Gallery, Projects and General > The Design Shop

heating elements, a better way?

(1/2) > >>

shipto:
If anyones noticed I am currently trying (with limited success at the moment) to build a electric furnace based on the gingery lil Bertha design.
I was thinking today about the way the element is mounted in grooves in the side walls which is pretty much standard as far as i can tell even with commercial units, Is this the best way however? I was thinking that the element mounted at the bottom would be better then I thought it would be much better if the element had a gap underneath and around the sides, this should create a recycling convection effect and the temps should rise much quicker and more evenly throughout the furness.
Sadly I am far behind the self imposed timetable I have set myself and dont have the time to look more into this so I am throwing it out there in case anyone else wants to have a go.

hermetic:
Hi Shipto, have you any pics? are you using solid cooker type elements or wire wound fire type. I have seen small kilns and alloy melters with both. With the cooker ring type element, they are underneath the crucible set into a fireclak moulding so that the crucible sits on the moulding, not the element. With the wire coils, they are fitted in slots in the side walls of the furnace, set back into the refractory and sometimes have refractory pencil made from porcelain or similar inside the coil to support the elements, and prevent them sagging out of the slots when they are hot, any help?

shipto:
Hi hermetic the pictures of my efforts are in the "metal stuff" section, this is just something I was mulling over today while at work and I thought I would post the idea I know its not a new idea convecter heaters use this principle on a much bigger scale after all.
I was thinking some kind of ceramic housing for the element with feet to hold it off the ground of the furnace chamber.

PK:
In my little electric furnace, I suspect that a lot of heating takes place by radiation. 

BillTodd:
As suggested by PK above, the vast majority of heat is transferred by radiation, not by convection.  The vacuum fernaces at work  (obviously) have no convecting gas in them when they're on yet heat up just fine.

The heat transfer is then a function of surface area, so heating coils on all faces is better.

If you want faster heating, you'll need to reduce the mass being heated (for a given input power). One way is by induction ,where the heat is primarily generated in the part directly .

Navigation

[0] Message Index

[#] Next page