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Pumps

Pump

A ship's pump is any machine that moves seawater, fuel, lubricating oil or ballast through the hull, built around one of two working principles: centrifugal, relying on continuous flow and impeller speed, or positive displacement, moving a fixed volume per revolution regardless of downstream pressure.

523models
DESMI
Knowledge

What to check on a Pump.

523 models from DESMI in Pump. Below: the full model list.

What this type covers

Pump on an engine room equipment list covers a wide family of machines that share a job, moving liquid, but not a single design. Centrifugal pumps dominate high-flow, moderate-pressure duties such as seawater cooling, ballast and general service, converting impeller speed into flow and only building pressure as a consequence of downstream resistance. Positive-displacement pumps, including gear, screw, reciprocating and vane types, move a fixed volume each revolution or stroke almost regardless of downstream pressure, which makes them the choice for viscous liquids such as heavy fuel oil and lubricating oil, and for duties needing steady metered flow such as fuel injection.

Centrifugal pump, end-suction section
Section through an end-suction centrifugal pump along the shaft axis: liquid enters axially through the suction branch into the impeller eye, the rotating impeller throws it outward into the volute casing and up through the discharge branch, while the shaft passes through the mechanical seal into the bearing housing and the coupling to the driver.

Legend

  1. Discharge outlet
  2. Suction inlet (axial, into the eye)
  3. Mechanical seal
  4. Bearing housing
  5. Pump shaft
  6. Coupling to the driver
  7. Impeller (rotating vanes)
  8. Volute casing

Main components

Casing and impeller or rotor set

A centrifugal pump's volute casing and impeller convert rotational energy into flow and head; a positive-displacement pump's meshing gears, screws or vanes trap and carry liquid through the casing in discrete pockets, which is why it cannot be run against a fully closed valve without a relief valve fitted, unlike a centrifugal pump that simply deadheads at zero flow.

Shaft seal

A mechanical seal, or on older or simpler pumps a gland packing, keeps the pumped liquid from leaking out along the shaft. Mechanical seals need a clean, correctly aligned seal face and adequate flushing or cooling; packing needs periodic adjustment and accepts a small controlled drip as normal, a distinction that matters when a crew trained on one seal type is sent to check the other.

Read the full guide

Bearings and coupling

Rolling-element bearings support the shaft and are lubricated by grease or, on larger pumps, a shared oil system; a flexible coupling connects the pump to its prime mover and tolerates the small residual misalignment that even a carefully aligned installation retains.

Prime mover

Most ship's pumps are electric-motor driven; some essential pumps such as emergency bilge or fire pumps have a diesel-driven or otherwise independent prime mover specifically so they remain available after a loss of the main electrical supply.

Selection and sizing

FactorWhy it matters
Flow rate and headsets pump type and size against the system curve of the piping it serves
NPSH available versus requiredinsufficient margin causes cavitation regardless of how well the pump otherwise matches the duty
Liquid viscosityhigh-viscosity liquids favour positive-displacement types; centrifugal pumps lose efficiency sharply as viscosity rises
Materialsbronze, duplex or coated wetted parts for seawater service versus carbon steel for fuel and lube oil

Regulations and class

SOLAS and class rules require duplication or independent backup for essential pumping services, including bilge, fire, cooling water and fuel transfer, so that a single pump failure does not remove the function entirely. The emergency bilge pump and fire pump requirements under SOLAS Chapter II-1 and II-2 call for a source of power independent of the main engine room in many ship types, which is why these particular pumps are diesel-driven or supplied from the emergency switchboard rather than sharing the main pump room's electrical feed.

Typical faults

  • Cavitation from insufficient NPSH - pitted impeller vanes, noise, falling flow, often from a partially blocked suction strainer or a suction lift that has grown since commissioning.
  • Mechanical seal failure - leakage at the shaft, usually from dry running, misalignment, or a flushing line blocked or shut for other work and not reopened.
  • Bearing failure from misalignment - heat and vibration at the bearing housing, traceable to coupling wear or a foundation that has settled.
  • Air lock in a centrifugal pump - loss of prime and no flow despite the pump running, common after maintenance that opened the suction line.
  • Excessive internal clearance wear on positive-displacement types - falling delivered flow at the same speed, reducing fuel injection consistency or transfer rate without an obvious external symptom.

What to look for in a supplier

  • Wear parts and mechanical seal kits specific to the pump model, since seal faces and elastomer compatibility vary by liquid service.
  • Documented performance curves so a replacement or repaired pump can be checked against its original duty point, not just against similar ratings.
  • Materials matched to the actual liquid handled, particularly for seawater service where the wrong alloy shortens service life significantly.

When a centrifugal pump loses flow, check for an air lock or blocked strainer before assuming impeller wear - most sudden flow loss on these pumps is a priming or suction problem, not a worn part.

Models

Models in this type.

The best-documented model of each manufacturer first, then the next — 100 of 523 models in Pump. Every row links to full specifications, documents and service notes.

Showing only DESMI. Show all manufacturers
All manufacturersGrundfos 706DESMI 667INOXPA 205Sea Recovery 106Viking Pump 98IMO/Colfax 93Alfa Laval 79SHURflo 74Johnson Pump 67Hanla IMS 63RKI Instruments 56Twin Disc 52Kawasaki 41Sulzer 36NAFFCO 35SVANEHØJ 35TAIKO 35Emerson 30Framo 29Shinko 29
Sort by:Best documentedNamePower (kW)
DESMINSL125-330 162 m3/h DESMI-12 -KOMB. DESMI-12-COMB DESMI-12-KOMB DESMI100-265/-02 WITH INDUCER DESMI100-330/-02С ИНДУКТОР DESMI125-330/-02 WITH INDUCER DESMI14) HATZ 1B20 DESMI150-265/-G DESMI2(C)D DESMI2(C)D-Ex DESMI265 in 02-Ausführung DESMI265 in 12-Ausführung DESMI300-418 02-COMB DESMI300-418 AND 350-525 12-COMB. DESMI300-418 И 350-525 12-КОМБ DESMI320D DESMI320W DESMI325D DESMI330D DESMI350-525 02-COMB. DESMI4(C)D DESMI4(C)D-Ex DESMI4(C)W(D) DESMI4(C)W(D)-Ex DESMI40/10-2 B DESMI525 -12 UDF DESMI525 02-COMB. DESMI525 02-KOMB. DESMI525 12-COMB. DESMI525 12-KOMB. DESMI525 in 02-Ausführung DESMI525 in 12-Ausführung DESMI620D DESMI620W DESMI625D DESMI6302 2RS1 DESMI6304 2RS1 DESMI6305 2RS1 DESMI6306 2RS1 DESMI6307 2RS1 DESMI6308 2RS1 DESMI630D DESMI6310 2RS1 DESMI6312 2RS1 DESMI6315 2RS1 DESMI65-265/-02 WITH INDUCER DESMIA 2 DESMIA -D11 DESMIA(D)11-02 DESMIA- 1 DESMIA- 2 DESMIA-D11 DESMIA02 DESMIA02-I DESMIA07 excl. elmotor DESMIA07 без электродвигателя DESMIA09 DESMIA11-02 DESMIA11-09 DESMIAM122…C-2 DESMIAM136…D-2 DESMIAM4pol DESMICHD/EPDM DESMICTP 50 DESMICTP 53 DESMICTP 70 DESMIDES 150 P&F – DES 180 P&F DESMIDES 180 P&F DESMIDES 250 P&F DESMIDES 250 P&F – DES 280 P&F DESMIDES 250P - 150F DESMIDES 250P – 150F DESMIDES 265 P&F DESMIDES 265P - 165F DESMIDES 265P – 165F DESMIDES 280 P&F DESMIDES 280P - 180F DESMIDES 280P – 180F DESMIDES 340 - BASIC DESMIDES 340 - FWB DESMIDES 340 – 365 FWB DESMIDES 350 - BASIC DESMIDES 350 - FWB DESMIDES 365 - BASIC DESMIDES 365 - FWB DESMIDES-1 DESMIDL300 DESMIDL300B DESMIDL350 DESMIDL350B DESMIDL400 DESMIDL400B DESMIDL500 DESMIDLS400 DESMIDSL 250-310 DESMIDSL 250-360 DESMIDSL 300-320/DSL 400-430 DESMIDSL 300-430 DESMIDSL 300-495
Pump spare parts
By manufacturer

Manufacturers.

All 179 manufacturers with models of Pump. Names with a manufacturer page open it; the others open a search across the full library.

All manufacturers
Show all 179 manufacturers
Related types

Also in Pumps.

The other equipment types in this category.

Auxiliary Cooling SW PumpBallast PumpBilge Pump (Main + Emergency)Cargo Pump (Deepwell)Centrifugal PumpEjector / EductorFO Circulating PumpFire Pump (Main + Emergency)Freshwater Hydrophore PumpFuel Oil Supply/Booster PumpFuel Oil Transfer PumpGear PumpGeneral Service PumpHT/LT Cooling Water PumpJacket Water Preheater PumpLO Standby/Priming PumpMain Cooling Seawater Pump (Centrifugal)Main Lube Oil PumpProgressive Cavity PumpPulsation DamperScrew PumpSelf-Priming PumpSludge PumpSteering Gear Hydraulic PumpStern Tube LO PumpSubmersible Pump
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