Patent ID: 8097224

Claim:
An apparatus for covering a vessel that contains a fluid, the apparatus comprising: a cap for engaging the vessel, the cap having: a first external side; a second internal side that is exposed to a fluid contained in the vessel, wherein the second side comprises a conical member that facilitates deposition of a condensate from the fluid back into the fluid; a flange disposed between the first external side and the second internal side of the cap; a central port disposed in the cap adapted to receive a rotatable rod, wherein: the central port comprises a polytetrafluoroethylene material disposed on a portion of the port that contacts the rotatable rod; and the portion of the central port that contacts the rotatable rod creates a seal with the rotatable rod that inhibits escape of a material contained within the vessel into the external environment; a sample port disposed in the cap, wherein: the sample port is adapted to allow a user to obtain a sample of the solution from within the vessel or to introduce a composition into the vessel; a sealing member disposed on the cap that contacts the vessel that contains the fluid so as to create a seal with the vessel that inhibits escape of a material within the vessel into the external environment when the cap is operatively engaged with the vessel; wherein a portion of the cap that contacts fluid in the vessel is comprised of a material that is resistant to degradation by a solution comprising: phosphate buffered saline at pH range of pH 5 to pH 7; 1-7% limonene; 0.3-5% sodium dodecyl sulfate; and the apparatus inhibits fluid loss from the vessel due to evaporation.