What is a flow meter?
Flow meter orflow metermeans by which to measure linear, nonlinear, mass or volumetric flow rate of gases or fluids can be used.
When choosing a flowmeter for a particular industrial unit, considerations such as familiarity with factory workers, their experience in calibration, maintenance, access to spare parts, average time between failure history, and. Should be considered.
It is recommended that installation cost considerations be considered after these steps.
One of the major mistakes in flow measurement is reversing this trend:
Instead of choosing a device that works properly, they try to justify choosing a cheap device for economic reasons. Such ” cheap flow meter ” purchases can have high setup and installation costs.
Flow meters are divided into two basic types:
Water flow meter
Dubai air gauge
Flowmeters that are in the flow path and flowmeters that are branched from the pipe. Pressure meters or pressure gauges are the most common type of flow measuring devices in the industry.
Dubai calculation basis
The basis for calculating the flow rate in this type of flowmeters is based on measuring the fluid velocity and then generating a signal proportional to the fluid velocity.
Factors affecting the flow rate in the pipe are:
Fluid velocity, fluid friction in contact with the tube, viscosity and density of the fluid.
Types of flow meters
Rotameter flowmeter or variable level
The rotameter is a conical tube and a float. Due to its low cost, simplicity, low pressure drop, relatively wide range of use and linear output, it is widely used to measure the flow of gases and fluids.
Spring and piston flow meter
A piston flowmeter is an annular hole consisting of a piston and a conical funnel.
The piston is positioned on the base of the cone (in “no-flow mode”) by a calibrated spring.
Scales based on specific gravity are 0.84 for oil meters and 1.0 for water meters.
The simplicity of the design and the ease of receiving the electrical output signal from them have made them a cost-effective alternative to rotameter flowmeters for displaying and controlling current flow.
Gas mass flow meter
Thermal type flowmeters are very slightly dependent on density, pressure and viscosity.
These types of meters use a differential pressure converter, a temperature sensor or heat measuring element, and the principles of thermodynamic heat transfer to accurately calculate mass flow.
Many of these meters have a general and instantaneous analog output display.
These meters are commonly used to test for gas leaks and to measure low currents in millimeters per minute.
Ultrasonic flowmeter
Ultrasonic Doppler flowmeters are commonly used in conditions where the working conditions are dirty, such as sewage and other dirty fluids and slurries, which usually cause the failure of traditional meters.
The principle of operation of this flowmeter is based on the change of frequency (Doppler effect) of the ultrasonic signal reflected by floating materials and moving gas bubbles.
Turbine flow meter
The turbine flowmeter can calculate the flow rate with an accuracy of about 0.5%.
This type of flow meter is very accurate and can be used for clean liquids and viscous fluids (Viscous) up to 100 cm.
The distance between the location of the turbine flowmeter and the place where the fluid flow enters the straight pipe must be at least 10 times the diameter of the pipe.
The output of a turbine flowmeter is usually sinusoidal or square wave frequency, but signal enhancement systems can be installed for analog outputs and explosion-proof classifications.
The meter consists of a vane rotor that is mounted at a right angle and suspended on bearings in the fluid flow path.
Paddlewheel flowmeter
One of the most cost-effective flow meters used to measure water and fluids is the water vane flowmeter.
Many of them come with current connections or extensions.
Similar to turbine flowmeters, the distance between the installation site of this type of flowmeter in a straight pipe and the inlet of the flow should be at least 10 times the diameter of the pipe and from the outlet of the fluid should be at least 5 times the diameter of the pipe.
Positive displacement flow meter
These types of meters are used for water and are used when there is no direct pipeline and there is a possibility of turbulent currents for turbine flowmeters and vane sensor.
Positive displacement flowmeters are also used for viscous fluids.
Vortex flow meter
The main advantage of vortex flow meters is their low sensitivity to changes in flow status and less wear than turbine and orifice flowmeters.
They also have low initial installation and maintenance costs.
For these reasons, this type of flowmeter has become more popular among consumers. Vortex flowmeters require contact and flow engineering adaptation.