Diaphragm Pump

Every diaphragm pump on this page was picked for one reason: it keeps moving fluid when other pumps give up. We run our warehouse out of Perth, and most weeks we are shipping a diaphragm pump to a mine site in the Pilbara, a spray contractor in the Wheatbelt, a treatment plant in Kwinana, or a dairy in the South West. That is the kind of work a diaphragm pump is built for. It shifts ferric chloride, sodium hypochlorite, bore water loaded with grit, sludge, waste oil and thick slurry without chewing itself apart the way a centrifugal pump does. If you have replaced a mechanical seal three times this year, a diaphragm pump is almost certainly the fix. Below you will find electronically controlled dosing units from ITC and heavy duty mechanical models from ASM, with live pricing, real specs and stock ready to ship Australia wide.

What a Diaphragm Pump Actually Does

A diaphragm pump is a positive displacement pump. A flexible membrane flexes back and forth inside a chamber, and two one way check valves make sure fluid only travels one direction. On the pull stroke it draws liquid in. On the push stroke it sends that liquid out. There is no impeller spinning against your fluid and no mechanical seal to fail, because the diaphragm keeps the wet end fully isolated from the drive.

That single design choice is why a diaphragm pump can do things other pumps cannot. A diaphragm pump self primes, so you can mount it above the liquid. It runs dry without damage, which matters when a tank empties overnight. It handles solids in suspension. It delivers close to the same flow whether you are pushing into 100 kPa or 600 kPa. And it gives you dosing accuracy that a centrifugal pump will never match, which is exactly why every water treatment plant in WA runs one.

Diaphragm Pump Types: Mechanical, Air Operated and Electronic Dosing

There are three families, and picking the wrong one is the most common mistake we see. A mechanical diaphragm pump uses an electric motor and a cam or eccentric to drive the membrane. Our ASM range works this way, from the 1 inch DS25 at 1.38 m³/h up to the 3 inch DS76 at 14 m³/h, in 240V single phase and 415V three phase. This is the workhorse choice for transfer, sump emptying, spray rigs and general site duty.

An air operated double diaphragm pump, usually shortened to AODD, uses compressed air instead of electricity. Brands like Wilden, ARO and Graco dominate that space. An AODD diaphragm pump suits flameproof zones and underground mining where you already have reticulated air, but it burns roughly 2 to 3 CFM per litre per minute of flow, so your compressor bill is the real cost.

An electronic dosing diaphragm pump is the precision end. Our ITC DOSTEC AC range uses step motor control to inject anywhere from 6.5 L/hr up to 1254 L/hr at pressures to 1500 kPa, with 4 to 20 mA and pulse input so it talks to your PLC. The EFR dual head models push past 2500 L/hr. If you are chlorinating a scheme supply, dosing a cooling tower or feeding coagulant, this is the group you want.

How to Choose the Right Diaphragm Pump

After a decade of taking these calls, we ask four questions in the same order every time, and it saves people a lot of money.

Match the Diaphragm Pump to the Fluid First

The fastest way to destroy a diaphragm pump is to pick the wrong elastomer. Buna N is fine for water, oils and diesel but hates strong oxidisers. Viton handles acids and solvents. EPDM is the right call for sodium hypochlorite and caustic. PTFE is close to universally compatible and is what we recommend when nobody can tell us exactly what is in the tank. Body material matters just as much. Polypropylene for aggressive chemistry, SG iron or aluminium for abrasive transfer duty. Tell us the fluid, the concentration and the temperature and we will match the wetted parts properly.

Size on Duty Point, Not Peak Numbers

Catalogue flow figures are measured at open discharge. Your real duty point is flow at your actual head, and once you add static lift, pipe friction and a filter, a lot of that headline number disappears. Work out the total dynamic head first, then choose a diaphragm pump that sits comfortably in the middle of its curve. A pump running flat out at maximum pressure all day will burn diaphragms in months. One running mid curve will last years. If you are unsure, send us the layout and we will do the calculation.

Diaphragm Pump Port Size, Power and Duty Cycle

Port size drives diaphragm pump flow more than anything else, so match it to the pipework you already have rather than necking down with reducers. Check what power you actually have on site, because 415V three phase is common on farms and industrial blocks but plenty of remote sheds only have single phase. And be honest about run time. A diaphragm pump running eight hours a day needs a heavier build than one that runs twenty minutes.

Plan for Diaphragm Pump Spare Parts Before You Buy

Diaphragm pump membranes and valve balls are wear items. Two to five million cycles is normal service life, which is a season or two of hard work. The mistake is buying an orphan brand and then waiting six weeks for a kit from overseas. We hold ASM spare parts in Perth for exactly this reason, and we can send a repair kit the same day you call.

Where a Diaphragm Pump Earns Its Keep in WA

In mining and dewatering, a diaphragm pump handles abrasive slurry, pit water and tailings without the seal failures that plague centrifugal units underground. Because it runs dry safely, it can sit in a sump that only fills sometimes without anyone babysitting it. Plenty of sites pair one with a Tsurumi submersible for staged dewatering.

In agriculture across the Wheatbelt and Great Southern, a diaphragm pump drives boom sprayers, moves liquid fertiliser and NIS, transfers herbicide from shuttles, and handles trace element injection. Growers like it because the pressure holds steady as nozzles open and close. Many of our farm customers run a diaphragm pump alongside a submersible bore pump and a pressure tank so their spray fill and their house supply are on separate circuits.

In water treatment, from Kwinana to Karratha, a dosing diaphragm pump injects chlorine, soda ash, antiscalant and pH correction with the repeatability an operator needs to pass compliance. It pairs naturally with Filtaworx screen filters and stainless BSP fittings for a clean, serviceable skid.

In workshops, food processing and general industry, a diaphragm pump moves waste oil, coolant, detergent, adhesives and viscous product that would cavitate anything else. It is also the safest choice for decanting drums and IBCs, since it will not run itself dry into failure if the drum empties.

Why Buy Your Diaphragm Pump From Pumptastic

Here is the honest gap in this market. Most Australian pump suppliers will not show you a price. You land on their diaphragm pump page, read three paragraphs of marketing, then hit an enquiry form and wait two days for a quote. We publish pricing on every diaphragm pump we sell, list the flow in L/hr or m³/h, the pressure in kPa, the port size in NB and BSPF, and the motor rating, so you can compare properly before you spend a cent.

We are also a real pump shop, not a drop shipper. You can call our team on (08) 6384 5884 between 9am and 5pm WST and talk to someone who has actually commissioned this gear. That matters most for a diaphragm pump, because selection is genuinely technical and a wrong elastomer choice is an expensive lesson. Orders over $100 ship free Australia wide through Australia Post, and being WA based means Perth metro, Bunbury, Geraldton, Kalgoorlie and Albany all get their pump faster than they would from an east coast warehouse.

If your application needs something else, we stock the alternatives too, including Grundfos pressure pumps, Davey pumps, Ebara centrifugal pumps, sump pumps and pump controllers. We would rather point you at the right pump than sell you the wrong diaphragm pump.

Browse the range below, or call us and we will spec it for you in about ten minutes. If you know you want a mechanical unit, go straight to our ASM diaphragm pump range. If you need metering and control, start with the ITC dosing pump range.

Frequently Asked Questions

How does a diaphragm pump work?

A flexible membrane flexes in and out of a chamber while two check valves control direction. Suction pulls fluid in, discharge pushes it out. Because the membrane separates the fluid from the drive, there is no seal to leak.

What is the difference between a diaphragm pump and a centrifugal pump?

A centrifugal pump spins an impeller and needs to stay flooded. A diaphragm pump displaces a fixed volume each stroke, self primes, survives running dry, and holds flow steady as pressure rises. Centrifugal wins on high flow clean water. Diaphragm wins on chemicals, solids and variable pressure.

Can a diaphragm pump run dry?

Yes, and that is one of its best features. Short dry running does no harm. Extended dry running still generates heat, so fit a level switch on unattended installations.

What is an AODD diaphragm pump?

Air operated double diaphragm. It uses compressed air rather than an electric motor, which makes it a good fit for hazardous and flameproof areas. The trade off is high air consumption.

What fluids can a diaphragm pump handle?

Acids, caustics, chlorine, fuels, oils, adhesives, slurries, sludge and food product, provided the wetted materials match. Confirm the elastomer and body material against your chemical before ordering.

How long does a diaphragm pump diaphragm last?

Typically two to five million cycles. Running mid curve rather than at maximum pressure roughly doubles service life. Keep a spare kit on the shelf.

Do you deliver to regional WA and the rest of Australia?

Yes. We ship Australia wide, and orders over $100 are free. Regional WA, including the Pilbara, Goldfields and South West, is routine for us.

Can a diaphragm pump be used for potable water?

Yes, where the wetted materials are rated for drinking water contact. Our chlorine dosing models are widely used on rural scheme and tank supplies. Ask us to confirm the specific model.

Should I choose a single phase or three phase diaphragm pump?

Our ASM range comes in both 240V single phase and 415V three phase. Three phase is more efficient for continuous duty. Single phase suits sheds and remote sites without three phase available.

What if I am not sure which diaphragm pump I need?

Call (08) 6384 5884 or use our contact page with your fluid, flow, pressure and pipe size. We will spec it the same day. There is no charge for advice.