1. PRODUCT OVERVIEW

The CB/T 3942-2002 Stainless Steel Flanged Stop Valve is a marine-grade globe valve designed for shipboard piping systems carrying corrosive and non-corrosive media. This standard is issued by the National Defense Science and Technology Industry Commission of the People's Republic of China. The valve features a flange connection design and is constructed from high-grade stainless steel (SUS 304 equivalent) for excellent corrosion resistance in harsh marine environments.

This standard applies to stop valves used in piping systems of liquefied gas carriers, bulk chemical carriers, and naval vessels with nominal pressures not exceeding 6.4 MPa and design temperatures not lower than -165°C. Stop valves for corrosive media in other ship piping systems may also refer to this standard.

Key Design Characteristics:

• Flanged connection with sealing surface per CB/T 569 or CB/T 2501

• Stainless steel construction (SUS 304 / 022Cr19Ni10) for superior corrosion resistance

• Straight-through and right-angle configurations available

• Manual handwheel operation with reliable shut-off and throttling capability

• Suitable for low-temperature service down to -165°C

2. WORKING PRINCIPLE

The globe valve operates through a linear motion mechanism. The stem axis is perpendicular to the seat sealing surface. The valve disc is connected to the stem and moves vertically to open or close the flow passage. When the handwheel is turned, the stem rises or lowers the disc, which engages or disengages with the seat ring.

Key operational features:

• Short stroke: The valve stem travel is relatively short, enabling quick opening and closing.

• Reliable shut-off: The disc and seat make contact only in the closed position, resulting in minimal mechanical wear on the sealing surfaces.

• Throttling capability: The valve is suitable for both isolation and flow regulation applications.

• Easy maintenance: The seat and disc sealing elements can be repaired or replaced without removing the entire valve from the pipeline in most configurations.

• Flow direction: The flow direction is typically indicated by an arrow on the body. Globe valves can be installed in either direction but are most effective when flow enters from the seat side.

3. DESIGN & MANUFACTURING STANDARDS

Design Standard: CB/T 3942-2002
Testing Standard: API 598 / ISO 5208

4. MATERIALS OF CONSTRUCTION

Note: The disc may be machined from the same material as the body or from a suitable corrosion-resistant alloy.

5. PRESSURE & TEMPERATURE RATINGS

The maximum allowable working pressure (MAWP) varies with the operating temperature as specified in Table 1 of the standard.

TABLE 1 – MAXIMUM ALLOWABLE WORKING PRESSURE (MPa)

Note: For AS and BS series, the same pressure-temperature ratings apply as for A and B series.

6. SIZE RANGE

7. DIMENSIONS

TABLE 2 – BASIC DIMENSIONS FOR PN 1.0, 1.6, AND 2.5 MPa (TYPE A AND B) (Unit: mm)

TABLE 3 – BASIC DIMENSIONS FOR PN 4.0 AND 6.4 MPa (TYPE A AND B) (Unit: mm)

8. KEY FEATURES & BENEFITS

9. TYPICAL APPLICATIONS

• Liquefied Gas Carriers – Cargo and process piping systems

• Bulk Chemical Carriers – Corrosive media handling

• Naval Vessels – Seawater, fresh water, fuel oil, and lubricating oil systems

• Marine Engine Rooms – Cooling water, fuel oil, and lubricating oil lines

• Offshore Platforms – Process and utility piping

• Shipbuilding – General piping systems requiring corrosion-resistant valves

10. ORDERING INFORMATION

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