Solidat Vortex Flowmeter Application
Dec 09, 2025| SLDF7210 Integral Vortex Flowmeter Product Technical Documentation
Abstract: The SLDF7210 is an integral vortex flowmeter designed based on the Kármán vortex street principle, suitable for measuring the flow of steam, gas, and low-viscosity liquids. This product integrates temperature and pressure compensation functions, enabling direct output of mass flow signals. It features a wide measurement range, high accuracy, excellent stability, and easy installation and maintenance, making it an ideal choice for flow measurement in industrial processes.
Keywords: Vortex Flowmeter, Kármán Vortex Street, Strouhal Number, Steam Measurement, Flow Measurement, Integral Compensation, SLDF7210
1. Product Overview
The SLDF7210 vortex flow sensor measures the flow of steam, gas, and low-viscosity liquids based on the theories of Kármán and Strouhal concerning vortex generation and the relationship between vortices and flow rate. Its design integrates sensing, compensation, and display functions into a single unit, providing high-precision volumetric and mass flow data to meet the high demands of modern industrial flow measurement.
2. Working Principle
A triangular prism, acting as the vortex shedder, is inserted vertically into the meter body. When fluid flows through the meter body, regular Kármán vortices are alternately generated on opposite sides of the prism. The separation frequency (F) of these vortices is proportional to the flow velocity (V) of the medium. By detecting the number of vortices with the sensor head, the fluid velocity can be calculated, and subsequently, the volumetric flow rate is determined based on the meter's caliber.
Core Calculation Formulas:
F = Sr × V / (1 - 1.27 × d / D) (Formula 1)
F: Vortex frequency generated as fluid passes the triangular prism (Hz)
Sr: Strouhal number (dimensionless)
V: Fluid velocity in the pipeline (m/s)
d: Width of the triangular prism within the vortex meter body (m)
D: Inner diameter of the vortex meter body (m)
Q = 3600 × F / K (Formula 2)
Q: Volumetric flow rate (m³/h)
K: Meter factor of the vortex flowmeter (pulses per cubic meter)
M = Q × ρ (Formula 3)
M: Instantaneous mass flow rate (kg/h)
ρ: Fluid density (kg/m³)
The meter factor K is obtained through practical flow calibration and represents the number of vortices generated per cubic meter of fluid passing the triangular prism.
3. Product Features
Wide Applicability: Suitable for flow detection of various gases, liquids, and steam.
Superior Stability: Anti-vibration sensor design with excellent resistance to vibration and interference. No moving parts ensure long-term stable and reliable operation.
Integral Design: Integrated temperature and pressure compensation structure for direct mass flow measurement.
High Performance: Wide measurement range and high accuracy. Turndown ratio can reach 1:15.
Low Power Consumption: Utilizes a low-power CPU and LCD display.
Economical and Efficient: Low pressure loss, low operating costs, easy installation and maintenance. Calibration cycle is typically two years.
Stable Output: Within a certain Reynolds number range, the output signal is unaffected by changes in the physical properties and composition of the measured medium.
4. Main Technical Parameters
|
Parameter |
Specifications |
|
Measuring Medium |
Gas, Liquid, Steam |
|
Caliber Specifications |
Flange Clamp Type / Flange Type: DN15 ~ DN300mm |
|
Flow Velocity Range |
Gas: 4 ~ 40 m/s |
|
Accuracy |
Flange Clamp/Flange Type: ±1.0% or ±1.5% |
|
Medium Temperature |
Standard Type: -25℃ ~ 100℃ |
|
Nominal Pressure |
1.6 MPa, 2.5 MPa, 4.0 MPa (Customizable) |
|
Output Signal |
Pulse Voltage (High Level: 8~10V, Low Level: 0.7~1.3V; Explosion-Proof: High Level: 4~5V) |
|
Power Supply |
DC12V±10%; DC24V±10%; Lithium Battery 3.6V 7.5Ah 2 cells |
|
Explosion-Proof Rating |
Intrinsic Safety ExiallCTI-T5 | Flameproof ExdIIBT4 |
|
Protection Rating |
IP65 |
|
Body Material |
Meter Body: 304 Stainless Steel (316L available on request); Converter Housing: Aluminum Alloy |
5. Flow Measurement Range Selection Table
5.1 Liquid and Normal Temperature/Pressure Air Flow Range (m³/h)
|
Diameter (mm) |
Liquid Measurement Range |
Gas Measurement Range |
|
15 |
0.8 - 6 |
6 ~ 40 |
|
25 |
1.5 - 12 |
10 ~ 80 |
|
50 |
3 - 50 |
30 ~ 300 |
|
100 |
12 - 200 |
120 ~ 1200 |
|
200 |
50 - 800 |
400 ~ 4000 |
|
300 |
100 - 1600 |
1000 ~ 10000 |
*Note: Please refer to the complete document for more detailed calibers.*
5.2 Superheated Steam Mass Flow Range (kg/h)
|
Diameter (mm) |
Lower Limit Flow |
Upper Limit Flow |
|
25 |
13.1√ρ |
131√ρ |
|
100 |
164.7√ρ |
1647√ρ |
|
300 |
1647√ρ |
16470√ρ |
*Note: ρ is the operating density of the superheated steam. The maximum flow velocity should generally not exceed 70 m/s. Please refer to the complete pressure-diameter comparison table for saturated steam flow ranges.*
6. Structure and Installation
6.1 Outline and Dimensions
The instrument offers two main structures: flange-connected and insertion type. The flange-connected type is suitable for small and medium-diameter pipelines, featuring a compact structure.
Flange-Connected Type Outline Dimensions Example (Partial):
|
Nominal Diameter (mm) |
Body Length L (mm) |
Flange Outer Diameter D3 (mm) |
Number of Bolt Holes n |
|
25 |
170 |
150 |
4 |
|
50 |
190 |
165 |
4 |
|
100 |
240 |
220 |
8 |
|
200 |
300 |
340 |
12 |
|
300 |
400 |
460 |
12 |
The insertion type vortex flowmeter is primarily used for large-diameter pipelines and offers high cost-effectiveness.
6.2 Installation Requirements
Installation Location: The sensor should be installed on horizontal, vertical, or inclined (liquid flowing upward) pipelines corresponding to its nominal diameter.
Straight Run Requirements: Sufficient straight pipe sections upstream and downstream of the sensor are required to ensure stable flow conditions. Specific requirements are as follows:
Concentric reducer / Full-open valve: Upstream ≥ 15D, Downstream ≥ 5D
One 90° bend: Upstream ≥ 15D, Downstream ≥ 5D
Control valve / Half-open valve: Upstream ≥ 15D, Downstream ≥ 5D
(D is the pipe diameter)
Precautions:
The part of the installation base inserted into the pipeline must not protrude beyond the inner pipe wall.
The base position on the pipeline must be correct and not skewed; the flange face must be parallel to the pipeline axis.
Remove burrs and welding slag inside the pipeline before installation.
Ensure the medium flow direction is consistent with the flow direction indicator on the meter housing. Do not force the flow direction indicator.
7. Application Fields
The SLDF7210 vortex flowmeter is widely used for steam, gas, and liquid flow measurement in the following fields:
Energy Industry: Boiler steam measurement, district heating.
Petrochemical Industry: Feedstock gas, process gas, and various liquid monitoring and control.
Metallurgy, Papermaking, Pharmaceuticals: Compressed air, industrial water, process steam measurement.
Environmental Protection & Municipal: Large pipeline gas flow measurement.
8. Conclusion
The SLDF7210 integral vortex flowmeter is a technologically advanced and highly reliable industrial-grade flow instrument. Its design based on physical principles ensures measurement accuracy and repeatability. The wide rangeability and integrated temperature-pressure compensation functionality greatly meet measurement requirements in complex working conditions. Combined with its robust structure, simple installation and maintenance, and good environmental adaptability, the SLDF7210 presents a cost-effective optimal solution in the field of industrial flow measurement, providing users with stable and precise flow data support.