Saturday, March 23, 2019

Tips For Buying EMI Seals

By Donald Green


Electric induction and coupling can cause electromagnetic interference. Therefore, a lot of equipment that has such electrical functions should have a gasket to avoid affecting critical applications such as aerospace electronics, military, medical and vehicular systems. Anyone who intends to buy such a seal should consider a few aspects. The following are guidelines for buying EMI seals to consider.

Ensure that it can withstand high temperatures. You have to confirm whether the gasket can accommodate high temperatures if the device it is shielding generates a lot of temperatures. Therefore, you have to choose a material that can withstand the respective heat. You have to acknowledge the maximum temperature provided by the maker to make a reasonable choice.

Ensure that it can accommodate pressure. Some applications lead to tension. Such phenomenon requires a reliable gasket that can withstand it. There are varieties of materials that one can use depending on the amount of pressure induced. The best types of seals include the wire mesh types and the copper fingers which release force to the environment.

Confirm when to design the seal. Custom-made gaskets have high chances of offering the appropriate service. Even so, you should acknowledge the best manufacture stage to design and manufacture the seal to get the best result. The best step is the designing phase where the manufacturer can leave enough flange to fix the gasket. It also provides flexibility in the choice of mounting to use.

Consider a gasket that protects the device from dust and moisture. Dust and humidity are common in most applications. For that reason, one should look for a seal that can deal with these elements accordingly. The best choice includes the rubber sealing or a conductive elastomer which are ideal for moisture and dust. Another material to use is the conductive fabric which protects the device from dust.

Take note of material compatibility. When two metals come into contact, there are chances of having galvanic corrosion if there is the presence of galvanic corrosion and salt spray. Therefore, it is recommendable to choose metals that has a different galvanic scale compared with the metal that one intends to enclose. One of the typical examples includes using a nickel coated enclosure to contact a coated graphite in a silicone elastomer seal.

Determine which frequencies you want to shield. Most aerospace and military applications require a shield that can inhibit magnetic waves. Therefore, using a knitted wire mesh or copper fingers can be a perfect match to release the induced current within the guard. For low frequencies, one should use a solid metal while electric can fit in any gasket to their limitation.

Acquaint with the maintenance process. Ensure that the gasket that you decide on has a mechanism to open and close it when you want to do any maintenance. Make sure that you clean it periodically and replace it when it has worn out completely. You should also use a compression stop or collar to avoid breaking when the gasket stays for too long without maintenance.




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