August 7, 2007 

'Inside Hydraulics' Newsletter

1. Dynamic online monitoring of oil
2. Strange but true ...
3. How to synchronize hydraulic cylinders
4. Content for your web site or e-zine
5. Help us spread the word
6. Tell us what you think


Dynamic online monitoring of oil

Water contamination in fuel or oil can cause a host of problems such as fuel loss, additive depletion, oil oxidation, corrosion, reduced lubricating film thickness, accelerated component wear rates, microbiological growth, reduction in dielectric strength and loss of power. These problems can be detected and ultimately avoided by online monitoring of water content.

If water ingression poses a threat to your equipment, EESIFLO's solution is its EASZ-1 online water in oil monitor. Available in sizes from 1 to 48 inch with NPT or BSP threads or flanges to DIN/ANSI or JIS. The unit has been designed to work in hostile environments and has an all 316 stainless steel construction with an IP66 rated transmitter housing. The unit runs on loop power and internationally approved Atex or IECEx versions can be supplied for hazardous environments.

EESIFLO's EASZ-1 water in oil analyzer

The EASZ-1 Water in oil monitor.

The EASZ-1 water sensor is a quick ship item and is available worldwide. For more information, please locate your local EESIFLO dealer at

The Nice Things People Say

"Brendan, I am excited. I just downloaded your and Marian's writings on Variable Pump Control and Electro-Hydraulic Control Systems they are extremely well thought out with easy to understand terminology. Well done and thanks for making them available at a realistic price."

Kevin McCaffrey
Excel Hydraulics
Sydney Australia

2.   Strange but true ...

A few months ago, I was involved - in a supervisory capacity - in the planned change out of components on a hydraulic machine.

The design of the machine's hydraulic power unit was the all-too-common, cheap and nasty, everything mounted on the tank lid variety. You know the ones - electric motors mounted vertically, with pumps submerged in the tank. They're cheap and easy to build, but an eternal pain in the butt for anyone who has to work on them. I could rant about this but I'll save it for another day.

The scope of work included changing out a tandem gear pump submerged in the tank. On this machine, a 15 minute job - after you've spent two hours disconnecting everything to enable the tank lid to be lifted.

I was offsite when this pump was changed, but the technician doing the work was experienced and knew what had to be done. After the shut down was completed, the same technician was scheduled to re-commission the machine. But due to conflicting commitments he became unavailable.

It was early in the afternoon when I got the call requesting I go to site to supervise start-up. Thinking this would be a case of push the button and watch everything behave as it should, I left the office in my 'civilian' clothes, took my good car and no tools. BAD mistake.

Commissioning didn't begin well. The rear section of the tandem gear pump that had been replaced, charged an accumulator. But we weren't getting any charge pressure on start-up. The direction of rotation of the electric motor was correct. But what about the rotation of the new pump? Bit hard to tell when it's submerged in the tank.

After speaking with the technician on my cell, I was reasonably confident the new pump's rotation was correct. But just to be sure, I decided to try reversing the rotation of the electric motor. No change.

Now what? I don't have a flow-tester with me and it's a major job to lift the tank lid. It appears that new pump is either faulty or not priming. Unlike a vane pump which needs a head of oil on its outlet for the vanes to 'throw' and start pumping, a gear pump is normally considered self-priming - especially when its submerged in hydraulic oil.

To give the new pump the best possible chance of priming, I topped off the oil level at maximum. Still no charge pressure after running for a minute. In the absence of a flow-meter, I decided to lift the electric motor off its bell housing, disconnect the pipes from the pump's outlet penetrations in the top of the tank and turn the pump by hand.

This was revealing. The front section was pumping, but the rear section wasn't. Joy. The rear section was faulty. I continued turning the pump by hand, while I wondered what the chances were of this happening, and contemplated the work involved in lifting the tank lid.

Just as I was about to give up and call for reinforcements, I noticed oil was being displaced from the rear pump's outlet penetration in the top of the tank. It WAS pumping. I reconnected the plumbing, dropped the electric motor back into position and bingo. We had accumulator charge.

Had I been told this story about a gear pump that wouldn't prime itself - I would have struggled to believe it. Yes it IS strange but true.

"This book has the potential to save many organizations lots of m0ney. It should be on the bookshelf of every engineer, supervisor, planner and technician that deals with hydraulic equipment... it's worth its weight in gold." Find out more

Alexander (Sandy) Dunn
Plant Maintenance Resource Center

3.   How to synchronize hydraulic cylinders

The problem of synchronizing multiple hydraulic cylinders arises in many applications. This Instant Knowledge report introduces and explains eight different solutions to this problem. To assist you in selecting the most suitable solution for your application, each method is considered according to its level of accuracy, cost and complexity. The methods discussed are applicable to any number and any type of hydraulic actuator. Find out more

4. Content for your web site or e-zine

Need some fresh content for your web site or e-zine? You now have permission to reprint these 'Inside Hydraulics' articles on your web site or in your e-zine, provided:

1. Each article is printed in its full form with no changes.

2. You send an e-mail to to advise us where you'll be publishing them.

3. You include the following acknowledgement at the end of each article:
About the Author: Brendan Casey has more than 17 years experience in the maintenance, repair and overhaul of mobile and industrial hydraulic equipment. For more information on reducing the operating cost and increasing the uptime of your hydraulic equipment, visit his web site:

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6. Tell us what you think

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