VNFT Clamp-On Ultrasonic Flow Meter

VNFT211 Clamp-On Ultrasonic Flow Meter Small Pipe Size Solution (DN15–DN65)

The VNFT211 ultrasonic flow meter operates based on the transit-time ultrasonic measurement principle. Two external clamp-on ultrasonic transducers are mounted on the outer surface of the pipe. By transmitting and receiving ultrasonic signals upstream and downstream through the pipe wall and liquid medium, the instrument calculates the time difference caused by fluid flow velocity.

This time differential is directly proportional to the flow rate, allowing accurate flow measurement without direct contact with the process medium.

As a non-intrusive measurement solution, VNFT211 eliminates pressure loss, avoids contamination risks, and ensures uninterrupted system operation.

Non-Intrusive Clamp-On Design

• External clamp-on installation without cutting pipes or stopping the process

• No contact with liquid medium, eliminating pressure loss and contamination risk

• Ideal for retrofit projects and continuous operation systems

Fast & User-Friendly Installation

• Installation and commissioning can be completed within minutes

• No special tools or pipeline modification required

• Significantly reduces labor cost and downtime

Flexible Configuration & Wide Compatibility

• One universal sensor set supports all pipe sizes within the measuring range

• Compatible with metal pipes and rigid plastic pipes (PVC, PP, PVDF)

• Suitable for DN15–DN65 pipelines

Clear & Informative Display

• 256 × 128 high-resolution LCD

• Displays flow rate, accumulated flow, status information, and alarms

• Flow readings can be monitored directly on-site

Energy Measurement Capability (Optional)

• Can be configured as an ultrasonic cooling / heating energy meter (BTU meter)

• Supports energy consumption monitoring and management

• Suitable for HVAC, chilled water, and heating applications

Industrial Communication & Output

• Standard 4–20 mA analog output

• Modbus RS485 communication for integration with PLC and DCS systems

• Optional pulse output (OCT) and relay alarm output

• Enables remote monitoring, data acquisition, and efficiency analysis

Reliable Industrial Performance

• Factory low-velocity cutoff at 0.08 m/s to avoid false readings

• Fast response time adjustable from 0.5 to 60 seconds

• Long-term data storage with EEPROM backup (over 10 years)

• Designed for stable operation in harsh industrial environments

Pipe Size Range: DN15 – DN65

Pipe Material: Metal pipes / Rigid plastic pipes (PVC, PP, PVDF)

Liquid Type: Water and other single-phase liquids (No solid particles or impurities)

Temperature Range: 0 to 115 °C (No surface freezing)

Accuracy: ±2% (±1% after calibration)

Response Time: 0.5 – 60 s (adjustable)

Display: 256 × 128 LCD

Power Supply: 10–24 VDC, Power consumption < 3 W

Output & Communication:

• 4–20 mA
• Modbus RS485
• Optional: Pulse output (OCT), relay alarm

Protection & Reliability

• Enclosure: IP65
• Power reverse connection protection
• Surge and short-circuit protection
• Vibration resistance: 10–55 Hz, 1.5 mm
• Shock resistance: 100 m/s², 16 ms

Environmental Conditions

• Ambient temperature: –10 to 60 °C
• Relative humidity: 35–85% RH (non-condensing)
• Housing Material: Aluminum & industrial-grade plastics

• Water supply and distribution systems

• HVAC chilled water and heating circuits

• Energy consumption monitoring

• Industrial process water measurement

• Retrofit projects with limited installation space

Retrofit Flow Measurement in Existing Pipelines

VNFT211 is ideal for flow measurement upgrades in existing systems where pipeline modification is not allowed or downtime must be minimized.
Its clamp-on design enables quick installation without cutting pipes or interrupting operation, making it suitable for:

• Industrial process water lines
• Utility and building water systems
• Temporary flow verification and performance audits
  
  

HVAC Cooling & Heating Energy Monitoring

When configured as an ultrasonic energy (BTU) meter, VNFT211 can be used in chilled water and heating systems to monitor thermal energy consumption.

Typical applications include:

• Chiller inlet and outlet flow monitoring
• Heating and cooling energy distribution systems
• Energy efficiency analysis and cost allocation
  
  

Small-Diameter Pipe Flow Measurement (DN15–DN65)

Designed specifically for small pipe sizes, VNFT211 delivers reliable measurement performance in compact pipeline networks such as:

• Equipment skids and packaged systems
• Laboratory and pilot-scale installations
• Building services and utility branches
  
  

Water Supply and Distribution Systems

VNFT211 provides stable flow monitoring for clean water applications without pressure loss, supporting:

• Water supply balancing
• Leak detection and abnormal flow analysis
• System optimization and operational efficiency improvement
  
  

Temporary Measurement & Diagnostic Testing

Due to its fast installation and portability, VNFT211 is well-suited for short-term measurement tasks, including:

• Commissioning and system validation
• Comparative testing between flow meters
• Troubleshooting flow anomalies without permanent installation
  
  

Automation and Control System Integration

With standard 4–20 mA output and Modbus RS485 communication, VNFT211 can be seamlessly integrated into automation systems for:

• PLC and DCS flow data acquisition
• Central control room monitoring
• Data logging, reporting, and process optimization