Conditions that must be met when using a throttling flow meter

The throttling flow meter is a commonly used flow measurement instrument, which is widely used in many industries. There are certain conditions when we use the throttling flow meter. Today, the editor will mainly introduce to you the conditions that must be met when using the throttling flow meter. I hope it can help you.

The reason why the throttling flowmeter is so widely used is mainly because it has the following two very prominent advantages: the throttling flowmeter is a typical differential pressure flowmeter. It is the most commonly used flow meter in industrial production to measure the flow of gas, liquid and steam. According to survey statistics, about (70-80)% of the flowmeters used in industrial production systems such as steel mills and refineries are throttling flowmeters. In the entire industrial production field, throttling flowmeters also account for more than half of the total number of flow meters.

①Simple structure, easy installation, reliable operation, low cost, and certain accuracy. It can meet the needs of engineering measurement.

② It has a long history of use, rich and reliable experimental data, and the design and processing have been standardized. As long as the throttling flowmeter is designed and processed according to the standard, it does not need to be calibrated, and the flow can be measured within a known uncertainty range.

Measurement.

When using a standard throttling device, the properties and state of the fluid must meet the following conditions:

①The fluid must fill the pipe and throttling device and flow continuously through the pipe.

② The fluid must be a Newtonian fluid, that is, it is physically and thermodynamically uniform and single-phase, or can be considered to be single-phase, including mixed gases, solutions and colloids with dispersed particles smaller than 0.1 m. A gas with no more than 2% (mass composition) of uniformly dispersed solid particles, or a liquid with no more than 5% (volume composition) of uniformly dispersed bubbles can also be considered a single-phase fluid. However, its density should be the average density.

③ The fluid does not intersect when it flows through the throttling device.

④The fluid flow rate does not change with time or changes very slowly.

⑤ Before the fluid flows through the throttling device, the flow is an irrotational flow parallel to the axis of the pipe.