Continuous flow multi-piston pump

Abstract

A multi-piston pump includes a first pump configured to execute a discharge stroke, a suction stroke, a compression stroke, a hold, and a changeover, a second pump independent from the first pump, the second pump being configured to execute a discharge stroke, a suction stroke, a compression stroke, a hold, and the changeover; and a controller that coordinates operation of the first pump and the second pump so that while the first pump is executing the discharge stroke, the second pump is executing the suction stroke, the compression stroke, and the hold, and the first pump and the second pump execute the changeover simultaneously and while the second pump is executing the discharge stroke, the first pump is executing the suction stroke, the compression stroke, and the hold and the first pump and the second pump execute the changeover simultaneously

1 . A multi-piston pump comprising:
 a first pump configured to execute a discharge stroke, a suction stroke, a compression stroke, a hold, and a changeover;   a second pump independent from the first pump, the second pump being configured to execute a discharge stroke, a suction stroke, a compression stroke, a hold, and the changeover; and   a controller that coordinates operation of the first pump and the second pump so that:
 while the first pump is executing the discharge stroke, the second pump is executing the suction stroke, the compression stroke, and the hold, and the first pump and the second pump execute the changeover simultaneously; and 
 while the second pump is executing the discharge stroke, the first pump is executing the suction stroke, the compression stroke, and the hold, and the first pump and the second pump execute the changeover simultaneously. 
   
     
     
         2 . The multi-piston pump of  claim 1 , wherein during the changeover, the first pump is executing the discharge stroke and the second pump is executing the discharge stroke. 
     
     
         3 . The multi-piston pump of  claim 1 , wherein the first pump comprises a first linear position sensor configured to sense and send to the controller position information of the first pump, and the second pump comprises a second linear position sensor configured to sense and send to the controller position information of the second pump. 
     
     
         4 . The multi-piston pump of  claim 3 , wherein the first pump comprises a first pressure sensor configured to sense and send to the controller pressure information of the first pump, and the second pump comprises a second pressure sensor configured to sense and send to the controller pressure information of the second pump. 
     
     
         5 . The multi-piston pump of  claim 4 , wherein the controller coordinates operation of the first pump and the second pump based upon position information of the first pump, position information of the second pump, pressure information of the first pump, and pressure information of the second pump. 
     
     
         6 . The multi-piston pump of  claim 1 , wherein the multi-piston pump is configured to output a continuous volumetric output during the changeover between the first pump and the second pump. 
     
     
         7 . The multi-piston pump of  claim 1 , wherein during the discharge stroke of the first pump, a first discharge poppet valve fluidly connected to a first delivery cylinder of the first pump is open, and during the discharge stroke of the second pump, a second discharge poppet valve fluidly connected to a second delivery cylinder of the second pump is open. 
     
     
         8 . The multi-piston pump of  claim 7 , wherein during the suction stroke of the first pump, a first suction poppet valve fluidly connected to the first delivery cylinder is open and the first discharge poppet valve is closed, and during the suction stroke of the second pump, a second suction poppet valve fluidly connected to the second delivery cylinder is open and the second discharge poppet valve is closed. 
     
     
         9 . The multi-piston pump of  claim 8 , wherein during the changeover between the first pump and the second pump, the first discharge poppet valve is open and the second discharge poppet valve is open. 
     
     
         10 . The multi-piston pump of  claim 8 , wherein the first pump and the second pump are hydraulic pumps. 
     
     
         11 . The multi-piston pump of  claim 10 , wherein hydraulic fluid is routed to a piston to tank orifice after completion of the discharge stroke. 
     
     
         12 . The multi-piston pump of  claim 8 , wherein during the compression stroke of the first pump, the first discharge poppet valve is closed and the first suction poppet valve is closed, and during the compression stroke of the second pump, the second discharge poppet valve is closed and the second suction poppet valve is closed. 
     
     
         13 . The multi-piston pump of  claim 12 , wherein during the compression stroke of the first pump, the pressure in the first delivery cylinder increases until the pressure in the first delivery cylinder is just below a pressure in the second delivery cylinder, and during the compression stroke of the second pump, the pressure in the second delivery cylinder increases until the pressure in the second delivery cylinder is just below a pressure in the first delivery cylinder. 
     
     
         14 . The multi-piston pump of  claim 13 , wherein when the pressure in the first delivery cylinder is just below a pressure in the second delivery cylinder, the pressure in the first delivery cylinder is just below the opening pressure of the first discharge poppet valve, and when the pressure in the second delivery cylinder is just below the pressure in the first delivery cylinder, the pressure in the second delivery cylinder is just below the opening pressure of the second discharge poppet valve. 
     
     
         15 . The multi-piston pump of  claim 13 , wherein during the hold of the first pump, the pressure in the first delivery cylinder is just below a pressure in the second delivery cylinder and the second delivery cylinder is executing the discharge stroke, and during the hold of the second pump, the pressure in the second delivery cylinder is just below a pressure in the first delivery cylinder and the first delivery cylinder is executing the discharge stroke. 
     
     
         16 . The multi-piston pump of  claim 8 , wherein the multi-piston pump has a discharge pipe that is connected to the first delivery cylinder and the second delivery cylinder. 
     
     
         17 . The multi-piston pump of  claim 8 , wherein the first suction poppet valve is an intake control valve for the first delivery cylinder, the first discharge poppet valve is an exhaust control valve for the first delivery cylinder, the second suction poppet valve is an intake control valve for the second delivery cylinder, and the second discharge poppet valve is an exhaust control valve for the second delivery cylinder. 
     
     
         18 . The multi-piston pump of  claim 8 , wherein the first pump comprises a first ram within the first delivery cylinder and the second pump comprises a second ram within the second delivery cylinder. 
     
     
         19 . The multi-piston pump of  claim 18 , and wherein during the changeover from the first pump to the second pump, the first ram ramps down speed while the second ram ramps up speed, the pressure in the first delivery cylinder decreasing and the pressure in the second delivery cylinder increasing, and during the changeover from the second pump to the first pump, the second ram ramps down speed while the first ram ramps up speed, the pressure in the second delivery cylinder decreasing and the pressure in the first delivery cylinder increasing. 
     
     
         20 . The method of  claim 18 , wherein a rate of rearward movement of the first ram is greater than a rate of forward movement of the second ram when the first pump is executing the suction stroke, and a rate of rearward movement of the second ram is faster than a rate of forward movement of the first ram when the second pump is executing the suction stroke.