Bulk fluid transport

Claim 1

A BULK FLUID TRANSPORT TANK COMPRISING A MAIN TANK HAVING A PISTON MOVABLE LONGITUDINALLY THEREIN, FILLER AND AIR RELEASE OPENINGS IN THE TANK, SAID OPENINGS BEING SO ARRANGED THAT IN ALL POSITIONS OF THE PISTON THERE IS A FILLER AND AIR RELEASE OPENING IN THE TANK AT EACH SIDE OF SAID PISTON, SAID TANK HAVING A FLEXIBLE BAG THEREIN, SAID BAG BEING SO ARRANGED AS TO COMMUNICATE WITH ONE PAIR OF FILLER AND AIR RELEASE OPENINGS AT ONE SIDE OF SAID PISTON, SAID BAG BEING FORMED OF POLYETHYLENE, POLYTETRAFLUORETHYLENE OR THE LIKE AND BEING PROVIDED WITH PLASTIC TUBING ARRANGED HELICALLY ABOUT THE SURFACE OF SAID BAG, SAID TANK BEING FURTHER CHARACTERIZED IN THAT A VACUUM MANIFOLD IS ARRANGED ON THE OUTER SURFACE OF THE TANK AND COMMUNICATES WITH THE INTERIOR OF SAID TANK, SAID MANIFOLD BEING COUPLED TO EXHAUST MEANS WHEREBY AIR MAY BE WITHDRAWN FROM BETWEEN THE BAG AND THE TANK WALL THEREBY CAUSING AN EMPTY BAG TO BE HELD AGAINST THE TANK WALL AND EFFECTING WITHDRAWAL FROM THE TANK OF ANY VAPOUR WHICH MAY PERMEATE THE BAG.