A turbine flow meter is one of the most popular and one of the simplest methods of measuring flow. It is most commonly used to measure liquid, which includes chemicals and water, but also measures gas. Electromagnetic flow meters are more commonly used for water measurements. There are varieties of turbine flow meter that are even ideal for measuring the dispense of drink or beer.
A free-spinning magnetic rotor spins as fluid passes and small voltage pulses are generated in a magnetic coil sensor mounted in the wall of the flowmeter body. The rotational speed of the rotor and the frequency of the generated voltage pulses are directly proportional to flow rate. Due to magnetic drag at low velocities, the turndown range of the turbine is usually limited to around 10:1.
As with all flow meters, care should be taken to ensure a turbine flow meter is the correct choice for the required duty. Whilst offering many advantages, the turbine has one Achilles’ heel: it is very sensitive to changes in liquid viscosity. If the viscosity of the metered liquid changes, perhaps due to change in temperature, this will have an effect both on the number of pulses generated per litre and the linear operating flow range. These changes will ultimately show as an increased measuring error. Typically, turbines can be used with liquids which have working viscosities up to around 10 mPas where the full 10:1 flow range is required, or up to 50 mPas when the flowmeter will operate at a fixed flow rate (usually in a batch process). Coriolis flow meters measures mass flow with accuracy unaffected by changes in fluid density or flow profile.
The turbine flow meter is usually referred to as the ‘primary’ element in a flow measurement system. Its output signal is fed to a ‘secondary’ device which can interpret the pulses and give a meaningful display of flow rate, total and other variables.
Because these flow meters are quite small in both size and weight, they are often used as portable test equipment. They can be fitted with an integral, battery-operated flowrate indicator/totaliser, such as the Contrec Model 102D, and carried in a Peli case in the boot of a car.
A turbine flow meter has great flexibility and can provide a flow measuring solution at a very affordable price. They can be used in a variety of different industries for liquids and gases. Typical applications for turbine meters include hygienic mixing and batch control in dairies distilleries, breweries and food manufacturing, tanker loading, gas measurement, water and waste water measurement, monitoring fuel consumption and precision measuring in cryogenics. They are easy to install and maintain, and provide a convenient signal output compatible with a wide range of flow instrumentation.
Flowquip’s range of high accuracy turbine flow meters include hygienic meters for use in food and pharmaceutical industries, stainless steel flow meters with good corrosion-resistance for use with hazardous fluids, and gas turbine flow meters.
A Certificate of Calibration is supplied with every new turbine flow meter offered by Flowquip. Over time the output signal, pulses per litre, will change slightly due to wear. For this reason, we recommend turbines are returned to us after one to two years’ service for overhaul and recalibration. We provide a dedicated flow meter overhaul and calibration service. Flow meters can be returned for repair or overhaul and our certified, purpose-built, in-house calibration rigs enable most types of flow meter, including a turbine flow meter, to be re-calibrated if required and a new calibration certificate issued.
If you want to know more about how a turbine flow meter could help you, or you would like more information on any of Flowquip’s products or services, get in touch. We would love to help.