I'm looking at building a forge for a combination of general purpose work and for tempering long items such as swords. I've decided on using an electric blower for the air supply, and already know to use radial/centrifugal type blowers. I've done a bit of searching and have come across information stating to use a blower with a flow rate of about 150-400 cfm, and suitable for anywhere from 1.5 to 6 inches of static pressure. My first question is: Is this information accurate?
To design the forge for general purpose work, would it be easiest to design a forge with long firepot with multiple tuyere "branches" going to separate grates in the bottom of the firepot, or perhaps make one long grate with an air gate just underneath that could slide out to adjust the amount and size of the air blast? Perhaps there are better ideas than this that I couldn't find? With the multiple branches, an air gate on each branch could control the size of the blast, but I'm afraid of uneven heating causing problems for hardening.
The final problem is how much air flow will all this require. Going from what was stated before, for a typical forge an average of 250 cfm could be a basic reference point. With 4 tuyere "branches" or the equivalent thereof, the needed cfm would be more around 1000. Does this sound correct, and if there is any information I missed or anyone has a better idea please let me know!