VALVOLE DI CONTROLLO E INTERCETTAZIONE, SISTEMI DI AZIONAMENTO,
DISCHI DI ROTTURA E DISPOSITIVI DI SICUREZZA UTILIZZATI
NELL’INDUSTRIA DI PROCESSO
Milano, 18 Aprile 2018
Auditorio TECNIMONT
Rising Stem Globe Control Valves vs Ball Control Valves.
A comparison in terms of mass,
fluid dynamic performance, fields of application.
Michele Ferrante
VSI Controls
When a Ball Valve can be used as a Control Valve?
Can it replace a Globe Valve?
A Ball Valve is typically a quarter-turn valve with a perforated ball in the
middle to control flow. These valves are known for being durable with
excellent shutoff, but do not always offer very precise control.
In recent years the use of Ball Valves for regulating service has increased,
moving also in the field of severe applications, where the use of multi-stage
trims is required.
For some control applications there is nowadays the possibility to install a
Ball Valve or a Globe Valve, and the choice of the best model for the
application is not always clear to
the EPCs or to the End Users.
Scope of this work is to highlight the main features of
Control Globe and Ball Valves, and to suggest
guidelines in choosing one or the other.
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Control Valves Working Principle
Process Control System (or Control Loop) usually consists of:
 a Sensor that measure a Process Variable
 a Transmitter
 a Controller that compares the Process Variable received from the Transmitter with the
Set Point.
 a final control element, composed by an actuated Control Valve, that receives the
Correcting Signal by the Controller
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Main Features
Globe Control
Valve
Ball Control
Valve
Linear motion of the closure member (Plug)
Rotary motion of the closure member (Ball)
In-line or angle body design
In-line design
Body and bonnet (flanged, welded or screwed)
Top Entry or Side Entry
Regulating (contoured) Plug or Cage trim
Trunnion or Floating trim
Unbalanced or P/B trim
Unbalanced trim
Manually or Power actuated
Manually or Power actuated
Pneumatic, Electric, Hydraulic actuators
Pneumatic, Electric, Hydraulic actuators
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Main Features
Globe Control Valve
Ball Control Valve
ND
0,5 to 36’’ (24’’ more reasonable limit)
2 to 60’’ (and more)
Pressure Class
Up to:
ANSI 4500 (775 bar/11240 PSI)
API 20000 (1380 bar/20000 PSI)
Up to:
ANSI 900 (150 bar/2175 PSI)
(up to ANSI 2500 for special applications)
Temperature Limits
From -196°C to 600°C and more
From -196°C to 250°C
(extreme applications up to 450°C on small
valves)
End connections
Fluid
Flanged, BW, SW
Gas, Liquid, Mixtures, Flashing, Slurry
Allowable Pressure drops
300 bar on gas and liquid
Up to 700 bar on choke applications
Up to 100 bar
Seat Leakage Class
(ANSI/FCI 70-2)
UP to:
Class V metal
Class VI soft
Bidirectional (depending on trim type)
UP to:
Class V metal
Class VI soft
Bidirectional
Reduced Port Option
Packing options
Available
Single, double, leak off, low emission…
The characteristics listed here are indicative and refer to the most common applications.
Special projects can exceed these limits
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Typical Trim Types
Globe Valves
Contoured Plug
Cage Trim
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Multicage and
Special Trim
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Typical Trim Types
Globe Valves
Unbalanced Trim
Pressure Balanced
trim
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Tipical Trim Types
Ball Valves
Full bore
Drilled Disk Trim
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Multicage and
Special Trim
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Mass Comparison: VSI Controls GLS Globe Valve vs HXL Ball
Valve
Mass Comparison Class 300 Flanged
3750
3500
3250
3000
2750
2500
2250
2000
1750
1500
1250
1000
750
500
250
0
HXL Ball Valve
GXL-GLS globe Valve
DN [inch]
2
3
4
6
8
10
12
14
16
18
20
Mass [kg]
3500
3250
3000
2750
2500
2250
2000
1750
1500
1250
1000
750
500
250
0
Mass [kg]
Mass Comparison Class 150 Flanged
Mass Comparison Class 600 Flanged
3200
GLS Globe Valve
2800
4
6
8
Mass [kg]
3600
HXL Ball Valve
3
10
12
14
16
18
20
24
Mass Comparison Class 900 Flanged
4000
Mass [kg]
5200
4800
4400
4000
3600
3200
2800
2400
2000
1600
1200
800
400
0
GXL-GLS Globe Valve
DN [inch]
2
24
HXL Ball Valve
HXL Ball Valve
GLS Globe Valve
2400
2000
1600
1200
DN [inch]
800
400
DN [inch]
0
2
3
4
6
8
10
12
14
16
18
20
24
2
3
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6
8
10
12
14
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Mass Comparison: VSI Controls GLS Globe Valve vs HXL Ball
Valve
Mass Comparison Class 300 Flanged
3750
3500
3250
3000
2750
2500
2250
2000
1750
1500
1250
1000
750
500
250
0
Mass [kg]
3500
3250
3000
2750
2500
2250
2000
1750
1500
1250
1000
750
500
250
0
Delta % on mass comparison
Ball/Globe:
-1%
DN [inch]
2
3
4
6
8
10
12
14
16
18
20
Mass [kg]
Mass Comparison Class 150 Flanged
Delta % on mass comparison
Ball/Globe:
-10%
DN [inch]
2
24
Mass Comparison Class 600 Flanged
3600
3200
2800
Delta % on mass comparison
Ball/Globe:
+8%
2400
4
6
8
10
12
14
16
18
20
24
Mass Comparison Class 900 Flanged
4000
Mass [kg]
5200
4800
4400
4000
3600
3200
2800
2400
2000
1600
1200
800
400
0
3
Delta % on mass comparison
Ball/Globe:
+9%
2000
1600
1200
DN [inch]
800
400
DN [inch]
0
2
3
4
6
8
10
12
14
16
18
20
24
2
3
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6
8
10
12
14
16
18
10
120000
110000
100000
Cv [gpm]
Cv max Valve Class 600 full bore
Cv Comparison:
VSI Controls GLS Globe
Valve
vs HXL Ball Valve
HXL Ball Valve
GXL-GLS globe Valve
90000
80000
70000
60000
50000
40000
30000
 HXL full bore.
20000
10000
 GLS full port, contoured plug.
DN [inch]
2
3
4
6
8 10 12 14 16 18 20 24 28 30 32 36 40 48
Cv max Valve Class 600 full bore
16500
15000
13500
Cv [gpm]
0
HXL Ball Valve
GXL-GLS globe Valve
12000
10500
9000
7500
6000
4500
3000
1500
DN [inch]
0
2
3
4
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8
10
12
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Capacity vs Mass Comparison:
VSI Controls GLS Globe Valve vs HXL Ball Valve
Capacity vs Mass Comparison Class 600
 HXL full bore.
4,5
gpm/kg
5,0
 GLS full port, contoured
HXL Ball Valve
plug.
GLS Globe Valve
4,0
3,5
3,0
Delta %
2,5
2,0
Ball/Globe:
1,5
+218%
1,0
0,5
DN [inch]
0,0
2
3
4
6
8
10
12
14
16
18
20
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12
Capacity vs Mass Comparison:
VSI Controls GLS Globe Valve vs HXL Ball Valve
Cv [gpm]
Capacity vs Mass Comparison
16500
16500
 HXL full bore.
15000
15000
 GLS full port, contoured
13500
13500
12000
12000
10500
10500
9000
9000
7500
7500
6000
6000
4500
4500
3000
3000
1500
1500
0
plug.
Delta %
Ball/Globe:
+218%
0
64
108
170
272
439
720
1063
1425
2185
2580
2990
4677
Mass [kg]
HXL ball Valve
GLS Globe Valve
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Characteristic Curve Comparison :
VSI Controls GLS Globe Valve vs HXL Ball Valve
Cv %
Characteristic Curve
100
90
80
 HXL full bore.
HXL Full bore Ball Valve
 GLS full port, contoured
70
GLS Globe Valve (Equi%)
plug, equi% char.
60
50
40
30
20
10
Travel %
0
0
10
20
30
40
50
60
70
80
90
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100
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Cv max
Cv Comparison:
VSI Controls
GLS Globe Valve
vs HXL Ball Valve
25600
15900
Cv vave & Cv body
[gpm]
12800
6400
3200
1570
1600
1054
800
400
200
Cv valve - ball DN10'' - full port
 HXL full bore.
Cv body - globe DN10"
 GLS full port, contoured plug
Cv body + seat - globe DN10'' - full port
100
Cv body - ball DN10'''
Cv valve - globe DN10'' - full port
50
50
100
200
400
800
1600
3200
6400
Cv trim
[gpm]
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Rangeability comparison:
VSI Controls GLS Globe Valve
vs HXL Ball Valve
Cv %
100
90
80
70
60
50
40
30
20
10
0
Travel %
0
10
20
30
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40
50
60
70
80
90
100
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Rangeability comparison: VSI Controls GLS Globe Valve
vs HXL Ball Valve
Cv %
100
90
80
70
60
50
40
30
20
10
0
Travel %
0
10
20
30
40
50
60
70
80
90
100
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Fluid Dynamic Comparison:
Cage trim Globe Valve vs Drilled Disk Ball
FL Coefficient
FL %
FL Values
102%
100%
98%
96%
94%
92%
90%
88%
86%
HXL Drilled Disk FL coeff.
84%
Cage Globe Valve FL coeff.
82%
Travel %
80%
0%
10%
Curves related to:
20%
30%
40%
50%
60%
70%
80%
90%
100%
 single cage globe valve trim
 single drilled disk on full bore for ball valve
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Fluid Dynamic Comparison:
Cage trim Globe Valve vs Drilled Disk Ball
Xt Coefficient
Xt %
Xt Values
100%
95%
Xt=
Δ𝑃
𝑃1 𝑙𝑖𝑚𝑖𝑡
90%
85%
80%
75%
70%
65%
HXL Drilled Disk Xt coeff.
60%
Cage Globe Valve FL coeff.
55%
Travel %
50%
0%
10%
Curves related to:
20%
30%
40%
50%
60%
70%
80%
90%
100%
 single cage globe valve trim
 single drilled disk on full bore for ball valve
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FL %
Fluid Dynamic Comparison:
Multicage trim Globe Valve
vs Multicage Ball Valve FL Coefficient
FL Values
100%
96%
92%
88%
84%
80%
76%
72%
HXL Multicage FL coeff.
68%
Double Cage Globe Valve FL coeff.
64%
Travel %
60%
0%
10%
Curves related to:
20%
30%
40%
50%
60%
70%
80%
90%
100%
 double cage globe valve trim
 multicage 3 stages ball valve trim
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Fluid Dynamic Comparison:
Double Cage trim Globe Valve
vs Multicage Ball Valve Xt Coefficient
Xt=
Xt %
Δ𝑃
𝑃1 𝑙𝑖𝑚𝑖𝑡
Xt Values
118%
114%
110%
106%
102%
98%
94%
90%
86%
82%
78%
74%
70%
66%
62%
58%
54%
50%
46%
42%
38%
34%
30%
HXL Multicage Xt coeff.
Double Cage Globe Valve FL coeff.
0%
10%
20%
Curves related to:
30%
40%
Travel %
50%
60%
70%
80%
90%
100%
 double cage globe valve trim
 multicage 3 stages ball valve trim
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Conclusions
 Both Globe Valves and Ball Valves are used for Control applications. Both
could be equipped with several kind of trims, to fit with several industrial
applications.
 Some geometrical features make the Ball Valve less suitable when an
accurate control is required: over a certain opening, especially on full bore
trims, a large amount of flow rate change with a minimum variation in
opening degrees. There is also some ‘play’ between the stem and ball
that hinders precise control. Lastly, the amount of torque required to
adjust Ball Valves do not allow for fine adjustment near the “closed” and
“open” position.
 The use of trunnion mounted ball design, as well as precise coupling
between ball and stem, and the possibility to equip Control Ball Valves
with disk or cage trim partially limit this disadvantages.
 When a precise control at any flow rate is mandatory, the Globe Valve still
have a significant margin of advantage.
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Conclusions
 The possibility to install P/B trims in Globe Valves, for high size valves and/or with high pressure drop,
allows the reduction of actuating thrusts. This possibility is not available for Control Ball valves, which are
therefore often equipped with large size actuators.
 An additional advantage of Globe Valves is related to the possibility of being used for high temperature
applications, where the complex tolerance chain and the criticality of differential thermal expansion limit
the use of a Ball Valve.
 The high and reliable sealing performance of the Ball Valve place it in advantage when the shutoff class
is the fundamental requirement.
 Comparing the Control Globe Valve with the Control Ball Valve
from the point of view of valve weight for same ND/Class a
clear advantage of one over the other can not be identified.
 A comparison in terms of Capacity shows instead a huge
advantage for the Ball Valves. This advantage is evident both
in terms of capacity for a given ND and Class, than in terms of
net capacity for mass unit.
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Conclusions
 From the point of view of the Characteristic Curve the Ball Control Valve is not affected in any way to
valve body Cv, and the resulting curve is determined solely by the trim Cv.
 The possibility to regulate small clearance flow rate at first openings, combined with the possibility to
discharge huge flow rates at valve completely open allows the Control Ball Valve to reach rangeability
values theoretically infinite.
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Conclusions
 Fluyd Dynamics coefficents are higher for Control Globe Valves, both regarding anti cavitation
performances on liquid flows, and regarding velocity control and noise reduction on gas flows. The
advantage of Globe Valves is significant both in case of full bore valves, and in case of application of
cage or multicage trims.
 Control Ball Valve can reach FL and Xt values comparable to those of a Globe Valves only in
correspondence of some range of openings, while the globe valve assure a more constant value of
coefficient over the entire stroke of the valve.
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Thanks for Your Attention
M.Ferrante
michele.ferrante@vsicontrols.com
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