Fluid handling – Processes – Cleaning – repairing – or assembling
Reexamination Certificate
1999-05-04
2001-03-27
Chambers, A. Michael (Department: 3753)
Fluid handling
Processes
Cleaning, repairing, or assembling
C137S315240, C251S113000, C251S308000
Reexamination Certificate
active
06206024
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to valves, and, more particularly, to an improved valve system that permits relatively easy assembly, disassembly and reassembly of the valve.
A variety of valve designs and configurations are available for use for material handling requirements, particularly for industrial applications. Numerous design criteria and operational parameters are required for the valves in such industrial applications.
Such industrial disc valves can be used for food, pharmaceutical, nuclear or toxic chemical applications. As such, the valve must be compatible with a wide variety of materials, some of which may be sticky, gummy, abrasive, granular, pelletized, and/or possess other troublesome characteristics. Handling of such materials through the valve over time typically results in fouling, jamming, leakage or other problems, which in turn results in poor valve performance. Importantly, the valve must be reliable to provide smooth and efficient operation without damage to the material flowing there through when in an open or partially opened configuration.
One type of valve currently available for industrial use is referred to as a disc valve in which a movable valve member, typically in the shape of a disc, is pivotally mounted within the bore or opening in a valve body. In a fully closed configuration, the disc is in sealing contact with a peripheral portion of the bore formed in the valve body to prevent the flow of material through the valve, and in a partial or fully open configuration, the valve disc is pivoted to permit the partial or full flow of material through the valve. An actuator, which may be pneumatic, manual or otherwise, is coupled to the shaft on which the disc valve member pivots for opening and closing of the valve.
Due to the nature of many of the materials being handled by industrial disc valves, such as sticky, gummy, abrasive or similarly characterized materials, periodic cleaning of the valve is required. Such periodic maintenance generally requires removal, disassembly, and cleaning of the valve, and any other sanitization. Optimally, the downtime of the system in which the valve is utilized should be minimized to avoid an excessive and detrimental economic impact to the industrial or other production cycle and maintenance manpower costs.
In many instances, industrial disc valves utilized in food, pharmaceutical, nuclear or toxic chemical environments are operated in highly restrictive, clean room, limited access or other specialized environments. As such, operators that service such systems must wear protective clothing, uniforms, gloves, goggles and other equipment to avoid contamination of the processed materials and/or potential injury and harm to themselves. Such protective clothing, particularly gloves, render it very difficult and cumbersome to easily, efficiently and quickly assemble and disassemble industrial equipment such as a disc valve. Moreover, the improved operational performance and efficiency of the disc valve is the purpose for the maintenance in many instances in the first place, and must not be compromised upon reassembly of the components. For example, accurate positioning of the components of the disc valve relative to one another, and associated clearances or tolerances must be maintained, for optimal operation as previously described. Under such conditions, the precise reassembly of known disc valves after cleaning is difficult, as the accurate and precise manipulation of the needed tools and valve components is required.
Therefore, there is a need for an improved disc valve for industrial applications which can be easily and conveniently disassembled and reassembled, preferably without the use of hand tools even by an operator wearing protective clothing and gloves while still maintaining exacting operational parameters of the valve after that disassembly and reassembly.
SUMMARY OF THE INVENTION
These and other objectives of the invention have been attained by an improved valve assembly which is capable of being entirely disassembled and reassembled manually without the benefit of tools or other potentially cumbersome and difficult to manipulate instruments. Moreover, upon reassembly of the disc valve of this invention, the disc valve member is automatically centered relative to a bore in the valve body, thereby providing proper clearance and tolerance for reliable and consistent operation of the valve upon reinstallation into the material handling system.
In a presently preferred embodiment, the valve assembly according to this invention includes a valve member in the form of a dome-shaped disc having a pair of projecting valve arms. The disc is housed within the bore of a valve body, and is mounted for pivotal movement therein on a pair of respective shafts coupled to the valve arms. The shafts are seated within holes in the valve body for rotational movement, and one of the shafts is coupled to an actuator for selective rotation of the shafts and, thereby, pivotal movement of the disc within the valve body to and between closed and opened positions.
Each shaft preferably includes a spline portion located adjacent to an annular recess on the shaft. A shoulder or detent borders the annular recess. Each valve arm includes a spline hole to receive therein the spline portion of one of the shafts for releasably coupling the valve arms to the respective shafts and, thereby, transmitting the rotation of the shaft to pivot the disc within the valve body. Importantly, the shoulder or detent adjacent to the annular recess on each of the shafts engages or abuts against the valve arm for accurately and precisely positioning the disc relative to the valve body and bore. As such, upon reassembly of the valve the disc is automatically and accurately positioned relative to the valve body without adjustment or calibration by the user.
Each shaft is preferably secured to the valve body by a shaft retainer plate. The shaft retainer plate is secured to the valve body by a plurality of bolts and thumb screws for easy manual installation and removal of the shaft retainer plates without the benefit of hand tools.
Another important feature of the present invention in a preferred embodiment is the ease and expertise with which each of the components of the valve assembly can be securely assembled together. A valve seat is releasably coupled to the valve body in sealing engagement with the disc valve in a closed position to thereby effectively and reliably prevent the flow of material through the valve. The valve seat is sandwiched between a portion of the valve body and a seat retaining ring. The seat retaining ring and valve seat are securely clamped to the valve body during assembly and reassembly by a clamp ring which includes a pair of semicircular members pivotally coupled together. When the clamp ring is installed onto the valve body and seat retaining ring, it surrounds a perimeter of the seat retaining ring and a portion of the valve body, thereby clamping the two members together with the valve seat there between. The clamp includes a manually operable latch for easy and convenient manipulation and operation during disassembly and reassembly of the valve. The clamping force produced by the clamp of this invention is at least as good as prior designs while offering significantly easier operation and use.
Accordingly, the present invention, including the valve assembly itself and the method of assembly, disassembly and use of the valve assemblies, solves the above-described disadvantages of known prior art disc valves by providing a sturdy, reliable and effective disc valve for industrial applications which can be easily and quickly assembled and disassembled, even by a user wearing a protective suit and gloves, in a timely and efficient manner. Moreover, the required clearances or tolerances of the disc valve member within the valve body are accurately and automatically achieved upon reassembly to provide for effective closure and precise opening of the valve as required during operation.
REFERENCE
Chambers A. Michael
Wood Herron & Evans L.L.P.
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