Mark,
The "coal feeder" you are refering to is often called a stoker. Use google and search on "coal stoker" Based on your question, you must be fixing up some kind of a small antique boiler ?
New coal fired boilers are all of the watertube design and they are fed pulverized coal....... ( and..um ... they are huge)
Get the "Steam" book by Babcock & Wilcox........ cheap older copies are available on e-bay and "half priced books.com" ( or something like that). This book has design details of the ancient stokers that your firetube boiler requires.......
How about some more details ?
You are not trying to start up some old boiler in India or Iraq or something........ are you ?
MJC