Method and apparatus for an electrohydraulic control system of a steam turbine
US6116258A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1999 |
| Grant date | Sep 12, 2000 |
| Priority date | — |
| Expiry date | Feb 16, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/8663
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
Pilot valves used in electrohydraulic control systems are driven by either an electromagnetic electromechanical actuator or an electromotor electromechanical actuator. A drawback of electromagnetic actuation is that on brief interruptions of electrical power the actuator causes a trip response to the pilot valve, whereas a drawback of electromotor actuation is that on complete interruptions of electrical power the actuator cannot independently cause a trip response of the pilot valve on demand. The proposed modification, involving the pilot valve, provides a means to effect a trip response regardless of the electromechanical actuator type used, together with overcoming the drawback of electromotor actuation. To realize the trip response, an additional piston (connected to the electromotor actuator's stem) is positioned between the actuator stem and the pilot valve. A surface area of the additional piston and one surface area of the pilot valve are loaded by pressure from an oil trip line in the hydraulic system. The loaded surface area of the pilot valve causes a force in the direction opposite to that of a trip, while the force on the additional piston is in the direction required…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.