Submersible pump (submerged cargo pump) is manufactured by Frank Mohn AS, that’s why it is a.k.a (FRAMO Pump)
It is a vertical single stage centrifugal pump powered by a hydraulic motor for safe and efficient operation.
Pump elements, casing and pipework are of stainless steel, smooth and easy to clean surfaces with a limited number of flanges.
It has built in hydraulic motor connected to impeller by short independent shaft.
Motor, shaft and bearings are lubricated and cooled by hydraulic driving oil
Whole assembly is submerged in fluid to be pumped, that’s why it is called submersible pump
Centrifugal pump has centrifugal force action caused by the high speed (rotational) of impeller, loss of kinetic energy in diffuser where a conversion of kinetic energy to pressure energy takes place. When the fluid enter the pump, it is lifted by pump.
Working pressure of hydraulic unit is as much as 170 bar and return pressure is about 3-4 bar.
Pump suction is positioned close to the bottom of the tank suction well for good tank drainage.
A stripping pump connection is provided to discharge the remaining cargo, It is a reciprocating pump.
When pumping is completed, purging connection fitted to clear the discharge pipe. (purging should be carried out at regular intervals)
Cargo pump cofferdam is essential for segregation of the pump hydraulic section from cargo and for seal monitoring.
- Segregation of cargoes for vessel’s safety and environmental safety.
- Maximum transport volume.
- Efficient stripping and tank cleaning.
- Hydraulic system without any electrical power equipment in cargo area.
- Automatic regulation of power needed and impossible to overload.
- Do not use higher hydraulic pressure on the system than necessary.
- Mixing of different hydraulic oils should be avoided.
- Avoid air in the hydraulic system.
- Keep the hydraulic system clean.
(+) points :
- Unlike other pumps, they do not need to be primed before operating. This not only saves time, but also reduces risks of over exertion.
(-) points :
- Hard to identify and repair damages (i.e rupture).