FR2515775A1 - VACUUM VALVE - Google Patents

Abstract

VACUUM VALVE WHOSE CONDUCTANCE CAN BE ADJUSTED VARIABLY; THE PASSAGE CHANNEL PRESENTING A VARIABLE CONDUCTANCE IS SHAPED BETWEEN A CYLINDRICAL BORE 2 AND A MOBILE PISTON 3 CONSTITUTED BY A CYLINDRICAL PART 4 AND BY A CONICAL PART 5.

Description

B 7013

Vacuum valve.

  The invention relates to a vacuum valve

  attractive conductance which can vary continuously and which can be adjusted reproducibly, for low and high gas flow rates. In installations for vacuum processes, very different requirements are laid down with regard to the conductance for vacuum valves.

  meet these requirements in common installations

  tes combinations of valves are used, constituted by valves having conductances of orders of

  different sizes and by bypass lines.

  For reproducible regulation of small quantities of gas, metering valves are used which

  are provided for a defined adjustment of the gas flow.

  These have a low section conductance

  which can be modified by different methods

  For example, we move pins with

  spherical or conical ends in pitch channels

  wise cylindrical or conical, which has to vary the sec-

  However, these valves can only be adjusted precisely in the

  a limited range for low conductances.

  Regulating valves are used for pressure regulation in vacuum chambers As in the case of metering valves the flow section

  is mechanically modified by displacement of a co-

  nique in a conical seat These regulating valves can also be used only for a range

limited conductance.

  For the passage of large quantities of gas, for example during the communication with air or for a rapid evacuation of a 2 - vacuum chamber, use is made of air venting valves.

different types.

  During a vacuum process, for example during a chemical attack in plasma, the conductance must be high between the vacuum chamber and the system

  pump to be able to evacuate or respectively put ra-

  quietly the room with the atmosphere On the other hand, for

  see regulate and maintain determined pressures of a 1 o gas or a mixture of gases, where the process takes place, we need adjustable conductances reproducible so

  defined The reproducibility of the setting is also

  particularly important when introducing mixtures

  gas of precisely defined composition, being given

  born that the composition depends on the conductance which is different

  specific for each of the gases As we work in

  different pressure ranges, for this purpose it is necessary to use

  read several metering or regulation valves with different conductance ranges To have reproducibly all the conductances necessary for such a process, it is therefore necessary to use a combination of several valves and types of valves and bypass lines of such devices are particularly

  expensive and critical in the case of processes where

  reads corrosive gases, since in particular the area of the gas intake system which can be reached by the gases should be kept as small as possible.

  The invention proposes to provide a sou-

  pope which allows reproducible adjustment from con-

  very low ductances up to very large conductances

  aunts, and therefore to make superfluous the setting

  work of a combination of several valves and

derivation tests.

  This problem is solved according to the invention -3- by means of a valve in which a partially cylindrical and partially conical piston moves in a

  cylindrical bore and thereby changes the conductance.

  In this way, for very small amounts of ga Z the conductance is first modified by varying the length of the passage channel which is delimited by the

  cylindrical part of the piston and by the cylindrical bore.

  For larger quantities of gas, the conductance is adjusted by varying the length and the cross section of the passage channel which is delimited by the conical part of the piston and by the cylindrical bore If the piston is no longer in the region of the cylindrical bore, the valve can still be reproducibly adjusted for large conductances or be fully open for evacuation or setting

the fast atmosphere.

  An adjustment device for reproducible adjustment of the valve is located inside the

  valve body, which avoids additional bushings

  The valve can be presented as well under the

  form of a straight valve only in the form of a valve

square.

  The present invention will be better understood a

  using the following description of two embodiments

  sation given by way of example and shown in the accompanying drawings in which: Figure 1 shows a straight valve according to the invention; and Figure 2 shows a right angle valve

according to the invention.

  In Figure 1 the vacuum valve 1 is shown

  presented in the form of a straight valve while in Figure 2 it is represented in the form of a

  angle valve A piston 3 is arranged in a

  bile in a cylindrical bore 2 This piston 3 is

  formed by a cylindrical part 4 and a conical part 5 The conical part 5 is arranged beyond the cylindrical part 4, so that when the piston 3 moves from the position shown in FIGS. 1 and 2 o it rests on a seat , first of all the cylindrical part

  4 is gradually released from the bore 2 the side part

  screw 5 remaining engaged in this bore 2 'which achieves

  the setting for low conductance values.

  Then the canic part 5 is gradually released from the bore 2, which realizes the adjustment for values

  relatively important conductance Finally the pis-

  tone 3 emerges entirely from bore 2, which makes it possible to obtain a very high conductance, therefore very high gas flow rates As long as the cylindrical part

  4 of piston 3 is inside the cylinder bore

  drique 2, which is the case for relatively low flow rates, the conductance varies because the length of the passage channel defined between the cylindrical bore and the cylindrical part of the piston varies At higher flow rates, when the piston 3 leaves the bore, the conductance varies because the length and the cross section of the part of the passage channel, which is formed between the cylindrical bore 2 and the conical part of the piston 3, varies The position of the valve can be adjusted by reproducibly by means of an adjustment device 6 which is entirely inside the body

valve 1.

- 5 -5-

Claims (8)

  1 Vacuum valve whose conductance can be variably adjusted, characterized in that the passage channel having a variable conductance is formed between a cylindrical bore (2) and a movable piston (3) consisting of a cylindrical part (4) and by a conical part (5).   2 valve according to claim 1, charac-   terized in that for low gas flow rates the piston (3) moves in such a way that the conical part (5) remains inside the bore (Z), the conductance varying as a function of the length of the part of the passage channel   which is delimited by the cylindrical bore (2) and the part   cylindrical tie (4) of the piston (3).   3 valve according to claim I or 2, characterized in that for relatively low gas flow rates   important, the piston (3) moves so that the   tapered tie 5 gradually emerges from bore 2, the conductance varying according to the length and the cross section of the part of the passage channel   which is delimited by the cylindrical bore (2) and the part conical tie (5) of the piston (3).   4 valve according to claim 1, charac-   terized in that to adjust the conductance for d-   large gaseous bits, the piston (3) is completely   out of the cylindrical bore (2).   5 Valve according to any of the   Vendications 1 to 4, characterized in that the position of the piston (3) can be adjusted reproducibly at   by means of an adjustment device (6).   6 Valve according to claim 5, charac-   in that the adjusting device (6) is located   fully inside the valve. 6 -   7 Valve according to any one of the re-   vendications 1 to 6, characterized in that it occurs in the form of a straight valve.   8 Valve according to any one of claims 1 to 6, characterized in that it presents   in the form of a angle valve.