US1670069A

US1670069A - Bleeder turbine

Info

Publication number: US1670069A
Application number: US47509A
Authority: US
Inventors: Helander Linn
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1925-08-01
Filing date: 1925-08-01
Publication date: 1928-05-15
Anticipated expiration: 1945-05-15

Description

y bleeder turbine Patented May l5, 1928.v

LINN HRLANDRR, or NoRwoon,r .PENNSYLVANIA ,AssIeNoR' 'ro wnsfriNeHoUsn ELECTRIC a MANUFACTURiNe Contra-Air,V A CORPORATION or raamsYitvANIA.

BILEEDER TURBINE.

Application led August 1, 1925.

tion, whereby the structure of both is reduced to a minimum and either or both may be utilized to develop `power at the highest elliciency.

In the accompanying drawing forming a part of this specification, Fig. 1 is aview in elevation showing an elastic fluid turbine made in accordance with my invention; and Fig. Q is a diagrammatic view illustrating the operation of my improved apparatus.

Heretofore in the construction of bleeder turbines, as known to me, the'turbine has comprised two or more sections wherein the motive fluid is at different pressures, a bleeder connection between two of the sections and leading to some point where it is desired to employ the extracted steam for heating or process purposes, and an exhaust for the completely expanded steam passing through the low pressure section of the turbine, usually connected to a condenser. In such turbines, there is also usually some dividing means between the sections behind the bleeder connection, and interstage valves are provided controlling the dividing means, the object of which yis to vary-the supply of motive fluid to the bleeder connection. typical design of such apparatus is illustrated in the patent to Francis Hodgkinson, No. 1,071,420, issued Aug. Q6, 1913 'and assigned to the Westinghouse Electric and Manufacturing Company. Another type of which has been proposed employs no dividing wall Abetween the sec-` tions `at the bleeder connection but employs a reducing valve in the bleeder line itself, designed to afford a constant pressure beond the valve.

With either of the aforementioned types of bleeder turbines, the means for provid ing a constant pressure in the bleeder line affects the efficiency of lthe organizationl as a whole. The dividing wall in the turbine with its reducing valve being placed beyon Serial No. 47,509.

a section of the turbine where the steam has already been partially expanded and employed in doing work, aects the efficiency of the higher pressure sections in a way simllar tol adam in a streaml below a water wheel. It backs up the steam above it, slows down its velocity and thus subtracts from the work doneV `in passing through the higher pressure sections. n In addition to this, if the demand forbled steam is variable, the attendant variation inthe pressure and temperature characteristics of the steam passing lfrom the high pressuresection to the low pressure section is undesirable.

Where a reducing valve is employed in the bleeder line, the steam pressure at the'bleeder opening must be maintained higher than the pressure beyond the. valve at all loads at which steam is to to be bled. Since the pressure in the'turbine at the bleeder opening is influenced bothlby the load on the turbine and the quantity Vof team bled, provision must usually be made for a considerable excess ofpressure ahead of the reducing valve to enable the valve to maintain a practically. constant pressure in the bleeder line under varying conditions of bleeding and loading. As is well known, reducing the pressure of steam in this manner without allowingthe steam to perform work entails a loss of usefulenergy. The loss is liable'to be particu* larly large at high loads and when bleeding large quantities of steam.

The sacrifice of eiciency kentailed in the design of such .apparatus has led, in'many instances, to the provision of separate relatively small .non-condensing units, the total exhaust of which is utilized'in the heat-ing or process purposes. This practice, however, is open to the objection that yit greatly increases the cost of the,- installation, necessitating as it does the provision of separate casings, rotors, bearings and governing ap,- paratus. It is further open to the objection that valuable space needed in a power plant l is taken up bythe extra apparatus.

1n accordance with my invention, come the before-mentioned ,di-Hiculties' byv providing a turbine which comprises a Acondensing section and a' non-condensing section ink one casing, said sections being disposed within non-'communicating compartments within the casing. I further provide means whereby the control valves of: the

d two sections may be operated by one governyas cob

n also admitted through a ing mechanism to give preference in steam supply either to the condensing or to the non-condensing portions, as desired. I

provide means whereby the non-condensing section of Jthe turbine may be run idly when lbled steam is not desired, Without any appreciable loss in efiiciency ofthe apparatus. o

Referring now to the drawing forr a better understanding or my invention, I show in Fig. 1 a turbine 10 made in accordance with my invention and comprising a condensing section 11 and a non-condensing section 12. Motive fiuid for the condensing section Vis conduit 13 and after expansion in the condensing section is exhausted into a condenser 14.

Motive tiuid for the non-condensing section 12 of the turbine is admitted through a conduit 16 .and after partial expansion in said section is vdischarged to an exhaust conduit 17 through which it may be conveyed to heating apparatus, such as a feed` water heater 18.

The admission of motive fluid to the condensing section 11 is controlled by an admission valve r19. This valve is .controlled byawell-lnown form'of governing mechanism at 21,A which actuates -the admission valvefbymeans of a fluid vpressure relay embodying a controlling or .pilot valve 22 and an operating cylinder 23. Extending upwardly from the operating cylinder 23, as shown in Fig. 17 a piston rod24 is connected to a lever 26 which is pivoted at 27 and connected vat 28 Yto the admission valve stem.

'Motive fluid for the non-condensing section 12-is controlled by an admission valve 29. located in the conduit 16. The governor 21 is also adapted to control the-admission of' motive fluid to the non-condensing section 12 by meansofapiston Vrod 31.extending downwardly from the operating cylinder 23, as shown in the drawing, and connected to an operating stemr 32 of thefvalzve 29. -Motive fluid admitted to the `non-condensing section 12 is further cont-rolled by an admission valve 33 arranged yin series with the admission valve 29 and controlled by a Awell-known form` of pressure-responsive device 34 which is adapted to be connected to the exhaust conduit 17 in a manner to be more fully described later.

Referring now more 4particularly Y'to Fig. 2, the turbine 10 embodies acasing 36and a rotor 37. Mounted upon therotor 37 `in the condensing section 11 is a high lpressure stage 38 which may be of the impulse type. Steam is admitted to the impulse stage 38 y means of a nozzle 39 controlled by the admission valve 19. Following the impulse stage'38 of the condensing section are a plurality of reaction stages 41-41. VThe non` condensing section 12 of the turbine preferably comprises an impulse stage 42\to which steam is admitted through a nozzle 43.V The moving blades of the impulse stage 42 are carried by the rotor 37 and may be mounted in any suitable manner known to the art. The casing 36 is divided into non-communieating compartments by means of an annular web 44 which surrounds the rotor 37 between the impulse stage 42 and impulse stage 38. In order Ato minimize leakage be-V tween the two sections, suitable packing elements 46 may be provided to cooperate 'between the rotor 37 and the web members 44. Thus it may be seen that in :operation either the condensing section or the non-condensing Vsection may be run yentirely independent of the other. f

Inasmuch as there may be times vwhen there is no demand for -bled-steam, it may be desirable Ato ventirely shut down the nonl condensing section 12. I therefore provide the admission conduit 16 with a yhand-operated valve 47, and in the exhaust conduit 17 I provide a hand-operated lvalve 48. At 49 I show a three-way valve which is adapted to connect the exhaust conduitl? to the pressure-responsive device 34 when the non-'condensing section l2 is in operation. When the non-condensing section 12 is shutdown and thecondensing section 11. is

in operation, the three-way `valve 49 is yafr- .9

ranged tto Aconnect the exhaust conduit 17, be` tween Ethe valve 48 and the turbine casing,l with the condens-er 14 so as vto ensure that the impulse wheel 42 will run vin a rarefied atmosphere -ofexhaust steam. At the same time, thervalve 49 is adapted to connect the pressure-responsive device 34 with la source of higher lkpressure so as to ensure the closing the. ,pressure-controlled admission valve 33. n y

The-three-way valve 49 .may be manually operated as by a handle 51. The passages within the valve 49 are shown diagrammatically` in Fig 2, wherein Ythe valve is indicated `in the position that it occupies when the non-condensing section 12 is in opera` tion. Connection 'throughv the `valve between the exhaust conduit 17 and the pressure-re',- sponsive device 34 is made. through a passage 52and condu its.54 and 56. A second passage 53 `1s embodied in the 4valve and 1n this position is shown `in communication with Athe motive iiuid supply conduit 13 through a conduit-58, but .inthe fposition of the valve shown, fthe high pressure motive Huid cannot pass through vthe valve. When the `valve handle 51 .is turned clockwise, as shownin-the drawing-until it points downwardly, the high pressure motive fluid is connected Vto the pressure-responsive device 34 through the Ypassage 52 and conduit 54 and the fpassage 53 is `adapted -to connect the exhaustconduit :17 with the-condenser A14through a-conduit 57.

YFrom the lforegoing description, the `operation of .apparatus made in accordance with my 'invention will be apparent. Mot-ive fluid admitted to the condensing section 11 in the turbine is controlled by th-e governor 21 and afterexpansion in said section passes to the condenser 14 in the same way as if Athis section comprised an independent turbine. lt wil'l be apparent, therefore, that this section of the turbine may be designed with its successive stages arranged for the most efficient conversion of the available energy in themotive fluid. At the same time the non-condensing section 12 may be in operation with motive y fluid admitted through the conduit 16 and controlled by the

valves

29 and 33. The valve 29 being under control of the governor 21, can not admit sufficient motive fluid to permit the turbine to overspeed. The admission valve 33 being controlled by the pressure-responsive device 34 in communication with the exhaust conduit 17, further Controls the non-condensing section 12 so that the exhaust pressure is vthat required for the heating or process purposes for which it is utilized. Upon an increase in pressure in the exhaust conduit 17 above the setting of the pressure-respon sive device 34, the valve 33 is moved in a c'losing direction. Upon a decrease in pressure within the exhaust conduit 17 below the setting of the pressure-i.'esponsive device 34, the valve 33 is moved in an opening direction, thus providing for an even pressure of bled steam for the purposes desired. In case no bled steam is required, the noncondensing section 12 may be entirely shut down by closing the valves 47 vand 48. The

tliree-way valve 49 is then turned so as tol connect the conduit 17 with the condenser 14, ensuring that the impulse wheel 42 will run in a rarefied atmosphere of exhaust steam, reducing its windage and permitting the condensing section 11 to operate only slightly hampered by the idly-running section 12.

Should therevbe an increase in load on the turbine and the governor 21 should act to increase the supply of motive fluid to both sections of the turbine and increase the pressure in the bleederline above that desired, the pressure-responsive device acts through the valve 33`to restrict the supply of motive fluid to the non-condensing section of the turbine. The governor 21 then acts to increase the supply of motive fluid to the condensing section to take care of the increased load. It will be apparent that with the

valves

19 and 29 under the control of one speed governor, they may be designed to give preference in steam supply to either the condensing lor non-condensing section of the turbine depending on whether there is to be a variable load demand or a variable demand for bled steam. Each of the power developing sections acting as a unit withturbine embodying a condensingsection andy a non-condensing section enclosed within a common casing andadapted to meet a `wide variation in power aiid-bleedervdemand or bot-h, lwhile operating at the highest efficiency.

l/Vhile I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without "departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed `thereupon as are imposed by the prior art 'oras are specifically set forth in the appended claims.

vWhat I claim is: L

1. The lcoiribinationf of a turbine vvcasing divided into compartments, a rotor with a shaft extending through the compartments, means for minimizing leakage of fluid from one compartment to the other, separate power developing sections arranged within the compartments, separate motive fluid inlets and exhaust outlets for the sections, a condenser connected to the exhaust of one of the sections, heat utilizing apparatus connected to the exhaust of another section, valve means for closing 0E communication gli between the heat utilizing apparatus and itsv associated section, and other valve means for closing the motive fluid inlet to-said section and opening communication between the exhaust outlet of said section and the condenser.y

2. A power developing unit comprising a turbine casing, a first and a secon-d power developing section arranged within the cas-v ing and employing a common shaft, meansV carried by the casingfor dividing the sections and minimizing leakage of motive fluid therebetween, a` condenser receiving the exhaust from the rfirst section, an exhaust conduit for the second section, separate niotive fluid inlets provided with admission valves for the sections, meansA responsive to pressure for controlling the admission valve of the 'second section, and valve means for closing the admission valve to the second section. and connecting the exhaust conduit with the condenser when desired.

3. A power developing unit comprising a turbine casing, a first and a second power developing section arranged within the casing and employing a common. shaft, ymeans carried by the casing for dividing thefsec' tions and minimizing leakage of motive fiuid therebetween, a condenser receiving the exhaust from the first section, an exhaust conduit for the second section, separate motive fluid inlet conduits for the sections, any

admission valve :in 4each of the conduits, vva speed-lfesponslve governor for controlling y the admission valves, sa second `admission va1vear1anged in series with the Agovernor controlled admission valve. for the second seetion, a pressure-responsive device toom!- municating with-the lexhaust eonduitfof the f second section Ifor'controlling Vthebseond advmission.va1ve, .v a'lve means adapted 45o -oon- 10 neet thepressure-responsive y,device With a gommone source fo-f relatively .high gpressure k-.fofr xclos ing'ithe motive `fiuidfinlet to the .second .section rand for opening feommuniozntion dine.

subscii'bed :my )name this twenty-fourth day of `July 1925.

HELANUEH