A simple tool to calculate sliding bearing dimensions for trunnion mounted ball valve.

Failing to calculate the correct dimensions of the bearing when you design your ball valves may lead to have to much pressure on a small portion of the bearing itself while the valve is operating at max pressure, and this can lead to an increase of the system torque or even to the failure of the bearing itself.

Thanks to our internal test bench we were able to gather all the data needed in order to produce a quite simple equation you can use to calculate the correct size you need.

SIMPLIFIED SIZING FOR RADIAL SLIDING BEARINGS

For a simplified calculation we consider the projection between the internal diameter and the length of the bearing in order to find the contact area where pressure will be exerted. Obviously this type of calculation is very simplified, in fact you will have to correct the result of this area with a correction factor that varies according to the bearing diameter (at the end of the article you will find the chart according to the bearing Type)

Bearing sizing calculation is carried out so that the specific pressure does not exceed the applicable load value, see tables below depending on the type of bearing and the conditions of use.

HERE IS THE EQUATION:

GIVEN:

p Pressure on the bearing (N/ mm2)

F Applied load (N)

D Internal diameter of the bearing (mm)

L Lenght of the bearing (mm)

Fc Correction factor of the bearing size (See table below)

Pam Admissible pressure according to the conditions of use (see maximum recommended value in Tables)

For detaliled information on TX - TF - PMT type bearings, please visit our website at the following link.

Have a good day,

Michele.