Actuator of the hottest pneumatic film

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Pneumatic diaphragm actuator

www.mechnet com. cn "> actuator of pneumatic diaphragm:

1. Actuator: it is a device that converts the output signal of the controller into the linear displacement of the control valve stem or the angular displacement of the valve shaft. The actuator provides driving force or driving torque to overcome the unbalanced force, valve pressing force and friction, so that the displacement changes in proportion to the input signal.

2. Pneumatic diaphragm actuator: pneumatic diaphragm actuator is the most commonly used actuator. Pneumatic diaphragm actuator Membrane actuator is widely used because of its simple structure, reliable action, convenient maintenance and low cost. It is divided into two execution modes: positive action and reaction. When the input signal of the positive action actuator increases, the displacement of the push rod is outward; When the input signal of the reaction actuator increases, the displacement of the push rod is inward

3. When the input signal increases, a thrust is generated on the membrane membrane. After overcoming the force of the spring, the push rod displaces and the displacement direction is outward. Therefore, it is called positive action actuator. On the contrary, the input signal connection port is on the lower diaphragm cover. When the signal increases, the push rod displacement inward and retracts into the diaphragm box, which is called the reaction actuator

4. The characteristics of pneumatic thin film actuator are as follows:

1) the positive and reaction actuator should speed up the research and development of advanced melting, solidification molding, vapor deposition, profile processing, efficient synthesis and other new material preparation key technologies and equipment, which are basically the same in structure, and are composed of upper membrane cover, lower membrane cover, thin film diaphragm, push rod, spring, adjusting parts, support and stroke display board

2) the main difference between the structure of the positive and reaction actuator is that the workbench and the upper beam are connected through two columns. The input signal of the reaction actuator is at the lower part of the capsule, and the lead out push rod is also at the lower part. Therefore, the lead out of the valve rod should be sealed with a sealing sleeve, while the input signal of the positive action actuator is at the upper part of the capsule, and the lead out of the push rod is at the lower part of the capsule. Due to the good sealing of the membrane, Sealing is not required at the stem outlet

3) the initial force of the spring can be changed through the adjustment of the adjusting element, so as to change the thrust of the actuator

4) the input and output characteristics of the actuator show a linear relationship, that is, there is a linear relationship between the output displacement and the input signal pressure. The output displacement is called stroke and is displayed by the stroke display panel. Some reaction actuators also install a valve position display on the upper part of the capsule to display the valve position. The stroke of domestic pneumatic diaphragm actuator has six specifications, including lomm, 16mm, 25mm, 40mm, 60mm and lOOmm

5) the effective area of the diaphragm of the actuator is directly proportional to the thrust. The larger the effective area is, the greater the thrust of the actuator is

6) a displacement conversion device can be added to convert linear displacement into angular displacement for rotating the valve body

7) valve positioner can be added to realize valve position detection and feedback and improve the performance of control valve

8) a handwheel mechanism can be added, and the handwheel can be used for degradation operation in case of automatic control failure, so as to improve the reliability of the system

9) a self-locking device can be added to realize the self-locking and position keeping of the control valve. The fine and small pneumatic diaphragm actuator has made important improvements in the mechanism. It uses multiple springs to replace the original spring, which reduces the height and weight of the actuator. It has the advantages of compact structure, energy saving, large output thrust and so on. Compared with the traditional pneumatic diaphragm actuator, the height and weight can be reduced by about 30%. It is the schematic diagram of a fine and small pneumatic diaphragm actuator with four spring structures. Side mounted pneumatic diaphragm actuator, also known as force increasing actuator, is also known as Σ F series actuator abroad. It uses a force increasing device to convert the horizontal thrust of the pneumatic diaphragm actuator into the vertical thrust through the amplification of the lever. Because the connection relationship of the parts can be easily changed on the force increasing device to replace the positive and negative reaction mode, and we have the courage to seek excellent variable magnification. For example, the magnification of the force increasing device can reach 5.2, and domestic products can also reach 3. Therefore, it is favored by users

5. Advantages of rolling diaphragm actuator: using rolling diaphragm, the displacement under the same effective area is large, and compared with the piston actuator, it has the characteristics of low friction and good sealing. It is usually used with eccentric rotary valve

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