The differential pressure flowmeter using a throttling device is usually composed of a throttling device that can convert the fluid flow into a differential pressure signal, and a differential pressure gauge that measures the differential pressure and displays the flow rate. The throttling device installed in the circulation pipeline is also called a “primary device”, which includes a throttling piece, a pressure taking device, and front and rear straight pipe sections. The display device is also called the “secondary device”, which includes instruments such as differential pressure transmitters and flow totalizers.When using a standard throttling device, the following conditions must be met for the nature and state of the fluid:1. The fluid must fill the pipe and throttling device, and flow through the pipe continuously.2. The fluid must be a Newtonian fluid, that is, physically and thermodynamically uniform, single-phase, or can be considered single-phase, including mixed gases, solutions and colloids with dispersible particles smaller than 0.1 microns, and no larger than 2% (mass component) uniformly dispersed solid particles, or liquids with no more than 5% (volume component) uniformly dispersed bubbles, can also be considered as a single-phase fluid, but its density should be averaged.3. When the fluid flows through the throttle, no intersection occurs.4. The fluid flow rate does not change over time or changes very slowly.5. Before the fluid flows through the throttle, the stream is a non-swirl flow parallel to the axis of the pipe.The flowmeter with standard throttling device is not suitable for flow measurement of dynamic flow and critical flow.
Post time: 21-09-21