| 摘要 |
Pump system provided with either a valve stem (42 or a piston (42'), either having a constant-diameter stroke portion (82, 116) interposed between reduced-diameter portions. At least one stationary sealing member (32, 32') immovably affixed to a pump body (14, 14') is also provided formed to sealingly engage the stroke portion of the valve stem or the piston. The sealing member is also formed to not engage the reduced-diameter portions. As such, the volume of the administered dose is controlled by the stroke length, which, in turn, is a function of the dimensioning of the constant-diameter stroke portion and the dimensioning of the sealing member. Advantageously, with the subject invention, a minimal number of tolerances can be implicated in controlling dosing volume.
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