Q & A

"How do I know if I have water in my hydraulic oil?"

Water in oil can be either dissolved, emulsified or free. Dissolved water must be discovered through the use of oil analysis or capacitance-type dew point meters (available online or portable). Dissolved water cannot be visually observed. Emulsified water will show up in the form of a cloud or slight haze in the oil. Free water can be seen at the bottom of the reservoir or in a BS&W bowl (Bottom Sediment and Water Bowl) installed at a convenient low point in the reservoir.

While most would like to maintain completely water-free sumps, it is likely that most hydraulic reservoirs will have some amount of dissolved water. Take action if the oil becomes cloudy or if the PPM level rises above roughly 350 PPM (0.035%) for most industrial applications. On-site or in the field, free and emulsified water can be detected using the crackle test (hot plate or soldering iron) or by the calcium hydride method.

Today's Tip

• When replacing a conventional bearing with a sealed bearing, be sure to remove and plug the zirk fittings and consider using industrial data markers to indicate that sealed bearings are being used. An industrial data marker is a soft aluminum tag that can be permanently marked and attached. (Tip submitted by Randy Norton, Plant Maintenance Optimization Coordinator, Tuscon Electric Power Co.)

Each tip published will earn the sender $10. Send your tips to webmaster@noria.com or fax to 918-746-0925.

Book Bits

From the book "Lubrication for Industry":

"In order to move grease to the application point, it needs to be pumped. Most delivery systems for oil utilize pumps that work in the 50 psi (2.3 bar) - 250 psi (17.2 bar) range. Grease, on the other hand, requires a pump that will deliver pressure above 1500 psi (103 bar).

In the hands of an untrained operator, an ordinary grease gun can deliver a pressure of up to 15,000 psi (1030 bar)! A bearing seal, on the other hand, will rarely rate higher than 500 psi (35 bar). Once the seal on the bearing is compromised, the bearing is well on its way to early failure. A compromised bearing seal encourages dirt ingestion and overlubrication due to its lack of "back pressure" (this is especially true when greasing a bearing "blind" from a remote zirk fitting). The secondary negative effects produced are extra consumption of grease, and extra time required for cleanups of equipment with the overflowed grease, inviting dirt and contaminants to stick to it. Respect the power of a lowly manual grease gun.

Maintenance Tip: Always ensure that the dispensing nozzle of the grease or oil gun is cleaned before use, and that the fitting it is being attached to is also clean. This will safeguard against unnecessary introduction of dirt into the bearing.

For more information about the book "Lubrication for Industry" go to:

http://www.noria.com/secure/product_detail.asp?catalogid=9

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Lube-Tips is published by Noria Corporation. Oil Analysis and Lubrication Experts