Curved Furnace Grate Element Cooling for Front Tip Wear
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Solution Overview
Problem
Existing plate-formed grate elements in combustion furnaces suffer from excessive wear at the pointed front tip edge due to aggressive fuels and high heat, leading to plastic deformation and corrosion, which reduces their service life and requires frequent maintenance.
Innovation Solution
The grate elements feature an outwardly curved front wall with a varying nominal wall thickness of less than ±35%, ensuring more efficient cooling fluid distribution near the front tip edge, and a restricted cross-sectional flow area in the internal cooling fluid channel to enhance cooling efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the front tip edge is made pointed to maintain clearance with neighbouring grate elements, then the predetermined clearance is maintained, but wear and plastic deformation increase due to concentrated stress and heat
Solution Approach 1:
The front wall is designed with outward curvature instead of being straight, and the front tip edge is rounded instead of pointed. This curvature distributes the contact stress and heat over a larger area, preventing concentrated wear and plastic deformation while still maintaining the necessary clearance with neighbouring grate elements during pivoting movement.
2Reliability
If cooling fluid channels are added to reduce temperature and wear, then service life is extended, but device complexity increases
Solution Approach 1:
The cooling fluid channels are integrated directly into the grate element structure itself, merging the cooling function with the structural component. The channels are formed within the body of the grate element, eliminating the need for separate cooling systems and reducing overall device complexity while effectively reducing temperature and wear.
3Reliability
If the front wall is made thicker to reduce wear, then wear resistance improves, but manufacturing precision requirements increase due to varying wall thickness
Solution Approach 1:
The front wall features outward curvature that creates varying local thickness, with greater thickness at critical areas experiencing higher wear and heat. This local quality variation optimizes wear resistance where needed most while maintaining manufacturability, as the curved profile can be formed through standard manufacturing processes without requiring extremely tight thickness tolerances throughout.
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
This design results in reduced wear and plastic deformation, extending the service life of the grate elements by maintaining the front tip edge temperature below 300°C, compared to the prior art's 900°C, and preventing weak areas that could cause tension buildup.
Implementation Method 1
an internal front cooling fluid channel having an inlet end and an outlet end and extending along the front end of the plate-formed grate element
Implementation Method 2
maintaining the front tip edge temperature below 300°C
Implementation Method 3
the outwardly curved front wall has a nominal wall thickness varying by less than ±35 percent, ensuring more efficient cooling fluid distribution near the front tip edge
Data Source
AI summary
The plate-formed grate element (1, 2) has a top wall (12), a bottom wall (13), a front end (14) and a back end (15). The front end has a lower inwardly curved wall portion (16) adapted to maintain a predetermined clearance with a back tip edge of a corresponding grate element. An internal cooling fluid chamber (18) includes an internal front cooling fluid channel (19) extending along the front end (14) of the grate element. The grate element has an outwardly curved front wall (22) having a nominal wall thickness varying by less than ±35 percent and extending from the top wall of the grate element to the lower inwardly curved wall portion of the front end, and a front tip edge (23) of the front end is formed by the outwardly curved front wall at its connection with the lower inwardly curved wall portion.