Qingdao Nuodean Pump Co Ltd — air operated double diaphragm pumps since the DP series
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Nuodean AODD pumps for water and wastewater treatment
Industry Application

AODD Pumps For Water And Wastewater Treatment Plants

Waste water, liquid waste, sludge, water seepage and filter press feed are named applications in our catalogues. These duties involve variable solids, changing batch chemistry, and long periods of dead heading as the press cake builds.

Talk To An Engineer See Recommended Pumps
Pain Points

What Goes Wrong In A Wastewater Transfer Duty

Three failure modes account for most of the pumps that fail early in wastewater service.

The Impeller Clogs Or The Seal Leaks

Centrifugal pumps with rotating parts are vulnerable to solids and grit. A diaphragm pump has no impeller and no shaft seal, so it handles solids and runs dry without damage.

The Pump Cannot Handle The Solids

Sludge and filter press feed contain particles that block close clearance pumps. The flap valve pump passes 50 mm solids, which is essential for feed to a press.

The Pump Dies When The Press Cake Builds

Dead heading is normal in press feed. A pump that cannot tolerate dead heading will overheat or fail its diaphragm. AODD pumps are designed for continuous dead heading.

What Buyers Need

What Wastewater Buyers Actually Specify

The specification usually comes down to six lines, and all six are settled in the model code before the pump is built.

  • Wetted materials that resist abrasion and corrosion from sludge and water seepage, which means cast iron for high pressure and non-metallic (polypropylene or PVDF) for chemical resistance
  • PTFE faced diaphragms for long life in abrasive and variable fluids, with Santoprene backing for flex fatigue resistance
  • No electric motor in the area, so the pump runs on plant air and avoids electrical hazards in wet zones
  • Dry running and dead heading tolerated as normal operation, not as an incident
  • Self priming with real dry lift so tanks and sumps can be emptied from ground level
  • Published drawings and part lists so a plant can hold the right spares before a shutdown
Drop In Replacement And RetrofitPump Selection And SizingAbrasive And High Solids Transfer
3D render of a stainless steel double diaphragm pump.
Typical Duties

Typical Duties On A Wastewater Site

01

Filter Press Feed

The flap valve pump passes 50 mm solids and handles the variable flow as the press cake builds. It dead heads safely at the end of each cycle.

02

Sludge Transfer From Sumps

Self priming from ground level with the pump above the sump, and dry running accepted when the sump empties.

03

Water Seepage And Liquid Waste

Transfer of variable batches with solids and grit, where the pump must survive dry running and dead heading.

04

System Flush And Clean Down

Flushing lines between batches, where the pump has to swallow air, then liquid, then air again.

How We Work

How We Get From Enquiry To Pump

Four steps. The first one is the only one that matters, and it is the one most enquiries skip.

  1. Name The Fluid Properly

    Sludge, water seepage or liquid waste. Include the solids size and whether the fluid is abrasive or corrosive. The flap valve pump is needed only if solids are 50 mm.

  2. Fix The Wetted Materials

    We set the body, seat, ball and diaphragm against the fluid. Cast iron for high pressure and abrasion, non-metallic (polypropylene or PVDF) for chemical resistance. Check the hardware and connection thread for corrosion.

  3. Set The Duty Point

    Flow at your discharge head with your available air pressure. That is what decides the port size, not the size of the pipe you already have.

  4. Agree The Spares Package

    One air section kit and one fluid section kit coded to your elastomer choice, so the first failure is a fifteen minute job rather than a three week wait.

Supply And Delivery

What Ships With The Pump

Related Guides

Guides For Wastewater Duty

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

Water And Wastewater Treatment Pump FAQ

Which pump should I use for filter press feed with large solids?

The heavy duty flap valve pump passes 50 mm solids and is designed for dead heading. It has no body, so it is not subject to corrosion from the feed. Use it when solids are larger than 25 mm.

Can the pump handle grit and abrasive sludge?

Cast iron bodies resist abrasion in high pressure service. The 3 inch cast iron pump has a flow of 897 LPM and a dry suction lift of 5.4 meters. It is suitable for high volume transfer.

What if the fluid is corrosive?

Non-metallic bodies made from polypropylene or PVDF resist corrosion from acidic or alkaline waste. The 2 inch non-metallic pump has a dry suction lift of 4.27 meters and is suitable for chemical resistance.

How do I know if the pump can run dry?

All AODD pumps are designed for dry running. The 3 inch cast iron pump has a dry suction lift of 5.4 meters, which means it can draw from ground level. The flap valve pump has a dry suction lift of 8.3 meters.

What if the pump is used in a wet or hazardous area?

The pump is air driven with no electric motor, so it does not create sparks. It is suitable for wet zones. We do not publish an ATEX certificate, so if your area requires one, tell us before ordering.

Send Us The Fluid And The Duty

Fluid type, solids size, flow and discharge head. We will come back with the wetted part list, the model code and a price.

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