Hydraulic fluid acts as the lubricant between moving parts and often provides the necessary resistance in components. Heavy equipment that is exposed to harsh and temperature fluctuating environments such as off-road earth moving equipment and farming equipment require regular monitoring of fluid contamination. In an industrial plant, the machinery that encounters regular actuation or travel may also be subject to contaminates.
Hydraulic fluids are formulated with additives developed for the specific application. These additives are typically made by companies who specialize in petroleum based materials. Additive manufactures develop specialized additives made specifically for hydraulic oil for construction equipment. The additives consist of chemical compounds that protect the base stock of natural mineral oil-based fluids.
For certain equipment that is more sensitive or regularly exposed to dirty environments such as construction machinery, it is vital to have well organized contamination control procedures. This includes periodic testing of the cleanliness of the hydraulic fluid by following the OEM’s recommendations. There should also be filters placed at regular intervals in the system to block contaminant that can work their way into the line.Testing the fluid is performed in-line with test point fittings placed at regular intervals throughout the system. Well designed test point connections are leak-proof before the ball check is open; this along with the self-locking metal cap minimizes the risk of back flow contamination into the system. Testing fluids in-line permits sampling at working pressure without disrupting the system’s operation. Otherwise the equipment must be shut down for extra maintenance outside of the normal planned maintenance schedule. Most maintenance professionals maintain a full line of test point components, or a variety of test point kits. The kits include all styles of connections, test hoses, couplings, pressure gages, gage adapters, plugs and probes. Having multiple styles of test points available makes it easy for periodic testing of a wide variety of OEM equipment.Hydraulic fluid testing should be performed after new fluid is added, new components or hoses are placed in line or any other situation that may expose the fluid to the environment. It is often overlooked that new fluid straight from the supplier can be contaminated.