Vane actuator

Hydraulic and pneumatic vane actuators provide a direct translation from the vane to a partial turn actuator output without the additional conversion mechanism required for a diaphragm or piston actuator. 

Vane—Vane actuators direct air against paddles or vanes. 

The development of positive displacement downhole motors began in the late 1950s. The initial development was the result of a United States patent filed by W. Clark in 1957. This downhole motor was based on the original work of a French engineer, Rene Monineau, and is classified as a helimotor. The motor is actuated by drilling mud pumped from the surface. There are two other types of positive displacement motors that have been used, or are at present in use today the vane motor and the reciprocating motor. However, by far the most widely used positive displacement motor is the helimotor [79,83]. 

There have been some efforts over the past three decades to develop positive development vane motors and reciprocating motors for operation with drilling mud as the actuating fluid. These efforts have not been successful. 

Fluid motors are usually classified according to the type of internal element which is directly actuated by the pressurized flow. The most common types of elements are gears, vanes and pistons. All three of these types are... 

Turbine A rotary device that is actuated by the impact of a moving fluid or gas against blades or vanes. 

Friction and the changing mechanical advantage of these motion conversion mechanisms mean the available torque may vary greatly with travel. One notable exception is vane-style rotary actuators whose offset piston pivots, giving direct rotary output. 

An alternative approach to achieving patient coordination between actuation and inhalation is a breath actuated device such as the Autohaler. This device uses a mechanical vane to detect the appropriate inhalation rate for automatic firing of the pMDI. 

Figure 7 The Aerolin Autohaler. Arrows indicate the direction of movement of the catch and vane. The lever at the top of the device has been pushed into an upright position, thus compressing the spring. When the patient inhales, the vane moves, allowing the compressed spring to force the MDI downward and the valve to actuate. (From Ref. 69.)...

Elevation of the priming lever compresses a spring above the base of the MDI. A mechanical obstruction prevents movement of the aerosol canister within the plastic moulding until the patient inhales. Inhalation rotates a small vane within the mouthpiece, removing the obstacle and allowing the aerosol canister to move down sufficiently to actuate the MDI. Unscrewing the removable sleeve can open the Autohaler. This allows the MDI to be removed and the mouthpiece adapter to be washed (68). 

Valves. Valves control the way the gas is used, stopped, or directed. They must function under a variety and range of temperatures. Control or proportional valves in a process system are power-operated mechanisms able to alter fluid flow. A pneumatic valve actuator adjusts valve position by making the air pressure either linear or rotary motion. Ball valves provide the shutoff capability. Gas valves are specialized to control the flow of another medium, such as natural gas. A pressure relief valve is a self-actuated safety valve that relieves pressure. A butterfly valve controls the flow of air or a gas through a circular disk or vane by turning the valve s pivot axis at right angles to the directing flow in the pipe. 

Solid-state actuation signifies the use of the induced-strain effect present in active materials to achieve actuation without any moving parts, i.e., in a solid-state manner. Already, solid-state actuation has found niche application in the aerospace industry. The aero-servo-elastic control of vibrations and flutter with solid-state actuated flaps, tabs, vanes, etc. for helicopter rotor blades and aircraft wings is currently being experimented on. 

Pneumatically (air) operated—This is the most common type of actuator. Pneumatic actuators convert air pressure to mechanical energy and can be found in three designs (1) diaphragm, (2) piston, and (3) vane. 

Actuators for control valves come in three basic designs pneumatic, electric, and hydraulic. Pneumatic actuators, which convert air pressure to mechanical energy, use three designs diaphragm, piston, and vane. Electrically operated actuators convert electricity to mechanical energy. Common examples include solenoid valves and motor-driven actuators. Hydraulically operated actuators convert liquid pressure to mechanical energy. The hydraulic actuator uses a liquid-tight cylinder and piston to move or position the valve stem. 

The operation of a control valve involves an air supply that positions its movable part (i.e. plug, ball, or vane) relative to the stationary seat of the valve. A valve actuator accurately locates the valve plug in a position determined by the pneumatic control signal and operates to move the valve to either fully open or fully closed positions. The actuators may be either piston or diaphragm types. Air-to-open valves require air to open and therefore automatically close in the event of fail closure. They are therefore used on fuel lines to furnaces. Air-to-close valves fail to open on a loss of air pressure and are used on air lines into fuel burners. In general, fail-to-open and fail-to-close valves operate when the supplied air pressure drops below a minimum value. 

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