What is a flowmeter?
One of the most common tools for measuringFlowD / P cell is used in which the orifice plate is used.
The output of D / P cells is flow, but here all systems are linear, so they output to the extractor so that the root is taken and linear.
D / P cell (for flow measurement):
At the inlet of the D / P cell, an orifice plate (or venture tube, in cases where high precision is required or particles suspended in the liquid are high) is placed in the fluid path. Orifice plate A circular plate with a hole in the center (possibly in the lower half of the plate for high-viscosity liquids) that is placed perpendicular to the fluid for liquids and obliquely for gases. Be. By passing the fluid through this plate on both sides of it pressure difference Is created. The pressure on either side of the orifice is given to the DP Cell as LP and HP (low pressure and high pressure, respectively). This device converts the pressure difference to an absolute pressure and then to an air pressure of 3 to 15. An output of 3-15 psi is sent to the controller as a measurement signal. The command is sent from the controller to the control valve and causes it to open or close and adjust the fluid flow.
DP Cell of an air relay, a Nuzzle-Flapper, a capsule, a Force Bar that leverages between the capsule and the Nuzzle-Flapper and a Bellows asfeedbackIt is composed of two HP and LP inputs and one Air Supply input.
20 pound Supply air enters the relay and the relay output is routed to Nuzzle as well as sBellow.
HP and LP are applied to the sides of the diaphragm (or capsule). Aperture compression causes BarForce e to move, thus increasing the distance between the Flapper and the Nuzzle. On the other hand, the air that enters the bellows causes it to expand and the Flapper to approach the Nuzzle, thus preventing the Nuzzle-Flapper distance from increasing. In fact, with such a mechanism, these Bellows create a kind of balance between the pressure difference between HP and LP and the supply air, and play the role of a kind of feedback. The final output is the same as Nuzzle air after balancing.
Air relay
Relays are the main element in pneumatic devices that are responsible for producing air suitable for 3-15 psi.
Inlet air to the backDiaphragmConnected to the Valve. The reference air also puts pressure directly on the valve. The difference between these two pressures can open the Valve and thus remove part of the reference air from the relay, which enters the rest of the process as the output of the relay and part of the reference air is also Exhaust.
Measuring fluid levels
In industrial operations, it is often very important to know how the liquid level in the tanks. For this purpose, different methods are used in the refinery, the simplest of which is the use of Archimedes’ law in different methods of buoyancy, immersion or manual methods.
Since most of the liquids in the industry are in closed tanks, special methods must be used due to the impossibility of observing the liquid level. The most common method for this purpose is to use methods based on pressure difference:
D / P Cell is used for this purpose.
Other relatively new methods, such as capacitive or radar methods, are also used in certain cases.
D / P Cell (for level measurement)
In closed tanks (liquid with gas) for height measurement,LP pressure The highest point of the tank (gas pressure on the liquid) and HP is the lowest point pressure of the tank.
HP taping is usually taken from a height of one meter because the bottom of the tank is the place where the waste enters the tank with the fluid from the pipes.
In open tanks (usually liquids) LP is the same as atmospheric pressure and HP is the pressure at the lowest point of the tank and gives the pressure measured in relation to the height of the liquid in the tank.
The DP Cell capsule is available in the Range (Mid Range) 20-200, (Low Range) 0-20 (Range High), which represent the pressure difference tolerated byCapsuleare. LP and HP pressures may be around 6,000 psi, but what applies to the capsule is the difference between HP and LP.
Types of vortex flowmeters:
Vertex flowmeter
Universal measurement of the volume flow of gases, steam and liquids
– Measurement of flow in liquids, vapors and gases
– Temperature range of 200 to 400 degrees Celsius
– High resistance to vibration, heat shock, particles in the fluid and hammer impact of water
– Ability to compensate for temperature and pressure
Ability to measure flow in fluids Conductive And non-conductive such as distilled water
Ultrasonic flowmeter
Ability to measure flow in conductive and non-conductive fluids using sound waves
– Possibility of installation in fluid path (In Line) and indirectly (Clamp On)
– Temperature tolerance from minus 40 to positive 170 degrees Celsius
– Ability to install on pipes in different sizes
Thermal flowmeter
Ability to measure mass flow in gases using fluid heat transfer coefficient
– Possibility of installation in the path of various gaseous fluids and liquids inline or insertion on pipes and ducts ((duct
– Operation at 130oC temperature and maximum pressure 40bar
– Has an explosion-proof certificate and suitable for installation on the lines leading to the torch (flare)
Mass flowmeter
Mass flowmeter measures the mass of fluid independent of the physical properties of the fluid, such as viscosity and density.
And the parameters of mass, density and temperature are measured simultaneously in this device.
Mass flowmeters typically have two inner tubes that are possible in high viscosity fluids
There is also a choice of flowmeter with an internal tube.
Mass flowmeter features:
– Very high accuracy in measuring the flow of liquids and gases such as oil and fuels, oils and lubricants,
Liquefied gases, solvents, food and pharmaceutical fluids, compressed and compressed gases
– Has the standard of explosive environment ATEX, FM, CSA, TIIS, IECEx, NEPSI
– Has food and pharmaceutical / health industry standards 3A, FDA, EHEDG
– Ability to connect to HART, PROFIBUS DP / PA, FOUNDATION Feildbus, MODBUS monitoring systems
– Pressure tolerance up to 350bar
– Measurement of volumetric flow rate of fluids with conductivity μ 5 μS / cm
– High accuracy, reasonable price and the ability to select all properties of the flowmeter, such as its inner layer according to the characteristics of the fluid.
– Ability to work in different fluids of acids and bases, materials, water and wastewater, saline solutions, beverages and juices,
Dairy products, medicinal solutions and so on
– Pressure and temperature tolerance up to 180 oC, 40 bar
– Has global standards
– Has the standard of ATEX, IECEx, FM, CSA, NEPSI explosive environments