DD244797A1 - DEVICE FOR VENTILATION OF VACUUM CHAMBERS - Google Patents

Abstract

Device for ventilating vacuum chambers, in particular for electron beam machining systems, characterized in that at least two valve-connected, cascading-structured and except a smallest valve openings provided with Ventiloeffnungen is located directly on a Belueftungsoeffnung the vacuum chamber and is provided for sealing the same and the Luftdurchtrittsflaeche the Ventiloeffnungen increases from the smallest to the largest valve plate that a Stoessel arranged centric to the valve plates and the smallest valve plate with the bump is firmly connected and that between the valve plates each one mechanically connected to the bumper driver is arranged. Fig. 1

Description

For this 1 page drawings

Field of application of the invention

The invention relates to a device for ventilating vacuum chambers, in particular for electron beam machining systems.

Characteristic of the known technical solutions

All known vacuum vent valves open the flood opening to the full size when the input signal is applied.

This process usually takes place in a time t <1 see. The opening cross-section determines the ventilation time of vacuum chambers.

In this case, an optimization of the opening cross section with respect to the ventilation time must be made.

If a valve with a large opening cross-section is selected for a vacuum system, the resulting turbulence can lead to destruction or changes to the structures in the vacuum system.

But if a valve with a smaller opening cross-section is used, the aeration time increases and the productivity of the system is reduced.

Object of the invention

The aim of the invention is to eliminate the disadvantages indicated in the known technical solutions.

Explanation of the essence of the invention.

The object of the invention is to develop a device for ventilation of vacuum chambers, with which a vacuum chamber can be vented in the shortest possible time with low turbulence within the vacuum chamber. The object is achieved with a device according to the preamble of claim 1 according to the invention by the features of the characterizing part of the main claim. Preferred developments are described in the subclaims. According to the invention, a valve cascade is opened during ventilation with a constant force. This force acts on the plunger and is chosen so that the smallest valve disc of the cascade open, but the next larger valve disc can not be raised because of the large pressure difference. With decreasing pressure difference, the force on the plunger is sufficient to lift over the first driver the next valve plate and thus increase the air passage area (ventilation cross-section). This process is repeated until the last (largest) valve disk or until complete compensation of the pressure difference.

Thus, the solution according to the invention ensures rapid ventilation with low turbulences in the vacuum chamber by changing the ventilation cross section.

embodiment

The invention is explained below with reference to the drawings

 Show it:

Fig. 1: Construction of the ventilation device

Fig. 2: graphical representation of the ventilation curve in the prior art and the inventive solution

With the beginning of the ventilation, the force F is applied to the valve lifter 1. The force F is chosen so large that it is just able to lift the smallest valve plate and thus initiate the ventilation.

With decreasing pressure difference Δρ = pu, "- Pvakuum and constantly applied force F, the next larger valve disk 3 is raised by the driver 5.

However, the pressure difference Δρ is so high that the force F is insufficient to lift the next larger vacuum plate 4.

After further decrease in the pressure difference .DELTA.ρ the vacuum plate 4 is raised by the driver 6.

-2- ^ t ** / Z) J

The valve disk 2 is vacuum-tight with the valve lifter 1 and the drivers 5 and 6 are mechanically fixed (eg shaft securing rings, snap rings or the like) to the valve lifter 1.

In the valve plates 3 and 4 valve openings 7 are provided, which are decisive for the flow velocity in the ventilation process. These vent openings 7 may increase in size or number as the valve disk size increases. The sealing rings 8 are located between the valve plates 2, 3, 4 and between the valve plate 4 and the housing 9. The number of valve plates depends on the specific application, the force F and the size or number of valve openings 7.

Claims (2)

claims: 1. A device for ventilating vacuum chambers, in particular for electron beam machining plants, characterized in that at least two, are interconnected by seals, cascading constructed and provided with a valve openings except a smallest valve plate, wherein the largest valve plate is located directly on a ventilation opening of the vacuum chamber and is provided for sealing the same and the air passage area of the valve openings increases from the smallest to the largest valve plate, that a plunger centric to the valve plates arranged and the smallest valve plate with the plunger is firmly connected and that between the valve plates each one mechanically connected to the plunger driver is arranged , 2. Device according to claim 1, characterized in that the plunger is cylindrical and arranged perpendicular to the ventilation opening of the vacuum chamber and that the drivers are snap rings.