Intrinsic Hydraulic Hose Condition Monitoring for Prevention of Catastrophic Failure

Abstract

High-pressure hydraulic hoses are used throughout industry to transmit fluid power. The current state of the art in hose replacement consists of two strategies; these are (1) replacement upon failure and (2) time-based replacement. For the replacement upon failure method, end users inspect hoses and either replace when there is obvious physical damage or the hose has burst and allowed the release of fluid under high pressure. Hose users that employ time-based replacement cycles often collect data and either subjectively or statistically choose a replacement frequency intended to prevent unexpected failures. Engineers at Eaton Corporation worked with Purdue University to develop an alternative. A novel hose construction using two conductors with an isolating layer provides a component in an electrical circuit which can be monitored to determine the status, or health, of a hose in operation. The first step in this development was the realization that hose failure is a process and not an event. By tracking a hose’s electrical signature and characterizing the change that occurs when the internal structure begins to break down, a user is alerted prior to a catastrophic hose failure. Eaton is developing notification systems capable of both monitoring the hose’s electrical signature and alerting an equipment user prior to unexpected failure. The system requires direct electrical connection to the hose fitting for monitoring. There are currently two strategies in development, a wired system and a wireless system. The wired system uses a remote diagnostic unit with cables running to each hose assembly to query the hose and alert an equipment user directly. The wireless system employs battery-powered sensors installed on a hose assembly which communicate with a gateway located nearby. When a hose approaches its end of life a warning is issued by illuminating a warning light or issuing a remote warning through a cellular or wireless network. There are significant gains in the ability to prevent hydraulic hose failures. These unexpected incidents lead to downtime, damage to equipment, environmental damage, and serious personal injury. Additionally, using this advanced warning system allows users to use nearly a hose’s entire life. This improves asset utilization considerable when compared to the useful life sacrificed by using time-based replacement schedules. This technology will reduce operating costs and prevent downtime, environmental incidents, and the threat of personal injury present when hydraulic hose fails.