• Cavitation Decreased—A properly sized Design CAV4 valve with Cavitrol IV trim decreases cavitation and its resultant damage and noise.
• Long Trim Life—Patented pressure-staging design and separation of shutoff and throttling locations decrease clearance-flow erosion. Hardened trim materials result in improved wear resistance.
• Tight Shutoff—Soft metal-to-metal seat provides tight shutoff without the need for periodic lapping. The anti-extrusion ring provides an enhanced valve plug seal.
• TSO (Tight Shutoff) Trim—Valves with TSO trim (figure 2) are factory tested to a more stringent Emerson Process ManagementTM test requirement of no leakage at time of shipment using ANSI/FCI Class V procedures.
• Efficient Operation—Expanding flow area design takes advantage of the ability of the liquid to undergo a greater pressure drop in initial stages without cavitating. This results in a much lower inlet pressure to the final stage.
• Characterization—Special characterized cages are available to provide customer specified rangeability for specific system requirements.
• Easy Maintenance—Design reduces maintenance downtime by permitting quick disassembly with easy access to valve trim and valve plug seat. Separable seat ring for low temperature applications (at or below 232°C [450°F]) makes maintenance easier.

Note
Neither Emerson, Emerson Process Management, nor any of their affiliated entities assumes responsibility for the selection, use and maintenance of any product. Responsibility for the selection, use, and maintenance of any product remains with the purchaser and end-user.

where,
∆PFlow = differential between flowing inlet and
flowing outlet pressure, bar, absolute
(psia)
    P1 = inlet pressure, bar, absolute (psia)
    Pv = vapor pressure of process liquid at
inlet temperature, bar, absolute (psia)

1. If the application ratio is less than 1.0 and the maximum pressure drop is between 206 bar [3000 psi] and 414 bar [6000 psi] for linear trim (or between 206 bar [3000 psi] and 310 bar [4500 psi] for approximate linear trim), service is potentially cavitating and a Design CAV4 valve with Cavitrol IV trim should be selected.
2. If the application ratio is equal to or greater than 1.0 and the maximum pressure drop is less than or equal to 206 bar (3000 psi), service is flashing and the Design CAV4 body with Cavitrol IV trim should be selected.
3. If the application ratio is less than 1.0 and the maximum pressure drop is less than 206 bar (3000 psi), then refer to other anticavitation products. Refer to table 1 and figure 6 for trim material selection.

Application Information

1. Process liquid—State particle size and type of entrained impurities, if any
2. Specific gravity of liquid
3. Temperature and vapor pressure of liquid
4. Critical pressure
5. Range of flowing inlet pressures
6. Maximum outlet pressure
7. Pressure drops

Valve Information

To determine what information is needed for ordering the valve and trim, refer to the specifications. Review the description at the right of each specification or in the referenced tables, figures, and bulletins, and indicate the desired choice wherever there is a selection to be made.

Actuator and Accessory Information

Select the specific actuator and accessories from the appropriate bulletins. Piston or diaphragm actuators may be used. Specify any additional ordering information as required from actuator or accessory bulletins.

Available Configurations and Valve Body Sizes

Common Characteristics: Design CAV4 angle, globe, or offset globe valve with four-stage Cavitrol IV trim including soft metal-to-metal seat. Valve plug action is push-down-to-close
Seal Ring Construction: ■NPS 2, ■3, ■4, or ■6 valve body with pressure-balanced valve plug and spring-loaded PTFE seal ring. For use in low-temperature applications
Stem-Balanced Construction: ■NPS 2 or ■4 valve body with stem-balanced valve plug (valve stem diameter—for that portion of stem that passes through bonnet—is equal to nominal port diameter). For use in high-temperature applications
Piston Ring Construction: NPS 6 valve body with pressure-balanced valve plug and five graphite piston rings. For use in high-temperature applications

End Connection Style(1)

Buttwelding Ends: All buttwelding end schedules per ASME B16.25 that are compatible with ASME B16.34 valve body rating
Raised-Face or Ring-Type Joint Flanged Ends: Inlet connection is CL2500 flange per B16.5. Outlet connection mates with CL2500 flange and has tapped bolt holes with line flange studs

Maximum Inlet Pressure and Temperatures(1)(2)

Consistent with applicable CL2500 pressure temperature ratings per ASME B16.34 unless limited by individual pressure drop limits shown in figure 6 or temperature limits in table 1

Maximum Pressure Drop(2)

See figure 6

Material Temperature Capabilities(2)

Seal Ring Construction: 18 to 232°C (0 to 450°F)
Stem-Balanced and Piston Ring Constructions: Up to 427°C (800°F) unless limited by selection of other parts (table 1)

Shutoff Classification

TSO (Tight Shutoff) Trim: Valves with TSO trim are factory tested to a more stringent Emerson Process Management test requirement of no leakage at time of shipment using ANSI/FCI 70-2 and IEC 60534-4 Class V procedures.
Piston Ring Construction: Class IV per
ANSI/FCI 70-2 and IEC 60534-4
All Others: Class VI per ANSI/FCI 70-2 and
IEC 60534-4

Flow Direction

In through the side connection and out the bottom connection

Noise Levels

Because of cavitation elimination, noise is typically not a problem with Cavitrol IV trim. For virtually all applications, noise levels will be below 90 dBA. If more stringent noise specifications must be met, contact your Emerson Process Management sales office

Construction Materials

See table 1

Flow Characteristic

Linear

Maximum Flow Coefficients (CV)

Linear: ■NPS 2 valve, 8.25; ■NPS 3 valve, 14.6; ■NPS 4 valve, 21.9: ■NPS 6 valve, 55.6
Characterized: ■NPS 2 valve, 11.3; ■NPS 3 valve, 24; ■NPS 4 valve, 38.2; ■NPS 6 valve, 89.1. Also see the section titled Coefficients in this bulletin or Catalog 12

Valve Recovery and Cavitation Coefficients

Recovery Coefficient Linear: Km = 0.99. Characterized: Km = 0.98. This value defines the maximum allowable pressure drop that is effective in producing flow as shown in the following equation:
∆Pallowable = Km (P1 (flowing)-rcPv)
Cavitation Coefficient Linear and Characterized: Kc = 1.0. This value predicts the beginning of cavitation-related damage as shown in the following equation:
∆PCavitation = Kc (P1 (flowing)Pv)
where,
∆Pallowable = maximum allowable pressure drop that is effective in producing flow, bar (psi)
P1 (flowing) = flowing inlet pressure, bar, absolute (psia)
rc = critical pressure ratio from Catalog 12
Pv = vapor pressure of liquid at inlet temperature, bar, absolute (psia)

Port Diameters and Unbalance Area

See table 2

Minimum Seat Load Force

First refer to figure 7 to determine minimum seat load per inch of port circumference; then multiply that value by the port circumference from table 2

Valve Plug Travel

See table 2

Yoke Boss and Valve Stem Diameters

See table 2

Approximate Weight

See table 2

Options

■Flushing trim, two plates used in place of Cavitrol IV trim, to protect valve body surfaces and Cavitrol IV trim from damage during pipeline flushing: ■characterized cage; and ■driver for installation and removal of cage retainer ■ENVIRO-SEAL® packing is available

Note
Neither Emerson, Emerson Process Management, nor any of their affiliated entities assumes responsibility for the selection, use and maintenance of any product. Responsibility for the selection, use, and maintenance of any product remains with the purchaser and end-user.