An egg-shaped closed tank used to transport a liquid or slurry by using compressed air. By applying a pressure into the surface of the liquid in the tank, the liquid is forced out by displacement through a dip leg that extends into the liquid. Since the tank does not involve complex and expensive pumps other than a supply of compressed air, it is useful for transporting corrosive liquids such as very concentrated acids. It is also known as an acid egg on account of its shape and application.