Rapid drying of ceramic greenwares

Patent metadata

Field	Value
Publication number	US-10173933-B2
Application number	US-201414230756-A
Country	US
Kind code	B2
Filing date	Mar 31, 2014
Priority date	May 6, 2013
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

Systems and methods for rapid drying of ceramic greenwares having a high graphite content are disclosed. The methods include employing microwave drying to bring the dryness of the ceramic greenware to a first select dryness and then employing close-coupled hot-air drying to bring the dryness to the final target dryness. The judicious use of close-coupled hot-air drying reduces end defects due to unevenness in the microwave drying process while also substantially speeding up the drying process. Various configurations for and combinations of microwave drying and close-coupled hot-air drying are disclosed.

First claim

What is claimed is:

1. A method of drying an extruded ceramic greenware having an array of open longitudinal cells and opposite input and output ends, comprising:
drying of the ceramic greenware to form a partially dried ceramic greenware having a dryness of 10% or less, wherein the drying includes performing a first close-coupled hot-air (CCHA) drying with a coupling distance Δx having a value in a range defined by −2″≤Δx≤10″ and the first CCHA drying is performed while the ceramic greenware is disposed horizontally;
drying the partially dried ceramic greenware to a target dryness of at least 98% to form a dried ceramic greenware, wherein drying the partially dried ceramic greenware includes performing at least one of microwave drying and at least a second CCHA drying; and
wherein the ceramic greenware from 0% to 10% dryness has a dielectric constant ε=ε′+iε″ that defines a loss tangent tan(δ)=ε″/ε′≥0.05.

2. The method of claim 1 , wherein the CCHA drying system comprises an air-guide device with one or more channels, and wherein the method further comprises directing the hot air through the one or more channels.

3. The method of claim 1 , wherein passing CCHA through the ceramic greenware from the input end to the output end comprises at least one of blowing and vacuuming.

4. The method of claim 1 , including performing the acts therein so that the dried ceramic greenware has a reduced number of end defects as compared to a number of end defects formed when carrying out the drying process using only microwave drying.

5. The method of claim 1 , wherein the ceramic greenware has a diameter D in the range 3″≤D≤20″.

6. The method of claim 1 , wherein the longitudinal cells are defined by cell walls having a thickness TH in the range 1 mil≤D≤15 mils.

7. The method of claim 1 , wherein the ceramic greenware contains graphite and a total amount of inorganics, and wherein the amount of graphite is greater than 5 wt % measured relative to the total amount of inorganics.

8. The method of claim 1 , wherein drying the partially dried ceramic greenware includes performing at least one microwave drying.

9. The method of claim 8 , wherein the performing of the at least one microwave drying includes performing multiple microwave drying steps sequentially in multiple microwave applicators.

10. The method of claim 1 , wherein the coupling distance Ax has a value in a range defined by −2″≤Δx<0″.

11. The method of claim 1 , wherein the first CCHA drying comprises directing hot air into the ceramic greenware using an air-guide device that comprises a tube.

12. A method of drying an extruded ceramic greenware having an array of open longitudinal cells, an input end, and an output end, the method comprising:
contacting an air-guide device with at least one of the input end and the output end of the ceramic greenware to form a coupling distance Δx between the air guide and the ceramic greenware having a value of Δx<0″; and
flowing hot air through the air-guide device and into the ceramic greenware to dry the ceramic greenware,
wherein the contacting and the flowing are performed while the ceramic greenware is disposed horizontally.

Assignees

• Corning Inc

Inventors

• Cutler Willard Ashton
• Feldman James Anthony
• George Jacob
• Halder Amit
• Paramonova Nadezhda Pavlovna
• St Clair Todd Parrish

Classifications

• F26B2210/02

  Ceramic articles or ceramic semi-finished articles · CPC title

• C04B38/02 Primary

  by adding chemical blowing agents · CPC title

• C04B2235/61

  Mechanical properties, e.g. fracture toughness, hardness, Young's modulus or strength · CPC title

• B28B11/243

  Setting, e.g. drying, dehydrating or firing ceramic articles (B28B11/242 takes precedence) · CPC title

• C04B35/20

  rich in magnesium oxide {, e.g. forsterite (C04B35/195 takes precedence)} · CPC title