Orifice Plug

In this situation, the orifice plug limits the output flow from the pump. This keeps it from running too far to the right on the standard curve, where cavitation could become likely. It is sometimes called a "Q-max" orifice.

(There may also by a bypass with a "Q-min" orifice to ensure enough flow to keep the pump from running too far to the left.)

Thanks Tornado for your reply...The orifice plug is installed at each column of shaft where sleeve bearing ( 2 set) is also installed. The pump is installed in MDEA Solution sump tank and the diameter of orifice is only 2. Maybe it is for lubrication or something as VS2 is the discharge is through column...Can you help me clarify...Many Thanks...Godbless...Peace

This terminology is confusing. Originally, I thought you were describing orifices in the piping for the pumped fluid. Now it sounds like orifices in a lubricating system for the drive shaft and/or bearings, for which 2mm diameter makes sense.

I don't know why, but drawings often seem to be "grayed out" on CR4; and often too small to see, with no easy zooming facility. You are not alone in being stymied over this.