Values of coefficient of entry Ce

Typical values of Ce are shown in Figures 3.46 to 3.52.

О

Diametir mm

C.

100

765

150

-745

200

— 735

250

• 725

At about 20 m/s in duct. Ca is less at lower velocity Figure 3.46 Ce for plain open ended duct

Open

Flanged

D mm

Mouth mm

L mm

C.

C.

75

75*225

150

809

849

100

100 x 300

200

854

865

125

125 x 375

225

814

844

200

200 x 600

300

785

804

Figure 3.50

подпись: figure 3.50Ce for rectangular hoods ratio 1 : 3

Diameter mm

C.

100

86

150

• 855

200

•835

250

•81

Values of coefficient of entry CeAt about 20 m/s in duct. Ce is less at lower velocity Figure 3.47 Ce for flanged open ended duct

Open

Flanged

0 mm

Mouth mm

L mm

C.

100

100×125

125

.849

89

150

190 x 250

175

• 838

865

Ј

подпись: ј

Angle 0

подпись: angle 0

Figure 3.51 Ce for rectangular hoods ratio 3 : 4

подпись: figure 3.51 ce for rectangular hoods ratio 3 : 4

Round

Square

Included angle 6

Pipe 200 mm dta

Pipe less than

Pipe 200 mm

Pipe less than

Or largtr

200 mm dia

Square or larger

200 mm square

20-

.96

■91

• 94

89

40*

• 99

• 93

• 95

90

60′

•98

• 92

• 94

88

75*

• 96

• 91

• 93

• 87 I

90*

• 95

• 90

•91

85

120*

• 91

• 86

• 87

• 82

1 150*

86

• 82

• 83

• 79 ‘

Figure 3.48 Ce for tapered hoods

Values of coefficient of entry Ce

0 mm

Hood mm

C.

150

Plain with 165 x 50 wheel

• 80 without wheel — 725 with wheel

250 mm—►

For average hoods including the obstruction of grinding or buffing wheel take Ce at • 71

Figure 3.52 Ce for grinding wheel hoods

Posted in Fans Ventilation A Practical Guide


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