Servo Valve

Date:2016-7-12 20:27:33 Visits: Author:Dongfang YOYIK Engineering Co; Ltd,



DEH system of steam turbine is the abbreviation for the digital electro-hydraulic control system of the steam turbine. Servo valve converts the electric signal of valve position of DEH to hydraulic signal, drives the movement of oil slide valve, changes the opening of speed control valve, changes the steam intake volume of the unit, and makes the unit's speed (or load) reach the given value, and the system becomes equilibrium state.


Our servo valves have large flow, high discharge pressure, good performance, high efficiency, long service life, and high reliability, are special technical valve products.


We offer servo valves of various brands:


We also offer: Servo valve Filter, Servo valve plug, Free cleaning and maintenance in 12 months






Servo valveServo valveServo valveServo valve





072-1202-10 072-559A
G761-3033B G761-3034B
J761-001 J761-002
J761-003 J761-004


DSV-001A DSV-001B
W.01.J.0021 W.01.J.0022
W.01.J.0054 W.01.J.0101
W.01.J.0693 W.01.Z.000152
W.01.Z.000172 W.01.Z.000256


PSSV-890-DF0056 PSSV-890-DF0056A


SM4-20(10)38-80/40-50-S10 SM4-20(15)57-20/200-10
SM4-20(15)57-80/40-10-H607 SM4-20(15)57-80/40-10-S182
SM4-20(2.5)9-80/40-10-S10 SM4-40(40)151-80/40-10-S205



Typical Faults of Servo Valve



Faults Cause Possible Damage
Fastener loosening Untightened screw or imperfect anti-loosening design Increased bias may cause servo valve failure
Spring tube fatigue Fatigue Servo valve vibration to rapid failure. Cause the valve to swing until it is fully open or closed.
Partial or total blockage of nozzle or throttle orifice Oil contaminated Bias increase, frequency response decreases dramatically. System becomes unstable.
Filter blocked Oil contaminated Frequency response decreases and system becomes unstable.
Seals aging Service life expired or unsuitable oil Valve cannot work properly, internal and external oil seepage.


From the experience of servo valve inspection and maintenance work over the years, it has been found that oil pollution is the major cause of servo valve jams and damage to consumable parts such as seals. The quality of the oil supply of the EH oil system is critical. It is necessary to select high quality oil and oil filters. This will ensure that the contamination particle size and acid value of EH oil are within the standard range. It is also necessary to regularly check the servo valve per year and enhance the management of the servo valve to prevent accidents caused by the valve itself. 



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