Valve Operation Applications With The KVA Valve Actuator
KVA for General Purpose Valve Actuation
The Kinitics Valve Actuator (KVA) is a shape memory alloy-based electric control valve actuator. It employs Bundled Wire technology to deliver direct linear motion, avoiding the backlash inherent to gear trains and ball screws. Its innovative mechanics allow for constant motion to maintain precise control of gas and fluids in process control applications. The versatile KVA platform is designed to replace traditional pneumatic or electric actuators and can be mated to a wide variety of globe valves for general purpose use.
The KVA is designed specifically for globe valve style valves. Globe valves are process control devices used in applications requiring frequent operation or throttling of flow. A valve stem moves linearly to lift or lower the plug to open or close an internal port. When closed, force is applied to the stem in order to hold back pressure. Globe valves are suitable, and usually preferred, for a variety of control applications such as pressure, flow, and temperature.
Electrically Powered, Mechanical Reassurance
The KVA can be configured to operate from AC or DC power sources. Rated for 100% duty cycle, it can be operated continuously while throttling or holding at a fixed position. A conventional mechanical compression spring provides the closing force. This spring also allows the KVA to fail closed on loss of power or signal.
The KVA accepts common industrial position command signals including 4-20mA analog, discrete digital, and MODBUS. It provides position feedback in the form of a 4-20mA position indicator, valve open signal, and MODBUS. Connections to these feedback outputs are not necessary for operation but can provide valuable information for closed loopcontrol and process optimization.
The Bundled Wire technology used in the KVA allows for a robust drivetrain with only one moving part. The reduction in sliding surfaces to only a single rod passing through a linear bearing results in very low mechanical wear and extends the life of the actuator. The wire bundle develops motion and generates force in a purely linear way, effectively minimizing mechanical backlash and slop inherent to traditional gearboxes.
Downward force is provided by a compression spring acting directly on the stem. This provides reliable mechanical assurance at all times, even if there is a power failure. In lift-to-open installs, the spring is responsible for maintaining closure force against the pressurized process fluid, meaning no energy is consumed to maintain the closed position. To determine force requirements for your application, refer to your valve specification sheet.