installed four limit switches in their lifts currently in operation on the Atwood Osprey, an ultra-deepwater moored semi-submersible with a drill depth of 32,000 ft. The Atwood Osprey is currently drilling in the Indian Ocean off Australia’s western coast.
Four Alimak SE700 lifts installed in 2010 on the Atwood Osprey function as the primary means of access to the rig’s four levels. The SE700s are located in each of the rig’s four columns, providing transport for operators and equipment between the base pump room and the top ‘dance-floor’.
Alimak Hek recently acquired a contract to engineer and install four limit switches to be fitted into each of the rig’s lift columns as an additional safety feature. Located on the emergency hatch above each lift, the limit switches would prevent the SE lifts from operating when the emergency hatch is open, ensuring a high level of safety for operators.
Alimak Hek worked with Atwood Oceanics and ABS to implement the safety improvement on the Atwood Osprey.
A key reset switch is located on the base electrical panel of each lift, requiring operators to reset the system once the limit switch is engaged. In this situation a signal alerts the control room that the switch has been triggered and power to the lift has been cut as a result. Both limit switches and key reset systems are manufactured from 316 stainless steel to ensure corrosion resistance in the marine environment.