Energy recovery apparatus

Energy recovery apparatus, comprising:

• a pump with a first cylinder and a first piston therein dividing said first cylinder into a driving chamber and a pumping chamber, said pump having means for filling said pumping chamber with a first liquid of first pressure, said pump further having means for driving said first piston in a pumping stroke with a second liquid at a second pressure in said driving chamber, said pump including means for releasing said first liquid from said pumping chamber during said pumping stroke, said pump also including first means for returning said first piston in a filling stroke, said pump further including first means for exhausting said second liquid from said driving chamber during said filling stroke;
• a motor with a second cylinder and a second piston therein dividing said second cylinder into first and second portions, said motor having means for placing said first portion in fluid communication with a third liquid at a third pressure to move said second piston through a hydraulic power stroke, said motor further having means for allowing expansion of said third liquid into said second portion to change phase and form a vapor and liquid mixture to drive said second piston in an expansion power stroke, said motor including second means for exhausting spent vapor and liquid at a pressure lower than said third pressure from said second portion during the hydraulic power stroke, said motor further including second means for returning said second piston in said hydraulic power stroke;
• means for connecting said first and second pistons for simultaneous movements;
• and
• means for switching from one pump stroke to another and from one motor stroke to another at the same time;
• whereby said pump and said motor recover energy from said second and third liquids to pump said first liquid.

An energy recovery apparatus, comprising:

• a pump with first and second aligned cylinders with first and second pistons therein, respectively, said pistons being connected together with a rod, said first and second pistons dividing said first and second cylinders into first and second driving and pumping chambers, respectively, said rod which connects said pistons together passing through said driving chambers, each of said pumping chambers including first and second check valves, said first check valves allowing fluid to pass into said pumping chambers and said second check valves allowing fluid to pass out of said pumping chambers, said pump further including a four-way, two-position valve, said valve having an input and an output, said valve in said first position placing said input in fluid communication with said first driving chamber and said output in fluid communication with said second driving chamber, said valve in said second position placing said input in fluid communication with said second driving chamber and said output in fluid communication with said first driving chamber, said pump also including means for switching said four-way valve between said positions, said switching means including first and second means for sensing one of said first and second pistons at opposite ends of travel of said pistons;
• a motor having third and fourth cylinders and third and fourth pistons dividing each of said third and fourth cylinders into first and second portions, said motor also having a second rod connecting said third and fourth pistons together, said second rod passing through said second chambers, said motor further having an eight-way, four-position valve, said eight-way valve having a second input and a second output, said four-way valve in said first position placing said input in fluid communication with said first portion of said third cylinder and placing said output in fluid communication with said second portion of said third cylinder and placing said first and second portion of said fourth cylinder in fluid communication with one another, said eight-way valve in said second position placing said input in fluid communication with said first portion of said fourth cylinder and placing said output in fluid communication with said second portion of said fourth cylinder and placing said first and second portions of said third cylinder in fluid communication with one another;
• a drive shaft for connecting one of said first and second pistons with one of said third and fourth pistons, said drive shaft having a cross-sectional area;
• dummy shaft means for extending from the other of said first and second pistons than is attached to said drive shaft to a wall of said cylinder opposite said other piston, said dummy shaft extending means having the same cross-sectional area as said drive shaft;
• and
• means for controlling said eight-way valve and said four-way valve to change positions at the same time;
• wherein when said four-way valve and said eight-way valve are in first positions, said first piston moves through a pumping stroke, said second piston moves through a filling stroke said third piston moves through a hydraulic power stroke and said fourth piston moves through an expansion power stroke, and vice versa for said first and second pistons and said third and fourth pistons when said four-way valve and said eight-way valve are in second positions.

A method for using an energy recovery apparatus to transfer energy from first and second pressurized liquids to a third liquid, said energy recovery apparatus including a pump with a driving chamber and a pumping chamber and first means for reciprocating to simultaneously increase the size of one of the driving and pumping chambers and decrease the size of the other, said pump having means for filling the pumping chamber with the first liquid of a first pressure, said pump further having means for driving the first reciprocating means in a pumping stroke with the second liquid at a second pressure in the driving chamber, said pump including means for releasing the first liquid from the pumping chamber during the pumping stroke, said pump also including first means for returning the first reciprocating means in a filling stroke, said pump further including first means for exhausting the second liquid from the driving chamber during the filling stroke, said energy recovery apparatus further including a motor with a main chamber having first and second portions and second means for reciprocating to simultaneously increase the size of one of the first and second portions and decrease the other, the motor having means for placing said first portion in fluid communication with the third liquid at a third pressure to move said second reciprocating means in a hydraulic power stroke, the motor further having means for allowing expansion of the third liquid into the second portion to change phase and form a vapor and liquid mixture to drive the second reciprocating means in an expansion power stroke, the motor including second means for exhausting spent liquid and vapor at a pressure lower than the third pressure from the second portion during the hydraulic power stroke, the motor further including second means for returning the second reciprocating means in the hydraulic power stroke, said energy recovery apparatus further having means for connecting the first and second reciprocating means for simultaneous movement and means for switching from one pump stroke to another and from one motor stroke to another at the same time, said method comprising the steps of:

• directing second liquid into said driving chamber to force said first reciprocating means in a pumping stroke, thereby pumping first liquid from said pumping chamber and placing said first portion of said main chamber in fluid communication with a third liquid at a third pressure to drive said second reciprocating means in a hydraulic power stroke while exhausting third liquid at a lower pressure from said second portion;
• and
• filling said pumping chamber with first liquid at a first pressure while exhausting second liquid from said driving chamber and expanding said third liquid from said first portion into said second portion to form a vapor and liquid mixture and drive said second reciprocating means in an expansion power stroke.