Qingdao Nuodean Pump Co Ltd — air operated double diaphragm pumps since the DP series
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Nuodean pump solution: pump selection and sizing
Solution

Select The Right AODD Pump For Your Duty

Choosing a pump based on pipe size or an old model code leads to underperformance, early failure, or unnecessary air use. The right pump matches the duty, not the installation.

Send Us Your Duty Browse Pumps
Why It Matters

Why Sizing Is Based On Duty, Not Pipe Size

A pump selected by pipe size often ends up oversized or undersized for the actual flow and pressure. The DP3X series is sized to match your real duty, not the spool. Port size is chosen by flow and solids handling, not by the flange on the pipe.

What You Should Get From Proper Sizing

  • The pump delivers the required flow at your discharge head without overworking the air supply
  • Port size matches the flow and solids, not the pipe thread or flange
  • Body and elastomer materials are chosen for the fluid, not copied from a nameplate
  • Air consumption is within the capacity of your existing compressor
  • The pump is not oversized, so it uses less air and runs cooler
  • The selection includes the correct repair kit for the chosen materials
Front view of an industrial double diaphragm pump with black manifold and silver chambers.
Step By Step

How We Size Your Pump

Four steps to the right model code, starting with your duty data.

  1. Provide Flow, Discharge Head, Fluid And Air Pressure

    Problem. Without the actual duty, the pump may be too small for the flow or too large for the pressure, leading to poor performance or early failure.

    How we solve it. Send the required flow in GPM or LPM, the discharge head in meters or psi, the fluid type, and the available air pressure in bar or psi. We use this to select the correct pump size and model.

  2. Choose The Right Port Size Based On Flow And Solids

    Problem. Using the same port size as the pipe leads to clogging or reduced flow, especially with solids or viscous fluids.

    How we solve it. We calculate the required port size from your flow and solids size. For example, 50 mm solids require a 3 inch port. A 1 inch port is only for low flow and clean liquids.

  3. Match Body And Elastomer Materials To The Fluid

    Problem. Using the wrong material causes rapid diaphragm or ball failure, especially with acids, solvents, or shear-sensitive fluids.

    How we solve it. We select body material - aluminum, stainless steel, or plastic - and elastomers - NBR, EPDM, or PTFE - based on the fluid's chemical properties and temperature.

  4. Verify Air Supply Limits Flow And Pressure

    Problem. A pump that works at 8 bar may not deliver the required flow at 5 bar, leading to underperformance.

    How we solve it. We check your available air pressure against the pump's performance curve. If the air supply is low, we may recommend a smaller pump or adjust the model code to match your real conditions.

Pumps Involved

Pumps Commonly Selected For Correct Sizing

Front view of a black industrial double diaphragm pump with red ports on a white background
DP3X Series

1 Inch Aluminum Air Operated Double Diaphragm Pump

133 LPM and 8.3 bar from an 8.6 kg aluminum body. The compact workhorse of the DP3X range.

View Specifications →
Front view of an industrial double diaphragm pump with black manifold and silver chambers.
DP3X Series

1-1/2 Inch Aluminum Air Operated Double Diaphragm Pump

340.7 LPM and 8.3 bar from a 23.4 kg aluminum body. The mid-range volume pump in the DP3X series.

View Specifications →
Front view of a black industrial double diaphragm pump with red caps and green accents.
DP3X Series

2 Inch Aluminum Air Operated Double Diaphragm Pump

651 LPM and 8.3 bar from a 29.6 kg aluminum body. The volume workhorse of the DP3X range.

View Specifications →
Front view of a pneumatic double diaphragm pump with black manifolds and silver diaphragm chambers
DP3X Series

3 Inch Aluminum Air Operated Double Diaphragm Pump

897 LPM and 8.3 bar from a 49.8 kg aluminum body. The largest volume pump in the DP3X range.

View Specifications →
Related Guides

Guides Worth Reading First

Working Principle

How An Air Operated Double Diaphragm Pump Works

Follow one full stroke through the pilot valve, the major air valve and both liquid chambers, and the rest of the pump stops being mysterious.

 Buying Guide

How To Size An Air Operated Double Diaphragm Pump

Sizing an air diaphragm pump from the existing pipe size or the headline maximum flow guarantees poor performance. Here is how to select the right displacement and port size from actual duty conditions.

 Material Guide

Aluminum Cast Iron Stainless Steel or Polypropylene Pump Body

Compare aluminum, cast iron, stainless steel and non metallic bodies by fluid, duty and weight, not by habit.

Answers

Pump Selection And Sizing FAQ

What information do I need to send for sizing?

Send the required flow in GPM or LPM, the discharge head in meters or psi, the fluid type, and the available air pressure in bar or psi. Include solids size if applicable.

Why is port size not based on the pipe thread?

The pipe thread determines how the spool connects, not the flow capacity. A 1 inch pipe can carry less flow than a 1 inch pump. The pump's port size is chosen for flow and solids handling, not the pipe.

Can a smaller pump handle the same flow as a larger one?

Yes, if the duty is within the pump's performance range. A 2 inch pump may not be needed for 100 GPM if the discharge head is low. We check the performance curve to confirm.

What if my air pressure is lower than 8 bar?

Lower air pressure reduces flow and maximum discharge head. We select a pump that performs within your actual air supply, which may mean choosing a different size than expected.

Do I need to change the repair kit when I change the pump?

Yes. Each pump model has a specific repair kit. When you get a new model code, we quote the matching air section and fluid section kits at the same time.

Send Us Your Duty

Provide your required flow, discharge head, fluid type, and air pressure. We will return the correct model code, port size, materials, and a price.

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