JPH05237361A - Valve for vacuum - Google Patents

Abstract

PURPOSE:To provide a valve for vacuum which is capable of performing main exhaust from initial exhaust while preventing disturbance of an air flow at the time of initial exhaust. CONSTITUTION:A valve 1 for vacuum is constituted as follows. In a valve mechanism, exhaust conductance is changed by change in the position of a valve element 5 for the valve seet 4. The valve mechanism is opened and driven so that exhaust conductance is increased from small exhaust conductance as an air flow reaches main exhaust from initial exhaust by the driving means 7 of the valve element. Moreover the opening speed of the valve element 5 based on the driving means 7 for the valve element is controlled by a controlling means 8. Disturbance of the air flow at the time of initial exhaust is inhibited by one piece and generation of dust is prevented by the constitution up to main exhaust from initial exhaust.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vacuum valve,
More specifically, for example, the present invention relates to a vacuum valve used for exhausting a vacuum chamber and capable of preventing turbulence of an air flow at the initial stage of exhaust.

[0002]

2. Description of the Related Art Conventionally, in the case of evacuating a vacuum chamber, conductance (flow force: the amount of air flow flowing to a certain part of the vacuum system) is used to prevent turbulence of the air flow that occurs during initial evacuation of the vacuum chamber. Was divided by the pressure difference) and two or more different types of vacuum valves were used for evacuation in the following order.

That is, first, a vacuum valve having a small conductance is opened to evacuate the inside of the vacuum chamber for a certain period of time or until the pressure in the vacuum chamber is set to a set pressure, and then a vacuum valve having a larger conductance is set. Open and continue exhausting.

[0004]

Conventionally, as described above, two or more kinds of vacuum valves having different conductances are mounted in parallel in a vacuum chamber, and the vacuum valve having a small conductance is opened at the time of initial evacuation to open the vacuum chamber. The turbulence of the air flow between the chambers was prevented. However, in the case of such a configuration, since two or more vacuum valves have to be attached to the vacuum chamber, there is a problem that the piping and the exhaust sequence become complicated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vacuum valve capable of performing initial exhaust to main exhaust while preventing turbulence of the air flow during initial exhaust. It is a thing.

[0006]

In order to achieve the above object, the vacuum valve of the present invention comprises a valve mechanism in which the exhaust conductance changes due to a change in the position of the valve body with respect to the valve seat, and the valve body from the initial exhaust. According to the present exhaust, a valve body driving means for driving the valve body to open from a small exhaust conductance to a large exhaust conductance, and a control means for controlling the opening speed of the valve body by the valve body driving means are provided.

[0007]

The vacuum valve of the present invention has the above-described structure. For example, when the vacuum chamber is evacuated, the valve body driving means changes the valve body from a small exhaust conductance to a large exhaust according to the initial exhaust to the main exhaust. Open drive to have conductance. At this time, the control means arbitrarily controls the opening speed of the valve body by the valve body drive means. By such an operation, the turbulence of the air flow during the initial exhaust can be suppressed, and the generation of dust can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vacuum valve according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a vacuum valve according to an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the opening time of the valve body and the opening degree of the valve body of the vacuum valve according to the present embodiment. .

A vacuum valve 1 shown in FIG. 1 has a boundary portion between a valve body 1A bent in an L shape, an inlet port 2 communicating with the vacuum chamber of the valve body 1A, and an exhaust port 3 communicating with a vacuum pump. A tapered valve seat 4 having a smaller diameter according to the downward direction, a valve body 5 corresponding to the shape of the valve seat 4 and completely adhered to the valve seat 4, and a valve body 5 A valve body drive means 7 that is connected to a valve body shaft 6 that penetrates the main body 1A and projects upward to the outside, and drives the valve body 5 in the direction of the arrow X shown in FIG. 1, and a valve body by this valve body drive means 7. The control means 8 for controlling the opening speed of No. 5 is provided.

By making each of the valve seat 4 and the valve body 5 tapered, the exhaust conductance changes due to the change of the position of the valve body 5 with respect to the valve seat 4. Further, the valve body driving means 7 drives the valve body 5 to open from the small exhaust conductance to the large exhaust conductance in accordance with the initial exhaust to the main exhaust. The control means 8 controls the opening speed of the valve body 5 by the valve body drive means 7 as shown in FIG.
The time during which the opening degree of 0 changes from 0% to 100% is arbitrarily controlled within the range of T1 which is the minimum to T2 which is the maximum. In addition, in FIG.
Is a seal portion of the valve body shaft 6.

Next, the operation of the vacuum valve 1 having the above structure will be described. When the vacuum chamber 1 is evacuated by the vacuum valve 1, for example, the valve body drive means 7 changes the valve body 5 from a small exhaust conductance to a large exhaust conductance in accordance with the initial exhaust to the main exhaust. It is opened and driven upward in FIG. This allows
The valve body 5 moves upward in the drawing to separate from the valve seat 4, and the atmosphere on the vacuum chamber side flows to the vacuum pump (not shown) side.
In this case, since the valve seat 4 and the valve body 5 are gradually separated, the exhaust conductance at the time of initial exhaust is small and the air flow becomes a laminar flow, and the air flow in the vacuum chamber is exhausted without disturbance.

Further, the control means 8 arbitrarily controls the opening speed of the valve body 5 by the valve body driving means 7 within a time range from the minimum T1 to the maximum T2 shown in FIG. By such an operation, it is possible to suppress the turbulence of the air flow at the time of initial exhaustion and to exhaust the vacuum chamber while preventing the generation of dust.

When the valve body 5 is changed from the open state to the closed state, the valve body 5 may be driven to be closed at a constant speed regardless of the opening speed.

The present invention is not limited to the above-described embodiments, but various modifications can be made within the scope of the invention.

[0015]

As described above, according to the present invention, the exhaust gas conductance changes due to the change of the position of the valve body with respect to the valve seat, and the small exhaust gas conductance in accordance with the initial exhaustion of the valve body to the main exhaust. From the valve element drive means for driving to open so as to have a large exhaust conductance,
By providing the control means for controlling the opening speed of the valve body by the valve body drive means, a vacuum valve capable of performing main exhaust while preventing turbulence of the air flow at the time of initial exhaust is provided. can do.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a vacuum valve that is an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the opening time of the valve body and the opening degree of the valve body in the present embodiment.

[Explanation of symbols]

 1 Vacuum Valve 1A Valve Body 4 Valve Seat 5 Valve Body 7 Valve Body Drive Means 8 Control Means

Claims (1)

[Claims] 1. A valve mechanism in which an exhaust conductance changes according to a change in a position of a valve body with respect to a valve seat, and an opening drive of the valve body from a small exhaust conductance to a large exhaust conductance from initial exhaust to main exhaust. A vacuum valve, comprising: a valve body driving means for controlling the valve body; and a control means for controlling the opening speed of the valve body by the valve body driving means.