3-pc Forged Steel Floating Soft Seated Ball Valve

A 3-piece forged steel floating soft seated ball valve is a quarter-turn isolation valve whose body is machined from a solid forging and built as two end caps plus a removable central section. The floating ball closes bubble-tight against a resilient seat, and the end caps stay in the pipeline so the centre can be serviced without a line shutdown. Submit your specification to confirm body material, pressure class, end connection and inspection requirements.

Design Standards

desgin features

1. Double sealing system of packing,and firesafe design
2. Stem with emergency grease injection
3. Integral anti-blowout design structure of the stem
4. Optional locking device
5. Independent limit structure design
6. Anti-static function
7. Low torque design
8. Solid ball design
9. Unique self-relief design of the seat

General Assembly Drawing

Material of Construction

Note: Materials listed in the table are general. When ordering, please contact SNY sales or technical team to confirm the details.

Dimension &Weight

CLASS 900 Full Bore

CLASS 900 Reduced Bore

CLASS 1500 Full Bore

CLASS 1500 Reduced Bore

Inline Maintenance and Weld-In-Place Advantage

Because the end caps remain attached to the pipe, the central body can be unbolted and removed for seat, seal or ball service while the pipe run stays intact. The valve can be cleaned, inspected and rebuilt without cutting welds, draining the system or disturbing pipe alignment. In welded installations, the central body is removed before the end caps are welded to the pipe, so the heat of welding does not distort or melt the soft seats, gaskets and stem seals inside the cartridge. After welding and cooling, the centre is reassembled between the end caps. These two characteristics - service in place and weld-in-place - are the main reasons to select a 3-piece body over a two-piece body where access, downtime cost or welding sequence matter.

Floating Ball Action

In a floating design the ball is not anchored to trunnions. Upstream line pressure pushes the ball slightly downstream so it loads the downstream seat and energizes the seal. The design is self-energizing and, in its standard form, seals in the line flow direction; bidirectional shutoff requires a second upstream seat. The floating arrangement keeps operating torque moderate for the sizes covered here. For larger sizes or higher pressures, a trunnion-mounted ball is normally selected (see the floating vs. trunnion comparison).

Testing, Fire-Safe, and Anti-Static Features

Each valve is tested for shell and seat integrity. Shell test is typically 1.5 times the rated pressure and seat test 1.1 times the rated pressure, with seat leakage accepted to ISO 5208 Rate A for soft seats. Testing follows API 598, ISO 5208 or EN 12266-1 as specified.

Fire-safe: secondary metal sealing per API 607 / API 6FA maintains shutoff if the soft insert is destroyed in a fire.

Anti-static: a path between ball, stem and body (per API 608) prevents static discharge in flammable service.

Blow-out-proof stem: a shoulder retained by the body prevents stem ejection under internal pressure.

Locking and ISO 5211 pad: lockable handle or gearbox and a standard actuator mounting flange.

Fugitive emission: low-emission packing per ISO 15848 available on request.

Material traceability is documented by a Material Test Certificate to EN 10204 (3.1 as standard, 3.2 with third-party involvement on request), covering chemistry, mechanical properties, heat number and, where applicable, hardness and NACE compliance. Third-party inspection (for example SGS, BV, TUV) is supported when required by the contract.

Applications

The 3-piece forged floating soft seated ball valve is selected where periodic access to the internals is expected:

Chemical and petrochemical lines with corrosive or deposit-forming media

Pharmaceutical, food and beverage processes requiring clean-in-place (CIP) and frequent inspection

Instrument, sampling and utility lines where the valve is opened for service

Skid-mounted and modular process units welded into the package

Compressed gas, hydraulic and low-temperature systems (A350 LF2)

Sour (H2S) environments per NACE MR0175 / ISO 15156 (confirmed per conditions)

valve factory

Provide the following to receive a quotation: nominal size and pressure class, body material (for example A105 or F316), end connection (NPT, socket weld, butt weld, or flanged), seat material, bore type (full or reduced), required standards (API 608, ASME B16.34), any sour-service, low-temperature or fire-safe requirement, quantity, and destination. A line list or data sheet shortens the confirmation.

Request a Quotation

FAQ

What defines a 3-piece ball valve body?

A 3-piece ball valve body consists of two end caps and a central body section that houses the ball, seats and stem. The three parts are held together by body bolts. The end caps connect to the pipeline while the central body can be unbolted and lifted out, which is the defining feature of the design.

How does a 3-piece valve allow inline maintenance without line shutdown?

Because the two end caps stay connected to the pipe, the central body can be unbolted and removed for seat, seal or ball service while the pipe run remains intact. This avoids cutting welds, draining the system or disturbing pipe alignment, reducing downtime compared with a 2-piece valve that usually must be removed from the line.

Can the center body be removed before welding the end caps to the pipeline?

Yes. For socket-weld or butt-weld ends, the central body is removed before the end caps are welded to the pipe, so the heat of welding does not distort or melt the soft seats, gaskets and stem seals inside the cartridge. After welding and cooling, the center body is reassembled between the end caps.

Does the 3-piece body have more joints, and does that increase leakage risk?

A 3-piece body has two bolted body joints, one more than a 2-piece body and two more than a 1-piece body. These are gasketed, bolted joints designed for the service, so they do not inherently leak; the trade for inline serviceability is additional sealing surfaces and a slightly higher cost. Proper bolt torque and joint design keep the leakage acceptance to ISO 5208 Rate A for soft seats.

What soft seat materials are available, and what temperature range do they cover?

Common soft seats are PTFE (about -29 to +200 deg C), RPTFE reinforced with glass or carbon (about -29 to +230 deg C), PEEK (about -20 to +260 deg C) and Devlon nylon composite (about -20 to +220 deg C). The usable window also depends on line pressure, medium and the specific compound, so the confirmed range should be stated at quotation.

What standards and pressure classes apply to forged 3-piece floating ball valves?

Design follows API 608, with ISO 17292 and BS 5351, and pressure-temperature limits per ASME B16.34; testing follows API 598, ISO 5208 or EN 12266-1. Forged floating valves typically span NPS 1/4 to 2 (DN 8 to 50) at Class 150 through Class 1500 (PN 16 to PN 250), with Class 800 common for threaded and socket-weld ends. Larger sizes are evaluated per inquiry.

Are forged 3-piece valves suitable for sour or low-temperature service?

Forged bodies in ASTM A350 LF2 are supplied for low-temperature service, and bodies with verified chemistry and hardness control can be supplied for sour (H2S) service under NACE MR0175 / ISO 15156. Suitability depends on H2S partial pressure, chloride and hardness limits, so the service conditions must be stated at quotation.

What information should be provided when requesting a quotation?

Provide the nominal size and pressure class, body material (for example A105 or F316), end connection (NPT, socket weld, butt weld, or flanged), seat material, bore type (full or reduced), required standards (API 608, ASME B16.34), any sour-service, low-temperature or fire-safe requirement, quantity, and destination. A line list or data sheet shortens the confirmation.

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