| 摘要 |
A blow molded drum has a port including a neck with exterior buttress threads and a port opening having a sleeve fusion bonded in the neck. The sleeve having a inner cylindrical sealing surface, and a shoulder. A drop-in down tube assembly seats with the shoulder and has an upwardly extending nipple. Either a dispense head or a closure radially seals within the sleeve and is secured by a retainer with interior buttress threads engaging with the exterior threads on the port neck. The dispense head has a first flow duct extending to a nipple engaging portion to seal with the upwardly extending nipple and a second flow duct leading to an annular space around the nipple for a return fluid line or for providing air or a gas for displacing withdrawn fluid. The closure is preferably comprised of a cylindrically shaped interior liner portion for engaging and sealing with the cylindrical sealing surface of the sleeve, such as by an o-ring, and has a pathway which includes the spiral gap between the cooperating buttress threads on the neck and on the retainer. A microporous membrane may be placed in the pathway to allow venting of gases but preclude leakage of the liquid in the drum.
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