Specifying CRV®
For the convenience of engineers, architects and designers in writing CRV® specifications, Cheng Fluid Systems suggests the following :
The Cheng Rotation Vane (CRV® ) must be located right at but no further than one pipe diameter away from the elbow's inlet. With this arrangement there will be a uniform velocity profile with no downstream residual rotation.
Depending on the application, the CRV® is designed to address specific flow requirements such as velocity distribution, separation (which has accelerated and reverse flows), noise, vibration, erosion, elimination of turbulence, and pressure drop reductions.
Materials of Construction
The CRV® can be manufactured from most commercially available materials, pipe diameters, pipe schedules and end connections. N-stamped units are available for nuclear applications. Special internal coatings and finishes are also available.
Applications
For the convenience of engineers, architects and contractors in writing CRV® specifications, please reference the application diagrams provided below.
Dimensions
CRV® - standard unit dimension in 2" to 12" sizes are shown in Table 1 below. Special length or design CRV® s can be quoted on request.
Pipe Fitting Geometry
When specifying a CRV® , it is critical that the CRV® matches the geometry of the fitting to which it will be attached. The fitting schedule (wall thickness) and type of fitting must be specified. We must know if the CRV® will be used with a long radius or short radius elbow. Incorrect fitting specifications will result in poor performance because the angle of the CRV® is very sensitive to the fluid path traveled in the elbow. To assist in the proper specification of a CRV® , standard common fitting types, their nomenclature, and dimensions are shown in Figures 11-15 (Table 2) for both short and long radius applications.
TABLE 1
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Pipe Dia. (Nom.) |
Standard Stock CRV ® Units |
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Beveled ends (Fig. 9) |
150# RFSO Flanges (Fig. 10) |
150# RFWN Flanges (Fig. 10) |
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A |
B |
C |
D |
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2" |
2.00" |
2.50" |
7.00" |
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3" |
3.00" |
3.75" |
8.50" |
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4" |
4.00" |
4.75" |
10.00" |
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6" |
6.00" |
6.75" |
13.00" |
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8" |
8.00" |
8.75" |
16.00" |
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10" |
10.00" |
10.75" |
18.00" |
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12" |
12.00" |
12.75" |
21.00" |
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>14" |
Consult Factory |
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TABLE 2
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Pipe Dia. (Nom.) |
Ou tside Pipe Diameter |
90° ELBOW |
45° ELBOW |
180° ELBOW |
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Short Radius (Fig. 11) |
Long Radius (Fig. 12)
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Long Radius (Fig. 13)
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Short Radius (Fig. 14) |
Long Radius (Fig. 15)
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E |
F |
G |
H |
J |
K |
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2" |
2.375" |
2" |
3.0" |
1.375" |
4" |
6" |
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3" |
3.500" |
3" |
4.5" |
2.000" |
6" |
9" |
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4" |
4.500" |
4" |
6.0" |
2.500" |
8" |
12" |
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6" |
6.625" |
6" |
9.0" |
3.750" |
12" |
18" |
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8" |
8.625" |
8" |
12.0" |
5.000" |
16" |
24" |
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10" |
10.750" |
10" |
15.0" |
6.250" |
20" |
30" |
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12" |
12.750" |
12" |
18" |
7.500" |
24" |
36" |
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>14" |
Consult Factory |
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