VEVOR QBK-15 Air-Operated Diaphragm Pump: features, specs and who it suits

The VEVOR QBK-15 is an air-operated double diaphragm pump for moving liquids in workshops and industrial settings. It runs on compressed air rather than an electric motor, which makes it a common choice for transferring oils, fuels and other low-viscosity fluids.

How a double diaphragm pump works

Two flexible diaphragms are linked together and driven back and forth by compressed air. As one diaphragm pulls, it draws fluid in; the other pushes fluid out. A pair of check valves keeps the flow moving in one direction, and an air valve swaps the air from side to side.

Pumps of this type are generally valued because they can run dry without the damage that affects some other designs, they are self-priming, and the fluid never touches a motor or spinning shaft. Flow rate depends on the air supply, the hose and the height the liquid must be lifted.

The headline specs

VEVOR rates the QBK-15 at a maximum flow of 8.8 GPM (about 33 litres a minute), a maximum head lift of 226.4 feet (69 m) and a maximum pressure of 115 psi. The listing title also states 120 PSI, so check the manual for the exact limit before connecting it to your air line. The maximum fluid temperature is 150°F (66°C).

The inlet and outlet ports are 1/2 inch, and the air inlet is 1/4 inch FNPT. The listed size is 8.3 x 5.5 x 10.6 inches (about 21 x 14 x 27 cm), compact enough to mount on a bench or cart.

Materials: cast iron body and nitrile diaphragms

The pump housing is cast iron, bolted together to prevent leaks, and VEVOR describes it as sturdy and corrosion-proof. The diaphragms are nitrile (NBR). Nitrile is typically chosen for petroleum-based fluids such as oil and fuel, while it is less suited to some strong solvents and chemicals. Always check that the materials are compatible with what you plan to pump.

The air valve

VEVOR says the pump has an externally available air distribution system with a modular stainless air valve. It describes the valve as low pulsation, giving smooth and quick changeover, and says a glyd ring provides double-acting sealing for better air performance. In practice, a modular external valve is meant to make servicing easier because it can be reached without taking the pump apart.

What it is meant to pump

The listing names waste oil, alcohol, hydraulic fluid, gasoline, diesel, detergent and drinks, and mentions industries from petroleum and mining to coating, printing and water treatment. Pumping fuels and other flammable liquids carries real hazards. Follow the manual, use suitable grounding and ventilation, and follow local codes and regulations.

Who it suits

It could suit workshops and garages with a compressor that need to transfer or drain fluids, and industrial users who want an air-driven pump where an electric motor is undesirable.

What to check before you buy

• Fluid compatibility: confirm the body and nitrile diaphragm suit the liquid, including its temperature.
• Air supply: check that your compressor can deliver the pressure and volume the pump needs, and that fittings match the 1/4 inch FNPT inlet.
• Hoses and fittings: the ports are 1/2 inch, so plan hose and clamps to match.
• Pressure limits: the listing quotes 115 and 120 psi in different places, so check the manual.
• Noise: air-driven pumps can be noisy and produce exhaust air. Check how it will be vented.
• Upkeep: diaphragms and seals are wear parts, so check availability of spares.

The short version

• An air-operated double diaphragm pump, model QBK-15, with a cast iron body.
• Nitrile diaphragms; up to 150°F (66°C).
• Up to 8.8 GPM, 226.4 ft head lift, and a listed maximum of 115 psi.
• 1/2 inch inlet and outlet; 1/4 inch FNPT air inlet.
• Intended for oils, fuels, detergents and other low-viscosity fluids; follow the manual and local codes.

Bloiq is reader-supported. Some links may earn us a commission; it never affects what we write. How we make money.