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.