Fluid handling – Self-proportioning or correlating systems – Supply and exhaust type
Reexamination Certificate
1999-10-20
2001-04-03
Buiz, Michael (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Supply and exhaust type
C137S627500, C137S627000, C137S627000
Reexamination Certificate
active
06209565
ABSTRACT:
TECHNICAL FIELD
This invention relates to a hydraulic piloted, manifold cartridge valve. More particularly, the cartridge valve of the invention is pulse operated and may be closed by applying a second pulse or by reducing the supply pressure to the valve.
BACKGROUND ART
Cartridge valves are used in the fluid power and hydraulic control systems industries as a mechanism to control the flow of a pressurized fluid to an end user device, such as hydraulic cylinders or subsea tree actuators. Cartridge valves typically require an external pilot source, such as piloting solenoid valves, to provide a hydraulic pressure to the internal actuating pistons located in the cartridge valve. When pilot pressure is applied to a cartridge valve piston surface, the piston travels through the cylinder, providing axial movement of a valve seal mechanism. The valve seal mechanism opens or closes multiple ports for fluid transfer from one hydraulic buss to another.
Current methods of control for hydraulic piloted, manifold cartridge valves include manually operated valves that supply the cartridge valve with pilot pressures or solenoid operated piloting valves. Solenoid operated piloting valves require electrical power to actuate the piloting valve mechanism. Solenoids requiring continual electrical supply to maintain pilot supply pressure to the cartridge poppet valve use large amounts of electrical energy and create excessive heat. By creating a pressure latched cartridge poppet valve, the solenoid operated pilot valves can be de-energized, thereby saving electrical demand and consumption, and considerably reducing excessive heat.
SUMMARY OF INVENTION
A pulse piloted cartridge valve is pulse operated and defaults to a closed position when supply pressure is lost. The pulse piloted cartridge valve has a housing defining a piston chamber, a supply port, a vent port and a control port. A latching piston assembly is slidably located in the piston chamber. A spring biases the latching piston assembly to a closed position wherein the supply port is sealed off from the control port. A pilot open piston is slidably received on an upper stem of the latching piston assembly within the piston chamber. The pilot open piston divides the piston chamber into a pilot open chamber above the pilot open piston. An axial or first passageway within the latching piston assembly is in communication with the vent port. A poppet cavity communicates with the control port, the vent port, the supply port and the axial passageway.
In operation, the pulse piloted cartridge valve defaults to a closed position due to the spring biasing against the latching piston assembly. In a closed position, the supply port is sealed off from a control port. Pressurized fluid is provided in the pilot open chamber to move the pilot open piston downward on the upper stem of the latching piston assembly to push the latching piston assembly to an open position. Fluid pressure is vented from the latching chamber, which is located below the pilot open piston, through the axial passageway within the latching piston assembly and out of the vent port to accommodate the downwardly moving pilot open piston. The control passageway from the control port to the supply port is opened and the control passageway from the control port to the axial passageway is opened when the latching piston assembly is moved downward. Pressure is then transferred from the supply port through the axial passageway to the latching chamber. The pilot open piston is raised by the pressure from the axial passageway. The latching piston assembly is held in the open position with the pressure within the latching chamber. At this time, the pressure provided to the pilot open chamber may be removed and the latching piston will remain in the open position.
The pulse piloted cartridge valve of the invention may be closed by one of two methods. First, pressurized fluid may be provided to a pilot closed chamber to force the latching piston assembly to a closed position with the aid of a bias spring. Second, pressure from the supply port may be decreased, pressure from the latching chamber may be vented through the axial passageway, and the latching piston assembly will be returned to a closed position by the spring.
REFERENCES:
patent: 3400734 (1968-09-01), Rosenberg
patent: 3520511 (1970-07-01), Warne
patent: 4004610 (1977-01-01), Theriot
patent: 4877046 (1989-10-01), Albrigtsen et al.
patent: 5174544 (1992-12-01), Emanie
Hughes Timothy Lloyd
Smith John Douglas
Bracewell & Patterson LLP
Bradley James E.
Buiz Michael
DTC International, Inc.
Krishnamurthy Ramesh
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