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An Effective Way To Increase The Shielding In The Chassis Cabinet
- Jan 05, 2018 -

The biggest problem is the chassis cabinet heat dissipation in the summer, for the chassis cabinet cooling start vent is the designer of the common cooling method. Ventilation of the screen is to meet the ventilation requirements of the chassis interior, and sometimes must be opened in the ventilation holes on the box. Therefore, the ventilation holes must also be electromagnetically shielded. The ways in which such situations increase the shielding effectiveness are as follows:

(1) Covering the metal mesh on the window of the chassis cabinet: There are two types of metal mesh covering the ventilation holes, one is welding, and the method is good between the metal mesh and the shield Of the electrical contact, but the process is complex, difficult to replace the performance of the metal mesh after the change, and easy to damage the surrounding protective layer when welding, so rarely used this method. Another is the use of ring pressure ring by tightening the screw to the metal mesh installed in the shield of the ventilation holes. Before installation, the mating surface should be insulating, oxide, grease and other non-conductive material removed, and should be installed a sufficient number of screws to obtain continuous contact. This installation, as long as the chassis cabinet structure and process carefully considered, you can make the metal mesh and the shield to obtain good electrical contact, so the application is more extensive. The company is located in:

(2) with perforated metal plate for ventilation holes: The use of many small holes instead of large-diameter ventilation holes is an effective way to improve the shielding effectiveness, which can open many holes directly in the shield, can also be made of perforated metal plate installed alone To the shield of the vents. Compared with metal mesh, perforated metal plate is characterized by the performance of the shield is stable, because it does not exist at the metal mesh woven mesh inherent contact resistance instability. In the shielding wall directly open a small diameter vents, with the advantages of simple structure and process, low cost, the actual application in the chassis cabinet industry has been more common. The company is located in:

(3) the use of cut-off waveguide ventilation window: metal mesh and perforated metal plate at higher frequencies, the shielding effectiveness should decline, especially when the hole size and electromagnetic wavelength comparable, the eyelet will cause serious leakage. At higher frequencies, for high shielding and well-ventilated, cut-off waveguide vented plates (such as honeycomb vents) can be used which have the following advantages over wire mesh and perforated plates: Work Of the band wide, even to the microwave band still has a higher shielding performance; resistance to air, wind pressure loss less; high mechanical strength, reliable and stable work.