All kinds of instruments have their own characteristics, there is no perfect flow meter.

Flow meter (meter) use of the success of selection of instrument often plays a very important role, due to the complicated situation of measured object and is a great variety of instrument performance index, the making difficulty in the selection of instrument.

The purpose of the model selection is to choose the most suitable flowmeter instrument among many varieties.

(I) the steps of flow meter instrument selection are as follows:

1. According to the type of fluid and five factors, the primary available instrument types (several types should be available for selection);

2. Collect data and price information of primary election types for in-depth analysis and comparison;

3. Adopt the elimination method to gradually focus on one or two types, and make repeated comparative analysis on the five factors to finally determine the pre-selection target.

(2) general selection of flow meter (flow meter) :

It can be considered from five aspects: performance, fluid characteristics, installation conditions, environmental conditions and economic factors.

The detailed factors of the five aspects are as follows:

1. Instrument performance: accuracy, repeatability, linearity, range, flow range, signal output characteristics, response time, pressure loss, etc.;

2. Fluid characteristics: temperature, pressure, density, viscosity, chemical corrosion, abrasion, scaling, mixed phase, phase change, conductivity, sound velocity, thermal conductivity, specific heat capacity, etc.

3, installation conditions: pipeline arrangement direction, flow direction, testing a upstream and downstream straight pipe length, pipe diameter, space, power supply, grounding, auxiliary equipment maintenance (filters, venting device), installation, etc.;

4. Environmental conditions: ambient temperature, humidity, electromagnetic interference, safety, explosion protection, pipeline vibration, etc.

5. Economic factors: instrument purchase fee, installation fee, operation fee, inspection fee, maintenance fee, instrument service life, spare parts, etc.