Orifice Meter
An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a '). Description An orifice plate is a thin plate with a hole in it, which is usually placed in a pipe. When a fluid (whether liquid or gaseous) passes through the orifice, its pressure builds up slightly upstream of the orifice but as the fluid is forced to converge to pass through the hole, the velocity increases and the fluid pressure decreases. A little downstream of the orifice the flow reaches its point of maximum convergence, the ''vena contracta'' (see drawing to the right) where the velocity reaches its maximum and the pressure reaches its minimum. Beyond that, the flow expands, the velocity falls and the pressure increases. By measuring the difference in fluid pressure across tappings upstream and downstream of the plate, the flow rate can be obtained from Bernoulli's equation using coefficients established from extensive r ...
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Orifice
An orifice is any opening, mouth, hole or vent, as in a pipe, a plate, or a body * Body orifice, any opening in the body of a human or animal *Orifice plate, a restriction used to measure flow or to control pressure or flow, sometimes given specialised names: ** Calibrated orifice, used to control pressure or flow ** Restrictive flow orifice, used to control flow ** Miss Shilling's orifice, used to control flow in the engines of early Spitfire and Hurricane fighter aeroplanes * Back Orifice, a controversial computer program designed for remote system administration See also * Choked flow * Needle valve * Nozzle * Venturi effect * Flow measurement Flow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways. The common types of flowmeters with industrial applications are listed below: * a) Obstruction type (differential pressure or variable area ...