An electric eccentric hemisphere valve is a type of valve that uses an electric motor as a power source to control the opening and closing of the valve by controlling the rotation of the motor. It features an eccentric hemisphere design, controlling fluid flow by rotating the hemisphere. It is characterized by low flow resistance, good sealing performance, corrosion resistance, and long service life. Electric eccentric hemisphere valves are widely used in petroleum, chemical, metallurgical, power, urban water supply, and sewage treatment industries, serving as a highly efficient, safe, and reliable fluid control device.
Structural Composition
Valve Body
Eccentric Ball Valve Core: Employs a double or triple eccentric design (valve shaft offset from the valve body center and sealing surface center). The valve disc is hemispherical, forming a line contact seal with the valve seat, resulting in concentrated sealing pressure and excellent sealing performance.
Material Selection: Valve body materials include carbon steel, stainless steel, and alloy steel; sealing surfaces commonly use hard alloys (such as Stellite alloy), ceramics, or wear-resistant weld overlay materials, suitable for high-temperature, high-pressure, and corrosive media.
Electric Actuator Section
Drive Type: Divided into rotary electric actuators (matching 90° rotating eccentric ball valves) and linear electric actuators (requires gear conversion mechanism adaptation).
Control Method: Supports on/off type (fully open/fully closed) and regulating type (4-20mA signal control of opening degree).
Additional Functions: Can integrate intelligent modules such as position feedback, torque protection, remote monitoring, and fault diagnosis.
Working Principle
Electric Drive
The actuator receives control signals (such as DC4-20mA, DC24V switching signals, or RS485 communication protocol). The motor inside the actuator rotates, transmitting power to the valve stem via a reduction gear.
The valve stem drives the hemispherical valve disc to rotate eccentrically, opening or closing the valve.
Sealing Mechanism
When opening: The valve disc quickly disengages from the sealing surface, reducing friction and lowering operating torque.
When closing: The valve disc, through eccentric wedge action, compresses the sealing surface, forming a hard metal seal or a soft seal (such as a rubber lining), ensuring zero leakage.
Advantages
Automated Control
Supports remote operation, timed control, or integration with DCS/PLC systems for unattended operation and improved production efficiency.
High-Precision Regulation
Regulating electric actuators can precisely control valve opening (accuracy ±1%), adapting to fine-tuning needs for flow, pressure, and temperature.
Low Torque, Long Lifespan
Eccentric structure reduces friction, resulting in low output torque requirements for the electric actuator and extending the lifespan of the motor and transmission components.
Frequent wear on sealing surfaces, long maintenance cycles, and low overall cost.
Fast Response
Electric actuators offer fast opening and closing speeds (typically <10 seconds), suitable for emergency shut-off or rapid adjustment scenarios.
Safe and Reliable
Integrates overload protection, automatic power-off reset, and explosion-proof design (Ex certified), adapting to hazardous working conditions.
Applications
Oil & Gas
Remote control valves for long-distance pipelines, refineries, and natural gas processing stations.
Chemical Industry
Transportation of corrosive media, and regulation of inlet and outlet flow rates in reaction vessels.
Power Industry
Automatic control of boiler feedwater, steam pipelines, and cooling water systems.
Water Treatment
Flow regulation and shut-off in wastewater treatment plants, seawater desalination plants, and water supply pipelines.
Metallurgical Industry
Remotely operated valves for high-temperature molten metal conveying and dust removal systems.
Building HVAC
Balancing and regulation of central air conditioning systems and heating networks.