Vortex Flowmeter

• The structure is simple and firm, no moving parts, long service life, small pressure loss, low operating cost.

• New structural design of mechanical vibration resistance, shock resistance and dirt resistance is adopted.

• It achieve high exchangeability and versatility from the detection probe to the transport discharge path.

• The circuit adopts surface mounting process, with compact structure and high reliability.

• Set the menu according to the general operation principle, and use Chinese characters to prompt, clear and intuitive, simple to operate.

• Within a certain range of Reynolds number, the output signal is not affected by the physical properties of the changes and components of the measured medium, and the instrument coefficient is only related to the shape and size of the vortex body, so it is generally not

necessary to reciliate the instrument coefficient after replacing the accessories.

• The 12864 full dot matrix LCD display with fine low power consumption displays the

instantaneous flow and cumulative flow, and compensates the measured temperature and pressure, and the data is rich and intuitive.

• It has the multipoint linear correction function and greatly improves the measurement

accuracy. After using the high-speed algorithm of single pulse and pulse by pulse

measurement, the compression or broadening calculation is only delayed one by one time, to achieve complete real-time linear compensation, this performance reaches the world's leading level.

• The differential pressure compensation vortex street mass flowmeter can directly measure the mass flow rate, which is not affected by the medium component or the dry degree

change,and the measurement accuracy is higher.

• The temperature and pressure compensation built-in or external sensor automatically

corrects temperature and pressure, directly converting the working condition flow into mass flow or volume flow under standard state. The measurement is simple and accurate, and 12 compensation algorithms can meet almost meet all flow compensation requirements.

Note:

1. The above parameters are only applicable to the vortex street flow meter with the following pressure specification of 1.6MPa.

2. The length of the instrument is standard size, and the length of the integrated pressure compensation instrument is increased by 50mm.

3. Flange connected vortex street flowmeter is not equipped with pipe flange and bolts when leaving the factory, and users need to buy separately. The standard of connecting flange is GB / T9119-2000 flat welded steel pipe flange.

Note:

1. The above parameters are only applicable to the pressure meter below 2.5MPa.

2. The installation flange is a special flange, which has been equipped when leaving the factory. The installation of flange is the enterprise standard and is recommended to use.

Explain:

1. The above dimensions are only for reference in the design and selection, and the actual size shall be subject to the factory or order confirmation.

2. The diameter of common seamless steel pipe is the diameter of metric steel pipe. If the British steel pipe is used, it should be indicated when ordering.

3. Pipe welding type, thread connection type, clamp connection type, fixed insertion type, ball valve insertion type structure appearance size, as well as high temperature type, ultra-low

temperature type shape size shall be subject to the delivery or order confirmation.

4. Flowmeter installation flange adopts enterprise standard or national standard GB/T9119-2000, but also according to the needs of users to use other national departments or other industry standards, or use other national standards (American standard, German

standard, Japanese standard, etc.), if special standards, please indicate when ordering.

The selection of the vortex street flowmeter is a very important work, and the correct selection is the prerequisite for the normal operation of the flowmeter.Statistics show that 70% of the

failure of the flowmeter is caused by the wrong selection or improper installation. Therefore, the flow meter must be selected correctly, and the specific selection methods can refer to the

following several:

1. Selection of instrument type

Piezoelectric vortex street flowmeter has a series of advantages such as wide range ratio, high accuracy, convenient installation and maintenance and wide adaptability of medium, and has good use economy, which is a more commonly used flow metering instrument at present.

Capacitive vortex flowmeter has all the advantages of piezoelectric vortex flowmeter, but also has a high temperature tolerance, temperature adaptation range-50 ℃ ~500 ℃ . Capacitive

vortex street flowmeter signal processing using advanced digital spectrum technology can adapt to a variety of measuring media, lower measurement lower limit, superior

anti-interference and earthquake resistance, realize the ready to use, no adjustment and maintenance.

2. Selection of the installation method

Franka installation is the preferred installation method, because of its compact structure, easy installation, and short supply cycle, suitable for most applications.

Flange connection type is mostly used for integrated differential pressure, pressure, pressure compensation vortex street flow meter and some special applications.

Pipe butt welding type and clamp connection type are suitable for high pressure medium, in which the clamp connection type can be removed.

Thread connection type is mainly used for small caliber, food grade hygiene requirements. Fixed insert and ball valve insertion are suitable for large diameter, generally choose fixed insert, convenient installation, lower cost; ball valve insertion can be continuously flow

maintenance, mostly used for dirty media, easy to scale, need regular cleaning occasions.

3. Determination of the measurement range

The measuring range of different diameter vortex street flowmeter is different, even if the same diameter flowmeter is used in different media, its measuring range is also different. The actual available measurement range is determined by calculation, and the table below provides the flow range of the three typical media under specific conditions.

Reference table for flow range of pipe flowmeter

Reference table for the flow range of the insert flowmeter

The above flow range is the data of three typical media under specific conditions: Liquid media is water:

T=20℃ ρ = 999.8 Kg/m3 µ = 1.0 cp

Gas media is air:

T=20℃ P=101.325kPa (pressure) ρ = 1.293 Kg/m3 µ =0. 084 cp

Steam is superheated steam:

T=188℃ P=0.48 MPa (pressure) ρ = 2.277 Kg / m3 µ = 0. 0

The upper flow rate of the vortex street flowmeter is generally not affected by the working

density and motion viscosity of the medium, while the lower flow rate depends on the working density and motion viscosity of the medium. Therefore, determining the flow range is actually to determine the lower flow rate actually available. When the working conditions of the measuring media change, the lower limit flow value should be corrected according to the actual density

and viscosity.

Density correction: Q1 =Q0 × ρ0 / ρ Adhesion correction: Q2 =Q0 × µ/µ 0

In the formula: Q1 , Q2- the measurable lower limit flow rate of the measuring medium after density and viscosity correction, m3/h

Q0 - Lower limit flow rate of typical medium, m3/h

ρ0 , ρ - Operating density of typical medium and measuring medium, Kg/m3 µ0 , µ - Dynamic viscosity of typical medium and measuring medium, CP

When Q1 > Q2 , the measurable flow range and linear flow range are Q1 ~ Qmax ; for Q1≤ Q2 , the measurable flow range is Q1 ~Qmax , and the linear flow range is Q2 ~ Qmax ; Qmax is the upper limit of typical medium.

4. Selection of nominal diameter

The selection of nominal diameter should first determine the volume flow range of the

measuring medium under the working condition, and then calculate the actual measurable flow range of the pipe diameter. If the flow range of the measured medium is within the actual

measurable flow range of the corresponding diameter, the flow meter with the same diameter as the piping diameter can be selected; if the actual measurable flow range of the

corresponding diameter cannot meet the requirements of the lower limit flow, the diameter

should be reduced and re-calculated; if the actual measurable flow range of the corresponding diameter cannot meet the requirements of the upper limit flow, then the diameter should be

increased and re-calculated.

If only the mass flow rate of the measured medium or the volume flow rate under the standard condition is known, the volume flow rate under the working condition should be converted first and then compared to the actual measurable flow rate range calculated.

The volume flow rate under the mass flow conversion condition is calculated by the following formula:

Q=M/ ρ

In the formula: Q - Operating volume flow rate, m3/h M - Mass flow rate, Kg/h

ρ - Operating medium density, Kg/m3

The volume flow rate under standard conditions is calculated using the following formula:

0.101325 (273.15+T)

Q=-----------×Qb

293.15 (0.101325+P)

In the formula: Qb - Standard volume flow rate, m3/h

P - Working pressure of the medium, gauge pressure MPa T - Working temperature of the medium, ℃

If the working density and motion viscosity of the measuring medium are not much different

from the three typical media, the appropriate 9 nominal diameter can be selected without

checking the table by calculation; if the working density and motion viscosity of the measuring medium are very different from the three typical media, if hydrogen with small density and oil with large viscosity, the vortex street flow meter may not be applicable, and the measurable

flow range should be carefully calculated.

5, the choice of compensation type

The vortex street flowmeter measures the working volume flow, if you need to measure the standard condition flow or mass flow, it needs to make compensation, including differential pressure compensation type, pressure compensation type, temperature compensation type, temperature and pressure compensation type.

Differential pressure compensation vortex street mass flowmeter is a milestone product

developed by our company's research and development team after years of painstaking

research. It is the first in the world and has obtained the national patent. It is a real sense of

vortex street mass flowmeter. Traditional vortex street flowmeter is using the setting density or temperature, pressure compensation density method to calculate the mass of the measuring medium flow, and the density because of the medium component or dry, degree change,

simple by setting density or temperature pressure compensation method cannot reflect this

change, thus produces a technical error. The differential pressure vortex street mass flowmeter developed by our company uses the function of differential pressure and density to calculate the density by measuring the differential pressure. This measurement scheme is not affected by the change of medium component or dry degree, especially suitable for the measurement of unstable mixing gas, liquid, humidity steam and moisture vapor with unstable components. The temperature compensated vortex flowmeter is suitable for measuring the mass flow of

saturated steam with stable pressure; the pressure compensated vortex flowmeter is suitable for measuring the standard flow of gas with little temperature change and the mass flow of

saturated steam; the temperature and pressure compensation vortex flowmeter is suitable for measuring the mass flow of steam and the standard flow of gas, and the compensation

accuracy is higher.

6. Other types of selection

The split vortex street flowmeter is installed in humid environment or high temperature. The circuit part is separated from the sensor to avoid the influence of bad environment on the detection circuit.

The submersible vortex street flowmeter adopts special waterproof process, protection grade IP68, can work underwater for a long time, suitable for the risk of flooding.

The reduced diameter type vortex street flowmeter has a lower flow measurement lower limit, which is suitable for the low medium flow and not convenient for pipe shrinkage.