For effective management of any process it is important to measure, actuate, record and monitor. ABB offers a full line of field instruments and devices that can provide the necessary control and return investment.
ABB's knowledge of flow measurement and control is second to none. For decades, ABB has developed an unique understanding of customer problems and developed innovative solutions to meet them.
Range of products for flow measurement АВВ:
Electromagnetic flowmeters
U - Voltage signal B - Magnetic induction D - Distance between electrodes v - Avarege flow velocity Q - Volume flow U ~ B * D * v Q = (D2 * π / 4) * v U ~ Q |
The basis of measurements using an electromagnetic flowmeter is the Faraday law of induction, according to which, when a conductor moves through a magnetic field, voltage is induced in it.
This measurement principle is applied to the conductive fluid. The fluid supplied through the pipe, transverse to the magnetic field (see diagram).
The voltage induced in the fluid is measured by two electrodes located opposite each other. The signal voltage U is proportional to the magnetic induction B, the distance between the electrodes D and the average fluid velocity v.
Since the magnetic induction B and the distance between the electrodes D are constant, the voltage signal U is proportional to the average flow velocity v. The equation for determining the volume flow Q shows that the voltage signal U will change linearly and in proportion to the volume flow.
On the world market, ABB offers the widest and highest quality selection of electromagnetic flowmeters designed to measure the flow rate of liquids with a minimum conductivity of 0.5 μS / cm - water and aqueous liquids (pastes, acids, alkalis, juices, emulsions, etc. liquids) .
Due to the wide range of designs, materials and methods of connecting to the process, these flowmeters are suitable for almost any industrial or chemical processes and field applications where strong chemical and / or sanitary requirements must be met. A distinctive feature of these devices is their amazing operational flexibility and a wide range of models aimed at different processes.
Vortex flow meters
ABB produces two types of vortex flowmeters: VortexMaster and SwirlMaster, which differ in how they create vortex disturbances.
The work of the VortexMaster flowmeter is based on the use of a phenomenon called the Karman effect in physics.
Under the action of the flow, at the edges placed in the flow of the obstacle (flow body), alternating vortices, of a certain pulsation frequency, arise on both sides, so-called Karman vortex path. In the linear range, the frequency of the appearance of vortices behind the flow body depends only on the flow velocity, i.e., on the volumetric flow rate, and does not depend on the density and viscosity of medium.
The frequency flow pulsation is measured using a piezotransducer that converts pressure pulses into electrical pulses of the same frequency.
The frequency signal of the primary converter proportional to the flow enters the secondary converter for their further processing and conversion.
The operation concept of the SwirlMaster flowmeter is based on the fact that at the inlet of the flow former (fixed impeller), the axial movement of the measured substance is converted into rotational. In the center of rotation, the core of the vortex is formed, which is brought countercurrent flow into the secondary spiral rotation.
The secondary rotation frequency is proportional to the flow rate of working media and, due to the special geometry of the measuring channel, it is in linear dependence over a wide range of flow rates. This frequency is fixed by the piezometric sensor.
Proportional to the flow, the frequency signal of the primary transmitter enters the secondary transmitter for their further processing and transmittion.
Vortex flowmeters can be used to accurately measure the flow of gases, liquids and steam over a wide range of operating temperatures. A distinctive feature of the devices is a two-wire connection scheme in combination with digital signal processing technologies, vibration resistance and a convenient intuitive display with a built-in keyboard with the ability to control through the glass. Scope - chemical, petrochemical, gas, energy and other industries.
Differencial pressure flowmeter
In flow measurement, it is still important to use differential pressure transmitters and multivariable transmitters, because:
The multivariable transmitters, used as a flowmeter, have the following features:
Coriolis mass flowmeters
ABB's mass flow meters are based on the Coriolis principle. The model with classic parallel measuring tubes is distinguished, first of all, by its robust compact design, a wide range of nominal diameters and a relatively low price.
Measurement principle:
When the mass flows through the vibrating tube, a Coriolis force arises, bending or twisting the tube. The smallest bending of the tube is recorded and analyzed electronically using optimally positioned sensors. Since the measured phase shift of the sensor signals is proportional to the mass flow, the Coriolis flow meter allows you to directly determine the mass passing through the measuring device. The measurement principle is independent of the density, temperature, viscosity, pressure and conductivity of the media.
The measuring tubes always vibrate to resonance. This steady-state resonant frequency is a function of the geometry of the measuring tube, the properties of the material and the mass of the media oscillating in the measuring tube. It allows you to accurately determine the density of the measured media. An integrated temperature sensor records the temperature of the media and is used to correct temperature-dependent parameters of the device. A Coriolis mass flow meter allows you to simultaneously measure mass flow, density and temperature. Based on these values, other indicators can also be calculated, such as volumetric flow rate or concentration.
Function for calculation the Coriolis force ,:
Features:
Advantages
Variable area flowmeters (Rotameters)
The operating principle is based on measuring the flow rate of the media through the conical tube in which the float is vertically moving.
The position of the float in the measuring tube is proportional to the consumption at an equilibrium of the force of its weight in the medium to be measured and the force of the resistance to the moving flow acting towards it.
Distinctive features and advantages:
Design options:
Control and measurement instruments are selected individually for each technical task and, to facilitate the selection, for the most accurate description of technological requirements, it is proposed to fill out QUESTIONNAIRE (QUESTSHEET) FOR each type of equipment.
QUESTIONNAIRE FOR electromagnetic flowmeter
QUESTIONNAIRE FOR vortex flowmeter
QUESTIONNAIRE FOR torbar (flow sensor based on a Pitot tube)
QUESTIONNAIRE FOR mass flowmeter
QUESTIONNAIRE FOR variable area flow meter