Spare parts for high-pressure pumps and seals
We supply service kits, wear parts and mechanical seals for SWRO high-pressure pumps: Danfoss APP axial piston pumps, and Sulzer and Flowserve multistage centrifugal pumps.
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Danfoss APP axial piston pumps
| Parameter | According to Danfoss |
|---|---|
| APP 0.6 to 10.2 | 14 – 250 m³/day |
| APP 11 to 46 | 250 – 1,000 m³/day |
| APP 53 to 92 | 1,000 – 2,200 m³/day |
| Lubrication | By the pumped medium; no oil |
| Stated efficiency | up to 92% |
| Materials | Duplex, super duplex and ceramic |
| Service interval | up to 8,000 hours; major overhaul up to 25,000 hours |
Source: Danfoss — high-pressure pumps for RO.
Because the pump is lubricated by seawater, upstream filtration decides how long the wear parts last. We supply service kits and wear parts by the code number on the pump nameplate. For systems with iSave, which combines a pressure exchanger with a positive-displacement booster pump, we quote its spares too.
Sulzer and Flowserve multistage centrifugal pumps
Large plants usually get their high pressure from a multistage centrifugal pump, for example an axially split design such as the Sulzer MSD. The parts replaced most often are:
- Wear rings and bushings — wear reduces flow and efficiency.
- Bearings.
- Mechanical seals.
- Casing gaskets and O-rings.
- Impellers, where there is erosion or cavitation.
For these pumps we need the model, serial number and, if possible, the manufacturer's parts list number. Each pump is built to order and the same designation can carry different parts.
Mechanical seals
We supply John Crane, Flowserve and other manufacturers' mechanical seals for high-pressure, feed and booster pumps. Silicon carbide against silicon carbide faces are common in seawater service.
| Symptom | Usual cause |
|---|---|
| Leak soon after installation | Assembly, alignment, or face damage during fitting |
| Scored or heat-checked faces | Dry running or insufficient flow at start-up |
| Rapid abrasive wear | Solids in the fluid |
| Failure after an emergency stop | Pressure spikes or water hammer |
To quote a seal we need the pump model and serial number, or the seal drawing or reference, and the shaft diameter.
Materials
Parts in contact with high-pressure seawater are usually specified in super duplex stainless steel. Pitting resistance is expressed as PREN:
PREN = %Cr + 3.3 × %Mo + 16 × %N
Seawater service commonly calls for PREN of 40 or higher. Where a replacement part is offered in a different material from the original, the quotation says so.
Documents
- Commercial invoice and packing list.
- Distributor invoice or confirmation identifying where the part was bought.
- Manufacturer's certificate of origin where the manufacturer issues one.
- Photos of the parts and their labels before dispatch.
- Air waybill (AWB) or bill of lading (B/L).
Have the equipment nameplate to hand?
Send a photo or the part number. We check the model and reply within 4 business hours.
Related pages
Frequently asked questions
Do you supply Danfoss APP service kits?
Yes, by the code number on the pump nameplate.
Can you quote a mechanical seal without the drawing?
Yes, if we have the pump model and serial number. With the seal drawing the quotation is faster.
Are the parts genuine?
Yes, genuine parts from each manufacturer.