Abstract: The specification discloses a filter apparatus including spirally wound tissue layer filter elements for filtering fluid and a seal between the filter elements to prevent fluid from bypassing the filter elements. A flow tube extends through the center of the filter elements. A resiliently deformable mesh spacer is located on the flow tube between the filter elements to insure formation of a radial passageway therebetween. The seal is applied between the filter elements along their circumferential edges in a melted state and migrates into and between the tissue layers and interstices of the filter elements and the mesh of the spacer. As the seal cools and hardens it adheres to the filter elements and the spacer. A seal may likewise be applied between the filter elements and the flow tube.