US2837309A - Turbine - Google Patents

Description

Jun 3, 1958 A. IF. HANSCHKE 2,8 7, 09

TURBINE Filed Dec. 19, 1955 2 Sheets-Sheet 1 INLET 2 EXHAUST s 9 H 4.- I9 I 4 I7 2 3 l9 I ,9 I 5 5 I l I muwuuu ALBERT F. HANSCHKE syi lw June 3, 1958 A. F. HANSCHKE TURBINE 2 Sheets-Sheet 2 I Filed Dec. 19, 1955 FIG. 6

ALBERT F HAmsg lgm-t BYIQM'J 0- TURBINE Albert F. Hanschke, Wellsville, N. Y., assignor to Worthington Corporation, Harrison, N. J., a corporation of Delaware Application December 19, 1955, Serial No. 553,932

3 Claims. (Cl. 253-71) 7 Turbines are known where the steam goes several times through the same bucket row. In these turbines either the steam has to be turned around 180 and flows then through the same buckets in opposite direction or the steam is turned around 360, goes through another noz- United States Patent D zle group and then again through the same bucket now in the same direction as the first time.

The first kind of turbines are usually built like a 2 or 3 row Curtiss wheel, where almost the total drop is converted into velocity in the first nozzle. The steam therefore leaves the bucket row the first time with a very high Velocity and the losses by turning the steam 180 back are very high. Moreover, the buckets cannot be designed for the best efiiciency in the second pan but have to be used as they are and in opposite direction as the first time. The efiiciency of these turbines is not very high and lower than in a usual 2 or 3 row Curtiss wheel. They can be used only for partial admission and therefore, in general, only as a first stage of a multistage turbine or as a single stage turbine.

In the other kind of turbines, where the steam is turned around 360 a second group of nozzles can be used to convert additional drop into velocity, so increasing the efliciency of the turbine. But also here the same buckets have to be used as for the first stage. The turning losses are kept low by using special ditlusor nozzles after the buckets, in order to turn the steam around with a low velocity. But besides the normal leakage losses between the stages through labyrinth packings, there are here additional leakage losses between the nozzle groups of the different stages, where a reduction by using labyrinth points is not feasible. Moreover, the whole design of these turbines, especially the casing, is complicated. These turbines also are confined to stages with partial admission. All these confinements are avoided by the present invention. Also the efficiency is improved and the casing is not more complicated than a normal turbine casing. The idea is to use the wheel of a turbine stage as a support for one or more other rows of buckets, which are inserted within the wheel between the outer row of buckets at the rim and the hub. In this way the buckets can be selected with the best height and the best angles for the nozzles of each stage regardless of the bucket angles and heights of the preceding stages. There are completely new stages consisting of separate nozzles and corresponding buckets.

The present invention can be applied not only to a single stage turbine with partial admission but also with higher efliciency to a stage with fully admission and to multi-stage turbines.

In prior practice, normally a turbine with an overhanging wheel consists of only one stage because 'it is important to keep the deflection of the shaft down and the critical speed of the rotor high. Such operation is substantially impossible with more than two wheels. The range for a turbine with high efficiency is only one which is therefore limited to that adiabatic heat drop of steam "or gas which can be converted with high efiiciency in a single stage. 1

The present invention however provides an overhung wheel turbine whose range can be more than doubled in that the present invention embodies a structure of overhanging wheel embodying two or more complete and separate stages which can convert more than twice the adiabatic drop with the best efliciency and a turbine, the weight and dimensions of which are about the same as those of a conventional turbine with only one stage.

-With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a turbine of a preferred form embodying the invention and the features forming the invention will be specifically pointed out in the claims.

In the drawings.

Figure l is a side elevation of a turbine made in accordance with the present invention.

Figure 2 is a fragmentary longitudinal section through the turbine.

Figure 3 is a detail cross section on the line 3-3 of Figure 2.

Figure 4 is a detail horizontal section taken on the line 4-4 of Figure 2.

Figure 5 is a detail horizontal section taken on the line 55 of Figure 2.

Figure 6 is a perspective view of the turbine wheel having parts broken away.

Referring particularly to the drawings, the turbine of the present invention consists of the usual casing or housing 1 having an inlet 2 and outlet 3 for the motive fluid such as steam or gas. The wheel 4, which is an overhanging wheel is supported in a bearing 5.

General control valves (not shown) of approved construction are employed to govern the motive fluid, such as steam or gas, for different nozzle groups according to the dilferent load points as is usual in turbine construction.

The steam or gas coming from one control valve (not shown) through the inlet 2 enters the ring chamber 6 of the corresponding nozzle group 7. The steam expands in these nozzles 7 and flows through the buckets 8 in the usual manner.

The buckets 8 are mounted on the overhanging wheel 4. The first stage, therefore acts as a control stage as is usual for a multi-stage turbine.

The second stage of the turbine consisting of the nozzles 9 and the buckets 10 may also be considered as a normal stage. This second stage consisting of the'nozzles 9 and buckets 10 has full admission of steam or gas all around from the first stage consisting of the buckets 8 and nozzles 7 through the space 11.

After this second stage, two additional stages are added by novel and newfeatures of construction.

From the buckets 10 the steam or gas flows to the nozzles 12 and buckets 13. In the present invention, as clearly shown in Figure 2 of the drawings the nozzles 12 are mounted axially while the buckets 13 are mounted radially, thus the flow of steam is in a substantial radial path through the nozzles 12 and a substantial axial path through the buckets 13. These nozzles Patented June 3, 1958' 3 12 are mounted on a diaphragm 20, while the buckets 10 and 13 are mounted for rotation with the wheel 4.

The steam or gas passes from the stage consisting of the nozzles 12 and buckets 13 to a succeeding stage consisting of the nozzles 14 and buckets 15, the buckets 15 being carried by the Wheel 4 and are disposed axially and radially respectively on the wheel in the same man ner as the nozzles 12 and buckets 13. The steam or gas leaves the buckets 15 and passes out through the exhaust 3.

As will be seen by particular reference to Figures 2 and 6 of the drawings the second Wheel or the section 16 of the wheel 4 consists of two rings 17 and 18 connected by the buckets 13 and '15 and havingthe buckets 10 about its periphery, the labyrinth packings 19 being provided on both sides of the said rings to reduce interstage leakage. The nozzles 12 are supported in a diaphragm 20 which is carried by the casing 1 as clearly shown in Figure 2 of the drawings.

The nozzles 14 of the fourth stage are supported by the diaphragm 21 which also supports the nozzles 9 of the. second stage. Thus all four bucket stages of the turbine are carried by a single overhung, wheel, with the buckets of the second, third and fourth stages disposed in a plane radial to the wheel and the first stage buckets disposed'laterally of but in substantial axial alignment with the buckets of the second stage.

The turbine just described may serve as' a complete turbine but may also serve as the front end of a following low pressure turbine of any suitable construction.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be modified within the invention defined by the claims.

What is claimed is:

, 1. In a multistage turbine including, a single overhung wheel, buckets forming at least four separate turbine stages carried by said wheel, the buckets of the second, third and fourth stages being disposed in a common radial plane substantially perpendicular to the axis of rotation of the wheel, and the buckets of the first stage being disposed laterally of the buckets of the second stage.

2. A multi-stage turbine as claimed in claim 1 which includes a casing, said casing having an annular space therein between the buckets of the first and second stages respectively whereby said second stage buckets will have complete all around motive fluid entrance.

3. A multi-stage turbine as claimed in claim 1, including a plurality of sets of nozzles, one set for each set of stage buckets, the axis in the direction of driving fluid of the nozzles of the third and fourth stages being disposed substantially at right angles to the axis in the direction of driving fluid of the nozzles of the first and second stages.

References (Iited in the file of this patent UNITED STATES PATENTS 784,989 Drake Mar. 14, 1905 793,583 Hewlett June 27, 1905 1,238,457 Thomson Aug. 28, 1917 2,007,408 Schellens July 9, 1935 FOREIGN PATENTS 66,862 Netherlands Dec. 15, 1950

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