US1695751A - Radial flow turbine - Google Patents

Description

Dec. 18,1928. 1,695,751

0. A. WlBERG RADIAL FLOW TURBINE Filed Aug. 20, 1927 Patented Dec. 18, 1928.

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' RADIAL FLOW TURBINE.

7 Application filed August '20, 1927, Serial No. 214,322, and in Grea't Britain August 30, 1926.

This invent-ion relates to elastic fluid turbines, as steam or gas turbines, of the radial flow type having an axial flow systemto be driven by the driving mediumafter it has left the radial flow system.

The invention has for its object to provide an improved axialflow system for such turbines whereby thedriving medium may be utilized in the best way possible by the axial flow system. To this end the axialflow sys tem includes'a stationary guide blade wheel the passages of which are divided into a'plurality of sections so dimensioned that a section of a smaller diameter has a narrow inlet area and a wide outlet area as compared with the corresponding areas of a section of a greater diameter so that the velocities of the driving medium will be proportional tothe peripheralvelocities of the axial flow blading at different radial distances from the turbine Other features will appe'arfrom the following description withrreference to the accompanying drawing. w

In the drawing, Fig. l is an axial section of part of a turbine according to the inven tion. Fig. 2 shows a detail on a larger scale. Fig. 3 is an axial section of a somewhat modified form of the guide blade disc of the axial flow system. I

The turbine illustratedis of the type having blade wheels running in opposite diree tions. It is to be noted, however, that the invention is not. limited to said type of turbine. i 7

VVith reference to the drawing the numeral 1 indicates the radial flow system of'blade wheels. o

Outside said radial flow blade system there is provided an axial flow system represented in the drawing by a blade wheel Q'and a guide blade disc 3. .The blade wheel 2 is carried by a ring shaped member 4 of the turbine disc.

The guide blade disc comprises an outer ring 5 and an inner ring 6 connected together by the guide blades proper 3. The guide blades 3 with the said rings 5 and6 comprise a single piece made by casting. The outer ring 5 is securedto the casing 7 of the turbine and forms part thereof, while the in her guide blade ring 6 extends towards the supporting ring 8 of the outermost blade drum of the radial flow system, said supporting ring having, preferably, a packing edge 9 engaging the ring 6.

The guide blades 3 are provided with a dividing ring 10 to divide the driving me dium coming from the blade wheel system 1 into two st'reams'so as to cause positively part of said driving medium to enter the StXlELl ii ow system near the inner periphery thereof. Said dividing ring may either,. as shownin Fig. 1 have arathershort radial extension or may, as shown in Fig. 3, extend inwardly to the strengthening ring 13 of the outermost blade drumof the radial flow system. such, case, said strengthening ring 13 may be provided with a packing edge'l l to cO-operate with the ring 10.1

The areas-of the guide blade disc 3 to be passed by the driving medium are chosen so that the velocities of the driving medium will be in proportion to the peripheral velocities at different radial distances from the axis of the turbine. As a result, efficiency of the axial flow system willbe as high as possible, the stresses being at the same time uniformly distributed, and the formation of undesired currents of thedriving medium avoided.

In order to explain this result more.clearly it should be noted that the same pressure exstages, each stage corresponding to a certain steam velocity. v allowing a larger pressure drop in the port-ion of the drums to the right of the partition the velocity of the steam to the right at its exit from the guide blade 2 will be less than that of the steam to the leftof the partition 10. In this way it is possible to obtain a relation 'of the steam velocity at the blade root to that at the blade top substantially equal of the relation of the peripheralvelocities at those points and, as

a result, substantially uniform speed trian- In order to remove water from the steam,

when steam is used as driving medium, before it reaches the blades 2 there is provided at v the outer edge of the ring 5 a water collecting groove 11, Fig. 2, into which the water is led due to the action of the centrifugal force and whence the water may escape through apertures 12.

What I claim is:

1. In a radial flow elastic fluid turbine, the combination with an axial flow rotary blade system to be operated by the driving fluid after it has left the radial flow blade systennot a non-rotary guide-blade system divided into a plurality of concentric sections so dimensioned that a section of a smaller diameter has a greater proportional increase in eliective cross section than the section of a greater diameter so that the velocities of the driving medium at different diameters of the axial flow blade wheel will be proportional to the peripheral velocities at said diameters.

2'. In a radial. flow elastic fluid turbine, the combination with an axial flow rotary blade wheel to be operated by the driving fluid after it has left the radial flow blade system, of a non-rotary guide-blade disk divided. into a plurality of sections so dimensioned that a section of a smaller diameter has a greater proportional increase in effective cross section than the section of a greater diameter so that the velocities of the driving medium at different diameters of the axial flow blade wheel will be proportional to the peripheral velocities at said diameters, and means on said guide blade disk to distribute uniformly the driving fluid along the entire lengtl'l of blade of said disk.

, 3. In a radial flow elastic fluid turbine, the combination with the radial flow blade sys tem, of an axial flow rotary blade wheel to be driven by the fluid after it has left the radial system, a non-rotary guide-blade disk associated with said wheel}, divided into a plurality of concentric sections, and a ring to divide the driving fluid into an inner and an outer stream on its way from the radial flow system to the axial flow system.

4:. In a radial flow elastic fluid turbine, the

combination with the radial flow blade system, of a strengthening ring secured to the outermost blade drum of said system, an axial flow rotary blade wheel to be driven by the fluid after it has left the radial system, a non-rotary guide-blade disk associated with said wheel divided into a. plurality of concentric sections, and a ring secured to said disk and extending to said strengthening ring to divide the driving fluid into an inner and an outer stream on-its way from the radial flow system to the axial flow system.

5. In a. radial flow elastic fluid turbine the combination with the radial flow blade system, of a strengthening ring secured to the outermost blade drum of said system, anaxial flow rotary blade wheel to be driven by the fluid'ai'ter it has left the radial system, a nonrotary guide-blade disk associated with said Wheel divided into a plurality of-c'oncentrie sections, a ring secured to said disk and extending to said strengthening ring to divide the driving fluid into an inner and an outer stream on its'way from'the radial flow system to the axial flow system, and packing means between said strengthening ring and said driving ring. I

6. In a radial'fl'ow elastic fluid turbine, the combination with an axial flow rotary blade system to be operated by the driving fluid after it has left the radial flow blade system, of a non-rotary guide-blade system divided into a plurality of concentric sections so dimensioned that a section ofa smaller diameter has a greater proportionalincrease in effective cross section than the section of a greater diameter so that the velocities oi the driving-medium at different diameters of the axial flow blade wheel will be proportional to the peripheral velocities at said diameters, and draining? means provided at the outer edge of said guide blade system.

In testimony whereof I have signed my name. 7

OSCAR ANTON WVIBERG;

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