Filter assemblies and methods for producing filter assemblies

A method of making a filter cap comprising the step of:

• die stamping a composite sheet to form the filter cap wherein the composite sheet comprises:
• a sheet metal layer having a planar surface;
• and a heat liquefiable adhesive that is adhered to the planar surface of the sheet metal layer and is solid at room temperature;
• and
• wherein the filter cap formed by the die stamping step has a base section with a filter facing surface and an outer facing surface and at least one upwardly extending perimeter wall having a filter facing surface and an exterior facing surface wherein the at least one upwardly extending perimeter wall extends upwardly from the base section and wherein the perimeter wall defines the base section of the filter cap and wherein the filter facing surface of the base section and the filter facing surface of the upwardly extending perimeter wall each comprises the heat liquefiable adhesive in solid form before and after the die stamping step.

A method of making a filter assembly comprising the steps of:

• forming a first composite sheet comprising a metal layer having a planar surface and a surface layer on the planar surface comprising a heat liquefiable adhesive in solid form wherein the heat liquefiable adhesive adheres to the planar surface of the metal layer in solid form at room temperature;
• stamping the first composite sheet while the heat liquefiable adhesive is in solid form to form a first filter cap having a base section with a filter facing surface and an outer facing surface and at least one upwardly extending perimeter wall having a filter facing surface and an exterior facing surface wherein the at least one upwardly extending perimeter wall extends upwardly from the base section and wherein the filter facing surface of the base section and the filter facing surface of the at least one upwardly extending perimeter wall each have the heat liquefiable adhesive on a surface thereof;
• placing a filter material into contact with the heat liquefiable adhesive in physical contact with the filter facing surface of the base section and the filter facing surface of the at least one upwardly extending perimeter wall while the heat liquefiable adhesive is in solid form;
• applying heat to at least a portion of the heat liquefiable adhesive of the first filter cap at a temperature sufficient to liquefy at least a portion of the heat liquefiable adhesive of the first filter cap and cause the heat liquefiable adhesive of the first filter cap to adhere to the filter material along the filter facing surface of the at least one upwardly extending perimeter wall for a height of the at least one upwardly extending perimeter wall and on the base section of the first filter cap;
• placing a second filter cap having a base section with a filter facing surface and an outer facing surface and at least one upwardly extending perimeter wall having a filter facing surface and an exterior facing surface wherein the at least one upwardly extending perimeter wall extends upwardly from the base section and wherein the filter facing surface of the base section and the filter facing surface of the at least one upwardly extending perimeter wall each have the heat liquefiable adhesive on the surface thereof in solid form;
• and
• applying heat to at least a portion of the heat liquefiable adhesive of the second filter cap at a temperature sufficient to liquefy at least a portion of the heat liquefiable adhesive of the second filter cap and cause the heat liquefiable adhesive of the second filter cap to adhere to the filter material along the filter facing surface of the at least one upwardly extending perimeter wall for the height of the filter facing surface of at least one upwardly extending perimeter wall and on the base section of the second filter cap.