222 U. S. BUREAU OF FISHERIES 
is 6 feet 6 inches. The width can be approximated as follows: About 27.5 
square feet of free area for passage of the required amount of air is needed. If 
it is assumed that 50 per cent of the cross section occupied by the truck (top of 
tunnel to bottom) is free area, this amounts to 2.67 6.50.5, or 8.7 square feet. 
There must be provided, then, on the sides of the trucks, 18.8 square feet of free- 
65 2, or 2.80 feet of 
width. The baffles hinder air movement somewhat, so let it be assumed that the 
tunnel must be 3.5 feet wider than the trucks, or 6 feet 2 inches in all, inside 
dimensions. The free area should be spaced equally on both sides of the trucks. 
The outside dimensions of the tunnel are about 42 feet by 6 feet 8 inches by 7 
feet high. 
Space occupied by unit.—Total length is about 42 feet, width about 30 feet, 
and height 8 feet. 
area. Since the tunnel is 6.5 feet high, this amounts to 
ESTIMATE OF EQUIPMENT AND FUEL REQUIREMENTS FOR PREPARING 
MAINE QUARTER-OIL AND THREE-QUARTERS MUSTARD FISH 
COOKING UNIT USING INDIVIDUAL FLAKE CARRIERS 
Quantity of fish to be handled—Three hogsheads (3,600 pounds) of ‘round,’ 
quarter-oil fish on the flakes, or 4 hogsheads (4,800 pounds) if the ‘‘eut”’ portion 
only is cooked. 
Number of flakes required for cooker.—Data used: Fish in cooker 15 minutes; 
weight of fish per square foot of surface 1 pound, or 6.25 pounds per 30 by 30 
inch flake. Flakes required, Ux = 144. 
Heat required by cooker —Calculations made on a per-hour basis. Data used: 
Temperature of fish, flakes, and other ironwork entering cooker 40°, leaving 275° 
for all ironwork and 220° for the fish; weight of flakes 9 pounds each and of carrier 
and chains for each flake 23 pounds; specific heat of iron 0.13, of water vapor 
at 275°, 0.47, and of fish 0.8; latent heat of evaporation of water at 212°, 970 
B. t. u.; maximum weight of fish to be handled, 2 pounds per square foot of flake 
surface, or 12.5 pounds per flake. However, for calculating the heat required 
for evaporating water, a maximum weight of 1.3 pounds per square foot of flake 
surface, or 8.125 pounds per flake, with a 25 per cent loss in weight due to evapora- 
tion, is assumed; and for calculating heat loss from cooker housing it is assumed 
that the housing is 11.5 feet high, 3.5 feet wide, and 38 feet long, outside dimen- 
sions (1,140 square feet of exposed surface, not including ends), with a loss of 
0.5 B. t. u. per square foot per hour per degree difference in temperature between 
the air inside and outside of the cooker, the temperature gradient being 275°, 
less 40°, or 235°. 
Heat required for heating the iron is 4144322385 X0.13, or 563,098 
B. t. u.; for heating the fish, 4 144 12.5 1800.8, or 1,036,800 B. t. u.; for 
evaporating water and heating the evaporated water from 220 to 275°, 4144 
8.125X0.25X970, plus 4X1448.125x0.25X55X0.47, or 1,165,144 B. t. u.; 
and for loss through cooker housing, 1,140 0.5 X 235, or 133,950 B. t. u.; giving 
a total of 2,898,992 B. t. u. 
Air supply required for cooker —Data used: Temperature air entering cooker, 
312.5°; drop in cooker, 75°; and cubic feet dry air required to give one B. t. u. 
‘ : - a ee : 3 . 2,898,992 x 76 ; 
in dropping 1° at 275°, 76. Air required is - ae » or 2,937,645 cubic 
feet per hour, or 48,961 cubic feet per minute. 
Size of cooker required.—It is assumed that the flakes pass from one end of the 
tunnel to the other 12 times—6 times in each direction; that the tunnel is 3 feet 
wide and 11 feet high, inside dimensions, giving a cross section of 33 square feet; 
and that the flakes, fish, chains, flake carriers, and drip pans take up 8 square 
feet, leaving 25 square feet, or 75.8 per cent of the total cross section, free area. 
This free area will handle 50,000 cubic feet of air per minute at a velocity of 
2,000 feet per minute. In each of the 12 runs there will have to be 12 flakes. A 
tunnel 38 feet long will handle this number of flakes easily. 
Amount of air to be recirculated.—It is assumed to be at least 90 per cent. A 
similar calculation to that given on page 220 will show this to be true. 
Total heat required.—It is assumed that heat losses through housing for intake 
and recirculation ducts, furnace, biower, and other parts of equipment is twice 
the amount for the cooker housing—2X 133,950, or 267,900 B, t. u.; and that 

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