Background and Objects of the Invention
Butterfly type valves have long been known and are commonly used in industry. With a butterfly or any other type valve it is frequently desirable to expeditiously determine the integrity of the valve when it is in the closed position, that is, to determine as a certainty whether or not the valve is permitting leakage of fluid or gases past it.
In many industrial applications integrity of valve closure is assured by placing two valves in series. The valve closure members may be coupled together for simultaneous action. When the coupled valves are closed a line between the valves can then be tapped and by measuring pressure or otherwise it can be determined as a certainty that no fluid flow is taking place past the valves.
The use of series valves is an expensive procedure. Not only does it double the valve cost to provide this leakproof assurance, but the coupling of the valve for simultaneous action is an additional expense.
The present disclosure is directed towards a valve of the butterfly type having all the inherent advantages of a butterfly valve, including simplicity, economy, dependability and so forth, while at the same time providing an inexpensive means of assuring the integrity of the valve.
It is therefore an object of this invention to provide a valve of the butterfly type having economical and inexpensive means of readily indicating leakproof closure of the valve.
Another object of this invention is to provide a valve of the butterfly valve type including a valve disc having plural sealing means in combination with provisions in the valve body for venting the space between the disc seals to provide an indication of the leakproof closure of the valve.
These objects as well as other and more specific objects of the invention will be fulfilled in the following description and claims, taken in conjunction with the attached drawings.
Description of Views
FIG. 1 is an end view of a butterfly valve embodying this invention, the valve being shown in the fully opened position.
FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG. 1 but showing the valve in the closed position.
FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG. 2.
FIG. 4 is a view as shown in FIG. 1 but showing an alternate embodiment of the invention.
FIG. 5 is a cross-sectional view taken along the line 5--5 of FIG. 4 but showing the valve in the closed position.
FIG. 6 is a cross-sectional view taken along the line 6--6 of FIG. 5.
Summary of the Invention
A valve having integrity assurance means including a valve body having a flow passageway therethrough, a disc mounted in the flow passageway, means extending through and externally of the body to controllably position the disc so that in one position it is open to permit flow of fluid through the valve to either side of the disc and in the other position it contacts the valve body around the full circumferential periphery to close against fluid flow, the disc having spaced apart parallel circumferential sealing means around the periphery thereof engaging the valve body to provide two separate spaced apart sealing engagements with the valve body, and the body having a small diameter test opening extending externally of the valve and communicating with the area between the sealing contacts when the disc is in the fully closed position providing means to indicate that the valve is not leaking.
Detailed Description
Referring to the drawings and first to FIGS. 1, 2 and 3, a butterfly valve embodying the principles of this invention is illustrated. The valve includes a body 10 usually made of metal, the body having a flow passageway 12 therethrough. Integrally formed with the body is a top stem housing 14 and a lower stem housing 16.
Positioned in the valve flow passageway 12 is an elastomeric seat member 18. Rotatably positioned within the seat member 18 is a valve disc 20 having a circumferential sealing surface 22. Positioned on the sealing surface 22 is a first increased diameter circumferential sealing ridge 24 and a second, spaced apart, paralleled, increased diameter circumferential sealing ridge 26. The spaced apart sealing ridges 24 and 26 provide a circumferential valley 28 therebetween.
The disc 22 has an upper boss 30 which is engaged by the lower end of a valve stem 32 rotatably and sealably positioned in a valve stem opening 34 contained in the top stem housing 14. The upper end 32A of the valve stem extends externally of the valve to provide means of rotatably positioning disc 20.
Positioned in the lower stem boss 16 is a lower stem opening 36 having a lower stem 38 therein, the upper end of which rotatably engages a disc lower boss 40.
The elastomeric seal member 18 has an internal circumferential sealing surface 42. Formed in the valve body 10 is a small diameter test opening 46 and, in like manner, formed in the elastomeric seat member 18 is a test opening 48, the openings 46 and 48 being in communication with each other. As shown in FIG. 3, the opening 46 may communicate with a larger diameter threaded opening 50 receiving a pipe 52. The small diameter test opening 48 in the elastomeric seat 18 communicates with the sealing surface 42 between the disc sealing ridges 24 and 36 when the disc is in the fully closed position. It can be seen that when the disc is in an opened position, such as shown in FIG. 1, the test opening 48 is exposed to fluid pressure within the valve. To close the test opening a small valve 54 (FIG. 3) may be placed in pipe 52. To indicate the efficacy of the valve when in the closed position, gauge 56 may be placed in series with pipe 52.
When the valve is in the fully closed position, as shown in FIGS. 2 and 3, fluid flow through the valve is blocked by the sealing contact of the first disc sealing ridge 24 as well as by the second disc sealing ridge 26. That is, two separate sealing engagements are provided between the disc 22 and the valve seat 18. The valley area 28 between the sealing ridges 24 and 26 is not subjected to fluid flow if the sealing contact provided by ridge 24 and ridge 26 are functioning to provide complete closure of the valve. When the valve is subjected to fluid pressure and when in a closed position, the integrity of the valve can be checked by opening the small valve 54. Valve 58 may then be opened exposing the valley area 28 between the sealing ridges 24 and 26 to atmosphere. Small valve 58 may then be closed. If leakage occurs in the valve permitting fluid to flow past one or the other of the sealing ridges 24 and 26 into the valley area 28, pressure will build in the valley area. This pressure is transmitted through test openings 46 and 48, pipe 52, and valve 54 to gauge 56. By observing gauge 56 an operator can then determine whether or not the valve is leaking.
Various other means may be provided for checking leakage. A single small valve 54 may be attached to pipe 52, the valve being open to atmosphere. With the valve 54 open any leakage which occurs will cause fluid flow out through the passageways 46 and 48, pipe 52 and through valve 54, to indicate the leakage.
Another means of testing the efficacy of the valve in the closed position is to apply pressure to the test openings to raise the pressure in the valley annular area 28 to a level above the pressure to either side of the disc 20 and observe whether or not the pressure decreases, that is, whether pressure leaks off past one or the other of sealing ridges 24 and 26. It can be seen that many other different means may be provided for utilizing the features of this invention to indicate the existence or nonexistence of leakage past the valve disc.
FIGS. 4, 5 and 6 show an alternate embodiment of the invention. In these figures the valve illustrated is essentially the same with two basic differences: First, the valve body is not provided with a separate elastomeric seal but the body itself is provided with a sealing surface 60; and second, valve disc 22 has spaced apart circumferential grooves 62 and 64. Positioned in groove 62 is a seal 66 which is illustrated, as an example, in the form of an O-ring, and in like manner in groove 64 is a continuous seal 68. The seals project beyond the normal circumferential diameter of disc 22 to sealably engage the body sealing surface 60 when the disc is in closed position. Seals 66 and 68 provide the valley 28 therebetween which is communicated with by the test opening 46 in the valve body as shown in FIG. 6.
The embodiment of FIGS. 4, 5 and 6 as compared to that of FIGS. 1, 2 and 3 illustrates that the invention may be employed in different valve designs. While both arrangements illustrated herein show a butterfly valve of the slanted disc type, that is, with the plane of the disc askew of the longitudinal axis of stem 32 and stem 38, it can be seen that the principles of the invention would function the same in different butterfly valve designs. Particularly, many butterfly valves utilize an arrangement wherein the disc is in a plane parallel the longitudinal axis of the valve stem and the invention would work in exactly the same way as illustrated herein. Virtually any arrangement which provides a disc having an uninterrupted cicumferential sealing surface may be employed in practicing the invention.
To insure that fluid will not penetrate between the external circumference of seat 18 and body passageway 12, a tube 70 may be employed as illustrated in the right hand portion of FIG. 3. Tube 70 may be threaded into the valve body 10 as illustrated. It sealably contacts the elastomeric seat member 18 so that no fluid flow can occur around the external circumference of the tube. Obviously, only one or the other of the arrangements illustrated in the left or right hand side of FIG. 3 would be used, not both at the same time. Other similar refinements may be made in a valve which encompasses the invention.
While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element thereof is entitled.