Baffles in arch

[buxtonboiler]

I showed a friend my arch the other day, and he asked why there aren't any baffles to help hold the heat and flames in like in a woodstove. I have never seen an arch with baffles. Anyone have any thoughts on this?

[vtsnowedin]

Wood stoves are designed to give a slow even heat out of each load of fuel. Baffles and air tightness or air control are an aid to that end. An evaporator on the other hand is designed to transfer the maximun amount of heat from the fire to the sap in the shortest amount of time. Baffles in an arch are used to push heat and flames up into raised flue pans but other than that anything that restricts the flow of the hot gasses in an arch would be pointless. An arch designer that has excess heat in his flue gasses just makes the pans longer to wring out this heat before it gets away up the stack.

[KenWP]

On my arch for the flue pans I made provision to put a metal baffle that can be taken out or made higher or shorter depending on how it works if at all. Its in the middle of the flue as I figured that the hot gasses would try and sink down about there and I am trying to drive them back up towards the bottom of the pans and the drop tube flues.
Does this make any sense to do this.

[maple flats]

Every evaporator I have seen or had has been designed to force the heat up to the pans. My fire box has a back wall, then a ramp pushing the heat up and finally a very thin space between the arch below and the flues to make the heat pass through the flues. This regardless of whether it is raised or drop flue or even flat pan. In some way the arch or bricking calls for designing it to push the heat to the pans. No need for a baffle, in fact one would be counter productive. Baffles would only help on a slow burn to hold heat in until it can be radiated off. That is not what we need nor want in an evaporator.