摘要 |
<p>Embodiments of the invention provide liquid pump apparatus. The apparatus may comprise an immersion assembly comprising at least one immersion member having a liquid conduit provided therein along at least a portion of a length thereof, the immersion assembly being arranged whereby in use at least a portion of the immersion assembly is immersed in liquid to be pumped, the apparatus being arranged to provide a supply of gaseous fluid to liquid in the tank through the at least one immersion member at one of a plurality of vertically spaced apart locations of the assembly thereby to cause passage of liquid through the assembly from a liquid inlet aperture to a liquid outlet aperture of the assembly, the apparatus being configured whereby a location at which gaseous fluid is supplied to the immersion assembly is selected to be a location at which a head of pressure of liquid in the tank is within a prescribed range of values.</p> |