Selection and Analysis of Bar-Type Flow Meters

Key Factors to Consider for Selection

1. Medium Characteristics

• Fluid Type: Clearly identify whether the fluid is gas, liquid, or steam. Different types of fluids have different adaptabilities to flow meters. For example, Verabar and Delta-Bar meters offer high accuracy in measuring gases and steam. For liquids, factors such as viscosity and corrosiveness need to be considered. Low-viscosity liquids (≤10 cP) can use Verabar meters; for corrosive liquids, Delta-Bar meters are more suitable due to their special materials and structure.
• Temperature and Pressure: Understand the operating temperature and pressure range of the fluid. If the temperature is as high as 650℃ and the pressure is ≤32MPa, the enhanced Pitot-Bar meter can meet the requirements. For extreme working conditions with temperatures ranging from -200℃ to 1240℃ and high pressures up to 68MPa, the Delta-Bar meter is the right choice.

2. Accuracy Requirements

• If extremely high accuracy is required, such as in trade settlement scenarios, the Annubar meter achieves high accuracy under suitable working conditions but requires accepting higher maintenance costs.
• If the accuracy requirement is around ±5% - 10% and cost-effectiveness is a priority, the enhanced Pitot-Bar meter combined with AI compensation can meet the needs in low-flow velocity scenarios.

3. Turndown Ratio Requirements

• When the flow range fluctuates greatly and a large turndown ratio is needed, the Delta-Bar meter (with a turndown ratio of 30:1) and the enhanced Pitot-Bar meter (with a turndown ratio of 50:1) have more advantages.
• For relatively stable flow ranges where the turndown ratio requirement is not high (e.g., 5:1 or 10:1), T-type Bar and Verabar meters can also meet the application needs.

4. Pipeline Conditions

• Pipe Diameter: Large-diameter pipelines (above DN300) are the advantageous application area of bar-type flow meters, and different types are suitable for different pipe diameters. For example, Verabar meters are applicable to pipes with diameters ranging from DN38 to 9000mm; for extra-large diameters (above DN9000mm), the Delta-Bar meter has corresponding models (such as the H150 model).
• Pipeline Shape: Some bar-type flow meters support circular, square, or rectangular pipelines. For instance, Verabar meters are suitable for circular and square pipes, while Annubar meters are applicable to square/rectangular pipelines.

5. Installation and Maintenance Convenience

• Installation Space and Method: Some models support online insertion and removal, such as the H350 model of the Delta-Bar meter, which is suitable for maintenance scenarios without production shutdown. For situations with limited installation space, compact-structured models should be selected.
• Maintenance Frequency and Difficulty: Annubar meters require regular cleaning of pressure taps, with moderate maintenance difficulty. The enhanced Pitot-Bar meters need more frequent maintenance, and their pressure taps should be cleaned every 6 months. Verabar meters have an excellent anti-clogging design, making maintenance relatively simple.

6. Cost Budget

Selection Recommendations for Different Application Scenarios

1. Ultra-Low Flow Velocity Scenarios (<0.6m/s)

• Preferred Option: Multi-channel ultrasonic flow meters can achieve an accuracy of ±3% - 5%, but the cost is relatively high, with a price of approximately 150,000 - 250,000 yuan for DN800.
• Alternative Option: Enhanced Pitot-Bar meter + AI compensation, with an error range of ±5% - 10%, which needs to be used with a high-precision transmitter (e.g., Rosemount 3051S).

2. Conventional Low-Pressure Steam (0.6 - 10m/s)

• Cost-Effective Choice: The Delta-Bar meter has balanced overall performance; the enhanced Pitot-Bar meter can save 20% - 30% of the cost.
• Trade Settlement Scenarios: The Annubar meter meets high accuracy requirements but has high maintenance costs.

3. High-Vibration/Dirty Media

• Anti-Vibration Design: T-type Bar meters have high mechanical strength and are suitable for high-vibration environments. V-cone flow meters have strong anti-fouling capabilities but cause relatively large pressure loss.
• Anti-Clogging Optimization: The bullet-shaped anti-clogging design of Verabar meters and the self-draining design of Delta-Bar meters can effectively handle dirty media and reduce the risk of clogging.

Technological Development Trends of Bar-Type Flow Meters

1. Intelligent Upgrading: Integrate edge computing chips (e.g., STM32H7) to realize real-time filtering and dynamic compensation, reducing reliance on DCS systems and improving the real-time performance and accuracy of measurements.
2. Multi-Sensor Fusion: Combine thermal mass flow meters or humidity sensors to improve measurement accuracy for complex media (e.g., two-phase flow) and meet measurement needs in more special working conditions.
3. Material Innovation: Adopt new materials such as ceramic coatings or Hastelloy to enhance the corrosion resistance and wear resistance of probes in harsh media (corrosive, high-wear environments) and extend their service life.
4. Standardized Protocols: Promote the popularization of communication protocols such as HART and FF to facilitate remote diagnosis and parameter adjustment, and improve the convenience and intelligence of equipment management.