First established in 1136, Aberdeen Harbour is claimed to be the oldest existing business in the UK, with a history that has spanned almost 900 years. Today, it is acts as a marine support centre for the oil and gas industry, with the main commercial port serving North East Scotland.
P&M Pumps, in conjunction with Ritchie Mackenzie, who specialises in pumping and control engineering, has recently provided help in solving pumping problems occurring in the dry dock at the harbour.
The existing scavenge pumps, originally installed to provide a duty of 600gpm at 35ft head, including a 7” suction lift, were failing due to problems of blockages. This was due to the variety of debris entering the sump and, even when running successfully, they were struggling to keep up with constant inflow of sea water flowing into the dry dock via the sea gates.
The solution was to replace the existing dual macerator and sump scavenge pumps with progressing cavity pumps, specifically Vaughan Chopper Pumps with motors rated at 18.5kW at 1470 rpm, 415V/3ph/50Hz. The new pumps would be self-priming and mounted complete with the motors, including variable speed drive and capable of exceeding the original duty conditions.
Ritchie Mackenzie was responsible for all the modifications required to fit the new pumps, including a new control panel enabling control of the variable speed drive. This would include the ability to alter the frequency of the pump motor, which would help to optimise efficiency in meeting the duty point and subsequently reduce running costs.
The control panel also includes an ultrasonic level controller that monitors the level of water in the dry dock sump. The controller indicates the liquid level on an LCD screen on the panel facia after receiving a level signal from the ultrasonic head positioned in the dry dock and which is set to cut the pump off at low level to prevent dry-running.
In addition, the pump motors have heaters installed to protect the electrical windings against moisture ingress along with a temperature sensor/fault indicator, which will trigger a warning in the event of over-heating.