51.0401.09 InterpumpGroup W1210 Piston D. 18x25: Complete Buyer's Guide for Worldwide Sourcing
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The 51.0401.09 InterpumpGroup W1210 piston D. 18x25 is a factory-spec reciprocating piston (plunger) for Interpump W-series high-pressure pumps, sized 18 mm diameter x 25 mm stroke. It restores pressure and flow in pumps rated around 200 bar (20 MPa / 2,900 psi) at 1,750 rpm, and is sourced worldwide as a maintenance wear part rather than a complete pump.
What is the 51.0401.09 InterpumpGroup W1210 Piston D. 18x25?
A 51.0401.09 InterpumpGroup W1210 piston D. 18x25 is a precision-ground reciprocating plunger used inside Interpump W-series high-pressure pumps, with an 18 mm diameter and 25 mm stroke. It converts rotary motor input into linear pressure pulses, and is replaced when wear causes pressure loss, cavitation noise or seal leakage.
Interpump Group is one of the world's largest manufacturers of high-pressure reciprocating pumps, supplying OEM and aftermarket parts across agriculture, industrial cleaning, reverse osmosis and process industries. The W1210 designation identifies the pump family; the 51.0401.09 code identifies the specific piston variant.
How does a W1210 piston work inside an Interpump pump?
The piston reciprocates inside a ceramic or hardened-steel liner, drawing fluid through an inlet valve on the suction stroke and forcing it through a discharge valve on the pressure stroke. Seals and O-rings isolate the piston from the pumped fluid.
Because the piston is a wear item, its diameter (18 mm) and stroke (25 mm) directly determine displaced volume per revolution — and therefore the pump's rated flow. Substituting a different diameter changes flow and pressure characteristics, so always match the OEM code.
Key specifications at a glance
| Parameter | Value | Notes |
|---|---|---|
| Piston diameter | 18 mm | Nominal, matched to W1210 liner |
| Stroke | 25 mm | Fixed by crankshaft geometry |
| Pump flow (reference) | 15 L/min (3.96 US gpm) | At rated rpm |
| Operating pressure | 200 bar (20 MPa / 2,900 psi) | Continuous duty reference |
| Rotation regime | 1,750 rpm | 50 Hz motor; ~1,450–1,750 rpm typical |
| Reference power | 5.73 kW (7.8 hp) | Pump-side rating |
| Reference weight (pump) | 9.5 kg | Complete pump assembly |
| Reference dimensions | 273.5 x 223 x 152.5 mm | Complete pump envelope |
Note: the values above describe the reference W-series pump configuration. Confirm the exact piston code against your pump nameplate before ordering.
Which Interpump pump families use this piston?
The W1210 piston is used across Interpump W-series plunger pumps in industrial cleaning, agriculture spraying, misting and reverse-osmosis duty. Related Interpump pump families in the 3G Electric catalog include the T-series and TS-series, which share many service parts and accessories.
If you are replacing a complete pump rather than a piston, the Inter[[PRODUCT:T01321-000|pump T1321 and Inter[[PRODUCT:TS1331-000|pump TS1331 are common drop-in alternatives for lower-flow duties, while the Interpump T2830Y SX Pump with 53R Motor covers higher-flow, higher-power applications.
Types and applications in Worldwide markets
Interpump W-series pistons are deployed worldwide in three broad duty classes:
- Light duty — mobile cleaning, misting, low-hour agriculture spraying (intermittent, <500 hours/year).
- Medium duty — industrial washdown, car wash, food processing (1,000–2,000 hours/year).
- Heavy duty — reverse osmosis, descaling, continuous process (2,000+ hours/year, often 24/7).
In export markets, buyers frequently request 50 Hz and 60 Hz variants of the same pump so the piston and seal kit remain interchangeable across regions. Confirm motor frequency when ordering a complete pump, but the piston itself is frequency-independent.
How to select the right piston and pump combination
- Identify the pump model from the nameplate (e.g. W1210, T-series, TS-series) — the piston code is family-specific.
- Confirm piston diameter and stroke (18 mm x 25 mm for this part) against the OEM parts diagram.
- Match flow and pressure to your process — 15 L/min at 200 bar is the reference point for this piston.
- Check seal and valve kit compatibility — replace seals, O-rings and valves at the same time as the piston to avoid repeat teardown.
- Verify duty cycle and fluid — abrasive or hot fluids shorten piston life; specify ceramic or hardened variants where offered.
- Confirm motor frequency and voltage for the drive side (50 Hz vs 60 Hz affects rpm and therefore flow).
- Plan spares stock — for continuous duty, hold at least one spare piston and seal kit per pump.
Product selection ladder: Interpump pumps and spares
| Model | Flow | Pressure | Power | Typical duty |
|---|---|---|---|---|
| Inter[[PRODUCT:TS1331-000|pump TS1331 | 13 L/min | 120 bar (12 MPa / 1,740 psi) | 2.94 kW (3.9 hp) | Light duty, 1,450 rpm |
| Inter[[PRODUCT:T01321-000|pump T1321 | 15 L/min (3.96 US gpm) | 200 bar (20 MPa / 2,900 psi) | 5.73 kW (7.8 hp) | Medium duty, 1,750 rpm |
| Inter[[PRODUCT:T09281S0U-000|pump T9281 L | 15 L/min (3.96 US gpm) | 200 bar (20 MPa / 2,900 psi) | 5.73 kW (7.8 hp) | Medium–heavy duty |
| Interpump T2830Y SX Pump with 53R Motor | 30 L/min (7.92 US gpm) | 275 bar (27.5 MPa / 4,000 psi) | 15.44 kW (21 hp) | Heavy duty, 1,750 rpm |
| Inter[[PRODUCT:AB0150CD-000|pump AB150 PTO R | PTO-driven | Up to 150 bar class | PTO-driven | Agriculture / tractor PTO |
Step up the ladder when your duty cycle exceeds 2,000 hours/year, when you need higher pressure for reverse osmosis or descaling, or when a single pump must serve multiple outlets. Step down when portability, low power draw or intermittent use dominates.
Accessories and service parts to order together
Pair the piston replacement with the Interpump 56C Flexible Coupling to protect the motor and pump from misalignment, and the Interpump VarioJet Kit with 125 Nozzle for adjustable spray control. For foam-based cleaning, the Interpump FoamKit 3 for T/TX Series Pumps integrates directly with T-series and TX-series pumps.
According to Interpump Group S.P.A. technical datasheet SS3C2015 (dated 3/21/2026): "Male shaft (key) - (plugs) - OUT OF PRODUCTION." Buyers should confirm current shaft and piston variants with their supplier before ordering legacy configurations.
Why source from 3G Electric
3G Electric stocks 4,007+ products across 14 industrial departments — from pumps and combustion to controls, instrumentation and power transmission — and supplies far more than is listed online. With 35+ years of experience, we interpret your demand, confirm the correct Interpump piston or pump variant, and quote it with export-ready documentation for Worldwide delivery.
We are a distributor and supplier — not an authorized dealer — for the brands we carry, which means we are accountable for getting you the right answer, not just the closest SKU. Our specialist depth in pumps, combustion and controls is a trust anchor, not a limit on what we can source.
Frequently asked questions
What is the 51.0401.09 InterpumpGroup W1210 piston D. 18x25 used for?
It is a replacement plunger for Interpump W-series high-pressure pumps, restoring flow and pressure in cleaning, agriculture and reverse-osmosis duties. It is an 18 mm diameter x 25 mm stroke wear part, typically rated around 200 bar (20 MPa / 2,900 psi) at 1,750 rpm.
How do I know if my pump needs a new piston?
Common signs are falling discharge pressure, pulsation, cavitation noise, water in the oil, or visible scoring on the piston surface. If pressure drops more than 10–15% at the same rpm and nozzle, replace the piston and seal kit together.
Can I use a different piston diameter in the same pump?
No. Piston diameter and stroke are matched to the pump's crankcase and liner. Changing diameter alters flow and pressure and can damage valves and seals. Always order the OEM code (51.0401.09 for the 18x25 variant).
Do you ship Interpump spares worldwide, and what about lead time?
Yes. 3G Electric supplies Worldwide with export documentation, incoterms-neutral shipping and cross-market 50 Hz / 60 Hz variants. Lead time depends on stock status — in-stock items typically ship within days; special-order pistons may take longer. Request a quote for current availability.
What is the difference between the W1210 piston and a complete Interpump pump?
The piston is a single wear part inside the pump. A complete pump such as the Interpump T1321 includes the crankcase, valves, seals and manifold. Replace the piston for maintenance; replace the pump when the crankcase or manifold is worn.
Which accessories should I order with the piston?
Order a seal kit, O-rings, inlet/outlet valves and a flexible coupling such as the Interpump 56C Flexible Coupling at the same time. This avoids a second teardown and protects the motor from misalignment.
Key takeaways
- The 51.0401.09 InterpumpGroup W1210 piston D. 18x25 is an 18 mm x 25 mm plunger for Interpump W-series pumps, rated around 200 bar (20 MPa / 2,900 psi) at 1,750 rpm.
- Always match piston code, diameter and stroke to the pump nameplate — never substitute a different size.
- Replace seals, O-rings and valves at the same time as the piston to avoid repeat downtime.
- Confirm 50 Hz vs 60 Hz motor variants for export orders; the piston itself is frequency-independent.
- 3G Electric supplies Interpump pumps, spares and accessories worldwide with export documentation and technical support.
Get a quote from 3G Electric
Contact 3G Electric for pricing, sizing assistance and technical support on the 51.0401.09 InterpumpGroup W1210 piston D. 18x25 and the full Interpump pump range. Send us your pump nameplate details, required flow and pressure, and destination country — we will confirm the correct part and quote it with Worldwide delivery.
