Coating tool

Abstract

This application concerns a tool for coating a monolithic shaped catalyst. The tool is part of a coating station and serves to hold and fix the monolith while coating is progressing.

Claims

1. A coating tool comprising: a first means for reversibly holding and fixing a catalyst monolith to be coated with a washcoat; a second means to control an inflow of the washcoat into the monolith; the second means being attached to the first means such that during the coating process the second means comes into contact with the washcoat before the washcoat reaches the monolith; the second means having the form of a plate comprising holes having, when in use, an inlet side towards the washcoat and an outlet side towards the monolith, and channels providing a communication from the inlet side to the outlet side for the washcoat to flow through, wherein at least some of the channels have a non-uniform channel width along an axis extending in the flow direction whereby the channel width is wider at both the inlet side and the outlet side as compared to a narrowed area between the inlet and outlet sides, and for at least some of the channels, the narrowed area is aligned more closely to the outlet side than to the inlet side.

2. The tool according to claim 1, wherein the narrowed area forms a cylindrical surface at the inner periphery of the channel and is located within a half of the channel that is closer to the outlet side than to the inlet side.

3. The tool according to claim 1, further comprising a disk attached concentrically with the second means, the disk having a smaller diameter than the second means and comprising holes.

4. The tool according to claim 1, wherein at least one hole having a non-uniform channel width is configured to receive a sensor finger.

5. The tool according to claim 1, wherein the first means comprises an inflatable bellow configured to reversibly hold and fix the catalyst monolith via inflation and deflation of the bellow.

6. The tool according to claim 5, wherein the bellow is fixed to the first means by an air-tight engagement at an upper side and a lower side of the first means, and the bellow is open to a lateral side of the first means.

Description

EXAMPLES

(1) By way of a simulation based on the channel design depicted in FIG. 11 a CFD (Computational Fluid Dynamics) calculation was performed using the commercially available Ansys Fluent software package (http://www.ansys.com/Products/Simulation+Technology/Fluid+Dynamics/Fluid +Dynamics+Products/ANSYS+Fluent). The calculation is based on the Navier-Stokes equation.

(2) The results of the calculation made for the channels shown in FIG. 11 are presented by the following table 1.

(3) TABLE-US-00001 TABLE 1 Result (at 1 cm after diffusor): 250 l/h by hole 500 l/h by hole Low viscosity washcoat Prior Art design speed Prior art design speed (Density ~1000 kg/m3) 4% higher. 2% higher Washcoat with higher Prior art design speed Prior art design speed viscosity (Density 6% higher 13% higher ~1600 kg/m3)

(4) As can be seen the velocity with which the washcoat exits the channels is in each case higher than in the case of the inventive channel design. This means that the washcoat exiting the channels has a lower tendency to flatten when introduced into the coating chamber with higher velocity and speed. This is in particular noticeable if the density of the washcoat increases. In FIG. 12 the simulated values for both embodiments are presented within a chart showing the velocity-distribution over the outlet surface of the channels for both scenarios. The velocity at a distance from the surface of 1 cm is always less in the inventive design compared with the design of the prior art channels. This results into a more flattened filling of the coating chamber or more filling speed that can be used with channels of the invention.

NUMERALS

(5) 1 First means (1) 2 Second means (2) 3 Holes with asymmetric width 4 Concentrical area disk 5 Bellow 6 Provision for sensor finger 7 Upper side of bellow attachment 8 Lower side of bellow attachment 9 Clamps 10 Holes of concentrical area disk 11 Monolith bodies before and after coating in coating chamber 12 Applied coating tool 13 Coating chamber 14 Space where washcoat is pumped up and down 15 flap FIG. 1 shows the tool from the monolith (outlet) side FIG. 2 shows top-side view on the tool FIG. 3 displays bottom-side view on the tool FIG. 4 reflects bottom view on tool FIG. 5 shows side cut view of tool FIG. 6 depicts zoomed side cut view of preferred bellow region FIG. 7 depicts zoomed side cut view of preferred bellow region FIG. 8 time saving through application of tool for three different products; pass 1 means that the monolith is coated 1 time; pass 2 indicates that coating is done 2 times FIG. 9 side cut of monolith body coated with diffusor tool FIG. 10 shows part of the coating station with coating chamber FIG. 11 Prior art design of diffusors and inventive design used for calculation FIG. 12 Result of calculation showing preferable behavior of the inventive design over the prior art design