ABSTRACT
Flow is one of the most important physical parameters measured in industry and water management. ere are various kinds of owmeters available, depending on the requirements dened by the dierent market segments. For many years, dierential pressure types of owmeters have been the most widely applied ow measuring device for uid ows in pipes and open channels that require accurate measurement at reasonable cost. In markets like waterpower, water supply, and irrigation, however, ow must be measured without any head losses or any pressure drop. is means there are no moving parts, no secondary devices, nor any restrictions allowed. Two types of owmeters presently fulll this requirement: electromagnetic and ultrasonic owmeters. Whereas ultrasonic flowmeters can be applied in nearly any kind of owing liquid, electromagnetic owmeters require a minimum electric conductivity of the liquid for operation. In addition, the cost of ultrasonic owmeters is nearly independent of pipe diameter, whereas the price of electromagnetic owmeters increases drastically with pipe diameter.
