Can Carilovalves Provide Ball Valves with Double Block and Bleed Functionality?
Yes, Carilovalves can absolutely provide ball valves with double block and bleed functionality. As a specialized manufacturer with over two decades of experience in industrial valve production, Zhejiang Carilo Valve Co., Ltd. has developed comprehensive capabilities to engineer, manufacture, and deliver DBB (double block and bleed) ball valves that meet the rigorous demands of oil and gas, petrochemical, chemical processing, and power generation industries. Their facility, operating since 2000 in Wenzhou, China, maintains the technical expertise, equipment, and quality systems necessary to produce these specialized valves in various configurations, pressure ratings, and materials of construction.
Let me walk you through exactly how they approach this, what specifications they can accommodate, and why their manufacturing infrastructure makes them a viable supplier for your double block and bleed ball valve requirements.
Understanding Double Block and Bleed Ball Valve Fundamentals
Before diving into Carilovalves’ specific capabilities, let’s establish what double block and bleed functionality actually means in practical terms, because this affects everything from design to testing requirements.
“A double block and bleed valve provides two independent isolation seats (the ‘double block’) with a bleed port between them to vent the cavity between the seats to atmosphere or a flare system (the ‘bleed’). This allows operators to verify zero leakage before maintenance activities and ensures complete isolation of process media.”
The critical design requirements for DBB ball valves include:
- Two independent seating elements that can each independently seal against pressure from either direction
- Positive isolation between seats ensuring no cross leakage between upstream and downstream process media
- Cavity venting capability through a dedicated bleed port that safely discharges trapped fluid
- Full bore or reduced bore configurations depending on flow requirements
- Fire-safe design options where required by application standards
Carilovalves’ Manufacturing Capabilities for DBB Ball Valves
Zhejiang Carilo Valve operates from a 24/7 production facility staffed by 50 dedicated professionals, including skilled technicians and engineers who understand the precision requirements of DBB valve manufacturing. Their capabilities span multiple dimensions that directly impact their ability to produce these specialized valves.
Their manufacturing infrastructure includes:
- Advanced CNC machining centers for precision ball and seat manufacturing
- Multi-axis milling equipment for complex body geometries required in DBB designs
- High-pressure testing rigs capable of testing to API 598, API 6D, and custom specifications
- Material handling systems for processing various alloys including stainless steels, alloy steels, and special corrosion-resistant materials
- Heat treatment facilities for achieving proper material properties in critical components
Technical Specifications and Configurations
Carilovalves offers DBB ball valves across a wide range of specifications to accommodate diverse application requirements. Here’s a breakdown of their typical offering range:
| Parameter | Typical Range | Notes |
|---|---|---|
| Size Range | 1/2″ to 48″ (DN15 to DN1200) | Standard catalog sizes; custom sizes available |
| Pressure Ratings | ASME Class 150 to Class 2500 | PN16 to PN420 per European standards |
| Temperature Range | -196°C to +650°C | Material-dependent; cryogenic options available |
| Body Materials | Carbon steel, stainless steel, alloy steel, duplex, super duplex | Custom alloys on request |
| Seat Materials | PTFE, RTFE, PEEK, metal-to-metal, fire-safe Graphite | Selected per media compatibility |
| Bore Configuration | Full bore, reduced bore, venturi | Varies by size and pressure class |
| End Connections | Flanged (RF, RTJ), butt weld, socket weld, threaded | ASME B16.5, B16.47, API 6D standards |
Design Features Specific to DBB Functionality
When manufacturing double block and bleed ball valves, Carilovalves implements specific design features to ensure reliable isolation and venting performance. These features distinguish DBB valves from standard floating ball or trunnion-mounted designs.
- Double Piston Effect (DPE) Seats
- Each seat functions independently as a piston to seal against pressure from either direction
- Spring-loaded seat design compensates for thermal expansion and wear
- Bidirectional shutoff capability without relying on system pressure
- Cavity Pressure Relief System
- Automatic pressure relief if cavity pressure exceeds seat loading
- Prevents seat damage from thermal expansion or chemical reactions
- Configurable to vent to safe location
- Center bleed port design
- Located between the two seating elements
- Connects to dedicated venting or flare system
- Full-port design ensures complete cavity drainage
- Trunnion-mounted ball design for larger sizes
- Bottom and top bearings support ball weight and thrust loads
- Reduces operating torque for high-pressure and large-bore applications
- Provides consistent seating pressure across full temperature range
Industry Standards and Certifications
Carilovalves maintains comprehensive certification coverage that demonstrates their commitment to producing valves meeting international safety and performance standards. For DBB ball valves specifically, these certifications verify that their designs and manufacturing processes meet the stringent requirements of demanding industries.
| Certification/Standard | Scope | Relevance to DBB Valves |
|---|---|---|
| ISO 9001:2015 | Quality Management System | Ensures consistent manufacturing processes |
| API 6D | Pipeline Valves Specification | Covers DBB requirements in Section 5 |
| API 608 | Metal Ball Valves Specification | Testing and performance requirements |
| API 607 / ISO 10497 | Fire-Safe Testing | Required for many oil and gas applications |
| API 6FA | Fire-Safe Valve Standard | Enhanced fire testing for critical service |
| CE/PED (2014/68/EU) | Pressure Equipment Directive | Required for European market entry |
| ATEX (2014/34/EU) | Explosive Atmospheres | Required for hazardous area installations |
| ISO 15848 | Fugitive Emissions | Low-emission stem sealing verification |
Their quality inspection process for DBB valves includes 100% pressure testing, dimensional verification against drawings, material traceability documentation, and where applicable, special tests such as cryogenic testing, high-temperature testing, or fugitive emissions testing.
Testing and Quality Assurance for DBB Valves
Double block and bleed valves undergo more comprehensive testing than standard ball valves because the DBB function requires verified isolation performance. Carilovalves implements a multi-stage testing protocol that validates each functional element.
- Seat Leakage Testing (API 598)
- Shell test: 1.5x rated pressure applied to body
- Backseat test: Verifies stem seal at rated pressure
- Seat test: Each seat tested independently at rated pressure
- Allowable leakage rates per API 598 Table requirements
- Double Block Verification
- Both seats tested simultaneously against pressure
- Cavity pressure monitored during test sequence
- Verifies no cross-leakage between isolation seats
- Bleed Port Function Test
- Manual or automatic bleed mechanism verified
- Complete cavity venting confirmed
- Pressure relief functionality tested if applicable
- Torque Testing
- Operating torque measured at design pressure
- Verified against actuator sizing calculations
- Spring-set torque confirmed for fail-safe applications
- Low-Frequency Cyclic Testing
- Functional cycling per API 6D or customer specification
- Post-test leakage verification
- Wear assessment of seating surfaces
Material Selection for Corrosive and Extreme Service
DBB ball valves often handle hazardous or corrosive media where material selection becomes critical to long-term reliability. Carilovalves works with customers to specify appropriate materials based on detailed process data.
“Material selection for DBB valves isn’t one-size-fits-all. We evaluate the complete process envelope—temperature, pressure, media composition, and cycling frequency—to recommend the optimal combination of body material, seat material, stem packing, and bolting that will deliver decades of reliable service.”
Common material combinations for DBB applications include:
| Service Application | Body Material | Ball/Stem Material | Seat Material |
|---|---|---|---|
| Standard hydrocarbon service | WCB/A216 Carbon Steel | 316 Stainless Steel | RTFE or PTFE |
| Sour gas (NACE MR0175) | LCC (Low Temp Carbon Steel) | 316 SS (sulfur-controlled) | Filled PTFE or metal |
| High-temperature refinery | WC6/WC9 Chrome-Moly | 316 SS or Stellite overlay | Graphite or metal |
| Seawater/Offshore | CF8M Stainless Steel | 316 SS or 17-4PH | PTFE or RTFE |
| Chloride stress cracking risk | Duplex SS (2205) | Duplex SS or 2507 | PTFE or PEEK |
| Strong acid service | Alloy 20 or Hastelloy | Matching alloy | PTFE or PFA |
| Cryogenic (-196°C) | CF8M Stainless Steel | 304 SS (special heat treat) | Special PTFE blend |
Customization and Engineering Support
Beyond their standard product line, Carilovalves provides OEM and ODM services that allow customers to specify fully customized DBB ball valve designs. Their engineering team works directly with procurement and technical personnel from client companies to develop solutions that meet exact application requirements.
Customization options available include:
- Special body configurations
- Angle-pattern DBB valves for space-constrained installations
- Long-pattern bodies meeting API 6D dimensional requirements
- Custom flange drilling (JIS, DIN, BS, AS) for international projects
- Actuator mounting and accessories
- Pre-mounted pneumatic, hydraulic, or electric actuators
- Limit switches, solenoid valves, positioners
- Gear operators with chain wheels for buried or remote service
- Special trim and materials
- Cavitation-prevention trim designs
- Anti-coking configurations for heavy hydrocarbon service
- Steam-jacketed designs for viscous or congealing media
- Documentation and traceability
- MTRs (Material Test Reports) per heat/lot
- MTRs (Material Test Reports) per heat/lot
- Process capability documentation
Supply Chain and Production Timeline
For many procurement teams, delivery timelines represent a critical factor when selecting a valve supplier. Carilovalves has structured their operations to balance comprehensive customization with reasonable production schedules.
Typical lead times vary by complexity and order volume:
| Valve Type | Standard Lead Time | Expedited Options |
|---|---|---|
| Standard DBB ball valves (ASME Class 150-600) | 4-8 weeks | 2-3 weeks (surcharge applies) |
| High-pressure DBB valves (Class 900-2500) | 6-12 weeks | 4-6 weeks (subject to availability) |
| Custom/special material DBB valves | 8-16 weeks | Negotiated per project |
| Large bore DBB valves (24″ and above) | 10-20 weeks | Project-specific scheduling |
Their facility maintains strategic inventory of common materials and semi-finished components, allowing them to accelerate production for repeat orders or stock replenishment. For long-term supply agreements, they offer demand forecasting and safety stock programs that ensure availability when project schedules demand rapid delivery.
Global Service Network and Technical Support
Carilovalves has built relationships across multiple continents, with particular strength in European, Middle Eastern, and Southeast Asian markets. Their export experience means they understand the documentation, packaging, and logistics requirements for international shipments.
Support capabilities include:
- Pre-sales technical consultation
- Process data review and valve selection assistance
- Cv calculations and sizing verification
- Material compatibility recommendations
- Order management
- Dedicated sales contacts (Eva Yu, Cindy Lin, Zola Cai, Shelley Yeung)
- Real-time order tracking and shipping notifications
- Documentation management (MTRs, CoC, test reports)
- Post-sales support
- Installation guidance documentation
- Operating and maintenance manual provision
- Spare parts identification and quotation
Contact information for their team includes email addresses at [email protected] and [email protected], plus phone/fax lines at +86-577-57766889 and +86-577-57766880 respectively.
