International Publication Number WO 00/76906 discloses a coupling device for liquid product packaging and dispensing, with which liquid is pumped from a container via the coupling through a tube to the point of use.  While decoupled, the coupling comprises a first interconnectable member with a hollow post and a seal sleeve spring-biased into a position that it covers (and closes) fluid flow openings in a hollow post, and a second interconnectable member with a hollow sheath and a valve which is spring biased into a closed position at the end of the hollow sheath.  Upon coupling, the post unseats the valve while the sheath displaces the sleeve, thereby allowing liquid flow.  An elastic ring is present between the sheath and the sleeve which ring is compressed in the axial direction and expanded in the radial direction towards the post so as to establish a close fit around the post. 
The coupling device of WO 00/76906 may remain in the coupled position for long periods of time, as the supply container holding the liquid to be dispensed may be supplied as a multiplicity of relatively small aliquots over a relatively long time period.  While in the coupled position, one of the interconnectors has a hollow post open for fluid flow due to a coaxial seal sleeve being forced back from its spring-biased position during the coupling of the interconnectors.  The hollow post has passageways through which liquid is dispensed (from a first hollow body) into the interior of the second interconnector, which liquid thereafter flows towards and into the second hollow body. 
Long periods during which the interconnectors are in the coupled position can result in the drying of liquid on the uncovered outer surface of the hollow post, resulting in a solid residue firmly adhered to the outer surface of the hollow post.  Upon disconnection of the interconnectors from one another, the residue on the outer surface of the hollow post can be adhered to the hollow post to a degree that it prevents the bias spring from forcing the seal sleeve back over the hollow post.  When this occurs, liquid inside the coupling device (together with any liquid inside first hollow body) can drip from the openings in the extended hollow post, with the resulting contamination of the area by the dripping liquid. 
Liquid dripping from the hollow post is undesirable as it is a waste of product and produces a spill which must be recovered and disposed of.  Moreover, the liquid which escapes from the system has the potential to come into contact with the skin of workers and/or damage other objects or supplies.  It would be desirable to have a coupling device in which the passageways through the hollow post are covered upon decoupling, even if the hollow post has been extended for a prolonged period.