VEVOR QBY4-25L F46 1-Inch Air-Operated Double Diaphragm Pump Explained

The VEVOR QBY4-25L F46 is an air-operated double diaphragm (AODD) pump with 1-inch inlet and outlet ports and an aluminium alloy body. It is powered by compressed air rather than electricity and is intended for moving liquids in workshops and industrial settings. Here is how this kind of pump works and what the stated specifications mean.

How an air-operated diaphragm pump works

An AODD pump has two flexible diaphragms joined by a shaft. Compressed air pushes one diaphragm, which draws liquid into the opposite chamber and pushes it out of the other. An air valve then switches the airflow so the diaphragms swap roles, and the cycle repeats. Because there is no motor and no rotating seal in the fluid path, this design is typically able to run dry without damage, handle liquids with some solids, and start and stop with the air supply. Pulsing flow is normal, and a low-pulsation air valve reduces it.

Flow, pressure and lift

VEVOR lists a maximum flow rate of 39.6 GPM (the title says 35 GPM), a maximum pressure of 120 psi and a maximum head lift of 275.6 ft (84 m). Maximum figures are measured under ideal conditions. In use, flow falls as the discharge height, hose length and liquid thickness increase, and with the air supply you provide. The air inlet is 1/2-inch FNPT, so the compressor must be able to supply enough air volume as well as pressure.

PTFE diaphragms and the aluminium body

The diaphragms are PTFE, a plastic widely used because it resists many chemicals. VEVOR says they are durable and corrosion-proof, with a maximum temperature of 150°F (66°C). The housing is aluminium alloy, bolted together to prevent leaks. A glyd ring gives double-acting sealing on the air side, and the air distribution system is externally accessible, with a stainless modular air valve.

What it is meant to pump

The listing says the pump can handle liquids such as waste oil, alcohol, hydraulic fluid, gasoline, diesel, detergent and drinks, across industries including petroleum, metallurgy, mining, coating, printing, water treatment and automotive. Chemical compatibility depends on the exact liquid, its temperature and the materials in contact with it, so check that against the manufacturer's information. Flammable liquids need specialist handling and suitable grounding; follow local codes and the manual.

Size and weight

The pump measures about 7.0 x 7.8 x 33.0 inches (18 x 20 x 84 cm) and weighs 18.8 lb (about 8.5 kg), light enough to be moved between jobs by one person.

Who it suits

It suits workshops, garages and industrial sites that already have a compressed-air supply and need to transfer liquids such as oils, coatings or cleaning agents.

What to check before you buy

• Your liquid: confirm it is compatible with aluminium and PTFE, and within the 150°F (66°C) limit.
• Air supply: check your compressor's pressure and air volume against the pump's needs.
• Fittings: you will need hoses and connectors for the 1-inch ports and the 1/2-inch FNPT air inlet.
• Pressure limit: keep the air pressure within the stated maximum.
• Upkeep: diaphragms and seals are wear parts, so check the manual for service intervals and spares.

The short version

• A 1-inch, aluminium-bodied, air-operated double diaphragm pump with PTFE diaphragms.
• Listed at up to 39.6 GPM, 120 psi and 275.6 ft of head lift.
• 1/2-inch FNPT air inlet; maximum liquid temperature 150°F (66°C).
• Needs a compressed-air supply and compatible hoses and fittings.

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