What conditions must the differential pressure flowmeter meet for the nature and state of the fluid?
A differential pressure flowmeter using a throttling device is usually composed of a throttling device that converts fluid flow into a differential pressure signal and a differential pressure gauge that measures differential pressure and displays the flow rate. The throttling device installed in the flow pipeline is also called " "Primary device", which includes throttling parts, pressure taking devices and front and rear straight pipe sections. The display device is also called "secondary device", which includes instruments such as differential pressure transmitters and flow totalizers.
When using standard throttling devices, the following conditions must be met for the nature and state of the fluid:
1. The fluid must fill the pipe and the throttling device, and flow through the pipe continuously.
2. The fluid must be a Newtonian fluid, that is, physically and thermodynamically homogeneous, single-phase, or can be considered as a single-phase, including mixed gases, solutions, and colloids with dispersed particles smaller than 0.1 microns. Uniformly dispersed solid particles not greater than 2% (mass component), or uniformly dispersed air bubbles not greater than 5% (volume component) in the liquid can also be considered as a single-phase fluid, but the average density should be taken.
3. There is no intersection when the fluid flows through the throttling member.
4. Fluid flow does not change or changes very slowly over time.
5. Before the fluid flows through the throttling piece, the stream is a non-swirl flow parallel to the axis of the pipe.
