Clamp-connected vortex flowmeter
Vortex flowmeter is also called vortex flowmeter or Karman vortex flowmeter . Realize product intelligence, standardization, serialization, generalization, production mold, and ensure the aesthetics of product quality.
The product has the characteristics of low power consumption, wide range ratio, simple structure, low resistance loss, sturdiness and durability, wide use, long service life, stable work, and easy installation and debugging.
The vortex flowmeter has the following characteristics:
The structure is simple and firm, with no moving parts, high reliability, and reliable long-term operation.
Simple installation and convenient maintenance.
The detection sensor does not directly contact the measured medium, with stable performance and long life.
The output is a pulse signal proportional to the flow rate , with no zero drift and high accuracy .
The measurement range is wide, and the range ratio can reach 1:10.
The pressure loss is small, the operating cost is low, and it is more energy-saving.
Within a certain range of Reynolds number , the output signal frequency is not affected by the physical properties and composition changes of the fluid . The meter coefficient is only related to the shape and size of the vortex generator. There is no need to compensate when measuring the volume flow of the fluid , and there is generally no need to renew after changing the accessories. Calibration instrument factor.
It has a wide range of applications, and the flow of steam, gas and liquid can be measured.
The verification period is two years.
The LUGB type vortex flow sensor has an inner diameter range of 25-300mm (full tube type), and the KTLUI type plug-in vortex flow sensor has an application inner diameter range of 350-1200mm (plug-in type). The full tube type measures liquid with an accuracy of 1%. The accuracy of steam and gas is 1.5%, the accuracy of plug-in measuring liquid is 2%, the accuracy of measuring steam and gas is 2.5%, and the temperature of the measured medium is -20~150℃, -40~250℃, +100~350℃ (only Tube type), the output signal is three-wire system voltage pulse , three-wire system 4-20mA, two-wire system 4-20mA.
◆Measuring medium: gas , liquid , steam
◆ connection mode: Flange card-mounted, flange , plug-
◆Flow measurement range Normal measurement flow velocity range Reynolds number 1.5×104～4×106; gas 5～50m/s; liquid 0.5～7m/s
The normal measurement flow range of liquid and gas flow measurement range is shown in Table 2; the steam flow range is shown in Table 3
◆ Measurement accuracy 1.0 grade 1.5 grade
◆The temperature of the measured medium : normal temperature -25℃～100℃, high temperature -25℃～150℃ -25℃～250℃
◆Output signal pulse voltage output signal high level 8～10V low level 0.7～1.3V
◆The pulse duty cycle is about 50%, and the transmission distance is 100m
◆ Pulse current remote transmission signal 4～20 mA, transmission distance is 1000m
◆ Environmental temperature of the instrument : -25℃～+55℃ Humidity: 5～90% RH50℃
◆Material stainless steel, aluminum alloy
◆Power supply DC24V or lithium battery 3.6V
◆ Explosion-proof grade intrinsically safe type iaIIbT3-T6, protection grade IP65
Disposed in the fluid triangular prism type vortex of, from both sides of the body to produce a regular vortex vortices alternately, this vortex is called Karman vortex, the vortex column body asymmetrically arranged downstream vortex.
The vortex flowmeter is a Karman vortex street principle (Ká RM measuring gas, vapor or liquid án Vortex Street) the volume flow rate, standard conditions of the volume flow or mass flow of the volume meter. It can be used as a flow transmitter in automation control systems .
The vortex flowmeter uses the principle of fluid oscillation to measure flow. When the fluid passes through the vortex flow transmitter in the pipeline, two rows of vortices proportional to the flow rate are alternately generated up and down after the vortex generator of the triangular column. The release frequency of the vortex is proportional to the flow rate. The average velocity of the fluid flowing through the vortex generator is related to the characteristic width of the vortex generator, which can be expressed by the following formula:
Where: is the release frequency of the vortex , in Hz; v is the average velocity of the fluid flowing through the vortex generator, in m/s; d is the characteristic width of the vortex generator, in m; Sr is Strouhal number (Strouhal number), dimensionless , its value in the range of 0.14-0.27.
St is a function of Reynolds number .
When the Reynolds number Re is within the range, the value of St is about 0.2. In the measurement, try to satisfy the Reynolds number of the fluid and the vortex frequency at this time.
Therefore, by measuring the frequency of the vortex, the average velocity v of the fluid flowing through the vortex generator can be calculated, and then the flow rate q can be obtained from the formula, where A is the cross-sectional area of the fluid flowing through the vortex generator.
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