Reciprocating pump flow control
A multi-throw reciprocating pump is provided. The pump provides active stroke control. Fluid flow is controlled by canceling out at least a portion of a discharge stroke of one plunger with a suction stroke of another plunger. Controlling the degree to which the discharge stroke is cancelled out is used to control the actual volume of fluid being pumped.
1. A reciprocating pump comprising:
(a) A first sleeve defining a first compression chamber;
(b) A first plunger receivable in the first sleeve;
(c) A second sleeve defining a second compression chamber, the second compression chamber in fluid communication with the first compression chamber;
(d) A second plunger receivable in the second sleeve;
(e) At least one outlet and at least one inlet in fluid communication with both the first and second compression chambers;
(f) A first crankshaft coupled to the first plunger, the first crankshaft drivingly coupled to a prime mover;
(g) A second crankshaft coupled to the second plunger, the second and first crankshafts coupled to each other through a differential and rotatable about a common crankshaft axis;
(h) a differential housing for housing the differential, the differential housing rotatable about the common crankshaft axis;
(i) rotation means for rotating the differential housing;
whereby rotation of the differential housing effects a phase shift between strokes of the first and second plungers ranging from −180° to 180° to modulate effective flow of fluid out of the outlet.
2. A pump according to claim 1 wherein the differential comprises a differential gear assembly.
3. A pump according to claim 2 wherein the differential gear assembly comprises a differential planet gear.
4. A pump according to claim 1 wherein the first plunger is coupled to the first crankshaft by a first connection rod, and the second plunger is coupled to the second crankshaft by a second connection rod.
5. A pump according to claim 1 wherein the first compression chamber and the second compression chamber are in fluid communication through a fluid passage.
6. A pump according to claim 5 wherein the fluid passage is located adjacent to the at least one outlet.
7. A pump according to claim 1 wherein the rotation means comprises a worm gear driven by a motor.