US1844082A - Elastic fluid turbine - Google Patents

Description

Feb. 9, 1932. J. B. WALBRIDGE.

ELASTIC FLUID TURBINE Filed Nov.,27, 192s 2 Sheets-Sheet 1 WITNESS INVENTOR J. B-Walbrid ge BY 0.41M

ATTORNEY Feb. 9, 1932.

J. B. WALBRIDGE ELASTIC FLUID TURBINE 2 Sheets-Sheet 2 Filed Nov. 27. 1928 INVENTO R J.B.Wa .lbrnde BY G.

ATTORNEY WITNESS Patented Feb. 9, 1932 n srars PATENT orrics JOHN B. WALBRIDGE, or nssrne'ron, PENNSYLVANIA, ASSIGNOR T WESTINGHOUSE ELncrnIc & MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA ELASTIC FLUID TURBINE Application filed. November 27, 1928; Serial No. 322,177.

My invention relates to an elastic fluid turbine, more particularly to the casing or stationary structure thereof, and it has for 1ts object to provide improved construction thereof.

Another object is to decrease the leakage of motive fluid through the joints of the easing to the atmosphere.

A still further object is to reduce the number and. size of the bolts required to secure the turbine casing parts together.

A further object is to provide an improved form of passage in the stationary structure for bypassing the first stage during overload.

Another object is to provide a construction of nozzle chamber suitable for very high pressures.

The above and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a longitudinal vertical section through a turbine constructed in accordance with the present invention;

Fig. 2 is a top plan view of one half of the turbine cylinder base, as seen along the line I1II of Fig. 1;

Fig. 3 is an end view of the turbine, being partly in elevation and partly in section as seen along the line IIII of Fig. 1; and,

Fig. 4 is a horizontal section along the line EX V of Figs. 1 and 3.

Referring to the drawings more in detail, I show my invention applied to a high pressure turbine of the combined impulse reaction type. The present turbine exhausts at a pressure substantially above atmospheric pressure, for example, 315 lbs. per square inch, and receives motive fluid through the inlet at a pressure of, for example, 1400 lbs. per square inch.

The turbine includes a rotor enclosed by a casing 11. The casing 11 is divided along the horizontal plane 16 at the axis of the turbine into two parts, an upper half or casing part 12 and a lower half or casing part 13. Each of these parts is formed from a single solid forging, or casting and is provided with an integral extension 14 near the high pressure end.

A nozzle chamber 15 is formed in each of the casing parts and extends along an arc concentric with the axis, having its ends disposed close to but somewhat spaced from the horizontal plane 16 along which the casing is divided. The nozzle chamber is formed by cutting metal out of'the forging or casting of which the casing part is formed, but the metal at the end of the chamber is not removed, thereby providing an integral closure for the ends, and providing an effective seal for preventing leakage from the nozzle chamber to the joint at the horizontal plane. A nozzle block 17 covers the groove constituting the nozzle chamber, and expands motive fluid received from the nozzle chamber and directs the same against the impulse blades 18 in the impulse chamber 19.

A passage 21 is drilled in the extension 14, through which motive fluid from a conduit 22 is supplied to the nozzle chamber 15. The supply of motive fluid may be regulated by a valve 23 interposed in the conduit 22 and controlled by a governor 24.

For very heavy loads or overloads, the

capacity of the nozzle block 17 is insufiicient,

and it is the practice to bypass the nozzle chamber or impulse stage for heavy'loads. For this purpose, I provide a passage 25 in the extensi0n 14 by drilling the same therein. The passage 25 consists of a horizontal portion 26 shown "more clearly in Fig. 4, and a vertical portion 27. The vertical portion 27 is slightly off-set from the horizontalportion 26 as shown in Fig. 4, and a horizontal passage 30 is drilled transversely through the extension 14 to provide communication therewith. v A valve 28 is provided inthe passage 30 at the entrance to the vertical portion 27 A valve seat bushing 29 for the valve 28 is screw-threaded into the casing part, and the valve 28 ispreferably actuated by a screwthreaded stem .31 having a hand wheel 32.

The upper, and lower parts 12 and 13 are provided with accurately machined surfaces 33 and 34, respectively, which are joined to form the joints at the horizontal plane 16 along which the casing is divided. These The outer portions of the j oints, therefore,

seal against only the pressure differencebe tween the pressure in the exhaust chamber and atmospheric. pressure. "Any leakage from the high pressure regions within the casing is conveyed to the exhaust chamber 39.

It will thus be seen that the leairage to the atmosphere is reduced, as the outer portions of the joints seal against only a relatively small pressure difference.

The grooves 38. have a further advantage in that they reduce the number and size of bolts required to hold the casing parts together. The latter must be of sufficient strength to resist the pressure within the turbine tending to separate the parts, assuming this pressure to be effective on the joint surfaces to which it mightleak. By providing the groove 38, the horizontal area to which the high pressure within the casing might leak is reduced, the joint area beyond the groove 38 being subjected tora relatively 2;; small pressure tending to separate the casing parts. Thus the total possible pressure tending to separate the parts 12 and 13 is reduced. I

From the above description, it will be seen J that I have provided an improved construction of a casing for a turbine using very high pressures, such as 1400 lbs. per square inch.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is-not so limited, but is susceptible of various changes and modifica- 1 tions 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 or as are specifically set-forth in the appended claims. WVhat I claimis:

1. An elastic fluid turbine characterized in that it exhausts at a pressure above atmosf pheric pressure and comprising a rotor and a casing, said casing being divided into a plurality of parts having oined surfaces and one of said surfaces having a groove extending longitudinally of and between the ineluding a casing and a rotor in the casing, said casing being subjected within to the pressure of motive fluid therein and being divided into a plurality of parts having joined surfaces, one of said surfaces having a groove extending longitudinally of and between the inner and outer margins of a joint formed by said surfaces and communicating with a part of the interior of the casing where the pressure is greater than atmospheric pressure but less than the-pressure Within the casing at the high pressure end, said groove extending along a part of the casing wherein the pressure is greater than the pressure in the groove.

'3. An elastic fluid turbine comprising a rotor and a casing, said casing being divided into a plurality of parts having joined surfaces and said surfaces belng formed to provide conduit means extending longitudinally of and between the inner and outer margins of a joint formed by said surfaces, and means for connecting said conduit means with a region of lower pressure than the pressure existing within that portion of the turbine along which said conduit means extends.

4. An elastic fluid turbine comprising a rotor and a casing, said casing being divided into a plurality of parts having joined surfaces, said surfaces being formed to provide conduit means extending between the inner and outer margins of a oint formed by said surfaces and longitudinally of said joint adjacent regions of the'interior of the casing of pressures substantially above atmosphericpressure, and said conduit means communicating with a regionof' a pressure greater than atmospheric pressure but less than the first-mentioned pressures.

In testimony whereof I have hereunto subscribed my name this th day of November, 1928.

' JOHN B. NALBRIDGE.

ner and outer margins'of a joint formed by said surfaces and communicating with the exhaust chamber of the turbine.

2. An elastic fluid turbine characterized in that it receives motive fluid at a pressure substantially above atmospheric pressure and in-

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