It is an object of the present invention to provide a low-temperature slot dryer using infrared waves, constructed from resistive infrared panels emitting long infrared beams, to be used in agriculture to dry grain, as well as to dry any small-grain materials, including those used in construction industry.

Patent description P. 215323 discloses a wood chip chamber dryer. In this solution, air flow is forced through a solar collector, slot space, sieve bottom due to suction power of an exhaust chimney generated by a significant difference in height between an air inlet in an inlet collector head and exhaust chimney air outlet. The dryer comprises a rotating head provided with a rudder adjusting the air flow thereto each time upwind, which improves air grasp needed for the wood chip drying. In proportion to the square of the wind speed, the dynamic air pressure triggers the drying air flow through small thickness layers of chips in boxes. It is significant that the small thickness of the air-blown layer results in lower air flow resistance and thus increases ventilation.

Utility model W.58894 discloses a dryer for loose material, particularly grain, in a form of an aerator and conveyor with an infeed and outfeed. It is characterised by that the aerator is an enclosed from the top vertical column provided in its lower zone with an air-inflow channel, which column walls and body walls form the conveyor, whereas the walls are provided with slots with covers shaped downwards and towards the conveyor space.

Polish patent description P.229669 discloses an apparatus for grain gelatinization, comprising a fluidising dryer provided at one end with an inlet opening fed with material from a dispenser, and at the other, opposite end a material reception neck, and inside the fluidising dryer mounted is a fluidising sieve with infrared heaters fixed thereabove. Additionally, a fluidising chamber is provided therewith.

Almost all traditional dryers that use heated air as a drying means and that are currently in use are convection dryers where the air transmits the heat onto the material being dried (raw material) and eliminates evaporated moisture. This drying method and the apparatuses using the method have certain disadvantages related to inefficient energy consumption. Such carried drying is inevitably accompanied by loss of heat absorbed by the apparatus itself and structure thereof, and external environment. It leads to overheating of the raw material and fails to reduce the original microflora. Summary of the above-mentioned problems only in relation to cereals and grains:

- raw material high drying costs due to significant energy costs;

- lack of versatile dryers on the market for a variety of grown cereals and pulses;

- inability to get good quality seed by farmers from their own grain and grain for milling industry (due to high temperature used when drying only forage is obtained);

- with raw material of high moisture, it is necessary to carry the drying process in several passes (higher cost, lower profit);

- ignition of drying assemblies and destruction of grain intended for drying (direct loss) forced to develop a new structure and reduce the above disadvantages.

An object of the present invention is to improve drying economy and maintain the quality of dried materials. A versatile, autonomous infrared drying assembly for agriculture producers and construction industry, which is able to efficiently dry a variety of cereals and other small-grain raw materials at minimum energy consumption in a single pass will have significant competitive advantage over all existing types of dryers worldwide.

Summary

A low-temperature slot dryer comprising in the upper section an infeed block and in the lower section a heating block with outfeed sluices, characterized in that between said infeed and outfeed elements located are alternately from the top a ventilation block and a passive heating block thereunder comprising low-temperature electric heaters with infrared radia tion, mounted vertically in rows, forming series of slots. The blocks are grouped below in subsequent similar modules, whereas the vertical elements thereof directing the falling raw material are rotated in the dryer axis in relation to each other by a right angle, forming a truss structure. The low-temperature infrared radiation heaters are apart from each other by almost 5 cm.

Low temperature used for drying in said dryer (up to 60 degrees Celsius, thus the name low-temperature) does not heat up the apparatus, which means no heat loss via the walls and ventilation. In many prior art dryers for drying cereals the grain becomes overheated and elimination of the original microflora (fungi and mould) fails. The overheated grain may not be used as seed. There are no versatile dryers on the market for a variety of loose materials to be used to dry cereals without damage, or sand to be used in construction industry for adhesives, masonry mortars or plaster products. In the instant dryer the working surface has been significantly increased in relation to the volume of the dried material. For example, heating work surface per 1 m3 of dried material = 32 square metres with which the material is in contact. For example, 1 tonne of wheat per 45 square metres of working/heating surface. It results in fast drying by resistive infrared panels.

The infrared drying method has a primary advantage over convective dryers. The new drying method is based on that the moisture in grain absorbs infrared light and is heated up, which means that the energy is directed straight onto liquids, onto moisture, which provides high efficiency and profitability. Due to application of the method, there is no need to highly increase temperature of products being dried and the “evaporation” process can be carried out in 40-60 degrees Celsius.

Low temperature does not heat up the apparatus which means no heat loss via walls and ventilation. At the same time, infrared radiation at 40-60 degrees Celsius eliminates entire microflora on the surface and inside the grain, thus leaving the grain clean as infrared radiation fully reduces pathogens in biological materials outside and inside the dried material.

The very infrared radiation is harmless to the environment and people, as well as to the dryer.

In relation to the above, it can be stated that:

- drying by infrared, in comparison to conventional convective drying, has significantly lower unit energy consumption per unit of evaporated moisture volume. High efficiency of raw material drying is achieved due to that the energy is provided not to the shell of the grain (as it is in all types of convective dryers used worldwide) but to the water inside the grain, which forces the water to find the way out of the grain (due to that the energy costs are reduced);

- the capillary system and outside and inside structure of the dried material are not disturbed;

- in industrial drying by said low-temperature slot dryer using infrared waves essential is that microtoxins, mould, fungi are removed from cereal grains, and there are no other drying devices available that ensure such efficient and similar results; - the structure allows for removal of mycotoxins and fungi in a non-invasive manner. The internal and external structure of the dried material is not disturbed. It is proved by documented corn drying research results before and after drying by certified research centres. The mycotoxin-aflatoxin and ochratoxin analysis has been performed by HPLC method with fluorescent detection. The sample has been purified by immunoaffility columns AflaTest by Vicam for aflatoxins and OchraPrep by R-BiopharmRhoneLtd for ochratoxin A, according to the procedure provided by the producer. The fumonisin analysis has been performed by HPLC-MS/MS method. The samples have been purified by MultiSep@ 211 Fum columns by Romer Labs@, according to the procedure provided by the producer. The analysis of deoxynivalenol, nival enol. diacetoxyscirpenol, zearalenon, toxin T2 and HTz has been performed by HPLC-MS/MS method. The sample has been purified by Bond Elut@ Mycotoxin columns by Agilent.

An example for decreased number of mould and yeast in the research performed by the above methods:

The number of mould in the tested sample before drying in CFU/g is 1.2 x 10 power 6. Following the drying process by said dryer the achieved results of the number of mould in CFU/gram is 2.8 x 10 power 4.

In the same analysed sample the number of yeast has also decreased.

Before the drying process CFU/gram 4.7 x 10 power 6.

After the drying process CFU/gram 8.3 x 10 power 2. There are no available similar examples worldwide for mould and yeast removal in the industrial com drying process;

- the grain is dried in low temperature 40-60 degree Celsius and energy consumption is significantly lower than when using conventional, convective methods for drying grain. It is preferably 55 degrees, which prevents the raw material from cracking, protein denaturation and fading of grain germs. It allows farmers to obtain their own seed from their own raw material (which may be more effective and economical in comparison with seed acquired from agricultural producers);

- versatility of proposed drying - successful drying provided for cereals and pulses, oilseeds, and small seeds;

- the equipment is simple, reliable, of high performance, ensures autonomy of the drying assembly with the possibility to avoid connection to the existing electric or gas supply systems (it is possible to use power generators), consists of a module structure to compile blocks;

- the quality of the dried grain is significantly higher than in the case of the conventional drying method due to infrared radiation that eliminates/kills pathogens in biological materials;

- the advantage of said solution is a total elimination of the risk of ignition of the material being dried. The dryer is completely safe.

Particular feature of infrared radiation use in food industry is the ability of infrared waves to penetrate porous capillary products, such as grains, groats, etc. to up to 7 mm in depth. The infrared wave has not only thermal but also biological impact on the product. It helps to accelerate biochemical transformations in such biological polymers as starch, protein and lipids, which cannot be achieved in convection dryers. Drying products in said technology allows to maintain vitamin and other biologically active substances content in the dry product at the level of 80-90% of the original. Due to a short immersion in water (15-20 minutes), in the product that underwent IR drying all natural physical, chemical properties are restored and the product can be used both fresh or after any culinary processing.

Infrared drying provides products that do not contain harmful substances that are present in drying facilities where the heating agent is heating oil or gaz. The very infrared radiation is harmless to the environment and people due to the sun that is the main source of infrared radiation and which has been used for centuries to dry food.

An embodiment of the invention is presented in the drawing where Fig. la shows a view of the dryer, Fig. la a scattered view of the primary dryer blocks, Fig. 2 a view of the ventilation block, Fig. 3 a view of the passive heating block, and Fig. 4 a view of the lowest located heating and outfeed block, located on an exemplary frame base.

The slot dryer in the upper section is provided with an infeed block 1, with “air sluice”. The raw material for drying is added therethrough and also the material undergoing drying is directed thereby to the desired direction. A ventilation block 2 is located thereunder. Located inside the block, arranged parallely at each other transfer elements provide even supply of air onto the entire surface of the dryer block and even distribution of the raw material undergoing drying. Air flow is forced by suction ventilators located outside the dryer body connected via electric cables with the dryer automation. To the suction ventilators connected are pipes transporting suction air providing transportation of the material undergoing drying. Turning the ventilators on or off is provided from the automation of the dryer based on the programmed values for humidity and temperature read out from the temperature and humidity sensors located in the dryer blocks. Underneath the block 2 located is a passive heating block 3 which is a temporary container. The number of ventilation blocks and passive heating blocks is modified depending on the raw material. Also, the number and composition sequence thereof is modifiable, however preferably the ventilation block 2 and passive heating block 3 are located alternately. Also, preferably the upper block in the alternate module structure is the ventilation block 2. It is also significant that subsequent passive heating blocks are rotated in the dryer axis in relation to each other by a right angle. Such that in the view from the top (towards the inside of the module structure) they form a truss structure. Preferably, at the bottom of the alternate blocks 2 and 3 located is the ventilation block 2, which is placed on a heating block 4. Said block is structured similarly to the passive heating blocks 3 and consists low-temperature electric heaters with infrared radiation 5 (which temperature in the heating blocks does not exceed 60 degree Celsius), mounted vertically in each of the heating block forming slots of 5 cm width in relation to each other, which prevents from adhesion and suspension of the mass of any loose raw material. Each of the heaters is connected via electric cables to the dryer automation that turns on or off the heaters based on the temperature of the sensors located inside the block. The block 4 consists, in contrary to blocks 3, additional elements for outfeeding. Four outfeed sluices 6 provide even movement of the raw material on the entire surface and vertically in the dryer body, which results in the entire load of the dried material being dried at the same time. The sluices are driver by electric motors connected by an electric cable to the automation of the dryer.

The following processes take place in the dryer: blowing with heating (drying from the top) of the surface layer. It is performed in the upper block 2 to facilitate infrared radiation passage to the core of the raw material. In the lower located block 3 heating by infrared takes place (heating from the inside) - heating and temperature uniformity, achieving thermodynamic balance in relation to the dry air. Then, the above processes (steps) are repeated, however in the upper section of the dryer the processes of raw material surface moisture removal dominates while the removal of the moisture from the inside of the raw material grains prevails in the lower. The drying process is continuous, however the time when the raw material is in the dryer is from an hour to about four hours depending on the type of the raw material. It depends on moisture and temperature of the raw material infed for drying and outside air temperature and humidity around the dryer.

In said resistive heaters the electric power is 230 V and 50 Hzcos(cp) is ~1, which is environment and people friendly. In the environment around people any electric devices are powered also by electricity of 230 V and 50 - 60 Hz.