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Shanghai Gaochuan Valve Manufacturing Co., Ltd.

Address: No. 2465, Hengcang Road, Malu Town, Jiading District, Shanghai

Phone 1: 021-56772777 

Phone 2: 021-56521514 

Phone 3:021-56521504

Fax: 021-56770777

QQ: 49453698

E-MAIL: gcvalve@126.com


Common types of metal sealing flanges for vacuum pipe fittings

2021-04-20 01:42:37

In some very high vacuum equipment that requires high temperature baking (a baking environment greater than 200ºC) or low vapor pressure ( vacuum equipment less than 10°C at room temperature ), metal sealing materials are not resistant to high temperatures and have a large amount of outgassing. , Not suitable for use in this environment.

There are the following types of metal sealing flanges :

1. Aluminum foil sealing.

When the outer seal is compressed with 30% compression, the middle aluminum foil can be sealed so that its two ends are under a relatively high pressure state, so as to achieve the sealing effect. Due to the processing of the deflection angle, the bolt will have an excessively large angle.

In general, the locking torque of the aluminum foil seal is 40N•m-50N•m. When the surface roughness value of the seal is 0.5μm-4.4μm, and the thickness of the seal is 40μm-100μm, the aluminum foil seal can withstand repeated baking at high temperature of 250μC-350μC. If the locking torque is 45N•m and the baking temperature is higher than 300ºC, pad the aluminum foil on the sealing surface. The result will be a better vacuum sealing effect, but the molten aluminum foil should be removed during the next use.

2. Step seal.

The seal formed by cutting the fresh metal surface with two right-angle shearing forces is called a step seal. The two right-angled shear forms of this process are interval and overlap. Use oxygen-free high-conductivity copper as the gasket with a thickness of 1mm-3mm. During manufacturing, it can be annealed in a 950ºC hydrogen-burning furnace, and it can also be repeatedly baked under a high temperature environment of 450ºC. The tolerance of the two right angles is large, no need to consider the matching problem, and the processing is simple.

3. Oblique wedge seal.

The oblique wedge seal has 70 knife edge angles, 0.1mm knife tip fillet radius, 0.075mm-0.1mm depth tolerance, 1mm-1.5mm height, 0.05mm knife edge diameter error, sealing material is 6mm width, 2-3mm thickness anaerobic High conductivity copper. In a high temperature environment of 250ºC, a vacuum equipment with a wedge-sealed structure can make the equipment reach 2.6x10Pa under vacuum pressure within 5 hours of baking time.

4. The knife edge is sealed.

The sealing ring of the cutter is a 0.5mm annular aluminum sheet or copper sheet, the sealing force can reach 280MPa, the baking temperature can reach 450ºC, and it can withstand repeated heating and cooling cycles without air leakage. However, the requirements for fitting accuracy are relatively high, and are generally used in small-size flange seals.




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 Address: No. 2465, Hengcang Road, Malu Town, Jiading District, Shanghai

Phone: 021-56772777 56521514 56521504

 Fax:021-56770777          QQ:49453698