Those Anti-Explosion Louvers are not a new design.
They were standard item on Riteway Stoves from back in the 1970's and 80's.
Riteway Stoves were a favorite of the Amish Community right up until Riteway went out of business.
It stands to reason why there are a lot of similarities in DS Machine and Hitzer's stove line-ups from the Good ole Riteways.
I have a pair of Louvers from a 80's model #37 Riteway. As was mentioned...same dimensions as a brick...to take ones place in the stove and channel air from below up to top of fire.
There were some smart fellows in the 1970's that figured these out.