The Stainless Steel Air Operated Double Diaphragm Pump (AODD) utilizes compressed air to reciprocate twin flexible diaphragms, creating positive displacement to transfer corrosive, viscous, or shear-sensitive fluids. Constructed from investment-cast 316L stainless steel, the fluid path withstands aggressive chemicals and high-purity demands.
Working Principle: Compressed air is directed by an internal air distribution valve alternately to the back of each diaphragm, forcing fluid out of one chamber while simultaneously refilling the opposite chamber. This balanced reciprocating action delivers steady flow pulsation without mechanical rotating seals.
Core Advantages:
• Packless & Seal-less Design: Eliminates mechanical seals prone to wear and leakage, preventing hazardous emissions.
• Dead-Head Capability: Can stall against a closed discharge valve without thermal overload, pump damage, or energy waste.
• Self-Priming: Dry lift capability up to 5 meters ensures immediate startup on suction lift applications.
• Shear-Sensitive Fluid Handling: Gentle pumping action avoids degrading polymers, crystal suspensions, or shear-sensitive emulsions.
• Typical Handled Media: Acids, caustic solutions, solvents, adhesives, paints, inks, high-purity pharmaceutical intermediates, and food-grade syrups.
• Typical Industries: Chemical Processing, Paint & Coatings, Wastewater Treatment, Food & Beverage, Pulp & Paper, and Pharmaceutical Manufacturing.
Technical Specifications & Selection Guide
Selecting the correct AODD pump requires balancing flow rate, pressure, and chemical compatibility. Refer to the standard configuration matrix below.
|
Model Series |
Port Size (NPT/BSPT/Flange) |
Max Flow Rate (GPM / L/min) |
Max Discharge Pressure (psi / bar) |
Max Particle Size (mm) |
Wetted Materials |
Elastomer Options |
|
SS-15 |
1/2 inch |
15 GPM (57 L/min) |
100 psi (7.0 bar) |
1.6 mm |
316L Stainless Steel |
PTFE, Santoprene, Viton, EPDM |
|
SS-25 |
1 inch |
50 GPM (189 L/min) |
100 psi (7.0 bar) |
3.2 mm |
316L Stainless Steel |
PTFE, Santoprene, Viton, EPDM |
|
SS-40 |
1-1/2 inch |
106 GPM (401 L/min) |
120 psi (8.3 bar) |
4.8 mm |
316L Stainless Steel |
PTFE, Santoprene, Viton, EPDM |
|
SS-50 |
2 inch |
235 GPM (889 L/min) |
120 psi (8.3 bar) |
6.4 mm |
316L Stainless Steel |
PTFE, Santoprene, Viton, EPDM |
Note: Custom sanitary tri-clamp connections and electropolished surface finishes (Ra <= 0.6 um) are available upon request for food and pharmaceutical applications.
Application & Fluid Compatibility Matrix
|
Fluid Type / Industry |
Recommended Wetted Material |
Recommended Elastomer |
Operating Consideration |
|
Strong Acids & Solvents (e.g., HCl, Acetone) |
316L Stainless Steel |
PTFE Diaphragm / PTFE Ball |
Use PTFE backed with Santoprene for flex life. Grounding strap required for ATEX zones. |
|
Caustic Solutions (e.g., NaOH 50%) |
316L Stainless Steel |
EPDM or Viton |
Verify temperature limits to prevent chemical attack on elastomers. |
|
Paints, Inks & Adhesives |
316L Stainless Steel |
Santoprene or Buna-N |
Handle high viscosity up to 10,000 cPs; utilize ball check valves to prevent sticking. |
|
Food & Beverage Ingredients |
316L SS (Ra <= 0.6 um) |
FDA-Compliant PTFE / EPDM |
Ensure clean-in-place (CIP) compatibility and tri-clamp port configuration. |
Manufacturing, Quality & Compliance
Material Integrity: Fluid-contact components utilize precision investment-cast CF3M (316L equivalent) stainless steel, verified via PMI (Positive Material Identification) spectrometer testing.
Machining & Tolerance: CNC vertical machining centers maintain critical fluid path tolerances, ensuring uniform internal flow and zero cavitation pockets.
Surface Treatment: Standard industrial finish features mechanical polishing; electrolytic polishing and mechanical passivation are applied to eliminate microscopic surface impurities.
Factory Testing: Every pump undergoes 100% pneumatic pressure testing and dry-run suction prime verification prior to packaging. Test logs are available upon request.
Certifications: CE compliant, ATEX Zone 1/2 rated configurations available for explosive atmospheres, and FDA-compliant fluid paths for sanitary grades.
Procurement & After-Sales Support
Minimum Order Quantity (MOQ): 1 unit for standard catalog models; OEM custom configurations negotiable.
Lead Time: 7 to 10 business days for standard stock items; 3 to 4 weeks for custom port connections or surface finishes.
Packaging: Export-grade fumigation-free plywood crates with internal moisture barrier wrapping to prevent transit corrosion.
Spare Parts Availability: Critical wear kits (diaphragms, valve balls, seats, and air valve assemblies) stocked globally for 48-hour dispatch.
Warranty: 2-year manufacturer warranty covering structural integrity of cast metal components and internal air distribution valve mechanics.
Frequently Asked Questions
Q: Can this stainless steel AODD pump run dry without damaging internal components?
A: Yes. The air distribution valve and elastomer diaphragms are engineered to withstand dry running conditions indefinitely without thermal failure, seizing, or scoring of internal surfaces.
Q: What is the maximum viscosity limit for handling high-viscosity fluids like adhesives or resins?
A: These pumps can handle fluids with viscosities up to 10,000 cPs. For fluids exceeding 5,000 cPs, flooded suction installation is recommended to ensure complete chamber filling on every stroke.
Q: How do I select between PTFE and Santoprene diaphragms for chemical transfer?
A: PTFE offers universal chemical resistance and handles aggressive solvents, but possesses lower flex life than elastomer options. Santoprene provides superior flex life and lower cost for non-aggressive water-based fluids, but is vulnerable to strong hydrocarbon solvents.
Q: Are these pumps certified for explosive or hazardous environments (ATEX zones)?
A: Yes. Groundable stainless steel models equipped with conductive PTFE diaphragms and external grounding lugs comply with ATEX Directive 2014/34/EU for Zone 1 and Zone 2 hazardous areas.
What preventive maintenance is required for continuous duty operations?
Routine maintenance focuses on inspecting the air distribution valve spool for moisture accumulation and replacing elastomer diaphragms and ball checks every 6 to 12 months depending on fluid abrasiveness and operating duty cycle.
Q: What information is required to request an official quotation or technical drawing (STEP/IGES)?
A: Please provide your fluid name, operating temperature, specific gravity, viscosity, required flow rate (GPM or L/min), discharge head pressure, and desired port connection type (NPT, BSPT, or Tri-Clamp).
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