CEMP-E
TI 810-11
30 November 1998
Qs (1 + 0.00131 ( T sh ) )
(eq. 2-8 SI)
Kv=
0.161 ( pe + po ) ∆ p
Where:
3
Kv = flow coefficient, m /hr @ ∆p = 100 kPa (1 bar)
Qs = steam flow, kg/hr
(1 + 0.00131 (Tsh)) = superheat factor.
Tsh = superheat temperature, degrees C
0.161 = compressibility and conversion factor.
pe = absolute pressure of the steam entering the valve, kPa
po = absolute pressure of the steam entering the coil, kPa
∆p = pressure drop through the valve, kPa
Q s (1 + 0.0007 ( T sh ) )
Cv =
(eq. 2-8 IP)
2.11 ( pe + po ) ∆ p
Where:
Cv = flow coefficient, gpm @ ∆p = 1 psid
Qs = steam flow, lb/hr
(1 + 0.0007 (Tsh)) = superheat factor.
Tsh = superheat temperature, degrees F
2.11 = compressibility and conversion factor.
pe = absolute pressure of the steam entering the valve, psia
po = absolute pressure of the steam entering the coil, psia
∆p = pressure drop through the valve, psid
Tsh is the superheat temperature of the steam reduced to the lower pressure from the higher pressure.
2-27
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