British company Midland Preventative Maintenance has developed a software-based non-invasive test for hydraulically powered roof supports used in longwall mining.
The software package is used in conjunction with portable monitoring equipment to check relief valves, valve block modules and internal seals on cylinders and legs. The company said because tests are non-invasive the possibility of hydraulic fluid contamination is obviated.
Testing is carried out by assessing ultrasonic noise generated when a fluid flows through an orifice. Factors which affect this noise include operational pressure and temperature, orifice shape and design, and piston diameter. The hand-held portable test systems detect noise as low as 50ml/min and measures it in decibels. The software then calculates bypass flows and generates an exception report which advises desirable remedial action.
The company said hydraulic component integrity testing is invaluable at all stages of powered roof support.
"At commissioning it indicates any early defects while supports are covered by warranty and during the supports' operational life it warns of developing defects and the need for maintenance, thus ensuring continuous efficiency," MPM said. "Finally it can check a system being transferred to a new environment and by assessing spares requirements, reduces future overhaul costs."