US3770242A

US3770242A - Aerodynamically and hydrodynamically stable torqued butterfly valve and vane

Info

Publication number: US3770242A
Application number: US00199263A
Authority: US
Inventors: Connor J O
Original assignee: Kieley and Mueller Inc
Current assignee: Kieley and Mueller Inc
Priority date: 1971-11-16
Filing date: 1971-11-16
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06
Also published as: AU4889972A; CA974222A; GB1405270A; AU464579B2

Abstract

The vane is provided with a baffle or flow guide at the aerodynamic center to effect an approximately equal flow velocity above and below the vane at that point. The differential pressures acting on the vane are approximately balanced for a substantial angular opening portion of the vane while being of reduced magnitude up to about 80* of flow opening until reversing. The dynamic torque on the butterfly valve is substantially reduced by means of the baffle.

Description

United States Patent 1 1 OConnor, Jr. 1 1 Nov. 6, 1973 [54] AERODYNAMICALLY AND 3,000,609 9/1961 Bryant.., 251/306 HYDRODYNAMICALLY STABLE TORQUE!) 3,442,489 5/1969 Cary et al., 251/305 BUTTERFLY VALVE AND VANE FOREIGN PATENTS OR APPLICATIONS Invenor; Joseph oconnor, Jr 12,241 3/1905 Great Britain 137/5218 Goshen, NY. Primary Examiner-Henry T. Klinksiek [73] Ass1gnee: Kieley & Mueller, lnc.,

A h A. 11 t I. M1ddletovwn,N.Y. "Omey y e {22] Filed: Nov. 16, 1971 [57] ABSTRACT [21 I APPL 199,263 The vane is provided with a baffle or flow guide at the aerodynamic center to effeet an approximately equal flow velocity above and below the vane at that point. [52] US. (,l. 251/305 The differential pressures acting on the vane are [51] Int. Cl. Fl6k 1 /22, F16k 39/00 proximately balanced for a Substantial angular Opening [58] Fleld of Search 251/283, 305-308 portion of the vane while being of reduced magnitude up to about 80 of flow opening until reversing. The dyv [56] References cued namic torque on the butterfly valve is substantially re- UNITED STATES PATENTS duced by means of the baffle. 2,114,168 4/1938 Auger 251/305 15 Claims, 8 Drawing Figures 3,485,476 12/1969 Hemphill 251/283 2,596.787 5/1952 Ottinger..... 251/305 X 12/1937 Moss ..L t. 251/283 AERODYNAMICALLY AND HYDRODYNAMICALLY STABLE TORQUED BUTTERFLY VALVE AND VANE This invention relates to a butterfly valve and particularly to a butterfly valve vane.

Itis known that a hydrodynamic torque is imposed on a butterfly valve vane when the vane is in an open position relative to a flow which tends to close the vane. For example, for a vane whichv rotates in a counterclockwise direction from a closed vertical position to an open horizontal position and .for a fluid flow from left to right, a closing torque is imposed upon the vane up :to the horizontal position due to a differential pressure imposed upon the vane by the flow passing over and under the vane. Because of this, the mechanism which rotates the vane from the closed to the opened position, must be constructed to overcome the closing torque while at the same time being constructed so as to operate smoothly when the vane is to be moved into the closed position. That is, when a vane is being moved from the closed to the open'position, the drive mechanism must impose a force equal to that necessary to normally rotate the vane plus the force neededto overcome the closing torque .exertedby the fluid flow. Upon closing, the mechanism need only provide a force equal to the difference of these two forces.

However, as the closing torque on the vane has been of relatively substantial magnitude, the drive mechanism has been of substantialbulk in order to create the necessary drive, especiallywhen compared to the drive force needed to close the valve.

In order to reduce the closing torque on a butterfly vane and thus reduce the bulk and expense for the drive mechanism which is required to rotate thevane, it has been proposed to provide fins or flanges on the vanes to counterbalance the closing torque. For example, it has been known to provide a lip or flange at the periphery of a vane on the downstream end of the vane on the side facing the flow. In such a position, the fin has been used to create a drag force on the vane which tends to open the vane and which is opposte to the closing torque. Other constructions have also been proposed wherein the vane has been provided with various cross-sectional shapes in the direction of flow or combinations of fins to create the counterbalancing force.

The various vanes which have been proposed have,

however, required specific time consuming manufacturing techniques which have led to a relatively expensive vane construction. Furthermore, in some cases, for example, where the fins project from the. periphery of the vanes, there is a danger-of cavitation occurring during opening of a butterfly valve utilizing such a vane. Still further, the closing torque caused by the fluid flow has not been entirely compensated and, at various opening angles, the torque remainsrelatively'high.

Accordingly, it is an object of this invention to provide a butterfly valve vane which permits a relatively great reduction in the closing torque imposed by a fluid flow.

It is another object of this invention to provide a butterfly valve vane which can be constructed in a simple manner at relatively small costs to reduce closing torque forces thereon during use.

It is another object of the invention to provide a butterfly valve of low closing torque value.

Briefly, the invention provides a butterfly valve with a vane which is provided with a developed surface on one side which provides a means for permitting an approximately equal flow of velocity on opposite sides of the vane with the vane in an opened position. The developed surface is. in the form of a baffle which is lo cated at the aerodynamic center of the vane relative to the flow and which faces into the flow. That is, for a flow of fluid from left to right and for a counterclockwise rotation of the-valve from the closed to the opened position, the baffle is placed on the upstream side of the flow facing face of the vane. The vane is of otherwise conventional structure. For example, the Vans can have a curvilinear, e.g. a circular periphery and be of a pre-' determined-diameterLIn addition, a 'boss extends diametrically across the vane and is provided with a hollow bore so as to receive a shaft by means ofwhich the vane can be rotated within a valve housing. The baffle which is located to the oneside of the vane .is formed of a maximum thickness of 14 percent of the diameter of the vane and extends from the boss towards the periphery of the vane .so that the outer edge of the baffle corresponds to the arcuate shape of the periphery of the vane.

The developed surface is such that a flow of fluid passing over the vane is caused to flow with equal ,velocity on both sides of the vane fora significant opening angle of the vane. In this way, no torque is imposed on the vane which would tend to close the same. i

, It has been found through testing that for a baffle having a thickness which is equal to approximately 14 percent of the diameter of the vane that a closing torque does not begin to develop until the vane has been opened approximately 30. The closing torque begins to build up until the vane reaches a opened position. Thereafter, the torque begins to decrease rapidly and reverses at a point of about of opening. In order to avoid any detrimental effect from such a reversal, the vane is rotated only from a closed position to an 80 opened position. At the peak torque, it was found that the torque is about half the torque on a standard vane undergoing the same test, that is, a vane constructed of a circular disc having an enlarged boss extending diametrically thereacross for a shaft.

In another embodiment of the invention, the van'e can be provided with an additional surface on the same side as the baffle but on the opposite side of the boss. Such a developed surface provides for a smoother flow of ,fluid past the vane.

In the case of the additional developed surface, the above tests have shown that the closing torque does not begin to deveop until the vane has passed through approximately 45 ofopening; Further, the peak torque occurs at about the same-degree of opening and is of increased magnitude, forexample, by about 30 percent. The reversal of-the direction of the torque occurs at about the same degree of opening.

These and other objects and advantages of the invention will becomore more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a cross-sectional view taken through abutterfly valve using a butterfly valve vane according to the invention;

FIG. 2 illustrates a view similar to FIG. 1 with the vane in the closed position;

FIG. 3 illustrates a view taken on line 3-3 of FIG. 2; 1

FIG. 4 illustrates a side view of a vane constructed in accordance with the invention;

FIG. 5 diagrammatically illustrates a comparsion of the amount of dynamic torque in inch-pounds relative to the closing angle in degrees for a vane constructed in accordance with this invention and a standard vane; and

FIGS. 6 to 8 diagrammatically illustrate the closing torque relative to the closing angle o'fa vane according to the invention but oriented in different positions relative to the flow direction and direction of rotation.

Referring to FIGS. 1 to 3, the butterfly valve 10 is constructed with a valve housing or conduit 11 which provides a passage for a fluid flowing, for example, in the direction indicated by the arrow 'A. The valve housing 11 is provided with an interior seating surface 12 which conforms with the cross-sectional shape of the passage through the housing 1 1. This seating surface 12 can be formed in any suitable manner, as is known; however, for purposes of simplicity, the surface 12 is shown as a portion of the internal bore 13 of the housing 11.

In addition, the valve 10 includes a shaft 14 which is rotatably mounted within the valve housing 11 at diametric points thereof and which is connected to a suitable drive mechanism (not shown) which serves to oscillate the shaft within the housing 11. Also, a butterfly valve vane 15 is fixedly secured to the shaft 14, in known manner, to rotate therewith.

The vane 15 has an outer annular'periphery which conforms with the shape of the bore 13 of the housing. In addition, the periphery includes a sealing surface 16 at the edge which sealingly engages with the seating surface 12 of the housing 11 when the vane is in a closed position, for example, when the vane is perpendicular to the flow direction (see FIG. 2). The sealing surface 16 of the vane 15 is shown as a flat surface; however, this surface can be of any suitable shape,as is known, including a slightly rounded shape. Also, the seating surface 12 of the valve housing can be formed of a resilient material to sealingly engage with the sealing surface 16 as is known.

Referring to FIGS. 3 and 4, the vane 15 also includes a boss 17 which extends across an intermediate portion thereof about a bore 18 through which the shaft 14 passes. The boss 17, as shown in FIG. 4, projects from opposite surfaces of the vane 15 and is of greater thick ness than the thickness of the vane proper. Depending upon the installation purposes of the vane 15, the relative dimensions of the boss 17 to the thickness of the vane proper can vary in any suitable known manner.

The vane 15 is also provided with a baffle or developed surface 19 on one side which extends from an intermediate part of the boss 17 towards the periphery of the vane 15. This baffle 19 is positioned on the upstream side of the face of the vane which faces the flow. The baffle 19 has a maximum thickness or height relative to the vane 15 located at the aerodynamic center of the vane 15. That is, the maximum thickness is located at a point spaced a distance a from the peripheral edge of the vane 15 as shown in FIG. 4. This distance a is determined by the formula:

a/c 0.25 0.4 (t/c) v wherein a represents the distance from the peripheral edge to the aerodynamic center; 0 represents the diameter or chord length of the vane; and t is determined from the formula:

wherein T represents the maximum thickness of the vane, i.e. taken at the boss 17; and T represents the minimum thickness of the vane, i.e. taken at the periphery of the vane.

For example, for a vane diameter of 6 inches, a maximum thickness at the boss 17 of 1.125 inches and a minimum vane thickness at the periphery of 0.30 inches; t equals 0.712 inches, c equals 6 and a equals 1.167.

As shown in FIG. 3, the baffle 19 emanates from the boss 17 and extends outwardly to form a curvilinear edge conforming substantially to the arcuate shape of the periphery of the vane 15. This edge of the baffle 19 is spaced from the edge of the vane 15 while the maximum thickness of the baffle 19 is located in spaced relation to the boss 17. This maximum thickness is greater thanone half the thickness of the boss 17, as shown in FIG. 4, and is of a thickness of about 14 percent of the diameter of the vane 15.

The purpose of the baffle 19 is to provide a means for achieving an approximately equal flow velocity on opposite sides of the vane 15 when the vane is in an open position. For example, referring to FIG. 1, when the vane is in an open position as shown and has been rotated in a counterclockwise direction from the closed position (as shown in FIG. 2) a distance of about 40, the velocity of the flow across the underside of the vane 15 is approximately equal to the velocity of the flow across the top side of the vane 15. Thus, the differential pressure on the vane imposes a relatively small dynamic torque which would tend to close the vane. Further, as the vane 15 is moved to a greater opening an gle, such as the flow velocity on the top side increases relative to the flow velocity on the underside so that a significant differential pressure becomes imposed on the vane. This pressure,however, imposes a much lower dynamic closing torque on the vane 15 as would be the case if the vane 15 did not'have the baffle 19 thereon.

Referring to FIG; 5, a diagrammatic representation is shown for a comparison test between a standard vane and the vane 15 as shown in FIGS. 1 to 4. The curve B represents the relationship between the opening angle of a vane in degrees and the dynamic torque in inch-pounds on the vane. As shown, the peak torque for a standard vane is about 71 inch-pounds and this occursat about of opening. The curve C represents the relationship between the angle of opening and the torque on the vane 15 as described above. As shown, the maximum torque peaks at about 3 6 inch-pounds at the closing angle of about 75.

As shown in FIG. 5, the slope of the torque to opening curve C is substantially flat for a substantial distance. That is,the torque on the vane 15 does not begin to impose any significant forces on the vane 15 until the vane achieves about 40 of opening. At this point, the torque is about 3 inch-pounds. Thereafter, the torque begins to increase to about l6 inch-pounds at 60 of opening, 32 inch-pounds at 72 opening and a peak of about 36 inch-pounds at 75 of opening. Thereafter, the torque begins to drop off at a sharp rate until reversing at about 82 of opening after which the torque tends to open the valve. Because of this, the fully opened position for the vane as shown 'in FIG. 1 is limited to 80 of opening.

It can be seen that the decrease in torque on the vane 15 as compared to a standard vane is significant not only at the peak values but for openings of from about 65 to 85. y

Referring again to FIG. 5, curve D represents a vane as described above which is provided with an additional developed surface on the downstream side of the vane face facing the flow. This developed surface 20 is shown in dotted line in FIG. 4 and is formed by a flat surface between the point of maximum thickness of the boss 17 and the periphery'of the vane 15. This surface 20 serves to maintain a laminar flow across the vane surface afterpassage of the flow by the baffle 19. As shown, the torque on such a vane, does not develop until the vane has opened to an angle of about 45. Thereafter, the torque increases at a relatively steep rate until reaching a peak of about 47 inch-pounds at an opening angle of about 75. The torque then decreases at a sharp rate comforming to that of curve C and passes through the reversal of zero point at about the same opening angle of 82.

Referring to FIGS. 6m 8, various comparisons are made between vanes constructed in the manner described with respect to FIGS. 1 to 4 but oriented in different directions with respect to the direction of flow and the direction of rotation, as schematically shown in each figure. The curve E representsthe torque to opening angle relationship between the vane of FIGS. 1 to 4 with only the baffle, while the curves F represents the vanes having both the baffle and the flat laminar flow inducing surface. It can be seen that the peak values of torque are substantially greater than that for the vane constructed and oriented in accordance with the invention as shown in FIGS. 1 to 5.

The invention thus provides a butterfly valve vane which significantly reduces the torque on the vane when in an open condition. Furthermore, theflow control characteristics of the valve remain efficient as the turbulence imparted to the flow by the vane is small.

The invention further provides a butterfly valve vane which can be constructed in a simple manner and which has a relatively long life since there are no projecting fins which can be eroded by cavitation or otherwise eroded by foreign particles in the fluid flow.

Further, the invention provides a butterfly valve which requires a minimum construction of the drive mechanism needed to control the movement of the vane thereof. This results in a substantial savings with respect to the overall drive mechanism and the control mechanisms for the valves.

What is claimed is:

l. A vane for a butterfly valve, said vane having a curvilinear periphery, a boss extending across an intermediateportion thereof, and a baffle on one side of said vane extending from an intermediate said boss, said baffle having an outeredge spaced from said periphery and of substantially corresponding arcuate shape.

2. A vane as set forth in claim 1 wherein said vane has a circular periphery of predetermined diameter and said baffle is of a thickness of about 14 per cent of said diameter.

3. A vane as set forth in claim 1 wherein said baffle has a maximum thickness located in contiguous relation to said boss.

4. A vane as set forth in claim 1 wherein said baffle has a maximum thickness located in spaced'relation to said boss, said thickness being greater than one-half the thickness of said boss.

5. A valve comprising a valve body having a'passage for theflow of a fluid medium therethrough;

a shaft rotatably mounted in said body across said passage; and g a vane secured on said shaft within said passage for selectively opening and closing said passage to the 1 flow, said vane having means thereon for permitting an approximately equal flow velocity on opposite sides of said vane with said vane in an open position. v

6. A valve as set forth in claim 5 wherein said means is a baffle located on one side of said vane at the aerodynamic center of said vane.

7. A valve as set forth in claim 6 wherein said baffle is of a thickness of about 14 per cent of the diameter of said vane across said passage longitudinally of said shaft.

8. A valve as set forth in claim 6 wherein said vane includes a boss and said .shaft passes through said boss and wherein said baffle extends from an intermediate part of said boss towards the periphery of said vane.

9. A valve as set forth in claim 8 wherein said baffle has an outer edge spaced from the periphery of said vane and corresponding to the arcuate shape of said periphery. I

10. A valve as set forth in claim 8 wherein said baffle has'a maximum thickness located contiguously to said boss.

11. A valve as set forth in claim 6 wherein said baffle has an arcuate edge spaced from the periphery of said vane and projects from the plane of said vane.

12. A vane for a butterfly valve, said vane having a curvilinear periphery, an enlarged portion extending thereacross, a bore passing through said enlarged portion, and a developed surface on one side of said vane extending from said enlarged portion, said developed surface having an outer edge spaced from said periphery and disposed at the aerodynamic center of said vane.

13. A vane as set forth in claim 12 wherein said vane has a circular periphery of predetermined diameter and said developed surface is of a thickness of about 14 per cent of said diameter.

14. A vane as set forth in claim 12 wherein said developed surface is in the form of a baffle.

15. A vane as set forth in claim 12 wherein a fiat laminar inducing surface is provided between the maximum height of said boss and the periphery of said vane on the same side as said baffle.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,77o 2 1-2 Dated November 6', 1973 Inventor(s) eph O'Connor, Jr,

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 58, after "intermediate" insert ---part of--.

Column 6, line 58, change ""12" to --l-- Signed and sealed this 1st day of April 1.975.

(137.42.. AttPSt:

C. ITARS ALL DAY};

RUTH C. i- ASOII Commissioner of Patents attesting Officer I and Trademarks FORM PO-105O (10-69) I USCQMWDC U.$. GOVERNMENT PRINTING OFFICE II. 0I'll,

Disclaimer 3,770,242.-J0seph OOonnm, J11, Goshen, N.Y. AERODYNAMICALLY AND HYDRODYNAMICALLY STABLE TORQUED BUTTER- FLY VALVE AND VANE. Patent dated Nov. 6, 197 3. Disclaimer filed J an. 23, 1975, by the assignee, Kieley d2 Muelle'r', Inc. Hereby enters this disclaimer to claims 3 and 10 of said patent.

[Ofiicz'al Gazette July 6, 1976.]

Claims

1. A vane for a butterfly valve, said vane having a curvilinear periphery, a boss extending across an intermediate portion thereof, and a baffle on one side of said vane extending from an intermediate said boss, said baffle having an outer edge spaced from said periphery and of substantially corresponding arcuate shape.

4. A vane as set forth in claim 1 wherein said baffle has a maximum thickness located in spaced relation to said boss, said thickness being greater than one-half the thickness of said boss.

5. A valve comprising a valve body having a passage for the flow of a fluid medium therethrough; a shaft rotatably mounted in said body across said passage; and a vane secured on said shaft within said passage for selectively opening and closing said passage to the flow, said vane having means thereon for permitting an approximately equal flow velocity on opposite sides of said vane with said vane in an open position.

8. A valve as set forth in claim 6 wherein said vane includes a boss and said shaft passes through said boss and wherein said baffle extends from an intermediate part of said boss towards the periphery of said vane.

9. A valve as set forth in claim 8 wherein said baffle has an outer edge spaced from the periphery of said vane and corresponding to the arcuate shape of said periphery.

10. A valve as set forth in claim 8 wherein said baffle has a maximum thickness located contiguously to said boss.

15. A vane as set forth in claim 12 wherein a flat laminar inducing surface is provided between the maximum height of said boss and the periphery of said vane on the same side as said baffle.