What is ballast pump

Centrifugal pump dictionary

The term "ship pump" is the collective term for all pumps that comply with the relevant regulations of the classification societies for shipbuilding.

The ship's pump as a centrifugal pump has extremely versatile uses on board (see pump application area). So it comes in the engine room as a boiler feed, condensate and centrifugal pump for sea and fresh cooling water, in the bow as a transverse jet, in special pump rooms as a loading oil, Butterworth and ballast pump, in special functions as a roll, heel, trim, bilge pump. , Bilge, fire-fighting and various service pumps. The dock pump is also one of the ship pumps. Pumps for seawater and fresh cooling water (e.g. the seawater pump) as well as for fire extinguishing draw their liquid from the sea chests via suction lines. These are on the inside of the ship's side below the waterline arranged containers with seaward facing openings that are covered by inlet rakes. The seawater as the pumping medium requires the appropriate materials for the pump: gunmetal or bronze (e.g. as multi-component aluminum bronze) for the pump housing and the impeller and chrome-nickel steel for the pump shaft.

Since larger amounts of air often have to be removed from bilge and ballast water pipes, there are often self-priming pumps on board. These are continuously rotating water ring pumps. Separate ventilation devices (see ventilation) such as ejectors or central vacuum systems are also becoming increasingly popular.

Due to the limited space on board, the transversely divided (see transverse division) vertical pump with a directly attached motor has emerged as the most suitable design for most ship pumps. see Fig. 1 ship pump

Fig. 1 Ship pump: Transversely divided, vertical ship pump, "Inline" design

The longitudinal division also occurs occasionally. see Fig. 2 ship pump

Fig. 2 Ship pump: Longitudinally split, vertical ship pump

The delivery flow range of a vertical, transversely divided ship pump ranges from 30 to 1200 m3/ h at delivery heights of 15 to 125 m. The impeller is single-flow for small flows and double-flow for larger flows (see multi-flow pump). The pump shaft is guided in grease-lubricated roller bearings outside the pump housing. After removing the coupling spacer sleeve (see shaft coupling), the running gear can easily be lifted upwards for inspection or repair. The motor does not have to be dismantled and the pump housing can also remain on its pump foundation.

A longitudinally split, vertical ship pump is used for flow rates from 1,000 to 5,000 m3/ h at 15 to 85 m delivery head.

The pump shaft is guided below the shaft coupling in a grease-lubricated roller bearing and below the impeller in a slide bearing lubricated by the pumped medium. To dismantle the pump rotor, the front part of the housing must first be removed to the side. see Fig. 1 ship pump

On turbine ships with large boiler systems and corresponding condensers, twin-flow centrifugal pumps are used for the cooling water supply. Due to the small delivery heights, propeller pumps in a longitudinally split design are also common.

Ship condensate pumps have to work at the lowest inlet heights. The impeller of the first stage (suction impeller) is arranged at the bottom as a specially designed impeller and is also flown against from below. Additional rotors can be provided to improve the NPSHR value. The storage is outside of the pumped medium.

The flow rates range from 5 to 250 m3/ h and delivery heights from 30 to 140 m are possible.