Filter candle and mesh pack with a deformable seal, and method of filtering molten or dissolved polymers

1. An elongate mesh pack for filtering a fluid, comprising:

an elongated cylindrical mesh filter medium for filtration of the fluid, an end of which defines an axial opening; and

an end fitting being securely fixed to the filter medium, providing a first extremity of the mesh pack, and having an inner surface defining an end fitting opening through the end fitting, said end fitting opening being co-axial with the axial opening of the mesh pack, the end fitting comprising an annular recess encompassing the end fitting opening, wherein an axially extending partition wall made of a material capable of deforming towards the recess under radial force, is provided between the recess and the end fitting opening, the partition wall defining at least part of the inner surface;

wherein said partition wall deforms against a beveled extremity outer surface of a core tube when such a core tube is slidably moved into said axial opening of the elongate mesh pack, thereby fluidically sealing the end fitting to the core tube.

2. The elongate mesh pack according to claim 1 , wherein the partition wall has a uniform thickness.

3. The elongate mesh pack according to claim 1 , wherein the partition wall has a thickness varying along said axially extending direction.

4. The elongate mesh pack according to claim 3 , wherein the partition wall comprises at least a first annular zone and a second annular zone, the thickness (T p2 ) of the first annular zone being less than the thickness (T p1 ) of the second annular zone.

5. The elongate mesh pack according to claim 1 , wherein the inner surface of the end fitting is substantially cylindrical.

6. The elongate mesh pack according to claim 1 , wherein the inner surface of the end fitting is substantially conical.

7. A filter candle for filtering a fluid, the filter candle comprising:

an elongated cylindrical mesh filter medium for filtration of the fluid, an end of which defines an axial opening;

an end fitting being securely fixed to the filter medium, providing a first extremity of the mesh pack, and having an inner surface defining an end fitting opening through the end fitting, said end fitting opening being co-axial with the axial opening of the mesh pack, the end fitting comprising an annular recess encompassing the end fitting opening, wherein an axially extending partition wall made of a material capable of deforming towards the recess under radial force, is provided between the recess and the end fitting opening, the partition wall defining at least part of the inner surface;

a hollow core tube having a fluid permeable wall and an axial opening, the core tube being removably slidable through the mesh pack axial opening;

the core tube having a first outer extremity having an extremity outer surface having a maximum diameter (D max ), and

the at least part of an inner surface of the end fitting defined by the partition wall having a minimum diameter (D min ) less than the maximum diameter (D max ) of the extremity outer surface;

wherein said partition wall deforms against a beveled extremity outer surface of a core tube when said core tube is slidably moved into said axial opening of the elongate mesh pack, thereby fluidically sealing the end fitting to the core tube.

8. The filter candle according to claim 7 , wherein the core tube has an end flange fixed to the extremity outer surface.

9. A method of filtering comprising the steps of:

providing an elongate mesh pack as recited in claim 1 or a filter candle as recited in claim 7 ; and

passing a molten or dissolved polymer through said mesh pack or said filter candle to remove impurities from said polymer.