U-Shaped Grate Bar Cooling Channel Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing grate bar designs for thrust grate furnaces face issues with inefficient cooling due to clogged air outlets and uneven temperature distribution, leading to local destruction and complex manufacturing processes.
Innovation Solution
A grate bar design featuring closed channels on the underside with undirected primary air flow, which directs cooled air through collecting ducts transverse to the grate bar, preventing clogging and ensuring even cooling across adjacent bars, while cooling ribs enhance thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If primary air outlets are provided on the front area of the grate bar, then cooling effect is improved, but the outlets become clogged by liquid slag blocking the gap
Solution Approach 1:
The grate bar is divided into multiple segments with individual cooling channels. Each cooling channel is equipped with separate control mechanisms, allowing selective operation of different segments. This segmentation prevents complete blockage from affecting the entire grate bar, as other segments can continue to function independently.
Solution Approach 2:
The grate bar incorporates movable components including adjustable air outlets and flexible cooling channels. The air outlets can be dynamically adjusted in position and opening size to optimize cooling while avoiding slag accumulation zones. Flexible channels can adapt their configuration to maintain flow paths even when partial blockages occur.
2Temperature
If cooling fins are added to the underside of the grate bar, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling fins are integrated directly into the grate bar structure rather than being separate attachments. The fins form an integral part of the grate bar's cross-section, combining the structural support function with the heat dissipation function in a single unified component, thereby reducing overall device complexity.
Solution Approach 2:
The grate bar structure serves multiple functions simultaneously: it provides mechanical support for the grate, acts as a heat transfer surface through integrated cooling fins, and incorporates cooling channels for air flow. This multi-functionality eliminates the need for separate cooling devices, reducing overall system complexity.
3Temperature
If serpentine tube cooling is used, then cooling coverage is improved, but manufacturing complexity increases significantly
Solution Approach 1:
Instead of using a single complex serpentine tube, the cooling system is segmented into multiple straight or simple curved channels distributed throughout the grate bar. Each channel is independently formed using standard manufacturing processes, avoiding the need for complex tube bending and welding operations required for serpentine configurations.
Solution Approach 2:
The cooling channel geometry is optimized by changing from a serpentine configuration to a series of parallel or radially arranged channels. This parameter change in channel arrangement simplifies the manufacturing process while maintaining adequate cooling coverage through increased channel density and strategic positioning.
4Temperature
If air exits through nozzle-like openings, then cooling target is improved, but burning effect increases fuel consumption
Solution Approach 1:
The air outlet characteristics are made non-uniform across different locations on the grate bar. Areas with higher thermal loads have larger or more numerous outlets, while cooler areas have smaller outlets. This local differentiation optimizes cooling efficiency while minimizing unnecessary air flow that would cause burning effects in already-cooled regions.
Solution Approach 2:
The air outlets are operated in a periodic or pulsing manner rather than continuously at full capacity. The outlet openings are cyclically adjusted to match the periodic nature of thermal loading on the grate bar, providing cooling only when and where needed, thereby reducing overall air flow and preventing excessive burning effects.
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 optimizes cooling by preventing burner effects and blockages, ensuring effective air distribution and improved mechanical strength, with enhanced thermal management and reduced risk of local overheating.
Implementation Method 1
The combustion air, which is blown as so-called primary air through the combustion grate into the fuel bed resting on it, is used to cool the grate bars of combustion grates
Implementation Method 2
the underside of the grate bar can be provided with cooling fins that are blown on by the primary air
Data Source
Figure 1
Figure 2
Figure 3~7
AI summary
The invention relates to a grate bar (4) and grate (3) for a push grate combustion system, wherein the grate bar has a U-shaped profile with a back (1) and side surfaces (2) and is air-cooled, characterized in that in the front area of the grate bar (4) at least one closed channel (6) for primary air (7) runs substantially parallel to the end face (8), which has a lower opening (10) for the inlet of primary air (7) and an upper opening (11) for the outlet of primary air (7), wherein the upper opening (11) opens into a collecting channel (12) running transversely to the longitudinal axis of the grate bar (4) and exits through this channel via an opening in the side surface (2) of the grate bar (4).The solution according to the invention has the advantage that the primary airflow, which comes undirected from the funnel, is guided as a directed flow for optimal cooling on the underside of the grate into the particularly highly stressed area of the grate bar and the grate itself, and the subsequent discharge of the heated primary air into the combustion bed is such that undesirable combustion effects on the upper side of the grate bar are avoided. Furthermore, clogging of the openings of the collecting channels is prevented.