Ultrasonic Liquid Level Indicator for Pipes

The Portapipe® is a portable and battery powered liquid level indicator designed to non-invasively, accurately, and reliably measure the liquid level within pipes and small cylinders.

Type – Ultrasonic Liquid Level Indicator for Pipes

Part Number – 3174740-PIPE

Fluid Types – It has a built-in database which includes commonly used fluids such as Water (at 10°C, 20°C or 30°C), Sea Water, Diesel, Petrol, Fuel Oil, LPG, Ethanol, FK-5-1-12, Freon R134A, Freon R22, HFC-227ea, Methanol, FM200™, NOVEC™ 1230 and many more. Add any fluid simply by inputting its speed of sound.

Pipe Materials – Features a built-in database of commonly used pipe materials, including carbon steel, copper, PVC, and fibreglass, along with their respective sound speeds. Add any custom material type simply by inputting its speed of sound.

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Ultrasonic Liquid Level Indicator for Pipes

Coltraco Ultrasonics’ newest liquid level indicator, the Portapipe®, is a highly precise, multi-faceted non-invasive, pulse-echo liquid level indicator. With two distinct mechanisms for liquid level detection and measuring, the Portapipe® is an all-in-one tool for identifying the liquid level in horizontal or vertical pipes, cylinders or other containers from a minimum size of 25mm (1″) to a maximum size of 331 mm (13”) diameter.

  • User-friendly, versatile, and accurate to ±1% of the true level.
  • Time-of-flight and absence/presence liquid level measurement capabilities.
  • Automatic or manually adjustable gain.
  • Predictive search for reflections within an expected return time window.
  • Capable of testing a wide variety of fluid types, including water, diesel, petrol, FM200™, NOVEC™ 1230 and many more.
  • Test a custom fluid (not included in preloaded database) by simply selecting “Other” and entering the speed of sound.


With its combined time-of-flight measurement and absence/presence detection capabilities, the Portapipe® provides simple, precise and reliable measurements of liquid levels in both horizontal and vertical pipes, making it an invaluable tool for a wide range of applications and industries.

Time-of-flight measurements are ideal for horizontal pipes, where ultrasonic pulses are transmitted from the bottom of the pipe through to the surface of the liquid. When the pulse reaches the surface, it is reflected to the sensor. The time that this takes is precisely measured by the device before being converted into an accurate reading of the exact height of the liquid in the pipe. This value is displayed on the screen as a “percentage fullness” based on the diameter of the pipe.

For identifying the exact transition between liquid and gas in vertical pipes, however, the absence/presence method will allow you to do this consistently, reliably and with ease. Simply enter the information of the pipe and fluid into the device and begin scanning the length of the pipe with the sensor. When the sensor is placed below the liquid, the ultrasonic pulse will be transmitted through the liquid to the far wall of the container and will then be reflected back to the sensor. Therefore, below the liquid level, the device will consistently read 100% full and the black bar indicator will be full. Above the level, however, the pulse will not be transmitted beyond the near wall of the pipe, and so the percentage value will fluctuate and the black bar indicator will be empty. The liquid level is therefore the point at which the bar indicator changes from full to empty or vice-versa.

Trust the Portapipe® to deliver unparalleled accuracy, reliability, and efficiency for your pipe liquid level measurement needs.

Operating Principle (Horizontal Pipes)

  • An ultrasonic transducer, coated in ultrasound gel (or water) generates an ultrasonic pulse that is transmitted into the pipe or cylinder and is reflected back to the sensor from the surface of the liquid. The ultrasonic gel acts a couplant by removing any air gaps between the ultrasonic transmitter and the container wall, thus allowing the transmission of ultrasound.
  • The time-of-flight for the pulse is measured precisely and used, along with the fluid speed of sound, to precisely calculate the liquid level. This value is then converted into a percentage value of the pipe diameter and displayed digitally on the screen.
  • By entering the container wall thickness and material, the device is also able to calculate the length of time the pulse spends in the walls of the container and adjust the in-liquid time of flight accordingly for maximum precision and accuracy.


Operating Principle (Vertical Pipes)

  • As for horizontal pipes, the ultrasonic transducer generates and transmits ultrasonic pulses into the container and ultrasonic gel (or water) is used as a couplant.
  • For vertical pipes, rather than measuring the level directly using time-of-flight, the level is located using an “absence/presence” method, physically moving the sensor.
  • Where liquid is present in the container, the ultrasonic pulse will be transmitted through the liquid, reflect from the far wall and be received some time later on the sensor. Above the liquid level, however, the pulse cannot be transmitted beyond the cylinder wall and so no reflection is detected. For a vertical pipe, below the liquid level the detected reflection should always indicate a 100% full pipe, whereas above the liquid level, the value will fluctuate.
  • This allows you to determine whether the sensor is below the liquid level or not. Therefore, by moving the sensor up/down the walls of the container, the liquid level can be identified, as the exact point at which the reflection appears or disappears.


Note: although the recommended procedure for horizontal pipes is to use the time-of-flight method, it is also possible to locate the liquid level by monitoring the oscilloscope trace as the sensor is moved circumferentially around the cylinder from bottom to top and finding the point at which no reflection is detected. The position of the reflection (or percentage fullness) does not matter if this procedure is used.


What's In The Box

  1 x Portapipe® Main Unit: Main electronic unit
  1 x 2.5 MHz Dual Element Ultrasonic Sensor: Sensor for pipes 100mm (2”) – 331mm (13”)
  1 x 5.0 MHz Dual Element Ultrasonic Sensor: Sensor for pipes 25mm (1/2”) – 100mm (4”)
  1 x Ultrasonic Couplant: Ensures perfect connection between cylinder and sensor allowing the transfer of ultrasound into the inspection surface.
  1 x Robust Carrying Case: Robust protective case which is ideal for transportation, storage, and protection in harsh environments.
  1 x User Manual: Manual provides setup instructions and step-by-step guide for usage. Technical support is available for the lifetime of the product.
  1 x Calibration Certificate: Providing traceability of accuracy and documenting unit setup.

Technical specifications

Technical Specification
  • Height: 168mm
  • Width: 82mm
  • Depth: 31mm
  • Weight: 300g

10.0mm – 331.0mm (0.39” – 13“)


Most fluids can be measured, built-in database contains the following: Water (at 10°C, 20 or 30), Sea Water, Diesel, Petrol, Fuel Oil, LPG, Ethanol, FK-5-1-12, Freon R134A, Freon R22, HFC-227ea, Methanol

If you are testing a fluid that is not included in the database, select “Other” and enter the fluid speed of sound.


± 1% of true level


Metric (mm) and Imperial (inches)


Time-of-flight: Measures the time of flight for an echo of an ultrasonic pulse from the surface of the fluid and use speed of sound to calculate distance (for horizontal pipes)

Absence/presence: Determine whether liquid is present or not, based on whether a consistent reflection is identified (for vertical pipes)


2.5 MHz, 5.0 MHz


Full 128 x 68-pixel graphics with backlight for working in poor visibility conditions

  • Custom fluid sound velocity input enables users to test custom fluids
  • Oscilloscope trace to assist in performing a good measurement and to verify correct backwall/ fluid surface echo
  • Bar indicator for absence/ presence method.

9V PP3 battery, up to 12 hours continuous use with auto shutdown after 30 seconds of inactivity


IP 65 enclosure


Dual element with 0.9m LEMO-00 cable

  • 2.5 MHz – 14mm diameter sensor
  • 5.0 MHz – 10mm diameter sensor
  • 5.0 MHz – 6mm diameter sensor
  • CE
  • Coltraco is ISO 9001:2015 and ISO 14001 approved
  • Main unit – 3 Year Warranty
  • Sensor –  1 Year Warranty
  • Technical Support – Lifetime of the unit

See the Portapipe® in action.

Frequently asked questions

In principle, the Portapipe® can be used on any liquid, however, practically, the acoustic properties of certain liquids can make measurements impractical or impossible. In particular, liquids that are very highly attenuative to ultrasound may not allow the signal to be detected. However, for the majority of applications this is not an issue. The fluid types built into the device include, but are not limited to: •Water •Diesel •Petrol •FM200™ •NOVEC™ 1230 However, if the fluid you wish to measure is not listed, you may simply select “Other” and enter the fluid speed of sound.
The Portapipe® can measure the liquid level in vertical or horizontal pipes very precisely, to within 1% of the true liquid level.
The Portapipe® is designed primarily for pipes or small cylinders. The maximum diameter of container that can be measured is 331 mm (13 in). The minimum diameter of container is 10 mm (0.39 in). The maximum diameter can also be affected by fluid type. Fluids with very low sound speeds (e.g., NOVEC™ 1230) may substantially limit the maximum measurable diameter.
No, you can use any ultrasonic gel, available in most pharmacies, as well as petroleum jelly. Water will also work, but in hot environment needs very regular application.
The time-of-flight method for liquid level measurement will only work if the container being tested has no obstructions, or at least, there is an unobstructed path available for the signal. The absence/presence method for vertical or horizontal pipes will still work even with an obstruction in the container, however, this will affect the positions of the reflections when below the liquid level.
The Portapipe® has a built-in database of 13 pipe materials along with sound speeds, including (but not limited to) carbon steel, copper, PVC and fibreglass. If your pipe material is not listed, you may define a custom material by selecting “Other” and defining the speed of sound of the material under the “Vessel SOS” setting. Please note that it is unlikely that the Portapipe® will work on concrete or lined pipes.

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