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2
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EPDT-197
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3. Nominal size selection method
●
Nominal size selection chart
●
Formula for calculating the required nominal size
The steam volume “W” required to raise the temperature of “Q” amount of water by
“B” degrees Celsius in “A” amount of time is calculated as follows:
W: Steam volume (kg/h)
B: Desired temperature rise (
℃
)
Q: Water volume (kg)
A: Desired time(h)
Based on the steam volume (W kg/h) and steam pressure (P MPa) values obtained
by the above formula, the appropriate nominal size is selected using the “Nominal
size selection chart”.
●
Nominal size calculation example (MS-2)
When the temperature of 7000kg of water is to be raised from 20 to 60
℃
over a
period of 1 hour, with a steam pressure of 0.5MPa,the nominal size is calculated as
follows:
=560(kg/h)
Referring to the “Nominal size selection chart”, find the point where the 0.5MPa and
the 560 (flow rate) lines intersect. As the point is between the 40A and 50A sizes, the
larger size of 50A is selected.
[MS-1, MS-3-13]
[MS-2, MS-4-13]
A
Q
B
w
×
×
=
500
1
500
7000
)
20
60
(
×
×
−
=
w
