Fire in potato shed. pic2021@DamianRuitenga.
Investigating the new sprout inhibitors was an important part in the development of the Nebulizer* pic2021@studiolab
Here the Nebulizer* on HINT, during the test in the WUR laboratory. picsservatech@2022wur.lab.

About Sluys Techniek and Servatech BV

Dingeman van der Sluys, who has been active in technology for over 35 years, specializes in finding solutions to technical issues with his company Sluys Techniek. In particular with installations and machines. His international customers ask him for a diagnosis, technical advice or, on site, to repair a machine or control unit. He uses his experience and, if possible, the most modern electronics to repair complex machines. Together with his ability to improvise, he comes up with solutions for technical failures worldwide. 

 Accumulated experience gives confidence. Do what is promised. A deal is a deal. Usually it works. And sometimes it doesn't work. But always with attention to sustainability and safety.

The development of the Nebulizer is the result of technical problems due to a change in legislation. The European Food Safety Authority, EFSA, was active in mid-2019 to change the legislation on the use of a widely used sprout inhibitor Chlorpropham, or CIPC. A ban on its use was announced, but it would take until April 2021, before it really got that far. Several manufacturers were already active in developing a replacement for the product, but no replacement for the equipment used.

In the current year 2022, there are 3 to 4 products available, and they have a place in the market of germ inhibitors. These very expensive resources have such specific product properties that their use is not justified with the existing equipment without modifications. During the change of the drug, Sluys Techniek carried out several tests with different equipment, during which irresponsible major risks were identified. As an example, we cite tests with the equipment in combination with the new product, which resulted in a flash fire of up to 12 meters in length. It was immediately the end of this test, after which we made another test set-up outside the workshop. Despite precautionary measures, that outdoor test was also negative, the flame was again at least 12 meters. The temperatures were too high for these agents. In other cases, the pressure in the repository was too high and much valuable resource escaped as a result. The released odor clouds were clearly perceptible outside the barn…. It was a clear fact for Sluys Techniek. These new resources cannot be used with the existing equipment without modifications. In modern and well-insulated potato sheds it is certainly not inconceivable that during application, the pressure rises so high that an explosion occurs, whereby the damage cannot be foreseen. A spark in a switch box is enough.

There were and are reports in the press of large fires in storage sheds, also in Germany, Belgium and France. One only has to Google 'fire potato shed' or 'fire potato shed' to type in frightening results. 

Then Sluys Techniek decided to do things differently, as the son of an arable farmer, he had learned the tricks of preserving potatoes from his father. Believing there must be another option, he began to consult with the farmers in the area. He examined the building construction and electrical installation of various sheds and the available ventilation capacity. In order to use the new resources, a clear picture of the current repositories had to be obtained. Certain technical details, such as the location of the control cabinets, are important to possibly provide with overpressure in order to exclude the risk of fire. In this way the design of the new machine began. He rents out his own Tolsma barn to a farmer in the area, so he is also busy with the storage of potatoes every season. It is an art in itself, after the harvest in September, the potatoes are wheeled into the shed and the work begins. The most optimal temperature, the right humidity. To achieve this with the fluctuating outside temperature, the interplay of internal or external ventilation is a true art.

The potato consists of water for 80%, and is therefore very sensitive to storage for a long time, sometimes up to 8 months. That is also the reason to use the so-called sprout inhibition agents, which must be applied very accurately. In addition, the price of the new resources is so high that the degree of efficiency must be maximum. The better the storage, the better the potato. Small deviations in color and taste have major consequences. Therefore, the demands on the equipment are high, safety, accuracy and reliability are a necessity. The potato in all its manifestations is third on the list of the most eaten food in the world, after grain and rice.

For example, Sluys Techniek started drawing, constructing and using his contacts with arable farmers in the area in January 2020. What is the experience and how can it be improved, building each new element first, testing it, and taking it apart again. What weight is still acceptable, how small can it be made, and is it all together not too big to transport. The noise level had to be pleasant, the power consumption as low as possible, the heating sufficient. Do not use additional air, only the agent with the correct pressure, to avoid losses. The various components such as pipes and seals were also tested separately for properties in combination with the agents. The different flash points, temperature, volatility, there should be no combustion, because soot formation means loss of agent. For example, a seal had shrunk no less than 30% after 3 days in liquid, or a special rubber compound had become much too long due to another means. Every day, in the evening, sometimes through the night because something has to be finished for the test the next day. The building of the electronics is also a speciality in itself, the properties of the product, the regulations, the control and emergency provision, it is indispensable for the proper functioning of the machine. The importance of build quality, the materials used, the easy handling, even after many years of use. A prototype failed and had to be disassembled again, and so development went on, trying again and again. After 2 years of development, Servatech BV was added to establish contacts with organizations and companies. Meanwhile, the 21/22 storage season had started and the potato sheds had been filled. The real work had to begin. At 6 different storage locations in the area, 2 cm small openings were made, because it is important to keep the Nozzle IN the correct spot of the airflow. Only then can we make maximum use of the energy of the ventilation system. The entrained agent mixes with the air flow and thus reaches every place in the shed evenly. The farmers witnessed how the Nebulizer worked in their own barn, and were surprised by its compact size and pleasing sound. Due to the right combination of the agent, the nozzle and the applied pressure and temperature, the yield is easily adjustable. The maximum capacity of 30 liters per hour turned out to be more than sufficient in practice. The first storage season went well, the barns are empty again, and the farmers are satisfied with the use of the Nebulizer……

At the beginning of 2022, the CE mark was awarded, in accordance with the provisions in the Machinery Directive with the classification NEN/EN/ISO/IE. See p. specs.

A measurement was also carried out at WUR Wageningen, Agrosystem Plant Research, under the supervision of Dr. HJ Holterman. This concerns a measurement of the droplet spectrum in which 2 different laser beams are used to measure the droplets. See p. specs.