It can be difficult to identify the cause of a hydraulic system failure. Although a sump, motor, pump, valves, actuators, and hydraulic fluid make up most of a hydraulic system, these components could fail. Not to mention the additional risk of failure brought on by mistakes made by people and poor maintenance procedures.
If your system malfunctions, you need to understand why, how to identify the issue, and how to keep it functioning properly moving forward while maintaining worker safety.
Typical Reasons for Hydraulic Failure
When a hydraulic system malfunctions, it is frequently simple to identify the symptoms, including high temperatures, low-pressure measurements, and sluggish or unpredictable functioning. What are the most frequent reasons for hydraulic system failures, though? Most hydraulic problems have one of the following common causes, which we can identify.
Issues with Temperature
Too-hot or too-cold hydraulic systems might develop serious issues over time. Some of these difficulties include the symptom list below.
Hydraulic fluid thinning due to heat can prevent lubrication and increase the likelihood of leakage.
Oxidation of the fluid: Hydraulic fluid can thicken and oxidize under extremely hot temperatures. In addition to reducing the system’s capacity to disperse heat, this fluid thickening can lead to accumulations in the system that limit flow.
Fluid thickening: Hydraulic oil becomes more viscous at low temperatures, making it more difficult for the oil to reach the pump. When loads are applied before the oil reaches 70 degrees or above, cavitation damage can occur in systems.
Hydraulic Pressures Are Not Adjusted Correctly
Several changes may be made to every hydraulic system. When a machine malfunctions, the hydraulic pumps, and valves’ knobs are turned to “see” if the issue is resolved. Sadly, the individual adjusting frequently has no idea how it will affect the equipment. In a hydraulic system, pressures are frequently set too high. The assumption is that a machine will operate more quickly at higher pressures.
Absence of Hydraulic and Accumulator Safety Protocols
The pump’s electric drive motor is shut off, and lockout procedures are carried out when a machine has to be repaired. Seldom is the pressure gauge checked before work on or around the machine begins. Hydraulic energy is stored as pressured fluid in accumulators. The high-pressure fluid in the accumulator can drain to the tank via an automatic or manual dump valve in most systems, allowing the pressure to drop to zero. The pressure oil in the accumulator will be maintained if the automated dump valves fail to stay closed.
One can be injected with high-pressure fluid if a line is severed or a part is removed. The human element comes into play when a manual dump valve is employed. At one factory, a young millwright was gravely hurt when he was sprayed with high-pressure oil after failing to open the hand valve. Before working on the system, there was no procedure for opening the valve.
The gauge is frequently found on the check valve’s pump side rather than the accumulator side. As the oil leaks into the tank through the internal tolerances of the hydraulic pump, the gauge will decrease to zero when the pump is switched off. The operator or maintenance worker believes there is no pressure and cannot determine whether the pressure fluid in the accumulator has been released. A gauge should be put at or close to the accumulator on systems of this design.
Quality and Levels of Fluid
The performance of hydraulic systems can be impacted by fluid quality and quantity. Inadequate filtration and low fluid levels can lead to air pollution, whereas fluid contamination can result in temperature issues. Leaks can make both problems worse.
It’s also crucial to use the right fluid because different hydraulic oils are suitable for different uses. Even oil choices are available that provide greater resistance to issues caused by temperature. Even some lubricants come with anti-wear and anti-foam compounds to assist guard against wear and, correspondingly, air contamination.
Ineffective Troubleshooting Methods
When a hydraulic issue arises, information must be obtained to identify the problematic component. Examples include examining the pump case drain flow or the system’s heat level. The manager will frequently step in and order the replacement of the pump, cylinder, or other part. At one factory, a manager told a millwright to manually open a directional valve rather than troubleshoot. As a result, an accumulator discharged into a 5,000-gallon reservoir that was only partially full. The mill was shut down for seven days as a result of the reservoir’s top blowing off.
The product’s manual for the machine, which is frequently housed in a maintenance office or storage, will typically contain hydraulic diagrams. The last thing a maintenance worker wants to do when a hydraulic issue arises is search for the manual for 15 or 20 minutes. After all, lost time means lost money when a machine is down. A Plexiglas cover mounted over larger schematics by the system is a preferable alternative. It is possible to laminate and position smaller prints identically. The schematic will be used if it is easily accessible.
Have you ever been requested to investigate a hydraulic problem? When diagnosing and resolving the issue, everyone—whether a maintenance worker, salesperson, service provider, or consultant—should adhere to the same rules.
In many factories, troubleshooting is accomplished by a parts-changing procedure, which can be costly in terms of delay and part costs. Also, because so many random things were done, no one has learned anything when the system eventually starts up.
Determine the issue
Most hydraulic problems fall into one of two categories: pressure-related or volume-related. When the pressure doesn’t develop to a level that the machine can withstand, there is a pressure problem.
For instance, a press might need 3,000 pounds per square inch (psi) of pressure to compress or process a board, but it only builds to 2,000 psi. A volume issue is almost certainly present if the problem is speed-related. This indicates that either the pump is not supplying the requisite volume of oil or that there is system-wide bypassing.
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