US3483824A - Rotary pump with check valve - Google Patents

Description

Dec. 16., 1969 T. s. SPRAGUE ROTARY PUMP WITH CHECK VALVE Filed Sept: 15, 1987 2 Sheets-Sheet 1 FiG.

FIGJ

R E V m Theodwe SSprague BY ATTORNEY United States Patent 3,483,824 ROTARY PUMP WITH CHECK VALVE Theodore S. Sprague, Hudson, Ohio, assignor to The Babcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Filed Sept. 15, 1967, Ser. No. 668,752 Int. Cl. F0411 3/00, 15/02; F16k 15/00 US. Cl. 10389 6 Claims ABSTRACT OF THE DISCLOSURE An improved rotary pump adaptable for circulating a substantially incompressible fluid through a passageway. The pump generally comprises a housing having an extended portion adapted to extend substantially axially of a portion of the passageway. A motorized drive shaft rotates within the housing and has a free end which extends from the extended portion of the passageway. An impeller is mounted on the free end of the shaft for rotation by the shaft as the shaft rotates. A check valve is mounted on the pump housing at the suction side of the impeller.

BACKGROUND AND SUMMARY OF THE INVENTION In the course of designing a consolidated nuclear steam generator which utilizes a plurality of pumps arranged in a parallel fashion with common fluid inlet and outlet headers, it became necessary to provide for the eventuality of failure of an individual pump. Due to the parallel arrangement of the pumps, if one pump fails it is desirable to close off the passageway occupied by the impeller of the failed pump so that the remaining operating pump or pumps may continue to circulate fluid from the common inlet header to common outlet header without loss in efficiency occasioned by fluid backing up through the passageway occupied by the inoperative pump and returning to the common inlet header.

Commercially available check valve and pump configurations were investigated and found to be unequal to the task of automatically compensating for the failure condition without substantially reducing pump efl'lciencies. The disclosed inventive arrangement solves the problem in a simple and eflicient manner.

In the inventive arrangement a rotary pump is adapted to circulate fluid through a passageway having an inlet and an outlet. The inlet and outlet may be considered to be the common inlet and common outlet of a plurality of pumps arranged in a parallel fluid flow configuration one with the other. The pump is provided with an elongated housing portion which extends axially of the passageway between the inlet and outlet. The pump shaft protrudes from the housing into the passageway and an impeller is removably mounted on the free end of the shaft for rotation with the shaft. A plurality of vanes are pivoted to the housing within the passageway On the suction side of the impeller and arranged to close the passageway when fluid backs up within the passageway. For example, in the parallel arrangement, assuming one of the pumps fails, the discharge from the remaining operating pump causes the fluid in the common outlet header to back up within the portion of the passageway within which the failed pump is disposed and pivot the vanes closed. The arrangement thus closes off the passageway when a pump fails while the other pumps are operating. Additionally, when the vanes are open, as while the pump is operating, the vanes are arranged to direct the fluid substantially longitudinally of the passageway and into the pump impeller so that the pump efficiency is enhanced.

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It should be noted however that the inventive arrangement of the vanes within the passageway and with respect to the impeller is thought to be of general application to hydraulic systems. The inventive arrangement is therefore not limited to applications in nuclear reactors or parallel fluid circuits.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a pump showing the check valve closed,

FIG. 1A is a schematic view of a plurality of pumps arranged in parallel,

FIG. 2 is a partial side elevation view of the pump showing the check valve open,

FIG. 3 is a partial plan view of the check valve taken along the line 33 of FIG. 1,

FIG. 4 is a partial elevation view of the check valve taken along the line 44 of FIG. 3,

FIG. 5 is an elevation view similar to FIG. 4 showing the valve open,

FIG. 6 is a reduced plan view similar to FIG. 3 showing another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference numerals designate like or corresponding parts throughout the several views there is shown in FIG. 1, a rotary pump 10 adapted to circulate a substantially incompressible fluid through a passageway 11 having an inlet 12 and outlet 13. The pump 10 generally includes a housing 14 with an elongated annular portion 15 adapted to extend substantially axially of a portion of the passageway 11, a motorized output drive shaft 16 journalled for rotation within the housing 14 and having a free end 17 which extends beyond the annular portion 15 of the housing, an impeller 18 removably mounted on the free end 17 of the shaft 16 for rotation within the passageway 11 as the shaft rotates, and a plurality of vanes 19 pivotally mounted on the housing within the passageway 11 for motion toward and away from one another to act as a louvered check valve on the suction side of the impeller 18.

The passageway 11 to which the preferred embodiment is adapted is formed by an open-ended L-shaped conduit 20 having an elongated annular portion 20A intermediate the inlet 12 and outlet 13. However, it is understood that the passageway shown is intended to be representative of any passageway through which an incompressible fluid may be circulated and that persons skilled in the art may adapt the device to passageways of other construction Without departing from the spirit or scope of the invention. Further, the annular portion may be formed by providing a sleeve (not shown) within the passageway, as is well known in the art.

The conduit 21 has an opening 21 formed therein through which the housing 14 protrudes sufiiciently to allow the impeller 18 and vanes 19 to be positioned properly within the pasageway 11. It is seen that the housing 14 is mounted on the conduit 29 and supported in place so as to close the opening 21. In the preferred embodiment a portion of the outer surface 20F of the conduit 20 is faced to form a platform for an enlarged portion 22 of the housing 14. The enlarged portion 22, or flange, is provided with a mating surface 22F complementary to the faced surface 20F of the conduit 20 and is mounted in place on the conduit by means well known in the art to form a fluid tight seal between the mating surfaces.

As shown in FIGS. l3 the louver-type check valve is an annularly shaped valve comprising a plurality of curved vanes 19 mounted on the housing for limited rotation between an open position as shown in FIG. 2 and a closed position as shown in FIG. 1. It is seen that the vanes are substantially equidistantly spaced around the housing. As best shown in FIGS. 4 and 5, each vane 19 has a rounded leading edge 27 with a curved body portion 28 extending therefrom which gradually tapers to a trailing edge 29 remote from the leading 27. Although in the preferred embodiment the vanes are formed from sheet metal and are hollow. They may be fabricated having a solid cross-section without departing from the spirit and scope of the invention. As best shown in FIGS. 1-3, each vane 19 is freely pivotally mounted and is rotatable about an axis extending substantially radially of the axis of the annular portion 15 of the housing. The vanes 19 are individually rotatable from the closed position to the open position and returnable to the closed position in response to the flow fluid within the conduit 20.

Referring now to FIGS. 3 and 6 it is seen that each vane has a substantially straight inboard end 30 adjacent the annular housing portion 15 and a curved outboard end 31 or tip, having a curvature which corresponds to the contour of inner surface of the conduit 20. As viewed in the closed position shown in FIG. 3 in the preferred embodiment the inboard end 30 is formed substantially perpendicular to the axis of rotation of the vane, the trailing edge 29 is formed substantially parallel with the axis of rotation of the vane next adjacent to the trailing edge, the outboard end 31 is arcuately formed to describe a portion of the circumference of a circle concentric with the axis of the annular portion 15 of the housing, and the leading edge 27 is formed substantially parallel with the axis of rotation of the vane.

As best shown in FIGS. 35, the curved body portion 28 of each vane defines an upstream surface 32 remote from the impeller and a downstream surface 33 adjacent the impeller. The leading edge end of each vane had a larger cross section than the trailing edge end and has a circular recess 35 extending therethrough substantially paralel with the leading edge of the vane. A plurality of pivot pins 36 mounted on the annular portion 15 of the housing and extending radially therefrom act as supports for the vanes. Each pin 36 is a rod having one end 37 externally threaded and the other end terminated by a head portion 38. The annular portion 15 of the housing is provided with a plurality of internally threaded recesses 39 having axes oriented radially of the axis of the housing to threadably receive the pins. The vane recesses 35 are counterbored from the outboard end 31 to form enlarged recesses 38A to accommodate the head portions 38 of the pins 36. The head portions 38 hold the vanes in place for rotation about the pins and prevent the vanes from moving endwise of the pins. The head portion 38 is adapted to accommodate any driving tool well known in the art for threadably engaging the pin with the housing.

The annular portion 15 of the housing 14 is provided with a plurality of stops 40 extending radially from the housing into the passageway. The stops 40 are substantially equidistantly spaced around the housing and correspond in number of the number of vanes. Each of the stops 40 defines the extreme open position for one of the vanes.

Assuming the vanes are in the closed position shown in FIG. 3, as the impeller commences rotating, each vane commences rotation from the closed position as fluid flows against the upstream surface 32 of the vanes and continues to so rotate until the downstream surface 33 of each vane contacts the stop 40 corresponding thereto. A reversal of fluid flow within the passageway returns the vanes to the closed position. When the vanes are pivoted to the open position they are arranged to direct the flow of fluid longitudinally of the passageway. That is, the stops 40 are arranged to position the vanes .4 such that a line drawn tangent to the upstream surface 32 of a vane at the trailing edge 29 is substantially parallel to the axis of the passageway 11 and annular portion 15 of the housing 14.

Assuming the impeller is stationary, the vanes commence rotation from the open position as fluid flows against the downstream surface 33 of the vanes, and causes them to rotate until the upstream surface 32 contacts the vane next adjacent. For example, when a plurality of pumps are arranged in parallel with one another as shown in FIG. 1A; when one pump fails, fluid flow induced by the pumps in service will close the vanes. The vanes overlap one another and acts as stop one for the other, to define the closed position. It should be noted that when the impeller is stationary and if the vanes are in the open position, fluid flowing past the impeler is directed towards the downstream surface 33 of the vanes at substantialy right angles thereto to afford their rapid closure.

In accordance with the foregoing remarks it is seen that it is advantageous to correlate the design of the curvature 'of the upstream surface, the position of the stops, the angle the impeller blades describe with respect to the downstream surface of the vanes and the axial distance between the impeller blades and vanes as measured along the axis of the annular portions of the housing, to achieve a predetermined fluid flow within the portion 20A of the pasageway 11.

In the embodiment shown in FIGS. 1-3, the annular portion 15 of the housing 14 is substantially cylindrically shaped. As a result, when the vanes are in the closed position it is seen that a substantially triangular space 50 exists between the inboard end 30 of each vane and the outer periphery of the housing. Thus a limited amount of fluid flows longitudinally of the housing even when the vanes are in the closed position. However, as the number of vanes utilized is increased the summation of the incremental spaces 50 decreases and the volume of fluid flow is decreased correspondingly.

In the embodiment shown in FIG. 6 a plurality of flat surface 51 are formed on the housing. For example, the annular portion 15 of the housing 14 may be formed having an octagonally shaped outer surface to accommodate an eight-vaned configuration such that the inboard end 30 of each vane is disposed substantially parallel with respect to the outer periphery of the housing as the vane rotates. In this embodiment the aforementioned spaces 50 are substantially completely eliminated with the result that fluid flow longitudinally of the passageway is also substantially completely eliminated when the vanes are in the closed position.

What is claimed is:

1. An improved rotary pump adaptable for circulating a substantially incompressible fluid through a passageway, the pump generally comprising, a housing having a portion formed to extend substantially axially of a portion of the passageway, a motorized drive shaft rotatable within the housing, a free end of the shaft extending from the extended portion of the housing, and an impeller mounted on the free end of the shaft for rotation by the shaft as the shaft rotates, a check valve mounted on the pump housing at the suction side of the impeller for closing the passageway when fluid backs up within the passageway, the check valve being an annularly-shaped valve comprising curved vanes mounted on the housing for limited rotation in place between an open position and a closed posit1on.

2. The improvement according to claim 1 including a plurality of stops mounted on the housing to define the open position of the vanes.

3. An improved rotary pump adaptable for circulating a substantially incompressible fluid through a passageway, the pump generally comprising, a housing having a portion formed to extend substantially axially of a portion of the passageway, a motorized drive shaft rotatable within the housing, a free end of the shaft extending from the extended portion of the housing, and an impeller mounted on the free end of the shaft for rotation by the shaft as the shaft rotates, a check valve mounted on the pump housing at the suction side of the impeller for closing the passageway when fluid backs up within the passageway, the check valve comprising a plurality of curved vanes, a plurality of pins mounted on the housing and extending radially thereof each pin acting as a pivot pin for one of the vanes, the vanes having an open position in which they are arranged to direct the fluid substantially longitudinally of the passageway when impeller rotation induces fluid flow therein and having a closed position in which they are arranged to overlap one another to impede the flow of fluid when fluid tends to flow in a direction opposite to impeller induced flow.

4. In a nuclear reactor, an improved rotary pump adaptable for circulating a substantially incompressible fluid through a passageway, the pump generally comprising,

a housing having a portion for-med to extend substantially axially of a portion of the passageway, a motorized drive shaft rotatable within the housing, a free end of the shaft extending from the extended portion of the housing, and an impeller mounted on the free end of the shaft for rotation by the shaft as the shaft rotates, a check valve mounted on the pump housing at the suction side of the impeller for closing the passageway when fluid backs up within the passageway, the check valve comprising a plurality of pins mounted on the extended portion of the housing and extending radially thereof on the suction side of the impeller, a plurality of vanes, each vane being pivotally mounted on one of the pins, the vanes having an open position and a closed position, a plurality of stops mounted on the extended portion of the housing and extending radially thereof on the suction side of the impeller intermediate the impeller and pins, each stop defining the open position of one of the vanes, the vanes being arranged to overlap one another to define the closed position for each of the vanes, the vanes rotating from the closed position to the open position when the impeller induces fluid flow within the passageway and from the open position to the closed position when fluid tends to flow in the passageway in a direction opposite to the direction of impeller induced flow.

5. An improved rotary pump adaptable for circulating a substantially incompressible fluid through a passageway, the pump generally comprising, a housing having a portion formed to extend substantially axially of a portion of the passageway, a motorized drive shaft rotatable within the housing, a free end of the shaft extending from the extended portion of the housing, and an impeller mounted on the free end of the shaft for rotation by the shaft as the shaft rotates, a check valve mounted on the pump housing at the suction side of the impeller for closing the passageway when fluid backs up within the passageway and opening in response to the impeller induced flow, the check valve being an annularly-shaped valve comprising vanes freely pivotally mounted on the housing for limited rotation in place between an open position and a closed position.

6. The improvement according to claim 5 wherein each vane overlaps the next adjacent vane when they are in the closed position.

References Cited UNITED STATES PATENTS 1,683,949 9/1928 'Bergdoll. 2,459,815 1/ 1949 Hammell. 3,118,467 1/1964 Kuhn 137512.1 3,160,112 12/1964 Flaton et al. 2301 15 3,263,906 8/1966 Ward 137512.1

890,117 6/ 1908 Austin. 1,460,428 7/1923 Moody 16389 2,030,560 2/1936 Adams 103-89 2,947,466 8/1960 Busquet.

FOREIGN PATENTS 530,741 7/1955 Italy.

HENRY F. RADUAZO, Primary Examiner

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