of the low pressure portion ofthe turbine by the conduit 50. The primary low pressure valve 47 and the prlmary

high pressure valves

38, 39, 40 and 4l-are actuated by a of any suitable construction. In the present instance it comprises admitted from the low pressure source by the conduit 52.' Within the cylinder is a piston 53 whose under side is exposed to the pis-sure ofthe low pressure steam. The upper side ofthe piston is exposed to atmospheric pressure and isor may be weighted by a spring 54.- The piston is connected to the primary low pressure valve 47 by the rod 55. Pivotally connected to the rod' by a fork and pin is a lever 56 pivoted at 57. The right hand end ofthe lever is connected by a rod to the rack 58, the latter meshi with a pinion 59 on the rock-shaft 60. n the shaft are mounted the primaryhigh pressure valves 38 to 41, inclusive, they valve 38 opening valve 39 and so on. As a result of the mechanism described, it will be seen that all of the. primary valves are mo ved by the manometric device.

61 indicates a tachometer or speed .governor mounted on the shaft 62 that is driven by the rotor 37. The connection between the rotor shaft and the-'governor shaft may be of any suitable form.

63 indicates a lever that is pivoted at 64 and is actuated by the sliding collar of the governor. To the lever is pivoted the rod connected with the secondary low pressure valve 49. 65 indicates a lever pivoted at 66 and actuated by the collar of the speed governor. To the lever is pivotally secureda rod that act-uates the rack 67 which in turn meshes 4with a pinion 68 mounted on the rockshat 69,l the latter openlng and closing the secondary high pressure valves 42 to 45 successively, the valve 42 opening lirst, then the valve 43 and so on.

Y In connection with the tachometer and its obturators or valves and the manometric 'device and its obt-urators or valves any ordinary yform of servo-motor may be employed `to relieve the load thereon, said motor -being actuated by steam, hydraulic, electric or other power. Both the tachometerand manometric device may be of any suitable form or construction as bestsuits the requirements in any given case.

In Fig. 3 is shown a suitable servo-motorl operated. hydraulically. It comprises a piston 3l and its cylinder and a pilot valve 32 to which is attached a rod 33 that may be actuated by the -speed governor or by the pressure responsive device. The rod of the directly through a cam and lever, as shown in Fig. 4. The main valve of such an apparatus is to relicvethe speed governor and pressure, responsive device of a large amount of work whereby they can be made more sensitive.

In Fig. 4 is shown a suitable arrangement of the valves for the high pressure portion of the turbine. 30 indicates the high pressuresteam chest and 38 one of theprimary valves. This valve is4 provided with an upright stem havinga` collar at the top. Engaging with the collar is a pivoted lever 70,

on the cam 71. l are mounted oni;J shaft which is actuated by a servo-motor under the control'of the toclose thc valve 38 when permitted to do so by the lever 70.. 42 indicates one of a ynumber of secondary valves which is vided with an upright stem having a collar at thetop that engages with a pivoted lever in turn is moved by aservo-motor under the control of the speed governor 61. A sp1-invr 75 servesto close the valve when permitted to do so'by the cam 74.

Assuming a suitable supply of low pressure steam and constant load, the operation of my improved mechanism is as follows, referring particularly to Fig. 2: Low pressure steam enters passes the

Valves

47 and 49, the valve 47 being responsive to the pressure of the low pressure source due tothe manometric de- `vice, and valve 49 being responsive to the loadon the turbine due to the action of the tachome'ter 61. The valves 38 to 41 will occupy positions determined by the manometric device and valves 42 to 45 will occupy positions due to the tachometer. constant load, assuming the low pressure supply to be sufficient, the speed governor keeps the valve 49 open by an amount suiiipiston 31 may actuate a valve directly or in-v the free end of which has a rollerv that rides 4 The cams for all the valves' manometric device. A spring 72 is arranged' pro- For anyA 73. The lever 1s actuated by a eam74 which by the conduit48 and sages cient to satisfy the load on the turbine, and also keeps one or more of the high pressure valves 42 to 45 open. On the other hand, the pressure responsive device keeps the valve y47 wide open and closes all of the valves 38 to 41. -If now the pressure of the low pressure source of supply d ecreases, the piston 53 will descend carrying with it the low pressure throttle valve 47 This same action working through the lever-56, rack 58, gear 59 and rock-shaft 60 will cause one or more of the Valves 38 to 41 to open admitting high pressure steam to one or more of the pasleading to the nozzles. The Valves are opened in the following order: 38 rst, then 39 and afterward 40 and 41. The reduction in the supply of low pressure steam requires that the speed governor shall open one or more of the secondary high pressure valves 42 Vto 45v inclusive and also close the secondary low pressure valve 49 by a proper amount. bine will remain the same but instead of receiving' low pressure steam only, it will be driven by a mixturel of. high and low pressure steam, the high pressure or more costly steam supplying only thatportion of the total energy which the low pressure cannot. The main difference between Figs. 1 and 2 Aresides in the fact that whereas in the former case the low pressure steam is admitted by successively operating valves to each nozzle or 'group of nozzles, in the latter case the admission is simultaneous to all of said nozzles but the total amount is regulated by throttling.

. The pressure responsive device and speed governor shown in Fig. v2 can obviously be used to actuatethe'distributers, obturators or valves of'the other figures. So also can the servomotor of Fig. 8.

It should be noted that the valve means controlled by the speed governor operate at once and in the same sense; that is. tosay,

source is deficient for a given load, t-he governor simultaneously opens passages to each vapor on the VVhigh and low pressure sides which could,

if they were effectively supplied (in the absence of apparatus contro sosure device), furnish in the 'form of lng h or low pressure steam, an identical quantity of energy which isequal, for a single flui to the total quantity necessary.

It should be further noted that 'the` valve means controlled 'by the pressure device should divide the work between the two fluids by reason of the pressure which is available in the low pressure source, only requiring the aid of the high pressure source when the supply from the low A pressure For this reason the valve means responsive to the low pressure source should, without taking into account the real load on theturbine', present a total opening for the two fluids such that the power fur- The power delivered by the tur-x ratusshownis only nished would be equal to the maximum power of the turbine, if the openings were effectively utilized, instead ofbeing in part controlled by the action of the valve means controlled by the governor.

At full load the valve 49 is -wide open and consequently the valve 47 begins to reduce the energy as soon as it begins its closing movement. On the contrary at light load the valve 49 is`only partly open producing the throttling of the steam necessary to the reduction of power. Consequently, if the valve 47 closes, its effect upon the energy furnished will not make itself felt immediately, but only after a certain stroke. There is then a delay in its action which should be repeated on the high pressure side in order that the high pressure admission may not be modified too soon, since this would result in an increase of power.

Care should be taken to see that the opening of valve 47 or of 49 will permit the delivery of the amount full load conditions when the turbine is suplied with low pressure steam only. Likewise when all the valves 3S to 41 and 42 to 45 are open, they should permit the delivery of the amount of steam necessary for full load conditions when the turbine is supplied with highpre'ssure steam only.

In accordance with theprovisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent th'e best embodiment thereof; but I desire to have it understood that the appainvention can be carried out by other means.

vVlhat I claim as by Letters Patent of the United States, is,

1. In combination, a turbine, sources o low and high pressure fluid supply therefor, a secondary obturator means for successively o ening and closing passages admitting high pressure fluid to the turbine, a secondary obturator means for regulating the supplyy of low pressure fluid to the turbine, a speed governor that controls both of said secondary obturator means, primary obturator means that control the passages of low and high pressure` fluid to said secondary means, and' a device responsive to the pressure of the low ressure fluid for actuating the primary o turatormeans.

2. In combination, a turbine, sources of low and high pressure fluid supply /therefon a secondary obturator means for successively opening and closingpassages admitting high pressure fluid to the turbine, a secondary obturator means for regulatin the supply of low pressure fluid tothe tur ine, a spe governor that controls both of said secondary obturator means,V a primary obturator means for successively opening and closing the passages, admitting high pressure tlu illustrative, and that the f of steam necessary forA v ioo to said secondary lhigh pressure obturator means,v a primary obturator means for regulating the secondary low pressure obturatormeans,

and a device responsive to the pressure of pressure fluid for controlling bothofthe low the primary obturatormeans.l

, 3. Incombination, 'a turbine, sources" of low and high pressure Huid supply therefor, a secondary obturator for successively 'opening and Aclosing ports admitting high pressure Huid to the turbine, a seconda obturator for throttling thesupply of low turbine, a speedgov# ernor that'controls both of saidsecondary obturators, lprimary obturators that control the passage of low and high pressure fluid to the secondary obturators, and means for actuating the primary obturators.

.4. In combination;

the supply of low pressure fluid to -ing and closing said a turbine, sources of fluid-'supply therefor that dier as to pres sure, a chest containing passages, a valve means for opening and closing the passages suecessive1y,fa second valve means for openpassages successively, a second valve chest, a pair of throttle valves in the one of said valveI means in the first named ehest and also one ofthe throttle valves, and

a means for actuating. the other of said valve meansand one also of said throttle valves.

second chest, a means for actuating In witness whereof, I have hereunto set l my hand this 21st day of-June, 1911.

PAUL MORTIER. Witnesses:

" H. C. Coxrz,

WERNERV HmDEBRAND.