12 
BULLETIN 894, IT. S. DEPARTMENT OF AGRICULTURE. 
The spray-chamber walls should be braced with piers from 4 to 5 
feet apart, carrying the steel support of the rails. 
Expansion Jo/ntiriS/ob 
'•><* "oof"? >/, 
'ollow Ttfe 
Pitch Roof to Gutter- * V* Foot- 
%e.inrorced Concrete Joists^ ? 
n 
Fig. 5.— Typical cross section. Tile walls, concrete spray chamber, concrete and tile roof. Flat open piling. 
No paint or other coatings or preservatives should be used in the 
spray chamber, as the hot water and steam will cause small particles 
to wash down to the well and make trouble in the pumps and sprays. 
BAFFLE BOXES. 
The function of the baffle boxes is to remove any fine spray or 
mist from the air coming down the spray chamber before it returns 
to the coils. 
The boxes are usually built of wood, but in some cases metal 
has been used. Metal is liable to rapid deterioration, on account 
of the acid fumes given off by certain species when seasoning. 
Even copper will disintegrate very rapidly. Cypress, Douglas fir, ^ 
redwood and pine have proved most suitable, and white cedar and 
western red cedar are satisfactory. 
The baffles should be built up in interchangeable sections, dressed 
1-inch lumber fastened with brass screws being used. The boxes 
should fit between the supporting piers tight against the spray 
chamber wall, but should not be fastened in place. (Fig. 6.) 
