The drying characteristics of chrome-tanned leather / E. P. Lhuede in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 57 (Année 1973)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 57 (Année 1973) . - p. 99-106 Titre : The drying characteristics of chrome-tanned leather Type de document : texte imprimé Auteurs : E. P. Lhuede, Auteur Année de publication : 1973 Article en page(s) : p. 99-106 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir -- Séchage Cuirs et peaux -- Teneur en eau Tannage au chrome Tannage végétal Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The drying characteristics of chrome-tanned as a porous medium have been examined with particular reference to the falling rate period of drying between approximately 95% and 12% moisture contents. Samples 020 m2 have been used with thicknesses ranging from 2.0 to 4.5 mm and with drying air velocities of 2.0 to 7.8 m/sec. Averaged drying rate and moisture content values have been computed from weight loss-time readings and the results plotted. Three findings emerged : first and perhaps predictably, drying times are dependent on the 0.6 power of the velocity of the air flow over the leather surface according to conventional heat transfer theory. This relationship is true up to about 2.5 mm leather thickness and has important practical implications. Secondly the moisture content-drying rate relationship can be represented by three straight lines with intersections at 30% and 18% moisture content and the system has three distinct falling rate periods. Thirdly drying times for the system considered are linearly related, but not directly proportional to leather thickness. The last two of these observations indicate that the equations derived for the drying ofa simple capillary system are limited in their application of the drying of chrome leather. Note de contenu : - Drying rates for chrome-tanned leathers - Effect of air velocity on drying time - Effect of thickness on drying time - Vegetable tanned leather of varying thicknesses - Practical considerations - Fig. 1 : Moisture content parameter expressed as a ratio of the moisture content at a given time in excess of the equilibrium value (12.1%-12.6%) divided by the difference between the critical value (95 %) and the equilibrium figure. The curves are for three thicknesses - Fig. 2a : A computer plot of moisture content-rate of drying indicating the 30% discontinuity - Fig. 2b : The plot of Fig. 2a expanded to cover the moisture content range 12% to 50% (approx.) indicating a possible second discontinuity at about 17% moisture content - Fig. 3 : A drying rate-moisture content plot to an equilibrium moisture content of 5.5% showing the "18%" and "30%" discontinuities - Fig. 4 : Drying times for a chrome leather of thicknesses 2.5 mm to 30% and 13% moisture contents from a critical moisture content of 95% at a range of drying air velocities - Fig. 5 : Leather thickness and drying times for the falling rate period to and 30% to 12% (aprox.) moisture contents at three velocities - Table 1 : Drying times for a range of air velocities for a corrected leather thickness of 2.45 mm - Table 2 : Gradient of moisture content-drying rate plots over three invervals with a linear relationship between the discontinuities and for a range of air velocities - Table 3 : Drying times to various moisture contents at three velocity levels and varying substance - Table 4 : Drying times for vegetable tanned soleleather of varying thicknesses En ligne : https://drive.google.com/file/d/1f9uaM2_Mtn1PRR5ZynktV0smYfyVub_h/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31690 [article]

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