초록 ▼

A hydraulically driven pump includes a diaphragm, a piston, a transfer chamber, a fluid reservoir, and a valve spool. The transfer chamber is defined between the diaphragm and piston and is filled with a hydraulic fluid. The fluid reservoir is in fluid communication with the transfer chamber via at

A hydraulically driven pump includes a diaphragm, a piston, a transfer chamber, a fluid reservoir, and a valve spool. The transfer chamber is defined between the diaphragm and piston and is filled with a hydraulic fluid. The fluid reservoir is in fluid communication with the transfer chamber via at least one valve. The valve spool is configured to control fluid flow between the transfer chamber and the fluid reservoir. The valve spool is movable to open and close an opening into the at least one valve only when an overfill condition or an underfill condition exists in the transfer chamber. The valve spool is moveable along an axis that is non-coaxial with an axis of movement of the diaphragm.

대표청구항 ▼

I claim: 1. A diaphragm pump, comprising: a diaphragm movable between first and second positions along a first axis; a pumping chamber on one side of the diaphragm, the pumping chamber adapted to carry a fluid to be pumped; a transfer chamber on the other side of the diaphragm, the transfer chamber

I claim: 1. A diaphragm pump, comprising: a diaphragm movable between first and second positions along a first axis; a pumping chamber on one side of the diaphragm, the pumping chamber adapted to carry a fluid to be pumped; a transfer chamber on the other side of the diaphragm, the transfer chamber being filled with a hydraulic fluid; first and second one-way valves; a fluid reservoir in fluid communication with the transfer chamber via the first valve and a first conduit leading directly to the fluid reservoir, and the second valve and a second conduit extending directly from the fluid reservoir to the transfer chamber; and a valve spool positioned in the transfer chamber to control fluid flow through the first and second valves, the valve spool moveable along a second axis that is different from the first axis between a plurality of positions relative to openings to the first and second valves. 2. The diaphragm pump of claim 1, wherein the valve spool is moveable between a first position covering the openings to the first and second valves, a second position covering the opening to the first valve and removed from the opening to the second valve, and a third position covering the opening to the second valve and removed from the opening to the first valve. 3. The diaphragm pump of claim 2, wherein the valve spool is configured to maintain the first position until an overfill condition or an underfill condition is generated in the transfer chamber that moves the valve spool. 4. The diaphragm pump of claim 1, further comprising a valve arm coupled to the diaphragm and configured to engage the valve spool to move the valve spool when an overfill condition or an underfill condition is generated in the transfer chamber. 5. The diaphragm pump of claim 4, wherein the valve spool includes a recess portion, and a portion of the valve arm is moveable within the recess portion without moving the valve spool until the overfill condition or the underfill condition is generated. 6. The diaphragm pump of claim 1, further comprising a diaphragm rod assembly, the diaphragm rod assembly including a diaphragm rod and a biasing member, the diaphragm rod being secured to the diaphragm and the diaphragm rod assembly configured to apply a bias force to the diaphragm in a direction along the first axis. 7. The diaphragm pump of claim 6, further comprising a plunger piston configured for reciprocal movement in the pump, wherein the plunger piston and diaphragm rod are biaxial with each other to provide asynchronous movement of the piston and diaphragm. 8. The diaphragm pump of claim 6, wherein the diaphragm rod assembly is configured to generate a pressure condition in the transfer chamber that is greater than a pressure condition in the pumping chamber. 9. The diaphragm pump of claim 1, wherein the valve spool includes a fluid path defined along at least a portion of a length of the valve spool to provide fluid flow between the transfer chamber and the first and second valves. 10. A hydraulically driven pump, comprising: a diaphragm moveable about a first axis; a piston; a transfer chamber defined between the diaphragm and piston, the transfer chamber being filled with a hydraulic fluid; a fluid reservoir in fluid communication with the transfer chamber via a first one-way check valve and a first conduit leading directly to the fluid reservoir and a second one-way check valve and a second conduit extending directly from the fluid reservoir to the transfer chamber; and a valve spool configured to control fluid flow between the transfer chamber and the fluid reservoir, the valve spool moveable relative to the first and second valves when an overfill condition or an underfill condition exists in the transfer chamber, the valve spool arranged non-coaxial with the first axis. 11. The hydraulically driven pump of claim 10, further comprising a diaphragm rod assembly coupled to the diaphragm and moveable along the first axis, the diaphragm rod assembly configured to apply a biasing force to the diaphragm. 12. The hydraulically driven pump of claim 10, further comprising a valve arm coupled to the diaphragm and configured to engage the valve spool to move the valve spool when the overfill condition or the underfill condition is generated. 13. The hydraulically driven pump of claim 10, wherein the valve spool moves in a direction parallel to the first axis. 14. A method of balancing fluid pressure in a hydraulically driven diaphragm pump, the diaphragm pump including a diaphragm, a piston, a transfer chamber interposed between the diaphragm and the piston, a fluid reservoir, a valve spool, and a first one-way valve and a first conduit providing fluid flow from the transfer chamber directly to the fluid reservoir and a second one-way valve and a second conduit providing fluid flow directly from the fluid reservoir to the transfer chamber, the method comprising the steps of: moving the piston to move the diaphragm along a first axis; and moving the valve spool relative to the first one-way valve and the second one-way valve to control fluid flow between the fluid reservoir and the transfer chamber, wherein the valve spool moves along a second axis that is non-coaxial with the first axis. 15. The method of claim 14, wherein moving the valve spool includes maintaining the valve spool in a first position restricting fluid flow through the first valve while the diaphragm moves until an overfill condition of fluid in the transfer chamber is generated and restricting flow through the second valve while the diaphragm moves until an underfill condition of fluid in the transfer chamber is generated. 16. The method of claim 14, wherein moving the valve spool includes engaging the valve spool with a valve arm, the valve arm being coupled to the diaphragm. 17. The method of claim 14, the valve spool defining a recess in its side, wherein the first valve is configured to permit fluid flow from the transfer chamber to the fluid reservoir and the second valve being configured to permit fluid flow from the fluid reservoir to the transfer chamber, wherein moving the valve spool includes moving the valve spool to a first position to expose an opening to the first valve and cover an opening to the second valve when an overfill pressure condition exists, and moving the valve spool to a second position to close the opening to the first valve and to expose an opening to the second valve when an underfill pressure condition exists. 18. The method of claim 17, wherein the valve spool maintains the second position during a steady state operation of the diaphragm pump to compensate for leakage of fluid from the transfer chamber via the piston. 19. The method of claim 14, wherein the diaphragm pump further includes an air bleed member, the method further comprising permitting passage of air out of the transfer chamber through the air bleed member while substantially restricting the flow of liquid from the transfer chamber. 20. The diaphragm pump of claim 1, further comprising a plunger piston configured for reciprocal movement in the pump, wherein the plunger piston and the spool extend in a substantially parallel direction. 21. The diaphragm pump of claim 2, the valve spool defining a recess in the side of the valve spool, wherein the valve spool is configured so that the end of the valve spool uncovers the first valve in the second position to provide fluid communication between the transfer chamber and the fluid reservoir, and the recess uncovers the second valve in the third position to provide fluid communication between the transfer chamber and the fluid reservoir.