Working Principle
The PVDF Diaphragm Pump operates via the reciprocating action of two flexible diaphragms mounted on a common shaft. Driven by compressed air (AODD) or a motor-driven gearbox (Electric), this movement creates a suction stroke that draws fluid into the chamber and a discharge stroke that forces it out. The fluid path is entirely isolated from the drive mechanism by the diaphragms, eliminating dynamic shaft seals and preventing external leakage.
Core Advantages
• Chemical Inertness: Solid-machined or virgin-molded PVDF (polyvinylidene fluoride) liquid ends withstand aggressive acids, halogens, and chlorinated solvents up to 100°C.
• Seal-less Construction: Eliminates mechanical seal failures and fugitive emissions, which is critical for safe hazardous chemical transfer.
• Dry-Run Capability: Can run dry indefinitely without damaging internal components or generating excessive heat.
• Variable Flow and Pressure: Adjustable discharge pressure and flow rate simply by regulating inlet air pressure or motor speed, requiring no bypass valves.
• Low Shear Pumping: Gentle displacement action preserves the viscosity and structural integrity of shear-sensitive fluids and slurries.
Typical Handled Media & Industries
• Media: Concentrated Hydrochloric Acid (HCl) up to 37%, Sulfuric Acid (H2SO4) up to 98%, Sodium Hypochlorite (NaOCl), Nitric Acid (HNO3), Hydrofluoric Acid (HF), and Deionized Water/Ultrapure Solutions.
• Industries: Chemical Processing & Distribution, Water & Wastewater Treatment, PCB Manufacturing & Metal Finishing, Semiconductor Wet Bench Equipment, and Pulp & Paper Bleaching.
Technical Specifications & Material Selection
|
Technical Parameter |
Standard Specification Range |
|
Body Material |
Virgin PVDF (Injection Molded / CNC Machined) |
|
Diaphragm Options |
PTFE with EPDM/FKM backer, TFM, or Pure PTFE |
|
Max. Flow Rate |
0 to 560 L/min (0 to 148 gpm) |
|
Max. Discharge Pressure |
8.3 bar (120 psi) |
|
Max. Operating Temperature |
100°C (212°F) |
|
Port Connections |
ANSI / DIN Flanged, NPT/BSP Threaded |
|
Max. Solid Particle Size |
1.5 mm to 9.5 mm (Model dependent) |
Manufacturing, Quality Control & Global Compliance
Precision CNC Machining:
Fluid manifolds and center blocks are machined from solid PVDF billets on 5-axis CNC centers to maintain tight dimensional tolerances and eliminate micro-porosity common in low-grade injection molding.
Hydrostatic Pressure Testing:
Every assembled pump undergoes a 1.5x working pressure pneumatic and hydrostatic test prior to factory dispatch.
Traceability:
Material test reports (MTRs) for PVDF pressure-retaining components are supplied per EN 10204 3.1 upon request.
Global Certifications:
CE compliant, ATEX Zone 1 / 2 certification available for explosive environments, and FDA-compliant fluid path options for food/pharmaceutical chemical dosing.
Application & Selection Guide
To select the correct PVDF diaphragm pump for your installation, evaluate the following operational parameters:
Chemical Compatibility: Cross-reference fluid concentration and operating temperature against PVDF and PTFE chemical resistance charts.
Total Dynamic Head (TDH): Calculate static elevation, friction losses in piping, and discharge pressure requirements. Ensure required pressure does not exceed 8.3 bar.
Viscosity & Specific Gravity: Adjust required motor/air power if handling fluids with a specific gravity greater than 1.0 or viscosity exceeding 5,000 cp.
Suction Lift & Performance Curves: Verify available Net Positive Suction Head (NPSHa) against pump requirements and cross-check operating points against factory Flow-Rate vs. Air-Pressure Performance Curves to prevent cavitation and ensure optimal efficiency.
Frequently Asked Questions
Q: Can PVDF diaphragm pumps handle concentrated sulfuric acid at elevated temperatures?
A: Yes. PVDF exhibits excellent resistance to concentrated sulfuric acid (H2SO4) up to 98% concentration at temperatures reaching 100°C. However, review specific corrosion data if operating near the upper temperature limit combined with high discharge pressures.
Q: What is the maximum dry-suction lift for this pump?
A: Depending on the specific model size and diaphragm condition, standard dry self-priming capability ranges from 3.0 meters to 6.0 meters of water column. Wet priming lift increases by approximately 20%.
Q: Are the fastener bolts in contact with the corrosive fluid?
A: No. The pump design isolates external hardware (such as stainless steel or coated tie-rods) from the internal liquid path. Only virgin PVDF and PTFE/diaphragm elastomer surfaces contact the pumped chemical.
Q: How do I prevent diaphragm fatigue in continuous 24/7 chemical duty?
A: Select PTFE-faced diaphragms with an elastomer backup (such as EPDM or FKM). The PTFE provides chemical resistance while the elastomer absorbs mechanical stress. Operating the air supply at the lowest effective pressure also extends diaphragm service life.
Q: What documentation is provided for pressure-retaining components?
A: We supply full material traceability certificates (EN 10204 3.1), hydrostatic test reports, and FDA conformity declarations for fluid-contact parts upon request during order placement.
Q: What is the standard lead time and shipping compliance for international orders?
A: Standard catalog configurations (ANSI/DIN flanged, PTFE/EPDM diaphragms) typically ship within 5 to 10 working days. Custom configurations or ATEX-certified units require 2 to 3 weeks for final assembly and testing. All exports utilize ISPM 15 compliant wooden packaging.
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