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US 4,501,291 AGranted
Relief valve arrangement
AssigneeVickers, Incorporated
InventorRonald Siegrist
Life of this patent
Estimating the term…
Abstract
Relief valve arrangement comprising a pressure limiting relief valve, the pressure setting thereof can be switched by an auxiliary piston between two or more ranges so that the control pressure, which is obtained by a pilot valve, can be within a region, which can be controlled accurately.
Claims6
Relief valve arrangement for limiting system pressure within two selectable ranges of pressure settings, the arrangement comprising:
- means for delivering control pressure, means for delivering low pressure and
- a main relief valve having a valve body including an inlet chamber connected to system pressure, an outlet chamber connected to low pressure, a first control chamber and a second control chamber,
- a first piston formed as a valve member having a first piston area at said inlet chamber and a second piston area at said first control chamber,
- a second piston having a third piston area and a fourth piston area at said second control chamber, said fourth piston area being distinctly different in size from said second piston area, and
- a directional valve for connecting said control pressure to said first control chamber and said low pressure to said second control chamber, or said control pressure to said second control chamber and said low pressure to said first control chamber.
2 more elements
Relief valve arrangement comprising means for delivering system pressure, means for delivering control pressure, means for deliverying low pressure,
- a first main valve having a valve body including an inlet chamber connected to system pressure, an outlet chamber connected to low pressure, a first control chamber and a second control chamber,
- a first piston formed as a valve member having a first piston area at said inlet chamber and a second piston area at said first control chamber,
- a second piston having a third piston area which comprises pushing means to act upon said first piston, and a fourth piston area at said second control chamber, said fourth piston area being distinctly different in size from said second piston area,
- a second main valve having a valve body including an inlet chamber connected to system pressure, an outlet chamber connected to low pressure, a third control chamber of the same type as said first chamber of said first main relief valve,
- a third piston formed as a valve member having said first piston area at said inlet chamber and said second piston area at said third control chamber, and
- a directional valve having two positions, one for connecting said control pressure to said second control chamber and said low pressure to said third control chamber, or--in the second position of the valve--said control pressure to said third control chamber and said low pressure to said second control chamber.
3 more elements
Dependencies are inferred from the claim text.