DE541846C - Blading for radially loaded turbines - Google Patents

Description

ISSUED ON JANUARY 22, 1932

REICH PATENT OFFICE

PATENT LETTERING

Jift 541,846 CLASS 14 c GROUP

Aktiebolaget Ljungström's Angturbin in Stockholm *) Blading for radially admitted turbines Patented in the German Reich on February 6, 1929

The invention relates to blading for radially loaded turbines. With these has So far, turbines of lower power, namely up to about 750 kW, are built in such a way that the Steam flow is single-flow. The size of these turbines can be determined as follows: that the outlet cross-section at the outermost radially acted upon blade ring this

Turbines is smaller than the value 0.4 I- 1,

where η is the speed of the turbine.

In the case of radially loaded turbines of greater power and an outlet cross-section that exceeds the aforementioned value, the outer blading was consistently designed with multiple flows, the steam flow being subdivided into a series of up to six steam flows. With this type of construction, the aim was to keep the diameter of the turbine as small as possible, but it was necessary to achieve great blade lengths, which could only be managed with a multi-flow construction.
This development of the radially loaded high-performance turbines has led to unfavorable designs in that the multi-flow turbine has an extraordinarily high number of blades and, moreover, has caused friction, eddy and flow losses within the blade system.

These deficiencies of the previous development are eliminated by the present invention, which consists, in the case of radially admitted turbines, their outlet cross-section at the outermost radially loaded blade

ring is greater than 0.4 · I j, the blades up to the outermost radial blade ring to be single-flow and the blades of the last blade rings in terms of width and increasing the length progressively faster than the length and width of the inner blade rings.

The invention achieves, on the one hand, good steam guidance and good relaxation conditions, on the other hand, however, a considerable reduction in the number of blades of the turbine and an improvement in its efficiency.

In comparison with a double-circulating turbine of the previous one calculated for the same output Design with axially loaded low-pressure blading is achieved by the invention, that the number of blades of the turbine is reduced to about a third, this Significant simplification gained by no means at the expense of the efficiency of the turbine he follows; on the contrary, this is increased. The use of wide blades is beneficial for efficiency in that the wide blades have less friction than the narrow shovels. The invention can also be used in such turbines, especially for find great services "use", which apart from the radially acted blading

*. ' The patent seeker stated as the inventor:

AIf Lysholm in Stockholm.

Claims (1)

also have axially loaded blades. An embodiment of the invention is shown in the drawing.
S it shows Fig. Ι an axial section through a turbine according to the invention, Fig. 2 a modification of the embodiment according to Fig. I, ίο Fig. 3 a section along the line AA in Fig. 2, Fig. 4 is a top view of the embodiment according to Fig. 3, Fig. 5 is a speed diagram. In Fig. Ι 1 is the center line of the turbine shaft, while 2 and 3 denote two turbine shafts rotating in opposite directions. The steam reaches the turbine through channel 4 in the direction of arrow 5 and ao flows with the release of energy from the central space 6 through the first blade ring 7 and then through all the Schaufehinge in the radial direction to the outlet 8, the bounded to the outside by the turbine housing 9 as will. The blades 10 of the outermost blade ring are considerably wider in the radial direction than the inner blade rings. The width, i.e. H. the radial extension of the blades is in accordance with the permissible building material stress to choose. In the embodiment according to Fig. 2, the steam flows through the blades from the The blades 7 after the blade part 10. The blades 10 here have a radial extension δ, which is significantly larger than the width of the ring bandage in which it is attached are. The steam can thus, after it has passed the ring bandage 18, to the room or outlet 8 escape through a channel in the axial direction, as indicated by the arrow 19 is indicated. In this case too, the blades 10 are wider than the blades 13 of the adjacent inner blade ring, and these blades 13 are in turn wider than the shovel 14 located within it. All of the blades 10, 13 and 14 are substantial wider than the blade shell which is closer to the turbine shaft, for example the blade shell 12. The outermost blade ring also fulfills the requirements of Fig. 1 with regard to the outlet cross-section condition described; around the large outlet cross-section required for this Maintaining blade rings with little expansion in the axial direction is to be obtained A possibility has been provided for the exhaust steam from the last Schaufehing in to escape in the axial direction, as already described above and shown in Fig. 3. In Fig. 4 the ring bandage 18 is again illustrated, who carries two Schaufehl 10. At that point near the concave surface of the blades where the steam preferably also flows in the axial direction, e.g. according to Fig. 2, small, radially positioned blades 20 are provided, which for deflection of the steam in the desired direction. This also has the advantage of that the radial inlet velocity after the extreme in the radial direction Blade ring is greater than the radial outlet velocity from the same blade ring. This relationship is illustrated schematically in Fig. 5, which shows the display of the outermost blade ring and the blade ring adjacent to the outermost ring shows. The two blade rings are in reality so that only a small gap is present between them, these vane rings in opposite directions circulate. C ₁ and C ₂ in Figure 6 are the respective relative outlet velocities of the steam in relation to the blade. U ₁ and U ₂ are the respective peripheral speeds of the blade rings in relation to the next following blade ring or steam outlet, W ₁ and w _s are relative inlet speeds to the next blade or to the steam outlet. W ₁ is directed approximately radially, and its projection on the radius is denoted by W _1. The projection of W ₂ on the radius is denoted by W _3. W ₁ should be greater than W ₂ . With ■ blades according to the present invention can without using a special axially loaded blading, larger turbines can be built cheaper than this was previously possible. This limit is from 3000 kW normal load to 10,000 kW normal load or from 4200 kW maximum constant load to 14,000 kW maximum constant load Load increased. TANSFRU CU: Blading for radially loaded turbines, the outlet cross-section of which at the outermost radially loaded blade ring is greater than 0.4 ( ³ ° ⁰⁰ 1, characterized in that that the blading is designed to be single-flow up to the outermost blade ring and the blades of the last blade rings grow progressively faster in terms of width and length than the blade length of the inner blade rings. ^{1 1} ^ For this purpose 2 sheets of drawings