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US 8,728,329 B2Granted
Method for filtering fluid using a filter vial
AssigneeScientific Plastic Products, Inc.
InventorsSamuel A. Ellis, Kishan G. Hingorani
Life of this patent
Estimating the term…
Abstract
A method filters particles from small volumes of fluid in a tubular vial having an open top and closed bottom with a tubular plunger sliding in the vial to force fluid through a filter at the end of the plunger and into a cavity in the plunger. The filter is held by a cap placed over the end of the plunger. The vial's bottom has an upward extending protrusion mating with a conforming recess in the cap to direct fluid to the protraction and filter as the cap abuts the bottom of the vial. Channels in the bottom help direct fluid flow.
Claims35
A method of filtering particles from small volumes of biological or chemical fluids, comprising:
- providing a tubular vial having a closed bottom, an open top and a sidewall defining a cylindrical interior with a diameter D located along a longitudinal axis of the vial, the closed bottom having a protrusion extending toward the open top, the vial bottom and protrusion defining an annular recess about the vial's longitudinal axis of the vial with the protrusion at the center of the annular recess;
- providing a tubular plunger assembly having a longitudinal axis, the plunger having opposing top and bottom ends joined by a sidewall to define an fluid holding cavity in the plunger, the bottom end having an outer annular surface and an inner annular surface axially offset toward the top end from the outer annular surface, the inner annular surface being generally orthogonal to the longitudinal axis and joined to the first annular surface by a recess sidewall to form a recess that encircles the longitudinal axis, the second annular surface defining a recess opening that is in fluid communication with the fluid holding cavity of the plunger, the bottom end of the plunger having an annular cap fit over that bottom end, the cap having inner and outer concentric sidewalls defining an annular recess into which the outer annular surface on the bottom of the plunger has been placed, the cap's outer sidewall extending over the outer surface of the bottom of the plunger and the cap's inner sidewall being placed adjacent the sidewall of the recess in the end of the plunger, the inner sidewall of the cap defining a shaped cavity configured to snugly receive the protrusion on the vial's bottom, the shaped cavity having an upper end in fluid communication with the recess opening, a filter being interposed between the inner annular surface in the plunger and the inner wall of the annular cap;
- placing fluid into the vial;
- inserting the annular cap into the open top of the vial, an outer surface of the outer sidewall of the cap having a diameter sufficiently larger than diameter D of the vial to form a fluid tight seal when the plunger assembly is advanced into the vial and toward the vial bottom;
- and
- advancing one of the cap and the bottom of the vial toward the other to force the fluid through the filter and into the cavity in the plunger.
3 more elements
A method of filtering fluid using a vial having a longitudinal axis, comprising:
- providing 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;
- providing a hollow, tubular plunger and extending the plunger into the vial with fluid located between the bottom of the vial and the plunger, 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, the plunger having an annular cap over a bottom of the plunger, the annular cap having inner and outer sidewalls so an outer sidewall of the cap is on an outer sidewall of the plunger, the outer sidewall of the cap having 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 as the plunger is advanced into the vial a distance sufficient to engage the first portion with the vial's wall, the inner sidewall of the cap fitting over the end of the plunger 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;
- advancing the tubular plunger toward the bottom of the vial until fluid passes through the filter and into the cavity inside the tubular plunger.
A method for filtering fluids with a vial and plunger assembly, comprising:
- providing 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;
- providing 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, the cap being placed on the bottom end of the plunger with a filter interposed between the cap's inner sidewall and the plunger opening;
- providing 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;
- placing fluid in the vial;
- placing the annular cap in the vial and advancing at least one of the cap and vial bottom toward each other to force the fluid through the filter and into the cavity in the plunger.
2 more elements
A method of filtering fluids, comprising:
- placing fluid in a tubular vial having an open top and closed bottom joined by a cylindrical sidewall, the bottom having a protrusion that extends in the direction of the open top;
- inserting a first end of a tubular plunger into the open top of the vial, the plunger having a longitudinal axis, the first end having a cap fitting over the outer surface of the first end of the plunger to hold a filter between the cap and the plunger, the cap having a portion extending radially outward in a direction away from the longitudinal axis a distance sufficient to form a fluid tight seal with the tubular vial, the cap having a recess therein configured to mate with the protrusion;
- and
- moving one of the plunger and vial toward each other to force fluid through the filter and into the cavity in the plunger until the protrusion is received in the recess in the cap.
1 more element
A method of filtering fluid using a tubular plunger having a filter with a cap over an end of the plunger holding the filter in position, the plunger being sized to fit into a tubular vial and seal against a sidewall of the vial to force fluid in the vial through the filter and into a cavity in the plunger as the distance between the cap and the bottom of the vial are reduced, the method comprising:
- providing the plunger, the plunger further having a recess in the cap;
- and
- providing the vial, the vial further having a protrusion on the bottom of the vial extending into the vial, the protrusion and recess having corresponding locations and mating configurations so the protrusion may fit into the recess when the cap abuts the bottom of the vial.
Dependencies are inferred from the claim text.