The Low Down On Pump Intake Isolation Valves

500HPU3One of our members wrote me with this question:

“I’d like to hear your opinion about isolation valves on pump intake lines. Within our company there is an ongoing debate over whether we should use a more expensive ball valve or a cheaper butterfly valve?”

At the root of this question is the negative effect of turbulence in the pump intake line. The argument for using a ball valve as an intake line isolation valve is, when it’s open, the full bore of the valve is available for oil flow. So if you have a 2″ ball valve in a … continue reading »

How To Tie Up A Supertanker With Teflon Tape

Not an ideal pump mounting positionOld hands know this, but I am often asked why Teflon tape should NOT be used on tapered-thread hydraulic adaptors. Here, one of our members explains why:

“I had a big handful of trouble on a ship because incompetent yard mechanics (they are abundant!) used Teflon tape to seal connections. The tape got into the check valve of the control block of a spring-return valve actuator, making it creep into the non-tensioned position. Everything can be solved, but this problem cost us large sums because we only had few hours to find the fault, and long periods of impatient waiting continue reading »

What To Check BEFORE You Change Your Hydraulic Oil

hydraulic oil drumThe issues which can arise when switching brand and/or type of hydraulic oil, is a question I get a lot. And the crux of this problem, is:
1.    You can never completely drain ALL of the original out of the hydraulic system; and therefore:
2.    There WILL be some mixing of the original and the new oil, so how do you make sure they are miscible (compatible)?

Oil additive makers and oil blenders face the very same issue when they want to run field trials to compare the performance of their latest creation with an existing ‘control’ fluid. And the … continue reading »