March 14, 2006 

'Inside Hydraulics' Newsletter

1. Water in oil monitoring made easy
2. Addressing fluid power leaks - both types
3. Advanced hydraulics troubleshooting
4. Content for your web site or e-zine
5. Help us spread the word
6. Tell us what you think


Water in oil monitoring made easy

Need to know if your lubrication, heavy oil, diesel fuel or hydraulic system is being contaminated with parts per million or percent amounts of water? Millions of dollars are lost every year through untimely machine failures or reduced equipment life attributable to inadequate warning of water contamination.

EESIFLO has for some time been working on the development of stable and accurate water in oil measurement down to 35 ppm. The end result has been the production of the EASZ-1 loop powered, temperature compensated water in oil sensor that continually samples the oil in a closed system. The principal of measurement is old but trusted science - using the dielectric properties of the mixture to obtain contamination values - but without any drift in the electronics and therefore no requirement for factory recalibration. The EASZ-1 accurately measures water content in all types of oils whatever their density. Features include:

  • one second response time
  • site re-calibrateable
  • no need for continual sensor replacement
  • user selectable ranges
  • lightweight rugged construction
  • resolution 30 ppm

EESIFLO's EASZ-1 water in oil analyzer

The EASZ-1 Water in oil monitor.

Installation is simple and the EASZ-1 incorporates rugged sensor elements that stand the test of time. Accurate water in oil measurement has never been easier. For more information, or to locate your nearest EESIFLO representative, go to

Get a lifetime of hydraulics knowledge...

Get 'Industrial Hydraulic Control'
. Find out more

2.   Addressing fluid power leaks - both types

In a previous 'Inside Hydraulics' article I discussed the true cost of hydraulic oil leaks. In the case of oil leaks, the cost areas that need to be considered include:

  • Make-up fluid;
  • Clean-up;
  • Disposal;
  • Contaminant ingress; and
  • Safety.

But what about hydraulics' fluid power cousin - pneumatics? One of the advantages that pneumatics has over hydraulics is its cleanness. Air leaks are much easier to ignore than oil leaks because they don't draw attention to themselves in the same way. You don't need to worry yourself with clean-up and disposal costs. Contaminant ingression is possible, but is generally not a major concern. And unless the leak is significant, safety is not usually a big issue either. So that leaves make-up fluid (air).

Make-up air

While air is free - clean, dry compressed air is not. In considering the cost of make-up air for a pneumatics system the following need to be considered:

  • Depreciation (wear and tear) of the compressor;
  • Conditioning costs - filtration, drying and lubrication; and
  • Energy cost of compression.

The ideal leakage rate is of course zero, but when calculating the free air delivery (FAD) required by a pneumatic system a rule of thumb is to allow for leakage of 10% of total flow rate. Consider a 10 cubic meter/minute system leaking one cubic meter/minute. The power required to compress one cubic meter (35.3 cubic feet) of air per minute to a pressure of 6 bar (90 PSI) is approximately 5.2 kW. At an electricity cost of $0.10/kWh this leakage is costing over 50 cents per hour in electricity consumption alone. In a 24/7/365 operation that amounts to $4500 per year!

Quantifying losses

While a leakage rate of 10% of flow rate may sound high and would be unsustainable in a hydraulic system, air leakage rates as high as 25% are not unheard of - even in apparently well maintained pneumatic systems. The actual leakage rate of a system can be calculated using the following formula:

QL = QC* t / (T+t)

QL = System leakage rate (cubic meters/minute)
QC = Compressor FAD (cubic meters/minute)
T = Leakage time - time between compressor cut-out and cut-in (minutes)
t = Charging time - time between compressor cut-in and cut-out (minutes)


As demonstrated by the above example, the annual cost of air leaks in pneumatic systems can be significant - in power consumption alone. Conduct regular leakage tests on your pneumatic systems and take necessary action to locate and rectify leaks as required. For more on the operation and maintenance of compressed air systems and pneumatic equipment visit:

"Thanks for the great work on the two publications, Insider Secrets to Hydraulics and Preventing Hydraulic Failures. I have been in the hydraulics business for the past 20 years and it is very difficult to find any decent material on hydraulic maintenance, troubleshooting and failure analysis. These two books cover it all in easy to understand language... I conduct hydraulic training courses and plan to purchase copies to distribute to my students to share your practical approach to understanding a not so understandable subject."

Paul W. Craven, Certified Fluid Power Specialist
Motion Industries, Inc.

3.   Advanced hydraulics troubleshooting

'Advanced Hydraulics Troubleshooting' covers four case studies representing the most common types of hydraulic service calls technicians encounter on hydraulically powered equipment. The viewer is challenged to develop their own diagnosis before the cause of each problem is explained. Common mistakes technicians make when diagnosing hydraulic problems are illustrated along with procedures for avoiding these costly errors. 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 16 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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