초록 ▼

A filter vial and piston are provided where the vial has a cylindrical wall with a closed bottom and open top and with the hollow, tubular piston therein. The piston has a distal end covered by a cup having a proximal cup seal extending outward to engage the walls of the vial to form a fluid tight s

A filter vial and piston are provided where the vial has a cylindrical wall with a closed bottom and open top and with the hollow, tubular piston therein. The piston has a distal end covered by a cup having a proximal cup seal extending outward to engage the walls of the vial to form a fluid tight seal with the vial during use. The distal end of the piston has a piston flange extending outwardly and located adjacent a recess in the piston so the cup forms a snap fit over the piston flange and extends into the recess. The piston flange causes the cup to bulge sufficiently outward to form a fluid tight seal with the vial during use. A filter is placed in the bottom of the cup.

대표청구항 ▼

What is claimed is: 1. A filter vial apparatus having a longitudinal axis, comprising: a tubular vial having a closed bottom, an open top and walls defining a cylindrical interior with a diameter D; a tubular piston with opposing distal and proximal ends with at least the distal end being open, the

What is claimed is: 1. A filter vial apparatus having a longitudinal axis, comprising: a tubular vial having a closed bottom, an open top and walls defining a cylindrical interior with a diameter D; a tubular piston with opposing distal and proximal ends with at least the distal end being open, the piston having walls defining a cylindrical interior with an exterior facing recessed portion adjacent the distal end the piston, the piston further having a distal piston flange at or adjacent to the distal end of the piston and extending outward from the piston; a filter support located inside the piston at the distal end of the piston; a retainer cup having a continuous sidewall extending between a proximal and distal end of the cup with an interior diameter smaller than the distal piston flange and having a lip extending inward toward the longitudinal axis at the distal end of the retainer cup, the retainer cup further having a cup seal extending outward from the proximal end of the cup a distance greater than the diameter D, the sidewall of the cup being sufficiently flexible to deform outward as the cup passes over the distal piston flange to assume an outer dimension larger than diameter D at the location of the piston flange when the retainer cup passes over the distal piston flange; and a filter interposed between the retaining cup's lip and the distal end of the piston when the proximal end of the retainer cup is placed over the distal end of the piston. 2. The apparatus of claim 1, wherein the piston and retainer cup are placed through the open end of the filter vial so the retainer cup abuts and forms a fluid seal with the inside of the vial at the location of the cup seal and at the location of the distal piston flange. 3. The apparatus of claim 1, wherein the distal end of the piston has a distal edge with a rib on that distal edge, the rib extending around a circumference of the piston and being oriented to abut the filter during use so as to press the filter against the lip of the cup during use. 4. The apparatus of claim 1, wherein the lip extends continuously around an inner circumference of the retainer cup and the recessed area extends entirely around a circumference of the piston. 5. The apparatus of claim 1, wherein the piston, vial and retaining cup are made of a polymer. 6. The apparatus of claim 1, further comprising a cap sized to releasably but snugly fit over the proximal end of the piston. 7. The apparatus of claim 2, wherein the cup seal on the proximal end of the cup abuts an end of the recess in the piston. 8. The apparatus of claim 2, further comprising a seal extending outward from the piston adjacent the proximal end of the piston and located to engage and form a fluid tight seal against the vial when the distal end of the piston is adjacent the bottom of the vial. 9. The apparatus of claim 1, wherein the piston flange has a generally triangular cross sectional shape which is larger at the proximal end and smaller at the distal end of the seal. 10. A filter vial assembly, comprising: a cylindrical walled vial with a closed bottom and open top having a hollow, tubular piston therein, the piston having a distal end covered by a cup having a proximal cup seal engaging the walls of the vial to form a fluid tight seal when the piston is advanced into the vial a distance sufficient to engage the proximal cup seal with the vial walls, the distal end of the piston having a piston flange extending outwardly and located adjacent a recess in the piston so the cup forms a snap fit over the piston flange and extends into the recess, the piston flange causing flexible walls of the cup to bulge sufficiently outward to form a distal fluid tight cup seal with the vial when the flange and cup are inserted into the vial; and a filter having a periphery abutting an inwardly extending lip on the cup and held between a piston support at the distal end of the piston and the lip. 11. The filter vial assembly of claim 10, further comprising a cup support at a distal end of the cup abutting the filter. 12. The filter vial assembly of claim 10, further comprising an outwardly extending seal adjacent a proximal end of the piston sized and configured to form a fluid tight seal when engaged with the cylindrical walls of the vial. 13. The filter vial assembly of claim 11, wherein the distal end of the piston has a distal edge with a rib extending therefrom and oriented to press the filter against the lip of the cup. 14. The filter vial assembly of claim 10, further comprising a removable cap covering the proximal end of the piston. 15. The filter vial assembly of claim 12, further comprising a vent hole extending through a wall of the piston and located adjacent the seal adjacent the proximal end of the piston and distal of that piston flange. 16. A method of forming a piston for a filter vial, the piston having a cylindrical tube with opposing proximal and distal ends, comprising: forming an outwardly extending piston flange at the distal end of the piston; forming a cylindrical recess around a periphery of the distal end of the piston at the distal end of the piston and adjacent to the piston flange and on the proximal side of the piston flange; placing a filter in the bottom of a retaining cup which cup is sized to fit over the distal end of the piston, the retaining cup having an open proximal end and an inward extending lip at an opposing distal end which lip abuts a periphery of the filter; placing the open proximal end of the cup over the distal end of the piston and piston flange to form a snap fit between the proximal end of the cup and the recess on the piston and advancing the retaining cup along the piston until the distal end of the piston abuts the filter, the retaining cup having an outwardly extending seal at the proximal end sized to sealingly engage the inside of the filter vial during use, the retaining cup being made of sufficiently flexible material to bulge outward at the piston flange with the piston flange and retaining cup being dimensioned to extend outward a distance sufficient to form a fluid tight seal with walls of the filter vial during use. 17. The method of claim 16, further comprising providing a filter support on the distal end of the retaining cup, the filter support located to abut the filter during use. 18. The method of claim 16, further comprising providing a piston filter support on the distal end of the piston, the piston filter support located to abut the filter during use. 19. The method of claim 17, further comprising providing a piston filter support on the distal end of the piston, the piston filter support located to abut the filter during use. 20. The method of claim 17, further comprising a rib on a distal edge of the piston located to form an axial facing seal around a periphery of the filter. 21. A filter vial apparatus having a longitudinal axis, comprising: a tubular vial having a closed bottom, an open top and walls defining a cylindrical interior with a diameter D extending between the top and bottom; a tubular piston with opposing distal and proximal ends with at least the distal end being open, the piston having walls defining a cylindrical interior, the piston further having a distal piston flange at the distal end of the piston and extending outward from the piston; a filter support located inside the piston at the distal end of the piston; a retainer cup having a cylindrical sidewall extending between a proximal end and distal end of the cup, the cup having an interior diameter smaller than the distal piston flange, the sidewall of the cup being sufficiently flexible to deform outward as the cup passes over the distal piston flange to assume an outer dimension larger than diameter D at the location of the piston flange when the retainer cup passes over the distal piston flange, the retainer cup further having a cup seal extending outward from the proximal end of the cup a distance sufficient to seal against the vial wall when the distal piston flange is inserted into the cup and causes said outward deformation of the cup sidewall, the cup having an opening in the distal end; and a filter covering the opening in the distal end of the cup. 22. The apparatus of claim 21, wherein the piston further has an exterior facing recessed portion adjacent the distal end the piston, with the proximal end of the cup being placed in that recessed portion during use of the assembly. 23. A filter vial assembly, comprising: a cylindrical walled vial with a closed bottom and open top having an inner diameter D between its top and bottom, the vial having a hollow, tubular piston therein, the piston having a distal end covered by a cup having a proximal cup seal engaging the walls of the vial to form a fluid tight seal when the piston is advanced into the vial a distance sufficient to engage the proximal cup seal with the vial walls, the distal end of the piston having a piston flange extending outwardly and causing the flexible walls of the cup to bulge sufficiently outward to form a distal fluid tight seal with the vial when the flange and cup are inserted into the vial; and a filter in a distal end of the cup located to cover an opening in the distal end of the cup through which fluid flows during use of the assembly. 24. The assembly of claim 23, wherein piston flange is located adjacent a recess in the piston so the cup forms a snap fit over the piston flange and extends into the recess during use of the assembly. 25. A method of forming a piston for a filter vial, the piston having a cylindrical tube with opposing proximal and distal ends, comprising: forming an outwardly extending piston flange at the distal end of the piston; forming a cylindrical recess around a periphery of the distal end of the piston at the distal end of the piston and adjacent to the piston flange and on the proximal side of the piston flange; placing a filter in the bottom of a retaining cup which cup is sized to fit over the distal end of the piston, the retaining cup having an open proximal end and an opposing distal end with an opening in the distal end, the filter covering the opening; placing the open proximal end of the cup over the distal end of the piston and piston flange to form a snap fit between the proximal end of the cup and the recess on the piston and advancing the retaining cup along the piston until the distal end of the piston abuts the filter, the retaining cup having an outwardly extending seal at the proximal end sized to sealingly engage the inside of the filter vial during use, the retaining cup having a sufficiently flexible side so that the side bulges outward at the location of the piston flange with the piston flange and retaining cup being dimensioned so the cup side bulges outward a distance sufficient to form a fluid tight seal with walls of the filter vial at the location of the piston flange during use. 26. A piston for a filter vial, the piston having a cylindrical tube with opposing proximal and distal ends, comprising: an outwardly extending piston flange at the distal end of the piston; a cylindrical recess around a periphery of the distal end of the piston at the distal end of the piston and adjacent to the piston flange and on the proximal side of the piston flange; a retaining cup having an open proximal end which is sized to fit over the distal end of the piston, the retaining cup having a distal end opposite the proximal end with an opening in the distal end, and a continuous side extending between the proximal and distal ends of the cup, the open proximal end of the cup extending over and past the distal end of the piston and piston flange to form a snap fit between the proximal end of the cup and the recess on the piston, the retaining cup having an outwardly extending cup seal at the proximal end, the cup seal being sized to sealingly engage the inside of the filter vial during use, the side of the retaining cup being sufficiently flexible so that the side bulges outward at the location of the piston flange with the piston flange and retaining cup being dimensioned so the cup side bulges outward a distance sufficient to form a fluid tight seal with walls of the filter vial during use. 27. The piston of claim 26, wherein the distal end of the piston and the distal end of the cup each abut the filter.