CONTROL VALVE
Calculation note
CONTROL VALVE USER GUIDE Controlvalve Version Creation date Correspondant Last revision
Regulation valve sizing
This calculation sheet is the property of the …... and shall not be disclosed to others or reproduced in any manner without its permission. Databook has to be read and assimilated before using the worksheet. It is advised to make the first calculation by hand in order to have a better comprehension of the method applied. 1 REFERENCE This note is in accordance with the international standard for sizing control valves All formulas are available in the sheet " Formulas_comparison". Formulas enclosed in blue are used in the sheet "design" 2 ASSUMPTIONS Calculation consider valves without adjacent fittings They are made for turbulent flowrates 3 DOMAIN OF VALIDITY NA 4 FORMULAS 4.1.Symbols Cv = valve sizing coefficient q = Volumetric flowrate(m3/h) W = Mass flowrate (kg/h) P1 = Upstream absolute static pressure P2 = downstream absolute static pressure Pv = Absolute vapor pressure of liquid at inlet temperature. Pc = Absolute thermodynamic critical pressure Cf = Factor of critical flow given by the constructor ( is equivalent to the FL coefficient: pressure recovery factor) Gf = liquid specific gravity (ratio of density of liquid on density of water) xT = rated pressure drop ratio factor T1= Absolute upstream temperature °K Z = Compressibility factor M = gas molecular weight FF = factor resulting from the liquid critical pressure Fγ= factor corresponding to the specific heat ratio γf = mass fraction of the liquid phase γg= mass fraction of the vapor phase d1=Downstream density of blend, kg/m3 d2=Downstream density of blend, kg/m3 W1l=upstream liquid flow, kg/h W2l=downstream liquid flow, kg/h W1v=upstream vapor flow, kg/h W2v=downstream vapor flow, kg/h d1l=upstream liquid density, kg/m3 d2l=Downstream liquid density, kg/m3 d1v=upstream vapor density, kg/m3 d2v=Downstream vapor density, kg/m3 5 OBJECTIVE This worksheet permits to calculate : - The Cv of the valve for liquid, vapor or two phase flows. Cv is the sizing coefficient used to characterize the flow capacity of valves. It corresponds to the number of US gallons flowing though the valve in one minute when the valve differential pressure is 1 PSI. - The flowrate circulating across the valve for a given Cv will be calculated with a manual approach of the specific flowrate. 6 INPUT Input have to be filled into yellow boxes xT and Cf coefficients depend on the kind of valve. Their values for the main types of valves are recorded in the sheet "table". Default values are atribuate to coefficients gamma, xT and Cf if the corresponding cells are kept empty (Cf cells comments) Curves describing the Cv % evolution in function of the shutting valve is available in the guard "opening" This evolution can be simulated with parabolic (P), linear (L), equal % (%) ou quick opening (QO) curves 7 RESULTS Results are displayed into blue boxes and these cells are protected.
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57355303.xls
CONTROL VALVE
Calculation note
CONTROL VALVE FORMULAS DATABOOK FORMULATIONS
non critical flow
Liquid Service
C V=
ΔPC f ²* ΔP s
CV=
critical flow
ΔP≥C f ²* ΔP s non critical
Compressible fluids
w 2 7.3∗C f ∗F P∗F R∗ Δ P ∗s γ 1
WITH
1 P 1 − P 2 ∗C f ²* P 1 2
q ∗ G∗T ∗Z 257∗C f ∗P 1
C V=
CV=
C V=
51.8∗W ΔP∗ d1d2
x= Y =1−
x≥F ∗γ x T
ΔP P1
Fγ=
Fγ =
x 3∗F γ∗x T
W T1∗Z ∗ 94.8∗F P∗P 1∗0.667 F γ∗x T ∗M
CV=
Pv ∗P v Pc
xF γ∗x T
W T1∗Z ∗ 94. 8∗F P∗P1∗Y x∗M Engorged
∆P est limité à 0.5 * Cf ² *P1 Avec vaporisation de liquide
ΔP s = P 1 − 0 . 96 −0 . 28∗ non engorged
1 P 1− P 2≥ ∗C f ²* P 1 2
critical
FISCHER FORMULATION (ANSI/ ISA/IEC)
w 27.3∗F P∗F R∗ Δ P∗γ1
q G∗T∗Z CV= ∗ 2 9 5 P 1−P 2 P 1P 2
CV=
MASONEILAN FORMULATIONS
W ff fg ∗ 2 7.3 Δ p f ∗γ f Δ P g∗γ g∗Y ²
Y =1−
WITH
γ 1.4
is limited to 0.667
γ 1.4
x 3∗F γ∗x T
Y=1−
Δ PG 3∗F ∗γ x T∗P 1
Avec
Two phase flow
W ∗103 d1= W 1l W 1v d1l d1v
d 2=
W ∗1 03 W 2l W 2v d2l d2v
Δ P f =P1−P 2
limited to
Δ Pg =P 1−P 2
limited to
Δ P f =C f ²* P 1−F F∗P v ΔP g =F γ∗x T ∗P 1
∆P est limité à 0.5 * Cf ² *P1 Sans vaporisation de liquide
CV=
36. 6∗W ΔP∗d1
NOTE 1) In the calculation sheet:
2) 3) 4)
5)
It is considered a valve installed without adjacent fitting and so FP =1 It is considered a turbulent flow and so FR =1 If it is considered fitting attached to the valve, xT should be replaced by xTP which combine xT and piping geometry factor Fitting attached to valve can have a significant impact for high recovery valves ( example: rotary valves like butterfly or ball valves) which have a rather low pressure drop coefficient at full opening. Manufactrers often provide FP values for swages installed adjacent to such rotary valves. Fr= facteur du nombre de Reynolds Si Rev<56; Fr=0.019 (Rev)^0.67 Si Rev>40000; Fr=1 Si 56
Property of TECHNIP. Reproduction, Copying, Distribution to Others not Authorized
57355303.xls
CONTROL VALVES
calculation note
CONTROL VALVE
LIQUID
VAPOUR
FLOW
PRESSURE
Activity-unit: N° Date Revision Issued by Checked by Item Service Case
old
old
old
old
old
old
DESIGN
DESIGN
DESIGN
DESIGN
DESIGN
DESIGN
0.0
0.0
0.0
0.0
0.0
0.0
cP
#VALUE!
#VALUE!
#VALUE!
#VALUE!
#VALUE!
#VALUE!
kg/m3 kg/m3 kg/m3 cP bar a bar a kg/m3
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
Inlet Pressure
bar (g)
Pressure Drop
bar
Outlet pressure
bar (g)
Temperature Vap. FlowRate
°C kg/hr
Liq. FlowRate Total FlowRate
kg/hr kg/hr
Over margin Flow Rate Vapour Fraction Molecular Weigth Viscosity Compressibility Cp/Cv (= gamma) Density @(0 ATM,15.66°C) Density @ cond. Density Viscosity Critical Pressure Vapour Pressure Fluid (liq +vap) Density
% kg/hr (weigth)
VALVE
XT (coefficient of rate from the diferential pressure of a regulation valve with no adjacent link , at engorged flow): Cf Table
Cf
(Cf table)
Flow regime Calculated Cv (If two phase flow : Cv= Cv gas + Cv liq )
Opening Law (QO / % / L / P ) Openning
OPENING
Margin @ 80% opening Quick Opening Equal Percentage
MAX FLOW @ 80% OPENING
FLOW CHARACTERISTIC
Installed Cv
Quick Opening Equal Percentage
% % (g)
Linear Parabolic
Linear Parabolic In the case of 2 phase flow with incondensable liquid and incondensable gas or with a liquid mixing to its own vapor, Cv value is calculated hereafter: Cv NOTES:
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file : 57355303.xls
CONTROL VALVE
Calculation note
CONTROL VALVE 100
90
80
70
% opening
60
50
40
30
20
10
0 0
10
20
30
40
50
60
70
80
90
100
% Cv
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57355303.xls
CONTROL VALVE
Calculation note
CONTROL VALVE Opening law definition in function of the % Cv %Cv 0 5 10 20 30 40 50 60 70 80 90 95 100
Q op 0 3.2 5.9 11 16 21.5 27 32 38 47 61.5 79.5 100
% Cv @ 80% opening 79.999 80
%Opening Eq % MP 0 21.5 15 37 24.5 55.5 39 67 47.5 47.5 75.3 55 81 63 86 70 90.5 77.5 85 92 100
100
80
L 0 5 10 20 30 40 50 60 70 80 90 95 100
Linearization Q op Eq % P 0.0 0.0 0.0 3.1 20.1 14.4 5.9 38.6 25.1 11.0 57.1 38.8 16.0 67.9 47.9 21.4 75.6 55.3 26.9 81.5 62.8 32.3 86.4 70.2 38.0 90.5 77.7 46.3 94.0 85.1 63.1 97.2 92.6 78.1 98.6 96.3 100.4 100.0 100.0 Q op 95.5
Eq % 47.25
P 73.12
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CONTROL VALVE
Calculation note
CONTROL VALVE
Typical values of valve coefficient Valve type
Trim Type 3 V-port plug 4 V-port plug 6 V-port plug Contoured plug
Globe, single port
60 diameter hole drilled cage 120 equal diameter hole drilled cage Characterized cage, 4 port Ported Plug Contoured plug
Globe, double port
Contoured plug Globe, angle
Characterized cage, 4 port Venturi V-notch Flat seat Tapered needle
Globe, small flow trim
Eccentric spherical plug Rotary Eccentric conical plug
Butterfly (centered shaft) High performance butterfly (eccentric shaft) Ball
Swing-through (70 °) Swing-through (60 °) Fluted vane (70 °) Offset seat (70 °) Full bore (70 °) Segmented ball
Flow direction Open or Close Open or Close Open or Close Open Close Outward or Inward Outward or Inward Outward Inward Inlet between seats Either direction Open Close Outward Inward Close Open Close Open Open Close Open Close Either Either Either Either Either Either
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CF or FL 0.9 0.9 0.9 0.9 0.8 0.9 0.9 0.9 0.85 0.9 0.85 0.9 0.8 0.9 0.85 0.5 0.98 0.85 0.95 0.85 0.68 0.77 0.79 0.62 0.7 0.67 0.67 0.74 0.6
XT 0.7 0.7 0.7 0.72 0.55 0.68 0.68 0.75 0.7 0.75 0.7 0.72 0.65 0.65 0.6 0.2 0.84 0.7 0.84 0.6 0.4 0.54 0.55 0.35 0.42 0.38 0.35 0.42 0.3
Fd 0.48 0.41 0.3 0.46 1 0.13 0.09 0.41 0.41 0.28 0.32 0.46 1 0.41 0.41 1 0.7 0.3 0.42 0.42 0.44 0.44 0.57 0.5 0.3 0.57 0.99 0.98
57355303.xls
WORKSHEET HISTORICS Version Number
Creation date
Author
Evolution details
V1.0
4/2/1999
G.Viguié
V1.0
3/10/2004
L. Van de Velde Control valve -Modification of the esthetic shape -Formulas updating -New table making the comparison between the formulas from the databook, fisher and Masoneilan constructors.
V1.1
9/7/2004
L. Van de Velde Control valve -Correction of the flow regime calculation
V1.2
11/11/2004
V1.21
9/21/2005
V1.22
12/15/2005
Control_valve_r0
L. Van de Velde Control valve - User guide development - Updating of the sheets "Table" and "Formulas_comparison" "Controlvalve_V1.2" has been validated by Daniel Martinière on march 2005 L. Van de Velde Control valve - Form revision in order to be in accordance with TECHNIP Standard L. Van de Velde Control valve - Correction of a bug concerning the Y calculation in case of compressible fluids for a non engorged case.
