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Measuring liquid or gas flow becomes more manageable with flowmeters. As one of the most vital process control components, flowmeter types are essential in industries such as oil and gas, chemicals, food and beverages, water and wastewater, pharmaceuticals, etc.
Flowmeters, also known as flow gauges, flow indicators, or flow devices, are classified based on various parameters, including the working principle, application, medium, construction, output type, and whether or not they have moving parts.
The following are some common flowmeter types based on the working principle.
A positive displacement flow meter works by separating fluid into fixed units of measurement and then computing the number of units measured to determine flow. Its accuracy is within ±0.5%, and it works best with viscous liquids. Construction materials include stainless steel, plastic, bronze, and aluminum.
This meter measures flow by determining the average fluid velocity. Examples include turbine, electromagnetic, and pitot tube flowmeters. Velocity flowmeters have an accuracy range of ±0.5% to ±5.0% and are ideal for measuring clean or low-viscosity fluids.
Mass flowmeters measure the mass transfer rate. Coriolis mass flow meters use vibrations to measure the mass flow and density of liquids and gases. Thermal mass flowmeters work by measuring fluid heat absorption and is used mainly in gases. Mass flowmeters' accuracy is usually between ±0.1% and ±0.5%.
This type uses flow resistance to create a differential pressure, which is the amount of fluid that flows through the meter. Such flowmeters are applied to measure liquid, gas, and steam flow. Common types include Orifice plates, Venturi, Nozzle, and Pitot tubes. Differential pressure flowmeters typically have an accuracy range of ±0.5% to ±2.0%.
Using the transit time principle, ultrasonic flow meters emit ultrasonic signals, then measure the difference in time the signal takes to travel with and against fluid flow. It is used for measuring clean liquids and gases. Acoustic Doppler flowmeters determine fluid velocity using the Doppler effect and are applied to assess the flow of liquids containing suspended solids. These flowmeters feature an accuracy level of ±0.5% to ±2.0%.
Flow gauges are widely utilized across industrial sectors for multiple applications.
The Oil and Gas sector utilizes flow meters to read crude oil, natural gas, and refined oil products. Pipeline transportation, process control, and custody transfer need flowmeters.
This industry applies flowmeters for chemical production, including raw materials and finished chemical products. Flowmeters help maintain process efficiency and guarantee the correct chemical mixture ratios.
Flowmeters measure water flow in this sector and help maintain proper water treatment. In wastewater treatment, flowmeters are used to assess the flow of wastewater for treatment and discharge compliance monitoring.
Measuring liquid and gas flow in this industry keeps products' consistency and quality. Flowmeters are used in milk measurement, beer brewing, and liquid food packaging.
Accurate fluid or gas flow measurement is highly critical in drug production and distribution for this industry. Flowmeters are used to measure liquids during the drug formulation process and maintain compliance with rigorous legal quality assurance requirements.
In this industry, flowmeters are used for diverse activities, such as measuring fuel and coolant flow during machinery operation and tracking the flow of raw materials and finished goods via pipelines. Flowmeters enable manufacturers to optimize processes, reduce costs, and maintain product quality.
Flowmeters improve irrigation system water measurement, ensuring crops receive the right water amount. They measure fuel flow in agricultural machinery and assess liquid fertilizers and pesticides for accurate application in crop production.
Flowmeter selection depends on these key specifications:
This indicates the minimum and maximum flow rates the meter can measure. Choosing a meter with the correct flow range is vital to ensure accurate readings within the operational flow rate.
Understanding the fluid type to be measured, whether liquid, gas, or steam, is critical, as some flowmeters work better with specific fluids. Meter selection also considers fluid viscosity, density, and temperature.
Consider the installation orientation (horizontal or vertical) and the space constraints where the meter will be installed. Some flowmeters require straight pipe lengths for accurate readings, while others tolerate bends or fittings.
Flowmeter materials must have compatibility with the fluid medium to prevent damage. Common construction materials include plastic, stainless steel, aluminum, and bronze.
Flowmeters generate readings that require output formats such as 4-20mA, pulse, and frequency. Some meters feature advanced communication protocols for integration with process control systems. The output type depends on the application and system requirements.
Positive displacement flow meters are ideal for measuring high-viscosity liquids like oils, syrups, and molasses. In contrast, low-viscosity liquids and gases such as water, air, and natural gas work ideally with turbine flowmeters. Flowmeters with moving parts usually apply to clean fluids, while those with no moving parts are best suited for fluids containing solids or impurities. Coriolis and thermal mass flowmeters suit applications where precise mass flow measurement is vital, and differential pressure flowmeters are best for high-temperature and high-pressure environments.
In selecting flowmeters for clients, B2B buyers should consider these vital factors:
What the flowmeter will be applied for should be the foremost consideration. Some flowmeters are designed for specific applications, such as custody transfer in oil and gas or billing in water treatment.
B2B buyers should collect information about the fluids that will pass through the flowmeters. This includes whether they are liquids, gases, or steam, and their viscosity, density, temperature, and pressure. Every flowmeter type suits particular fluids, so buyers should prioritize those which are compatible.
Most industries have certain flowmeter standards. For instance, oil and gas apply API standards, while water and wastewater treatment follow AWWA guidelines. Pharmaceutical and food and beverage industries demand flowmeters featuring sanitary designs that meet strict hygiene standards. B2B buyers should pay attention to applicable standards and select flowmeters that comply with them to ensure legal and safety adherence.
Buyers should consider the needed accuracy level and ensure the chosen flowmeter meets them. The flowmeter's measurement range must also be in line with the expected flow rates of the fluids. Using a meter outside the required range may lead to inaccurate measurements.
Flowmeter maintenance frequency should be considered. Some need high maintenance, while others are low. Buyers to keep in mind the operational environment, whether it is harsh or not, and select flowmeters that can withstand chemical, temperature, and pressure extremes. Durable flowmeters also reduce maintenance requirements.
Although the initial flowmeter costs are important, buyers should analyze the total ownership costs, maintenance, and durability, and choose the option with the lowest life cycle costs.
A1: Coriolis mass flowmeter has the highest accuracy of ±0.1% among all flowmeters.
A2: Not all flowmeters have moving parts. Some like electromagnetic and ultrasound are based on sensing principles, while others like turbine and piston have moving parts.
A3: Yes, some flowmeters like differential pressure and ultrasonic can measure both liquids and gases. But most like positive displacement and turbine work better with one fluid type.
A4: Flowmeters last for five to 10 years, depending on the fluid passing through them, operating conditions, and maintenance practices.
A5: When the flowmeter starts displaying numbers and units of measure varying erratically or outside normal limits, it is malfunctioning. Also, inaccurate readings, failure to communicate, strange noises, and the presence of physical damage indicate a malfunctioning flowmeter.
