General principles of temperature measurement: study of J and K type thermocouples calibration
DOI:
https://doi.org/10.36560/1022017253Palavras-chave:
medição de temperatura, termopar, curva de calibração, constante de tempo, erro de histerese.Resumo
This study aims to determine and analyze the calibration and hysteresis curves of K and J type thermocouples. From these studies were obtained the dynamic characteristics of the analyzed thermocouples. To determine the calibration and hysteresis curves the thermocouples were submitted to different temperatures in order to obtain the respective tension values. From the obtained voltage versus temperature curve it was possible to see that the generated voltage is linearly proportional to the difference of temperature between the hot and reference junctions. Then, the curve’s slope was obtained in order to determine the thermocouple’s Seebeck coefficient. The obtained values were50.4±1.1 µV/°C and 39.2±1.0 µV/°C for K and J type, respectively. Maximum hysteresis error of 3.71 % for J type and 3.04% for K type were obtained. Analyzing the hysteresis curves it was possible to conclude that this was a random error, since it is always present despite the experimenter’s level of caution. Submitting the K type thermocouple to a step temperature excitation it was possible to obtain a temperature versus time curve. From this curve the thermocouple’s time constant was determined to be 27.6 s. Mathematically, from an energy balance, it was determined that the J type thermocouple has a time constant of 21.8 s and the K type 27.1 s, that is, the J type thermocouple responds faster to temperature change.Referências
Doebelin, Ernest, 2003, “Measurements Systems: Application and Designâ€, Ed.Mcgraw-Hill, 5ª Edição.
Hiraka, K. et al, 2008, “Rapid Response Hybrid Type Surface Temperature Sensorâ€.
Holman, J.P., 2003, “Experimental Methods for Engineersâ€, Ed. McgrawHill.
Incropera, Frank P. et al, 2008, “Fundamentos de transferência de calor e massaâ€, 6ª edição, Ed. LTC.
Jorge, Luiz Mariode Matos et al, 2003, “Determinação e análise das constantes de tempo de um sensor anelar de temperatura em leito fixoâ€, Acta Scientiarum Technology.
MartÃnez, Patricia; Azuaga, Marcelo, 1997, “Calibrácion de una termocupla de Chromel – Alumelâ€, Departamento de FÃsica, Universidade de Buenos Aires.
Moreira, Lúcia, 2002, “Medição de temperatura usando-se termoparâ€, Cerâmica Industrial.
Neto, Antonio J. Steidle; Zolnier, Sérgio, 2006, “Avaliação de circuito eletrônico para medição de temperatura em instalações agrÃcolas por meio da porta paralela de um computadorâ€, Eng. AgrÃcola, Jaboticabal.
Ogata, K. , 2003, “Engenharia de Controle Modernoâ€, 4ª Edição, Ed. Pearson.
Pires, Denise Prazeres Lopes et al, 2006, “A Termometria nos séculos XIX e XXâ€, Revista Brasileira de Ensino de FÃsica, v.28.
Ribeiro, Antonio de Assis Bento et al, 2002,“Construção de um sistema eletrônico de medição usando termoparâ€.
Wheeler, A. J. e Ganji, A. R., 2009, “Introduction to Engineering Experimentationâ€, 3ª edição, Ed. Pearson.
Downloads
Publicado
Como Citar
Edição
Seção
Licença
A revista se reserva o direito de fazer alterações nas regras originais, na ortografia e na ordem gramatical, a fim de manter o idioma de culto padrão, respeitando, no entanto, o estilo dos autores. Os artigos publicados são de propriedade da revista Scientific Electronic Archives, tornando-se sua reimpressão total ou parcial, sujeitos à autorização expressa da direção da revista. A fonte original da publicação deve ser mantida. Os originais não serão devolvidos aos autores. As opiniões expressas pelos autores dos artigos são de sua exclusiva responsabilidade.
The journal reserves the right to make changes to the original rules, spelling and grammatical order, in order to keep the language of worship default, respecting, however, the style of the authors. Articles published are the property of Scientific Electronic Archives magazine, becoming its total or partial reprint, subject to the express authorization of the direction of the journal. The original source of publication should be retained. The originals will not be returned to the authors. Opinions expressed by authors of articles are solely your responsibility.
This journal uses the License Creative Commons Atribuição 4.0 Internacional.
