Leakfree switching process for a double-seat valve and a sealing

Details Leakfree switching process for a double-seat valve and a sealing Leakfree switching process for a double-seat valve and a sealing

1996-03-05

1998-03-31

Lee, Kevin

Fluid handling

Processes

13761411, 137242, F16K 2500

Patent

active

057327270

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to a process for leakfree switching of a double-seat valve and a sealing system for application of the process.
EP 0 039 319 B1 discloses a sealing system by means of which a process of the type described above can be carded out in approximation; this system ensures low-leakage rather than leakfree switching. In the state-of-the-art sealing system the first closure element, which is designed as a valve piston with radial sealing means, is enclosed and sealed in the area of its end section by a second closure element when the double-seat valve is in the open position; the end of the second closure element facing the valve piston has a recess with a more or less cylindrical circumferential wall whose dimensions are such that the end section of the valve piston is received and sealed during opening and in the open position, before the second closure element opens. When the double-seat valve is in the closed position, the valve piston, with its radial sealing means, has been received into a cylindrical valve seat. Provision is made here such that the cylindrical circumferential surface of the recess in the second closure element is aligned with the cylindrical valve seat and the radial sealing means on the end section of the valve piston are arranged so that they are moved during opening of the valve by the cylindrical valve seat so as to come into sealing contact with the aligned cylindrical circumferential wall of the recess as the valve opens, before the valve piston comes to rest against the second closure element.
A preferred embodiment of the state-of-the-art sealing system is shown in FIG. 2 of EP 0 039 319 B1, together with all the structural details. It is an essential feature of this sealing system that the radial sealing means are at all times supported and protected by a cylindrical circumferential wall both when the valve is in the closed position and in the open position and during the opening process and when the valve is in the open position. As the double-seat valve opens, the radial sealing means engage the circumferential wall of the recess of the second closure element, and, even when the valve is in the open position, the radial sealing means is kept engaged with the circumferential wall of the recess in the second closure element. The engagement is in this case exclusively of the nature of frictional connection, that is, the reaction forces generated in the radial sealing means during elastic deformation of these means provide exclusively for the contact pressure created between the circumferential wall and the radial sealing means, which pressure prevents entry of the pressurized fluid present at the radial sealing means into the leakage cavity between the two closure elements.
GB 668 563 discloses a valve in which radial sealing means-a so-called O ring in this case-mounted in a closure element in the form of a slide are inserted into a closure element in the form of a seat disk as the valve opens and remains there when the valve is in the open position. This older reference discloses that the cylindrical seat area active when the valve is in the closed position is made equal in diameter to that of the cylindrical recess in the seat disk. Although this valve has no leakage cavity provided between the closure elements, and the sealing system devised serves primarily the purpose of protection and support of the radial sealing means, because of deformation of the radial sealing means the frictional connection between the circumferential wall of the seat disk and the radial sealing means must be designed so that no pressurized fluid forced against this seat disk will reach the area of the recess in the seat disk situated beyond the seal.
Disadvantages are inherent in the state-of-the-art sealing systems referred to in the foregoing. A first disadvantage results from the fact that the tightness of the contact between the radial seating means involved and the associated cylindrical circumferential wall of the closure element results exclusive

REFERENCES:
patent: 4254792 (1981-03-01), Schadel
patent: 4483360 (1984-11-01), Knappe et al.
patent: 5284182 (1994-02-01), McLennan

Affiliated with

Also associated with

Rating

Leakfree switching process for a double-seat valve and a sealing does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Leakfree switching process for a double-seat valve and a sealing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Leakfree switching process for a double-seat valve and a sealing will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-44194