The lining material should be selected according to the corrosiveness, wear and temperature of the tested medium:
First, natural rubber (soft rubber)
1, better elasticity, wear resistance and tearing force
2, resistant to general weak acid, weak alkali corrosion
3. Water and sewage
Second, acid-resistant rubber (hard rubber)
It can withstand the corrosion of hydrochloric acid, acetic acid, oxalic acid, ammonia water, phosphoric acid and 50% sulfuric acid, sodium hydroxide and potassium hydroxide at normal temperature, but it is not resistant to corrosion by strong oxidants.
It can measure general acid, alkali and salt solutions.
Third, neoprene (Neoprene)
1, excellent elasticity, high tearing force, good wear resistance
2, resistant to general low concentration of acid and alkali, salt solution corrosion, but not resistant to oxidation of the medium, and temperature requirements <80 ° C;
It can measure water, sewage, mud and pulp.
Fourth, Polyurethane (Polyurethane)
1, excellent wear resistance
2, poor acid and alkali resistance, temperature requirements <40 ° C
Measure medium-strongly worn coal slurry, mud and slurry
Five, polytetrafluoroethylene (PTFE)
1. Boiling hydrochloric acid, sulfuric acid, nitric acid, aqua regia, concentrated alkali and various organic solvents
2, good wear resistance, poor bonding performance, temperature requirements -80 ~ +180 ° C;
Measuring concentration, concentrated alkali strong corrosive solution and sanitary medium
Vortex flowmeter verification detection method
Standard table method
The vortex flowmeter is used as a standard device in series with the flowmeter to be inspected, and can be verified by static method or dynamic method. By comparing the readings of the two flow meters, the error of the vortex flowmeter to be tested is obtained.
Standard table flow meter standard device features:
1. Standard table method is suitable for measuring various fluids (including liquids and gases), and also for liquids of various viscosities.
2. The indication value is checked. The flow meter used as the standard meter is installed in series with the flowmeter to be tested in the same closed pipeline system. Generally, there is no time measurement error.
3. As a standard table, the vortex flowmeter can be the same as or different from the flowmeter to be tested.
4. When the flow meter is verified by the standard meter method, the airflow or liquid flow can be not cut off, so it is suitable for online verification, and is also suitable for the measurement standard for the closed pipeline. 5, the standard table method is easy to achieve automation, sealed and safe, does not pollute the environment.
6. Small size, light weight, simple device structure, convenient operation, easy transportation and installation, and low cost.
7. Standard meter flowmeters have low accuracy and poor stability, and often need to be compared regularly or irregularly to monitor their metering performance. The standard table has a shorter verification period.
Mass flow meter
Since the volume of the fluid is affected by parameters such as temperature and pressure, it is necessary to give the parameters of the medium when the flow rate is expressed by the volume flow. In the case of changing media parameters, it is often difficult to achieve this requirement, resulting in distortion of the meter display value. Therefore, mass flow meters have been widely used and valued. Mass flow meters are available in both direct and indirect versions. Direct mass flow meters are measured using principles directly related to mass flow. Currently used mass flow meters such as calorimetric, angular momentum, vibratory gyro, Magnus effect and Coriolis force. The indirect mass flow meter is obtained by directly multiplying the density meter by the volumetric flow rate to obtain the mass flow rate.
In modern industrial production, the operating parameters such as temperature and pressure of the flowing working fluid are continuously improved. In the case of high temperature and high pressure, due to the material and structure, the application of the direct mass flowmeter is difficult, and the indirect quality is encountered. Flowmeters are often not suitable for practical applications because they are limited by the range of humidity and pressure. Therefore, a temperature-pressure-compensated mass flowmeter is widely used in industrial production. It can be regarded as an indirect mass flow meter. Instead of using a density meter, it uses the relationship between temperature, pressure and density. It uses a temperature and pressure signal to calculate the density signal by function, and multiplies it by the volume flow. Mass Flow. At present, temperature and pressure-compensated mass flowmeters have been put into practical use. However, when the measured medium parameters vary widely or rapidly, it will be difficult or impossible to correctly compensate, so further study the mass flow rate applicable in actual production. Meters and densitometers are still a topic.
Chen's above-mentioned common structural principle of flowmeters is much better than various types of flowmeters, such as various helium flowmeters and trough flowmeters for open channel flow measurement; flowmeters suitable for large-caliber flow measurement; measuring laminar flow Laminar flowmeter; related flowmeter for two-phase flow measurement; and laser method, nuclear magnetic resonance flowmeter and various tracer methods, dilution method flow measurement, etc. With the development of technology and practical application needs, the new flowmeter will continue to emerge more types of flowmeters.