Independently developed ND/NQ series pneumatic valve actuators, with reasonable structure, modular design, high performance, high stability, large output torque, long service life, beautiful appearance, suitable for supporting ball valves, butterfly valves, plug valves and other standards VDIIVDE3845, with NAMUR standard groove, can install all control accessories, Such as limit switches, electrical positioners, position sensors, etc.

Output shaft holes and connection flanges conform to IS05211.

Actuator according to its energy form is divided into pneumatic, electric and hydraulic three categories, they have their own characteristics, suitable for different occasions. Pneumatic actuator is a kind of actuator. Pneumatic actuators can also be divided into single-acting and double-acting types: the switching actions of the actuators are driven by the air source and are called DOUBLE ACTING. SPRING RETURN (single action) only on action is air driven, while off action is SPRING reset.

The purpose of this reference is to help the customer make the correct choice of the actuator. The following factors must be considered before installing the pneumatic/electric actuator into the valve. * Valve operating torque plus manufacturer's recommended safety factor/according to operating conditions. * Air source pressure or power supply voltage of the actuator. * Type of actuator double acting or single acting (spring return) and output torque under certain air source or output torque under rated voltage. The correct choice of an actuator is very important. If the actuator is too large, the stem may be overloaded. Conversely, if the actuator is too small, the side cannot generate enough torque to fully operate the valve. In general, we think that the torque required to operate a valve comes from friction between the metal parts of the valve (ball core, disc) and the seal (seat). Depending on the valve service, service temperature, operating frequency, piping and differential pressure, flow media (lubrication, drying, mud), many factors can affect operating torque

The structural principle of the ball valve is basically based on a polished ball core (including the channel) sandwicked between the two seats (upstream and downstream), the rotation of the ball center intercepts or flows through the ball core, and the force generated by the pressure difference between upstream and downstream makes the ball core close to the downstream seat (floating ball structure). The torque for operating the valve in this case is determined by the friction between the ball core and the seat and the stem and the packing. As shown in Figure 1, the maximum torque occurs when the pressure difference occurs and the ball core rotates towards the open direction in the closed position

Butterfly valve. The structure principle of butterfly valve is basically based on the butterfly plate fixed on the axis. Disc is fully sealed with seat in closed position and valve is in full open position when disc is rotated (around stem) parallel to flow direction. Conversely, when the disc is perpendicular to the flow direction of the fluid, the valve is in the closed position. The torque of operating butterfly valve is determined by the friction between butterfly plate and seat, stem and packing, and the force of differential pressure on butterfly plate also affects the operating torque, such as the maximum torque when the valve is closed, and the torque will be significantly reduced after a small rotation

The structure of the plug valve is based on the plug sealed in a conical plug. There is a passage in one direction of the plug. The valve is opened and closed as the plug is screwed into the seat. Operating torque is usually not affected by fluid pressure but is determined by friction between the seat and plug during opening and closing. Valve maximum torque when closed. Due to pressure, always maintain high torque for the rest of the operation.