2、 Operating principle of pneumatic actuator:
1. When the compressed air enters the pneumatic actuator from nozzle A, the gas pushes the double pistons to move in a straight line towards both ends (cylinder head end). The rack on the piston drives the gear on the rotating shaft to rotate 90 degrees counterclockwise, and the valve is opened. At this time, the gas at both ends of the pneumatic actuator valve is discharged with nozzle B. On the contrary, when the compressed air enters both ends of the pneumatic actuator from the nozzle B, the gas pushes the double plug to move in a straight line in the middle. The rack on the piston drives the gear on the rotating shaft to rotate 90 degrees clockwise, and the valve is closed. At this time, the gas in the middle of the pneumatic actuator is discharged with nozzle A. The above is the transmission principle of the standard type. According to the user's needs, the pneumatic actuator can be installed in the opposite transmission principle to the standard type, that is, the valve is opened when the alignment shaft rotates clockwise, and closed when it rotates counterclockwise. Single acting (spring return type) pneumatic actuator nozzle A is the air inlet, nozzle B is the exhaust hole (nozzle B should be equipped with a muffler). The air inlet of nozzle A is to open the valve, and the valve is closed by spring force when the air is cut off.
2. The single action here means that the cylinder is reset with a spring. When gas failure or power failure occurs, the valve is reset by the spring in the cylinder to close or open the valve. (Normally closed or normally open optional). Double acting means that the cylinder is opened and closed by compressed air.

Band of non-metallic compensator and its device in circulating fluidized bed boiler
The belt of non-metallic compensator is mainly processed with glass fiber cloth and glass fiber coated rubber cloth or fluoroplastic cloth as the main materials. The belt surface of flexible fabric compensator (non-metallic compensator) is mainly used to receive the pressure of flue gas system and chemical corrosion from flue gas or outside. The belt surface must be soft to absorb displacement from all directions.
The outer layer is usually coated with glass fiber cloth for silicone rubber with good weather resistance, and can also be coated with fluororubber, PVC and EPDM. It can decide whether to make another insulation layer according to the temperature of the system. The compensator is also known as the contraction joint, which is used to apply the effective expansion deformation of the elastic element of the compensator to absorb the pipeline
The utility model relates to a compensation installation for the size change of a conduit or a container caused by thermal expansion, cold contraction and other reasons, belonging to a compensation element. It can absorb axial, transverse, and angular displacement, and is used to absorb vibration and reduce noise when heating displacement and mechanical displacement of pipes, equipment and systems.