Non intrusive ultrasonic flow meter is a cutting-edge technology that enables flow measurement without cutting pipes or contacting the fluid. By simply clamping sensors on the outside of a pipe, it offers a fast, clean, and non-disruptive solution—ideal for applications where hygiene, safety, or uninterrupted operation is critical. As industries increasingly seek efficient and maintenance-free measurement tools, this type of flow meter is becoming a preferred choice in water treatment, HVAC, chemical, and many other fields.
What Is a Non-Intrusive Ultrasonic Flow Meter?
A non-intrusive ultrasonic flow meter (also called clamp-on flow meter) uses ultrasonic waves transmitted through the pipe wall to measure the velocity of liquids inside. The sensors are clamped on the outside of the pipe — no need for cutting, welding, or process interruption.
How It Works?
There are two main working principles:
Transit-Time Method:
- Used for clean, single-phase liquids
- Ultrasonic signals are sent both upstream and downstream
- The time difference between the two directions is used to calculate flow rate
Doppler Method:
- Used for liquids with bubbles or suspended solids
- Measures the frequency shift of reflected sound waves from moving particles
- Less accurate, but suitable for dirty or mixed fluids
Types of Non-Intrusive Ultrasonic Flow Meters
| Classification | Type | Description | Typical Use |
| By Principle | Transit-Time | High accuracy, clean liquids | Water, chilled water, chemicals |
| Doppler | For dirty or aerated fluids | Wastewater, slurries | |
| By Usage | Fixed Type | Mounted permanently | Factories, pipelines |
| Portable Type | Handheld, mobile use | Field testing, temporary monitoring | |
| By Installation | Clamp-On | Fully external, no pipe cutting | All pipe materials |
| (Insert Type) | Semi-invasive, rarely used in this context | High-precision needs only |
Non-Intrusive Ultrasonic Flow Meter Suitable for Measuring Media
Ideal for:
- Clean water (drinking water, industrial water)
- Chilled water / cooling water
- Low-viscosity chemicals
- Alcohol, ethanol
- Slightly dirty water (if using Doppler method)
Not suitable for:
- Gases (air, steam, etc.)
- Very high-viscosity liquids (like oil sludge or glue)
- Highly aerated fluids (boiling liquids or heavy aeration)
- Dense slurry or thick mud
Advantages of Non-Intrusive Ultrasonic Flow Meter
- Non-invasive: No pipe cutting, welding, or downtime
- No risk of leakage or contamination
- Easy to install and remove
- No pressure drop
- Works with metal, PVC, stainless steel pipes
- Available in portable and fixed models
- Supports outputs like 4–20mA, RS485, Modbus
Disadvantages of Non-Intrusive Ultrasonic Flow Meters
- Measurement accuracy is slightly lower than inline flow meters (±1–3%)
- Pipe condition (e.g., rust, scale, paint) can affect signal transmission
- Not suitable for gas or very viscous fluids
- Sensor installation needs precision; incorrect mounting can cause errors
- Sensitive to ambient vibration and extreme temperatures
Application Areas of Non-Intrusive Ultrasonic Flow Meters
- Municipal water supply monitoring
- Cooling and HVAC systems
- Food and beverage factories
- Chemical plants and pharmaceuticals
- Energy plants and power stations
- Industrial wastewater measurement
- On-site flow audits (using portable versions)
Why Choose Apure?
At Apure, we offer a wide range of non-intrusive clamp-on ultrasonic flow meters for both portable and permanent installations. Our models feature:
- Accurate transit-time or Doppler measurement
- Support for pipe diameters from DN15 to DN2000
- Digital displays and data logging
- Industrial-grade enclosures (IP65+ rated)
- Multi-output options for easy integration
Summary
Non-intrusive ultrasonic flow meters offer quick installation, no process interruption, and clean measurement — ideal for monitoring various liquids without touching the flow. Despite some limits in accuracy and media type, they remain a versatile, low-maintenance solution for both temporary and permanent applications.
At Apure, besides non intrusive ultrasonic flow meters, we also offer a variety of other flow measurement solutions including electromagnetic flow meters, vortex flow meters, and turbine flow meters. This comprehensive product range ensures that we can meet diverse application needs and provide the most suitable flow measurement technology for your specific process. If you need it, please contact us.