Air Operated Double Diaphragm Pumps
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ARO 1/2" Air Operated Double Diaphragm (AODD) Pumps
An air operated double diaphragm pump moves liquid with nothing but compressed air. Air pressure flexes two diaphragms in turn, one chamber drawing fluid in while the other pushes it out, and check balls keep the flow going one way. There is no electric motor at the pump, no mechanical shaft seal, and when the outlet closes the pump stalls and holds line pressure, then restarts on demand, which makes it a simple, dependable air powered transfer pump. This page carries 20 ARO 1/2" air operated diaphragm pumps in polypropylene, groundable acetal and aluminum, with flow up to 14.4 GPM and discharge pressure up to 100 psi. ARO is an Ingersoll Rand brand.
Two Pump Families: 66605X and PD05
Every pump here has 1/2" fluid ports, a 1/4" air inlet and a 1:1 ratio, which means the discharge pressure follows the air pressure you supply, up to 100 psi. They come from two families of ARO air diaphragm pumps, and the model number tells you which one you are looking at.
66605X
13 models, polypropylene or groundable acetal
Up to 13 GPM with check balls, 10 GPM with duckbill valves. Air inlet 20 to 100 psi.
Service kits: 637141 air section, 637140-XX fluid section
PD05P ... -B
6 models, polypropylene
Up to 14.4 GPM, the highest flow on this page. Air inlet 10 to 100 psi.
Service kits: 637428 air section, 637427-XX fluid section
PD05R ... -B
1 model, aluminum
Up to 12 GPM in a metallic body. Air inlet 10 to 100 psi.
Service kits: 637428 air section, 637427-XX fluid section
Reading a 66605X model number
The sixth character gives the body: 3 and J are polypropylene, 6 and H are groundable acetal. Models with 3 or 6 have a three-piece fluid cap and manifold, J and H a one-piece design. The three characters after the dash are the seat, ball and diaphragm materials, so the 66605J-3EB has polypropylene seats with Santoprene balls and diaphragms.
Choose the Body Material
The body and manifolds are wetted parts too, so they need to suit the fluid as much as the diaphragms do.
- Polypropylene The body on 17 of the 20 pumps, across both families. A non-metallic, corrosion-resistant body for general chemical transfer, and the usual starting point for a chemical resistant diaphragm pump when paired with PTFE diaphragms and balls. Rated 35°F to 175°F.
- Groundable acetal 666056-2A4, 66605H-644. The acetal is conductive, so the pump can be connected to a suitable ground where static dissipation matters. Rated 10°F to 180°F. The 666056-2A4 also has stainless steel seats and balls.
- Aluminum PD05R-AAS-PGG-B, a metallic pump with nitrile balls and diaphragms, a combination commonly chosen for oils and petroleum-based fluids.
Match the Diaphragms and Balls to Your Fluid
The body sets the family, but the diaphragm and ball materials decide what the pump can handle day to day. Each material has its own temperature range, and a pump is limited by the narrowest range among the materials it is built from.
| Elastomer | Temperature range | Commonly selected for | Pumps on this page |
|---|---|---|---|
Santoprene |
-40°F to 225°F |
General industrial service |
66605J-3EB, 666053-3EB, PD05P-APS-PAA-B, PD05P-ARS-PAA-B, and 66605J-34B with PTFE balls |
PTFE (PTFE-faced diaphragms) |
40°F to 225°F |
Broad chemical resistance |
66605J-344, 666053-344, 66605H-644, 666056-2A4, PD05P-APS-PTT-B, PD05P-ARS-PTT-B |
Nitrile |
10°F to 180°F |
Oils and petroleum-based fluids |
666053-322, 66605J-322, PD05P-ARS-PGG-B, PD05R-AAS-PGG-B, 666053-0D2 |
Polyurethane |
10°F to 150°F |
Wear resistance |
|
Neoprene |
0°F to 200°F |
General industrial service |
Duckbill valves for fibrous fluids
The 666053-0D2 replaces the check balls with nitrile duckbill valves. It is rated at 10 GPM rather than 13, and ARO lists its solids capability as fibers rather than a particle size, which makes it the option on this page for stringy or fibrous material.
Check compatibility before you order
Confirm the complete pump, including body, seats, balls and diaphragms, against the fluid's full composition, concentration, temperature and solids content, using the ARO chemical compatibility guide.
Air Supply, Speed Control and Installation
An air powered double diaphragm pump is only as steady as the air feeding it. ARO's operator manuals for these pumps set out a few simple requirements:
- Filter the air supply to remove particles larger than 50 microns
- No lubricator is needed. If the air is lubricated anyway, the oil must be compatible with the O-rings and seals in the air motor
- Allow roughly 1 CFM of air for every gallon pumped as a planning figure
- Set pressure at a regulator and fine-tune speed with a needle valve in the air line
- Mount the pump vertically so the check balls seat by gravity and the pump can prime itself
- Use a suction line at least 1/2" that will not collapse, and add a check valve at the air inlet when the pump runs with a flooded inlet
One kit for the air connection
The 66073-1 air line connection kit, with hose, filter regulator and fittings, is listed as an accessory for the 66605X, PD05P and PD05R pumps. For a separate unit, a 5 micron piggyback filter regulator meets the 50 micron requirement with room to spare.
Service Kits and Spare Parts
Each pump has two service kits: an air section kit for the air motor, and a fluid section kit with the balls, diaphragms and O-rings for its material combination. For 66605X pumps, the fluid kit number ends with the last two characters of the model, so the 66605J-3EB takes 637140-EB and the 66605J-344 takes 637140-44. PD05 pumps ending in -B use the 637428 air section kit and 637427-XX fluid kits.
The 637141 air section kit, the 637140-EB and 637140-44 fluid kits, the 66073-1 air line kit and the 76763 wall mount bracket are all on the pump parts and kits page.
Frequently Asked Questions
What is an AODD pump?
An air operated double diaphragm (AODD) pump uses compressed air to flex two diaphragms in turn. As one chamber draws fluid in, the other pushes it out, and check balls keep the fluid moving in one direction. There is no electric motor at the pump, and when the discharge is closed the pump stalls and holds line pressure, then starts again as soon as the line opens. The ARO 1/2" AODD pumps on this page deliver up to 14.4 GPM at up to 100 psi.
What is the difference between ARO 66605X and PD05 diaphragm pumps?
Both are 1/2" AODD pumps with a 1:1 ratio and a 100 psi maximum. The 66605X family comes in polypropylene or groundable acetal, delivers up to 13 GPM with ball checks and runs on 20 to 100 psi air. The PD05P models ending in -B are polypropylene, deliver up to 14.4 GPM and run on 10 to 100 psi air, and the PD05R-AAS-PGG-B is the aluminum version at up to 12 GPM. The two families take different service kits, so always match kits to the full model number.
Which diaphragm and ball material should I choose?
Start from the fluid. On this page, Santoprene is the general-service option, PTFE-faced diaphragms with PTFE balls cover the broadest chemical resistance, nitrile is commonly chosen for oils and petroleum-based fluids, and polyurethane is chosen for wear resistance. Check temperature too: a pump is limited by the narrowest range among its materials, for example 35°F to 175°F for a polypropylene body. Confirm the full configuration in the ARO chemical compatibility guide.
What air supply does an ARO 1/2" diaphragm pump need?
Compressed air at up to 100 psi through the pump's 1/4" air inlet. ARO's manuals call for a filter that removes particles larger than 50 microns, and no lubricator is required. As a planning figure, allow roughly 1 CFM of air for every gallon pumped. A filter regulator, like the one in the 66073-1 air line connection kit, filters and sets the air pressure in one unit.
How do I adjust the flow of an air operated diaphragm pump?
Flow and pressure both follow the air supply. Lowering the air pressure at the regulator lowers the pressure the pump can build, and throttling the air with a needle valve slows the cycle rate and the flow. ARO lists the 1/4" needle valves 104104-N02 and 104104-NS2 for its 1/4" to 1" diaphragm pumps. Output also depends on the suction side, so keep the inlet line at least 1/2" and use hose that will not collapse.
Which repair kit fits my ARO diaphragm pump?
Use the full model number from the nameplate. 66605X pumps take the 637141 air section kit and a 637140 fluid section kit whose suffix matches the last two characters of the model, so the 666053-3EB takes 637140-EB. PD05 pumps ending in -B take the 637428 air section kit and a 637427 fluid kit matched the same way, so the PD05P-ARS-PAA-B takes 637427-AA. The 637141, 637140-EB and 637140-44 kits are stocked on our Parts & Kits page.
Build the Complete Pump Station
Choose the pump by fluid first: body material, then diaphragms and balls, then temperature. Then complete the installation with clean, regulated air, a way to set the speed, and the right service kits on the shelf.
Order your pump above, and add a piggyback filter regulator or a separate filter and regulator, needle and flow control valves, and repair kits. For industrial diaphragm pumps selected by application, see the industry pages for car wash, food & beverage, cosmetic & pharmaceutical, general manufacturing and packaging.
Not sure which pump suits your fluid?
Talk to ARO about chemical compatibility, sizing or service kits. Monday to Friday, 08:00 am to 5:00 pm CST.