Fluid transfer devices for transferring fluid into or out of fluid vessels in a substantially aseptic, hygienic, or sterile manner. The devices have a body with a proximal and distal end. An elongate passage extends through the body. Longitudinally displaceable shafts, which may be substantially hollow, are disposed in and extend along the passage. A plug seals the passage at a first location. A diaphragm seals the passage at a second location intermediate the plug and the distal end of the passage. Shafts extend through and are secured to the diaphragm and may have a fluid transfer opening between the diaphragm and the plug or a fluid transfer opening may be located in the passage between the diaphragm and the plug. Longitudinal displacement of the shafts causes fluid transfer, the diaphragm stretching to accommodate the displacement of the shaft while maintaining an aseptic seal of the passage.
