There are distinct differences in functionality, accuracy, and certainly price. Ultrasonic sensors that accurately and non-invasively measure through commonly used tubing is an excellent multi-use option that is positioned on the higher end of the price scale. If low unit price is desirable without sacrificing accuracy, then single-use turbine type sensors are a good option particularly if working fluid is low viscosity. If higher viscosity working fluids are involved, the single-use flow through disposable ultrasonic sensors are the best fit.

When selecting a flow meter consideration must be given to:

Flow measurement type - momentum (velocity), volumetric or mass flow measurement

Accuracy - required accuracy of the readings

Environmental considerations - special installation considerations such as hygienic installation, installing in to an ATEX zone or requiring tamper proof readings

Media - type of media (liquid, gas or slurry) and any special condition such as particulates in the media and viscosity of the media

Media conditions - pressure and temperature of media and whether media conditions are likely to remain constant or vary

Flow range - required flow range of media

Here is an overview for some of the flowmeter options:

Coriolis flowmeters offer true mass flow measurement through two designs: a single tube or two parallel tubes. They operate via an oscillation which is induced in the tube(s) at a reference frequency.Among the most accurate of technologies available, Coriolis flowmeters are suitable for a wide and growing range of gas and liquid applications. These devices provide multiparameter data on mass, density, and temperature. They are used in pharmaceutical manufacturing, wastewater treatment facilities, nuclear facilities, natural gas measurement and custody transfer.

Ultrasonic flow meters offer more advanced technology and greater versatility than some other types. These designs measure the frequency shift of an ultrasonic signal that is sent through the fluid. Two types of ultrasonic meters are Doppler and transit-time. Doppler technologies utilize particles or aeration in the fluid as a reflective mechanism to gauge the velocity of the fluid. Transit-time technologies rely on a frequency difference in forward and reverse signals sent though a clean liquid to gauge the velocity of the fluid; the fluid must not have solids or aeration, as they will distort the sonic pulses. 

Because of their versatility and advantages of ultrasonic flow meter, ultrasonic flowmeters are used in a long list of industries, including facilities management, pulp and paper manufacturing, chemical manufacturing, and mining. Water/wastewater, petrochemical, and aquafarms also enlist this technology. Ultrasonic meters can be used to measure the corrosiveness of slurry fluid flow.

Magnetic meters (or magmeters) are available in two design styles: insertion and full-bore. Coils in the meter produce a magnetic field. When a conductive fluid is passed through the field, a voltage is produced through an electrode in the meter wall or insertion probe; this generated voltage is proportional to the flow. Magmeters operate by measuring the electrical content of water or other fluids. The magnetic technology contains no moving parts, and the full-bore designs offer no intrusions into the flow stream. Magmeters are high end flow meters and are used in the food & beverage industry, water purification, pulp and paper manufacturing, mining, chemical manufacturing, and petrochemical industries. They should not be used with low conductivity fluids such as de-ionized water.

Turbine meters contain a bladed rotor positioned along the centerline of the flow stream. The rotating component is designed to provide a pulse when passing either a magnetic or optical sensor. The frequency of the pulses is proportional to the velocity of the fluid. Some designs offer high levels of accuracy and can handle slightly higher viscosity fluids than basic propeller-type designs. Also, some turbine designs meet sanitary guidelines.

Irrigation and water purification are two common applications for turbine flowmeters. They are also used in the oil and gas, utilities, and wastewater industries. When used with sanitary connections, turbine meters control flow in food & beverage applications.