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.
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.
Orifice size corrected to reference temperature.
generally vena contracta is formed at distance of d/2 from orifice where d is diameter of orifice.
Because it relies on the back pressure through a known orifice which its differential pressure across the plate relates to flow.
measures the rate of fluid flow
As per R.W.Miller's hand book for flow measurement -- Bhadek
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.
a hammer
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.
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.
Corner tapping shall be used for installing orifices in pipeline size less than 2".