US3204931A

US3204931A - Stay ring for water turbines, pump turbines and pumps

Info

Publication number: US3204931A
Application number: US278708A
Authority: US
Inventors: Edvardsen Edgar Sigfred
Original assignee: Nydqvist and Holm AB
Current assignee: Nydqvist and Holm AB
Priority date: 1962-05-07
Filing date: 1963-05-07
Publication date: 1965-09-07
Anticipated expiration: 1982-09-07
Also published as: ES288324A1

Description

Sept. 7, 1965 E. s. EDVARDSEN STAY RING FOR WATER TURBINES, PUMP TURBINES AND PUMPS Filed May '7, 1963 FEED SP/RAL.

TURB/NE S/MFT FIG. 3

1N VENTOR E064)? S/GFFED EDWRDSEN BY H0413 ,4 TTORNEYS United States Patent STAY RING FOR WATER TURBINES, PUMP TURBINES AND PUNEPS Edgar Sigfred Edvardsen, Trollhattan, Sweden, assignor to Nydqvist & Holm Aktieholag, Trollhattan, Sweden, a corporation of Sweden Filed May 7, 1963, Ser. No. 278,708 Claims priority, application Sweden, May 7, 1962, 5,104/ 62 1 Claim. (Cl. 253-26) The present invention relates to stay wheels for water turbines, pump turbines and pumps, and particularly to the form of the stay rings comprised in the stay wheels in a welded design. The stay wheel, which consists of an upper and a lower stay ring and a number of intermediary stays, serves two purposes. For one thing, it comprises part of the water-ways, as it guides the water between the feed spiral and the guide wheel and, for another thing, it absorbs the forces between the feed spiral, the head cover and the bottom ring.

It has previously been the usual practice to make the stay rings of cast steel, but owing to the development of Welding methods and the general tendency towards larger units, welded designs have come more and more into the foreground. When stay rings were made of cast steel, thme were designed primarily with a view to obtaining an appropriate form, seen from a hydrodynamic point of View, and this had the consequence that they consist of double-bent elements. When changing to welded designs, the form used when the rings were made of cast steel has been retained, in general, which, however, involves certain disadvantages. The manufacture of the double-bent elements comprised in conventional stay rings involves certain difiiculties and is very expensive, particularly when it is a question of large plate thicknesses, and the force emanating from the feed spiral will be given considerable leverage in stay rings made according to this design. This great leverage causes a considerable rolling moment for the stay ring, which results in increased requirements for its dimensioning.

The above-mentioned disadvantages are avoided in the present invention, which relates to a stay ring of a welded design for water turbines, pump turbines and pumps, and is characterized, in general, in that said stay ring is constructed of a plane ring-formed plate, fitted at right angles to the shaft of the unit, and a conical sweep, which connects said ring-formed plane plate to the feed spiral. The conical sweep should appropriately be inclined at such an angle that the forces emanating from the feed spiral obtain the least possible torque lever and, further, the plate comprises a direct extension of the plate in the feed spiral. The conical sweep can possibly be supplemented with a thin covering plate, to obtain improved flow conditions and, finally, the stay ring can be made with stiiiening elements.

The invention will be described in more detail with reference to the designs shown in the attached drawing. In the drawing, FIGURE 1 shows in perspective, and with certain parts cut away, a stay wheel with stay rings made according to the present invention, and FIGURE 2, a section through the upper of these stay rings. FIGURE 3 shows a section of an upper stay ring according to a modified design of the present invention.

In FIGURES 1 and 2, 1 designates a plane, ring-formed plate, arranged at right angles to the shaft of the unit. A conical plate sweep 2 is welded to this plane, ring- Patented Sept. 7, 1965 formed plate 1. The conical sweep 2 is inclined at such an angle that the forces emanating from the feed spiral (not shown in the figure) are given the least possible torque lever. The seam between the two

parts

1 and 2 should be machined on the side directed downwards, so that a well rounded transition is obtained. The two

plate elements

1 and 2 are comparatively easy to manufacture, and together give a very stable stay ring even when the plates used have only moderate dimensions. This stay ring 12 is welded to the upper part of the stays 3, the lower ends of which are connect-ed to a stay ring 4-5 made in the same way.

Should the stay ring composed of the plane, ring-formed plate and the conical sweep not have a satisfactory form, seen from the point of view of flow, it can be supplemented with a thin covering plate 8, which guides the water in the way desired. As is shown in FIGURE 3, the plane, ring-formed plate 6 and the conical sweep 7 are rounded oli by the covering plate 8. The stay 9 is fastened to the plate elements 6 and 7, and the only purpose of the covering plate 8 is to guide the water. Thus, it can be made of comparatively thin plate, whereby it will be easy to manufacture.

Generally, the stay ring made of the plane, ring-formed plate and the conical sweep have entirely satisfactory mechanical stability, but if it should be desired to further improve this stability, this can be achieved by means of stiifening elements of a simple geometrical form. Thus, it is shown in FIGURE 3 how the stay ring 67-8 has been provided with a cylindrical stiiiener 10. In this case, the stay 9 protrudes through the conical sweep 7 and is firmly attached to the cylindrical stiffening ring 10.

I claim:

A stay ring structure for turbines and turbine pumps, said stay ring structure comprising an annular plate, a plane sweep ring fixedly secured along one edge to the outer periphery of said plate, said sweep ring including a slot and extending outwardly of said plate at an angle in reference to the plane thereof, said sweep ring including at least one stay and an annular stiffening member secured to said annular plate coaxially therewith and rising therefrom on the same side as said sweep ring, said stay extending through said slot and being secured to said stiffening member, and a flow-guide plate covering the outside of said sweep ring and secured thereto along its edges and extending to the outer periphery of said annular plate, said flow-guide plate being concavely curved in reference to said sweep ring.

References Cited by the Examiner UNITED STATES PATENTS 1,896,644 2/ 33 Pfau 253117 2,291,110 7/42 Sharp 253-122 2,524,390 10/50 Bach et al. 230133 2,736,530 2/56 Koepke 253-422 X 2,808,227 10/57 Danel 253117 3,051,441 8/62 Sproule 253-117 3,139,265 6/64 Lindquist 253117 FOREIGN PATENTS 876,230 5/53 Germany.

SAMUEL LEVINE, Primary Examiner.

JOSEPH H. BRANSON, JR., JULIUS E. WEST,

Examiners.