Hamworthy Svanehøj has launched the first of what will become an entirely new range of combined sea water lift and fire pumps that meet the requirements of the offshore market.
The new deepwell seawater lifting pumps and fire pumps ’DWS’ will be available ranging in capacity from 700 m3/hr to 1700 m3/hr and with a differential pressure up to 180 mlc. The pumps are driven by a dry mounted electric motor in explosion-proof execution, through a pipe stack with transmission shaft and cargo lubricated bearings. These pumps are in addition to in-line Hamworthy pumps already available for seawater lift and firewater applications.
“With our strong focus on the offshore industry, it has been our overall objective to develop a series of sea water lift and fire pumps that fulfill the requirements of API610 and NFPA-20, secure long Mean Time Between Repair (MTBR), and reliable and efficient operation ,” said Lars Fischer, Offshore Sales Director of Hamworthy Svanehøj.
He said that, the pump head is designed for optimum efficiency using the company´s design experience, computational fluid dynamics and full scale tests. Impellers have been trimmed to provide 15% higher head per flow unit, while the semi-radial design provide a more stable performance curve at higher capacities.
After finite element analysis, moulded intermediate chambers had been selected to maximise stiffness, with the result that weight across the new range had been reduced by 30% compared to similarly constructed units featuring welded chambers.
Considerable attention has also been given to bearing performance. The use of conical thrust bearings in the upper drive shaft arrangement minimises vibrations. Furthermore the thrust bearing arrangement has been designed with oil circulation for American Petroleum Institute (API) compliance and increased lifespan. The distance between the transmission shaft bearings is in accordance to API610 in order to assure stable operation under all service conditions.
The pump can be delivered either with a labyrinth seal or mechanical seal. The mechanical seal is of the cartridge type and as an option it can be delivered in compliance with API682.
For sea water lift pumps and fire pumps installed in caissons, Hamworthy Svanehøj can supply its patented inflatable intermediate support system. The support system is developed in order to secure proper installation and support of the pump in the caisson.
Mr Fischer said that the new DWS pumps will be available in a wide range of materials, such as AISI 316L, Duplex and Super Duplex. Optionally the pumps can be delivered with strainer, galvanic protection and anti fouling system.
He also said that, initially, the new range of pumps was being aimed at seawater lifting and firefighting, but finds the new pumps can also naturally be used in modified executions for applications involving chemicals, condensate and liquefied natural gas and liquefied petroleum gas. Other possible applications include CO2 pumping, onshore as well as offshore and onshore oil storage.