When selecting a clamp-on ultrasonic flow meter, engineers are often asked for several pipeline parameters before the right sensor configuration can be confirmed.
This is not just paperwork. Pipe size, material, wall thickness, liquid properties and flow conditions all affect how the ultrasonic signal travels through the pipeline and how well the meter can measure the flow.
If you are requesting a quotation or checking whether a clamp-on ultrasonic flow meter will work on an existing pipeline, the following information is usually enough to start.
1. Pipe Diameter
The pipe diameter is one of the first things to confirm.
For clamp-on ultrasonic flow measurement, the sensor size and installation position are related to the pipe diameter. A DN25 pipe and a DN500 pipe cannot normally use the same sensor configuration.
If possible, provide:
Nominal pipe size
Outside diameter
Pipe circumference, if the exact diameter is unknown
For an existing pipeline, measuring the outside diameter directly can sometimes be more useful than relying only on the nominal pipe size.
2. Pipe Material
Tell the supplier what the pipe is made of.
Common examples include:
Carbon steel
Stainless steel
Cast iron
PVC
HDPE
Copper
Other rigid plastic or metal pipes
Different materials transmit ultrasonic signals differently. This can affect sensor selection and signal strength.
If the pipeline has been modified or repaired, it is also worth checking whether the actual material is different from the original drawing.
3. Wall Thickness
Wall thickness is another important parameter for clamp-on measurement.
The ultrasonic signal has to pass through the pipe wall before entering the liquid. A thicker wall can increase signal attenuation and may affect the suitable sensor configuration.
If you know the pipe specification, provide the wall thickness directly.
If you do not know it, you can usually provide the pipe standard, model or a photo of the pipe marking first. The supplier can then help determine what additional information is needed.
4. Is There an Internal Lining?
This question is easy to overlook.
Some pipelines have an internal lining, such as rubber, PTFE or another protective material. The lining creates an additional layer between the sensor and the liquid and changes the ultrasonic transmission path.
Therefore, tell the supplier whether the pipe is:
Unlined
Rubber lined
PTFE lined
Cement lined
Other lined pipe
If the lining material and thickness are known, provide them as well.
5. What Liquid Are You Measuring?
"Water" is useful information, but the actual medium should be stated as accurately as possible.
For example:
Cooling water
Process water
Glycol solution
Hydraulic oil
Chemical solution
Wastewater
Other process liquid
The liquid needs to be suitable for ultrasonic measurement and should normally provide a continuous liquid path through the pipe.
If the liquid contains a large amount of gas, solids or bubbles, mention this during the selection stage rather than after installation.
6. Temperature
Provide the normal liquid temperature, and preferably the minimum and maximum temperature.
For example:
Liquid temperature: 20–60°C
Temperature is important because liquid properties and ultrasonic propagation can change with temperature. It is also important when selecting sensors for hot pipelines.
If the pipe itself is very hot or insulated, mention that too.
7. Minimum, Normal and Maximum Flow
Do not provide only one flow value if the operating range is known.
A better format is:
| Flow condition | Flow rate |
|---|---|
| Minimum | 5 m³/h |
| Normal | 20 m³/h |
| Maximum | 35 m³/h |
This gives the supplier a much better picture of the actual measurement conditions.
A very low flow rate may require more attention to pipe diameter and flow velocity. On the other hand, a large maximum flow may require checking the upper measurement range.
8. Pipe Insulation
Tell the supplier whether the pipe has insulation.
For example:
Pipe: stainless steel, DN100, 3 mm wall thickness, 50 mm insulation
The insulation itself is normally not the surface where the ultrasonic sensors are installed. For a typical clamp-on installation, a small section of insulation is removed so that the sensors can be coupled directly to the pipe wall.
This is especially important for hot-water and steam-related industrial environments.
9. Installation Environment
Finally, describe where the flow meter will be installed.
Useful information includes:
Indoor or outdoor installation
Available straight pipe length
Nearby pumps
Valves or elbows
Pipe accessibility
Ambient temperature
Hazardous area requirements, if applicable
Whether the pipeline can be temporarily accessed for installation
You do not need to prepare a complete engineering drawing for the first inquiry. A simple photo of the pipeline can often help clarify the installation conditions.
A Simple Parameter List for Your Inquiry
If you want to ask a supplier for a clamp-on ultrasonic flow meter, you can start with this:
Pipe diameter:
Pipe material:
Wall thickness:
Internal lining:
Liquid:
Liquid temperature:
Flow range:
Pipe insulation:
Output signal:
Power supply:
Installation environment:
For the first technical review, the most important information is usually pipe diameter, pipe material, wall thickness, liquid, temperature and minimum/normal/maximum flow.
If some information is unavailable, do not guess. Tell the supplier what you know and identify what is missing. In many cases, a pipe photo, nameplate or pipeline drawing can help fill in the details.
What Happens After You Provide the Parameters?
The supplier can then check whether the clamp-on ultrasonic method is suitable and determine the appropriate sensor configuration.
For example, HONNO's HNF100 wall-mounted clamp-on ultrasonic flow meter covers a wide range of pipe sizes, with sensor configurations selected according to the actual pipeline conditions. The system can be used for measurement on existing pipelines without cutting the pipe or interrupting the process, when the application is suitable.
For a new project, providing complete pipeline information at the beginning can avoid repeated questions and make the selection and quotation process much faster.
FAQ
Do I need to know the exact pipe wall thickness?
It is strongly recommended, but not every customer has this information. If it is unavailable, provide the pipe material, diameter, standard or pipe specification first.
What if I do not know the actual flow rate?
Provide the expected minimum, normal and maximum flow if possible. If the flow is determined by a pump, dosing system or process equipment, provide the equipment information as well.
Can I select the sensor based only on pipe diameter?
Not reliably. Pipe diameter is important, but material, wall thickness, liquid and operating conditions also affect ultrasonic measurement.
Do I need to remove all pipe insulation?
Normally, no. For a typical clamp-on installation, only the insulation around the sensor mounting area needs to be removed so the sensors can contact the pipe wall directly.
Can a supplier select the flow meter from a pipeline photo?
A photo is useful for understanding the installation, but it is usually not enough by itself. Combining the photo with pipe size, material, liquid and flow information makes the technical review much more reliable.