Ultrasonic Liquid Level Indicator

The Portalevel® Mini is a portable and battery powered, liquid level indicator designed to non-invasively, accurately, and reliably measure the level of fire suppression agent contained within a cylinder. The Portalevel® Mini is suitable for most standard size cylinders containing CO2, Liquified Clean Agents and Halons. 

Get help buying? Chat now, email or call +44 207 629 8475


The Portalevel® Mini provides an ideal solution for testing typical fire suppression cylinders. It utilises our trusted 7th generation technology, providing a very versatile and reliable solution. Over the years it has undergone numerous upgrade programs and the most popular unit in the range for testing standard size fire suppression cylinders. 

The Portalevel® Mini is particularly advantageous for fire servicing companies and asset owners managing their own fire suppression systems. This is because the Portalevel® Mini provides a very quick, safe and efficient method for testing fire cylinder contents. Traditionally, companies manually weigh cylinders in order to measure cylinder content, which is dangerous, time consuming and requires shutdown of the fire suppression system.  

  • User-friendly, versatile and accurate to ±1.5 mm. 
  • Calibration feature and additional power setting for increased gain. 
  • Low-cost model.  
  • Capable of testing a wide variety of fire suppression agents, such as; CO2, FM200™, NOVEC™ 1230, old Halon agents, FE-13™, FE-25™, NAF S III™ and most core Clean Agent systems. 


The Portalevel® Mini is designed to be a portable way to non-invasively locate the liquid level inside most single skinned cylinder. Our technology is suitable for many applications, but it is most widely used as a replacement to both weighing fire suppression cylinders during installation and servicing, or replacement for the fitting of internal and invasive liquid level ‘float’ devices. Once the liquid level height inside a container has been located, the agent weight can be determined using the Portasteele® Calculator, which is designed to quickly convert liquid height to agent weight accounting for the cylinder size, agent type and temperature.  


Converting Liquid Level to Weight: Monitoring the liquid level in fire cylinders is a vital aspect of any fire suppression system maintenance schedule, however, understanding how the liquid level relates to the fill weight of the cylinder is equally important. Coltraco Ultrasonics offer, in conjunction with the Portalevel® range, the world’s first liquid level to agent mass calculator.  


The Portasteele® Calculator calculates the agent weight of a fire suppression cylinder. It does this by using the liquid level determined by our Portalevel® range or inversely, by using the required fill level for a certain weight of suppression agent. The Portasteele® Calculator is sold as a stand-alone unit on a 7’’ hand-held tablet to be used in conjunction with our Portalevel® range.  



Operating Principle 


  • An ultrasonic transducer, coated in ultrasound gel (or water) generates an ultrasonic pulse that is transmitted into the fire cylinder and is reflected back. The ultrasonic gel acts a couplant by removing any air gaps between the ultrasonic transmitter and the cylinder wall, thus allowing the transmission of ultrasound.  
  • As the wave travels throughout the cylinder, some of its energy is dissipated into the cylinder and its contents. This results in the signal returned to the transducer having decreased amplitude. Analysis of the returned signal can be used to determine if the transducer has been placed in the liquid or gas phase.  
  • The Portalevel® Mini’s display, using a numerical value indicates what phase the ultrasonic transducer is placed in.  
  • The device is calibrated by moving the transducer up and down the cylinder whilst reading the numerical value off the display and engaging the ‘CAL’ button when in the appropriate section.  

What's in the box

Portalevel® Mini Unit: main electronic unit fitted with harness points for handsfree operation.  

Handheld Ultrasonic Sensor: fitted with magnetic head to ensure perfect positioning on the cylinder wall every time. 

Ultrasonic Gel: ensures perfect connection between cylinder and sensor allowing the transfer of ultrasound into the inspection surface.  

Carrying Case: robust protective case which isideal for transportation, storage and protection in harsh environments. 

Infrared Thermometer: used to measure cylinder surface temperature.  

Calibration Certificate: providing traceability of accuracy and documenting unit setup.  

Operating Instructions: manual provides setup instructions and step-by-step guide for usage. Technical support is available for the lifetime of the product.  

Techical specifications


  • 200mm x 93mm x 45mm
  • 420g


+/- 1.5 mm / +/-1/16 inch 


14mm diameter magnetically mounted sensor applicator with a 1 m BNC coaxial cable. 

Power supply

4 x AA 1.5V batteries

Approximately 10 hours battery life during normal operation 



Temperature range

-10C to +70C

Humidity range of 5% to 95%


  • Main unit – 3 Year Warranty 
  • Sensor –  1 Year Warranty 
  • Technical Support – Lifetime of the unit


Download Portalevel Mini Brochure

For basic product informatin, please find below. If you have any other questions, please contact us directly.

Frequently asked questions

What agents can the Portalevel® Mini measure?

The Portalevel® Mini can measure the level of a wide variety of liquids. The primary application is for checking the liquid level in fire suppression cylinders. These agents commonly include:CO2,FM200™ (standard size cylinders),NOVEC™ 1230 (standard size cylinders),Halon agents,FE-13™, FE-25™,NAF S III™ and,most core Clean Agent systems.

How accurate is the Portalevel® Mini?

The Portalevel® Mini can identify the liquid level to ±1.5 mm of the actual liquid level. When using the Portasteele® Calculator to convert the liquid level to agent weight, the results are accurate to within 1%.

What cylinders can the Portalevel® Mini measure?

The Portalevel® Mini is very versatile and works on a large range of cylinder sizes. We have an extensive range of products that can measure anything from 10 cm to over 15 m diameter, so get in touch to find out which unit is suitable for your application.

Do I need specific ultrasonic gel?

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.

Can I use the Portalevel® Mini on CO2 above 31°C?

No, unfortunately above this temperature CO2 converts to a gas and your cylinder will no longer have a liquid level to measure. We recommend testing CO2 in lower temperatures. Please, get in touch if you need recommendations for hot climate CO2 monitoring.

Will high temperatures affect other fire suppression agents, such as Clean Agents?

Yes, however, these agents are far more stable at higher temperatures that CO2, and although the liquid level will naturally rise with increased temperature it is far less than with CO2 and, therefore, can still be tested.

My cylinder has a siphon tube inside, can I still use the Portalevel® Mini?

Yes, this unit is specifically designed to work despite the presence of a siphon tube. 

Related Products

Join Our Journey

British manufacturer of ultrasonic technologies, exporting to 120 countries and winners of The Queen’s Award 2019.

©Copyright 2021 Coltraco Ltd. All rights reserved.