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When studying the kinetics of high-temperature wheat drying, it is found that at the end of the constant drying period, there is a sharp increase in the grain heating temperature. The temperature jump occurs due to the grain surface dehydration, when the average relative moisture is close to standard and makes 15...16 %. Based on this regularity, the method of exposure control of grain drying in high-temperature dryers without using continuous-flow moisture meters is developed. The method is based on simultaneous control of the material heating temperature by temperature sensors over the entire length of the drying chamber. The measured values from the temperature sensors are transmitted to the microcontroller in order to periodically approximate them with the cubic polynomial and find the derivative of the second-order function. The microcontroller is programmed to determine the second-order critical point – the location of the grain, having standard moisture. The obtained result is compared with the maximum length of the grain path along the drying chamber in order to subsequently influence the discharger performance. The developed method of exposure control of grain drying in high-temperature dryers provides the necessary time for the temperature effect of the drying agent on the grain, process quality and reduction of energy consumption for grain drying. On the basis of this method, the drying process without the use of expensive continuous-flow grain moisture meters operating with a high measurement error is automated.

При сушке зерна существует проблема точности определения влажности материала, особенно в потоке по причинам сложности конструкции влагомеров, высокой погрешности измерений, кроме этого, они обладают высокой стоимостью и сложно монтируются в сушилки. Из-за погрешности измерений датчиками затруднено определение окончания сушки зерна, на выходе из сушилок наблюдается разброс влажности зерен. При этом возможен режим пересушивания зерна, при котором перерасход энергии достигает 58,3 МДж на 1% излишне испаренной влаги с высушенной тонны. При недосушке оператор технологической линии осуществляет повторный пропуск зерна через сушилку, что приводит к снижению ее производительности и травмированию влажного зерна от дополнительного взаимодействия с рабочими органами машин. С целью уменьшения затрат энергии на сушку и повышения качества семенного материала разработан способ контроля окончания сушки без использования влагомеров. Способ основан на постоянном контроле температуры семян и поиске участка, на котором происходит температурный скачек по причине обезвоживания семян. В соответствии с кинетикой сушки капиллярно-пористых коллоидных тел в момент начала интенсивного роста температуры влажность семян близка к кондиционной. Разработано устройство определения окончания сушки зерна по характеру изменения температуры в процессе их обезвоживания. Устройство состоит из пирометрических датчиков, соединённых с измерительной схемой индикаторного блока, микропроцессора и блока получения и обработки данных, обратных линий связи. Управляющие линии связаны с приводом выпускного устройства при использовании устройства в сушилках непрерывного действия, при использовании в сушилках периодического действия с системой управления работой теплогенератора. Разработанное устройство прошло проверку в производственных условиях. При сушке высоковлажных семян сои в сушилке плотного слоя с его помощью точно определяется время окончания теплового воздействия на семена при достижении ими влажности 11,4–12,0%, соответствующей кондиционной., When drying grain, there is a problem of accuracy for the material moisture content determining, especially in the flow due to the complexity of moisture meters design, high measurement error, in addition, they have a high cost and are difficult to install in dryers. Due to the measurement error by the sensors, it is difficult to determine the end of grain drying; at the exit from the dryers, a dispersion of grain moisture is observed. In this case, the regime of grain over-drying is possible, in which the energy expenditure reaches 58.3 MJ per 1% of excessively evaporated moisture from the dried ton. In case of a lack of drying, the operator of the processing line re-passes the grain through the dryer, which leads to a decrease in its productivity and injury to wet grain from additional interaction with the working bodies of the machines. In order to reduce energy costs for drying and improve the quality of seed material, a method for controlling the end of drying without the use of moisture meters has been developed. The method is based on the constant monitoring of the temperature of the seeds and the search for the area where the temperature jump occurs due to dehydration of the seeds. In accordance with the kinetics of drying of capillary-porous colloidal bodies, at the moment of the beginning of an intensive temperature increase, the seed moisture is close to conditional. A device has been developed to determine the end of grain drying by the nature of temperature changes during their dehydration. The device consists of pyrometric sensors connected to a measuring circuit of an indicator unit, a microprocessor and a unit for receiving and processing data, and reverse communication lines. The control lines are connected to the drive of the exhaust device when using the device in continuous dryers, when used in periodic dryers with a control system for the operation of the heat generator. The developed device has been tested in a production environment. When drying high-moisture soybean seeds in a dense-layer dryer, it accurately determines the time of termination of the thermal effect on the seeds when they reach a moisture content of 11.4–12.0%, corresponding to the conditional one.

Com o objetivo de avaliar a viabilidade de uso da técnica ultrassônica para estimar o teor de umidade da madeira durante o processo de secagem, amostras de Pinus elliottii Engelm. e Eucalyptus grandis W. Hill ex Maiden, com dimensões nominais 3,5 x 10 x 25 cm de espessura, largura e comprimento, respectivamente, foram submetidas às temperaturas de 20, 40 e 70ºC. Um equipamento ultrassônico PUNDIT com transdutores de faces planas de 50 kHz foi utilizado para medir a velocidade de propagação do som na direção longitudinal da madeira. Os resultados indicaram aumento da velocidade ultrassônica estimada em função da redução do teor de umidade. Essa relação mostrou-se válida no intervalo desde verde até o final da secagem, sendo que os melhores coeficientes de determinação ocorreram na madeira de eucalipto (R² = 81%). Embora não tenha sido observada uma influência da espécie na velocidade ultrassônica, esta foi influenciada pela massa específica da madeira e pela temperatura de secagem. O efeito da massa específica foi diretamente proporcional para a madeira de pinus e inversamente proporcional para a madeira de eucalipto. A velocidade ultrassônica apresentou tendência de redução com o aumento da temperatura de secagem para ambas as espécies, e os resultados obtidos sugerem que o método ultrassônico apresenta bom potencial para o controle do processo de secagem. With the purpose of evaluating the viability of use of ultrasonic technique to estimate the wood moisture content during the drying process, samples of Pinus elliottii Engelm. and Eucalyptus grandis W. Hill ex Maiden with dimensions of 3.5 cm thick, 10 cm width and 25 cm long were submitted to drying temperatures of 20, 40 and 70ºC. A PUNDIT ultrasonic equipment with plane face transducers by 50 KHz was used to measure sound velocity in the longitudinal direction of the wood. Results indicated increase of estimated ultrasonic speed with reduction of moisture content. This relationship showed to be valid for the wood from green to the end of the drying process, and the best determination coefficients were found in the eucalypt wood (R² = 81%). Although no influence of the species in the ultrasonic speed has been observed, this one was influenced by the wood specific gravity and by the drying temperature. The effect of the specific mass was directly proportional for the pinus wood. Opposite effect was observed in eucalypt wood. The ultrasonic speed tended to decrease as drying temperature increased for both species. Results suggest that this method presents good potential for the control of the drying process.

The authors acknowledge the Drying Technology journal for their copyright policies & self-archiving. More open archives publications of Pascal Dufour are available on: http://hal.archives-ouvertes.fr/DUFOUR-PASCAL-C-3926-2008; International audience; This paper deals with the experimental control of an infrared drying process of a water based epoxy-amine painting. This approach is based on a unidirectional diffusional modelling of infrared drying phenomena where both heat and mass transfers under shrinkage conditions are accounted for. The control problem is concerned with the tracking of any given trajectory for one of the characteristics (i.e. the temperature or the mean water content) during the drying cycle. This is solved using the well-known model predictive control framework where the non-linear diffusional model is directly used in the control formulation. Experimental results show the efficiency of the trajectory tracking. This method can be extended for more general constrained control problem.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2016-08-10T13:36:29Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_rafael_galli.pdf: 1784612 bytes, checksum: 53c4719f6d1fddfd10b5cf2af2a61308 (MD5) Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-08-10T14:10:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_rafael_galli.pdf: 1784612 bytes, checksum: 53c4719f6d1fddfd10b5cf2af2a61308 (MD5) Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-08-10T14:13:06Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_rafael_galli.pdf: 1784612 bytes, checksum: 53c4719f6d1fddfd10b5cf2af2a61308 (MD5) Made available in DSpace on 2016-08-10T14:13:15Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_rafael_galli.pdf: 1784612 bytes, checksum: 53c4719f6d1fddfd10b5cf2af2a61308 (MD5) Previous issue date: 2014-09-17 Sem bolsa O presente trabalho foi realizado como objetivo desenvolver e avaliar um sistema eletrônico, que permita a supervisão e armazenamento de dados em um silo de secagem, visando um sistema confiável e de baixo custo, que permita sua implantação em propriedades de pequeno porte ou mesmo de grande porte. Um sistema de fácil implementação e de simples operação. O sistema é composto de placas de aquisição microprocessadas, que durante a secagem do produto realizam aquisição de temperatura em três níveis, topo, centro e base dos silos, como também da umidade relativa do ar de entrada e saída, transmitindo estas informações para uma central (computador), via Bluetooth onde as mesmas são armazenadas para posterior análise. This study aimed to develop and evaluate an electronic system, that allows monitoring and data storage in a silo drying, seeking a reliable and low cost system that allows its deployment in small or even large industrial plants. A system of easy implementation and simple operation. The system consists of microprocessor acquisition boards that during drying of the product perform temperature acquisition in three levels, top, middle and base of the silos, as well as the relative humidity input and output, transmitting this information for a central (computer) via Bluetooth where they are stored for later analysis.

The aim of this study was to determine whether NIRS technology would be suitable to develop a control system to correct drying conditions in order to avoid the appearance of defects in the product. Several predictive models for moisture, aw, and the salt content on the surface of the products (dry-cured sausages and dry-cured hams) have been obtained for the entire process, and an on-line control of the drying process have been developed., L’objectiu d’aquest treball ha estat determinar si la tecnologia NIRS és una tècnica adequada per poder desenvolupar un sistema de control de l’assecat que corregeixi les condicions de treball dels assecadors evitant l’aparició de defectes en el producte. S'han obtingut models de predicció de la humitat, la aw i el contingut de sal a la superfície dels productes (llonganissa i pernil curat) en tot el procés d’elaboració i s'ha desenvolupat un sistema de control on-line del procés d’assecat.

RESUMO Com o objetivo de avaliar a viabilidade de uso da técnica ultrassônica para estimar o teor de umidade da madeira durante o processo de secagem, amostras de Pinus elliottii Engelm. e Eucalyptus grandis W. Hill ex Maiden, com dimensões nominais 3,5 x 10 x 25 cm de espessura, largura e comprimento, respectivamente, foram submetidas às temperaturas de 20, 40 e 70ºC. Um equipamento ultrassônico PUNDIT com transdutores de faces planas de 50 kHz foi utilizado para medir a velocidade de propagação do som na direção longitudinal da madeira. Os resultados indicaram aumento da velocidade ultrassônica estimada em função da redução do teor de umidade. Essa relação mostrou-se válida no intervalo desde verde até o final da secagem, sendo que os melhores coeficientes de determinação ocorreram na madeira de eucalipto (R² = 81%). Embora não tenha sido observada uma influência da espécie na velocidade ultrassônica, esta foi influenciada pela massa específica da madeira e pela temperatura de secagem. O efeito da massa específica foi diretamente proporcional para a madeira de pinus e inversamente proporcional para a madeira de eucalipto. A velocidade ultrassônica apresentou tendência de redução com o aumento da temperatura de secagem para ambas as espécies, e os resultados obtidos sugerem que o método ultrassônico apresenta bom potencial para o controle do processo de secagem. ABSTRACT With the purpose of evaluating the viability of use of ultrasonic technique to estimate the wood moisture content during the drying process, samples of Pinus elliottii Engelm. and Eucalyptus grandis W. Hill ex Maiden with dimensions of 3.5 cm thick, 10 cm width and 25 cm long were submitted to drying temperatures of 20, 40 and 70ºC. A PUNDIT ultrasonic equipment with plane face transducers by 50 KHz was used to measure sound velocity in the longitudinal direction of the wood. Results indicated increase of estimated ultrasonic speed with reduction of moisture content. This relationship showed to be valid for the wood from green to the end of the drying process, and the best determination coefficients were found in the eucalypt wood (R² = 81%). Although no influence of the species in the ultrasonic speed has been observed, this one was influenced by the wood specific gravity and by the drying temperature. The effect of the specific mass was directly proportional for the pinus wood. Opposite effect was observed in eucalypt wood. The ultrasonic speed tended to decrease as drying temperature increased for both species. Results suggest that this method presents good potential for the control of the drying process.

The aim of this paper is to contribute to the discussion of the methodology that leads to a better systematization of the knowledge on solar drying. Based on a case study for the lumber industry, the options and solutions adopted will be reported, along with their evaluation criteria and existing or developed tools. The kilns have 50 m3 interior capacity and proved the capability to dry maritime pine 27 mm thick, from green to 12% moisture content in about 33 days. The performance of the drying process has a significant seasonal and weather dependence, so an interactive control system is essential in order to profit as much as possible from the favorable exterior conditions.

Conselho Nacional de Desenvolvimento Científico e Tecnológico The purpose of this study is to explore the use of ultrasonic technique in order to estimate the moisture content during wood drying, from green condition to the end of the drying process. The treatments were based on the combination of two different species (Pinus elliottii Engelm. and Eucalyptus grandis Hill ex Maiden), drying temperatures (20, 40 and 70ºC) and transducers types (plane faces and dry points). The experiment was set up according to a factorial model, with approximately 50 replications. A 50 kHz - transducer (PUNDIT ultrasonic equipment) was used. Samples tested had nominal 3.5 cm thick by 10 cm wide by 25 cm long and the ultrasonic wave speed propagation was measured according to its longitudinal direction. The results indicated increase of ultrasonic speed with reduction of moisture content for both transducers used. This relationship is valid for the wood from green to the end of the drying process. However, low correlation was observed, and the best model adjusted determination coefficients were observed with eucalypt wood (Raj.²= 88%). The use of the transducers of dry points was more practical than the plane faces one. Moreover, they should be used in hard and not much heterogeneous woods. The ultrasonic velocity was also influenced by wood density and drying temperature. The species showed different effects of wood density on the velocity. In the pine wood, velocity increased with increasing density. Opposing effect was observed in eucalypt wood. The ultrasonic speed tended to decrease as drying temperature increased. Nevertheless, this variable s influence was reduced. It was not noticed any defined influence of the species in the ultrasonic speed when the plane face transducers were used. However, the eucalyptus wood provided larger velocity when the dry point transducers were used. The results suggest that this method presents good potential for the control of the drying process. Studies on the influence of the several wood characteristics on the ultrasonic wave s velocity and the development of specific transducers for the use of this alternative in commercial scale are required. O objetivo deste estudo foi explorar o uso da técnica ultra-sônica para estimar o teor de umidade da madeira durante sua secagem, desde a condição verde até o final do processo. Os tratamentos basearam-se na combinação de duas espécies (Pinus elliottii Engelm. e Eucalyptus grandis Hill ex Maiden), temperaturas de secagem (20, 40 e 70ºC) e tipos de transdutores (faces planas e pontos secos). O experimento foi estabelecido segundo modelo fatorial, com aproximadamente 50 repetições por tratamento. Utilizou-se um equipamento ultra-sônico PUNDIT, com transdutores de 50 kHz. As amostras testadas apresentaram dimensões nominais de 3,5 x 10 x 25 cm de espessura, largura e comprimento, respectivamente e a velocidade ultra-sônica foi determinada considerando-se o plano longitudinal. Os resultados indicaram aumento da velocidade ultra-sônica estimada em função da redução do teor de umidade, para ambos os transdutores. Esta relação apresentou-se válida para a madeira desde verde até o final da secagem. No entanto, foi observada baixa correlação, sendo que os melhores coeficientes de determinação ajustados ocorreram à madeira de eucalipto (Raj.²= 88%). O uso dos transdutores de pontos secos apresentou-se mais prático do que o uso do de faces planas, devendo ser utilizados em madeiras duras e pouco heterogêneas. A velocidade ultra-sônica também foi influenciada pela densidade da madeira e pela temperatura de secagem. As espécies proporcionaram efeitos distintos da densidade sobre a velocidade. Na madeira de pinus, a velocidade aumentou com o aumento da densidade, ao passo que na de eucalipto ocorreu efeito inverso. A velocidade ultra-sônica apresentou tendência de redução em virtude do aumento da temperatura de secagem. No entanto, a influência desta variável foi reduzida. Não foi observada influência definida das espécies sobre a velocidade ultra-sônica quando utilizados os transdutores de faces planas. Porém, a madeira de eucalipto proporcionou maior velocidade quando utilizados os transdutores de pontos secos. Os resultados sugerem que este método apresenta bom potencial para ser usado no controle do processo de secagem. Entretanto, são necessários estudos sobre a influência das diversas características das madeiras sobre a velocidade das ondas ultra-sônicas, bem como o desenvolvimento de transdutores específicos para o uso desta alternativa em escala comercial.