Pressure Tests for ANFOG Gliders
"How many leaks have your gliders had?", is a question that never fails to come up whenever ocean glider personnel meet at international functions.
Due to the high water pressures that ocean gliders have to withstand while repeatedly probing deep into the oceans, it is of no surprise that water leakage has been an all too common problem encountered by gliders everywhere. A water leak midway through a glider mission usually spells the end of the mission and requires emergency retrieval of the glider. However, at the Australia Facility for Ocean Gliders (ANFOG), this is no longer the case.
It is part of ANFOG operations protocol to pressure test ocean gliders prior to every mission to ensure that leakages will not pose any problems. To do this, technology developed for the oil and gas industry is used. The glider is submerged in water in a test tank, which is then pressurised to 290 pounds per square inch. The pressure valve is shut off, and the pressure in the test chamber monitored very closely using very high sensitivity sensors. Any minute water leakage in the glider is detected as a drop in tank pressure. The test is designed to simulate the ocean glider being at a depth of 200 metres for 1 hour.
ANFOG pressure testing commenced in March this year. All gliders which have been pressure tested prior to deployment have not leaked when put into operation.