Page 180 - Chemical Process Equipment - Selection and Design

152 FLUID TRANSPORT EQUIPMENT

140
120
100
80
z
60
40

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'0 IO 20 30 40 50 60 70 80 90 130
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(a)

Curved
Backwardly Radial Forwardly
Curved Blade
s-
First Cost* ............ High Medium Low
Efficiency. ............
Stability of Operation.. . High Medium Low
Poor
Good
Good
Space Required. ....... Medium Medium Small
Tip Speed.. ........... High Medium Low
Resistance to Abrasion.. Medium Good Poor
Ability to Handle
Sticky Materials. .... Medium Good
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Figure 7.24. Performances of fans with various-shaped blades (Green Fuel Economizer Co.): (a) Backward curved blades. (b) Straight radial
blades. (c) Forward curved blades. (d) Comparison of characteristics of the several blade types (Sturtevant).

TABLE 7.6. Specifications of Centrifugal Compressors
Speed Nominal at
Normal Inlet Flow Nominal Polytropic Nominal Polytropic Nominal Maximum Polytropic
Rangea Head per Stage Efficiency No. of
Frame (ft3/min) (H,) blP) Stages" Head/Stage
29M 500-8000 10,000 0.76 10 1 1500
38M 6000-23,000 10,000/12,000 0.77 9 8100
46M 20,000-35,000 10,000/12,000 0.77 9 6400
60M 30,000-58,000 10,000/12,000 0.77 8 5000
70M 50,000-85,000 10,000/12,000 0.78 8 41 00
88M 75,000-1 30,000 10,000/12,000 0.78 8 3300
103M 11 0,000-1 60,000 10,000 0.78 7 2800
110M 140,000-1 90,000 10,000 0.78 7 2600
25MB (H) (HH) 500-5000 12,000 0.76 12 11 500
32MB (H) (HH) 5000-1 0,000 12,000 0.78 10 10200
38MB (HI 8000-23,000 10,000/12,000 0.78 9 81 00
46MB 20,000-35,000 10,000/12,000 0.78 9 6400
60MB 30,000-58,000 10,000/12,000 0.78 8 5000
70MB 50,000-85,000 10,000/12,000 0.78 8 4100
88MB 75,000-130,000 10,000/12,000 0.78 8 3300
"Maximum flow capacity is reduced in direct proportion to speed reduction.
bUse either 10,000 or 12,000ft for each impeller where this option is mentioned.
'At reduced speed, impellers can be added.
(Elliott Co.).