Patent ID: 7037081

Claim:
A method for controlling a reciprocating pump comprising two cylinders with associated pistons, one discharge check valve for each cylinder, and at least one closed interval [α 0 , α 2 ] where α is an angular displacement, α 0 is an angular displacement when a first piston is at bottom dead center, and α 2 is an angular displacement when a second cylinder's discharge check valve closes; the method comprising the steps of: (a) operating the reciprocating pump at a constant angular speed except through the closed interval between the angular displacement when the first piston is at bottom dead center and the angular displacement when the second cylinder's discharge check valve closes, [α 0 , α 2 ]; and (b) varying an angular speed of the reciprocating pump to maintain a constant pump discharge pressure through the closed interval [α 0 , α 2 ].