US3820570A - Suction bend conduit for use with centrifugal pumps - Google Patents

Abstract

A tubular curved conduit body is provided with an inlet and an outlet, the latter to be connected with the intake of a centrifugal pump. One or more guide vanes extend across the passage of the conduit intermediate the inlet and outlet and are each composed of two sections fast with the conduit body at diametrally opposite locations and having inner ends which extend toward but are spaced from one another.

Description

United States Patent [191 Holzhuter June 28, 197

[ 1 SUCTION BEND CONDUIT FOR USE WITH CENTRIFUGAL PUMPS [75] Inventor: Erich Holzhuter,

Lutzelsachsen/Weinheim, Germany [73] Assignee: Klein, Schanzlin, Becker Aktiengesellschaft, Frankenthal (Pfalz), Germany 221 Filed: July 13, 1972 21 Appl.No.:272,91l

[30] Foreign Application Priority Data July 14, 1971 Germany 2135097 [52] US. Cl 138/39, 415/183, 415/216, 415/208 [51] Int. Cl..- Fl5d U114 [58] Field of Search 415/183, 185, 184, 208, 415/209, 219; 138/37, 39

[56] References Cited UNITED STATES PATENTS 1,532,118 4/1925 Bayles 415/183 2,112,608

3/1938 Schmidt 415/183 2,306,742 12/1942 Moody 415/183 2,640,470 6/1953 Haltenberger..... 138/39 3,425,189 2/1969 Haselmayern. 138/37 3,494,379 2/1970 Hinden 138/39 FORElGN PATENTS OR APPLlCATlQNS 387,935 1/1924 Germany 138/39 1,228,223 4/1971 Great Britain 138/39 1,267,149 6/1961 France 415/208 1,019,045 11/1957 Germany 1,049,367 10/1953 France 415/208 Primary Examiner-Henry F. Raduazo Attorney, Agent, or Firm-Michael S. Striker [57,] ABSTRACT A tubular curved conduit body is provided with an inlet and an outlet, the latter to be connected with the intake of a centrifugal pump. One or more guide vanes extend across'the passage of the conduit intermediate the inlet and outlet and are each composed of two sections fast with the conduit body at diametrally opposite locations and having inner ends which extend toward but are spaced from one another.

2 Claims, 4 Drawing Figures SUCTION BEND CONDUIT FOR USE WITH CENTRIFUGAL PUMPS BACKGROUND OF THE INVENTION The present invention relates to conduits, and in particular to suction bend conduits for use with centrifugal pumps. Still more particularly the invention relates to a suction bend conduit for use with centrifugal pumps having a high system pressure.

Suction bend conduits for use with centrifugal pumps are known per se. Their purpose is to be connected with the intake of the pump, so that the fluid for the pump is supplied through the suction bend conduit. The particular reason for the provision of such suction bend conduits is to reduce the flow losses and/or to equalize the flow speed profile of the fluid as it issues from the suction bend conduit into the pump. For this purpose the suction bend conduits according to the prior art are provided with guide vanes which deflect the fluid and cause it to change its direction during the movement of the fluid through the suction bend conduit. Particularly where centrifugal pumps with high speed operation are used, where for structural reasons a suction bend conduit of identical inlet and outlet cross section must be arranged immediately upstream of the pump intake, it is necessary to provide guide vanes in the suction bend conduit in order to avoid damage to the pump resulting from vibrations and also to avoid lossesin'the operational effectiveness. Here, again, the guide vanes equalize the full speed profile of the fluid as it issues from the suction bend conduit into the intake of the pump.

However, while these guide vanes thus are advantageous in certain applications, there are also situations where they can be disadvantageous. In particular, these guide vanes have drawbacks if they are used in suction bendconduits which are under high internal pressure and if the guide vanes are either arranged in form of a grid of intersecting guide vanes or under some circumstances even if the guide vanes all extend in one and the same direction across the passage of the suction bend conduit. The reason for this is that there develops the so-called tie rodeffect which causes locally high crest peaks in the wall of the suction bend conduit. In addition to-this difficulties exist -by comparison with the manufacture of a suction bend conduit without guide vanesin making suction bend conduits which are provided with such guide vanes because the guide vanes can be inserted and welded to the suction bend conduit only after the two sections of which such suc tion bend conduits are usually made, have already been welded together.

Yet, suction bend conduits with guide vanes are of importance, for instance they are used in the main cooling fluid conduits for the pumps in atomic reactors where the safety requirements are particularly high. To meet these safety requirements which are intended to assure against damage or malfunctioning of the pumps, the use of suction bend conduits provided with guide vanes is essential because the cross-section of the pump intake and that of the fluid supply conduit must for safety reasons be no greater than the cross section of the suction bend conduit outlet, and because furtherthe amount of cooling fluid (usually water) which is present in the conduits.

SUMMARY OF THE INVENTION It is a general object of the present invention to overcome the disadvantages of the prior art.

More particularly it is an object of the present invention to provide an improved suction bend conduit of the type here under discussion, which is provided with one or more guide vanes but avoids the disadvantages of the prior art.

In pursuance of these objects, and of others which will become apparent hereafter, one feature of the invention resides in a suction bend conduit for use with centrifugal pumps, comprising a tubular curved conduit body having an interior passage provided with an inlet and with an outlet which is adapted to be connected with the intake of a centrifugal pump. At least one guide vane is also provided, extending across the passage intermediate the inlet and the outlet and being composed of two sections having respective outer end portions fast with the conduit body and inner end portions which are spaced from one another in direction transversely of the passage.

In other words, the guide vane or vanes are not of one piece but of two, being transversely subdivided. This measure assures that the tie rod effect is eliminated. Moreover, the manufacture of this suction bend conduit can now be effected in the same manner in which suction bend conduits without guide-vanes are produced, because each guide vane section can be welded into a respective suction bend conduit half before the two halvesofthe conduit are welded together.

It is further possible not only to provide a single guide vane, but a plurality of guide vanes which are spaced from one another in the longitudinal direction of the passage of the suction bend conduit, whereby additional'advantages can be obtained. In particular, the thickness of the guide vanes can be determined by appropriate profile configuration of the guide vanes, in accordance with considerations of vibratory problems without having to accept hydrodynamic disadvantages. By contrast, the known grid-shaped arrangement of the guide vanes limits the thickness of the guide vanes due to hydrodynamic considerations resulting from the construction effect of grid-shaped arrangements.

The novel features which are considered as characteristic for the invention are set forth in particular in more the suction bend conduit must be located immediately upstream of the pump to reduce to a minimum the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic plan view, partly shown in phantom lines, illustrating an embodiment of the invention;

FIG. 2 is a section taken on line A-B of FIG. 1;

FIG. 3 is a diagrammatic axial section through a further embodiment of the invention; and

FIG. 4 is an end view of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing firstly the embodiment in FIGS. 1 and 2 it will be seen that here a suction bend conduit is illustrated having an inlet portion 1 and an outlet portion 3. In other words, the inlet portion 1 would'be connected with a suitable supply of fluid and the outlet portion 3 would be connected with the intake of a centrifugal pump. Located in the suction bend conduit 1, 3 are transversely extending guide vanes 2 which are curved in the direction of fluid flow in order to impart an appropriate flow to the fluid. In accordance with the invention, and as shown particularly in FIG. 2, each of the transversely extending guide vanes 2 is composed of two guide vane sections 2 one of which is secured by welding or otherwise to the wall of the suction bend conduit at one side and the other of which is secured to the same wall at the diametrally opposite side. The sections 2 have inner free ends which are located adjacent one another but are spaced. In other words, and as shown in FIG. 2, the free ends of the sections 2' are not connected but define with one another a gap.

A further embodiment is illustrated in FIGS. 3 and 4 where the suction bend conduit is shown as having a plurality of transversely extending guide vanes 2a, 2b and 20. Of course, the number may vary but it will be noticed that here again they extend transversely of the interior of the suction bend conduit intermediate the inlet end 1 and the outlet end 3, being spaced longitudinally of one another along the elongation of the suction bend conduit. In accordance with the invention, and as shown in FIG. 4, each of the guide vanes (only the guide vane 2a is shown in FIG. 4) is composed of two guide vane sections 2'a which again define with their inner free ends a gap, meaning that these inner free ends are not connected with one another.

It will be appreciated that only a single guide vane 2 or 2a could be provided, for instance in the embodiment of a normally configurated and particularly advantageous suction bend conduit as shown in FIGS. 3 and 4, but that the number of guide vanes may be selected in accordance with the requirements of a given application.

In resorting to the present invention it is particularly advantageous that the curved configuration of suction bend conduits without guide vanes, can be employed in suction bend conduits provided with guide vanes according to the present invention. It is well known that in conventional suction bend conduits having guide vanes a sufficient fluid deflecting effect can be obtained with low flow losses only if -given the configuration of the guide vanes in grid-shaped mannerthe suction bend conduit is composed of three sections, namely an inlet section, an outlet section extending at right angles to the inlet section and an intermediate section which is welded together with the inlet and outlet sections and interposed between them. The grid of guide vanes is welded into the intermediate section. The difficulty with this prior art arrangement is that there are disadvantages involved in such a construction, particularly with respect to the structural strength which can be obtained, because a substantial stress concentration develops in the intersecting lines of the respective conduit sections. This-is avoided with the construction according to the present invention, as is clearly evident from FIGS. 3 and 4.

A further advantage according to the present invention is the fact that if the suction bend conduit has a relatively substantial internal diameter, and'is interposed in a conduit sufficiently large to permit entry of a human operator, the invention makes it possible for the operator to enter and pass through the suction bend conduit itself as long as the suction bend conduit has an internal diameter of approximately 800 mm or more.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other thpes of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a suction bend conduit for use with centrifugal pumps, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A suction bend conduit for use with pumps, particularly centrifugal pumps, comprising a tubular conduit body having an interior passage, said conduit body including an inlet part for the admission of a fluid flowing in a first direction, an outlet part for the discharge of said fluid in a different second direction, and an intermediate part for changing the direction of flow of said fluid from said first direction to said second direction, said outlet part being adapted to be connected with the intake of a pump; and at least one row of guide vanes extending across said passage in said intermediate part and each vane being arcuate in a sense between said first and second direction so as to aid in changing the direction of flow of said fluid, each guide vane in said row of guide vanescomprising two separate sections having respective outer end portions fast with said conduit body and inner end portions which are spaced from one another in a direction transversely of said passage so as to define a gap, and said sections having a combined length in transverse direction of said passage which exceeds the width of said gap.

2. A suction bend conduit as defined in claim 1; wherein said conduit being an arcuate bend between said first and said second direction, and said row of vanes being positional along said bend between said first and said second direction.

Claims (2)

1. A suction bend conduit for use with pumps, particularly centrifugal pumps, comprising a tubular conduit body having an interior passage, said conduit body including an inlet part for the admission of a fluid flowing in a first direction, an outlet part for the discharge of said fluid in a different second direction, and an intermediate part for changing the direction of flow of said fluid from said first direction to said second direction, said outlet part being adapted to be connected with the intake of a pump; and at least one row of guide vanes extending across said passage in said intermediate part and each vane being arcuate in a sense between said first and second direction so as to aid in changing the direction of flow of said fluid, each guide vane in said row of guide vanes comprising two separate sections having respective outer end portions fast with said conduit body and inner end portions which are spaced from one another in a direction transversely of said passage so as to define a gap, and said sections having a combined length in transverse direction of said passage which exceeds the width of said gap.

2. A suction bend conduit as defined in claim 1; wherein said conduit being an arcuate bend between said first and said second direction, and said row of vanes being positional along said bend between said first and said second direction.

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