JPS62283263A - Gate valve - Google Patents

Abstract

PURPOSE:To permit a fine conductance control to be performed even in any opening region, by eliminating friction resistance, generated by a packing between a valve and a housing, when the conductance control is performed. CONSTITUTION:When a vacuum valve controls its conductance, first the pressure of oil, applied to an oil pressure introducing port 6, is released. Then a packing 5, which is placed in a condition it is retracted into a housing 3 by the elasticity of the packing itself, comes into no contact with a valve 1. Consequently, the valve 1 can be turned even if no large torque is given to a rotary shaft. While the valve, even when it is completely closed, eliminates the necessity for applying particularly large torque to the rotary shaft. Accordingly, the valve, in whatever opening region it may be, enables a fine conductance control to be performed with no application of torque.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a valve, and more specifically, it is possible to control the opening and closing of a valve in order to adjust the pressure inside a device such as a vacuum device. This invention relates to an exhaust gate valve.

[Prior Art] Among various pressure control systems, exhaust speed control systems using throttle valves are used in many vacuum processes today. This is because throttle valve pressure control has many advantages over Ike's method.

Conventional vacuum valves of this type, which are able to maintain a completely closed state, are constructed by providing an O-ring around the outer periphery of the valve to maintain complete airtightness. In most systems, when controlling the opening and closing of the gate valve and controlling the exhaust speed by changing the valve conductance, the valve is operated at a point close to closed, usually 5 to 50% open. .

However, within this opening range of 30% or less, the frictional force between the O-ring and the valve body becomes large, and the torque applied to the shaft when controlling the opening and closing of the valve becomes large. For this reason, accurate opening/closing control becomes difficult.

In the case of a large vacuum valve of up to 10 inches, this torque can reach a maximum of 40 kQ. This is significantly larger than the torque 2 to 3 when no O-ring is provided, compared to 9-α, and therefore there is a problem that it is not possible to respond to the trend of increasing the diameter of vacuum valves by using an O-ring. Ta.

[Problems to be Solved by the Invention] In view of the problems of the prior art described above, an object of the present invention is to provide a gate valve structure that facilitates control at low opening degrees and can significantly reduce the operating torque of large-diameter valves in particular. Our goal is to provide the following.

[Means for Solving the Problems] The above object is achieved according to the present invention by arranging an elastic packing on the inner wall of the passage along the periphery of the valve when it is near the closed position;
This is achieved by applying an external force to the packing to deform the packing and sealing the periphery of the valve and the inner wall of the passage.

[Operation J] In other words, in the gate valve of the present invention, when the valve is placed in a completely leaping state, the valve is placed in the closed state, and in that state, the packing is suppressed and deformed over the entire circumference of the valve to bring the packing into close contact with the valve. A seal is formed between the peripheral edge and the inner wall of the passage. When the valve is opened to the required opening degree, there is a sufficient gap between the valve periphery and the inner wall of the passage, so that the valve can be rotated easily.

Example 1 Reference is made to the accompanying drawings, which illustrate embodiments of the invention.

1 is a valve that rotates to control conductance, 2 is a rotating shaft that rotates valve 1, 3 is a housing, 4 is an O-ring for sealing with the outside, 5 is a packing attached to the inner wall of the passage, 6
is an inlet for pressurized fluid for pressing the packing 5 against the valve 1.

Explain the operation. When the vacuum valve controls its conductance, it first releases the hydraulic pressure applied to the hydraulic inlet 6.

The packing 5 is then retracted into the housing 3 with its own bullet saw (FIG. 3) and no longer contacts the valve 1. Therefore, the valve 1 can be rotated without applying a large torque to the rotating shaft 2. Further, when the valve is to be completely closed, the rotary shaft 2 is first driven to set the valve 1 to the closed position, and then hydraulic pressure is applied to the hydraulic pressure inlet 6. Then, the packing 5, which had been separated from the valve 1, is pushed out from the housing 3 by the hydraulic pressure and comes into close contact with the periphery of the valve 1, sealing the gap between the valve and the inner wall of the passage (FIG. 2). In this way, even when the valve is completely closed, a particularly large torque is applied to the rotating shaft 2.
There is no need to apply it.

Although flat packing is used in this embodiment, a hollow tubular O-ring may be used to apply hydraulic pressure within the duplex. Further, a mechanism using a cam or the like may be used instead of the hydraulic mechanism.

[Effect of light] As is clear from the above, according to the present invention, there is no frictional resistance due to packing between the valve and the housing during conductance control, so minute conductance control can be performed in any opening range. In addition, even large-diameter valves do not require a large driving torque, so they are easy to operate.

Furthermore, since the packing does not rub during valve operation, there is less wear and tear on the packing, eliminating the risk of gas leaks.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the gate valve of the present invention. FIG. 2 is a sectional view taken along line 8--0 in FIG. 1. FIG. 3 is a sectional view taken along line A'--○ in FIG. 1. In the figure, 1: valve, 2: rotating shaft, 3: housing, 4: 0 ring,
5: Packing, 6: Hydraulic pressure inlet.

Claims (1)

[Claims] 1. Housing having a valve passage; Continuously rotates between a closed position perpendicular to the valve passage and closing it, and an open position parallel to the valve passage and opening it. a resilient packing disposed on the inner wall of the passage around the periphery of the valve when near the closed position and pressed sealingly around the valve in response to an external force; A gate valve characterized by being equipped with an external force applying means for applying an external force to the packing. 2. The gate valve according to claim 1, wherein the external force applying means includes a passage penetrating the peripheral wall of the housing, and means for applying hydraulic pressure to the packing via the passage. 3. The gate valve according to claim 2, wherein the packing is a flat packing. 4. The gate valve according to claim 2, wherein the packing is a hollow tubular O-ring. 5. The gate valve according to claim 1, wherein the external force applying means is a cam mechanism.