A grated plate, for example, can introduce such a profile.ĭifferential-pressure flowmeter piping requirementsĭP flowmeters measure the drop in pressure across a flow element in the piping, such as an orifice plate. Flow conditioners can reduce swirl and also mimic a fully developed profile. These solutions reduce swirl, but not flow profile variations some may even introduce a distorted profile. Flow-straightening devices include tube bundles, perforated plates, and internal tabs. Long straight-pipe lengths can be avoided through the use of flow-straightening devices and flow conditioners. Obstructions upstream and near the flowmeter can cause errors ranging beyond 50 percent.įlowmeter manufacturers will recommend various lengths of straight pipe upstream and downstream of the flowmeter to attain a fully developed desirable flow profile. Swirl is far more difficult to correct than flow-profile distortion. Swirl occurs when the fluid moves through piping bends in different planes. Flow-profile distortion and swirl - the two most prominent types of fluid disturbance that affect a meter’s flow coefficients - are typically the products of improper piping configuration.įluid profile distortion occurs when an obstruction - such as a partially open valve or a poorly mounted flange gasket - partially blocks the pipe.
Improper flowmeter installation can disturb this profile and degrade measurement accuracy. When a fluid flowing through a pipe assumes a desirable flow profile, it moves uniformly with the greatest velocities near the center of the pipe.
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