Patent Application
20070256740
The present invention relates to split flapper check valves and, more particularly, to a split flapper check valve that has reduced wear of a torsion spring implemented therein.
Split flapper check valves may be used in any one of numerous circumstances in which air flow may need to be regulated. In one example, the valve is implemented in an air distribution system. Typically, the air distribution system includes an inlet duct that receives air from an air source and two or more outlet ducts that exhaust the received air to a desired area within the aircraft, such as, for example, to an aircraft cabin or an underfloor section of the aircraft. The valve is disposed between the inlet and outlet ducts to prevent reverse flow in the air distribution system by moving between open and closed positions.
Generally, the valve includes a valve body having an opening formed therethrough, a shaft that extends across the opening, two valve plates rotationally mounted on the shaft via lugs, and a torsion spring also mounted on the shaft between the lugs. The ends of the torsion spring are coupled to the two valve plates. During operation, when the valve is in the closed position, the torsion spring maintains the valve plates seated against the valve body. When airflow impinges on an upstream side of the valve plates, one or both of the valve plates unseat from the valve body to allow air to flow through the valve body opening.
Although split flapper check valves, such as the one described above, generally operate safely and reliably, these valves can exhibit certain drawbacks. For example, in some cases, the torsion spring may have a length that is less than the distance between the lugs. As a result, the torsion spring position may shift during operation and may undesirably abrade against the shaft, lugs, or the valve plates. In addition, since the torsion spring reacts the closing torque against the hinge pin, wear of the spring against the hinge pin may occur when the flappers rotate to the open and closed positions. Consequently, the spring and/or the valve plates may prematurely wear and may need to be repeatedly replaced.
Accordingly, there is a need for an improved split flapper check valve configuration that includes a torsion spring that does not abrade against the shaft or valve plate. In addition, it is desirable for the valve to be relatively inexpensive to implement. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
The present invention provides a split flapper check valve that includes a torsion spring wear reduction mechanism to at least inhibit the torsion spring from abrading against the shaft or valve plate.
In one embodiment, and by way of example only, a split flapper check valve includes a valve body, a shaft, a first valve plate, a second valve plate, a torsion spring, a first bushing, and a second bushing. The valve body includes one or more flow passages formed therethrough. The shaft is coupled to the valve body. The first valve plate is rotationally mounted on the shaft, and includes a first lug extending therefrom that has a shaft opening formed therethrough through which the shaft extends. The second valve plate is rotationally mounted on the shaft, and includes a first lug extending therefrom that has a shaft opening formed therethrough through which the shaft extends. The second valve plate first lug is spaced apart from the first valve plate first lug. The torsion spring is mounted on, and surrounds at least a portion of, the shaft between the first and second valve plate first lugs, and has at least a first end and a second end. The first bushing is mounted on the shaft and has an axial section and a radial section. The axial section is disposed between the torsion spring and the shaft, and the radial section extends radially outwardly from the axial section and is disposed between the torsion spring first end and the first valve plate first lug. The second bushing is mounted on the shaft and has an axial section and a radial section. The axial section is disposed between the torsion spring and the shaft, and the radial section extends radially outwardly from the axial section and is disposed between the torsion spring second end and the second valve plate first lug.
Other independent features and advantages of the preferred split flapper check valve torsion spring reduction mechanism will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
Turning now to
The valve plates 108, 110, as alluded to above, are configured to move between an open position to unseal the one or more flow passages 124, and a closed position to substantially seal the one or more flow passages 124. It is noted that in
During operation, the valve plates 108, 110 are preferably biased toward the closed position via a torsion spring 112. In the depicted embodiment, the torsion spring 112 surrounds at least a portion of the shaft 114, between the lugs 138, 140, 142, 144. In particular, the torsion spring 112 is coupled to one lug 138 of the first pair of lugs 138, 140, to one lug 142 of the second pair of lugs 142, 144, and contacts each of the valve plates 108, 110 to supply a torsion force that biases the valve plates 108, 110 toward the closed position. If, however, a differential pressure between the upstream faces 126, 128 and downstream faces 130, 132 of the valve plates 108, 110 exceeds a predetermined positive differential pressure value, one or both of the valve plates 108, 110 moves, against the bias of the torsion spring 112, to the open position. Before proceeding, it is noted that the torsion spring 112 may be coupled to the valve plates 108, 110, to thereby supply the torsion force thereto, in any one of numerous ways, not just by contacting each valve plate 108, 110, as in the depicted embodiment.
To maintain the torsion spring 112 in a substantially fixed position relative to the shaft 104, the bushings 114 are included. The bushings 114 are mounted on the shaft 104 and are preferably made of material that does not abrade against the shaft 104, the torsion spring 112, the lugs 138, 140, 142, 144 or any other components of the check valve 100 with which it contacts. The particular material selected depends on the materials from which the shaft 104, the torsion spring 112, the lugs 138, 140, 142, 144, and other components are constructed. In one exemplary embodiment, the shaft 104, the torsion spring 112, and the lugs 138, 140, 142, 144 are made from stainless steel; in such case, the bushings 114 may be constructed from cobalt alloys, or any other suitable material.
As shown in more detail in
The bushings 114 are disposed one each at either end of the torsion spring 112 so that the radial section 148 of each of the bushings 114 is disposed between the torsion spring 112 and an adjacent lug 138, 140. It will be appreciated that in some cases, the torsion spring 112 may be short relative to the distance between the lugs lugs 138, 140. In such case, the bushing 114 radial sections 148 may be relatively thick. In other embodiments, the torsion spring 112 may be long relative to the distance between the lugs 138, 140, or the torsion spring 112 may have relatively small inner and outer diameters and may need additional support along its length. In such case, as shown in
A split flapper check valve 100 has now been provided that includes a torsion spring that does not abrade against the shaft or valve plate. In addition, the valve to be relatively inexpensive to implement.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
