1. Applicable Standards and Design Basis
Our GB Marine Angle Valves are designed, manufactured, and tested in accordance with the following core standards:

• GB/T 586: Marine cast steel flanged globe valves (including angle pattern).

• GB/T 590: Marine cast iron flanged globe valves (including angle pattern).

• GB/T 587: Marine bronze flanged globe valves (including angle pattern).

• GB/T 2501: Marine pipe flanges – connection dimensions and sealing surfaces for PN6, PN10, PN16, PN25.

• GB/T 600: Test and inspection of marine valves – governing shell strength and seat tightness acceptance criteria.

• GB/T 3985 / GB/T 5574: Rubber and sealing material specifications for soft-seat options.

2. Material Selection for Severe Marine Service
Materials are selected for maximum corrosion resistance and long service life in salt-laden, humid shipboard environments:

• Body & Bonnet: Options include marine-grade cast steel (e.g., ZG230-450 or ZG0Cr18Ni9), high-strength cast iron (HT200/HT250), ductile iron (QT400-18/QT450-10), or bronze (ZCuSn10Zn2). Cast iron and carbon steel bodies receive a heavy-duty two-component epoxy coating; stainless steel and bronze bodies provide inherent corrosion resistance. Bolted bonnet design allows easy internal access for maintenance.

• Trim (Seat & Disc): Renewable stainless steel (2Cr13, 304, or 316L), bronze, or monel seats and discs, lapped to provide positive metal-to-metal shutoff. For cleaner fluids, soft-seat inserts (PTFE or reinforced EPDM) are available for bubble-tight closure.

• Stem: Stainless steel (2Cr13, 304, or 316L) with external acme threads and an integral back-seat shoulder, polished for smooth operation and extended packing life.

• Packing & Gasket: Graphite or PTFE-impregnated packing rings, compressed by an adjustable gland, ensure reliable stem sealing. Bonnet gaskets are reinforced graphite, PTFE, or spiral-wound stainless steel/graphite.

3. Key Technical Features

• Angle Pattern Design: The 90-degree body layout functions as both a stop valve and a flow-direction change, reducing the number of piping components, joints, and potential leak points while saving valuable space in crowded engine rooms and pump rooms.

• Positive Back-Seating: When the valve is fully open, the stem shoulder seals firmly against a back-seat bushing in the bonnet. This allows the packing to be replaced or tightened while the valve is under pressure, providing a secondary stem seal and enhancing operational safety.

• Full-Guided Disc: The disc is guided independently within the body or by the stem, ensuring smooth, vibration-free operation even during throttling service and minimizing seat wear.

• Renewable Seating Surfaces: Seat rings and discs are designed to be replaceable, significantly extending the valve’s service life without requiring complete valve replacement.

• Manual and Actuator-Ready: Standard configuration includes a robust handwheel with a rising stem and clear open/closed position indication. Gear operators are supplied for larger sizes and higher pressures to reduce operating torque. An ISO 5211 mounting pad or adaptable top flange allows fitting of electric, pneumatic, or hydraulic actuators.

4. Typical Marine Applications

• Seawater cooling overboard discharge lines

• Fire main and foam system shutoff and isolation

• Fuel oil and lubricating oil transfer, heater inlet/outlet isolation

• Boiler feedwater, condensate, and steam line drains and vents

• Compressed air and control air distribution headers

• Bilge, ballast, and stripping pump suction/discharge

• Tank suction and cross-connection valves

5. Quality Assurance, Testing, and Certification

• Testing: Every valve undergoes a hydraulic shell test at 1.5 times the rated pressure and a seat leakage test at 1.1 times the rated pressure, strictly in accordance with GB/T 600. Back-seat tests are performed where applicable. Test certificates are supplied with each shipment.

• Material Traceability: Full EN 10204 Type 3.1 (or equivalent GB) material certificates are provided for the body, bonnet, stem, and trim components. Permanent markings include manufacturer’s name, nominal size (DN), pressure rating (PN), body material, heat number, and standard reference per applicable marking requirements.

• Class Approvals: Our GB Marine Angle Valves can be supplied with type approval certificates from all major IACS classification societies (CCS, DNV, LR, BV, ABS, NK, KR, RINA, etc.), ensuring immediate acceptance during newbuilding and repair surveys.