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HI-FOG® water mist invention for fire fighting


October 23, 2019

HI-FOG water mist fire extinguishing system is Göran Sundholm’s innovation that is used for extinguishing fires by spraying high-pressure water mist in small droplets into the fire. The company founded by Sundholm, Marioff Oy, protected solutions related to the innovation with several patent applications worldwide.

Water is an excellent extinguishing agent: it is cheap and non-toxic, it is usually readily available, and it does not involve any environmental hazards. Water extinguishes fire most efficiently when it evaporates. Evaporated water binds large amounts of heat. In addition, evaporation dilutes oxygen content in the fire space, which restricts the burning rate and the fire may be suppressed completely. Inventor and entrepreneur Göran Sundholm from Tuusula realised in 1991 that the extinguishing properties of water can best be utilised when it is applied as water mist.

Sundholm developed HI-FOG, the high-pressure water mist extinguishing equipment, which became a success story and a viable competitor to conventional fire extinguishing systems.

The primary extinguishing mechanism of conventional sprinkler systems is watering the burning material and thereby, restricting the fire. However, they are ineffective: the system requires large amounts of water, and the pipelines of the fire extinguishing equipment are therefore large. In addition, water damage caused by fire extinguishing is usually extensive. In fires involving liquids, water is useless, and extinguishing foam, gas or powder must be used for extinguishing the fire.            

What is the HI-FOG system based on, Tapio Äkräs, Director of Patents at Kolster?

HI-FOG extinguishes fires by spraying high-pressure water mist in small droplets into the fire. The efficiency of the water mist is based on the simultaneous operation of three extinguishing mechanisms: cooling, the absorbing of thermal radiation and displacing oxygen. Microscopic droplets of water mist are formed when the system is activated and high-pressure pumps are initiated that pump water through special nozzles.

High pressure causes a high momentum for water droplets, so that the droplets penetrate into the fire thus cooling the burning material and its surroundings. Evaporated water does not only effectively bind thermal energy, but it also displaces oxygen locally when it expands. Further, the large number of small water droplets prevents the spread of heat radiation from the fire to the surroundings.

What are the competitive advantages of the HI-FOG water mist fire protection equipment?

The innovation proved to be a success. At first, the water mist fire extinguishing system took over the fire protection market of cruise ships and merchant vessels. Later, deliveries expanded to include trains, tunnels, data centres, power plants and hospitals.

Water mist is an environmentally friendly and safe fire extinguishing mechanism. Efficient water mist extinguishing equipment can replace extinguishing foam, sprinkler and gas systems. HI-FOG uses considerably less water compared to conventional sprinkler systems and it can protect locations where it has not previously been possible or sensible to use a water-based fire extinguishing system. Such areas typically contain electronics, electrical appliances or combustible liquids.

How did the patenting of HI-FOG get started?

The most important part of the water spraying system was the specially designed spray head to which Göran Sundholm's first patent applications were related.

HI-FOG-vesisumusammutuslaitteiston toimintaperiaate

The operating principle of the HI-FOG water mist fire extinguishing equipment: FI patent no. 100947. │Main image of the article: Marioff Corporation Oy

The patent FI100947 contains a spray head (1) with four downward-facing nozzles (3) at an angle of around 45 degrees and a nozzle (4) in the middle of the spray head that points directly downward. When liquid at a sufficiently high pressure (100 bar) is fed into the inlet (5), a spindle (8) moves downwards and liquid can flow through the spindle’s (8) boring (9) to the central nozzle (4) and through the annular space (12) surrounding the spindle and drillings (7) to side nozzles (3).

The pressure of the liquid causes a rotator (22) to rotate so that there is a strong vortex in the liquid that is in the space (21) in front of the nozzle (20) outlet (33). The nozzle (20) then sprays the liquid as mist consisting of small droplets that are directed at a sufficient speed to the fire. By placing the middle and side nozzles close to each other, the mist formation of individual nozzles is focused as a directed spray.

Is it worthwhile to actively protect intellectual property rights?

The company founded by Sundholm, Marioff Oy, protected various solutions related to the innovation with a multitude of patent applications globally. The company has been exemplarily active in protecting its intellectual property rights, and patenting is certainly one of Marioff Oy’s strengths in intense international competition. Marioff is now part of the American United Technologies Group.

Since 1991, Marioff Oy has filed some 900 patent applications as well as some design and utility model registrations. Naturally, the 20-year protection period for early applications has already expired, but the company still has hundreds of active patents and patent applications.

Marioff markets the water mist fire extinguishing system under the brand name HI-FOG®, which is protected by trademark registrations.

To celebrate Kolster’s 145th jubilee year, we feature each month an interesting Finnish invention or patent.

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Azipod® thruster – a pioneer in the marine industry

ALD technology – an invention in the pocket of every Finn

Kohonen map – enabler of self-learning artificial intelligence

AIV fodder – the cream of the crop of Finnish inventions

The sauna stove – Evolution from a pile of rocks to a designer product

Heteka - an iron bed that became a bestseller of its day

Kolster’s first patent served the paper industry

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Tapio Äkräs
+358 50 524 2406