HEAT RETENTION BALLS FOR NON FERROUS METAL MELTING
CONCEPT :
The Concept of this invention is to Increase the retention time of the required temperature for a molten nonferrous metal. The normal practice of melting In a nonferrous foundry is done in two stages.
This is a process of heating the scrap /ingot to a required temperature and conduct treatment of metals to remove their oxides, purify, removal of gas, Refine, etc which is called hot metal treatment which is processed at least temperature of 150 degrees more than pouring/ casting temperature
This furnace is maintained at the required pouring/ casting temperature and molten metal from melting is transferred to this furnace. The holding is done to homogenize, remove slag( dirt) , ensure the temperature is under control during casting. The temperature uniformity required is of very big importance to achieve good sound casting. There are electrical heaters/ Gas burners to replenish the heat loss during casting ( The casting is performed on more than 100 molds at a stretch in gravity casting, and thousands in pressure die casting, etc).
MY INVENTION
I wanted to improve the working conditions in a nonferrous alloy foundry. I wanted to address this problem. Aim was to improve the Temperature holding conditions with small temperature variation even during delay of pouring or casting which saves lot of power. I was looking for a material which can work as a flask for melting crucibles/ holding crucibles. I came across a material which can withstand heat for a long duration and doesn’t react with nonferrous metal.
Discussion
I remember the story for invention of foot wear. Funny isn’t it. I have to narrate once there was a king in those days there were no foot wears. The court yard and palace had protected pathway using Buffalo skin. There was no mess during rainy season. Once king started walking on streets his kingdom he realized that his leg was messy due to mud on the open place. He wanted to give a solution to his people for a common man. He announced to bring maximum amount of buffalo skin cover his whole kingdom. There was shortage of skin and he was worried how to solve the problem. Meanwhile there was a common man gave an idea ‘ why don’t we cover our foot instead covering the whole earth ? ‘ he stitched a foot wear to King . King wore the footwear and was very happy. He gave him lot of gifts and galore. My invention has a small similarity with this story
Invention
The concept is to retain the heat of the molten metal by using a material which has a very high ' Heat content' or ' Enthalpy' heat retention from the center most part of the molten metal ensure very high temperature retention capacity.
I have taken trials on small scale and achieved very good results.
- We have taken trial in a Pressure die casting unit. The workers used to work for 16 hours a day right from morning 6 AM to night 8PM. The time taken for melting 300Kg aluminum is minimum of 4 hours. There was a production loss of 4 hours every day.
- We have introduced heat retention balls . At the end of the shift these balls were placed in the molten metal of the holding furnace. Next day morning the temperature of the molten metal was reduced only by 100 Deg C which was recovered in 1 hour heating.
- The production loss of 4 hours was converted to 1 hour only
- The power savings is up to 30 to 40% on electrical heating furnaces
- The Fuel savings on gas fired furnace is up to 25 to 30%
Advantage of the invention
- Huge power savings on melting and also on holding furnaces
- Temperature variation is only /- 15 Deg C over 2 hours of holding
- The Holding furnace can be made with less bulky and easy to carry to pour in molds especially in sand casting and gravity die casting
