Front view of a gray industrial double diaphragm pump with flanged connections and a central air valve.

Grey industrial diaphragm pump with flanged ports and black center section on white background

Grey industrial air-operated double diaphragm pump on a white background

DP3X Series

1-1/2 Inch Non Metallic Air Operated Double Diaphragm Pump

The DP31 is the 1-1/2 inch non metallic pump in the DP3X series, and it is the model plants choose when handling aggressive fluids that attack metal. It moves up to 100 GPM, which is 378.5 LPM, at 120 psi or 8.3 bar, passes suspended solids to 6.4 mm and lifts 4.27 m dry. The polypropylene and PVDF body resists acids, alkalis, solvents and corrosive liquids, and the 28.1 kg weight keeps it portable. The stall free air motor ensures it starts under load every time, and the self-lubricating system means no oiler is needed on the air line.

Maximum flow rate	100GPM(378.5LPM)
Maximum operating pressure	120psi(8.3bar)
Suspended solids max diameter	1/4"(6.4mm)
Fluid inlet	1-1/2" ANSI/DIN Flange
Fluid outlet	1-1/2" ANSI/DIN Flange

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Electroplating And Surface Finishing Chemical Processing Water And Wastewater Treatment

Key Benefits

What The 1-1/2 Inch Non Metallic Build Buys You

Chemical resistance, weight and flow sit differently on this model than on the metallic version of the same hydraulic end.

Resists Acids, Alkalis And Solvents

The polypropylene and PVDF body handles aggressive fluids that would corrode aluminum, stainless steel or cast iron. This makes it the only choice for strong acids, caustics and many organic solvents.

378.5 LPM From Air Alone

All the pump needs is a 3/8 inch air line. No motor, no starter, no VFD, no earthing and no electrical area classification paperwork.

It Will Not Stall At The End Of A Stroke

A pilot air valve gives the major air valve a positive, fast shift signal. The pump trips over cleanly instead of sitting at mid stroke waiting for someone to tap the air end.

No Oiler On The Air Line

The air distribution system is self lubricating and lube free, so there is no oil mist in the exhaust and nothing to top up on a maintenance round.

Anti Icing By Design

A built in vacuum chamber lowers discharge air pressure, which cuts both the temperature drop that causes icing and the exhaust noise. The published sound level is 77.7 dB(A) at 70 psi and 60 cycles per minute.

It Fits Where Your Old Pump Sits

Installation dimensions and footprint are compatible with the major AODD brands, so the base, the pipe spools and the air line usually stay exactly as they are.

Who It Is For

Who Buys This Pump

The 1-1/2 inch non metallic model is the choice when the fluid attacks metal and the plant needs flow, portability and chemical resistance.

Chemical plants transferring acids, alkalis, solvents and electroplate liquids between tanks and process lines
Pharmaceutical and biotech labs handling shear sensitive formulations and reagents that degrade on contact with metal
Electronics manufacturers moving etchants, photoresist developers and cleaning agents through production lines
Food and beverage plants dosing condiments and additives where metal contamination is a risk
Waste water treatment plants handling corrosive sludge and chemical dosing streams
Contractors and maintenance teams who need one portable pump that handles aggressive fluids without corrosion

Problems It Solves

Problems This Pump Is Bought To Fix

Almost every enquiry for this model starts with a pump that failed at one of these five things.

A metallic pump corrodes in acid or alkali, while this pump resists the fluid and lasts longer
A centrifugal pump loses prime as soon as the tank runs down, while this pump self primes and can be run dry without damage
Line blockages deadhead the pump, and an AODD simply stops against the closed valve and starts again when the valve opens
Electric pumps bring an area classification argument to a solvent store, and air drive avoids that argument entirely
A 1-1/2 inch aluminum pump at 51.5 lbs cannot be lifted onto a trolley by two people, and 28.1 kg can

Application Scenarios

Where It Ends Up In A Plant

01

Chemical Transfer And Dosing

Self priming with 4.27 m of dry suction lift, so it draws from a tank or drum without a foot valve and can be used for precise dosing into a reactor.

02

Waste Water Chemical Feed

The pump can be dead headed as the line pressure builds, then restart when the valve opens, which suits chemical dosing into a clarifier.

03

Tanker And Drum Unloading

Self priming with 4.27 m of dry suction lift, so it empties a road tanker or a drum bank from ground level without a foot valve.

04

Pharmaceutical Formulation

The pump handles shear sensitive materials without degradation, and the non metallic body prevents metal contamination in the batch.

Technical Features

How The Air End Is Built

The hydraulic end of an AODD pump is simple. The air end is where pumps differ, and where Nuodean holds its patents.

Major Air Valve Plus Pilot Air Valve
The pilot valve is shifted mechanically by the actuator pin and pneumatically by the compressed air, then it shifts the major valve. That two stage signal is what makes the changeover positive and fast.
Dual Ceramic Dynamic Seals
Both the major air valve and the pilot air valve run ceramic dynamic seals. They resist wear, tolerate a dirty air supply and keep discharge contamination down over a long life.
Self Lubricating Lube Free Air System
No lubricator is fitted to the air inlet and none is needed, which removes both a maintenance task and the oil mist that a lubricated pump puts into the room.
Anti Icing Vacuum Chamber
The built in vacuum chamber reduces discharge air pressure, which lowers the expansion cooling that ices an air motor and drops the exhaust noise at the same time.
Interchangeable Installation Envelope
Port positions, foot spacing and overall envelope follow the major brands, so this pump can be dropped into an existing installation.
Selectable Wetted Materials
Center body, fluid caps and manifold, seat, ball check, diaphragm, connection thread and hardware are each chosen in the model code rather than fixed at the factory.

Specifications

Published Performance

Transcribed from the Nuodean data sheet published for this pump.

Maximum flow rate	100GPM(378.5LPM)
Maximum operating pressure	120psi(8.3bar)
Suspended solids max diameter	1/4"(6.4mm)
Fluid inlet	1-1/2" ANSI/DIN Flange
Fluid outlet	1-1/2" ANSI/DIN Flange
Air inlet	3/8"BSPT(3/8"NPT Available On Request)
Maximum dry suction lift	14feet(4.27m)
Sound level	77.7db(A)
Weight	62 lbs(28.1kg)
Model series code	DP31

Materials

Material Options

Set in the model code. Ask us if you need a combination the code allows but the sheet does not show.

Wetted body material	Non-metallic (polypropylene / pvdf)
Diaphragm options	Neoprene, Nitrile, Viton, E.P.R., Composite PTFE, HytreI, PTFE / Santoprene, Santoprene
Ball check options	Neoprane, Nitrile, Viton, PTFE, E.P.R., Polyurethane, HytreI, Santoprene
Seat options	316 Stainless Steel, Polypropylene, PVDF (Kynar), Hard 440 Stainless Steel
Housing options	Aluminum, Cast Iron, Grey Polypropylene Flange (3-piece manifold), Colorless Polypropylene Flange (3-piece manifold), PVDC (Kynar) Flange (3-piece manifold)

Performance figures are transcribed from the Nuodean data sheet for this pump. Flow is measured at the pump discharge with water at ambient temperature; your duty point depends on air supply pressure, suction conditions, fluid viscosity and discharge head. Ask our engineers to confirm the duty point before you order.

Quality Control

Before It Is Crated

Every pump is run on air before it leaves, so the shift behaviour is checked rather than assumed
Sound level is published for the model at 70 psi and 60 cycles per minute so you can hold us to it
Ball, seat and diaphragm materials are checked against the ordered model code at assembly
The pump ships with the data sheet and both the fluid section and air section part lists

Customization

What You Can Change

Center body in polypropylene or PVDF
Fluid caps and manifold in polypropylene or PVDF
Seat in 316 stainless steel, polypropylene, PVDF (Kynar) or hard 440 stainless steel
Ball check in neoprene, nitrile, Viton, PTFE, EPDM, polyurethane, Hytrel or Santoprene
Diaphragm in neoprene, nitrile, Viton, EPDM, composite PTFE, Hytrel, PTFE / Santoprene or Santoprene
1-1/2 inch ANSI/DIN flange fluid connections, stainless steel or carbon steel hardware
3/8 inch NPT air inlet in place of the standard 3/8 inch BSPT, on request

Comparison

Against The Alternatives

Where this pump wins and where you should be buying something else.

Versus the 1-1/2 inch aluminum version	Same 378.5 LPM and same 8.3 bar, but 28.1 kg against 51.5 kg and full chemical resistance. Choose aluminum when the fluid is non-corrosive and weight matters.
Versus the 1-1/2 inch stainless steel version	Same 378.5 LPM and same 8.3 bar, but 28.1 kg against 84.5 kg and full chemical resistance. Choose stainless when the fluid is non-corrosive and the duty is high pressure.
Versus the 1-1/2 inch cast iron version	Cast iron at 79.5 kg is the choice for abrasive slurry duty where wall wear matters. non metallic is the choice where chemical resistance and portability matter.
Versus the 1 inch non metallic version	The 1 inch reaches 177.9 LPM and is lighter at 9.2 kg, but the 1-1/2 inch gives 378.5 LPM and is the only choice when flow is the main requirement.
Versus the 1 inch aluminum version	The 1 inch aluminum gives 133 LPM and is lighter at 8.6 kg, but the 1-1/2 inch gives 378.5 LPM and is the only choice when flow is the main requirement.
Versus the 1-1/2 inch metallic pumps	The metallic versions are stronger and can handle abrasives better. The non metallic version is the only choice when the fluid attacks metal.

Use Guide

Getting The Best Out Of It

Five things that decide whether this pump does 378.5 LPM or half of it.

Give It Real Air
Flow follows air. Use the full 3/8 inch inlet, keep the hose short and confirm the compressor can hold pressure at the flow the pump asks for.
Do Not Throttle The Suction
Throttle the discharge or the air, never the suction. Starving the suction is what causes cavitation, hard running and short diaphragm life.
Match The Elastomer To The Fluid
Diaphragm and ball material is chosen in the model code. Get the chemistry right and the pump lasts. Get it wrong and nothing else you do will save it.
Keep Suction Lift Honest
The published 4.27 m is a dry lift figure on the data sheet. Priming a flooded suction is always easier, so put the pump below the tank where the layout allows.
Stock The Two Repair Kits
One air section kit, DP31-Air50, and one fluid section kit, DP31-Flu50, coded for your diaphragm and ball material. Between them they cover almost every wear part.

Documents

Documents For This Pump

Straight from Nuodean's own literature: fluid and air section drawings, product data sheets, series catalogues.

PDF 1.5 INCH DP3X Non metallic AODD PUMPS DATA SHEET Product Data Sheets PDF 1.2 MB Download PDF DP3X AODD PUMPS Catalogue Series Catalogues PDF 18.1 MB Download PDF Fluid Section of 2 inch DP11 Non metallic Pump Fluid And Air Section Drawings PDF 373 KB Download PDF Air Section of 1.5 inch DP11 Metallic and Non metallic Pump 1 Fluid And Air Section Drawings PDF 174 KB Download

Need a 2D or 3D CAD model of this pump? CAD on request via WhatsApp.

Answers

1-1/2 Inch Non Metallic Air Operated Double Diaphragm Pump FAQ

What flow will this pump actually give me?

100 GPM, which is 378.5 LPM, is the maximum with a free discharge and full air supply. Real duty points are lower. Send us the discharge head and the air pressure you can hold and we will tell you where on the curve you land.

Can it run dry?

Yes. An air operated double diaphragm pump can be run dry and can be dead headed against a closed valve without damage. That is the main reason plants choose one over a centrifugal pump.

What is the largest solid it will pass?

1/4 inch, which is 6.4 mm, on the suspended solids figure from the data sheet. If your fluid carries bigger solids, look at the 3 inch models at 9.5 mm or the heavy duty flap valve pump at 50 mm.

Will it replace another brand of 1-1/2 inch AODD pump?

Usually yes. The DP3X pumps are built so that installation dimensions and footprint are compatible with other brands. Send a photo of the nameplate and the pipework and we will confirm before you buy.

Which diaphragm should I order?

PTFE with a Santoprene backing for aggressive solvents and acids, Santoprene for general duty and long flex life, Viton for hot oils and aromatics, nitrile for petroleum products. Tell us the fluid and the temperature and we will put the right code on the quotation.

How loud is it?

77.7 dB(A) at 70 psi and 60 cycles per minute, as printed on the data sheet. Slower cycling is quieter, and a piped exhaust takes more off.

What connections does it come with?

Fluid inlet and outlet are 1-1/2 inch ANSI/DIN flange. The air inlet is 3/8 inch BSPT female, with 3/8 inch NPT available on request.