--- title: "Double Diaphragm Pump Selection Guide: Flow, Pressure & Material" date: 2026-08-06T02:51:09Z modified: 2026-08-25T03:48:37Z permalink: "https://www.defucc.com/blog/buying-guide/double-diaphragm-pump-selection/" type: post status: publish excerpt: "" wpid: 2823 categories: - buying guide featured_image: "https://www.defucc.com/wp-content/uploads/2026/08/image-77.webp" featured_image_alt: Double Diaphragm Pump timestamp: 2026-08-25T03:48:37Z tags: - buying guide --- ## **Quick Answer:** Select a double diaphragm pump by matching flow, discharge pressure, air supply, fluid properties, solids size and wetted materials to the process. DEFUCC manufactures AODD pumps in metal and plastic material options for chemical, wastewater and other industrial fluid-transfer applications. For procurement, material compatibility is often as important as pump capacity. A correctly sized pump can still fail early if its body, diaphragm or valve materials do not suit the liquid. ## **Which Specifications Matter Most When Buying a Double Diaphragm Pump?** A buyer should compare the operating requirements before comparing pump sizes. The core purchasing parameters are: | **Parameter** | **Why It Matters** | | --- | --- | | Required flow | Determines basic pump capacity | | Discharge pressure | Determines whether the pump can overcome system resistance | | Air supply | Affects achievable flow and pressure | | Fluid chemistry | Determines body and diaphragm materials | | Viscosity | Can reduce practical flow | | Solids size | Must stay within the pump’s passage limit | | Suction lift | Affects installation suitability | | Hazardous environment | Influences material and air-driven configuration | These parameters are more useful for procurement than repeating how an [AODD pump](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/post/aodd-vs-eodd-choose-right-diaphragm-pump.md) works, especially when the working principle is already covered elsewhere. ## **How Much Flow Does an AODD Pump Need?** Choose pump capacity from the required process flow, then check whether that flow remains achievable at the expected air pressure and discharge pressure. The maximum flow printed in a catalog normally represents a favorable operating condition. Actual flow can decrease as discharge pressure, fluid viscosity or suction difficulty increases. ### **Should You Size the Pump at Its Maximum Flow?** Usually, no. Running a pneumatic diaphragm pump continuously at its extreme published capacity may leave little margin for changes in the process. A better procurement approach is to establish: **·** Normal required flow **·** Maximum required flow **·** Operating pressure **·** Fluid viscosity **·** Suction conditions **·** Expected duty cycle Then review the manufacturer’s performance data for that combination. An [AOK air diaphragm pump](https://www.defucc.com/product/aok-series-air-diaphragm-pump/) covers several inlet and outlet sizes. Published models range up to 63.6 m³/h, with maximum head and solids capacity varying by size. ![Double Diaphragm Pump](https://www.defucc.com/wp-content/uploads/2026/08/image-78-1200x800.webp) ## **How Much Pressure Does a Double Diaphragm Pump Need?** Required discharge pressure must be high enough to overcome elevation, pipe resistance and any downstream process pressure. For an air-operated pump, the available compressed-air pressure also limits performance. ### **What Should Buyers Check About the Air Supply?** Confirm: 1\. Available air pressure 2\. Available air volume 3\. Air-line diameter 4\. Air quality 5\. Pressure stability 6\. Expected simultaneous air demand from other equipment A plant may have adequate nominal pressure at the compressor but insufficient pressure at the pump after losses through long or undersized air lines. ### **Can More Air Pressure Always Increase Performance?** No. Every pump has a maximum permitted air-supply pressure. Increasing air pressure beyond the pump’s rated limit can damage components and create unsafe operating conditions. The selected model should achieve the required flow and discharge pressure within its approved operating range. ## **How Do You Match Pump Material to the Fluid?** Match every wetted component to the chemical, concentration, temperature and solids present in the liquid. This is one of the most important steps when specifying a double diaphragm pump. Common pump-body options shown across DEFUCC’s air diaphragm range include: **·** Cast iron **·** Aluminum **·** Polypropylene (PP) **·** Polyvinylidene fluoride (PVDF) **·** SS304 stainless steel **·** SS316 stainless steel The correct choice depends on what the fluid will contact. ### **When Are Plastic Pump Bodies Useful?** Plastic materials can be useful where chemical resistance is more important than mechanical strength. PP and PVDF may suit selected corrosive liquids, but compatibility depends on the exact chemical concentration and temperature. Do not choose “plastic” as a general chemical solution without checking a compatibility chart. ### **When Are Metal Pump Bodies Appropriate?** Metal bodies can suit many industrial fluids where impact resistance or mechanical durability matters. Aluminum, cast iron and stainless steels have different chemical limitations. SS316 can provide better corrosion resistance than some other metal options, but it is not universally compatible with every chemical. The fluid specification should determine the material rather than the assumption that one material is always superior. ## **Which Diaphragm Material Should You Choose?** Choose [diaphragm material](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/post/diaphragm-pump-materials-chemical-applications.md) from chemical compatibility, temperature, flexibility and expected wear. DEFUCC lists diaphragm choices including PTFE, Santoprene, Buna-N and Viton across its air diaphragm product information. ### **How Do Common Diaphragm Materials Differ?** Material compatibility varies by application: ****·**** **PTFE:** Commonly considered where broad chemical resistance is required. **·** **Buna-N:** Often considered for oils and hydrocarbon-related liquids. ****·**** **Viton:** Used in selected chemical and higher-temperature applications. **·** **Santoprene:** Can provide flexibility and resistance for various general industrial fluids. These are general selection directions, not universal compatibility rules. Verify the exact fluid, concentration and temperature before ordering. ## **How Do Solids and Viscosity Affect Pump Selection?** Solids and viscosity can significantly change the pump size required for an application. ### **What Solids Size Can an AODD Pump Handle?** Check the maximum particle size for the exact model rather than assuming all [diaphragm pumps](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/post/diaphragm-pumps-pros-and-cons.md) have the same passage. The [AOE air diaphragm pump](https://www.defucc.com/product/aoe-air-diaphragm-pump/) lists maximum solids sizes up to 6.4 mm for plastic configurations and up to 9.5 mm for the 3-inch metal model. Large particles are not the only concern. Abrasive fine solids can also affect diaphragm, valve and seat life. AOK Series Air Diaphragm Pump AOK series air diaphragm pump has the characteristics of simple structure, easy use and stable operation, which is same as Graco Husky brand diaphragm pump which can be interchanged with same performance. [Explore Mine-Dewatering Pumps](https://www.defucc.com/product/aok-series-air-diaphragm-pump/) [ ![AOK Series Air Diaphragm Pump](https://defucc.b-cdn.net/wp-content/uploads/2025/04/AOK-New-Product-img-800x800.jpg) ](https://www.defucc.com/product/aok-series-air-diaphragm-pump/) ### **Why Does Viscosity Matter?** Higher viscosity increases resistance to flow. Paint, adhesive, sludge and concentrated chemicals may therefore produce less actual flow than water under the same nominal conditions. When requesting a pump, provide viscosity in centipoise (cP or cps) when available instead of simply describing the fluid as “thick.” ## **What Should You Check for Hazardous Environments?** For hazardous applications, evaluate both the pumped fluid and the surrounding operating area. Air-operated pumps do not require an electric motor at the pump itself. This can make them useful where minimizing electrical ignition sources is important. DEFUCC’s AOE product page specifically describes the air-driven configuration as suitable for transferring flammable fluids and lists hazardous-industry applications. However, using an air-operated pump does not automatically make an installation compliant with every hazardous-area standard. ### **What Else Must Be Verified?** Depending on the project, verify: **·** Grounding and static-control requirements **·** Conductivity of pump materials **·** Hose compatibility **·** Fluid flash point **·** Local hazardous-area classification **·** Compressed-air equipment **·** Exhaust-air routing The facility’s applicable safety requirements should control the final configuration. ## **How Can You Compare Two AODD Pump Quotations?** Compare quotations using the same operating conditions rather than looking only at inlet size. A procurement comparison can use the following format: | **Buyer Requirement** | **Supplier A** | **Supplier B** | | --- | --- | --- | | Required flow | | | | Discharge pressure | | | | Air pressure required | | | | Pump body material | | | | Diaphragm material | | | | Valve/seat material | | | | Maximum solids size | | | | Suction lift | | | | Fluid compatibility confirmed | | | | Spare diaphragm kit | | | This format makes technical differences visible before price becomes the deciding factor. ## **What Information Should You Send Before Ordering?** A complete RFQ should state the process requirements clearly. Include: **·** Liquid name **·** Chemical concentration **·** Required flow **·** Required discharge pressure **·** Temperature **·** Viscosity **·** Density **·** Maximum solids size **·** Solids concentration **·** Available compressed-air pressure **·** Suction lift **·** Required body material **·** Preferred diaphragm material **·** Hazardous-area requirements **·** Expected operating hours If material compatibility is uncertain, provide the full fluid composition instead of guessing at a pump material. ## **What Is the Best Way to Select a Double Diaphragm Pump?** Choose the pump only after confirming flow, pressure, air supply, solids, viscosity and material compatibility. These purchasing parameters determine whether the pump can meet the process without premature wear or chemical attack. DEFUCC can be evaluated using the same procurement checklist. Its AOK and AOE air diaphragm ranges include several body and diaphragm materials, multiple sizes and compressed-air configurations for chemical and industrial fluid transfer. [Get Free Quote](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/page/contact.md)