Filter element with membrane and bicomponent substrate

A filter element adapted to be located in a gas stream, said filter element comprising:

• a bicomponent substrate having a structure selected from the group consisting essentially of scrimed needled felt, scrimless needled felt, woven fabric and mesh, said substrate comprising at least two different materials, a first one of said materials having a first melting temperature and a second one of said materials having a second melting temperature lower than the first melting temperature;
• an expanded polytetrafluoroethylene filtering membrane adapted to be located upstream relative to said substrate in the gas stream and supported by said substrate;
• and
• an attachment between said substrate and said expanded polytetrafluoroethylene filtering membrane, said attachment comprising said second one of said materials melted to engage said membrane and fix said membrane to said substrate.

A method of making a filter element, said method comprising the steps of:

• providing a substrate having a structure selected from the group consisting essentially of scrimed needled felt, scrimless needled felt, woven fabric and mesh, said substrate comprising at least two different materials, a first one of the materials having a first melting temperature and a second one of the materials having a second melting temperature lower than the first melting temperature;
• providing a filtering membrane;
• supporting the filtering membrane with the substrate;
• and
• attaching the filtering membrane to the substrate by flowing the second one of the materials of the substrate onto the filtering membrane to fix together the filtering membrane and the substrate.