Hello,

I have side by side API pumps with nozzle load factor of 1 for a pipeline project. 10” 600# ball type MOVs are installed on straight horizontal suction and discharge lines perpendicular to the pump axis. Operating temp is 20 deg C and install temp is -29 deg C. Considering the temp range, there is enough flexibility and nozzle loads are ok except one in the Y direction (API definition – nozzle projection direction.) Due to the heavy weight of the valve, the friction forces (factor =0.4) on valve supports cause over load on the nozzle (about 2.2 times allowable.) There are 1/2“ Uniroyal rubber pads between the valves and chunk saddle supports by client requirement.

As far as I know the rubber undergoes a greater shear deflection than compression and the deflection at the supports is just 2 mm. If the rubber is quite flexible in shear deflection, the friction force would be ignored (not requiring a sliding pad like Teflon.) With the friction ignored, nozzle load in the direction is 0.5 allowable (Table 4).

Do you have any comment or advice on this approach?

Many thanks in advance.