An air operated double diaphragm (AODD) pump is a commonly used fluid transfer device that uses compressed air as its power source. Through the reciprocating motion of the diaphragm, it facilitates the intake and discharge of fluids. With its simple structure, easy maintenance, and versatility in transferring various media, it is widely used in industries such as chemicals, pharmaceuticals, and food processing. For many businesses and individual users, selecting the right air operated double diaphragm pump can be a challenging task. Different operating conditions require different specifications for the pump's materials, flow rate, head, inlet and outlet sizes, and more. Tool.com provides some key factors to help you choose the most suitable air operated double diaphragm pump.
Choose Based on the Diaphragm Pump Material
The material of the AODD pump body and diaphragm is crucial for the pump's performance and durability. Different materials are suited for different working environments and media. Common pump body materials include aluminum alloy, stainless steel, polypropylene (PP), and polytetrafluoroethylene (PTFE).
Each material is suited to specific types of liquid media:
- Aluminum Alloy: Low corrosion resistance, suitable for neutral liquids like water and motor oil.
- Stainless Steel: Strong corrosion resistance, ideal for food processing, pharmaceuticals, or mildly corrosive chemical media.
- PP: Cannot withstand high temperatures but is suitable for acidic or alkaline liquids.
- PTFE: Highly resistant to strong acids and alkalis, suitable for highly corrosive media but comes at a higher cost.
For diaphragm materials, rubber (such as natural rubber, neoprene, and nitrile rubber) is suitable for general liquids and is cost-effective, but has average durability. PTFE diaphragms offer excellent high-temperature and corrosion resistance, making them suitable for transporting strong acids, alkalis, and high-temperature fluids. EPDM (Ethylene Propylene Diene Monomer) is widely used in the food and pharmaceutical industries due to its excellent resistance to hot water and steam, making it perfect for these industries.
When selecting, users should consider both the media characteristics and the working environment to ensure the air operated double diaphragm pump performs optimally and lasts long.
Distinguish the Diaphragm Pump Media Characteristics
Pneumatic diaphragm pumps are commonly used to transfer a wide range of liquid media, such as water, oil, acidic or alkaline solutions, slurries, paints, and emulsions. When selecting a pneumatic diaphragm pump, the following factors should be considered:
- Viscosity: Low-viscosity fluids (e.g., water, dilute solutions) can be handled by most pumps. High-viscosity fluids (e.g., grease, syrup) require pumps with larger inlet and outlet sizes and stronger driving forces to ensure smooth intake and discharge.
- Corrosive Fluids: Fluids with corrosive properties should be transferred using pumps made of stainless steel or PTFE, especially when dealing with strong acids or alkalis.
- Solid Particles: Fluids containing solid particles (e.g., muddy water) need pumps with wear-resistant components.
- High-Temperature Fluids: Choose PTFE pumps for handling high-temperature fluids.
- Toxic, Flammable, or Explosive Fluids: Select pumps with good sealing and explosion-proof features for safety.
In addition to fluid characteristics, it is also important to consider flow rate and head.
Flow Rate (L/min or m/h): This represents the volume of liquid the pump can transfer per unit of time. It is the primary indicator of the pump's transfer capacity. Choose the appropriate flow range based on the actual requirements to ensure the pump can handle the workload.
Head (m): This refers to the maximum height the pump can lift the liquid. Insufficient head could prevent the liquid from reaching the intended destination. Thus, selecting the right flow rate and head is critical to ensure efficient pump operation.
Check the Inlet and Outlet Sizes
Pneumatic diaphragm pumps typically have inlet and outlet sizes ranging from 1/4 inch to 4 inches, with specific sizes available for different applications.
- 1/2 inch and 1 inch: Suitable for small equipment or laboratory applications.
- 1-1/2 inch and 2 inches: Ideal for industrial applications, such as in the chemical and coating industries.
- 4 inches and above: Suited for large-flow applications, like wastewater treatment and large-scale liquid transfer.
Before purchasing, ensure that the specifications of your existing pipeline system are compatible with the pump to ensure proper integration. Additionally, the type of connection for the inlet and outlet can be threaded, flanged, or other types. Users should choose the appropriate connection type based on their specific needs.
Select by Air Source Requirements of AODD
AODD pumps are driven by compressed air, so air pressure and air volume are key factors to consider when selecting a pump. Typically, air pressure requirements range from 3-8 bar (0.3-0.8 MPa), but the exact pressure required will depend on the AODD pump model and its operating conditions. Additionally, the air consumption of the pump is usually measured in L/min, so ensure that your air source can supply enough air volume for the AODD pump’s normal operation.
Besides air pressure and volume, the quality of the compressed air is also important. To extend the life of the AODD pump, it is recommended to use dry and clean compressed air to avoid damage to the pump components caused by moisture and impurities.
Pneumatic Diaphragm Pumps Installation and Maintenance
Proper installation and maintenance are critical to ensure the optimal performance and longevity of a pneumatic diaphragm pump. The pump can be installed horizontally or vertically, but it is essential to ensure the correct direction for the inlet and outlet to avoid air blockages that can affect the pump’s efficiency.
Regarding maintenance, regular inspections of the diaphragm, valve balls, valve seats, and other wear-prone components are crucial. If any parts show signs of wear or damage, they should be replaced promptly to keep the pump in good working condition. By ensuring proper installation and regular maintenance, you can significantly enhance the operating efficiency and lifespan of the pneumatic diaphragm pump.
When selecting an air operated double diaphragm pump, Tool.com recommends considering multiple factors, including the pump body material, media characteristics, required flow rate and head, inlet and outlet size, and air source requirements. Besides, we also provide the price list of pneumatic double diaphragm pumps for your reference. Only by ensuring that these conditions match the actual operating environment can you choose the most suitable air operated double diaphragm pump. Additionally, proper installation and regular maintenance are recommended to ensure the pump’s quality and long-term reliability.
