Glossary of Pumping Terminology

Bagging

A generic (and a little ambiguous) term for pump hose. Generally taken as layflat hose, but can be applied to any type of suction or delivery hose.

Delivery Hose

The hose used on the outlet side of a pump which delivers water to the discharge point.

Flow Rate

The volume of water a pump can deliver in a given time. Generally expressed in litres per minute or cubic meters per hour (1 l/m = 0.06 m3/h).

Friction Loss

The increase in pressure at the pump outlet caused by turbulence as the water flows through hose, pipes, connectors and other fittings. This results in a reduced pressure at the hose discharge point (and hence reduced flow). Friction loss is affected by flow rate, hose diameter, length and material roughness. In general, using the largest diameter and shortest length of hose possible gives the least friction loss. (See our Friction Loss Calculator)

Impeller

A rotating set of vanes mounted on a disc which (in conjunction with the volute) converts the energy from the engine or motor to flow.

Layflat Hose

Lightweight and convenient delivery hose which rolls flat when not in use. Available in various inside diameters such as 25 mm (1″), 32 mm (1¼”), 38 mm (1½”), 51 mm (2″), 76 mm (3″), 102 mm (4″) & 152 mm (6″).

Maximum Theoretical Suction Lift

The theoretical maximum vertical distance a pump can lift water. Assuming the pump is at sea-level, that it produces a perfect vacuum, and there are no friction losses, the maximum theoretical suction lift is 10.3 m. At this point, the weight of water in the suction hose equals the force exerted by the atmospheric pressure. (See How Does an End-Suction Pump Work?)

Pressure

Defined as force per unit area and is usually given in pounds per square inch (psi) or kilograms per square centimetre (kg/cm²).

Road Ramp

Our unique, registered design which allows water to be pumped across roads and pathways without costly removal and reinstatement the road surface and without restricting the flow of traffic. (See Road Ramp)

Static Suction Head

The vertical distance from the water line to the centre-line of the impeller.

Strainer

A fitting installed on the end of the suction hose, submerged under the water, which prevents items larger than the solids handling capability of the pump from entering the system and potentially causing damage.

Submersible Pump

A pump designed to be submerged underwater – has the advantage of eliminating the maximum suction lift problem, making it suitable for static suction lifts greater than 9 m. Also, since no suction hose is required, can be engineered into compact units for simple drainage applications.

Viscosity

A measure of a fluid’s resistance to flow. A fluid with a high viscosity will have a large amount of internal friction and will resist motion/flow, conversely a fluid with a low viscosity has low internal friction and therefore will flow more easily.

Consider pouring honey and water – the honey has a higher relative viscosity than the water and will resist the flow.

In general, the viscosity of a fluid decreases as temperature increases. The viscosity of water is approximately 1 mPa s at 20°C.

Volute

A spiral shaped casing which houses the impeller and functions to increase the pressure at the discharge port. The volute is essentially a curved funnel which increases in area at the discharge port, the effect of which reduces the flow rate and increases pressure.