Patent ID: 7704388

Claim:
A reusable chromatographic device comprising: a one-piece reusable plastic tubular body comprising a first open end having an inside diameter ID 1 ; said body further comprises external threads disposed about said first open end; said body further comprises a tapered rim disposed at said first open end; a one-piece reusable plastic sealing insert comprising a circular base having a perimeter portion; said sealing insert further comprising substantially planar top and bottom surfaces; said sealing insert further comprising a stem extending upward from said base; said stem comprises first and second annular stairs, and an inlet port; said first annular stair has an outside diameter OD 1 ; said second annular stair has an outside diameter OD 2 ; said outside diameter OD 1 of said first annular stair is larger than said outside diameter OD 2 of said second annular stair; said first annular stair bus a height H 1 relative to said top surface of said base; said sealing insert further comprises an annular wall disposed at said perimeter of said base; said annular wall surrounds said first annular stair of said stem; said annular wall is substantially spaced apart from said first annular stair to form an annular recessed portion; said annular wall comprises an upper annular end, an annular sloped surface, and a lower annular protrusion; said upper annular end of said annular wall has a height H 2 relative to said top surface of said base; said height H 1 of said first annular stair is equal to said height H 2 of said upper annular end of said annular wall; said upper annular end of said annular wall has an outside diameter OD 4 that is larger than said ID 1 of said first open end of said tubular body; a one-piece reusable plastic cap comprising a top wall, a central opening disposed in said top wall, and an annular sidewall having internal threads removably engaged with said external threads of said tubular body; said inlet port of said stem passes thru said central opening and extends outward of said top wall of said cap; said central opening has an inside diameter ID 2 ; said inside diameter ID 2 of central opening is less than said outside diameter OD 1 of said first annular stair; and rotation of said cap causes said top wall of said cap to apply a straight downward force upon said upper annular end and said first annular stair of said stem, respectively, of said sealing insert; and said rotation of said cap further causes said annular sloped surface of said sealing insert to form a seal with said tapered rim of said first open end of said tubular body.