Introduction: The Vital Role of Valves on Tankers
Valves are among the most important components onboard oil and chemical tankers. They control, isolate, and direct the flow of liquids such as crude oil, refined petroleum products, and chemicals—ensuring safe loading, transfer, and discharge operations.
Given the hazardous nature of these cargoes, the correct valve type, material, and design are critical for safety, reliability, and environmental compliance.
As a leading marine and industrial valve stockist based in Singapore, Aik Soon Hardware supplies a wide range of valves that meet the demanding requirements of tanker vessels. This article explores the most common valve types found onboard tankers, where they are used, and what to consider when selecting them.
1. Gate Valves
Description:
Gate valves use a wedge-shaped gate to control flow, moving vertically to open or close the passage. They are best suited for on/off applications, offering minimal pressure drop when fully open.
Use Case:
Material Selection:
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Bronze or stainless steel for seawater and ballast lines
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Carbon steel for cargo and fuel transfer lines
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Duplex stainless steel for corrosive cargoes or chemical applications
Location on Tankers:
Commonly found in cargo manifolds, ballast manifolds, and pump rooms, where robust shut-off is required.
Selection Tip:
Choose gate valves when tight isolation and low flow resistance are essential. However, avoid using them for throttling as it can damage the seating surfaces.
2. Globe Valves
Description:
Globe valves regulate flow using a movable plug that adjusts against a stationary seat. They are designed for throttling and precise flow control.
Use Case:
Material Selection:
Location on Tankers:
Typically found in engine rooms, boiler systems, and steam tracing systems, where controlled flow regulation is needed.
Selection Tip:
Globe valves are best when flow regulation is required rather than simple on/off operation. Ensure compatibility with the system’s temperature and pressure class.
3. Ball Valves
Description:
Ball valves use a spherical disc with a hole through it, which rotates to start or stop flow. They offer quick quarter-turn operation and excellent sealing performance.
Use Case:
Material Selection:
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316 stainless steel for corrosive cargoes
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Carbon steel for general oil transfer
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PTFE or Viton seats for chemical resistance
Location on Tankers:
Widely used in cargo transfer systems, bunker manifolds, and hydraulic control lines where quick, reliable shut-off is needed.
Selection Tip:
Ball valves are preferred for fast actuation and tight sealing in cargo and fuel applications. For chemical tankers, use non-sparking materials and antistatic designs for safety.
4. Butterfly Valves
Description:
Butterfly valves use a rotating disc inside the valve body to regulate or shut off flow. They are lightweight, compact, and ideal for large-diameter pipelines.
Use Case:
Material Selection:
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Marine bronze or stainless steel for seawater lines
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Epoxy-coated ductile iron for general services
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PTFE-lined valves for chemical service
Location on Tankers:
Typically found in ballast manifolds, firefighting systems, and vent lines where space-saving and ease of operation are important.
Selection Tip:
Select butterfly valves when weight and space are concerns. Ensure the seat and body materials are suitable for corrosive seawater or chemical vapors.
5. Check Valves
Description:
Check valves prevent reverse flow, automatically closing when fluid flow stops or reverses. They protect pumps, compressors, and pipelines from backflow damage.
Use Case:
Material Selection:
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Bronze or stainless steel for seawater or chemical compatibility
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Carbon steel for oil service
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Monel or duplex steel for corrosive cargo applications
Location on Tankers:
Installed in pump discharge lines, engine cooling systems, and cargo transfer lines to maintain one-way flow.
Selection Tip:
When choosing check valves, consider the flow rate, cracking pressure, and the orientation (vertical or horizontal) of the pipeline.
6. Relief & Safety Valves
Description:
These valves automatically release pressure when it exceeds a set limit, protecting systems from overpressure or explosion hazards.
Use Case:
Material Selection:
Location on Tankers:
Installed on cargo tanks, pump rooms, boilers, and pressure vessels to maintain safety and compliance with IMO and SOLAS standards.
Selection Tip:
Safety valves must comply with relevant marine class certifications (e.g., ABS, DNV, BV) and be regularly inspected for proper calibration.
Selecting the Right Valve for Tankers
When selecting a valve for tanker operations, consider:
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Cargo Type: Oil, chemical, or gas cargoes have different compatibility requirements.
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Operating Pressure & Temperature: Match the valve’s pressure class and materials accordingly.
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Corrosion Resistance: Marine and chemical environments demand materials like 316 stainless steel, bronze, or duplex steel.
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Class & Standards: Ensure valves comply with IMO, IACS, and marine classification society requirements.
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Maintenance & Accessibility: Opt for designs that simplify inspection and replacement, especially in confined spaces.
At Aik Soon Hardware, our team supports ship owners, operators, and marine engineers in selecting valves that meet both operational and regulatory requirements.