Sand Core Coating with Tar Reducing Agent for Gas Drain Clogging
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Solution Overview
Problem
In die casting, the incomplete combustion of organic binders in sand cores leads to tar and soot generation, causing clogging in gas drains and defects in cast products, and existing solutions complicate the structure with additional components like duct plugs and heating devices or blades.
Innovation Solution
Incorporating a tar reducing agent as an oxidant in the outermost layer of the coating layer, which decomposes tar into carbon monoxide, carbon dioxide, and water upon heat from the molten metal, preventing tar generation and adhesion to gas drains, thus simplifying the gas drain structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sand core with organic binder is used in die casting, then the core body can be formed and maintained, but incomplete combustion of the organic binder generates tar and soot that clog gas drains
Solution Approach 1:
The patent converts the harmful tar and soot generated by incomplete combustion into beneficial combustion products. By introducing an oxygen supply member that provides oxygen to the combustion zone, the incomplete combustion is transformed into complete combustion, converting harmful tar/soot into harmless low molecular gases (CO2, H2O) that can be safely discharged through the gas drain.
Solution Approach 2:
The oxygen supply member acts as an intermediary that mediates between the organic binder combustion and the gas discharge system. It supplies oxygen directly to the combustion zone, enabling complete combustion without requiring external air supply, thus preventing tar and soot formation that would otherwise clog the gas drain.
2Object-generated harmful factors
If duct plugs or heating devices are added to gas drains to burn tar, then tar clogging is prevented, but the structure becomes complicated
Solution Approach 1:
The patent extracts the oxygen supply function from the external environment and places it directly within the combustion zone through the oxygen supply member. This eliminates the need for complex external tar removal systems like duct plugs or heating devices, as the complete combustion is achieved internally at the source of tar generation.
Solution Approach 2:
The sand core system becomes self-sufficient for complete combustion by incorporating the oxygen supply member within the core body. The system serves itself by providing oxygen directly where needed, eliminating the need for external assistance from complex gas drain modifications or additional tar burning devices.
3Speed
If pressure is reduced in the cavity to discharge gas, then gas can be discharged, but air and oxygen cannot be supplied from outside to the cavity
Solution Approach 1:
The oxygen supply member performs preliminary action by storing and supplying oxygen directly to the combustion zone before external air can be supplied. This pre-positioned oxygen ensures complete combustion occurs even when the cavity is under reduced pressure and external air supply is blocked, maintaining both gas discharge capability and sufficient oxygen availability.
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 tar reducing agent effectively prevents tar and soot adhesion to gas drains, reducing defects in cast products and eliminating the need for additional tar removal members, resulting in a simplified gas drain structure and improved product quality.
Implementation Method 1
a tar reducing agent which can decompose tar into carbon monoxide, carbon dioxide, and water by receiving heat
Implementation Method 2
decompose tar into carbon monoxide, carbon dioxide, and water by receiving heat from the molten metal
Data Source
AI summary
In the sand core 10, the tar reducing agent is included in at least the second coating layer 13, which is the outermost layer, of the coating layers 12 and 13. Thus, the tar, which may be generated from the core body 11 and the coating layers 12 and 13 which are positioned thereinside, can be decomposed into low molecular gases (carbon monoxide, carbon dioxide, water, and the like) by heat of the molten metal. As a result, generation of the tar from the sand core 10 to the outside can be prevented. In this case, since the layer which includes the tar reducing agent is the second coating layer 13 which directly contacts the molten metal, the second coating layer 13 can directly receive the heat of the molten metal, and the tar generation prevention effects can be thereby remarkably obtained. Therefore, generation of defects in cast products which may be caused by clogging in the gas drain can be prevented, and structures of the gas drain of the die and the surroundings thereof can be simplified.