Valves and valve actuation – With means to increase head and seat contact pressure – Fluid pressure
Reexamination Certificate
2000-08-04
2002-08-06
Doerrler, William C. (Department: 3754)
Valves and valve actuation
With means to increase head and seat contact pressure
Fluid pressure
C251S187000, C251S193000
Reexamination Certificate
active
06427973
ABSTRACT:
The present invention relates to a vacuum system with a vacuum plate valve.
Plate valves are valves in which a valve plate is driven transversely in the plane of one or more ports to be closed, and into or across the latter, and then the plate is sealed to the periphery of the port or around all of the ports.
Of course, a great variety of valves for the controlled, tight closing of ports are known, not all of them efficient, much less all of them plate valves. For example, European Patent Document, EP-A-0 590 964 (corresponding to U.S. Pat. No. 5,356,113) discloses a valve by means of which the flow from one port in an actual valve housing to a second is controlled. The valve comprises a first plate and, a parallel second plate attached by a flexible bellows. By applying pressure to the interior of the bellows the two plates are pushed apart and both are brought into sealing contact each with a margin of a port. Since the plates are not displaceable parallel to the plane of the ports, this is not a plate valve.
WO93/18322 discloses a plate valve for blast furnace air heating apparatus, which is contained in its own valve housing. Its purpose is to connect or separate from one another the ports of two coaxial pipe connections on the valve housing. For this purpose a valve plate is provided which is disposed between the pipe connections and is driven linearly parallel to the planes of the ports of the pipe connections. Hydraulic lifting devices are mounted on the wall of the valve housing, by means of which the entire valve plate is urged against the margin of one of the pipe connections lying within the housing, thus closing the pipe connection.
A similar system is shown by LU-57991. In a valve housing a valve plate is mounted and driven for linear movement over a pipe connection and it is inserted between the pipe connections and withdrawn from them again. Expandable bellows are provided on a support plate, on both sides, which are closed in each case by sealing plates. To seal off the passage through the pipe connection, the support plate with the bellows and sealing plates is pushed out of the housing and between the pipe connections, and then by a common, simultaneous expansion of the bellows, both sealing plates are urged against the ends of the pipe connection. As in EP-0 590 964, the sealing forces compensate one another by simultaneous, oppositely directed sealing. On the other hand, according to WO93/18322, the necessary sealing force is absorbed by the valve housing wall with the operating devices.
A very similar procedure is shown in NL-7604483, according to which the connection between two pipe connections is produced by the insertion of a valve plate, oppositely directed build-up of sealing pressure forms a bilateral seal at sealing pistons that is self-compensating with regard to sealing forces.
An object of the present invention to provide an arrangement for a vacuum system with a vacuum plate valve, in which the valve is to control at least one port in a wall, that is, the passage from one space on one side of the wall into a space on the other side of the wall, these spaces communicating through the port in the wall. Intervention into the connection passing through the wall and forming the port, which might possibly be interpreted as a “tubular connection,” is not to take place. With the present invention such a system is furthermore to be created in which no actual valve housing is necessary. Also, the design of the system is to be flexibly extendable such that a plurality of vacuum chamber ports or wall ports can be controlled independently of one another, i.e., simultaneously or staggered in time, by a single plate valve, and in which—especially in the case of a plurality of ports—the number of ports per closing movement is minimized. Furthermore, the valve is to be operable in both directions with a sealing pressure difference, and is also to be usable in vacuum processes on both sides.
This object is achieved according to preferred embodiments by providing a vacuum system, with a wall, at least one port in the wall and a vacuum plate valve operable to control fluid flow through the at least one part said valve comprising:
a supporting plate mounted for movement parallel to the wall, the movement path of which runs across the port;
at least one sealing plate mounted on the plate surface facing the wall for movement perpendicular to the plate surface and parallel with respect to the latter;
a sealed, expandable operating cylinder chamber between the supporting plate and the at least one sealing plate;
a pressure-medium line carried through or on the supporting plate, leading into the cylinder chamber; and
movement guides for supporting the plate with respect to the wall, said guides withstanding the sealing force thrusting back onto the sealing plate during operation.
Only on one side is one or more sealingly expandable operating cylinder chambers provided on the supporting plate, each with a sealing plate, so that by the movement of the supporting plate—a positioning movement—the one or more sealing plates are brought in alignment onto the corresponding number of ports provided in the wall. Thereafter, by applying pressure to the cylinder chambers, the sealing plates provided—at least one—are pressed sealingly against the margins of the particular ports. The resultant unilateral sealing thrust is absorbed by the means for guiding the supporting plate movement. A gaseous medium—preferably air—is used as the pressure medium for the at least one provided cylinder chamber.
It is thereby possible to move the valve plate as a whole directly along the wall containing the at least one port, until a sealing plate is positioned in each case opposite the port in the wall that is to be sealed. The minimum necessary sealing movement is limited downwardly only by the releasing movement that is necessary in order to displace the valve plate, with the sealing plate disengaged, freely along the wall. This releasing movement can be very small, but therefore the necessary sealing movement of the sealing plate or plates can also be small.
In a preferred embodiment the cylinder chamber is encapsulated, preferably in a bellows, or defined by a rubber-elastic wall. This is accomplished preferably by means of a metal bellows, a bellows with metallic and/or rubber-elastic wall part of the capsule, e.g., an air-tight rubber-elastic “bubble” in a stabilizing telescopic housing.
The rim of the port and/or the sealing plate comprises on its side facing away from the support plate, preferably at least one sealing element deforming elastically under sealing pressure, which can be formed by at least one rubber-elastic sealing element and/or by at least one metallic sealing element of appropriate dimensions.
Furthermore, the sealing plate is preferably mounted on the supporting plate with guidance of its movement, preferably in the cylinder chamber (vacuum contamination!), preferably by means of guiding rods in the cylinder chamber, preferably with clearance. It is furthermore biased against the supporting plate by returning means, e.g., by spring members. Guidance with free play promotes a tight contact, independent of tolerances, of the sealing plate against a port. Preferably, furthermore, all of the operating, guiding and biasing means etc. for the sealing plate are also encapsulated in the cylinder chamber. This assures a bilateral usefulness of the valve for vacuum processes, while preventing particle contamination of such process spaces.
In order further to assure the complete uncovering of the port in the chamber wall it is proposed that at least one opening be provided in the supporting plate, spaced apart from the sealing plate, with a size and shape the same as or larger than any port to be sealed.
Thus, it can be seen that, following the concept of the invention, only the supporting plate can be moved, preferably linearly, along a wall containing the at least one port to be controlled, to a first position in which the said port is sealingly closed by the operation of the
Bastianelli John
Crowell & Moring LLP
Doerrler William C.
Unaxis Trading AG
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