orifice

This is not a homework cheating site, ok? Just some thoughts though...

Too vague... an orifice as you wrote can be used to fill a container, to empty it, to look through a wall, to guide a cable, etc. In some cases, it may even be used for flow measurements! Amazing!

A restriction orifice can be inserted to some opening to avoid filling, to avoid emptying, to avoid dropping bigger things in some opening, to limit the flow of a fluid through sme passage, to allow a pet to cross a door while keeping outside the friends of the other's property.

In other words... please, reformulate the question.

sachin05.ghadi

Because you gave us only limited information we are left to guess what you are talking about. I think you are talking about Process Plant Piping design and the use and purpose of the different types of the object called an "Orifice".

First: the definition of the word "orifice": ": an opening (as a vent, mouth, or hole) through which something may pass"

Second: The term "Orifice" is used in two ways in the Piping profession. There is the "Orifice Meter" and the "Restriction Orifice" both of which I feel you are asking about.

The "Orifice Meter" is a method of measuring the floe in a pipe line. It is made up of the following elements:

• an upstream run (length) of pipe. This run of pipe needs to be select pipe with a very smooth bore and 10 to 20 diameters in length.
• a downstream run of pipe. This run of pipe needs to be select pipe with a very smooth bore and a minimum of 5 diameters in length.
• a pair of "Orifice Flanges". These flanges mated face to face and are specially made with "Flange Taps". In the space between these flanges will be a gasket, the orifice plate and a second gasket.
• the "Orifice Plate". The Orifice Plate is normally flat and tends to block the flow in the line except for the "orifice" (or hole) normally in the center of the plate. The "Hole" on the orifice plate is not always round and is not always in the center. The hole will sometimes have square profile, a tapered profile or a rounded profile.
• the "Flange Taps". The flange taps (two each in the upstream and downstream flange) are holes drilled 180 degrees apart through the flange between the bolts from the outside diameter of the flange through to the inside diameter of the flange. External piping, valves and instruments are connected to these taps to take continuous readings. This all becomes part of a more extensive and complex "Control Loop".

The purpose of an Orifice Meter is to measure the flow in the specific pipe. It is done (both in liquid and cases) by reading the pressure differential (upstream and downstream) of the plate. This "Flow" rate can then be used to do other "work" in a control loop of a process system.

The "Restriction Orifice" is a method to "govern the amount of flow of a liquid or gas in a pipe. It is composed of some kind of a blockage or plug in the line with a pre-determined hole size drilled in it. There is no specific upstream or downstream runs involved. It is just a flow restriction. Unless it is removed and replaced with another plug with a different hole it is not adjustable. If you must have an adjustable feature to the restriction then you need to use a Globe Valve or a Needle Valve.