Description

Technical Data Sheet: 48″ (DN1200) ASME Class 300 Fully Welded Trunnion-Mounted Ball Valve (WCB Body)

1. Product Overview

This product is a 48-inch (DN1200), ASME Class 300 Fully Welded Trunnion-Mounted Ball Valve equipped with a double-acting pneumatic actuator. The valve body is constructed from ASTM A216 WCB cast carbon steel, as indicated by the nameplate markings (48″, 300LB, WCB, D363H). The valve features a monolithic fully welded body construction with a trunnion-supported ball mechanism, designed to meet the requirements of API 6D and ASME B16.34 standards.

The fully welded body design eliminates the risk of leakage from body joints, providing long-lasting performance in harsh environments. The trunnion-mounted ball is supported by both ends, which significantly reduces stress on the valve components during operation and allows for easy operation at high pressures compared to floating ball valves. The valve is equipped with a double-acting pneumatic actuator for reliable, rapid, and automated quarter-turn operation, making it suitable for critical isolation duties in oil and gas transmission pipelines, compressor stations, and power plant systems.

This data sheet corresponds to the product nameplate markings: 48″, 300LB, WCB, D363H.

2. Technical Specifications

Note: WCB material is rated for service from -29°C to 425°C. Below -29°C, low-temperature carbon steel (ASTM A352 LCB) should be specified. Above 425°C, creep becomes a concern and alloy steel castings are required.

3. Main Component Materials

4. Design Features

4.1 Fully Welded Body Construction

The valve features a monolithic fully welded body that eliminates all body joint flanges and gaskets. This design removes potential leak paths to the external environment, ensuring reliable protection of the entire system and making the valve suitable for critical isolation services in harsh environments.

4.2 Trunnion-Mounted Ball Design

The ball is supported by trunnion bearings at both ends (top and bottom), which reduces the load on the valve seats and extends the valve’s lifespan. The trunnion design reduces operating torque by 60-70% compared to floating ball valves, making it easier to automate or control manually.

4.3 Double Block and Bleed (DBB) Capability

The valve is equipped with a double block and bleed (DBB) design, which provides isolation of fluid on both sides of the valve and allows safe venting of trapped pressure from the body cavity. This feature enables verification of seat integrity while the valve is in service.

4.4 Self-Relieving Seats

The seats are designed with a self-relieving (self-bleeding) feature that automatically relieves pressure build-up inside the valve cavity. This ensures safety and prevents damage from overpressure caused by thermal expansion of trapped fluid.

4.5 Fire-Safe Design

The valve is equipped with a fire-safe design tested to API 607 and API 6FA standards. In the event of a fire, the graphite secondary seal ensures valve integrity and prevents media leakage.

4.6 Anti-Static Device

An anti-static device is installed between the body, ball, and stem to ensure electrical continuity and prevent static electricity buildup. The electrical resistance between metallic components is ensured to be below 10 Ohm.

4.7 Anti-Blowout Stem

The stem is designed with an anti-blowout feature to prevent it from being ejected under abnormal pressure conditions, ensuring operational safety.

4.8 Double-Acting Pneumatic Actuator

The valve is operated by a large double-acting pneumatic actuator mounted via a heavy-duty lever linkage or direct mount. The actuator provides high output torque required for large-diameter, high-pressure class ball valves. It allows for remote open/close control and can be integrated with a positioner for modulating service.

5. Dimensional Reference

48″ (DN1200) ASME CLASS 300

Note: Face-to-face dimension is based on API 6D / ASME B16.10 long pattern for flanged end valves. Flange dimensions are per ASME B16.5 Class 300. Actual dimensions may vary slightly by manufacturer. Please refer to the certified drawing for exact dimensions.

6. Pressure Test

Inspected and tested in accordance with API 598 and API 6D:

Note: The shell test is 1.5 times the Cold Working Pressure (CWP) at ambient temperature. For ASME Class 300, the CWP is 51.1 bar (740 psi). The seat test is 1.1 times the CWP. Per API 598, the shell test pressure for Class 300 is approximately 76.7 bar (1,110 psi), and the seat test pressure is approximately 56.2 bar (815 psi).

7. Chemical and Mechanical Properties (WCB)

Note: WCB is the cast equivalent of ASTM A105 forged steel. Both serve carbon steel piping systems operating at ambient to moderately elevated temperatures. The material pairs with ASTM A105 forged components (flanges, small-bore valves) and carbon steel pipes in grades A106 B, A53, and API 5L.

8. Actuator Specifications

Note: Pneumatic actuator torque output can range from 8 Nm to 4,678 Nm for double-acting types, depending on the specific actuator model and air supply pressure. The actuator should be sized to provide a minimum safety factor of 1.5 times the valve breakaway torque.

9. Installation & Operation Instructions

1. Installation Orientation: The valve can be installed in horizontal or vertical pipelines. For horizontal pipelines, the stem should be oriented horizontally or vertically (preferred) to ensure proper bearing lubrication. Ensure adequate clearance for the actuator and linkage movement.

2. Flow Direction: The valve is bi-directional, but the preferred flow direction is indicated by the arrow on the body. Install the valve so that the arrow points in the direction of normal flow for optimal sealing performance.

3. Pipeline Cleaning: Thoroughly clean the piping system before installation to remove welding slag, debris, or foreign objects that could damage the ball and seat sealing surfaces.

4. Welding or Flange Connection: For butt weld ends, follow qualified welding procedures to avoid overheating the valve internals. For flanged ends, use appropriate gaskets and tighten the flange bolts evenly in a cross-pattern.

5. Actuator Connection: Connect the air supply and control signal wiring according to the actuator manufacturer’s instructions. Ensure the air supply is clean and dry. Adjust the limit switches to match the fully open and fully closed positions.

6. Double Block and Bleed: Use the body cavity bleed valve to verify seat integrity. With the valve in the closed position, open the bleed valve to vent any trapped pressure. If flow continues, the seat may be damaged.

7. Maintenance: Periodic inspection of the ball and seat is recommended. The fully welded body design does not allow for inline maintenance of internal components; the valve must be removed from the pipeline for major repairs. Ensure the pipeline is depressurized and drained before any maintenance activity.

10. Applications

• Oil and natural gas transmission pipelines

• Compressor stations and pump discharge lines

• Power plant steam and feedwater systems

• Large-diameter water and cooling water pipelines

• Industrial piping systems requiring zero-leakage isolation

• High-pressure and high-temperature isolation duties

• LNG transfer and sour gas service (with appropriate trim and NACE compliance)

11. Ordering Information

Please provide the following information when ordering:

1. Nominal Size (NPS / DN)

2. Pressure Rating (ASME CLASS)

3. Body Material (WCB / LCB / CF8M, etc.)

4. Ball / Stem / Seat Material (F316 + ENP / RPTFE / Devlon, etc.)

5. Connection Type (RF / RTJ / BW)

6. Bore Type (Full Bore / Reduced Bore)

7. Operation Type (Double-Acting Pneumatic / Spring-Return / Electric / Hydraulic)

8. Actuator Specifications (Air Supply, Control Signal, Positioner, Limit Switches, Manual Override, etc.)

9. Special Requirements (NACE MR0175, Fire-Safe Certification, Anti-Static Device, Double Block & Bleed, SIL Certification, Certification Requirements, etc.)