Wednesday, April 3, 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.

Determine their capacity to withstand heat. Applications that lead to the production of heat require seals that accommodate the temperatures. Therefore, you need to acknowledge the maximum heat produced by the device to determine the best material that can withstand it. Most metallic metals have quite a lot of conduction; hence you should choose a design that releases the heat to the environment.

Factor in the potential to accommodate pressure. Applications that require pressure or form pressure need a seal that can withstand it. As the applied pressure increases, the variety of materials that can accommodate it narrows. The supplier should advise you about the maximum pressure that a particular seal can withstand before you decide on one. You should also beware of the maximum force exerted by your device to choose the right material.

Consider at which stage of manufacture you would consider making of the gasket. If you want a custom-made gasket, you have to consider it at its design stage. Trying to fit a seal on a flange that does not match with its design can make the whole device unreliable. While choosing the model, ensure that there is enough land that can offer different mounting options. Some of the mounting methods that one can select include slot, clip-on, pressure sensitive adhesive and channel mounting.

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.

Confirm whether the seals are compatible with the enclosed material. Galvanization corrosion can happen when there are salt spray and the metal used in the seal, and the enclosed one has different noble states. So, one should use metals that have more or less close galvanization scale to avoid such occurrence. One of the commonly used combinations includes coated silicone elastomer to cover a coated nickel product.

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.

Learn how to maintain the seals. The gaskets tend to wear out with time. Therefore, one has to acknowledge various ways to preserve the longevity of these products. The right way includes regular maintenance and using compression collars and stops. The compression collars are quite useful since they reduce breaking in case of too much pressure.




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