Monday, October 31, 2011

Inset Stove Design and Testing Part 2


Insert Stove
Design Factors and Testing
Part 2

An Inset Stove called Firewarm

So to recap -


A standard stove is simply a single sealed box. It can be made of iron - steel  -or other fireproof material.  Let us simply call this:


A controllable amount of air comes in one end to feed oxygen to the fire - and hot gasses and smoke goes out the other end and up the chimney. The heat from the fire is dispersed both by radiant and convection means from all sides of the stove.


An Inset or Insert stove, by contrast,  is stuck into the wall or chimney breast and therefore it cannot radiate or convect heat - except from the front. That leaves 5 other surfaces which cannot give out any heat

An Inset Stove has TWO BOXES,  one inside the other. The inside box is a complete stove in and by itself.

The outer box is there for ONE PURPOSE ONLY. It is there to create convection air channels to take the heat from the sides, back, and top of the fire box, and GET THAT HEAT OUT INTO THE ROOM. This box let us call it:


Apart from getting the fire to burn well and fully controllably in BOX NUMBER ONE, an inset stove needs to have a convection air current established in BOX NUMBER TWO (the outer box, in order to take the heat from the back -sides and top of the stove out and into the room.


What we are testing:

Is the burn rate of the fire fully controllable? This is a basic test for any type of solid fuel stove.

This test is really easy to establish. When the fire is fully lighted and burning really hot, simply turn down both the primary and secondary air controls fully.

The fire should immediately begin to dim down and within five minutes or so should be burning a dim red. After an hour or so - if the stove is in very good airtight condition, the fire should go out completely.

Most stoves are not completely airtight - so the fire may not completely die down but may continue to burn. However, it should only burn at a really very low rate!!

If it continues to burn at a faster rate, you have a faulty stove. The problem could be one of several things. Here are a few to think about:

(a)    Poor door seals.
(b)    Poorly fitting air vents.
(c)    Joints in the stove sections not properly sealed.
(d)    A crack or break in the stove wall. This could happen in manufacture, shipping or fitting.
(e)    And - of course, the possibility of bad design!!

In the next post I will publish a simple test that is very easy to do, and is specific to inset stoves.


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