Reinhard Woltman invented the first turbine flow meter way back in 1790. In order to study the loss of water flow velocity in open canals, he came up with the idea of the turbine flow meter. It has been the subject of many technological innovations since then, but the original design remains the preferred method when measuring water flows in large quantities. It is known as the Woltman flow meter.
There are now eight different types of Turbine Flow meter available due to technological developments. Some flow meters are named for the type of water wheel they are based on, others are named for the technology they use. Broadly speaking, the following types of turbine flow meters are currently in use:
Based on the original Pelton wheel that used flowing water to turn turbines, the Pelton wheel has buckets attached to the outside of the wheel. The Pelton wheel rotates when water or liquid hits these buckets. In a more compact frame, the Pelton wheel turbine flowmeter measures low viscosity liquid flow that occurs at a slow rate using a similar setup.
Flow meters with paddle wheels are based on water wheels. They have shafts that are positioned at right angles to the flow stream. As the shafts are rotated by the flow, they are attached to a lightweight paddle wheel. Flow meters with paddle wheels are more effective for low-speed flows because the speed of rotation of the paddle wheel depends on the flow speed of the liquid.
This type of flowmeter is based on the propeller turbine principle, which is commonly used to generate hydroelectric power. A propeller turbine, invented by Forrest Nagler in 1916, has three to six blades and looks like a wooden propeller. They have fixed blades that rotate around a central axis. The advantage of propeller flowmeters is that they have fewer blades, which means they are less likely to be damaged by debris. Additionally, they are extremely inexpensive and do not require electricity to measure flow rates.
In municipal and industrial water applications, Wolftman meters remain widely used for measuring flow rates of large volumes of water. Their invention was the first turbine flow meter. The axis of these meters is aligned with the direction of flow, resulting in highly accurate readings.
Such types of meters are mainly used for billing purposes in residential and commercial water supply operations. They consist of a set of blades positioned directly in the path of a stream or jet of water.
Flowmeters that use multi-jet technology use water from multiple orifices to rotate blades around a central axis. Multi-jet meters are used for both residential and commercial water supply billing.
Compound flow meters are a hybrid between Turbine Flow meter and positive displacement meters. In addition to the turbine component, it also includes a positive displacement component. High flow rates are measured by the rotation speed of the turbine while low flow rates are measured by the displacement component. In apartment buildings with fluctuating water flow rates during the day and at night, hybrid meters are widely used to measure water flow rates.
In an axial flow meter, a turbine or rotor rotates around the flow axis, hence its name. They are mainly used for measuring the flow of petroleum products, industrial liquids, and gases. Axial flow meters come in different designs depending on what they are used for.
What is the best type of flow meter for industrial use?
In order to choose the best flow meter for industrial use, you should first understand what they are and how they work. Turbine flow meters are composed of rotor blades that are arranged at an angle on a shaft. Fluid flowing through the blades turns the shaft, which is sensed by a mechanical reader, while magnetic pulses are detected by a magnetic reader. It is ideal for measuring gases and liquids where blades and rotors move in proportion to liquid movement. However, non-lubricating fluids require special consideration. If the meter is intended to measure these fluids, the blades are usually greased. As for measuring natural gas transmission, the blades can only withstand temperatures up to 60 degrees Celsius.
In addition to corrosive and clean liquids, turbine flow meters are ideal for water, petroleum, and chemicals. The diameter of the pipe should not exceed 24 inches. A concrete foundation is required for large flow meters. If the flow rate is low, the accuracy of turbine flow meters decreases. On the other hand, high speed liquids cannot be measured with this type of meter. Rotor blades get worn out or damaged by this. Non-lubricating fluids wear out the flow meter, resulting in inaccurate readings. Dirty fluids cannot be measured by the flow meter, too.
A magnetic flow meter measures fluid flow by following a concept known as Faraday’s Law. As a result, the meter does not contain moving parts. Essentially, a magnetic field generates voltage proportional to the velocity of liquid particles when they move through it. As opposed to its turbine counterpart, this meter can measure dirty liquids, highly corrosive acids, and water with ease. An electronic reader picks up this signal and processes it. Hydrocarbons and distilled water cannot be used with it, however.
In addition to measuring clean, dirty, abrasive and corrosive liquids, magnetic flow meters can also be used in a variety of applications due to their non-obstructive nature. Only gases are non-conductive, so these meters work best when low maintenance work is needed. Most industrial applications release dirty water as part of their waste. They are the best option for pressure drop in liquids. Papermaking, power generation, mineral processing and chemical industries use this type of meter. Water and sewerage utility companies also use it.
The Best Flow Meters for Domestic and Industrial Use
The purpose of flow meters is to measure the flow of gas or fluid. They’re used in a variety of applications, including leak detection, pressure control, and even asthma attack prevention.
Let’s examine how mechanical, ultrasonic, pressure, and electromagnetic devices are powered.
Mechanical flow meters
In basic types, turbines or wheels are inserted into pipes, measuring velocity and calculating volumetric flow based on the area of the pipes.
A mechanical flow meter can consist of a variety of types, including piston meters – which use rotating pistons – gear meters – which use two or more gears rotating at right angles – and single jet meters – which use impellers to increase or decrease liquid flow.
Ultrasonic flow meters
Compared to mechanical flow meters, ultrasonic flow meters offer several advantages. Since they don’t use mechanical parts, maintenance of such devices is relatively low due to the lack of mechanical parts. They can be used to measure all sorts of liquids, including molten sulfur, water, chemicals, and others. In addition to being much more reliable than mechanical systems, they’re also much quicker to use since they don’t have to be inserted into a pipe but are clamped to the outside.
Ultrasonic meters come in two kinds: Doppler and transit. Both use transducers to measure flow, but in different ways. A Doppler shift occurs when disturbances in the liquid influence reflection. The shift is equal to the flow rate. By contrast, transit meters use transducers that transmit signals from opposite sides of a volume of liquid. The difference between the two signals provides the flow rate.
Pressure-based flow meters
A differential pressure or dynamic pressure determines flow rate in pressure-based flow meters, such as Pitot tubes, cone meters, and Dall tubes.
Differential pressure involves squeezing a pipe to create a drop in pressure. As more liquid is introduced, more pressure is created. The flow rate is determined by the difference between upstream and downstream pressure values.
The dynamic pressure is calculated by measuring the difference between static pressure (the pressure at a stagnation point) and stagnation pressure. Get more info about gas flow meter.
Electromagnetic flow meters
As magnetic fields are created in a section of a pipe, changes in voltage are created by the fluid’s conductive particles. These changes are then used to determine the flow rate.
Water-based liquids like wastewater can be measured using such meters, but hydrocarbons, oil, and distilled water cannot.
A number of variables need to be considered when selecting flow meters. Since one type may not work on certain gases or liquids, choosing the wrong device can cost a lot of money. There are a number of questions to answer, including what liquid/gas will be measured, the viscosity (if it is not water-based), and the amount of impurities. Another factor to consider is the size, material, upstream/downstream turns and valves of the pipe.