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(11) | EP 0 614 702 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Fluid pump dispenser for pharmaceutical applications |
| (57) The dispenser comprises a first cylinder (11), a first hollow piston (2) disposed
slidably in the first cylinder (11), a second cylinder (12) coaxial with the first
cylinder (11) and forming a prolongation thereof of smaller diameter, the inner wall
of the second cylinder (12) having an enlarged horizontal annular recess (13) at the
jontion of the first and second cylinders, a second piston (3) disposed slidably in
the second cylinder (12), a vertical stem (4) disposed slidably within the first piston
(2) and engaging the second piston (3) and a spring (6) extending within the second
cylinder (13) between its lower end and the lower end of the second piston (3). The first piston (2) is provided with an enlargement (14) intermediate its ends defining an upper portion (27A) and a lower portion (27B). The upper portion (27A) extends slidably above and within the first cylinder (11) and the lower portion (27B) extends slidably within the first cylinder (11) and the second cylinder (12). The enlargement (14) peripherally engages and defines a first unbroken seal (S1) with the inner surface of the first cylinder (11). The second piston (3) peripherally engages and defines a second seal (S2) with the inner surface of the second cylinder (12), the second seal (S2) being unbroken except when the second piston (3) is aligned with and spaced from the annular recess (13). The lower portion (27B) of the first piston (2) is provided with a plurality of vertical grooves (30) or helical grooves (31). |