Spare Parts for
GEA Westfalia Separators
Bowl, regulating ring and operating water components for OSA · OSC · OSD · OSE machines
Westfalia separator families and what changes between them
GEA Westfalia Separator centrifuges are fitted as fuel oil purifiers, fuel clarifiers, lube oil purifiers and sludge treatment machines across fuel oil, lube oil and sludge duty on both newbuild and second-hand tonnage. The families below share a common self-cleaning bowl principle but differ in bowl diameter, disc count, discharge arrangement and interface control, so the size and build digits in the type designation matter as much as the family letters.
OSD series
The workhorse marine purifier line — sizes such as OSD 6, OSD 18 and OSD 35 handle heavy fuel and lube oil duty with a hydraulically actuated sliding piston and a full bowl-periphery solids ejection.
OSE series
Separators covering the sizes OSE 5, OSE 10, OSE 20 and OSE 40, with bowl internals and the operating water block differing from the OSD equivalents even where the throughput rating looks similar.
Clarifier configuration
Clarifier configuration closes off the heavy-phase outlet with a clarifier disc or sealing ring in place of the regulating ring, and uses a different top disc. OSD and OSE bowls are rigged both ways, so state whether the machine is currently running as clarifier or purifier — the bowl parts differ between the two.
unitrol / unitrolplus
These systems replace the regulating ring altogether, holding the oil–water interface in position electronically from a water-content transducer signal, and they also handle discharge timing, water feed and alarms. Sensors, solenoid pilot valves and the transducer itself are the parts most often requested from this side of the machine.
eagleclass
A GEA marine separator class designation that appears on the plate alongside the type code — read as a marine separator eagleclass, type OSE 20, for instance. Quote it together with the type designation rather than in place of it, and note the hardware and software revision recorded in the machine file where a control input is involved.
OSA / OSB / OSC bowls
Earlier self-cleaning bowl generations still in service on smaller auxiliaries. Bowl discs, lock rings and spindle parts for these often need identification from the stamped bowl marking rather than a catalogue reference.
Worm gear drive
Horizontal shaft, worm and worm wheel, friction coupling pads and the vertical spindle. Ratio and worm wheel tooth count vary with bowl speed, so drive parts are machine-specific rather than family-wide.
Discharge system
Sliding piston, closing chamber, nozzles and the operating water valve block. This subassembly is where most partial-discharge and bowl-not-closing complaints originate.
What actually wears on a Westfalia bowl
Six subassemblies account for almost every Westfalia bowl request, and each one is identified from different evidence — a stack height, a stamped hood marking, a fuel density figure. The groups below set out what is worth measuring or photographing before the request leaves the ship.
Disc stack and bowl discs
The stack is a matched set. Disc count, caulk height and total stack height determine how the lock ring seats and how much compression the stack carries. Mixing new discs into a worn stack gives uneven caulk spacing and an altered stack height, disturbing flow distribution between the discs and the compression the lock ring applies. A stack worn throughout instead loses height and leaves the bowl short of correct clamping. Record the number of discs removed and the measured stack height before ordering.
Bowl bottom, bowl hood and lock ring
Erosion at the solids ports and fretting on the lock ring thread are the usual findings on high-hours heavy fuel machines. These are heavy rotating parts machined as a balanced group — the stamped marking on the hood and the machine number must both appear on the RFQ.
Regulating ring (gravity disc)
On conventional purifiers without unitrol interface control, the regulating ring bore sets the position of the oil–water interface in the bowl. Too large a bore moves the interface outward toward the bowl periphery, breaking the water seal and losing oil to the water side; too small a bore moves it inward, letting water carry over into the clean oil. Denser fuel, a higher separating temperature or a lower throughput all point toward a smaller bore. The correct figure follows from fuel density at 15 °C, separating temperature and actual throughput, not from what was fitted last time.
Operating water valve and seal rings
Bowl opening and closing depend on clean operating water at the right pressure reaching the closing chamber. A scaled valve seat or a perished sliding piston sealing ring leaves a bowl that will not close after discharge. An eroded or enlarged nozzle bleeds closing water away faster than it is replaced, giving continuous leakage at the solids ports or discharges that fire without command; a blocked nozzle traps closing water and leaves a bowl that will not open at all.
Spindle, top and bottom bearings
Rising vibration and a changed run-up time are the early signs. The top bearing sits in its damping assembly with springs or elastic elements that must be renewed together with the bearing; the bottom bearing is matched to the spindle seat. Bearing renewal without checking bowl balance rarely cures the vibration on its own.
Gear parts and coupling elements
Worm wheel and worm shaft wear shows as noise, metal in the gear oil and a slow rise to bowl speed. Friction coupling pads glaze and slip. Gear oil condition and the recorded run-up time are useful evidence to include when these parts are requested.
Westfalia separator items quoted from RFQ evidence
Groups routinely appearing on Westfalia purifier and clarifier requests, grouped by where they sit in the bowl and drive, so a partial request can be completed from the neighbouring items.
- Bowl disc sets & individual bowl discs
- Bowl hoods, bowl bottoms & lock rings
- Sliding pistons & closing chamber parts
- Regulating rings (gravity discs) selected by bore
- Operating water valves & nozzle inserts
- Seal ring sets & bowl O-ring kits
- Spindle assemblies, top & bottom bearings
- Damping springs & elastic bearing elements
- Worm wheels, worm shafts & coupling pads
- Distributors, top discs & paring devices
- Solids discharge sensors & control inputs
- Feed and discharge pump wear components
Reading a Westfalia designation before anything is quoted
The type designation on the frame plate carries the family letters, the size figure and further build digits — a machine may read OSD 18-91-067. Those trailing digits change bowl internals between machines that otherwise look identical on the plating. Send the full designation, the machine number, rated throughput, bowl speed and year of build, and add the fuel density and separating temperature whenever the request touches the regulating ring.
Westfalia and Alfa Laval bowls are not interchangeable
A mismatched gravity disc seats badly enough to run, then loses oil to the water side or passes water into clean oil until someone measures the interface. The cost of the wrong disc is discovered downstream, which is why bowl parts are quoted against the Westfalia machine identity alone.
Size figure is not the whole identity
Two machines sharing a size figure can still take different disc counts and different piston seals depending on build revision. Where the plate is painted over or corroded, stamped markings on the bowl hood, the lock ring and the spindle nut usually let the identity be reconstructed.
Regulating ring requests need three numbers
On machines that select the interface with a ring rather than unitrol interface control: fuel density at 15 °C, the temperature the oil is actually separated at, and the throughput the machine is run at. With those three figures the required bore can be checked against the maker's selection chart for that machine size, and a set of neighbouring bores can be considered when bunker quality varies between ports.
Photographs carry more than part lists
A shot of the frame plate, a shot of the stamped bowl marking and a shot of the failed component answer more questions than a typed description. Where a control unit input is involved, the displayed alarm text and the sensor tag from the wiring list are worth adding.
Symptom notes speed up the review
Continuous leakage at the solids ports, water carry-over to the clean oil side, a discharge that fires unbidden, or a run-up time that has crept upward each point toward a different subassembly. A line of description often narrows a request from a full overhaul kit to two or three items.
Time the parts to the bowl opening, not the ETA
A bowl overhaul is planned work, so the useful question is whether the disc stack and seal set land before the machine is opened, not how fast a single item can move on its own. Send the planned opening date with the request. Freight arrangement, documentation, handover option and commercial terms are settled in the written quotation. Read the how we work outline for the sequence.
Maker context
Named to identify the machine, nothing more.
Maker names help identify equipment and prepare an RFQ. They do not imply that Vessel Core is an authorised dealer, representative or partner of the manufacturers named on this page. OSA, OSC, OSD, OSE, unitrol, unitrolplus and eagleclass are GEA designations, used here so the right bowl parts can be identified. See the full maker reference list for the same context across other equipment.
Westfalia separator parts — questions we get
Can a gravity disc or disc stack from an Alfa Laval separator be fitted to a Westfalia bowl?
No. The two makers use different bowl geometry, different disc angles and caulk spacing, and different gravity disc seat and bore dimensions. A gravity disc or bowl disc set intended for an Alfa Laval purifier will not seat correctly in a Westfalia OSD or OSE bowl, and the reverse is equally true. Bowl parts must be quoted against the Westfalia machine type and machine number, never against a cross-maker equivalence table.
What nameplate data is needed to identify Westfalia separator parts?
The full type designation including its build digits, for example OSD 18-91-067, the machine number stamped on the frame plate, the rated throughput, the bowl speed and the year of build. Where the machine is fitted with a regulating ring rather than unitrol interface control, add the fuel density at 15 °C, the separating temperature and the actual throughput being run, because the bore is selected from those three values.
Which Westfalia separator wear items are most often requested for marine RFQs?
Common items are complete disc stacks and individual bowl discs, bowl hood and bowl bottom seal ring sets, the sliding piston sealing ring, regulating rings selected by bore, operating water valve components, spindle top and bottom bearings with their damping elements, worm wheel and worm shaft gear parts, and solids discharge system sensors and control unit inputs.
Can Vessel Core work from a photograph if the Westfalia part number is missing?
Often yes. A clear photograph of the frame nameplate, the stamped marking on the bowl hood or lock ring, and the damaged component itself is usually enough to begin identification against the machine type. Where the item is a matched set, such as a disc stack, the number of discs and the measured stack height should be recorded before the RFQ is sent.
Send the plate, then the parts list.
Give us the type designation and machine number, the component group, the quantity, and the port with the vessel's expected arrival. If the machine uses a regulating ring rather than unitrol interface control, add fuel density and separating temperature. Vessel Core checks the designation against the bowl component groups above and comes back with bore, seal-set and stack-height detail set out line by line in the written quotation.
