Valve assemblies

Details Valve assemblies Valve assemblies

2000-09-13

2001-09-25

Walton, George L. (Department: 3753)

Fluid handling

With leakage or drip collecting

C137S613000, C137S637200

Reexamination Certificate

active

06293300

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to valves for controlling the flow of fluids, and particularly to block-and-bleed valves assembled together to form manifolds for controlling the flow of fluids, especially liquid foods or beverages, from multiple sources to multiple delivery destinations.
The invention represents a modification of the valve assemblies used in manifold systems disclosed in U.S. Pat. No. 5,232,023 issued Aug. 3, 1993 and U.S. Pat. No. 5,450,878 issued Sep. 19, 1995.
It is common in the food packaging industry to have a need to connect a number of sources of a fluid, such as different types of milk or different types of soft drinks, to a number of different filler machines to fill containers, such as gallons, half-gallons, quarts and so on. To date these connections have been accomplished in the form of a manifold, including a number of lines from source tanks crossing a number of lines leading to filler machines, with valves being provided to control flow of fluid from any selected one or more of the source tanks to any chosen one or more of the filler machines. This arrangement creates a need for an extremely large number of valves, however. For instance, a single manifold connecting ten source tanks to ten filler machines, would use over a hundred valves to accomplish the control which is necessary and desired.
In the past, it has been conventional to use specially designed valves to control these manifolds, called block-and-bleed valves, sometimes called leak detector valves, with one such valve installed at each manifold intersection. Block-and-bleed valves are particularly applicable to the sanitary industry, because they permit control of flow of different types of fluids through the same valve with double protection against intermixing of those fluids. That is, it may be desirable to have chocolate milk flowing through one part of the valve and white milk through another part, or pasteurized milk through one part and raw milk through another part, or clean-in-place solution through one part and milk or another food fluid through another part. Clearly, it is critical that these fluids not be permitted to mix, and regulations require that even failure of a single seat or valve plug does not permit such mixing.
While valves used in the past functioned generally satisfactorily, they were extremely complex and expensive, and included multiple, coaxial, independently operable actuators and valve plugs. Under certain circumstances these valves were subject to substantial leakage and product waste, and when they did fail in this manner, while preventing mix of different fluids, their maintenance was difficult and expensive.
Even the improved systems heretofore devised have suffered from the problem that, once a valve becomes worn, the replacement of valve seats or valve plugs in a valve assembly is very time consuming and thus costly, both in terms of the cost of replacement parts and in terms of lost production due to lengthy down times during the repair process. In order to minimize down time it has been necessary to keep a large inventory of costly replacement assemblies on hand. A need has thus continued to exist for improved valve assemblies that are economical, readily repaired and which minimize waste of the fluids being conveyed.
SUMMARY OF THE INVENTION
The present invention provides a valve assembly useful in having manifold valve systems which provides individually controllable valve plugs having concentric stems and an annular ring on which valve seats are provided on each end and wherein the valve plugs and seats are removable as a single assembly. A drain or leak detector port is provided laterally to this assembly.
In accordance with one aspect of the invention, two valves are combined in a single valve housing and use independently controllable coaxial actuators while a third, leak detector valve is connected thereto by openings through the central portion of the valve seat ring and a short connecting conduit is configured so that liquid will drain by gravity from the valve assembly through the third valve to a drain which is open to the atmosphere. The invention also provides for independent control of the drain port that serves as the leak detector. An important aspect of the invention involves the use of concentrically configured or acoaxial actuator rods to enable independent control by means of independent actuators. Both actuators and valve assemblies along with the novel annular valve seat ring are readily removable as a single assembly for repair or replacement.
The invention further contemplates using one such two valve unit with a third inexpensive single actuator valve all combined together in a single subassembly to provide an inexpensive but effective valve assembly. An important advantage of the present invention results from the fact that independent control of three independently controllable valves enables closing of the inflow valve while the leak detector port remains closed to permit gravity draining of liquids out of the outflow valve, which remains open. After such draining is complete, the outflow valve can be closed and the drain port opened. Thus, no significant loss of fluid occurs when the valves are in motion. The valves of this invention are particularly effective in preventing the inadvertent mixing of different types of fluids, even on failure of one valve seat or valve plug.
An important advantage of the invention relates to the provision of an economical valve assembly that provides a leak detector, i.e., an opening to the atmosphere, which complies with applicable regulations governing equipment used in the dairy industry and yet avoids spillage of milk each time the leak detector is opened. In accordance with an important related aspect of the invention, cleaning of the valve assembly is facilitated by the fact that each valve in the assembly can be fully and adequately cleaned by virtue of the fact that each valve stem in the system can be fully extended and retracted for purposes of cleaning. This assures adequate cleaning of the valve parts and associated O-rings or similar seals.
Briefly summarized, the invention provides a valve assembly which includes a valve body formed of a cylinder having upper and lower ends with an inlet port at one end, an outlet port on an opposite end and at least one side outlet port. An annular ring element has upper and lower ends on which are formed upper and lower valve seats, respectively, the ring being sealed around its periphery on each end to the valve body. A central portion of the ring connecting the upper and lower ends has at least one and preferably about 6 to 8 openings therethrough in fluid flow communication with the side outlet port.
An actuator assembly fitted in the cylinder includes actuators, concentrically fitted actuator rods valve stems and valve plugs for opening and closing the two valve ports by engaging the valve seats on opposite sides of the ring. The rod for the upper valve seat is in the form of a hollow cylinder concentric and coaxial with the actuator rod for the lower seat, the first and second rods being independently actuatable. An independently controllable actuator assembly in the side outlet port includes a valve actuator, an actuator rod attached to and a valve plug for closing the outlet port. The outlet port, when open is in flow communication with a drain open to the atmosphere whereby liquids can be drained by gravity from the space between the annular ring and the cylinder when the side outlet is open. The actuator assembly including the annular valve seat ring is removable as a unit from the cylinder for repair or replacement.
Other objects and advantages of the invention will become apparent hereinafter.


REFERENCES:
patent: 4368753 (1983-01-01), Brakelmann et al.
patent: 5085241 (1992-02-01), Mieth
patent: 5152320 (1992-10-01), Zimmerly
patent: 5226449 (1993-07-01), Zimmerly
patent: 5232023 (1993-08-01), Zimmerly
patent: 5275201 (1994-01-01), Zimmerly
patent: 5441079 (1995-08-01), Zimmerly
patent: 5450878 (1995-0

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