Rosemount 1495, Руководство по установке и эксплуатации

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Reference Manual
00809-0100-4792, Rev CA
August 2010
Rosemount 1495, 1496
B-10
a S is the separation between the two bends measured from the downstream end of the curved portion of the upstream end to the upstream end of
the curved portion of the downstream bend.
b Bends should have a radius of curvature equal to 1.5D.
c Column A for each fitting gives lengths corresponding to “zero additional uncertainty” values (see 6.3.2.3.2).
d Column B for each fitting gives lengths corresponding to “0.5% additional uncertainty” values (see 6.3.2.3.3).
e
n
is the number of diameters such that the upstream end of the 19-tube bundle flow straightener (1998) is situated 1D from the downstream end of the
curved or conical portion of the nearest fitting. It is desirable that the length between the upstream end of the 19-tube bundle flow straightener (1998)
and the downstream end of the curved or conical portion of the nearest fitting should be at least 2.5D, except where this would not give an acceptable
value for the distance between the orifice plate and the downstream end of the 19-tube bundle flow straightener.
f It is not possible to find an acceptable location for a 19-tube bundle flow straightener (1998) downstream of the particular fitting for all values of L
f
to
which the column applies.
g If
=0.46 a value of 9.5 is possible.
h if
=0.54 a value of 13 is possible.
Table B-7. Permitted Range of Straight Lengths Between Orifice Plate and 19-Tube Bundle Flow Straightener
(1998) Downstream of Fittings Located at a Distance, L
f
, From the Orifice Plate
Diameter
Ratio,
Single 90° bend
b
Two 90° bends
b
in perpendicular planes
(2D

S)
a
Single 90° tee
30 > L
f

18 L
f

30 30 > L
f

18 L
f

30 30 > L
f

18 L
f

30
1 2 3 4 5 6 7
-- A
c
B
d
A
c
B
d
A
c
B
d
A
c
B
d
A
c
B
d
A
c
B
d

0.20 5 to 14.5 1 to n
e
5 to 25 1 to n
e
5 to 14.5 1 to n
e
5 to 25 1 to n
e
5 to 14.5 1 to n
e
1 to 25 1 to n
e
0.40 5 to 14.5 1 to n
e
5 to 25 1 to n
e
5 to 14.5 1 to n
e
5 to 25 1 to n
e
5 to 14.5 1 to n
e
1 to 25 1 to n
e
0.50 11.5 to
14.5
3 to n
e
11.5 to
25
3 to n
e
9.5 to
14.5
3 to n
e
9 to 25 1 to n
e
11 to 13 1 to n
e
9 to 23 1 to n
e
0.60 12 to 13 5 to n
e
12 to 25 5 to n
e
13.5 to
14.5
5 to n
e
9 to 25 1 to n
e fh
7 to n
e
11 to 16 1 to n
e
0.67 13 7 to n
e
13 to
16.5
7 to n
e
13 to
14.5
7 to n
e
10 to 16 5 to n
e f
8 to n
e
11 to 13 6 to n
e
0.75 14 8 to n
e
14 to
16.5
8 to n
e f
9.5 to n
e
12 to
12.5
8 to n
e f
9 to n
e
12 to 14 7 to n
e
Recom-
mended
13 for

0.67
13 for

0.75
14 to
16.5 for

0.75
14 to
16.5 for

0.75
13.5 to
14.5 for

0.67
13.5 to
14.5 for

0.75
12 to
12.5 for

0.75
12 to
12.5 for

0.75
13 for

0.54
13 for

0.75
12 to 13
for

0.75
12 to 13
for

0.75
Diameter
Ratio,
Any fitting
30 > L
f

18 L
f

30
1 8 9
-- A
c
B
d
A
c
B
d

0.20 5 to 11 1 to n
e
5 to 13 1 to n
e
0.40 5 to 11 1 to n
e
5 to 13 1 to n
e
0.50
fg
1 to n
e
11.5 to 14.5 3 to n
e
0.60
f
7 to n
e
12 to 16 6 to n
e
0.67
f
8 to 10 13 7 to n-1.5
e
0.75
f
9.5
f
8 to 22
Recom-
mended
9.5 for

0.54
9.5 for

0.75
13 for

0.67
13 for

0.75
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