Cast Ceramic Insert Grate Element for Combustion Plants
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Solution Overview
Problem
Grate bars in large combustion plants face high stress and nozzle holes tend to burn up, requiring complete replacement and resulting in maintenance standstills, despite modular designs that only replace the feed element.
Innovation Solution
A grate element with a high-temperature-resistant ceramic insert cast around the nozzle holes, providing secure anchoring and reducing the risk of breakage, allowing for multiple nozzle holes to be formed in one step and anchored within the grate element, which is not exposed to combustion material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional grate bars with nozzle holes are used, then the structure is simple and manufacturing is easy, but the nozzle holes burn out and the component must be replaced
Solution Approach 1:
The patent combines ceramic material for the insert with metallic material for the grate element body. The ceramic insert is cast into the metallic grate element, creating a composite structure that leverages the high-temperature resistance of ceramic while maintaining the structural integrity of metal, thereby preventing nozzle hole burnout and extending service life.
Solution Approach 2:
The ceramic insert is nested within the metallic grate element body. The insert is completely enclosed by the casting, with the metallic material surrounding and protecting the ceramic component. This nesting approach allows the fragile ceramic to be protected while still providing its high-temperature resistant functionality at the critical end face.
2Loss of time
If modular grate bar design is used to replace only feed element, then replacement scope is reduced, but shutdown and maintenance costs still occur
Solution Approach 1:
The grate system is divided into modular grate elements that can be independently replaced. Each grate element is a self-contained unit with its own ceramic insert, allowing individual replacement without affecting other parts of the grate system. This segmentation enables quick swap-out of worn elements, minimizing shutdown time and maintenance costs.
3Reliability
If ceramic insert is exposed to combustion material, then nozzle holes remain open, but the ceramic is fragile and risks breakage
Solution Approach 1:
The ceramic insert is completely enclosed by the metallic grate element body during casting. The metallic material surrounds the ceramic insert on all sides, providing mechanical protection and eliminating the need for special handling of the fragile ceramic during operation. The insert is nested securely within the robust metal structure.
Solution Approach 2:
The ceramic insert is pre-positioned and securely anchored within the grate element body before the component enters service. The casting process permanently fixes the insert in place with anchoring elements, eliminating the need for repeated handling or adjustment during operation and preventing breakage from improper handling.
4Productivity
If multiple nozzle holes are formed in one step, then manufacturing efficiency increases, but the casting process becomes more complex
Solution Approach 1:
Multiple nozzle holes are formed simultaneously in a single casting operation. The ceramic insert contains multiple openings that are created in one step during the casting process, rather than requiring separate operations for each hole. This merging of operations increases manufacturing efficiency while the robust casting process ensures adequate precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution extends the service life of grate elements by preventing nozzle hole burnout and reducing maintenance downtime, ensuring durability and cost-effectiveness through a form-fitting connection of ceramic and steel materials.
Implementation Method 1
a high-temperature resistant ceramic insert comprising an opening is cast into the front of the grate element under all-round enclosure
Implementation Method 2
high-temperature resistant ceramic insert
Implementation Method 3
the ceramic insert can have an anchoring element, in particular a projection and/or an undercut, for anchoring in the grate element
Data Source
Figure 1(a)~1(d)
Figure 2(a)~2(e)
Figure 3a~6b
AI summary
The invention relates to a grate element (1, 11) for a moving grate of a large combustion plant, wherein the grate element (1, 11) has an end-face sliding surface (3) perforated with flow openings (4) for air and/or gases, wherein a high-temperature resistant ceramic insert (5) comprising several openings (6) is cast into the end face of the grate element (1, 11) with all sides enclosing it, and the openings (6) of the ceramic insert (5) align on both sides with openings (7) in the end-face sliding surface (3) of the grate element (1, 11) to form the flow openings (4).