How to calculate valve torque

For rotary valves, the factors involved include the friction between the valve stem and the packing, the friction between the butterfly disc (or ball) and the valve seat, as well as the thrust exerted on the valve core by the pressure in the pipeline; all of these are related to the friction coefficient of the materials used. . .

I posted about this issue before, but no one managed to solve it

Typically, valve manufacturers provide torque data. Calculating it is quite complex; the main factors involved are the friction between the valve disc and the seat, the friction between the valve shaft and the packing, as well as the thrust exerted on the valve disc due to pressure differences with varying media. What’s important is that there are so many types of valve plates, valve seats, and packings; each one has a different level of friction, as well as variations in the size of the contact surfaces and the degree of compression. So, in general, measurements are taken using instruments rather than calculations.

At present, for torque testing, it is estimated that there are no testing instruments such as hardness testers or spectrometers available; the mechanical principles involved require equipment that goes beyond what ordinary small-scale instruments can provide. Therefore, it is relatively difficult to carry out convenient testing. This is just my opinion; please feel free to correct me!

If you want to get a rough estimate, try using a torque wrench

This post was last edited by pzhmotor on 2009-8-7 20:42. It seems to be directly related to the pressure inside the pipeline. Theoretical calculations are quite difficult; it is estimated that the method involves converting pressure multiplied by area into force, and then calculating torque using the lever arm. Frictional resistance also needs to be added in the middle. The poster is probably looking to choose an actuator for an electric or pneumatic valve. Based on actual testing, using a torque wrench on the 6th floor might indeed be a good solution. However, control valves come with specific pressure ratings; by noting the properties of the fluid and the temperature parameters, and by consulting the valve manufacturer, they can help you select the appropriate valve. There are specialized instruments for measuring torque; they are available at the Steel Research Institute, and I have seen examples of measuring the rolling mill drive shafts under load. It should not be suitable for measuring valve torque.

When designing valves, the actuator to be used is selected through estimation, which generally involves three components: the frictional torque due to the seals (between the ball and the valve seat), the frictional torque exerted by the packing on the valve stem, and the frictional torque exerted by the bearings on the valve stem. The calculated pressure is generally taken as 0.6 times the nominal pressure (approximately the operating pressure), while the friction coefficient is determined based on the material. The calculated torque is multiplied by 1.3 to 1.5 to select the actuator.

8# lys11803 Does anyone know how to calculate the torque for Borgman check valves? The definition of torque is the product of force and distance

Personally, I think experiments speak louder than words; the calculated values differ greatly from the actual ones

Isn’t a torque wrench usually used?