Metering Pump Model Number Explained: How to Decode Every Field

A metering pump model number is a compressed spec sheet: series, rated flow, maximum pressure, wetted material group, power supply and control mode, usually in that order. Once you can split the code and cross-check it against the data sheet columns, ordering the wrong pump becomes very hard. This guide is written for buyers, design engineers and maintenance teams reading a catalog for the first time, and it covers solenoid and mechanical diaphragm dosing pumps.

What order do the fields in a metering pump model number follow?

Every manufacturer has its own format, yet the logic is similar. Take the example printed in the NEWDOSE mechanical diaphragm pump selection manual, NDWL-410-0.6-PVT-A-I:

1. NDWL is the series. Pumps in one series share the gearbox and drive design.
2. 410 is the rated flow in L/h.
3. 0.6 is the maximum discharge pressure in MPa, which is 6 bar.
4. PVT is the wetted material group.
5. A is the motor: a standard three-phase 380V motor. AVF means a variable frequency motor, AEX an explosion-proof motor, and B a single-phase 220V motor.
6. I is the capacity control. H means manual stroke adjustment, I means an electric stroke actuator.

Solenoid pumps use shorter codes. In NEWDOSE DFD-02-16, DFD is the manual stroke-rate model, 02 is 2 L/h and 16 is 16 bar. Notice the trap: the solenoid code states pressure in bar while the mechanical code uses MPa. Both sit in the same catalog, and mixing them up is the most common reading error we see.

The material code covers more than the pump head

Many buyers read PVT as "PVC head" and stop there. In the NEWDOSE manual, PVT actually means a PVC head, PTFE diaphragm, PTFE valve seats, ceramic balls and FKM seals. SST means SS316 head, seats and balls. When you check chemical compatibility, check the whole group. The O-ring material is often the weak point, not the head.

Iwaki writes its codes differently. In a metering pump model number starting with EHN-BN11VC, BN is a drive unit with about 20W average power (CN is 24W), 11 means a 10mm effective diaphragm diameter and VC is the wetted material code. Suffixes then tell you the controller (R standard, YN advanced) and special versions such as NAE auto-degassing or H high pressure. Our Iwaki EHN model code breakdown walks through every position.

How to read the metering pump data sheet columns

A data sheet row repeats the metering pump model number and then spreads the performance out. Here is the NEWDOSE NDWS-18/1.6 row:

• Flow 18 L/h at 16 bar. This is the maximum flow at maximum pressure, typically measured with clean water.
• Stroke length 2mm, which is how far the diaphragm travels on each stroke. Adjusting capacity on a mechanical pump usually means setting this as a percentage.
• Diaphragm diameter 60mm. A bigger diaphragm moves more liquid per stroke.
• Stroke rate 118 SPM, the number of strokes per minute.
• Displacement 2.54 ml per stroke, with a 180 W motor.

A quick sanity check: ml per stroke × SPM × 60 ÷ 1000 should land close to the L/h figure. 2.54 × 118 × 60 ÷ 1000 is about 18, so the row is consistent. If your own math is far off, ask the supplier before you order.

Extra columns on solenoid pump tables

A solenoid metering pump model number is shorter, and its table usually adds suction lift and weight. The NEWDOSE DFD series lists a 2 m maximum suction lift. That figure assumes ideal conditions; viscous, warm or gassy chemicals cut it down quickly, so flooded suction is safer whenever the layout allows it. Stroke rate on DFD models is 120, 160 or 240 per minute, and the faster models generally trade pressure for flow.

Four places where a metering pump model number gets misread

Rated flow is not running flow. The number is taken at full stroke, full speed, clean water and room temperature. Most engineers size around 30% above the maximum required dose.

Pressure units vary. MPa, bar and kgf/cm² all appear on site. 1 MPa is about 10 bar, so "6 kg" is roughly 0.6 MPa.

Supply frequency matters. On a mechanical pump the stroke rate follows motor speed, so the same metering pump model number delivers different flow on 50Hz and 60Hz grids. Confirm the local grid for export projects.

Some codes are not in L/h at all. The Cheonsei KD series encodes flow as two digits converted with A×10^B ml/min; see how to read Cheonsei KD flow codes.

A checking order that works

When you shortlist a metering pump model number, fix pressure first, then flow, then materials, and leave power supply and control for last. A pump that cannot reach line pressure is useless no matter how well the flow fits. Wrong materials leak within days. Control depends on what signal you have: a manual model cannot follow a 4–20mA loop from a DCS. Compare pump types in our metering pump product range, and see the full series list on the NEWDOSE brand page.

Conclusion

Reading a metering pump model number comes down to a fixed pattern: series, flow, pressure, materials, power, control. The data sheet adds stroke length, stroke rate, diaphragm size and motor power. Before you sign off, confirm three things: whether pressure is in bar or MPa, what every part of the material code covers, and the test conditions behind the rated flow. If you are unsure, send us the chemical, concentration, temperature, flow and discharge pressure, and contact our engineers to check the metering pump model number field by field.

FAQ

Is the flow in the metering pump model number what I will actually get?

Not exactly. It is measured at full stroke and speed with clean water, so viscous chemicals or high back pressure reduce it.

What is the difference between stroke length and stroke rate?

Stroke length is how far the diaphragm moves each time; stroke rate is how many times per minute. Together they set the output.

Why are there several models for the same flow?

They combine pressure, diaphragm size and stroke rate differently. High pressure models usually have smaller diaphragms and shorter strokes.

What if I cannot decode the material code?

Look up the material table in the catalog and match head, diaphragm, seats, balls and seals. If it is not listed, follow the manual for that model.

Can I swap an imported pump for a local one by matching codes?

No. Each brand writes its metering pump model number with its own rules, so compare flow, pressure, connections and footprint, and ask the supplier for a cross-reference.