Main process parameters and flow measurement of flow meters

Main technical parameters of flow meter

(1) Flow range The flow range refers to the range of the maximum and minimum flow rates that the flow meter can measure.

(2) Range and range ratio The difference between the maximum flow rate and the minimum flow rate within the flow range is called the range of the flow meter. The ratio of the maximum flow rate to the minimum flow rate is called the range ratio, also known as the range of the flow meter.

(3) Allowable error and accuracy level The maximum error allowed by the flow meter under the specified normal working conditions is called the allowable error of the flow meter, which is generally expressed by the maximum relative error and the reference error. The accuracy level of the flow meter is divided according to the size of the allowable error. The accuracy levels are: 0.02, 0.05, 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, etc.

Flow measurement method

Flow measurement methods can be roughly classified into the following categories:

(1) The differential pressure flow measurement method uses the Bernoulli equation principle to reflect the flow rate by measuring the fluid differential pressure signal;

(2) Velocity flow measurement method that directly measures the fluid velocity to obtain the flow rate;

(3) Volumetric measurement using a standard small volume to continuously measure flow;

(4) Mass flow measurement method for the purpose of measuring fluid mass flow rate.

Pressure loss

The size of pressure loss is an important technical indicator for flow meter selection. The smaller the pressure loss, the less fluid energy consumption, the smaller the power requirement for transporting the fluid, and the lower the measurement cost. On the contrary, the energy consumption is large and the economic benefits are correspondingly reduced. Therefore, it is hoped that the pressure loss of the flow meter is as small as possible.