Abstract: A sealing port for a filtering device of the type disclosed and claimed in U.S. Pat. No. 3,471,017 is described. The sealing port has two separate sections in uninterrupted communication with one another for sealing purposes but thermally isolated from one another. Both sections are provided with both heating means and coolng means which are controllable to permit the performance of a process sequence wherein a stressed barrier plug (i.e., a sealing plug formed while subject to the hydrostatic pressure of a substance being filtered) is formed in the innermost section (i.e.

Abstract: A process and apparatus for filtering substances by introducing a filter band across a passageway through which the substance flows, the filter being passed through inlet and outlet ports sealed to prevent leakage therefrom for example by thermal solidification therein of the substance being filtered or any other suitable sealing substance to form sealing plugs in the ports, and the filter being advanced to locate a fresh part thereof across the passage by supporting the filter upon a reciprocable backing support, moving the backing support in a direction to advance the filter under conditions such that the filter moves with the backing support, and subsequently retracting the backing support under conditions such as to prevent movement of the filter with the backing support.