Instruments that measure fluid flow are collectively referred to as flow meters or flow meters. The flowmeter is one of the important instruments in industrial measurement. With the development of industrial production, the accuracy and range of flow measurement requirements are getting higher and higher, and the flow measurement technology is changing with each passing day. Various types of flow meters have been introduced to suit various applications. More than 100 flow meters have been put into use. From different perspectives, flow meters have different classification methods. There are two commonly used classification methods. One is to classify according to the measurement principle adopted by the flowmeter: the second is to classify according to the structural principle of the flowmeter.
Sort by measurement principle
a. Mechanical principle:
Instruments belonging to such principles have differential pressure type, rotor type using Bernoulli's theorem;
Impulse type using the momentum theorem, movable tube type;
Direct mass equation using Newton's second law;
a target using the principle of fluid momentum;
Turbine using the angular momentum theorem;
Vortex type using vortex principle of fluid oscillation;
Use the total static pressure difference of the pitot tube type as well as volumetric and sputum, trough and so on.
b. Electrical principle:
Electromagnetic,
Differential capacitor type,
Inductive,
Strain resistance type, etc.
c. Acoustic principle:
Ultrasonic.
d. Thermal principles:
Thermal type,
Direct calorimetry,
Indirect calorimetry and so on.
Electrode material
Corrosion resistance and wear resistance
Stainless steel: 0Crl8Nil2M02Ti is used for industrial water, domestic water, sewage and other weakly corrosive media. It is suitable for petroleum, chemical, steel and other industrial sectors as well as municipal, environmental protection and other fields.
Hastelloy B: has good corrosion resistance to hydrochloric acid at all concentrations below the boiling point, and is also resistant to corrosion by non-chlorinated acids, bases, non-oxidizing salts such as sulfuric acid, phosphoric acid, hydrofluoric acid, and organic acids.
Hastelloy C: resistant to non-oxidizing acids, such as nitric acid, mixed acid, or corrosion of mixed media of chromic acid and sulfuric acid, and also resistant to oxidizing salts such as Fe, ", Cu" or other oxidants, such as Corrosion of hypochlorite solution and seawater above normal temperature
Titanium: It is resistant to seawater, various chlorides and hypochlorites, oxidizing acids (including fuming sulfuric acid), organic acids and alkalis. It is not resistant to the corrosion of relatively pure reducing acids (such as sulfuric acid or hydrochloric acid), but if the acid contains an oxidizing agent (such as nitric acid, Fc++, Cu++), the corrosion is greatly reduced.
钽: Excellent corrosion resistance and glass are very similar. In addition to hydrofluoric acid, fuming sulfuric acid, alkali, it is almost resistant to the corrosion of chemical media (including boiling point of hydrochloric acid, nitric acid and sulfuric acid below 50 ° C). Antimony in alkali; corrosion resistant.
Platinum/titanium alloy
Almost resistant - cut chemical media, but not for aqua regia and ammonium salts.
Stainless steel coated tungsten carbide
For non-corrosive, strong abrasive media.
Note: Due to the wide variety of media, its corrosiveness is affected by complex factors such as temperature, concentration and flow rate, so this table is for reference only. The user should make his own choice according to the actual situation. If necessary, the corrosion resistance test of the material to be selected, such as the coupon test.
Gas turbine flowmeter and screwing vortex flowmeter measurement difference
Keywords: gas turbine flowmeter, Tianxin gas turbine flowmeter, gas gas turbine flowmeter
The gas turbine flowmeter has good repeatability and is the preferred flow meter for trade settlement. The gas swirling vortex flowmeter is generally repeatable.
The gas turbine flowmeter can obtain very high frequency signals with strong signal resolution. The frequency of the gas swirling vortex flowmeter is very low, and the smaller the diameter, the lower the signal resolution. The measurement error is to be measured.
The gas turbine flowmeter has a wide range, generally 40:1~20:1, and has a wide measuring range, which can be suitable for occasions with large flow changes. When natural gas is delivered, the flow changes are generally large and, therefore, are particularly suitable for natural gas measurements. The latter range is medium, generally 15:1 to 10:1, and the measurement range is slightly narrower. When measuring gas, it is more suitable for occasions where the flow rate does not change much.
In terms of seismic performance, gas turbine flowmeters have better resistance to pipeline vibration. The gas swirling vortex flowmeter is susceptible to pipeline vibration and should be taken care of when using it.