Orifice Flowmeter

- Nov 24, 2017 -

Orifice flow meter applications: A, the fluid must be full tube continuous operation, B, the fluid must be Newtonian fluid, physically and thermodynamically uniform single-phase, C, fluid flow through the throttling device D, the fluid flow basically does not change over time, does not apply to pulsatile flow and critical flow conditions, E, the fluid flow through the throttling device must be parallel to the axis and no swirling flow, F, Fluid flow conditions should be turbulent, Reynolds number in a certain range and no vortex.

Orifice throttling device Flowmeter composition: including orifice plate, pressure flange or ring room, differential pressure transmitter three parts, including orifice plate used to produce differential pressure, pressure flange or ring chamber for Remove the orifice before and after the fluid pressure, differential pressure transmitter for measuring the pressure before and after the orifice to measure the flow of fluid through the orifice of the purpose.

Orifice throttling device flowmeter installation requirements: A, throttling installation requirements are 10 times before the pipe diameter of 5 times the straight pipe requirements; B, throttling pieces and clamping flange front end should be perpendicular to the pipe axis , Throttle opening, clamping flange should be concentric with the pipeline; C, the seal throttling piece gasket shall not protrude into the pipe wall, and gasket thickness should not exceed the specified value; D, the newly installed piping system must After the purge is qualified to install the orifice plate, the acute angle of the orifice plate should meet the flow direction; E, when measuring the gas, the pressure port should be within 45 degrees of the vertical angle between the upper part of the pipe and the pipe; The pressure inlet should be within 45 degrees of the angle between the upper part of the pipe and the horizontal centerline of the pipe. When measuring liquid, the pressure inlet should be within 45 degrees of the horizontal center line of the pipe. F, the level of measurement gas (or liquid) pressure guide tube should exclude condensate liquid (or gas) piping slope 1: 10 ~ 1: 100.

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Orifice throttling device flow meter and the use of discontinued methods: A, the flowmeter before the vote, it should be installed to check whether the requirements of the pipeline is clean, the pressure test has been completed; B, after the flow to ensure that traffic Meter in its effective measurement range smooth operation; C, flowmeter investment steps: check the secondary valve and the drain valve should be closed, the balance valve should be opened → slightly open a root valve, check the pressure piping system for leaks, do not leak Turn on the blow-off valve and then close the blow-off valve → unscrew the plug of the positive and negative pressure chamber of the differential pressure transmitter, remove the air → open the transmitter positive-pressure valve, close the balance valve, and turn on the transmitter Negative pressure valve, start differential pressure transmitter; D, instrumentation three valve group operating principles: 1, can not allow the conductivity of condensate or isolation fluid loss; 2, the transmitter can not be measured diaphragm pressure or heat ; Three valve group to start the order: open positive pressure valve → off balance valve → open negative pressure valve; E, flowmeter disable step: turn off the transmitter negative pressure valve, open the balance valve, turn off the transmitter positive pressure Valve → close the secondary valve → open the drain valve to drain Rear

Close the drain valve; the three-valve group to disable the order: Off negative pressure valve → open balance valve → off positive pressure valve.


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