一、进口双作用气动执行器概述

双作用气动执行器就是通气的情况下气动执行器就开始转动打开阀门，当要关闭阀门的时候另外一边通气才能关闭，是靠气缸复位的，在失去气源的时候只能保持原位。

A double acting pneumatic actuator starts to rotate and open the valve when it is ventilated. When the valve needs to be closed, the other side of the actuator can only close when it is ventilated. It is reset by the cylinder and can only remain in place when the air source is lost.

二、双作用式气动执行器工作原理

当气源压力从气口（2）进入气缸两活塞之间中腔时，使两活塞分离向气缸两端方向移动，两端气腔的空气通过气口（4）排出，同时使两活塞齿条同步带动输出轴（齿轮）逆时针方向旋转。反之气源压力从气口（4）进入气缸两端气腔时，使两活塞向气缸中间方向移动，中间气腔的空气通过气口（2）排出，同时使两活塞齿条同步带动输出轴（齿轮）顺时针方向旋转。（如果把活塞相对反方向安装，输出轴即变为反向旋转）

When the air source pressure enters the middle chamber between the two pistons of the cylinder from the air port (2), the two pistons are separated and move towards both ends of the cylinder. The air in the two air chambers is discharged through the air port (4), and the two piston racks are synchronized to drive the output shaft (gear) to rotate counterclockwise. On the contrary, when the air source pressure enters the air chambers at both ends of the cylinder from the air port (4), the two pistons move towards the middle direction of the cylinder, and the air in the middle chamber is discharged through the air port (2). At the same time, the two piston racks synchronously drive the output shaft (gear) to rotate clockwise. (If the piston is installed in the opposite direction, the output shaft will rotate in the opposite direction.)

三、双作用式气动执行器选用

选用气动执行器时，在已确定阀门的扭矩上再增加安全值，水蒸气或非润滑的液体介质增加25%安全值；非润滑的浆料液体介质增加30%安全值；非润滑的干气介质增加40%安全值；非润滑用气体输送的颗粒粉料介质增加60%安全值；对于清洁、低摩擦的润滑介质增加20%安全值（上述安全值为本公司理论推荐，仅供参考）。

双作用式执行器选用示例

当控制一个需要扭矩200Nm的球阀，气源压力只有0.5MPa，介质为非润滑的水蒸气，考虑到安全因素，增加25%安全值等于250Nm，按双作用输出扭矩表查找气源压力0.5MPa，然后沿该列垂直查找等于或相近的扭矩数据，选268Nm，再沿该行向左查找其型号，选择V-AT125型。

When selecting pneumatic actuators, increase the safety value by 25% on the determined valve torque, and increase the safety value by 25% on water vapor or non lubricated liquid media; Non lubricating slurry liquid medium increases the safety value by 30%; Non lubricating dry gas medium increases safety value by 40%; The particle powder medium transported by non lubricating gas increases the safety value by 60%; For clean and low friction lubricating media, increase the safety value by 20% (the above safety values are theoretical recommendations of our company and are for reference only).

Example of selecting a double acting actuator

When controlling a ball valve that requires a torque of 200Nm, the air supply pressure is only 0.5MPa, and the medium is non lubricating water vapor. Considering safety factors, increasing the safety value by 25% is equal to 250Nm. Use the double acting output torque table to search for the air supply pressure of 0.5MPa, then vertically search for torque data equal to or close to this column, select 268Nm, and then search left along this row for its model, selecting V-AT125 type.

四、双作用式气动执行器性能参数

四、气动执行器有关数据

A）执行器的动作时间是下列条件测试；（1）常温（2）900行程（3）电磁阀4mm口径，流量为Qn400L/min   （4）管子内径8mm（5）中性干净空气（6）气源压力0.6MPa（7）执行器空载

注：在现场测试中一个或多个参数不同，动作时间会发生变化。

B）单作用重量为10根弹簧计算；需要增加或减少弹簧数量按每根弹簧重量来计算增加或减少每一台重量。