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Because it relies on the back pressure through a known orifice which its differential pressure across the plate relates to flow.
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What is meant by the phrase Orifice Plate?
The phrase Orifice Plate is actually a device that measures either volume or mass flow rate. An Orifice Plate is a thin plate like device that has a hole in the middle.
What is the order of efficiency of venturi meter orifice meter and rotoameter?
The orifice plate can easily be changed to accomodate widely different flow rates, whereas the throat diameter of a venturi is fixed, so that its range of flow rates is circumscribed by the practical limits of Dp.The orifice meter has a large permanent loss of pressure because of the presence of eddies on the downstream side of the orifice-plate; the shape of the venturi meter prevents the formation OS these eddies and greatly reduces the permanent loss.The orifice is cheap and easy to install. The venturi meter is expensive, as it must be carefully proportioned and fabricated. A home made orifice is often entirely satisfactory, whereas a venturi meter is practically always purchased from an instrument dealer.On the other hand, the head lost in the orifice for the same conditions as in the venturi is many times greater. The power lost is proportionally greater, and, when an orifice is inserted in a line carrying fluid continuously over long periods of time, the cost of the power may be out of all proportion to the saving in first cost. Orifices are therefore best used for testing purposes or other cases where the power lost is not a factor, as in steam lines.However, in spite of considerations of power loss, orifices are widely used, partly because of their greater flexibility, because installing a new orifice plate with a different opening is a simpler matter. The venturi meter can not be so altered. Venturi meters are used only for permanent installations.It should be noted that for a given pipe diameter and a given diameter of orifice opening or venturi throat, the reading of the venturi meter for a given velocity is to the reading of the orifice as (0.61/0.98)2, or 1:2.58.(i.e. orifice meter will show higher manometer reading for a given velocity than venturi meter).
What is the purpose of the vent and bleed hole in a orifice plate?
Bleed or Weep Holes are located at the elevational top or bottom of the Orifice Plate. The Weep Hole is tangent to a circle equal to 98% of the line I.D. DRAIN HOLES are located at the bottom of the Orifice Plate to prevent liquids in a gas or condensate in a steam flow from damming up behind the Orifice Plate. VENT HOLES are located at the top of the Orifice Plate to allow gases in a liquid flow to vent pass the Orifice Plate.
What is the priciple of orifice flow meter?
An orifice flow meter is one of the simplest forms of flow meters. It is just a flat piece of metal installed in a pipe between flanges with a specific sized hole bored in the middle used to create pressure that can be detected by pressure taps on either side of the plate.
What does dr equals mean on a metal orifice plate?
Orifice size corrected to reference temperature.
At what distance from orifice plate vena contracta formed Can it be calculated?
generally vena contracta is formed at distance of d/2 from orifice where d is diameter of orifice.
What is the Application of orifice plate?
measures the rate of fluid flow
What standard is used for manufacturing and sizing the restriction Orifice plate and integral orifice?
As per R.W.Miller's hand book for flow measurement -- Bhadek
Difference between an orifice plate and a restriction orifice?
An orifice plate is a plat eused to measure flow. Pressure sensors are placed upstream and downstream of the the plate and hepressure differential is used with Bernoullis Equation t compute flow (including some experimental factors). A retriction plate is similar to an orifice plate but is much thicker. It is used to drop pressure upstream of a system. The convergence, throttlnig through thick section and divergece works the fluid and reduces total energy (transformed in firction, heat etc). This leads to an overall pressure reduction.
How do you remove tightly fitted steel plate in the orifice of steel sink?
a hammer
What is the difference between Restriction Orifice and Flow orifice or please explain the symbols RO Restriction orifice and FO Flow Orifice?
A restriction orifice (RO) is used to limit the flow through the pipe to a set flow by choking the flow at its sonic velocity. A flow orifice (FO) is usually used to determine the flow through the pipe from the pressure drop over the plate. There a normally two pressure taps (one on each side of the plate) and a pressure transmitter which determines the pressure drop over the plate. A formula is then used to convert this pressure drop to a flowrate for the specific fluid passing through the orifice. A FO usually has a temperature element to determine the gas temperature for use is the formula.
How does a restriction orifice in a pipe work?
the orifice plate creates a restriction in the pipeline which creates a pressure drop across the plate. commonly found in high pressure relief systems or drain points (as this would usually be a HP/LP interface) and can also be used to measure flow, by measuring the pressure drop across the plate.
