Just a quick note, as we have been experiencing similar problems with these bearing isolators for some time. Originally we had VBX but when problem persisted that went to VBXX and we are now at VBXXD's ! Believe it or not there is another version about to be released.
The length of the isolator...
I think you will find that most companies are similar, in that controlling flow rates tends to be determined by a flow control valve and not by variable speed. This is 'old' technology. In essence, the pump generates too much head for the required flow and the FCV then has to limit the flow. The...