Manual gearbox selection
1. Confirm the torque of the valve, add the coefficient (generally *1.3 or 1.5), and select the gearbox model with greater than this torque.
2. Check the information
A. Whether the diameter of the valve stem exceeds the allowable size of the gearbox, if it exceeds, select the gearbox model according to the diameter of the valve stem.If it is a rising stem valve, determine the thread standard and size.If it is a keyway connection, determine the number, size and position of the keyway.
B. If the connection dimensions of the valve and the gearbox are inconsistent, the manufacturers of the two parties will negotiate a solution to achieve matching production.Now commonly used is the international ISO5211/5210 standard.
3. Other special factors: housing material selection, lubricating oil temperature selection, protection level, opening direction (conventional counterclockwise opening), paint color, protective cover size, packaging requirements, etc.
 
Electric gearbox selection
1. We have selected the appropriate gearbox based on the valve torque and stem diameter. According to the efficiency and speed ratio of the gearbox, the required input torque, that is, the output torque of Denso, can be calculated to select Denso.
2. Sometimes, the valve and Denso have been determined, and it is necessary to select a suitable gearbox for transition.The gearbox model is still selected according to the valve, and then the required speed ratio of the gearbox is calculated according to the valve torque, electrical torque, and gearbox efficiency.Actual production is based on this speed ratio (generally, the speed ratio of a single-stage gearbox cannot be changed, but a two-stage gearbox can).
3. Calculate the valve opening and closing time based on the speed, speed ratio, and number of revolutions, and it should not exceed 15 minutes.
There is also a simpler way to provide the valve and denso information to the gearbox manufacturer, let the engineer choose the model, and choose the appropriate and economical model for you.