Orifis Plate
The orifice plate is the most common type of limiter that is used extensively in measuring flow. The orifice plate is actually a thin, round metal plate with a hole in the center. The orifice plate has a They are tabs on which the specifications of the orifice plate are engraved.
The upstream side of the orifice plate usually has a sharp edge. When the orifice is installed in the flow line. It is usually tightened between a flange. Pressure is a function of flow rate.
By placing the orifice in the tube path, the pressure is slightly increased due to the interaction of the static pressure upstream of the orifice. And the flow rate reaches its maximum.
Farther away from this point, the static pressure begins to recycle and slows down the flow. However, with an Orifice, the downstream static pressure is always significantly lower than the upstream pressure. Orifice plate converts the amount of pressure energy into sound and heat
The flange pulse is the most widely used method of sampling pressure on both sides of the orifice. These pulses are actually holes that are up to 1 inch upstream.
And are located 1 inch below the surface of the orifice plate. When a pressure transmitter is installed and used to measure flow, it can be called a flow transmitter.
The static pressure inside a tube containing a fluid may be several times greater than the differential pressure created by the orifice plate.
When using a low-pressure differential capsule, a three-valve or one-inch volumetric semen is used to protect the DP capsule from overpressure.
Corner tap
Corner taps are installed just above the upper and lower levels of the orifice.
vena contracta
One of the pulses of the vena contracta, located at the top, is located at a distance of one tube in diameter from the surface of the orifice plate, while
The downstream pulses should be at the point where the lowest pressure is, which is usually at a distance of half the diameter of the pipe to the surface of the orifice. .5 times the diameter
The inside of the tube is located on the upper side of the hand and the other pulse is created at a distance of 8 times the inner diameter of the tube and on the downstream side.
When the orifice plate is used with one of the standard pressure pulses, the calibration is not in place of the Nielsen flow transmitter.
Experience has shown that the use of tables and graphs facilitates calibration when the ratio and type of pressure pulse used have been determined.
Advantages and disadvantages of Orifis Plate
The advantages of Oriflate plates are:
* Create a large differential pressure.
* Comprehensive information is available
* Low purchase and installation costs.
* It is easy to replace.
Disadvantages of Orifis Plate are:
* High permanent pressure drop, which means high pumping cost.
Oriflate Plate can not be used for dirty fluids of two gutters and water vapor because these materials cause gradual wear and tear and change the differential pressure produced by Orifis.