US764433A - Support for intermediate buckets. - Google Patents

Description

PATENTED JULY 5, 1904.

. A. R. DODGE.

SUPPORT FOR INTERMEDIATE B'UGKETS.

APPLIUA'TIOI FILED D30. 21, 1903.

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N0 MODEL.

`VVVLrwBssees; I l I UNITED STATES Patented July 5, 1904.

PATENT OEEICE.

AUSTIN R. DODGE, OF SCHENECIADY, NEWv YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEf YORK.

SUPPORT FOR INTERMEDIATE BUCKETS.

SPECIFICATION forming part of Letters Patent N0. 764,433, dated July 5, 1904.

Application ledDeoomlIcr Z1, 1903. Serial No. 185,963. (No model.)

To all tf1/tom it may concern:

Be it known that I, AUSTIN R. DODGE, residing at Schenectady, county ofScheneetady, State of New York, have invented certain new 5 and useful Improvements in Supports for Intermediate Buckets, of which the following is efficiency of a turbine depends to a large eX` tent on the amount of' these clearances they are made as small as possible. When the intermediate buckets are stationary, which is the common construction, they are usually carried by'a support that is movable longitudinally of the wheel-shaft and casing to per mit manual adjustment of the clearances. With this construction the intermediates are fixed when .the turbineis in operation and it is only possible to adjust them by releasing j two or more bolts. Moreover, this operation i is a delicate one at best and requires a skilled operator. In other constructions the intermediates are lixed with respect to the easing and adjustment of the clearances can only be 3o had by moving the wheel-shaft longitudinally. These arrangements are satisfactory where relatively large clearances are employed and for small machines having short shafts, but are unsatisfactory where small clearances are 3 5 employed in multistage turbines or for those having' long massive shafts, for the following reason:

Suppose the turbine to be of the multistage type with a comparatively long steel shaft of 40 large cross-section. Thecasing is made of relatively thin cast-iron, and owing to the large surface presented to the steam expands morerapidly than the shaft. On the other hand, the shaft while surrounded by hot steam or other vapor has a large cross-section and is heated slowly, and therefore eX- pands more slowly thanthe casing. It is to be observed in connection with this matter that the expansion of the casing In the sevdation in a vertical machine or one end head in a horizontal machine. ,ln other words, while the expansion of the shell ma single stage may `be small the total expansion of all of the shells 5 5 is considerable. This means that the intermediate buckets vvill no longer occupy their proper relative position with respect to the wheel-buckets. If the clearances are small, the intermediate buckets will soon close them and engage with the wheel-buckets, and since the unequal expansion of the parts continues for a considerable length of time some of the buckets will be destroyed or badly damaged, and in practice it sometimes becomes necessary to shut down. Obviously shutting down a turbine after it has once taken its load is about the last thing' that the station man wants to do. The intermediates beingI usually fewer in number suffer the most. In some instances, where large clearances are employed, the parts will assume their normal relation after the shaft has had a chance to become thoroughly heated and expanded.

To state the` Inatter broadly, if `the wheel and intermediate buckets are relatively nonadjustable the clearances in order to compensate for the unequal expansion of the casing and shaft have to be equal or substantially equal to the amount of expansion of the cas- 8 ing plus that of the shaft. i

In addition to the above there are times when the wheelwarps slightly, which isprobably due to unequal temjjicratures of the wheel body and rim. It also happens that under 8 5 certain conditions a seesaw action takes placethat is to say, the casing and shaft will alternately expand and contract abnormally, duc to changes in the steamdelivered thereto and to the effect of tlie'comlenseI. 90

From the foregoing it follows that two general plans are followed, one being the use of large clearances, the other being the manual adjustment of the intermediates, or what, in effect, is the same, the manual adjustment of the wheel-buckets.

The object of my present invention is to provide a means for supporting intermediate buckets which is free from the objections above pointed out and which will permit of the use of minimum clearances either when the partsarecold or hot or one part is relatively hot as compared to the other.

In carrying out my invention instead of mounting the intermediate buckets iixedly on the casing or on their support, as is usual, they are so attached that they can under certain abnormal conditions move freely in one direction or the other, depending on the position of the wheel-buckets. In other words, the intermediate buckets float, and when a row or rows of wheel-buckets engage therewith, due to unequal expansion of the parts or otherwise, they are forced to the right or left in a horizontal machine, as the case may be, and up or down in a vertical machine. |The intermediates may be arranged segmentally or they may extend entirely around the wheel, as desired, and the invention is applicable to turbines in general without regard to the character of the buckets. Formed on' the casing or other suitable support are finished surfaces with which the intermediates or their framework engage. Suitable attaching means, such as bolts, hold the buckets normally in place, and interposed in and forming a part of each of the attaching means is a yielding medium, generally a metal spring. The use of large bearing-surfaces between the parts interposes sufcient resistance to prevent them from overtraveling and also acts, in effect, the same as a dash-pot. The relation of the parts is such that when some portion of the wheel rubs on the intermediate-bucket support it will force the buckets out of engagement therewith, the moisture which is in the wheel-casing acting as a lubricant to prevent damage. In this connection it is to be understood that the parts only touch momentarily, the movement of the wheel moving the intermediates into a new position. A number of rows of intermediate buckets can be attached to the same support, or each row or segment of a row can have its own support. The attaching bolts and springs are so positioned that they may be readily inspected by removing small coverplates from the casing. In order to insure proper alinement of the parts, it is best to provide each of the sets of intermediates with several retaining-bolts and generous bearingsurfaces between the relatively movable parts.

In the accompanying drawings, which illustrate one embodiment of my invention, Figure 1 is a partial horizontal section of a vertical turbine, and Fig. 2 is a partial vertical section of the same.

1 represents the wheel-casing, which is divided into as many sections as are desired, and the several sections are united in any suitable manner. vSome or all of the casing'- sections are provided with supports 3 for the intermediate buckets. By intermediate buckets is meant those buckets which receive iiuid from one row of wheel-buckets and after reversing its direction deliver it to the adjacent row of wheel-buckets. These supports present a finished surface on the side adjacent to the wheel, which surface is concentric with the axis of the wheel-shaft. Mounted on each of the' supports are intermediate buckets 11 of any suitable construction. These buckets may be arranged segmentally, or they may extend entirely around the wheel. When arranged segmentally, stops may be provided at the ends to prevent rotarymovement. The arc covered by said intermediates will be determined largely by the power of the machine and also by the volume of motive fluid to be handled. The supports 3 are perforated at two or more points, and extending through each perforation or opening is a retaining-bolt 5, that is screwed into one of the intermediate buckets or into its support. Surrounding the bolt is a collar 6, containing two or more anf tifriction-rollers 7, which engage with the back side of the support 3 and reduce the friction at this point. Situated between the head of the bolt and the collar 6 is a yielding medium in the form of a coiled compressionspring 8, which tends at all times to hold the intermediate buckets against their support. Situated in line with the retaining-bolts are openings 9, through which the bolts can be adjusted. v These openings are covered by small detachable plugs 10.

The intermediate buckets are situated between rows of wheel-buckets 11, which are formed in any suitable manner. Each row of wheel-buckets is provided with a cover 12, which is slightly wider than the bucket itself in order to protect the sharpened edges of the buckets from injury. The bucket-wheel is provided with a rim or enlarged portion 13, that also serves to protect the sharpened edges of the wheel-buckets from injury. Opposite the rim or enlargement 13 the intermediatebucket support is provided with a thickened or enlarged portion 14g. Vhen the wheel changes its position more than a certain amount, due to any cause, the parts 13 and 14 engage and cause the intermediate buckets to be moved up or down, as the case may be. I iind it preferable to support each row of intermediate buckets on a separate support rather than to mount them on a single support, because each row of buckets will then be independently adjustable and the inertia of the parts when struck by the wheel will be less.

Situated above the bucket-wheel and in line therewith is a nozzle or equivalent device 15, which discharges motive fluid against the wheel-buckets and causes rotation thereof. Under certain conditions I may omit the springs and collars and depend on the friction between the bolts and bucket-support to hold the intermediates in place.

In accordance with the provisions of the patent statutes I have described the principle IOO IIO

IIS

of operation of my invention,'together with the apparatus which I now consider to represent the best embodiment thereof; but I de sire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. An elastic-fluid turbine comprising sets of relatively7 movable buckets and a yielding support for one of said sets;

2. An elastic fluid turbine comprising' wheel-buckets and yieldingly-supported intermediate buckets.

3. An elastic fluid turbine comprising wheel-buckets and intermediates which are movable in an axial direction when engaged by the wheel.

1I. An elastic-Huid turbine comprising wheel and intermediate buckets, in combination with springs for supporting the intermediate buckets.

5. An elastic-Huid turbine comprising wheel and intermediate buckets, in combination with supports for the intermediate buckets, and yielding means for holding the buckets against the support.

6. An elastic-Huid turbine comprising wheel.

and sets of intermediate buckets, in combination with spring-supports for each set of. intermediate buckets. Y

7. An elastic-fluid turbine comprising wheel and adjustable intermediate buckets, in combination with a support for the intermediate buckets, means for holdingthe buckets in place, and antifriction devices to reduce the friction between said buck'ets and theirsupport.

8. An elastic-fluid turbine comprising a cas- 10. An elastic-Huid turbine comprising setsl of relatively movable buckets and their sup ports, in combination with projections on each of the supports to protect the sharpened edges of the buckets, and a yielding means for attaching one set of buckets to its support.

In witness whereof I have hereunto set my hand this 18th day of December, 1903.

AUSTIN R. DODGE. Witnesses:

BENJAMIN B. HULL, HELEN ORFoRD.

mg, and wheel and intermediate buckets, in `combination wlth a support carried bythe

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