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Valve torque calculation description

What is the method of valve torque calculation? Valve torque is an important parameter of the valve, so many friends are very concerned about the problem of valve torque calculation. Below, Kun Hui Fluid explains valve torque calculation in detail.
The valve torque calculation is specifically: one-half of the valve diameter × 3.14 is the area of the valve plate, multiplied by the bearing pressure (that is, the valve working pressure) to obtain the static pressure on the shaft, multiplied by the coefficient of friction ( To check the table, the general steel friction coefficient is taken as 0.1, and the steel-rubber friction coefficient is taken as 0.15), multiplied by the shaft diameter divided by 1000 to obtain the torque of the valve, and the unit is cow-meter. The reference safety value of the electric device and the pneumatic actuator Take 1.5 times the valve torque.
When the valve is designed, the actuator is selected by estimation and basically divided into three parts:
1. Friction moments seen in seals (ball and seat)
2. Friction torque of packing on valve stem
3, the bearing on the valve stem friction torque
Therefore, the calculated pressure is generally taken as 0.6 times the nominal pressure (about the working pressure), and the friction coefficient is determined according to the material. Calculate the torque multiplied by 1.3 to 1.5 times to select the actuator.
The calculation of the valve torque must 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 against the differential pressure of the medium.
Because there are too many types of valve plates, seats, and packings, each has different frictional forces, as well as the size of the contact surface, the degree of compression, and so on. Therefore, it is generally measured by the instrument rather than calculated.
The calculated value of the valve torque is of great significance, but it cannot be completely copied. Under the influence of many factors, the valve torque calculation has not been more accurate than the experimental results.
Glossary: Torque
Torque is the force that rotates an object. The engine torque refers to the torque output from the crankshaft side of the engine. In the condition of fixed power, it is inversely proportional to the engine speed. The faster the speed, the smaller the torque, and vice versa, it reflects the load capacity of the car within a certain range.
Valve Torque Calculation: 1′′-600LB Stem Torque Calculation (1) Total Valve Stem Torque MF = MQF + MFT (2) Ball and Seat Friction Moment MQF MQC = MQF1 + MQF2 MQF1 Seat Friction Due to Ball Preload Torque MQF1=0.3925(D2JH-D2MN)*(1+COSθ)*qM*fM*R MQF2 Frictional moment due to medium working pressure MQF2=π*P* fM*R(D2JH-0.5 D2MN-0.5 D2MW)(1+ COSθ)/8COSθ
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Calculation result: MQF1 = 9043 Nmm MQF2 = 63192Nmm MQF = 72235 Nmm (3) Friction torque between packing and valve stem MFT MFT=0.5*FT*dF FT=ψ*dF*bT*P
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Calculation result: MFL=5840 Nmm Calculation result: MF=78075 Nmm

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