Glossary

The key terms used in the pump world.

Flow rateالتدفق: The volume of liquid a pump moves per unit of time, usually measured in cubic metres per hour or litres per second.
Total headالرفع الكلي: The height a pump can raise a liquid to, including the level difference and pipe friction losses, measured in metres.
Friction lossفاقد الاحتكاك: Pressure lost as liquid passes through pipes, valves and bends. It rises with pipe length and flow speed.
Performance curveمنحنى الأداء: A chart showing how flow and head relate for a given pump, used to select the right model.
Duty pointنقطة التشغيل: Where the pump curve meets the system curve, giving the actual flow and head during operation.
Efficiencyالكفاءة: The share of shaft power that reaches the liquid. Higher efficiency means lower energy use.
Impellerالدفاعة: The rotating part that gives the liquid its speed inside the pump.
Volute casingالغلاف الحلزوني: The casing that collects liquid leaving the impeller and turns part of its speed into pressure.
Self-primingالتحضير الذاتي: A pump's ability to clear air from the suction line and start pumping without manual filling each time.
Cavitationالتجويف: Vapour bubbles form when pressure drops inside the pump, then collapse, causing noise and impeller damage.
NPSH: Net positive suction head. The value available on site must exceed what the pump requires to avoid cavitation.
Mechanical sealمانع التسرب الميكانيكي: A component that stops liquid leaking around the rotating shaft. Its type depends on the liquid and temperature.