Butterfly valve selection rules introduction

Butterfly valve selection rules;

Stem diameter: For multi-turn type open rod valves. It cannot be assembled into an electric valve. Therefore, if the electric butterfly valve device allows the diameter of the large stem to pass through the valve stem of the valve being fitted. The inner diameter of the hollow shaft of the electric device must be larger than the outer diameter of the stem of the open rod valve. For the partial rotary valve and the dark rod valve in the multi-turn valve, although the problem of the diameter of the stem is not considered, the diameter of the stem and the size of the keyway should be fully considered in the selection, so that the assembly can work normally.
Operating torque: The operating torque is the main parameter for selecting the valve's electric device. The motion of the electric butterfly valve can be controlled by the stroke, torque or axial thrust. Since the working characteristics and utilization rate of the valve electric device depend on the type of valve, the working specification of the device and the position of the valve on the pipeline or equipment, the valve electric butterfly valve device is an indispensable device for realizing valve program control, automatic control and remote control. Therefore, the correct selection of the valve electric device is essential to prevent the occurrence of overload (operating torque is higher than the control torque). Usually, the basis for the valve electric butterfly valve device is correctly selected.
The output torque of the electric device should be 1.2-1.5 times of the valve operation * large torque.
Electric butterfly valve operation thrust: There are two kinds of main structure of the valve electric device: one is not equipped with a thrust plate. The output torque is converted to output thrust by the stem nut in the thrust disk. Direct output torque; the other is to configure the thrust plate.
Number of rotations of the output shaft: The number of rotations of the output shaft of the valve electric device is related to the nominal diameter of the valve, the pitch of the valve stem, and the number of threads. H is the valve opening height, which is calculated according to M=HZS (M is the total number of revolutions that the electric device should meet. S is the stem drive thread pitch, and Z is the stem thread number.