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Actuators

Valve actuators are selected considering several factors including torque, necessary to let the valve work and an automatic operation.

Types of actuators include manual handwheel, manual lever, electrical motor pneumatic, solenoid, hydraulic piston, and self-actuated. All actuators, except for manual hand wheel and lever, are adaptable to automatic actuation. Valve actuators are selected considering several factors including torque, necessary to let the valve work and an automatic operation.
Types of actuators include manual handwheel, manual lever, electrical motor pneumatic, solenoid, hydraulic piston, and self-actuated. All actuators, except for manual hand wheel and lever, are adaptable to automatic actuation.

The actuators are designed based on the torque of the valves, the function which it will be used or particular requests from the costumer.

Manual actuators allow the valve to be placed in any position, but do not permit automatic operation.  The most common type mechanical actuator is the handwheel. This type includes handwheels fixed to the stem, hammer handwheels, and handwheels connected to the stem through gears. Handwheels fixed to the stem claim a wheel as the only the mechanical advantage. But these valves are exposed to high operating temperatures. This characteristic makes operations difficult. The hammer hand wheel rounds freely partially and then it hits against a lug on a secondary wheel. The secondary wheel is connected to the valve stem.

If additional mechanical advantage is necessary for a manually-operated valve, the valve bonnet is
fitted with manually-operated gear heads. A special wrench or hand wheel connected to the pinion shaft, allows only one person to make the valve work. Since several rounds of the pinion are necessary to produce one entire turn of the valve stem, the operating time of large valves is exceptionally long. The use of portable air motors connected to the pinion shaft reduces the valve operating time.

Electric motors permit manual, semi-automatic, and automatic operation of the valve. Motors are used mostly for open-close functions, although they are adaptable to position the valve to any point. The motor is usually a reversible, high speed type, connected through a gear train to reduce the motor speed and thereby increase the torque at the stem.

 Direction of motor rotation determines direction of disc motion. 
The electrical actuation can be semi automatic when the motor is activated by a control system. A handwheel, which can be used with the gear train, is provided for manual operating valves. Limit switches are normally used to stop the motor automatically at full open and full closed valve positions. Limit switches operate either physically by position of the valve or by torque of the motor.

Pneumatic actuators are provided for automatic or semiautomatic valve operations. These actuators translate an air signal into valve stem motion by air pressure acting on a diaphragm or by a piston connected to the stem. Pneumatic actuators are used for open-close position where fast action is required. Duplex actuators have air supplied to both sides of the diaphragm. The differential pressure across the diaphragm position the valve stem. Automatic operation is provided when the air signals are automatically controlled by circuitry. Semi-automatic operation is provided by manual switches present in the circuitry.

Hydraulic actuators provided for semi-automatic or automatic position of the valve, similar to the pneumatic actuators. These actuators use a piston to convert a signal pressure into valve stem motion. Hydraulic fluids go inside one side of the piston while on the other side they are drained. Water or oil are used as hydraulic fluid. Manual valves can be used for controlling the hydraulic fluid, too; this way, semi-automatic operation is provided.

Solenoid actuators have a magnetic slug connected to the valve stem. The force to place the valve comes from the magnetic attraction between the slug on the valve stem and the coil of the electromagnet in the valve actuator.

Control Panel

Control panels provide a way to control in a reliable way both pneumatic and hydraulic ball, butterfly and plug valves. Our control panels use the highest quality components for extended dependability, they also provide an adjustable operating time in excess of critical surge period.

The electrical panels provide remote monitoring of the valve, pump operation and the conditions of the alarm.

Our control panels are designed for air, oil, water use and systems. They can be provided with junction boxes for the customer’s connections and with an optional hand control valve to be used with no electrical power conditions.

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