Leistritz Screw Pump
Spare Parts Supplier
Two-, three- and five-spindle screw pumps from Nuremberg for lube oil, fuel, hydraulic and cargo duty — identified by the full type code and the serial number, then quoted by OEM route or verified alternative.
Leistritz screw pump ranges found on board
Leistritz Pumpen GmbH has built screw pumps in Nuremberg since 1924, and its marine programme covers lube oil and fuel oil systems, steering gear and pitch propeller hydraulics, and tanker cargo handling. The ranges are organised by the number of spindles and the casing layout rather than by duty, so the same range turns up on a lube oil skid and on a cargo pump. The range is where identification starts, not where it ends.
L2 range
Two spindles in a single-volute casing, carried in bearing bushes at both ends and hydraulically balanced, with one shaft seal and no timing gears. Leistritz lists shipbuilding duties from main lube oil and fuel oil service to transfer, control, hydraulic and ship loading and unloading. The L2NG is the cased pump; the L2NT is the semi-submerged cargo version.
L3 range
Three spindles for non-abrasive lubricating fluids. The L3NG serves lube oil, transfer, hydraulic, circulating and fuel duty on diesel engines, compressors, turbines and gearboxes, and Leistritz also builds L3NG main lube oil pumps flanged directly onto large diesel engines and driven from an engine gear. The L3NT is the submerged main lube oil pump for two- and four-stroke engines, with an immersion tube and a cardan shaft.
L3MF
The three-spindle pump Leistritz names for steering gears, controllable pitch propellers and winches. On these units the steering gear or propeller maker's documentation matters as much as the pump's own plate, because the pump was chosen to suit that system.
L4 range
Two screws in a double-volute casing, each spindle made in one piece, held apart by herringbone timing gears, with the gears and ball bearings running in their own oil and a replaceable casing insert. The 4 is a range number, not a spindle count: an L4 brings timing gears, more bearings and more shaft seals onto the parts list than an L2.
L5 range
Five screws in a single volute for low-pressure duty, with axially balanced rotors and one shaft seal. In Leistritz's maritime literature the five-screw design, alongside the two-screw, is the cargo pump for unloading and stripping tankers.
FLEXCORE
A newer Leistritz design in which the pump core is a cartridge changed as one unit, and the pump mounts vertically or horizontally. Leistritz positions it for fuel and lube oil service on board, in nodular cast iron or steel casings, with either a magnetic drive or a single mechanical seal.
Where a Leistritz pump loses its clearance
On the L2 range Leistritz carries both spindles in exchangeable bearing bushes at each end, and states that the spindles stay clear of the bore as long as the pump is kept within its rated delivery pressure. The bushes double as throttling points between suction and discharge and are lubricated by the pumped fluid itself. That puts the bushes, not the spindles, at the front of the wear sequence: the pump that marks its bore is usually the one that ran on worn bushes or against a closed discharge.
The three-spindle L3 range is built for non-abrasive lubricating fluids. Catalyst fines, tank scale or weld debris left after a pipework repair are outside that design brief, and they mark the spindle flanks and the casing bore together, which is why the spindle set and the condition of the casing belong in the same request.
Engine-mounted L3NG main lube oil pumps are driven from an engine gear and carry no shaft seal at all. The items that matter move to the drive gear and the bearings, and a request that opens with a seal kit has started in the wrong place.
Leistritz describes the L4 as a non-contacting design: the timing gears keep the spindles apart, and gears and ball bearings run in their own oil. On an L4, the condition of that bearing oil and the wear on the gear teeth are the first things to look at, before the insert is condemned.
Leistritz pump components that go on an enquiry
The groups follow the way a Leistritz pump comes apart — rotating set, bearing bushes, casing and insert, shaft sealing, bearings and drive, valve — so each line can carry the item number from the pump's sectional drawing beside its description.
- Spindle sets — drive spindle with its idler spindle or spindles, matched by size and pitch
- Bearing bushes for drive and idler spindles, in the material pairing the pump was built with
- Casing inserts on L4 pumps and steel-welded executions
- Exchangeable FLEXCORE cartridges
- Mechanical seals — single or double, component or cartridge type
- Stuffing box packing and packing followers on cargo pumps; throttle bushes on submerged units
- Magnetic coupling assemblies on sealless executions
- Rolling bearings, internal or external according to the option code
- Timing gears and bearing-oil parts on L4 pumps
- Drive gears on engine-mounted main lube oil pumps
- Relief and safety valve internals, with or without handwheel
- Immersion tubes and cardan shafts on L3NT submerged pumps
- Column shafts, threaded shaft couplings and gear-drive heads on L2NT cargo pumps
- Casing gaskets and O-rings in FPM or NBR
- Flexible spacer couplings and baseplate items on skid-mounted units
Reading a Leistritz type code before the request goes out
Leistritz writes its type code in a fixed order: the range (L2, L3, L4 or L5), a pressure letter (N for low, M for medium, H for high), a design letter (G for the standard cased pump, T for the submerged version, other letters for special executions such as the L3MF), then the size and the pitch of the drive screw written as a pair, a block of option letters, and finally the shaft-sealing letter. The meaning of the option and seal letters is set range by range — on an L2NG the last letter separates a mechanical seal, a radial seal, no seal and a magnetic drive, while on a submerged unit it describes the seal above the tank plate. One size is built in more than one pitch, so copy the whole string exactly as it is stamped.
- Complete type code as stamped, including the size and pitch pair and every option letter
- Serial number — the reference Leistritz itself asks for when spare parts are ordered
- Where the pump sits: on the engine, on its own skid, in a tank or in a cargo barrel, and which system it serves
- Engine maker and type for an engine-mounted lube oil pump, since its connection geometry was made to the engine builder's requirement
- Driver: electric motor, hydraulic motor or engine gear, with the motor plate where the motor is separate
- Rated capacity, differential pressure, speed and viscosity exactly as they appear on the plate
- Pumped medium and its service temperature — lube oil, heavy fuel, distillate, hydraulic oil or cargo grade
- Shaft sealing visible on the pump: mechanical seal, packing, magnetic drive or none
- Class certificate or works test certificate supplied with the pump, if the replacement must carry the same paper
- Photographs of the plate taken square-on and of the pump in place, showing the ports and the mounting
Tools for this equipment: the mechanical seal material code for the seal faces and the flange identifier for the suction and discharge flanges. The oil viscosity grade converter gives the viscosity range of the ISO VG or SAE grade a lubricating oil pump is handling. If the pump data give the viscosity in Saybolt seconds, the viscosity units converter turns the figure into cSt at the same temperature.
How a Leistritz line is routed
Leistritz works its own spares from the pump's serial number, and Vessel Core reads every enquiry the same way before a route is chosen. What decides between the OEM route and a verified alternative is the part, not the brand on the casing.
Matched parts stay on the maker's reference
Spindle sets, bearing bushes, casing inserts and FLEXCORE cartridges are finished to one another and to the casing, so they are quoted against the serial number on the OEM route unless the buyer's own documentation allows otherwise.
Standard items can be cross-checked
Mechanical seals built to a recognised standard, O-rings, rolling bearings and coupling elements can be examined against a verified alternative once the seal design and the elastomer grade are confirmed from the plate or the parts list.
Class paper is settled first
Leistritz issues class approval certificates and works test certificates where a project calls for them. If the original pump came with such paper — a steering gear pump or a main lube oil pump, for example — say so at the start, because it narrows the route.
Engine-mounted pumps follow the engine
A gear-driven lube oil pump flanged to the engine is ordered with the engine maker and type beside the pump code, because its flange and connections were made to suit that engine.
Cargo pumps are read as a column
On an L2NT cargo pump the pump end, the column shafts and their couplings, the packing or seal at the discharge head and the gear drive are separate lines, so the request can say which part of the column has been opened.
Leistritz screw pump parts — common questions
Can a Leistritz pump part be quoted from the type code alone?
The type code describes how the pump was built, but Leistritz itself matches spare parts to the serial number and to where the pump is installed. Send both; where the plate is unreadable, photographs of the pump in place, its ports and its shaft sealing usually narrow the identification considerably.
Does the digit after the L give the number of spindles?
For the L2, L3 and L5 ranges it matches — two, three and five. The L4, however, is a twin-screw double-volute pump with timing gears, so read the range as a whole rather than counting spindles from the digit.
Is an engine-mounted Leistritz lube oil pump ordered the same way as a separate motor-driven one?
No. Engine-mounted L3NG main lube oil pumps are flanged to the engine, driven from an engine gear and built without a shaft seal, with connections made to the engine builder's requirement. Give the engine maker and type together with the pump plate; the drive gear and the bearings matter more here than any seal kit.
What is replaced on a FLEXCORE pump?
The exchangeable pump core — the cartridge — as one unit. The cartridge and any casing or drive parts are quoted as separate lines, and the request should state whether the pump has a magnetic drive or a mechanical seal.
Are Leistritz cargo pumps on deck handled as well as engine-room pumps?
Yes. An L2NT semi-submerged cargo pump hung in a barrel in the cargo tank is read against the same type code, with the pump end, column shafts and threaded couplings, the packing or mechanical seal and the gear drive as separate lines. State whether it is driven by an electric or a hydraulic motor.
Is Vessel Core connected to Leistritz?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Leistritz, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the type code and the serial number.
Copy the Leistritz type code exactly as stamped, add the serial number, where the pump is installed and what it pumps, then list the parts needed and the port. Vessel Core reviews the supply route and replies with a structured quotation.
