Direct mass measurement principle sets Coriolis flowmeters apart from other technologies as mass measurement is not sensitive to changes in pressure, temperature, viscosity and density. Ability to measure liquids, slurries and gases makes Coriolis flowmeters the universal ones.
This type flowmeters use the Coriolis effect to measure the amount of mass moving through the element. The fluid to be measured runs through a U-shaped tube that is caused to vibrate in an angular harmonic oscillation. Due to the Coriolis forces, the tubes will deform and an additional vibration component will be added to the oscillation. This additional component causes a phase shift on some places of the tubes which can be measured with sensors.
The thermal mass flowmeter operates independent of density, pressure, and viscosity. Thermal meters use a heated sensing element isolated from the fluid flow path where the flow stream conducts heat from the sensing element. The conducted heat is directly proportional to the mass flow rate and the temperature difference occurred is calculated to mass flow.
The accuracy of the thermal mass flow device depends on the calibrations reliability of the actual process and variations in the temperature, pressure, flow rate, heat capacity and viscosity of the fluid.
Vortex flow meters, also referred as as vortex shedding flow meters or oscillatory flow meters, measure the vibrations of the downstream vortexes caused by a barrier in the moving stream. An obstruction in a fluid flow creates vortices in a downstream flow. Every obstruction has a specific critical fluid flow speed at which vortex shedding occurs. Vortex shedding is the instance where alternating low pressure zones are generated in the downstream.
An electromagnetic flow meter operates on Faraday's law with electromagnetic induction that states that a voltage will be induced when a conductor moves through a magnetic field. The liquid serves as the conductor and the magnetic field is created by energized coils outside the flow tube.
The voltage produced is directly proportional to the flow rate. Two electrodes mounted in the pipe wall detect the voltage which is measured by a secondary element.
Ultrasonic Doppler Flow meter operation is based on phenomenon of reflected signal frequency modification by the velocity and direction of the fluid flow.
If a fluid is moving towards a transducer, the frequency of the returning signal will increase. As fluid moves away from a transducer, the frequency of the returning signal decreases.
The orifice meter consists of a flat orifice plate with a circular hole drilled in it. There is a pressure tap upstream from the orifice plate and another just downstream. There are in general three methods of placing the taps. The coefficient of the meter depends upon the position of taps.
With an orifice plate, the fluid flow is measured through the difference in pressure from the upstream side to the downstream side of a partially obstructed pipe. The plate obstructing the flow offers a precisely measured obstruction that narrows the pipe and forces the flowing fluid to constrict.
Due to simplicity and dependability, the Venturi tube flowmeter is often used in applications where it's necessary with higher TurnDown Rates, or lower pressure drops, than the orifice plate can provide.
In the Venturi Tube the fluid flowrate is measured by reducing the cross sectional flow area in the flow path, generating a pressure difference. After the constricted area, the fluid is passes through a pressure recovery exit section, where up to 80% of the differential pressure generated at the constricted area, is recovered.
Despite of differences in design all the turbine flow meters are based on the same simple principle:
When fluid starts to moves through a pipe and acts on the turbine vanes, the turbine start to spin and rotate. The rate of spin is measured to calculate the flow. The turndown ratios may be more than 100:1 if the turbine meter is calibrated for a single fluid and used at constant conditions. Accuracy may be better than ±0,1%.
Argosy Technologies provides wide range of flow computers, an electronic computational device implementing the algorithms required to process the raw data received from flow meters to which it is connected into volumes at base conditions.
They flow computers are also perform:
RTDs operate by exhibiting an increase in resistivity with an increase in temperature. RTDs are most commonly made from platinum, nickel, or copper. Copper and nickel versions operate at lower temperature ranges and are less expensive than platinum. Platinum is the most versatile material because of its wide temperature range (–200°C to 850°C), excellent repeatability, stability, and resistance to chemicals and corrosion. Platinum RTDs are available in 100 (omega), 200 (omega), 500 (omega), and 1000 (omega) nominal resistance values at 0°C, of which the 100 (omega) is the most popular.
Force Collector Types These types of electronic pressure sensors generally use a force collector (such a diaphragm, piston, bourdon tube, or bellows) to measure strain (or deflection) due to applied force (pressure) over an area.
Some types of electronic pressure sensors use other properties (such as density) to infer pressure of a gas, or liquid.