scholarly journals Conveyor-Belt Dryers with Tangential Flow for Food Drying: Development of Drying ODEs Useful to Design and Process Adjustment

Inventions ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Dario Friso

The mathematical investigation presented in this paper concerns the conveyor-belt dryer with tangential flow operating in co-current. This dryer is bigger than the continuous through-circulation conveyor dryer but has the advantage of better preserving the organoleptic and nutritional qualities of the dried product. In a previous work a mathematical modeling of the conveyor-belt dryer with tangential flow was carried out to offer guidelines for its optimized design. The last of those design guidelines indicated the need for an optimized adjustment of the dryer to ensure the constant maintenance of the final moisture content of the product. The fast and very precise measurement of the moisture content as the first step in the feedback chain was therefore necessary. Considering the difficulty of this type of measurement, two specific ordinary differential equations (ODEs) were obtained with the mathematical investigation of this work. Their solution became a relationship between the final moisture content of the product, the outlet air temperature, and other quantities that could be easily implemented in an automatic dryer control system. Therefore, the fast and accurate and much less expensive measurement of the temperature of the air leaving the dryer, owing to the relationship found, replaces the measurement of moisture content for the adjustment system. The experimental verification of the relationship highlighted the need to introduce a modification by which the relationship was finally validated.

Inventions ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Dario Friso

The mathematical modeling presented in this work concerns the conveyor-belt dryer with the tangential flow of air with respect to food. This dryer, if operating in co-current, has the advantage of well preserving the organoleptic and nutritional qualities of the dried product. In fact, it has a low air temperature in the final stretch where the product has low moisture content and is therefore more temperature sensitive. It is a bulkier dryer than the continuous through-circulation conveyor dryer with a perforated belt. The latter is therefore more frequently used and has received greater study attention from researchers and designers of the industry. With the aim to propose guidelines for a rational design of the conveyor-belt dryer with tangential flow, a mathematical model was developed here through the differentiation of the drying rate equation followed by its integration performed along the dryer belt. Consequently, and with the assumption that the final moisture content XF of the product is higher than the critical moisture content XC, the relationships between the intensive quantities (temperatures, humidity and enthalpies), the extensive quantities (air and product flow rates) and the dimensional ones (length and width of the belt), were obtained. Finally, on the basis of these relationships, the rules for an optimized design for XF > XC were obtained and experimentally evaluated.


Inventions ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 43
Author(s):  
Dario Friso

This work presents the mathematical modeling of the conveyor-belt dryer with tangential flow operating in co-current, which has the advantage of improving the preservation of the organoleptic and nutritional qualities of the dried food. On the one hand, it is a more cumbersome dryer than the perforated cross flow belt dryer but, on the other hand, it has a low air temperature in the final section where the product has a low moisture content and, therefore, it is more heat sensitive. The results of the mathematical modeling allowed a series of guidelines to be developed for a rational design of the conveyor-belt dryer with tangential flow for the specific case of the moisture content of the final product XF lower than the critical one XC (XF < XC). In fact, this work follows a precedent in which a mathematical model was developed through the differentiation of the drying rate equation along the dryer belt with the hypothesis that the final moisture content XF of the product was higher than the critical one XC. The relationships between the extensive quantities (air flow rate and product flow rate), the intensive quantities (temperatures, moisture content and enthalpies) and the dimensional ones (length and width of the belt) were then obtained. Finally, based on these relationships, the rules for an optimized design for XF < XC were obtained.


1976 ◽  
Vol 39 (4) ◽  
pp. 244-245 ◽  
Author(s):  
G. BEETNER ◽  
T. TSAO ◽  
A. FREY ◽  
K. LORENZ

Triticale kernels were extruded using a Brabender Plasticorder extruder with ¾-inch rifled barrel and 1:1 flight depth ratio screw. Whole grain samples were extruded at initial moisture contents of 15, 20, and 25%. Debranned samples were extruded at an initial moisture content of 22%. Barrel temperatures of 350, 400, and 450 F and nozzle openings of 1/8 inch and 1/16 inch were used. The products were analyzed for thiamine and riboflavin content. Results were corrected for final moisture content and expressed as fraction retained. A multiple regression was done to determine the relationship between independent and derived variables, and the retention. Riboflavin retention was correlated simply as a function of barrel temperature. Thiamine retention of the debranned material was correlated as a function of nozzle size and barrel temperature. Thiamine retention of the whole grain samples was correlated for nozzle size, first and second order temperature effects, and confounding between nozzle size and temperature.


2018 ◽  
Vol 38 (2) ◽  
pp. 217
Author(s):  
Abadi Jading ◽  
Nursigit Bintoro ◽  
Lilik Sutiarso ◽  
Joko Nugroho Wahyu Karyadi

Flour drying could be conducted by using pneumatic conveying dryer (PCD) or flash dryer, but generally it is required a high vertical pipe. The high of vertical pipe may be replaced with a recirculation process to produce a required final moisture content of the material. This study had designed pneumatic conveying recirculated dryer (PCRD) to dryi of wet sago starch. Later, the design was used to determine a mathematical model of the relationship between the variables of drying process with final moisture content of the material. The purpose of this study was to develop a mathematical model of the relationship between the final moisture content of wet sago starch  with variables drying process and recirculation continuously in the pneumatic conveying recirculated dryer (PCRD) using dimensional analysis. Buckingham Phi Theorem methods of dimensional analysis was used to find the relationship variables that affect the final moisture content of wet sago starch on the PCRD machine. The mathematical model generated in this study is      The coefficient of determination (R2) of the mathematical model was 0.948, or 94.8 %, indicated that the model was valid to predict the final moisture content of wet sago starch in designing PCRD machines. While the sensitivity of the test results showed that the dimensionless product of the most influential are , , and . The model was applicable for drying wet sago starch or other starch material which is similat to the physical properties of wet sago starch. ABSTRAKPengeringan bahan-bahan tepung dapat dilakukan dengan pneumatic conveying dryer (PCD) atau flash dryer, namun umumnya memerlukan pipa vertikal yang cukup tinggi. Pipa vertikal yang tinggi dapat diganti dengan proses resirkulasi untuk menghasilkan kadar air akhir bahan yang disyaratkan. Pada penelitian ini telah dirancang pneumatic conveying recirculated dryer (PCRD) untuk mengeringkan pati sagu basah, serta dicari model hubungan matematis antara variabel-variabel proses pengeringan dengan kadar air akhir. Tujuan penelitian ini adalah mengembangkan model matematis hubungan antara kadar air akhir pati sagu basah dengan variabel-variabel proses pengeringan resirkulasi secara kontinyu pada pneumatic conveying recirculated dryer (PCRD) menggunakan analisis dimensi. Metode Buckingham Phi Theorem dalam analisis dimensi digunakan untuk mencari hubungan variabel-variabel yang berpengaruh terhadap kadar air akhir pati sagu basah pada mesin PCRD. Model matematis yang dihasilkan pada penelitian ini adalah      Nilai koefisien determinasi (R2) dari model matematis tersebut adalah 0,948 atau 94,8 %, menunjukkan bahwa model tersebut valid digunakan untuk memprediksi kadar air akhir pati sagu basah dalam merancang mesin PCRD. Sedangkan hasil uji sensitivitas menunjukkan bahwa dimensionless product yang paling berpengaruh adalah , , dan . Model tersebut berlaku untuk pengeringan pati sagu basah atau bahan-bahan tepung lainnya yang sifat fisiknya identik dengan pati sagu basah.


2006 ◽  
Vol 2 (1) ◽  
pp. 51-72
Author(s):  
István Patay ◽  
Virág Sándor

Clod crushing is a principal problem with soils of high clay content. Therefore, there is a need for determining the conditions for clod breaking and clod crushing. The objective of the work was to develop a special purpose tool for single clod breaking both by rigid support of the clod and by a single clod supported by soil and to develop a machine for clod crushing. Furthermore, the purpose was to determine the relationship between the specific energy requirement for clod crushing in the function of soil plasticity and the soil moisture content by the means of the developed tool and machine. The main result of the experiments is summarized in a 3D diagram where the specific energy requirement for soil clod crushing is given in the function of the moisture content and the plasticity index for different clay soils.


Author(s):  
O. A. Zadorozhna ◽  
T. P. Shyianova ◽  
M.Yu. Skorokhodov

Seed longevity of 76 spring barley gene pool samples (Hordeum vulgare L. subsp. distichon, convar. distichon: 56 nutans Schubl., two deficience (Steud.) Koern., two erectum Rode ex Shuebl., two medicum Koern.; convar. nudum (L.) A.Trof.: one nudum L. та subsp. vulgare: convar. vulgare: nine pallidum Ser., three rikotense Regel.; convar. coeleste (L.) A.Trof.: one coeleste (L.) A.Trof.) from 26 countries, 11 years and four places of reproduction was analyzed. Seeds with 5–8% moisture content were stored in chamber with unregulated and 4oC temperature. The possibility of seed storage under these conditions for at least 10 years without significant changes in germination has been established. The importance of meteorological conditions in the formation and ripening of seeds for their longevity is confirmed. The relationship between the decrease of barley seeds longevity and storage conditions, amount of rainfall, temperature regime during the growing season of plants is discussed.


Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.


2014 ◽  
Vol 635-637 ◽  
pp. 750-754
Author(s):  
Peng Hu ◽  
Qing Li ◽  
Yi Wei Xu ◽  
Nan Ying Shentu ◽  
Quan Yuan Peng

Expound the importance of soil shear strength measurement at mudslide hidden point to release the loss caused by the disaster, explain the relationship between shear wave velocity, moisture content and shear strength, design the shear strength monitoring system combining the shear wave velocity measured by Piezoelectric bender elements and moisture content.


1997 ◽  
Vol 74 (5) ◽  
pp. 566-570 ◽  
Author(s):  
Elaine T. Champagne ◽  
Karen L. Bett ◽  
Bryan T. Vinyard ◽  
Bill D. Webb ◽  
Anna M. McClung ◽  
...  

Author(s):  
Sean O'Sullivan ◽  
John Morrall

A quantifiable basis for developing design guidelines for pedestrian access to light-rail transit (LRT) stations is provided for planners based on observations in Calgary, Canada. Calgary's LRT system, which began operations in 1981, has been operating for long enough for walking patterns to and from its stations to become established. Interviews were conducted with 1,800 peak-hour LRT users about the origins and destinations of their LRT trips. Those who walked to or from a station were asked to point out on a map their approximate origins or destinations. The distances were then measured off the maps. Walking distance guidelines were developed for central business district (CBD), transfer and local stations. Catchment area maps were produced, and the relationship between reported walking time and measured walking distance was calculated. Also compared are the walking distances at LRT stations and the walking distances at bus stops. The research strongly indicates that people walk farther to reach an LRT station than a bus stop. Using bus walking standards would result in an underestimate of LRT walking distances by about half. For the city of Calgary the average walking distance to suburban stations is 649 m with a 75th-percentile distance of 840 m. At CBD stations the average walking distance is 326 m and the 75th-percentile distance is 419 m.


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