MIL-HDBK-1004/10

where

Y

=

10 years

S

=

1.0 lbs/A yr

E

=

0.50

I

=

15.2 A

W

=

10 x 1.0 x 15.2/0.50 lb

W

=

304 pounds

f)

Minimum weight of riser anode material:

W

=

YSI/E

where

Y

=

10 years

S

=

1.0 lbs/A yr

I

=

3.62 A

E

=

0.50

W

=

10 x 1.0 x 3.62/0.50 lb

W

=

72.4 lb

g)

Radius of main anode circle:

= (DN)/2(B+N)

r

where

D

=

56 feet

N

=

10 (assumed number of anodes)

r

=

56 x 10/2(3.1416 + 10)

r

=

560/26.28

r

=

21.3 feet, use 22 feet

h) Spacing of main anodes. Generally the distance from the anode

to the tank wall and tank bottom is about equal; this distance should be about

one-half the circumferential distance between anodes.

(1)

Circumferential spacing:

= (2Br)/N

C

where

r

=

22 feet (radius of anode circle)

N

=

10 (assumed number of anodes)

C

=

2 x 3.1416 x 22/10

C

=

13.8 feet, use 14 feet

(2) Cord spacing is approximately the same as circumferential

spacing:

14 feet will be used (see Figure 98).

159

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