Cross-contamination isolator

A liquid isolator to prevent crosscontimination in the supply of liquid to and between animal racks and the like, said isolator comprising an upright cylindrical tubular body having a liquid inlet at its top and a liquid outlet at its bottom, a coaxial standpipe within the tubular body and of smaller diameter than the body, said body and standpipe forming an annular cross section liquid storage chamber therebetween, a liquid entry tube within the standpipe and of smaller diameter than the standpipe to form with the standpipe an annular cross section standpipe chamber therebetween, said standpipe having base means on which the entry tube is supported, a liquid entry port at the upper end of the entry tube communicating with said liquid inlet and a liquid exit port near the lower end of the entry tube communicating with said standpipe chamber, transfer port means between the standpipe chamber and liquid storage chamber near the upper ends thereof, transfer port means between the storage chamber and the said liquid outlet near the lower end of the storage chamber, the portion of said storage chamber between the transfer port means at the upper end of the storage chamber and the level of any liquid in said chamber constituting an air lock to isolate liquid in the standpipe chamber from the liquid in the storage chamber.