Question: What is the method of torque calculation for high temperature and high pressure forged steel ball valves?
Answer: The torque of high temperature and high pressure forged steel valve is an important parameter of the valve; so many friends are very concerned about the problem of valve torque calculation. Fan Valve introduces the formula for calculating the torque of Fan Valve in detail
The specific torque calculation of high temperature and high pressure forged steel ball valve is: the square of one-half of the valve diameter × 3.14 is the area of the valve plate, and then multiplying it by the bearing pressure (that is, the valve working pressure) to obtain the static pressure on the shaft, multiplying Take the friction coefficient (to check the table, the friction coefficient of general steel is 0.1, and the friction coefficient of steel to rubber is 0.15), multiply the shaft diameter and divide by 1000 to get the torque of the valve, the unit is N•m, electric device and pneumatic actuator The reference safety value of the device is 1.5 times the valve torque.
When the valve is designed, the selection of actuator is based on estimation, which is basically divided into three parts:
1. The friction torque of the seal (ball and valve seat)
2. The friction torque of the packing to the valve stem
3. The friction torque of the bearing to the valve stem
Therefore, the calculated pressure is generally 0.6 times the nominal pressure (approximately working pressure), and the friction coefficient is determined according to the material. Multiply the calculated torque by 1.3~1.5 times to select the actuator.
Valve torque calculation should take into account the friction between the valve plate and the valve seat, the friction between the valve shaft and the packing, and the thrust of the valve plate under different pressure differences of the medium.
Because there are too many types of valve plates, valve seats and packing, each has different friction, as well as the size of the contact surface, the degree of compression, and so on. Therefore, it is generally measured by meter instead of calculation.
The calculated value of valve torque has great reference significance, but it cannot be copied completely. Under the influence of many factors, the valve torque calculation is not more accurate than the experimental results.