K, L, C and W series screw pumps and OMP flow meters — identified by series letter, sub-type and nameplate, quoted with OEM or verified-alternative evidence.
KRAL GmbH of Lustenau, Austria, founded in 1950, builds screw pumps and screw-type flowmeters. Its marine brochure gives each family a duty — the K series for fuel booster modules, the DKC and DLC double pump stations for boiler supply, K and C for engine and gear lubrication, the two-screw Z series for cargo, tank transfer and bunkering, and C and W for steering gear, propeller pitch and windlass hydraulics — so the family letter tells you the duty before a single dimension is measured.
The universal family, and the one KRAL names for fuel booster modules and for engine and gear lubrication. Nodular cast-iron housing, nitrided steel screws, and an internal safety valve on every K-series pump. The maker's mounting variants are KF and KH (horizontal, KH on a base frame), KV (vertical pedestal) and KFT (overhead DIN flanges), so copy the letters after the K exactly.
A medium-pressure family built on the same nodular cast-iron housing as the K series, for duties that sit above what a K-series unit is rated for without moving to the heavier C-series construction.
The high-pressure family, built in three sub-types on shared main components. CK is the compact build with a short shaft and internal bearings and takes a radial shaft seal ring only; CL has a longer main screw and can take other shaft seals and external bearings; CG is a CL pump fitted as a cartridge into its own cast-iron or steel housing, with a heating jacket and an external overflow valve as options. KRAL names the C series for engine and gear lubrication and for steering gear, propeller pitch and windlass hydraulics. State the sub-type letter, not just "C series" — it decides the shaft, bearings and seal on the parts list.
KRAL names it, alongside the C series, for shipboard hydraulics — steering gear, propeller pitch adjustment and anchor windlass. The running housing carries a polymer coating that can take up particles, the pump is built for dirty or low-viscosity liquids, and it can be installed in the tank (wet) or outside it (dry). Confirm which installation variant is fitted before ordering a housing or coating-sensitive part.
OMP is the series KRAL designs for fuel consumption measurement on ships, and it is also used in booster modules and burner lines. It is a screw-type meter: a pulse sensor counts the screw edges inside a spheroidal graphite iron housing. KRAL builds other meter series under the same OM prefix — OME, OMG, OMH, OMS and OMX — so copy the letters after OM, the size and the pulse sensor's marking from the meter's own plate, not the pump's.
A KRAL designation starts with the series letter and carries the variant after it — KF, KH, KV and KFT on the K series, LFI, LFT, LVI, LVT and LFM on the L series, CK, CL and CG on the C series — followed by a size code. Send it as stamped, in the order it is written, rather than shortened to the series letter alone. Then say how the shaft is sealed — radial shaft seal, mechanical seal or magnetic coupling — because KRAL issues separate operating instructions for each variant (on the K series OIK 07, OIK 14 and OIK 09) and the seal parts follow that choice. Where the plate has worn or been overpainted, the pump's duty (fuel, lube oil, hydraulic, burner) and the pipework connection size narrow the identification considerably, and a photograph of the housing and connection flanges is usually enough for us to work from alongside that.
Tools for this equipment: the mechanical seal material code for a mechanical seal, the oil seal size reader for a radial shaft seal and the flange identifier for the connection flanges. Where the pump handles lubricating oil, the oil viscosity grade converter shows the viscosity range of its ISO VG or SAE grade. For a viscosity given in SUS or in cP rather than cSt, the viscosity units converter brings it to one unit before it is set against the pump rating.
The matched set of driving and idler screws is the core wearing assembly and is renewed as a set rather than by individual screw: the pressure is held by the sealed chambers the meshing screws form with the close-fitting casing bores, so one new screw among worn ones does not restore it.
KRAL seals the drive shaft in one of three ways: a radial shaft seal (an NBR or FKM lip seal), a mechanical seal in standard or hard-material execution, or a hermetic magnetic coupling with no shaft seal at all, and the CK takes the radial shaft seal ring only. Which of the three is fitted decides the seal parts, and the seal type is also specific to the duty — a fuel-duty seal is not necessarily correct for a hydraulic-duty unit of the same series.
On the K and L series the drive screw runs in a sealed, lifetime-lubricated external bearing; the CK has internal bearings and the CL can take external ones. Bearings are renewed alongside the screw set on a full overhaul rather than left in service against a new set.
Every K-series pump has an internal safety valve and the L series a built-in overflow valve; on the CG an external overflow valve is an option. Whichever is fitted, it protects the pump from a blocked discharge, it is a separate wear item from the pump itself, and its setting should be confirmed rather than assumed on renewal.
Flexible coupling elements and drive-end seals, reviewed when the pump is uncoupled for any other overhaul work.
Complete overhaul gasket and O-ring sets for the housing joints, ordered against the full nameplate designation rather than by dimension alone.
Yes, working from the duty, connection size and a nameplate photograph, though the full series, sub-type and size code narrows the identification considerably faster.
Only in part. KRAL builds all three on the same main components and says the differences lie in the details: the CK has a short shaft, internal bearings and a radial shaft seal ring only, the CL a longer main screw with a choice of shaft seals and external bearings, and the CG uses a CL pump as a cartridge inside its own cast-iron or steel housing. A CG and a CL can therefore share the inner pump while a CK differs in shaft, bearings and seal, so send the full designation and each part is checked against it rather than assumed common.
Yes. OMP flow meters are commonly fitted on the same fuel line as the pump and are quoted alongside it, but as a separate line item since the two fail independently.
Both, reviewed case by case against the vessel's timeline, classification requirements and the part in question.
Not necessarily. The seal type is specific to the duty, so a fuel-duty seal is not automatically correct for a hydraulic-duty unit of the same series. State the duty and the pumped liquid together with the full nameplate designation.
No, and there is no agreement of any kind. Vessel Core holds no dealership, distribution, representation or partnership agreement with KRAL, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the KRAL series and sub-type letter (K, L, C or W), the size code and a nameplate photograph, together with the duty and connection size. Vessel Core reviews the supply route and prepares a structured quotation.
