Pumps, Sprayers and Inflators

Let the fluid and the supply choose the pump

Start with the power source. The current type field separates manual hand pumps, DC pumps for 12 V systems, battery-powered units, often lithium-ion, and mains-powered pumps. A 12 V pump suits an RV or boat, a manual pump suits occasional jobs, and a cordless unit suits work far from power. Then match the fluid: water, fuel, oil and chemicals each need compatible casings, impellers and seals.

Material choices follow the fluid. Plastic casings and impellers suit clean water, while aluminum or stainless steel resist heat and wear. Nitrile seals resist oils and many fuels, but some solvents and strong chemicals attack them, so check the compatibility chart for your fluid. Never use a pump on fuel unless it is rated for fuel, because sparks and incompatible seals are dangerous.

Seals, baskets, filters and oils: matching parts by number

Many items here are service parts. Mechanical seals are chosen by shaft diameter and the pump series, strainer baskets and diaphragms by the pump model, and filters by cross-reference number. Match the part number or the pump's model plate rather than the picture. Where a listing says it fits certain brands or models, read those lines closely; a part for a similar-looking model may not seal.

Lubricants are graded by viscosity. Hydraulic oil at ISO 68 and gear oil at 80W-90 are different products, and each must match the pump or gearbox maker's specification. Biodegradable and mineral oils should not be mixed without checking compatibility. Grease and chain lubricants are chosen by temperature range and whether the part is exposed to water.

Questions about Pumps, Sprayers and Inflators

What does ISO 68 mean on hydraulic oil?

It is the viscosity grade: ISO VG 68 means the oil has a kinematic viscosity of about 68 centistokes at 40 degrees C. Thicker grades flow more slowly. Use the grade the equipment maker specifies, because the wrong one can cause wear or overheating.

Can I use a water pump for fuel or chemicals?

No, not unless it is rated for them. Seals, impellers and casing materials that handle water can swell, crack or corrode in fuel or solvents, and an ordinary motor can ignite fumes. Pick a pump whose listing states the fluid it is built for.

How do I pick between a 12 V DC pump and a mains pump?

Use 12 V DC where you have a battery, as in an RV, boat or vehicle, and mains power where there is a socket. Check the pump's flow and pressure at the voltage you have, and size the wiring and fuse to its current draw, because 12 V pumps draw high currents.