For rigidity increasing of panel type air filters there are used especially made glue lines, metal or plastic nettings.

They add rigidity to construction, especially in large capacity engines or turbo en­gines where the requirement for air is relatively high.

In this case the filtering element is exposed to strong pressure (applied forces are trying to push filter inside engine).

It is quite dangerous effect in the final stage of filters exploitation, when gathered contaminations bridge pores of the filter partition and cause sufficient air flow resistance.

The characteristic symp­toms of this effect will be the increased fuel consumption and noticeable engine power loss.

That is why it is necessary to watch over the periodicity of filters replacement depending on exploitation conditions and not just run kilometers.