Ultrasonic Flow Meter

Welcome to Coltraco Ultrasonics’ range of Ultrasonic Flow Meters. 

We pride ourselves with the quality, reliability and accuracy of our instruments – all made in the UK. 

Our Ultrasonic Flow Meter range has been tested and calibrated at an ISO 17025 laboratory, meeting accuracies of +/- 0.5% of the true flow rate. 

Using non-invasive technology, our transit time flow meters have significant advantages against an inline flow meter by reducing installation cost, risk and downtime for your flow rate measurements.  

The Portasonic® PRO is a handheld tablet-based ultrasonic clamp-on flow meter with pressure prediction software for calculating internal pipe pressure from measured flow rates. It combines the functionality of the Portasonic® 2.FL0 in measuring flow rates non-invasively with the Portasonic® CALCULATOR, to form the first instrument capable of calculating the internal pressure within pipes, using non-invasive, externally measured flow sensors.

P/N: 2618949-PSOPRO

The Permaflow® is a fixed, clamp-on, ultrasonic transit time flow and heat meter that is non-invasive for measuring the flow rates of liquids containing less than 10% of gas/solid contents. It is mains powered, designed for 24/7 monitoring and is accurate to +/- 0.5% of measured value under ideal conditions.

P/N: 3578010-FLOW

Calculate internal pipe pressures using externalnon-invasive and portable flow sensors. To be used alongside the Portasonic 2.FLO® portable ultrasonic flow meter 

P/N: 2618949-CALC


The Portasonic® 2.FL0 is a handheld, clamp on, non-invasive ultrasonic transit-time flowmeter designed to measure flow rates liquids in pipes accurate to +/- 0.5% without requiring any invasive installation. It works on a wide range of liquid types containing less than 10% solid content, and pipes from DN15 – DN2500 made from different metal or plastic materials.

P/N: 2618949-PSO

Why choose Coltraco Ultrasonics’ range of Doppler Ultrasonic Flow Meters?

  1. Accuracy and reliability proven at an ISO 17025 certified laboratory for flow measurement devices in the UK

  2. We strive to offer the highest quality instruments, built with exceptional quality materials in the UK and remain competitively priced in the market worldwide through our unique R&D position
  3. Our ultrasonic flow sensors are made using a special composite material to optimise ultrasound transmission
  4. All units come with built-in oscilloscope for signal diagnostics that assists you in performing a reliable measurement as part of the setting up process
  5. Modular I/O options for the Permaflow® system which allows you to choose only what you need, saving cost and money
  6. Integrated ultrasonic thickness gauge on the Portasonic® 2.FL0 which allows you to perform simple NDT testing (ultrasonic thickness gauging) on the wall thickness of your pipe to determine wall thickness and look for signs of corrosion
  7. Technical support and advice available throughout the lifetime of the unit and we are here to help you with your application 

Transit Time Ultrasonic Flow Meter Operating Principle

The principle of flow measurement using ultrasonic clamp-on transit time measurement is simple and can be illustrated by the figure below.

ultrasonic flow meter drawing
Flow velocity drawing

Two ultrasonic sensors are clamped to the outside of the pipe at a pre-determined distance apart. Ultrasonic signal travels between the transmitters through the pipe wall and the fluid within the pipe. If the fluid is flowing, then it takes slightly longer for the ultrasound to travel against the flow (upstream time T_up) than with the flow (downstream time T_down).

In a typical installation, the individual times measured upstream and downstream are just a few hundred microseconds, the difference between them is typically measured in tens of nanoseconds.

This very small time difference (T_up – T_down) is measured by the flowmeter and is directly proportional to the flow velocity (V) of the fluid.

Types of Flow Measured by Portasonic® 2.FL0 and Permaflow®

Volumetric Flow Rate: Knowing the pipe internal cross-sectional area the ultrasonic flow meter can calculate volume flow rate in many common engineering units such as litres per hour (l/h), gallons per minute (gpm) etc. This gives a similar measurement unit to that given by a vortex flow meter, variable area flow meter, differential pressure flow meters or other inline flow meter.

Mass Flow Rate: Incorporating the density of the fluid allows the ultrasonic meters to calculate mass flow rate. This gives a similar measurement unit to that given by mass flow meters or coriolis meter.

Heat or Energy Flow Rate: A knowledge of inlet and outlet fluid temperature and Specific heat Capacity of the fluid allows the flow meter to calculate heat flow rate. This is suitable for energy efficiency calculations for heating and chilling applications.

Totalised Flow: Both the Portasonic® 2.FL0 and Permaflow® come with a flow totalizer function. The flow totalizer totalises (add up) the volume of fluid that has flowed through the pipe. The totalizer function allows these rates (Volumetric Flow Rate, Mass Flow Rate, Heat or Energy Flow Rate) to be totalled and positive, negative and net values can be displayed.

Key Doppler Flow Meters Installation Considerations

  1. Ensure the pipe is full of fluid and that air bubbles in the fluid are minimised to ensure the ultrasound signal transmits effectively
  2. Ensure sufficient distance between the ultrasonic sensors and the nearest bend or valve in the pipework to minimise turbulence
  3. Ensure the fluid has less than 10% solids content, if the fluid exceeds this limit then a Doppler flow meter may be more suitable

Advantages of an Ultrasonic Flow Meter against an Inline Flow Meter

  1. No installation costs such as drilling into pipes, therefore no downtime to the pipe network is present
  2. As there is no contact with the fluid being measured, there is no risk of pressure drop throughout your pipe network
  3. As the fluid cannot damage the flowmeter, this could contribute to a longer lifespan and lower maintenance cost compared to inline flow meters which are in contact with the fluid and risk being damaged by the pressurised flowing fluid

The Importance of Calibration in Flow Meters

Performing calibration of flow meters is the only way to ensure the flow measurement performed by your ultrasonic flowmeter is accurate. Calibrated flow meters operate to give you the confidence that your ultrasonic flight flow meters will produce a reliable measurement.

At Coltraco Ultrasonics, our ultrasonic flow meter range has been tested and accuracy proven at an ISO 17025 certified laboratory for flow measurement in the UK.

Using non-invasive ultrasonic flow meter to determine pressure

Coltraco Ultrasonics has developed the Portasonic® Calculator which is the first instrument capable of determining the internal pressure within pipes, using non-invasive, external flow measurement technology.

This Portasonic® Calculator is designed to operate alongside our Portasonic® 2.FL0 Ultrasonic Flow Meter. The Portasonic is one of the world’s leading non-invasive flow meters and is an essential tool for a wide variety of maintenance and inspection needs

The Portasonic® Calculator is designed as a supporting instrument and uses an empirical equation derived from the laws of fluid dynamics to calculate the liquid pressure to within 5% accuracy.

Our knowledge of the properties of 19+ different fluids and 23 different common pipe materials has enabled us to acquire a detailed understanding of the pressure required to drive different fluids at a variety of flow speeds.

Suitability of an ultrasonic flow meter for water flow metering

Water meters are used all throughout domestic and commercial environments to track water usage. Transit time ultrasonic flow meters are highly capable of performing accurate and reliable water measurement in pipes. While water meter users typically go for low-cost instruments, ultrasonic flow meters are the most appropriate solution for situations where the pipe cannot be drilled into or if the flow of water cannot be interrupted while the water meter is being fitted. The non-invasive principle of a transit time ultrasonic flow clamp on meter is highly beneficial for such situations whereby an inline flow meter cannot be used. Water is one of the easiest liquids to measure due to its physical and chemical properties and you should have no problems with using ultrasonic flowmeters as water meters.

Portasonic® 2.FL0 and Permaflow® Technology Comparison

  1. Is the ultrasonic technology used in Portasonic® 2.FL0 and Permaflow® similar to the ultrasonic technology used for natural gas flow metering and flow meter for gas?

The ultrasonic technology used in flow meter for gas or flow meter for air is not applicable to our range of ultrasonic flowmeters. Our ultrasonic flow meters are designed for flow measurement of fluids.

  1. In ultrasonic flow meter technology, what are the main differences between transit time flow meters and doppler flow meters in measuring volume flow rate?

Transit time flow meters uses two clamp on ultrasonic sensors spaced at a pre-determined distance, one as an ultrasonic transmitter and another as an ultrasonic receiver. Ultrasonic signal travels between the ultrasonic sensors through the pipe wall and the fluid within the pipe. If the fluid is flowing, it takes slightly longer for the ultrasound to travel against the flow than with the flow. The time difference between upstream and downstream is measured and is directly proportional to the fluid velocity.

Doppler flow meters on the other hand, rely on bubbles and particles in fluids which are suspended to reflect the ultrasonic signal that provides a shift in the frequency. The shift in frequency is directly linked to the velocity of the travelling fluid. By measuring the frequency shift between the ultrasonic transmitter, receiver and the fluid carrier (i.e. bubbles and particles), the fluid velocity is determined.

  1. What are the main differences between an ultrasonic flow meter and mechanical flow meters?

A mechanical flow meter is an inline flow meter. Examples are positive displacement flowmeters (PD meters) and turbine flow meters. An ultrasonic flow meter uses clamp on ultrasonic sensors which are non-invasive. Mechanical flow meters are typically built for a specific range of pipe size, and cannot be retrofitted into other pipe sizes whereas an ultrasonic flow meter works over a broad range of pipe sizes as it is non-invasive. The pressure of the pipework also has to be taken into account for a mechanical flow meter as this can damage the mechanical flow meter whereas this is not a point of concern for ultrasonic flow meters which are external, non-invasive and clamp on the pipe.

  1. How do the Portasonic® 2.FL0 and Permaflow® compare against inline flow meters for measuring mass flow?

An example of an inline flow meter for measuring mass flow is a Coriolis meter. The Coriolis flow meter is an invasive flow meter that require breaking into the pipe during installation. The mass flow measurement from a Coriolis meter is very reliable, however, the ultrasonic flow meter is capable of matching the mass flow measurement accuracy of the Coriolis meter under certain conditions. If you are looking for a non-invasive solution to measure mass flow, the Portasonic® 2.FL0 can assist with its clamp on ultrasonic transmitters that is capable of measuring mass flow.

  1. Can we distinguish between rotameter and ultrasonic flow meter?

A rotameter is a form of a variable area flow meter. It is a form of inline flow meter and is commonly used in different applications to ultrasonic flow meters.