Process for axial skinning apparatus

Patent metadata

Field	Value
Publication number	US-9803523-B2
Application number	US-201414514947-A
Country	US
Kind code	B2
Filing date	Oct 15, 2014
Priority date	Nov 29, 2011
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A process for operating an axial skinning apparatus for continuous manufacture of skinned ceramic honeycomb parts, including:
determining the physical process parameters of the apparatus including:
the rheology of the flowable skin cement; the geometry of the part to be skinned; and the geometry of the annulus gap of the skinning chamber; and
calculating a plurality of dimensionless pressure gradient values (Lambda (Λ)) according to the formula (1):

Λ
=

(

Δ
⁢

⁢
P

)

⁢
R

2
⁢
m
⁢

⁢
L

⁢

(

R
V

)

n

(
1
)

where ΔP, P, R, V, L, and m and n are as defined herein;
plotting a plurality of manifold pressures versus a plurality of part velocities; and
selecting at least one operating window based on the skin quality of a plurality of preliminarily skinned parts.

First claim

What is claimed is:

1. A process for operating an axial skinning apparatus for continuous manufacture of skinned ceramic honeycomb parts, the apparatus comprising: a skinning chamber that receives a source of flowable skin cement and receives a part to be skinned by the cement; and an annulus gap defined by the space between the skinning chamber and the part to be skinned;
the process for operating the axial skinning apparatus comprising:
determining physical process parameters of the apparatus including:
a fluid rheology of the flowable skin cement;
a geometry of the part to be skinned; and
a geometry of the annulus gap; and

calculating a plurality of dimensionless pressure values (Lambda (Λ)) according to the formula (1):

Λ
=

(

Δ
⁢

⁢
P

)

⁢
R

2
⁢
m
⁢

⁢
L

⁢

(

R
V

)

n

(
1
)

where
ΔP is the pressure drop in the initial applied manifold pressure (P) on the flowable skin cement,
R is the radius of the skinning chamber,
V is the velocity of a part traversing the skinning chamber,
L is the axial length of the skinning chamber, and
m and n characterize the fluid rheology of the flowable skin cement according to y equals m times X n ;
plotting a plurality of manifold pressures versus a plurality of part velocities to produce a graph having a plurality of line plots;
skinning a plurality of parts to produce a plurality of preliminarily skinned parts; and
selecting at least one operating window based on the skin quality of the plurality of preliminarily skinned parts, wherein the plurality of dimensionless pressure values (Lambda (Λ)) have at least one critical pressure drop Lambda (Λ cr ), wherein the selected at least one operating window comprises the at least one point that corresponds to at least one critical pressure drop Lambda; and

maintaining operation of the axial skinning apparatus at a pressure value less than the at least one critical pressure drop Lambda (Λ cr ).

2. The process of claim 1 wherein lambda (Λ) depends only on the annulus gap and the fluid rheology of the flowable skin cement.

3. The process of claim 1 wherein the geometry of the annulus gap is a pair of concentric cylinders having a circular or oval cross-section.

4. The process of claim 1 wherein the rheology of the flowable skinning cement is characterized by the m and n values obtained from a log-log plot of viscosity versus shear rate for the plurality of preliminarily skinned parts, where n is the slope, and m represents a shift in at least one of the plurality of line plots given by the equation y equals m times x n .

5. The process of claim 1 wherein the value of the plurality of lambdas (Λ) is from about 10 to about 150.

6. The process of claim 1 wherein the at least one critical pressure drop Lambda (Λ cr ,) is from 150 to 200.

7. The process of claim 1 wherein, in an operating axial skinning apparatus, if the Lambda (Λ cr ) is maintained at less than 150, then the process prevents or reduces skin ripple defects in the skinned ceramic honeycomb parts.

8. The process of claim 1 wherein the skin quality of the plurality of preliminarily skinned parts comprises at least one of:
an absence of bare spots;
absence of skin ripples; and
a dry skin thickness from 0.5 to 1.5 millimeters.

9. The process of claim 1 wherein operating the axial skinning apparatus is accomplished as close to a maximum of the critical lambda value (Λ cr ) but without exceeding it.

Assignees

• Corning Inc

Inventors

• Hagg Ralph Henry
• Harihara Parasuram Padmanabhan
• Singh John Paul Bir
• Vaddiraju Srinivasa Rao

Classifications

• C04B38/0006

  Honeycomb structures (from one or more corrugated sheets by winding or stacking C04B38/0083) · CPC title

• B29C48/92

  Measuring, controlling or regulating · CPC title

• F01N3/0222 Primary

  the structure being monolithic, e.g. honeycombs · CPC title

• B29C48/11

  comprising two or more partially or fully enclosed cavities, e.g. honeycomb-shaped · CPC title

• B29C48/156

  Coating two or more articles simultaneously · CPC title