A
calibrated orifice is a restriction that is deliberately placed into a system of
pipePipeline transport is the transportation of goods through a pipe. Most commonly, liquids and gases are sent, but pneumatic tubes that transport solid capsules using compressed air are also used....
s to set the flow rate through the system. The
orificeAn orifice is any opening, mouth, hole or vent, as of a pipe, plate, or a body.* Body orifice* Orifice plate* Calibrated orifice* Nozzle* Back Orifice-See also:* Choked flow* Needle valve* Venturi effect* Flow measurement...
may be designed to produce proportional flow (as in the jet in a
carburetorA carburetor , carburettor, or carburetter is a device that blends air and fuel for an internal combustion engine. It is sometimes shortened to carb in North America and the United Kingdom....
), or
choked flowChoked flow is a compressible flow effect. The parameter that becomes "choked" or "limited" is the velocity or the mass flow rate.Choked flow is a fluid dynamic condition associated with the Venturi effect...
(as in a filtering bypass in a closed industrial cooling system, which might be designed to pass a particular flow rate through a filter assembly to maintain cleanliness of a closed-loop fluid system).
Many pressure gauges also use an
orificeAn orifice is any opening, mouth, hole or vent, as of a pipe, plate, or a body.* Body orifice* Orifice plate* Calibrated orifice* Nozzle* Back Orifice-See also:* Choked flow* Needle valve* Venturi effect* Flow measurement...
(also called a restrictor) to limit the flow into a gauge. Since the pressure is even throughout the system, allowing only a small portion of the flow into the actual gauge allows it to be in parallel with the pressure circuit and still measure accurately. It also prevents or minimizes damage to the gauge during pressure surges at start-up, or due to any spikes in the system pressure.