Intensifier pump with half wave modulator

Claim 2

In a reciprocating intensifier pumping system having two pumping pistons to alternately pump intensifier fluid at a predetermined pressure and at a constant flow rate, a power cylinder having a double ended and double acting working piston connected in line with said pumping pistons, said power cylinder having cylinder ports at opposite ends thereof, a supply pump to deliver hydraulic fluid at a constant rate, a reversing valve operable at each predetermined stroke of the working piston to reverse the connections of said cylinder ports across said pump and conduct hydraulic fluid therebetween, said reversing valve having an inlet port at an open center in said valve between a pair of outlet ports closely connected respectively to said cylinder ports, said inlet port connected to a delivery line from said supply pump, a pair of return ports next adjacent said outlet ports and connected to a return to said supply pump, a valve member having a pair of spaced apart lands defining said open center and biased to a normally inoperative center position in which said lands open said outlet ports to each other through said valve center while blocking said outlet ports to said return, said valve member having two operating fluid directing control positions, in one of said operating positions of said valve member said valve connects said inlet port to a first of said outlet ports and connects a second of said outlet ports to said return, in the other of said operating positions of said valve member said valve connects said inlet port to said second outlet port and connects said first outlet port to said return, said valve member in moving from said one operating position to said other operating position sequentially provides: blocking of said return to flow from said second outlet port, opening of said second outlet port to said valve center and to flow from said first outlet port, blocking of said first outlet port to said valve center and to flow from said second outlet port, and opening of said first outlet port to said return, said working piston at the end of a stroke in said power cylinder defines large and small volume ends respectively on opposite sides of the working piston, and means timing the rate of movement of said valve member in shifting from one operating position to the other operating position so that while said valve member is in transit between said operating positions the valve conducts a very high velocity fluid surge generated by expansion of compressed fluid in said large volume end of the power cylinder to the small volume end thereof and at the time of the peak value of said surge said valve member closes said large volume end to any return of said surge and opens said large volume end to pump return, whereby the momentum of said surge to said low volume end of the power cylinder is effective to initiate a reverse stroke of the working piston.

Claim 3

In a reciprocating intensifier pumping system having two pumping pistons to alternately pump intensifier fluid at a predetermined pressure and at a constant flow rate, a power cylinder having a double ended and double acting working piston connected in line with said pumping pistons, said power Cylinder having cylinder ports at opposite ends thereof, a supply pump to deliver hydraulic fluid at a constant rate, a reversing valve operable at each predetermined stroke of the working piston to reverse the connections of said cylinder ports across said pump and conduct unrestricted flow of hydraulic fluid therebetween, said reversing valve having an inlet port at an open center in said valve between a pair of outlet ports closely connected respectively to said cylinder port, said inlet port connected to a delivery line from said supply pump, a pair of return ports next adjacent said outlet ports and connected to a return to said supply pump, a valve member having a pair of spaced apart lands defining said open center and biased to a normally inoperative center position in which said lands open said outlet ports to each other through said valve center while blocking said outlet ports to said return, said valve member having two operating fluid directing control positions, in one of said operating positions of said valve member said valve connects said inlet port to a first of said outlet ports and connects a second of said outlet ports to said return, in the other of said operating positions of said valve member said valve connects said inlet port to said second outlet port and connects said first outlet port to said return, said valve member in transit between said first and second operating positions sequentially provides that a leading one of said lands blocks communication between said second outlet port and return and opens said second outlet port to the valve center while the first outlet port is still open to the valve center to thereby interconnect said outlet ports and the large and small volume ends of the power cylinder defined by the position of the working piston at the end of a power stroke, and then a trailing one of said lands blocks communication between said first outlet port and said valve center and opens communication between said first outlet port and return; said reversing valve having end chambers each connected respectively through a choke shunted by a check valve poled for flow toward the end chambers and connected through a pilot valve to a source of control pressure and a return, said pilot valve operable at each predetermined stroke of said working piston to reverse the direction of flow of control pressure fluid to said end chambers and return, and said chokes adjustable to time the rate of shifting of said valve member from one operating position to the other operating position so that said reversing valve conducts a high velocity surge of fluid generated by expansion of compressed fluid in said large volume end of the power cylinder to the small volume end thereof, then blocks the return of said surge to said large volume end so that the momentum of said surge provides a hydraulic impact that initiates a reverse stroke of said working piston, and an accumulator connected through a check valve to said delivery line of said pump and operable to discharge hydraulic fluid thereto while the pressure therein is below a working pressure normally sustained by said pump so that said accumulator assists said pump in reverse stroking of the working piston until working pressure is restored.

Claim 4

In a reciprocating intensifier pumping system having two pumping pistons to alternately pump intensifier fluid at a predetermined pressure and at a constant flow rate, a power cylinder having a double ended and double acting working piston connected in line with said pumping pistons, said power Cylinder having cylinder ports at opposite ends thereof, a supply pump to deliver hydraulic fluid at a constant rate, a reversing valve operable at each predetermined stroke of the working piston to reverse the connections of said cylinder ports across said pump and conduct unrestricted flow of hydraulic fluid therebetween, said reversing valve having an inlet port at an open center in said valve between a pair of outlet ports closely connected respectively to said cylinder port, said inlet port connected to a delivery line from said supply pump, a pair of return ports next adjacent said outlet ports and connected to a return to said supply pump, a valve member having a pair of spaced apart lands defining said open center and biased to a normally inoperative center position in which said lands open said outlet ports to each other through said valve center while blocking said outlet ports to said return, said valve member having two operating fluid directing control positions, in one of said operating positions of said valve member said valve connects said inlet port to a first of said outlet ports and connects a second of said outlet ports to said return, in the other of said operating positions of said valve member said valve connects said inlet port to said second outlet port and connects said first outlet port to said return, said valve member in transit between said first and second operating positions sequentially provides that a leading one of said lands blocks communication between said second outlet port and return and opens said second outlet port to the valve center while the first outlet port is still open to the valve center to thereby interconnect said outlet ports and the large and small volume ends of the power cylinder defined by the position of the working piston at the end of a power stroke, and then a trailing one of said lands blocks communication between said first outlet port and said valve center and opens communication between said first outlet port and return; said reversing valve having end chambers each connected respectively through a choke shunted by a check valve poled for flow toward the end chambers and connected through a pilot valve to a source of control pressure and a return, said pilot valve operable at each predetermined stroke of said working piston to reverse the direction of flow of control pressure fluid to said end chambers and return, and said chokes adjustable to time the rate of shifting of said valve member from one operating position to the other operating position so that said reversing valve conducts a high velocity surge of fluid generated by expansion of compressed fluid in said large volume end of the power cylinder to the small volume end thereof, then blocks the return of said surge to said large volume end so that the momentum of said surge provides a hydraulic impact that initiates a reverse stroke of said working piston, and an accumulator connected through a check valve to said delivery line of said pump and operable to discharge hydraulic fluid thereto while the pressure therein is below a working pressure normally sustained by said pump so that said accumulator assists said pump in reverse stroking of the working piston until working pressure is restored.