The TX-LUGB series steam meter is mainly used for measuring the flow rate of steam medium fluid in industrial pipelines. The characteristics of steam vortex flowmeter are small pressure loss, large range, high accuracy, and it is almost not affected by fluid density, pressure, temperature, viscosity and other parameters when measuring the volumetric flow rate under working conditions. No movable mechanical parts, therefore high reliability and low maintenance. The instrument parameters can remain stable for a long time. The steam flowmeter adopts a piezoelectric stress sensor, which has high reliability and can operate within the working temperature range of -20 ℃ to+250 ℃. It has both analog standard signals and digital pulse signal outputs, making it easy to use in conjunction with digital systems such as computers. It is a relatively advanced and ideal flow meter.

1、 Working principle of TX-LUGB steam meter
When a triangular cylindrical vortex generator is set up in a steam fluid, regular vortices are alternately generated from both sides of the vortex generator, which are called Karman vortices. As shown in the figure on the right, the vortex columns are asymmetrically arranged downstream of the vortex generator.
Assuming the frequency of vortex occurrence is f, the average flow velocity of the measured medium is, the width of the upstream surface of the vortex generator is d, and the diameter of the body is D, the following relationship can be obtained:
In the formula f=SrU1/d=SrU/md:（1）
U1- average flow velocity on both sides of the vortex generator, m/s；
Sr Strouhal number;
M - the ratio of the bow shaped area on both sides of the vortex generator to the cross-sectional area of the pipeline;

The volumetric flow rate qv inside the pipeline is
qv=πD2U/4=πD2mdf/4Sr ； 　　　　　　　　　　　　　　　　 (2)
K=f/qv=[πD2md/4Sr]-1 ； 　　　　　　　　　　　　　　　　 (3)
In the formula, K represents the instrument coefficient of the flowmeter, measured in pulses per cubic meter (P/m3);
K is not only related to the geometric dimensions of the vortex generator and pipeline, but also to the Strouhal number. The Strouhal number is a dimensionless parameter that is related to the shape of the vortex generator and the Reynolds number. Figure 2 shows the relationship between the Strouhal number of a cylindrical vortex generator and the Reynolds number of a pipeline. As shown in the figure, Sr can be regarded as a constant within the range of ReD=2 × 104 to 7 × 106, which is the normal operating range of the instrument.
Figure 2: The relationship curve between Strouhal number and Reynolds number
In the equation, qVn and qV - represent the volumetric flow rates under standard conditions (0oC or 20oC, 101.325kPa) and operating conditions, respectively, m3/h；
Pn and P - are the absolute pressures under standard and operating conditions, respectively, Pa；
Tn and T - are the thermodynamic temperatures under standard and operating conditions, respectively, K；
Zn and Z - are the gas compression coefficients under standard and working conditions, respectively.
As can be seen from the above equation, the pulse frequency signal output by VSF is not affected by fluid properties and composition changes, that is, the instrument coefficient is only related to the shape and size of the vortex generator and pipeline within a certain Reynolds number range. However, as a flowmeter in material balance and energy measurement, it is necessary to detect mass flow rate. At this time, the output signal of the flowmeter should simultaneously monitor volume flow rate and fluid density. Fluid properties and components still have a direct impact on flow measurement.
The TX-LUGB steam meter is a new type of flow meter used for measuring fluid flow in closed pipelines based on the Karman vortex principle. Due to its excellent medium adaptability, it can directly measure the volumetric flow rate of steam, air, gas, water, and liquid without temperature and pressure compensation. Equipped with temperature and pressure sensors, it can measure standard volumetric flow rate and mass flow rate, making it an ideal alternative to throttling flow meters.
To improve the high temperature resistance and vibration resistance of TX-LUGB steam meters, our company has recently developed the JTLUG improved vortex flow sensor. Due to its unique structure and material selection, the sensor can be used in harsh working conditions such as high temperature (350 ℃) and strong vibration (≤ 1g).
In practical applications, the maximum flow rate is often much lower than the upper limit of the instrument, and with changes in load, the minimum flow rate is often lower than the lower limit of the instrument. The instrument is not working in its optimal working range. To solve this problem, it is usually necessary to reduce the diameter at the measuring point to increase the flow rate at the measuring point, and use smaller diameter instruments to facilitate the measurement of the instrument. However, this variable diameter method requires a straight pipe section with a length of more than 15D between the variable diameter pipe and the instrument for rectification, which makes processing and installation inconvenient. Our company has developed an LGZ variable diameter rectifier with a curved longitudinal section, which has multiple functions such as rectification, increasing flow velocity, and changing flow velocity distribution. Its structural size is small, only one-third of the inner diameter of the process pipe, and it is integrated with the vortex flowmeter. It not only does not require an additional straight pipe section, but also reduces the requirements for the straight pipe section of the process pipe, making installation very convenient.
For the convenience of use, the battery powered on-site display steam vortex flowmeter adopts low-power high-tech. It can operate continuously for more than a year using lithium battery power supply, saving the procurement and installation costs of cables and display instruments. It can display instantaneous flow, cumulative flow, etc. on-site. The temperature compensated integrated vortex flowmeter also comes with a temperature sensor, which can directly measure the temperature of saturated steam and calculate the pressure, thereby displaying the mass flow rate of saturated steam. The temperature pressure compensation integrated type is equipped with temperature and pressure sensors, which can directly measure the temperature and pressure of the gas medium for gas flow measurement, thereby displaying the standard volume flow rate of the gas.
Measurement medium: gas, liquid, vapor
◆ Caliber specifications: Flange card mounted caliber selection: 25, 32, 50, 80, 100
◆ Flange connection type with a diameter selection of 100, 150, 200
◆ Flow measurement range Normal measurement flow velocity range Reynolds number 1.5 × 104~4 × 106; Gas velocity of 5-50m/s; Liquid 0.5-7m/s
The normal measurement range for liquid and gas flow is shown in Table 2; The steam flow range is shown in Table 3
Measurement accuracy level 1.0 and 1.5
◆ Temperature of the tested 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 of 1000m
◆ Instrument operating environment temperature: -25 ℃~+55 ℃ humidity: 5-90% RH50 ℃
◆ Material: Stainless steel, aluminum alloy
◆ Power supply DC24V or lithium battery 3.6V
Explosion proof grade intrinsic safety type iaIIbT3-T6
◆ Protection level IP65
TX-LUGB Steam GaugeProduct Selection