Hydraulic hose that tells you when it is about to fail is not science fiction anymore.
Eaton and Purdue have developed and patented a new hydraulic hose technology, Eaton LifeSense. This monitors the health of hydraulic hose assemblies, detects events that have been shown to be symptomatic of the hose beginning to fail and notifies the user prior to failure, with enough time to replace the hose before it fails.
Finding a better way
Hydraulic hose has a finite life that ultimately ends in failure. Since the cost of failure in terms of unscheduled equipment downtime, environmental spills, equipment damage and safety can be very high, it is common practice to replace hoses on a regular schedule before they reach the end of their useful life.
Hose manufacturers have supported this approach with various predictive formulae that consider time, pressure, temperature, the number of flex cycles and other factors, to produce an approximation of expected hose life. This approach causes millions of metres of good hose to be discarded every year, often long before the end of the service life.
True condition monitoring
The LifeSense system includes a new hose incorporating at least one conductor in its construction, a special end fitting that serves as both a hydraulic and an electrical connector and a diagnostic unit containing the monitoring electronics and operator notification interface. Eaton LifeSense hose is offered initially in factory assemblies with straight JIC swivel fittings in the widely used -8, -12 and -16 sizes.
It offers performance equal to industry standard EN856 2SN rated hose and, while a unique construction, is certified to the same industry specifications as conventional hydraulic hose products qualified to the 2SN specification. Additional sizes and fitting configurations are planned for future product line expansions.
Although the specifics of construction and monitoring technology are proprietary, the LifeSense system is based on the fact that certain electrical properties of the hose change as the hose approaches failure. Comparing periodic samples of these properties to a baseline value gives a highly reliable indicator of imminent hose failure, with sufficient warning time for an operator to complete an operation, or in most cases a shift, before the equipment needs to be shut down for hose replacement.
The LifeSense diagnostic unit contains the electronics necessary to implement the sampling schedule and store enough data to support the necessary comparisons, a proprietary algorithm to detect the relevant changes, and a simple LED output to notify the operator of hose condition. In the initial product offering the diagnostic unit is hardwired to the fittings on the LifeSense hose assembly. One diagnostic unit can monitor inputs from up to 11 hose assemblies.
Bottom line benefits
During the laboratory testing phase, it was discovered that most of the hoses replaced on a time based schedule of estimated useful life had actually reached only slightly more than half of their safe useful life in the test protocol. In other words, the ability to detect imminent failure accurately can extend the useful service life of these hoses by over 50%. Extrapolating that number to the millions of metres of hose being replaced on schedule indicates a significant saving for end users of all kinds of hydraulic systems.
The amount of downtime required for hose replacement is also an important factor in operating cost. LifeSense technology can significantly reduce unscheduled downtime related to hose failure. Another major financial impact of LifeSense technology will be a significant reduction in the number of hydraulic fluid spills caused by hose failure.
Eaton LifeSense hose is the first fluid conveyance product ever offered with the ability to monitor itself, detect unhealthy symptoms and warn the user of imminent failure. As the technology behind it expands and matures it is possible to envision a time when hydraulic hose failures will no longer be a major concern for equipment operators.
For more information contact Emil Berning, Eaton Hydraulics, +27 (0)11 961 2400, infoza@eaton.com, www.eaton.com
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