Abstract: An energy conversion system comprising: a riser conduit comprising a first liquid; a down-comer comprising a second liquid, the down-comer in fluid communication with the riser conduit, the second liquid comprising first liquid and finely divided material in suspension such that the second liquid has a higher specific gravity than the first liquid, the down-comer in fluid communication with a first tank and a second tank; a converter device arranged to convert energy of the first liquid into energy for output from the energy conversion system, and to discharge the first liquid thereafter; and a recirculator arranged to recirculate third liquid to maintain the finely divided material in suspension, the third liquid comprising second liquid and further finely divided material in suspension. The recirculator is arranged to discharge the third liquid to mix with the first liquid from the converter device to form the second liquid.

Abstract: An energy conversion system comprising: a riser conduit comprising a first liquid; a down-comer comprising a second liquid, the down-comer in fluid communication with the riser conduit, the second liquid comprising first liquid and finely divided material in suspension such that the second liquid has a higher specific gravity than the first liquid, the down-comer in fluid communication with a first tank and a second tank; a converter device arranged to convert energy of the first liquid into energy for output from the energy conversion system, and to discharge the first liquid thereafter; and a recirculator arranged to recirculate third liquid to maintain the finely divided material in suspension, the third liquid comprising second liquid and further finely divided material in suspension. The recirculator is arranged to discharge the third liquid to mix with the first liquid from the converter device to form the second liquid.

Abstract: Apparatus for providing motive power comprises first and second communicating columns (10, 14) of liquid, the liquid in the second column being substantially the same as in the first column but containing a finely divided material to increase its specific gravity relative to the liquid in the first column, means (28) for maintaining the finely divided material in suspension in the second column, whereby liquid height in the respective columns is different, so that liquid from the first column overflows into the second column, means for converting energy from resultant movement of liquid into motive power and means (26) for returning the liquid to the first column.