IMPINGING JET DRYER

In coating and gravure printing, an impinging jet nozzle with high thermal efficiency for drying of coated film was developed.

Trial production 0f 40 kinds of nozzle enables to develop a high-performance impinging jet nozzle with heat transfer coefficient 1.5 times larger than that of current slit nozzle, through measurement of heat transfer coefficient, visualizations of air flow and heat transfer, and measuremenu of jet velocity and turbulence distribution. The purpose of the trial production was to expand a range of high heat transfer and promote turbulence compared with the current nozzle.

Paying attention to mass transfer within gravure ink coated film, drying characteristic of the film was analyzed by numerical solution of a set of equations governing the drying process in which concentration dependencies 0f the diffusion coefficient and the equilibrium vapor pressure were considered.

Applying these analyses. an industrial scale dryer with excellent drying efficiency has finally been developed.     

Analytical Electron Microscope Analysis of the Formation of BaO · 6Al2O3

The formation process of barium hexaaluminate (BaO 6Al₂O₃) from BaCO₃/γ-Al₂O₃ powders or hydrolyzed alkoxides was studied by analytical electron microscopy. Barium hexaaluminate is produced by a two-step solid-state reaction from BaCO₃ and Al₂O₃ via formation of BaO·Al₂O₃. Marked grain growth and inclusion of nonequilibrium phase were inevitable in this powder mixture process. However, in an alkoxide-derived precursor, homogeneous mixing of components is attained and hence the formation of BaO·6Al₂O₃ proceeds readily. Powders obtained by this latter route consisted of fine planar particles with a uniform size and retained a large surface area (20.2 m²/g) even after heating at 1300°C. Electron diffraction results implied that suppression of crystal growth along the c axis is the reason for the large surface area of BaO·6Al₂O₃.     

An experimental study on self-output-control characteristics of micro downwind rotor with coning soft blades

In this short paper,we have treated the aerodynamic performance of micro downwind rotor with coning soft blades experimentally.The test wind rotor has the tip diameter of 1.5 m and three two-dimensional NACA0018 blades of 0.15 m chord whose material is light,soft and pliable foam plastic for perfect safety.From the wind tunnel test,it is realized that the performance is manageable by the coning angle of the rotor blade.In the present case,an improvement of the performance in lower wind speeds is achieved by...     

Preparation and Characterization of Machinable Mica Glass-Ceramics by the Sol-Gel Process

The preparation and characterization of machinable mica glass-ceramics by the sol-gel process are described. The thermal behavior of the precursor and the optimum conditions for calcination, molding, and sintering are given. Physical, chemical, thermal, electrical, and mechanical properties are investigated, and the machinability of the ceramics is discussed.     

Preparation of hexa-aluminate catalyst thick films on α-SiC substrate for high temperature application

The coating of Mn-substituted hexa-aluminate catalysts (BaMnAl₁₁O_19-α and Sr_0.8La_0.2MnAl₁₁O_19-α) on α-SiC substrates was investigated for high temperature application above 1000 °C. The thermal stability of the hexa-aluminate catalyst films on the α-SiC substrates was significantly affected by reactivity between the oxidized layer (SiO₂) of the surfaces of the substrates and the coated layers. The Mn-substituted hexa-aluminate films were thermally less stable due to their high reactivity than unsubstituted hexa-aluminates. The Sr_0.8La_0.2MnAl₁₁O_19-α film directly coated on the substrate exfoliated from the substrate even after heating at 1200 °C due to its high reactivity to the SiO₂ layer, whereas the BaMnAl₁₁O_19-α film was stable after the same treatment. The thermal stability of the Mn-substituted hexa-aluminate film could be improved by insertion of an Al₆Si₂O₁₃ intermediate layer between the film and the SiC substrate. Additional coating of a highly crystallized Ba_0.75Al_11.0O_17.25 intermediate layer underneath the BaMnAl₁₁O_19-α catalyst layer was also effective. The Al₆Si₂O₁₃ and Ba_0.75Al_11.0O_17.25 intermediate layers suppressed the diffusion of SiO₂ from the substrate and subsequent reaction between SiO₂ and the hexa-aluminate film. This revised version was published online in November 2006 with corrections to the Cover Date.     

IMPINGING JET DRYER

ABSTRACT

In coating and gravure printing, an impinging jet nozzle with high thermal efficiency for drying of coated film was developed.

Trial production 0f 40 kinds of nozzle enables to develop a high-performance impinging jet nozzle with heat transfer coefficient 1.5 times larger than that of current slit nozzle, through measurement of heat transfer coefficient, visualizations of air flow and heat transfer, and measuremenu of jet velocity and turbulence distribution. The purpose of the trial production was to expand a range of high heat transfer and promote turbulence compared with the current nozzle.

Paying attention to mass transfer within gravure ink coated film, drying characteristic of the film was analyzed by numerical solution of a set of equations governing the drying process in which concentration dependencies 0f the diffusion coefficient and the equilibrium vapor pressure were considered.

Applying these analyses. an industrial scale dryer with excellent drying efficiency has finally been developed.