A metering pump moves a precise volume of liquid in a specified time period providing an accurate volumetric flow rate. Delivery of fluids in precise adjustable flow rates is sometimes called metering In every where that works with liquid chemicals like Chemical Industrial , Pools , .. The amount of element that should added to a process is very important. For this purpose Pumps that pump specific amount/dozen has been used. How many pulses per minute / hour / day / week / month can be adjusted then the pump works according to that schedule.