Filter vial

A filter vial apparatus having a longitudinal axis, comprising:

• a cylindrical walled vial with a closed bottom and an open top, the vial having a centrally located protrusion on the bottom that extends toward the top to form an annular recess at the bottom of the vial;
• a hollow, tubular plunger extending into the vial, the plunger having an annular bottom with an axially facing recess therein ending at an annular wall encircling and defining a recess opening in fluid communication with a cavity inside of the tubular plunger;
• an annular cap having inner and outer sidewalls placed over the annular bottom of the plunger with the outer sidewall on an outer sidewall of the plunger, the outer sidewall has an outer surface a first portion of which extends outward from the longitudinal axis a distance sufficient to form a first sealing surface that forms a fluid tight seal with the cylindrical wall of the vial when the plunger is advanced into the vial a distance sufficient to engage the first portion with the vial's wall during use of the assembly, the inner sidewall of the cap fitting into the axially facing recess and extending a distance sufficient to hold a filter against the annular wall of the recess and to place the filter in fluid communication with the shaped cavity formed by the inner sidewall of the annular cap, the annular cap being configured to fit into the annular recess of the vial with the vial's protrusion snuggly fitting into the shaped cavity.

A tubular plunger assembly for filtering fluids, comprising:

• a tubular plunger having at least an open bottom with a fluid holding cavity in the plunger, the plunger having a bottom end with an inner and an outer annular surface which encircle and are orthogonal to a longitudinal axis of the plunger and are separated a distance along that by a recess sidewall that encircles and faces the longitudinal axis to define a plunger recess in the bottom end of the plunger, the inner annular surface encircling and defining an opening to the recess which opening is in fluid communication with the fluid holding cavity of the plunger;
• an annular cap having an annular cap bottom from which extend inner and outer sidewalls configured to fit over the bottom end of the plunger, the outer sidewall fitting over an outer surface of the bottom end of the plunger, the inner and outer sidewalls receiving the outer annular surface therebetween, the inner sidewall having an outer surface abutting the sidewall of the plunger recess, the inner surface of the inner sidewall defining a shaped cavity in fluid communication with the opening to the recess, the inner sidewall having a top end;
• and
• a filter located the top end of the inner sidewall and the inner annular surface;
• wherein a portion of the outer surface of the outer sidewall of the annular cap, at or by the bottom of the annular cap, extends outwardly a distance sufficient to form a first sealing surface that provides a fluid tight seal against a filter vial when the cap is inserted into the vial during use of the plunger assembly.

A filter vial kit, comprising:

• a hollow tubular plunger having top and bottom ends with an opening at a bottom end of the plunger;
• a filter extending across the opening in the bottom end of the plunger;
• an annular cap fastened to the bottom end of the plunger, an outer sidewall of the cap extending along an outer surface of the bottom end of the plunger with a portion of that outer sidewall extending outward a predetermined distance to form a first sealing surface, the annular cap having an inner sidewall forming a shaped cavity in fluid communication with the opening in the bottom end of the plunger;
• and
• a vial having an open top and a closed bottom having a central protrusion extending toward the open top of the vial, the vial having a sidewall that is sufficiently smaller in cross-section than the predetermined distance to form a fluid tight seal between the vial and annular cap, the bottom of the annular cap and the shaped recess being configured to mate with the shape of the a vial's bottom and the protrusion so as to force fluid in the vial through the shaped cavity and filter.

A filter vial and plunger assembly for filtering fluids, comprising:

• a tubular plunger having sidewalls defining an internal fluid cavity and having a top and bottom ends with a plunger opening in the bottom end of the plunger;
• an annular cap connected to the bottom end of the plunger, the annular cap having concentric inner and outer sidewalls with the outer sidewall connected to an outer sidewall of the plunger and the inner sidewall defining a shaped cavity in fluid communication with the plunger opening, the cap's outer sidewall having an outwardly extending first sealing surface at or by its bottom;
• a filter interposed between the cap's inner sidewall and the plunger opening;
• a vial having an open top and closed bottom joined by cylindrical sidewalls of sufficient diameter to form a fluid tight seal with the first sealing surface, the vial having a protrusion extending from the center of its bottom toward the top, the bottom of the annular cap and the bottom of the vial having complementary shapes, including complementary shapes of the protrusion and shaped cavity, to direct fluid from the vial through the shaped cavity during use.