DRYING DEVICES BASED ON FUNCTIONAL CERAMICS
As can be seen from the provided data, the drying rate when using ceramic coatings is significantly higher than that of the analogs.
Subsequently, using the obtained results, two types of drying units were designed, which, after further refinement, went into serial production. One is called "Feruza-Vostok," and the other is "Uzbekistan-3." The small state enterprise "Feruza" was established by the Physics and Technology Institute of the Academy of Sciences of the Uzbek SSR (now the "Physics-Sun" Research and Production Association of the Academy of Sciences of the Republic of Uzbekistan) in collaboration with the "Bolshvik" Production Association (now the Obukhovsky plant) from St. Petersburg in 1989 as part of the defense industry conversion.
Subsequently, using the obtained results, two types of drying units were designed, which, after further refinement, went into serial production. One is called "Feruza-Vostok," and the other is "Uzbekistan-3." The small state enterprise "Feruza" was established by the Physics and Technology Institute of the Academy of Sciences of the Uzbek SSR (now the "Physics-Sun" Research and Production Association of the Academy of Sciences of the Republic of Uzbekistan) in collaboration with the "Bolshvik" Production Association (now the Obukhovsky plant) from St. Petersburg in 1989 as part of the defense industry conversion.
Drying oven "Feruza-Vostok"
- 220, 50Supply voltage, V, Hz
- 0,45/0,9Power consumption, kW (Mode 1 / Mode 2)
- 340х415х725Overall dimensions, mm
- 5 кгLoading capacity of the product, up to, kg
- 15 кгWeight of the unit, kg
- 0,5-12 чDrying time (depends on the type of product), hours
The first two models, produced in Leningrad, were named "Feruza-Vostok" — a household dryer, and "Feruza Farmer," the name of which clearly indicates the intended use of this model.
The "Feruza-Vostok" dryer uses ejectors for steam removal. Without them, as mentioned earlier, steam is trapped in the working volume and begins to absorb most of the energy from the radiators, which leads to product heating due to the high temperature of the steam. This not only reduces energy efficiency but also drastically worsens the quality of the target product. It becomes darker and unevenly dried. The ejectors eliminate these problems.
By the way, about the ejectors. Almost all the designers who copied our first laboratory prototype of a compact unit, which served as the basis for all subsequent dryers, believed that the ejector was a radiation reflector to improve the efficiency of the radiant component. Practically all of them made the inner walls of the cabinet mirror-like, but they were very surprised when their "well-made" dryers worked much worse than our "wild" prototype, and their product quality was significantly inferior to ours, not to mention the noticeably higher relative energy consumption and time.
The "Feruza-Vostok" dryer uses ejectors for steam removal. Without them, as mentioned earlier, steam is trapped in the working volume and begins to absorb most of the energy from the radiators, which leads to product heating due to the high temperature of the steam. This not only reduces energy efficiency but also drastically worsens the quality of the target product. It becomes darker and unevenly dried. The ejectors eliminate these problems.
By the way, about the ejectors. Almost all the designers who copied our first laboratory prototype of a compact unit, which served as the basis for all subsequent dryers, believed that the ejector was a radiation reflector to improve the efficiency of the radiant component. Practically all of them made the inner walls of the cabinet mirror-like, but they were very surprised when their "well-made" dryers worked much worse than our "wild" prototype, and their product quality was significantly inferior to ours, not to mention the noticeably higher relative energy consumption and time.
Laboratory prototype of the dryer
In the "Uzbekistan-3" dryer, as we have already mentioned, a labyrinth steam removal system is used. This not only allowed for an increase in the load capacity by more than 1.5-2 times, but also provided an opportunity to improve energy efficiency by 15-25%, depending on the type of product. This is likely due to the fact that convection plays a significant role in the dehydration process in this system, which differs considerably from convection in a system with an ejector.
Moreover, while the height of the trays' sidewalls in the "Feruza-Vostok" is 3 cm, which generally defines the maximum "filling" level of the product, essentially acting as a dispenser, in the "Uzbekistan-3" it was possible to increase this to 6 cm without slowing down the drying speed or deteriorating the product quality. The tray length is also slightly greater. All of this allows for a more than two-fold increase in the load capacity. The maximum power in the "Uzbekistan-3" has also been increased from 0.9 to 1.0 kW.
Drying oven "Uzbekistan-3"
- 220, 50Supply voltage, V, Hz
- 0,5/1,0Power consumption, kW (Mode 1 / Mode 2)
- 340х415х725Overall dimensions, mm
- 10 кгLoading capacity of the product, up to, kg
- 14 кгWeight of the unit, kg
- 0,5-12 чDrying time (depends on the type of product), hours
The "Electrokhimprom" plant (in Chirchik) produced a dryer from the "Uzbekistan" series called "Nur," which means "Ray." It had smaller dimensions in depth, but this was compensated by the addition of another tray. It also featured a labyrinth-type system. In addition to the "Uzbekistan-3" dryer, the "Khimavtomatika" plant also mastered the production of the "Uzbekistan-4" dryer, which had 4 shelves instead of three.
Although it is stated that work needs to be done to achieve world-class product quality, in reality, the "Uzbekistan-3" dryer has already surpassed this standard in terms of product quality. Let’s consider one parameter from the German standard. According to it, products such as dried apricots or dried plums (prunes) must contain a residual moisture of 25%. Additionally, they must be treated with sulfur dioxide so intensely that it feels like eating acid when consumed. This is due to the fact that with such residual moisture, without such "acidification," the product becomes a "paradise" for the growth of microorganisms and more. Our dryers, on the other hand, dry to a residual moisture of 3-7%, while simultaneously sterilizing the product.
We have prepared recommendations for drying various products to be used as an appendix to the drying units. These are general drying principles that can be applied not only to our dryers.
- Drying of animal products and fish.
Animal products and fish are selected without significant liquid secretion and fat. If necessary, gauze or fabric linings are used. The products are cut into small pieces or slices up to 30 mm thick. Large bones are removed. It is preferable to arrange the items in a single row on each tray.
2. Drying of mushrooms.
Mushrooms should be thoroughly cleaned of dirt and debris, wiped with a dry cloth, trimmed of roots, and sliced into strips or wedges. During the drying process, it is recommended to occasionally stir the mushrooms. It is preferable to arrange them in two or three rows on each tray. It should be noted that mushrooms in our dryers dry at a fantastic speed and fully retain their appearance and ability to completely rehydrate after soaking in water.
3. Drying of berries.
The best berries to dry are blueberries, black and red currants, raspberries, blackberries, strawberries, chokecherries, and mulberries. The product is considered ready when approximately 10% of the fresh berries' weight remains after drying.
4. Drying of apples and pears.
For drying, autumn and some summer apple varieties are suitable: Antonovka, Lithuanian Pepin, Autumn Titovka, and others. Apples are sliced into rings or wedges about 5 mm thick.
To prevent the dried fruits from darkening (this also applies to potatoes), the sliced apples can be soaked for 3 minutes in a 1.5% salt solution (150 g of salt per bucket of water); a weak solution of acetic or citric acid can also be used, with the concentration needing to be adjusted beforehand, depending on the variety and its resistance to oxidation.
When ready, the apples should be elastic, dry to the touch, and no juice should be released when pressed.
It is better to dry pears that contain little fibrous tissue (Bergamot, Forest Beauty, Bessyanka, Limonka). Before drying, the fruits are washed, sorted, and cut into wedges or slices.
To prevent the dried fruits from darkening (this also applies to potatoes), the sliced apples can be soaked for 3 minutes in a 1.5% salt solution (150 g of salt per bucket of water); a weak solution of acetic or citric acid can also be used, with the concentration needing to be adjusted beforehand, depending on the variety and its resistance to oxidation.
When ready, the apples should be elastic, dry to the touch, and no juice should be released when pressed.
It is better to dry pears that contain little fibrous tissue (Bergamot, Forest Beauty, Bessyanka, Limonka). Before drying, the fruits are washed, sorted, and cut into wedges or slices.
5. Drying of tomatoes.
For drying, ripe tomatoes are selected. They are washed, sliced into rings, and then arranged on the tray, preferably in a single layer. After about half an hour, they need to be flipped to prevent sticking to the tray. This operation needs to be done only once.
6. Drying of plums, apricots.
The fruits are divided in half, the pits are removed, and then they are arranged on the tray, preferably in a single layer. They can also be dried whole. The drying time practically does not depend on this. It is important not to confuse cherry plums and their varieties with plums. This dryer does not dry them without blanching, as they have an almost waterproof skin.
7. Drying of potatoes.
Potatoes are sliced into strips or cubes. To slow down the oxidation processes during drying (and reduce darkening), it is recommended to follow the guidelines provided in subsection 4.
8. Drying of herbs.
The most convenient and labor-efficient method for harvesting and preserving dill, parsley, celery, medicinal herbs, especially in domestic conditions. It is recommended to dry each type of herb on a separate tray.
9. Drying of root vegetables.
Before drying, root vegetables should be thoroughly washed, sliced into wedges or rounds, and any small offshoots should be removed. Carrots, radishes, onions, garlic, and other products dry well.
10. Drying of peppers.
Peppers can be dried either whole or sliced into wedges or rings. As is known, dried whole peppers do not fully rehydrate using traditional drying methods. Our method allows the pepper to completely restore its appearance, color, taste, and smell after a short soaking in cold or warm water. The fruits regain their "flesh," taking on their original properties.
