ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: Valve Actuators

1. Okan Gurdil Email: okang@cc.usu.edu Phone: (435)797-6203 ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Topic: Valve Actuators

2. Outline • Reference List • To Explore Further • Major Applications • Spring and Diaphragm • Pneumatic Piston • Electric Motor Drive • Electrohydraulic • Major Specifications • Valve Actuator Characteristics • Key Elements to Valve Actuators

3. Reference list • http://www.rotork.com/ • http://www.tycovalves.com/ • http://www.vetcogray.com/products/fcs/actuators/gate_valve_hydraulic_actuators.cfm • http://www.emersonprocess.com/valveautomation/bettis/Products/Actuator_Matrix.htm • http://www.anson.co.uk/etype.html • http://flow-control.globalspec.com • http://www.ccivalve.com/pdf/264.pdf • http://www.cpc-cryolab.com/PdfFiles/AutoSeal.pdf • http://www.fmctechnologies.com/SurfaceWellhead/Valves/Actuators/HPPNPneumaticPistonActuator.aspx • http://www.ee.polyu.edu.hk/staff/eencheun/WebSubject2/chapter2.htm

4. To Explore Further • http://www.processingtalk.com/indexes/categorybrowseab.html This website has all the required topics about valve actuators • http://www.vici.com/act/mic.htm An interesting website that demonstrates a micro electric valve actuator • http://www.plastomatic.com/ebv.html A very detailed site about the electric ball valve actuators

5. Major Applications • Spring and Diaphragm - Process systems for the industrial gas, chemical, petrochemical, pharmaceutical, aerospace ground support and marine industry. • Pneumatic Piston - Secondary master valve and/or wing valve of a Christmas tree, flow lines, header valves, gathering lines and pipelines. • Electric Motor Drive - Specify the motor speed or shaft position • Electrohydraulic - Flow forces and spool stability

6. Spring and Diaphragm Valve Actuators:Basic Working Principle • A mechanism on the side of the distributor automatically varies the instant at which the spark occurs as a function of intake manifold vacuum • Vacuum advance provides the additional advance that is needed when the engine is operating at part throttle • The vacuum advance mechanism consists of a flexible spring-loaded diaphragm connected by a linkage to the breaker plate on which the points are mounted. • The sealed side of the diaphragm is connected by a tube to the carburetor. • The throttle valve is below the vacuum passage in the carbonator air horn • With wide-open throttle there is very little vacuum in the intake manifold

7. Spring and Diaphragm Valve Actuators:Typical Sample Configuration

8. Advantages Lowest first cost Operating simplicity and reliability Throttles well without positioner Inherent fail-safe operation Low air pressure supply Easily adjustable to local conditions Few moving parts Ease of maintenance Most mature technology Disadvantages Limited force output Large size and weight per unit force Low Stiffness Does not handle high ambient temperatures well Spring and Diaphragm Valve Actuators:Advantages/Disadvantages

9. Some solenoids can move heavier loads, such as the spool in a solenoid-actuated pneumatic or hydraulic valve. The larger the coil, the longer it takes to actuate. Solenoids can be made to act more quickly to move light loads, such as pins in a dot-matrix printer, if larger power supplies are used to drive them. Solenoids, because they are electromagnets, do not exert the same force over their whole stroke. Solenoids can be purchased to pull or to push loads. Solenoids that have built-in linear to rotary converters are also available. Some torque motors contain solenoids. Used to apply a rotational force but not a continuous rotation. Limits on how far the rotor can be caused to rotate. Pneumatic Piston Valve Actuators:Basic Working Principle

10. Pneumatic Piston Valve Actuators:Typical Sample Configuration

11. Advantages High force and torque capacity Moderately compact silhouette Low weight to power ratio Can stand high ambient temperatures Fast stroking speed Good throttling control Few Moving parts Relatively high actuator stiffness Available in smart valve configuration Available in corrosion resistant materials Disadvantages Requires spring or accessories for fail safe operation Must have positioner to function Higher first cost than S&D actuator Requires high pressure air to operate Pneumatic Piston Valve Actuators:Advantages/Disadvantages

12. Electric Motor Drive Valve Actuators:Basic Working Principle • Contains conductors, permanent magnets, or alloy metals selected for their magnetic properties. • Inner rings of the slip ring pair can rotate inside the stationary outer rings without loss of the electrical connection. • Slip rings do not affect the direction of current flow through the rotor. • The rotor or armature is supported on bearings in the housing of the motor. • Many very small motors now come with oil-filled bronze bushings instead of roller bearings. • The stationary housing of the motor (hence stator) provides the magnetic field essential to the operation of the motor. • The field may be provided by permanent magnets or by electromagnets. • In some motors, the orientation of the magnetic field can be controlled.

13. Electric Motor Drive Valve Actuators: Typical Sample Configuration

14. Advantages High force output Very high stiffness Compact silhouette Slow stroking speed (if required) Does not require air supply or I/P Corrosion-resistant seals and construction are available Infrared emote setting unit available Relatively mature technology Good on large valves in remote locations Disadvantages High first cost Not inherently fail safe Limited duty cycle of motor drive Multiple moving parts Electric Motor Drive Valve Actuators: Advantages/Disadvantages

15. Electrohydraulic Valve Actuators:Basic Working Principle • The flow of hydraulic fluid to the two ports of the actuator cylinder is controlled by a servo valve that is controlled by a signal from a servo amplifier that, in turn, receives an analog position-command signal from a supervisory control system of the facility. • As the position command changes, the servo valve shifts, causing a greater flow of hydraulic fluid to one side of the cylinder and thereby causing the actuator piston to move to extend or retract a piston rod from the actuator body. • A linear variable differential transformer (LVDT) directly linked to the piston provides a position-feedback signal, which is compared with the position-command signal in the servo amplifier. When the position-feedback and position-command signals match, the servo valve moves to its null position, in which it holds the actuator piston at a steady position. • The actuator includes a deceleration feature for both extremes of the piston stroke. • When the actuator is used to open and close a valve, the deceleration feature prevents damage to valve seats and other components during cycles of rapid stroking.

16. Electrohydraulic Valve Actuators:Typical Sample Configuration

17. Advantages High force output High actuator stiffness Excellent throttling ability Fast stroking speed Does not require air supply or I/P Accepts harsh environments well Disadvantages Highest first cost Multiple moving parts, highest maintenance Fails safe only with spring or accessories Least mature actuator technology Electrohydraulic Valve Actuators:Advantages/Disadvantages

18. Major Specifications • Media being handled, e.g., liquid, gas, slurry, or solid • Corrosiveness of media, e.g., pH, concentration • Corrosiveness of atmosphere • Flow (velocity, capacity, Cv, direction) • Pipe size • Media temperature (maximum to minimum) • Pressure: maximum operating pressure; maximum differential pressure • Operation: e.g., manual/automatic, on-off throttling • Installation constraints • Envelope dimensions • Weight • Accessibility • Conformance to appropriate standards, e.g., API, AWWA, ANSI, FM, UL, OSHA, etc. • Tightness of shutoff required

19. Valve Actuator Characteristics

20. Key Elements to Valve Actuators The key elements to consider when selecting an actuator/control valve combination include: • Type of service-on/off or throttling • Power source-air, electric, or other • Loop stability requirements • Input signal compatibility • Actuator thrust requirements • Size and weight considerations • Safety requirements (e.g. fail-safe operation, area classification, etc.) • Operating environment-heat, vibration, corrosion. etc. • Dead band and hysteresis factors • Use of accessories (e.g., positioners, micro switches, handwheels, microprocessors, etc.); • Ease of maintenance • Economic factors-first cost, maintenance costs, and life-cycle costs.