Rising Stem Globe Control Valves vs Ball Control Valves. A comparison in terms of mass, fluid dynamic performance, fields of application.

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Auditorio TECNIMONT Rising Stem Globe Control Valves vs Ball Control Valves.

1 VALVOLE DI CONTROLLO E INTERCETTAZIONE, SISTEMI DI AZIONAMENTO, DISCHI DI ROTTURA E DISPOSITIVI DI SICUREZZA UTILIZZATI NELL INDUSTRIA DI PROCESSO Milano, 18 Aprile 218 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.

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.

2 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. Copyright VSI Controls all rights reserved 217 2

3 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 Copyright VSI Controls all rights reserved 217 3

Pneumatic, Electric, Hydraulic actuators Rotary motion of the closure member (Ball) In-line design Top Entry or Side Entry Trunnion or

4 Main Features Globe Control Valve Ball Control Valve Linear motion of the closure member (Plug) In-line or angle body design Body and bonnet (flanged, welded or screwed) Regulating (contoured) Plug or Cage trim Unbalanced or P/B trim Manually or Power actuated Pneumatic, Electric, Hydraulic actuators Rotary motion of the closure member (Ball) In-line design Top Entry or Side Entry Trunnion or Floating trim Unbalanced trim Manually or Power actuated Pneumatic, Electric, Hydraulic actuators Copyright VSI Controls all rights reserved 217 4

5 Main Features Globe Control Valve Ball Control Valve ND,5 to 36 (24 more reasonable limit) 2 to 6 (and more) Pressure Class Up to: ANSI 45 (775 bar/1124 PSI) API 2 (138 bar/2 PSI) Up to: ANSI 9 (15 bar/2175 PSI) (up to ANSI 25 for special applications) Temperature Limits From -196 C to 6 C and more From -196 C to 25 C (extreme applications up to 45 C on small valves) End connections Fluid Allowable Pressure drops Seat Leakage Class (ANSI/FCI 7-2) Reduced Port Option Packing options 3 bar on gas and liquid Up to 7 bar on choke applications UP to: Class V metal Class VI soft Bidirectional (depending on trim type) Flanged, BW, SW Gas, Liquid, Mixtures, Flashing, Slurry Available Up to 1 bar UP to: Class V metal Class VI soft Bidirectional 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 Copyright VSI Controls all rights reserved 217 5

Typical Trim Types Globe Valves Contoured Plug Cage Trim

9 Mass Comparison: VSI Controls GLS Globe Valve vs HXL Ball Valve Mass [kg] Mass Comparison Class 15 Flanged HXL Ball Valve GXL-GLS globe Valve DN [inch] Mass [kg] Mass Comparison Class 3 Flanged HXL Ball Valve GXL-GLS Globe Valve DN [inch] Mass[kg] Mass Comparison Class 6 Flanged HXL Ball Valve 36 GLS Globe Valve DN [inch] 4 DN [inch] Copyright VSI Controls all rights reserved Mass [kg] Mass Comparison Class 9 Flanged HXL Ball Valve GLS Globe Valve 9

10 Mass Comparison: VSI Controls GLS Globe Valve vs HXL Ball Valve Mass [kg] Mass Comparison Class 15 Flanged Delta % on mass comparison Ball/Globe: -1% DN [inch] Mass [kg] Mass Comparison Class 3 Flanged Delta % on mass comparison Ball/Globe: -1% DN [inch] Mass[kg] Mass Comparison Class 6 Flanged Delta % on mass comparison Ball/Globe: +8% Mass Comparison Class 9 Flanged Delta % on mass comparison Ball/Globe: +9% 8 DN [inch] 4 DN [inch] Copyright VSI Controls all rights reserved 217 1

12 11 1 9 8 7 6 5 4 3 2 1 Cv[gpm] Cv max Valve Class 6 full bore HXL Ball Valve GXL-GLS globe Valve DN [inch] 2 3 4 6 8 1 12 14 16 18 2 24 28 3 32 36 4 48 Cv Comparison: VSI Controls GLS Globe Valve

11 Cv[gpm] Cv max Valve Class 6 full bore HXL Ball Valve GXL-GLS globe Valve DN [inch] Cv Comparison: VSI Controls GLS Globe Valve vs HXL Ball Valve HXL full bore. GLS full port, contoured plug Cv [gpm] Cv max Valve Class 6 full bore HXL Ball Valve GXL-GLS globe Valve DN [inch] Copyright VSI Controls all rights reserved

12 Capacity vs Mass Comparison: VSI Controls GLS Globe Valve vs HXL Ball Valve 5, 4,5 4, gpm/kg Capacity vs Mass Comparison Class 6 HXL Ball Valve GLS Globe Valve HXL full bore. GLS full port, contoured plug. 3,5 3, 2,5 Delta % 2, 1,5 Ball/Globe: 1, +218%,5, DN [inch] Copyright VSI Controls all rights reserved

13 Capacity vs Mass Comparison: VSI Controls GLS Globe Valve vs HXL Ball Valve Capacity vs Mass Comparison HXL full bore. GLS full port, contoured plug Cv [gpm] Delta % Ball/Globe: % Mass [kg] HXL ball Valve GLS Globe Valve Copyright VSI Controls all rights reserved

Characteristic Curve Comparison : VSI Controls GLS Globe Valve vs HXL Ball Valve 1 Cv % Characteristic Curve 9 8 7 6 HXL Full bore Ball Valve GLS Globe

14 Characteristic Curve Comparison : VSI Controls GLS Globe Valve vs HXL Ball Valve 1 Cv % Characteristic Curve HXL Full bore Ball Valve GLS Globe Valve (Equi%) HXL full bore. GLS full port, contoured plug, equi% char Travel % Copyright VSI Controls all rights reserved

15 Cv max Cv Comparison: VSI Controls Cv vave & Cv body [gpm] GLS Globe Valve vs HXL Ball Valve Cv valve - ball DN1'' - full port Cv body - globe DN1" Cv body + seat - globe DN1'' - full port Cv body - ball DN1''' HXL full bore. GLS full port, contoured plug Cv valve - globe DN1'' - full port Cv trim [gpm] Copyright VSI Controls all rights reserved

18 Fluid Dynamic Comparison: Cage trim Globe Valve vs Drilled Disk Ball F L Coefficient 12% 1% 98% 96% 94% 92% 9% 88% F L % F L Values 86% 84% 82% HXL Drilled Disk FL coeff. Cage Globe Valve FL coeff. Travel % 8% % 1% 2% 3% 4% 5% 6% 7% 8% 9% 1% Curves related to: single cage globe valve trim single drilled disk on full bore for ball valve Copyright VSI Controls all rights reserved

Fluid Dynamic Comparison: Cage trim Globe Valve vs Drilled Disk Ball Xt Coefficient 1% 95% Xt % Xt Values Xt= 9% 85% 8% 75% 7% 65% 6% 55% HXL Drilled Disk Xt coeff. Cage Globe Valve FL coeff.

19 Fluid Dynamic Comparison: Cage trim Globe Valve vs Drilled Disk Ball Xt Coefficient 1% 95% Xt % Xt Values Xt= 9% 85% 8% 75% 7% 65% 6% 55% HXL Drilled Disk Xt coeff. Cage Globe Valve FL coeff. Travel % 5% % 1% 2% 3% 4% 5% 6% 7% 8% 9% 1% Curves related to: single cage globe valve trim single drilled disk on full bore for ball valve Copyright VSI Controls all rights reserved

Fluid Dynamic Comparison: Multicage trim Globe Valve vs Multicage Ball Valve F L Coefficient F L % F L Values 1% 96% 92% 88% 84% 8% 76% 72% 68% HXL Multicage FL coeff.

20 Fluid Dynamic Comparison: Multicage trim Globe Valve vs Multicage Ball Valve F L Coefficient F L % F L Values 1% 96% 92% 88% 84% 8% 76% 72% 68% HXL Multicage FL coeff. 64% Double Cage Globe Valve FL coeff. Travel % 6% % 1% 2% 3% 4% 5% 6% 7% 8% 9% 1% Curves related to: double cage globe valve trim multicage 3 stages ball valve trim Copyright VSI Controls all rights reserved 217 2

21 Fluid Dynamic Comparison: Double Cage trim Globe Valve vs Multicage Ball Valve Xt Coefficient X t Values Xt= 118% 114% 11% 16% 12% 98% 94% 9% 86% 82% 78% 74% 7% 66% 62% 58% 54% 5% 46% 42% 38% 34% 3% Xt % HXL Multicage Xt coeff. Double Cage Globe Valve FL coeff. Travel % % 1% 2% 3% 4% 5% 6% 7% 8% 9% 1% Curves related to: double cage globe valve trim multicage 3 stages ball valve trim Copyright VSI Controls all rights reserved

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.

minimum variation in opening degrees. There is also some play between the stem and ball that hinders precise control.

22 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. Copyright VSI Controls all rights reserved

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.

23 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. Copyright VSI Controls all rights reserved

The possibility to regulate small clearance flow rate at first openings, combined with the possibility to discharge huge

24 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. Copyright VSI Controls all rights reserved

Conclusions Fluyd Dynamics coefficents are higher for Control Globe Valves, both regarding anti cavitation performances on liquid flows, and regarding

The advantage of Globe Valves is significant both in case of full bore valves, and in case of application of cage or multicage trims.

25 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 F L 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. Copyright VSI Controls all rights reserved

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