Ultrasonic Thickness Gauge Range

Welcome to Coltraco Ultrasonics’ range of Ultrasonic Thickness Gauges. 

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

Our Ultrasonic Thickness Gauge range has been tested and calibrated according to BS EN 15317:2013 standards on a calibrated carbon steel block that is manufactured to EN ISO 2400:2012 and ISO 7963:2006 standards. 

Our ultrasonic thickness gauge range are widely used in non destructive testing and has an accuracy of +/- 0.1mm.  

Our multi-echo ultrasonic thickness gauges are capable of ignoring paint layers up to 20mm thick. 

Why choose Coltraco Ultrasonics’ range of Ultrasonic Thickness Gauges 

Accurate and reliable to meet BS EN 15317:2013 which is the standard for ultrasonic testing, characterisation and verification of ultrasonic thickness measuring equipment  

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 

Our multi-echo range is able to ignore paint coatings up to 20mm in thickness, giving you the material’s true thickness readings accurate to +/- 0.1mm 

On our latest innovation, the Portagauge® 5, we have included A-scan and oscilloscope trace functionality to assist your measurements, observing material condition and help verify correct return backwall echo to give you confidence that you are measuring the correct wall thickness  

We have tried and tested a large number of different materials, including various metals and hard plastics, and have created a built-in database in our Portagauge® 5 containing speed of sound data of 12+ different materials pre-loaded in the unit for convenience which also includes an option to enter custom materials 

For marine applications, it meets Classification Society requirements for marine thickness gauge measurement equipment and has an LCD backlight to allow working in dark, poor visibility spaces 

Technical support and advice available throughout the lifetime of the unit and we are here to help you with your application 

Multi-Echo Ultrasonic Thickness Gauge Operating Principle

The principle of multi-echo ultrasonic thickness gauging using an ultrasonic multi-echo thickness measurement tool is simple and can be illustrated by the figure below. 

All sounds are physical vibrations which move through a material, and in the case of the sound we are used to, the vibrations move through air.  Ultrasound is the same as the sound we experience, but its frequency is beyond that which humans are capable of hearing. Whilst the highest frequency a human can hear is around 20,000 Hz, all Portagauge® units use sound at a frequency of 2.25 MHz, 2.5 MHz or 5 MHz depending on the specific probe being used. 

All Portagauge® devices use ultrasound to measure the thickness of a material.  The unit sends a strong electrical signal to the probe, causing it to emit a high energy pulse of ultrasound. The transmitted ultrasound pulse travels through both the coating and the metal and reflects from the back wall. The reflected sound waves then reverberates within the metal, with only a small portion of the echo travelling back through the coating each time. The timing between the small echoes gives the timing of the echoes within the metal, which relate to the metal thickness. The returned echoes need not be consecutive as the thickness gauge will interpret them automatically and calculate the thickness. A minimum of three echoes are checked for each pulse that is sent into the metal in order to qualify as a multi-echo ultrasonic thickness gauge. 

Types of Material measured by the Portagauge® range 

The Portagauge® range is capable of measuring the thicknesses of various metals and hard plastics. There are different ultrasonic sensor options with different frequencies available to cope with different materials. 

On the Portagauge® 5, there is a database containing speed of sound data of 12+ different materials pre-loaded in the unit for convenience. Example materials in the database are: carbon steel, stainless steel 304, stainless steel 316, cast iron, ductile iron, copper, PVC, lead, nylon, polyethylene, aluminimum, asbestos and fibre glass. There is also an input for custom materials, to allow you to input test material not in the list. 

If there is a particular material that you are looking to test but are unsure if our Portagauge® range can do it, please get in touch with us by submitting an enquiry. 

Key Measurement Considerations 

We are aware that our customers are engaged in non-destructive testing using ultrasonic thickness gauges for measuring thicknesses of materials in a variety of different conditions. We have developed a list of best practice recommendations, to ensure you have the knowledge required to take a successful measurement. 

Please remove any surface debris that may interfere with the measurement 

For poor condition materials, typically badly corroded metals, please ensure sufficient ultrasonic gel is applied on the surface of the material as this will ensure all air pockets between the sensor and material will be eliminated. Air pockets will affect the ultrasound signal, reducing the reliability of the measurements obtained 

Please ensure sufficient pressure is applied to the sensor when performing the measurement 

There is no requirement to remove paint layer from the material when working with the Portagauge® 4 and Portagauge® 5 as the ultrasonic multi-echo technology will take into account the additional sound reflection and identify the correct return echo that represents the true wall thickness of the material  

How does the Portagauge® range work to detect corrosion? 

Our Portagauge® 3 and Portagauge® 5 uses dual element sensors which are commonly used for corrosion inspection work. They are highly sensitive to detecting corrosion in the form of pitting corrosion and just about any other forms of corrosion. Pitting corrosion in particular is a localised form of corrosion by which cavities are produced in the material and can be damaging to the material. 

Dual element sensors contain two piezoelectric crystals, one acting as an ultrasonic transmitter and the other as an ultrasonic receiver. The dual element set up gives the sensors an advantage over single element sensors when dealing with irregular surfaces in highly corroded materials, due to the pseudo focusing effect the ultrasound beams have. This allows the dual element sensors to be more sensitive to echoes from the base of the pits of the corroded material, which represent the minimum remaining wall thickness. The reflected sound waves from the portion of the good material will give an indication of how badly the material has been corroded. 

The wall thickness measurement that is displayed on the Portagauge® range represents the remaining wall thickness of the material that is in good condition. By comparing the wall thickness measurement from the Portagauge® to the actual wall thickness of the material when it was in brand new condition allows the operator to determine the severity of the corrosion. 

Advantages of a Multi-Echo Ultrasonic Thickness Gauge over a Single-Echo Ultrasonic Thickness Gauge 

The Portagauge® 3 utilises the single-echo technology which detects the amount of time taken for a single echo of reflected sound to travel through the material and back to the sensor. The time it takes to travel through the material, along with the speed of sound of the material allows the device to calculate the wall thickness. 

The Portagauge® 4 and Portagauge® 5 utilises the multi-echo technology whereby the transmitted ultrasound pulse travels through both the coating and the metal and reflects from the back wall. The reflected sound waves reverberates within the material, and only a small portion of the echo travels back through the coating each time. The timing between the small echoes gives the timing of the echoes within the metal, which relate to the metal thickness. A minimum of three echoes are checked for each pulse that is sent into the material in order to qualify as multi-echo ultrasonic thickness gauging technology. 

For the marine industry, various Classification Society standards require only multi-echo ultrasonic thickness gauges to be used. We recommend the Portagauge® 5 for such applications. Examples of such standards are found below: 

IACS: Specific requirements from IACS Procedural Requirements PR No. 19 and No.77 

DNVGL: DNVGL-CG-028 – Section 3 – Basic Requirements 
5) Only multiple echo instruments may be used for TM onboard all ships 

Do the Portagauge® range of ultrasonic thickness gauges work as paint depth gauges, a paint thickness gauge or a paint tester? 

The Portagauge® range of ultrasonic thickness gauges measures the wall thicknesses of various metals and hard plastics. The multi-echo technology of the Portagauge® 4 and Portagauge® 5 is designed to ignore the paint coatings of the material, allowing the material’s true thickness to be measured. As a result, the Portagauge® range is not suitable to be used as paint depth gauges, a paint thickness gauge or a paint tester. 

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