Reference image. Final construction follows the confirmed model and quotation.
Pneumatic Diaphragm Pumps
QBY3-25A Air Operated Double Diaphragm Pump
Model: QBY3-25A
QBY3-25A air-operated double-diaphragm pump for chemicals, slurry, viscous liquids and industrial transfer. Catalog performance reaches 40 gpm (151 L/min) at up to 120 psi (0.84 MPa, 8.4 bar), with 1 in fluid connections.
TECHNICAL DATA
Specifications, performance and construction
Confirm the final operating point, materials, motor and connection standard before ordering.
QBY3-25A series overview
QBY3-25A air-operated double-diaphragm pump for chemicals, slurry, viscous liquids and industrial transfer. Catalog performance reaches 40 gpm (151 L/min) at up to 120 psi (0.84 MPa, 8.4 bar), with 1 in fluid connections.
The QBY3 uses compressed air as its power source and has no rotary shaft seal. It can self-prime, run dry within approved conditions, handle suspended solids and transfer corrosive, volatile, flammable or viscous liquids when the correct wetted materials are selected.
Catalog technical parameters
| Model / series | QBY3-25A |
|---|---|
| Maximum flow | 40 gpm (151 L/min) |
| Maximum working pressure | 120 psi (0.84 MPa, 8.4 bar) |
| Fluid inlet / outlet | 1 in |
| Air inlet | 1/2 in |
| Maximum dry suction | 18 ft (5.48 m) |
| Maximum wet suction | 18 ft (5.48 m) |
| Maximum permitted solids | 1/8 in (3.2 mm) |
| Maximum air consumption | 60 scfm |
| Displacement per cycle | 0.15 gal (catalog value) |
| Maximum reciprocating speed | 276 cpm |
QBY3-25A model pictures, specifications and installation dimensions
This high-resolution technical sheet is matched directly to the QBY3-25A page in the official DFIN catalog. Open it to inspect material versions, outline dimensions and mounting details.
QBY3-25A air-consumption and fluid-flow performance curves
Use the catalog curves as preliminary selection data. Final capacity depends on air pressure, discharge pressure, piping loss, viscosity, solids and selected elastomers.
Download complete QBY3 catalog (PDF) ↓
Pump-body and diaphragm material options
| Pump body | Aluminum alloy (L), stainless steel (B), cast iron (Z), rubber lined (ZCJ), engineering plastic (PP/PVDF), fluorine lined (CF) |
|---|---|
| Diaphragm | Buna-N / NBR, neoprene / CR, Viton / F, PTFE / F46, EPDM, synthetic plastic / PP |
| Connection options | NPT, BSPT and selected flanged configurations according to size and body material |
Typical applications
- Petrochemical and chemical transfer
- Paint, ink, printing and papermaking
- Food, pharmaceutical and sanitary support duties
- Environmental protection, sludge and wastewater
- Metallurgy, ceramics, mining and abrasive slurry
- System flushing and hazardous-area transfer
Selection and ordering notes
- Confirm liquid name, concentration, viscosity, temperature and solids before selecting body and diaphragm materials.
- Provide the required flow, discharge pressure or total head, suction condition and operating air pressure.
- Confirm fluid-port standard, air-inlet size, preferred center-port or side-port arrangement and installation dimensions.
- Catalog maximum values are limits, not a recommended duty point. DFIN will verify the final selection against the performance curve.
SELECTION SUPPORT
Application-based pump selection
Send the liquid, flow, head or pressure, temperature, solids, installation, power supply and destination for a verified recommendation.
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