TECHNICAL DATA SHEET
Product: DBB Double Block & Bleed Ball Valve
Size: 1 inch (DN25)
Pressure Class: Class 1500
Design: Double Ball in Series, Integral Body
End Connections: One End NPT (Female) / Opposite End Flanged
- Basic Specifications
Parameter | Value |
Nominal Size | 1″ (DN25) |
Pressure Rating | Class 1500 (PN250) |
Valve Design | Double Block & Bleed (DBB) – two ball valves in series with integral bleed port |
End Connections | Upstream: NPT Female (per ASME B1.20.1) Downstream: Flanged – ASME B16.5 Class 1500 (RF or RTJ) |
Temperature Range | –29°C ~ +500°C (depending on seat material) |
Suitable Media | High-pressure gas/liquid, steam, corrosive fluids |
Fire Safe Design | API 607 / ISO 10497 |
- Features & Functionality
- DBB Functionality (Double Block & Bleed): Two independent ball valves in series with a bleed port between them. When both valves are closed, the intermediate cavity can be vented or monitored, providing positive double isolation from both upstream and downstream sides.
- Integral Body Construction: Both ball valves share a single compact body, minimizing potential leak paths and reducing installation space.
- Blowout-Proof Stem: Each ball valve is equipped with a blowout-proof stem for safe operation under high pressure.
- Versatile Seating Options: Available with soft seats (PTFE / PEEK) or metal seats (tungsten carbide / Stellite) to suit high-temperature, high-pressure, or abrasive media applications.
- Operating Modes: Can be fitted with hand levers, gear operators, pneumatic actuators, or electric actuators; the two ball valves can be operated independently or simultaneously.
- Material List (Recommended High-Pressure / High-Temperature Configuration)
Item | Part | Standard Material |
1 | Body | A105N (ASTM A105 Normalized) / F316 |
2 | Ball (2 pcs) | A105N + Tungsten Carbide Coating / 316SS + Tungsten Carbide Coating |
3 | Seat Rings (2 sets) | 316SS + Stellite 21 Hardfacing |
4 | Stems (2 pcs) | 17-4PH / Inconel 718 |
5 | Stem Packing | Flexible Graphite + Braided Graphite |
6 | Body Gasket | Spiral Wound, SS + Graphite |
7 | Bleed / Test Port | 1/2″ NPT or Socket Weld |
8 | Bolting | A193 B7 / A194 2H |
Note: NACE MR0175 compliant materials are available for sour service applications.
- Dimensions & Structural Data
Parameter | Value |
Face-to-Face Length (L) | ~280 – 320 mm (varies by design; confirm with drawing) |
Flange End | ASME B16.5 Class 1500 – Raised Face (RF) or Ring Type Joint (RTJ) |
NPT End | 1″ NPT Female per ASME B1.20.1 |
Bleed Port Size | 1/2″ NPT or 1/2″ Socket Weld |
Top Height (H) | ~220 mm (with hand lever) |
Operating Torque (per ball) | ~80 – 150 N·m |
Approx. Weight | ~22 – 30 kg (mixed end configuration) |
Note: Final dimensions to be confirmed by manufacturing drawings.
- Design & Testing Standards
Item | Standard |
Design & Manufacture | API 6D (DBB Valves) / API 608 / ASME B16.34 |
NPT End | ASME B1.20.1 |
Flanged End | ASME B16.5 |
Pressure-Temperature Rating | ASME B16.34 |
Fire Safe Test | API 607 or API 6FA |
Pressure Testing | API 598 or ISO 5208 |
Low-Pressure Air Test | 0.6 MPa (6 bar) – no visible leakage |
High-Pressure Hydrostatic Test | 1.5 × rated pressure (body), 1.1 × rated pressure (seat) |
DBB Functional Test | With both balls closed and bleed port open, no leakage from upstream or downstream |
- DBB Functionality Description
The Double Block & Bleed configuration is essential for applications requiring absolute isolation:
- Instrument Isolation: Provides safe isolation and venting for pressure transmitters, flow meters, and other instruments, enabling maintenance without process interruption.
- Sampling Systems: Allows safe fluid sampling by double isolation and intermediate venting, preventing hazardous media exposure.
- High-Pressure Gas Systems: Ideal for natural gas, hydrogen, and other high-pressure gases where positive shut-off is critical.
- Online Maintenance: Enables isolation of a pipeline section without draining the entire system.
- Operating Torque & Actuator Sizing
- Simultaneous Operation: If both ball valves are to be operated together (e.g., with a single actuator or geared linkage), total torque is approximately the sum of individual ball torques.
- Independent Operation: If each ball is operated separately, size actuators per individual ball torque.
- High-Temperature & Metal Seated: Metal seated configurations generate higher torque due to thermal expansion; actuator output torque should be at least 1.3 ~ 1.5 times the maximum measured valve torque.
- Typical Applications
- Oil & gas pipelines and station piping
- Refinery instrument impulse line isolation
- Chemical plant sampling systems
- High-pressure hydraulic test benches
- Hydrogen refueling station high-pressure circuits
This data sheet reflects the specified configuration: 1″ Class 1500 DBB valve with one NPT end and one flanged end. For customized materials (e.g., duplex, Inconel), NACE compliance, or automated actuation, please contact us for further details.
GUATANTEE:
SAVVY VALVES is committed to delivering exceptional product quality and worry-free after-sales service. Our valves are guaranteed to provide a minimum service life of 12 months, during which we will supply all necessary spare parts and detailed maintenance instructions free of charge. Within the warranty period, if any non-human-induced damage occurs, we will replace components at no cost and provide professional technical support. After the warranty expires, customers only need to pay for the cost of spare parts, while still benefiting from discounted maintenance services. Our goal is to help clients reduce operational costs and enhance production efficiency through reliable quality and comprehensive after-sales support. Whether for technical inquiries or maintenance needs, our expert team will respond promptly to ensure your valve system maintains optimal performance at all times.