1. Highlights of Insertion Ultrasonic Flow Meters
01Pipe Diameter Pipelines
Insertion ultrasonic flow meters are particularly suitable for large-diameter pipelines where installing a traditional flanged flow meter can be expensive, heavy, or difficult.
Instead of replacing a section of the pipeline, insertion sensors are installed directly through openings made in the pipe wall. This makes the installation more flexible for large water supply, cooling water, process water and industrial pipelines.
02Suitable for Difficult Pipe Materials
Insertion ultrasonic sensors can be a practical solution when clamp-on sensors have difficulty obtaining a strong and stable ultrasonic signal.
They can be used on various pipe materials, including steel, stainless steel, cast iron and other commonly used industrial pipeline materials, provided that the selected installation location and sensor configuration are suitable.
03Better Signal Transmission Through the Pipe Wall
With clamp-on ultrasonic flow meters, the ultrasonic signal must pass through the pipe wall, possible coatings or liners, and the coupling layer before entering the liquid.
Insertion sensors are installed directly through the pipe wall and extend into the flowing liquid. This can reduce the influence of some pipe-wall conditions and provide a more direct ultrasonic measurement path.
04Suitable for Large or Difficult-to-Access Pipes
For large pipelines, installing a full-bore flow meter may require significant pipe modification, shutdown time and installation cost.
An insertion flow meter normally requires only suitable sensor mounting points on the existing pipeline. This makes it attractive for retrofit projects and existing water distribution systems.
05Suitable for Certain Lined or Scaled Pipes
Pipe liners, corrosion, deposits and scale can affect ultrasonic transmission when using clamp-on sensors.
When the pipe condition makes external ultrasonic transmission difficult, an insertion sensor can provide an alternative measurement method. However, the actual pipe condition should still be checked before installation.
2. What Types of Applications Are Suitable for Insertion Ultrasonic Flow Meters?
Insertion ultrasonic flow meters are commonly considered for applications where a conventional inline flow meter or clamp-on ultrasonic flow meter is not the most practical choice.
Large-Diameter Water Pipelines
Large-diameter pipelines are one of the typical applications.
For example, insertion ultrasonic flow meters can be considered for:
Large-diameter pipelines are one of the typical applications
For example, insertion ultrasonic flow meters can be considered for:
Raw water pipelines
Water supply networks
Cooling water systems
Industrial process water
Irrigation pipelines
Circulating water systems
Municipal water transmission pipelines
For these applications, the cost and difficulty of installing a full-bore flow meter can increase significantly as pipe diameter increases.
An insertion design can therefore provide a more flexible retrofit solution.
Existing Pipelines That Cannot Easily Be Replaced
Many industrial facilities already have pipelines installed underground, inside plants or in locations where pipeline modification is difficult.
In these situations, removing a section of pipe to install a conventional flow meter may require extensive work.
An insertion ultrasonic flow meter can be installed by creating suitable mounting openings on the existing pipeline, making it useful for flow measurement upgrades and retrofit projects.
Pipes With Difficult External Ultrasonic Transmission
Clamp-on ultrasonic flow meters require ultrasonic energy to travel through the pipe wall and into the liquid.
Heavy corrosion, thick pipe walls, internal liners, coatings or significant deposits can make signal transmission more difficult.
When the clamp-on method cannot provide sufficient signal strength or stable measurement, an insertion sensor may be considered as an alternative.
Large Pipes With Internal Lining
Some pipelines are equipped with rubber, plastic or other internal liners for corrosion protection or process requirements.
These liners can affect ultrasonic transmission from outside the pipe.
For such applications, insertion measurement may provide a more suitable configuration because the sensor is installed through the pipe wall and measures the liquid more directly.
However, the liner thickness, material and installation method must be considered before selecting the sensor.
Pipelines With Existing Scale or Deposits
Scale and deposits can change the ultrasonic transmission path and may reduce the signal quality of externally mounted sensors.
If the pipeline has significant deposits but the insertion sensor can be correctly positioned in the flowing liquid, an insertion configuration may offer better measurement conditions.
The actual internal pipe condition should always be evaluated before installation.
3. Why Choose an Insertion Ultrasonic Flow Meter Instead of a Clamp-on Type?
The main difference is the ultrasonic transmission path.
A clamp-on ultrasonic flow meter installs the transducers outside the pipeline. The ultrasonic signal needs to pass through the pipe wall before reaching the liquid.
An insertion ultrasonic flow meter installs the sensors through the pipe wall, with the sensing elements positioned directly in the liquid.
Therefore, when pipe-wall conditions make external signal transmission difficult, insertion measurement can provide an alternative solution.
This is especially useful for:
Large pipe diameters
Thick-wall pipelines
Certain lined pipelines
Pipes with external mounting limitations
Applications where clamp-on signal strength is insufficient
Retrofit projects requiring a practical installation method
The choice should always be based on the actual pipe material, pipe diameter, liner, liquid properties, flow conditions and required accuracy.
4. What Liquid Can Be Measured?
Insertion transit-time ultrasonic flow meters are generally suitable for liquids that can transmit ultrasonic energy effectively.
Typical applications include:
Clean water
Raw water
Cooling water
Chilled water
Process water
Treated water
Industrial water
Some chemical liquids
For liquids containing a significant amount of suspended solids or air bubbles, the ultrasonic measurement principle and sensor type need to be selected carefully.
For liquids with sufficient suspended particles or bubbles, a Doppler ultrasonic flow meter may be more appropriate than a transit-time flow meter.
Therefore, the liquid condition is an important factor in flow meter selection.
5. What Pipeline Conditions Are Required?
Although insertion ultrasonic flow meters are suitable for many difficult applications, installation conditions still have a major influence on measurement performance.
Full Pipe Condition
-
For a conventional insertion transit-time ultrasonic flow meter, the measuring pipe should normally remain completely filled with liquid.
- Avoid installation locations where air can accumulate at the top of the pipe or where sediment can accumulate around the bottom of the pipe.
Stable Flow Profile
The sensor should preferably be installed in a section of pipe where the flow is relatively stable.
Avoid locations immediately downstream of:
Pumps
Fully or partially closed valves
Elbows
Tees
Reducers
Other strong flow disturbances
A suitable straight pipe section helps establish a more stable velocity profile and improves measurement reliability. A common installation guideline is to provide approximately 10D upstream and 5D downstream straight pipe length, although the actual requirement should follow the specific flow meter manufacturer’s installation instructions.
Suitable Vertical Pipe Installation
For vertical pipelines, upward flow is generally preferred.
An upward flow direction helps keep the pipe full and reduces the possibility of air accumulation at the measurement point.
Downward-flowing vertical sections should be evaluated carefully because changes in pressure and flow conditions may increase the risk of an incompletely filled pipe.
6. When Is Insertion Better Than a Traditional Inline Flow Meter?
An insertion flow meter can be attractive when the pipeline is already in operation and replacing a pipe section is inconvenient.
For example, consider a DN800 water pipeline in an existing industrial facility.
Installing a conventional flanged flow meter may require:
- Shutting down the pipeline
- Cutting and removing part of the existing pipe
- Installing a new flanged spool
- Aligning the pipeline
- Installing the flow meter
- Testing the system before returning it to operation
An insertion flow meter can reduce the amount of pipeline modification required because the sensors are mounted through the pipe wall.
This makes insertion technology particularly attractive for large-diameter retrofit applications.
7. What Should Be Checked Before Selecting an Insertion Flow Meter?
Before selecting the meter, the following information should normally be confirmed:
Parameter Why It Matters
Pipe diameter Determines sensor configuration and installation method
Pipe material Affects installation and ultrasonic transmission
Pipe wall thickness Important for sensor selection and installation
Pipe liner May affect sensor installation and measurement
Liquid type Determines whether transit-time or Doppler technology is suitable
Liquid temperature Determines sensor material and operating limits
Operating pressure Important for the insertion assembly and valve arrangement
Flow velocity Helps determine measurement range
Pipe condition Scale, corrosion and deposits may affect installation
Installation space Determines whether sensors can be installed correctly
Straight pipe length Helps ensure a stable flow profile
Providing these parameters to the flow meter supplier can significantly improve model selection and installation planning.
8. What Are the Main Advantages of an Insertion Ultrasonic Flow Meter?
An insertion ultrasonic flow meter provides several advantages for specific industrial applications:
Suitable for large-diameter pipelines
Practical for existing pipeline retrofit projects
Requires less pipeline modification than many conventional inline meters
Can be considered when clamp-on ultrasonic measurement is difficult
Suitable for various industrial water applications
Sensors can be installed directly into the flowing liquid
Flexible installation for large and difficult-to-modify pipelines
However, insertion ultrasonic flow meters are not automatically the best solution for every application.
The liquid properties, pipe condition, flow profile, pressure, temperature and required accuracy should all be considered before selection.
Post time: Sep-10-2026