Selection principle of flowmeter in industrial production 3

3. Turbine flowmeter

For the material

Used for measuring volume flow and accumulation of low viscosity, non corrosive, clean liquid in closed pipe.It can be widely used in petroleum, chemical industry, metallurgy, organic liquid, inorganic liquid, liquefied gas, city gas pipe network, pharmacy, food, paper and other industries.Water, oil, diesel and other liquids.

The principle of structure

The liquid turbine flowmeter consists of a turbine and an external pulse-detector. The liquid flows into the turbine, causing the rotor to rotate. The specific inner diameter makes the rotor speed directly proportional to the flow rate.

Measuring characteristics

Strong anti-impurities, tangential impeller in the rotation of fluid can be released at any time suspended debris, so that it is not wound on the blades of tangential impeller.

Strong resistance to electromagnetic interference and vibration.

 

Disadvantages:

(1) the calibration characteristics cannot be maintained for a long time;

(2) the physical properties of the fluid have a great influence on the flow characteristics.

   

Matters needing attention

1. Flange connection, thread connection and clamping are adopted for instrument installation.

2. During installation, the direction of liquid flow shall be the same as the arrow indicating the direction of flow on the sensor housing, and the upstream straight pipe segment shall be ≥6DS, and the downstream straight pipe segment shall be ≥5DS (DS is the measured inner diameter of the pipeline under test).

   

3. In order not to affect the normal liquid transportation during maintenance, bypass pipes should be installed outside the straight pipe sections at both ends of the sensor.

4. Electromagnetic flowmeter

For the material

Can accurately measure all kinds of acid, alkali, salt solution, raw water, cooling water, sewage, slurry electromagnetic flowmeter, pulp, mud, slurry, pulp, syrup, coal water slurry, corn starch, fiber pulp, syrup, milk of lime, hydrogen peroxide, and beer wort, black liquor, green liquid solution and various beverages conductive volume of fluid and solid liquid two phase flow.

The principle of structure

Electromagnetic flowmeter consists of sensor and converter.Based on Faraday's law of electromagnetic induction, it is used to measure the volume flow rate of conductive liquid with conductivity greater than 5 S/cm. It is an inductive instrument for measuring the volume flow rate of conductive medium.In addition to measuring the volume flow rate of the general conductive liquid, it can also be used to measure the volume flow rate of the strong corrosive liquid such as strong acid and alkali and the uniform liquid and solid two-phase suspension liquid such as mud, pulp and pulp.

Measuring characteristics

Measurable fluid: the working principle of electromagnetic flowmeter, electromagnetic flowmeter can choose to measure flow of fluid must be conductive, strictly speaking, in addition to the high temperature fluid, as long as any fluid conductivity is greater than 5 mu/cm chooses the corresponding electromagnetic flowmeter to measure flow, so there is no conductive gas, steam, oils, acetone and other material can't choose electromagnetic flowmeter to measure flow rate.

Determination of sensor caliber: the flow rate of the flowmeter should be within the range of 0.3-15m/s. At this point, the diameter of the flowmeter can be chosen to be the same as the pipe diameter of the user.When the service flow rate is lower than 0.3m/s, it is better to increase the flow rate locally at the instrument part.

Matters needing attention

According to the characteristics of one type and separate type electromagnetic flowmeter, the suitable type is selected.One type electromagnetic flowmeter is easy to install, medium accuracy, not suitable for installation below the ground, in case the converter is flooded.Separate electromagnetic flowmeter, high accuracy, converter and sensor remote installation, more suitable for the site environment is poor (such as harmful, toxic, easy to be submerged by water and other places), but the installation, line application is more strict, otherwise easy to introduce interference signals.