Control valve unit for a hydraulic servo motor for a control valve of a turbine
A valve system for controlling the flow of hydraulic fluid for opening and closing the main control valve for a turbine system is described. The valve system comprises: first valve means for passing hydraulic fluid to the servo motor to maintain the control valve open during normal operating conditions of the turbine and to interrupt the supply of hydraulic fluid in response to a predetermined normal pressure drop; second valve means for draining hydraulic fluid from the servo motor to close the control valve in response to a predetermined normal pressure drop in the turbine system; and third valve means for separately draining hydraulic fluid from the servo motor to relieve the latter of pressure rapidly in response to an abnormal pressure drop in the turbine system with consequent rapid closing of the control valve.
- Assignee:
- Stal-Laval Turbin AB
- Patent Number(s):
- US 4025222
- OSTI ID:
- 7105659
- Resource Relation:
- Patent Priority Date: Priority date 24 Apr 1973, Sweden
- Country of Publication:
- United States
- Language:
- English
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