US1131645A

US1131645A - Exhaust for steam-turbines.

Info

Publication number: US1131645A
Application number: US81732514A
Authority: US
Inventors: Charles Volney Kerr
Original assignee: Individual
Current assignee: Individual
Priority date: 1914-02-07
Filing date: 1914-02-07
Publication date: 1915-03-09
Anticipated expiration: 1932-03-09

Description

G. V. KERR. EXHAU ST FOR STEAM TURBINBS.

APPLICATION FILED FEB. 7,1914

Patented Maw, 1915;

mansions GHABLES V0141? EY KERR, 3F ELLS? Lil 1E, "1 03K.

FOR. STEAM-TUHBINES.

Specification. of Letters Patent.-

l atented Mar, 9., til

Application filed February 7,. 191 Serial no.

back pressure of the. turbine. Secondz'to so arrange and construct the exhaust pasa turbiuc,.that the residual velocity remaining in the exhaust steam after leaving the last bucket or vane can be utilized to increase the exhaustpressure, instead of Wasting it in needless and obstructing eddies, and therehy e'fiect a lower pressure the exhaust end of the turbine casing than in the connected exhaust pipe or chamber, heretofore used. Third: to so construct and arrange theexhaust passage of the turbine, that the residual velocity'remaining in the exhaust steam is utilized uniformly around and at all the buckets of the last bucket Wheel or rotor, therehy'providing a uniform pressure and discharge of fluid pressure at the periphery of the last bucket Wheel, at the dill'erent stages of expansion throughoutthc turbine. Fourth: other objects and advantages of the invention Will appear "from the dtailed description which will he hereinafter more fully given.

The invention consists of structural features relative arrangements ofthe elements of the inveution, which-will be hereinafter more fully? described and. particularly pointed out in the appended claims.

In the drawings, in Which similar reference characters indicate the same parts in the several fi ures of drawing; Figure 1 is a longitudinal scctionon'line lll of'Fig. 22, of the exhaust end of a turbine with the improved volute exhaust passage attached thereto; and Fig. 2 is a transverse section on line l1-ll of Fig. 1.

Referring to Fig. 1 of the drawingspln which the et'rhaust' end of a turbine is rep resented, 1 is a rotary shaft to which is sccured'in any suitable manner two rotary Wheels 2, 3,-having buckets 2, and 3",

' volute shapedenh A cap carry respectively, on their peripheries. 4 is a section of the rhino casing provided with the stationary nozzles for guiding the steam into the buckets 2, and is a ring having stationary reversing nozzles 7, to r eteive the steam. from the bucletets 2 on the rotary wheel end guide the sameinto thebuclrets 3 on the rotary Wheel 3. Said sections or rings s, and 6, are preferably independent of each other and are dovetailed at their oints,

and fornrno essential part of the present 1 invention, as anypther form or type or thr bine may be used ,;b'ut"'are illustrated in the present instance for the purpose ofsho'wing the constructlon and ndication of the i331:

1 proved exhaust passages with .a turbine.

'lhe exhaust end of "theflstesan' turbine is .ciosed by a need .8,-prov1ded with theiin proved exha'r passage preferably therein, sai austpassagc being provided With an exha nozzle 9 having its smaller annular opening the inner side of the head 8 adjacent to and in communication with the final exhaust irorh the turbine buckets, or exhaust ends of the series of s on the last rotary Wheel or hucke', rotor 3, as shown in l. annular exhaust nozzle 9 esp-ands outwardly and opens into an. exhaust passage 10, of, in creasing cross-sectional area and or" volute shape, said passage 10 having an outlet or discharge 11 which is connected to the usual exhaust pipe leadim to the atmosphere or The bottom of the passage 1G is prolghavinga valve,

condenser, o. sire-3. volute shaped exhaust ""lCl Ql with o not shown, to drainauy Water of condensa-' tron, or oil, which may collect. at this point. The head. 8 is proviced with an opening centrally disposed with respect to the rust passa e 10 and annular nozzle fo the passage of the shaft 1,. 111g he usual stufiing box 15 with packing glands, and a'hearing 16,.as shown, is firmly secured over the opening 13, and needs no further disclosure, as it forms no essential feature of the present invention.

The operation ofthe invention is as follows: The steam havingheen admitted into the inlet of the turbine, it passes through' o e or more stages, andlinally reaches the last stage, and then passes with a residual velocity from the exlihustvside of the last scriesfoi buckets or vanes 3 3, on the wheel LLO v against the .Walls of the volute exhaust passage 10, to form interfering eddies 1r needless friction against the walls of the exhaust passage.

The residual velocity in the annular nozzle 9, and the whirling action within the volute exhaust passage 10 results in a decrease of velocity and an increase of density in the steam issuing from the buckets 3', 3, and an increase in pressure of the exhaust steam.

'This means, for example, if the turbine eX- hausts against atmospheric pressure, the steam may expand in the turbine until the pressure in the last stage is somewhat less than atmospheric pressure. Or, if the exhaust is into a 'acuum, the pressure in the last stage may be as low as in the condenser, since the decrease in velocity of exhaust may balance the pressureacquired to overcome friction in piping between the turbine and condenser.

hat i claim is 1. A steam turbine comprising a cylinder, a rotatable shaft, bucket .wheels rotating with said shaft, a volutc exhaust passage having an'outlet and an annular inlet and of gradually increasing cross-sectional area from its inlet to its outlet, and an annular unobstructed nozzle having sections in planes passing through the axis of the shaft in the form of a diverging nozzle, the inlet of said annular nozzle being placed'at the discharge side of the buckets on the Wheel adjacent to the exhaust and the curvature of the outlet of the annular nozzle merging smoothly into the curvature of the annular inlet of the volute exhaustpassage.

' 2. A steam turbine comprising a cylinder, a rotatable shaft, bucket wheels rotating with said shaft, a volute exhaust passage having an outlet and an annular inlet, and Y an annular nozzle having sections in planes passingthrough the axis of the shaft in the form of a diverging nozzle, the inlet of said annular nozzle being placed at the discharge side of the buckets on the wheel adjacent to the exhaust and the outlet of the annular nozzle merging smoothly in the annular inlet of the exhaust passage, and said exhaust passage rranged so that exhaust steam from said buckets of said Wheel flows around the exhaust passage and issues from said outlet in a direction backward to the direction of rotation of the said bucket wheel.

In testimony whereof I aifix my signature in presence of two Witnesses.

GHARLESC VOLNEY KERR. Witnesses (J. \V. GREENFIEL M. E. RISING.