Hinged Expansion Joint

A unidirectional hinged angular bellows expansion joint consists of a single bellows, a pair of hinged ear plates, a pin, and support components. Thanks to its hinged structure, it allows angular deflection only within a single plane, thereby absorbing angular displacement in the pipeline; the hinged structure can withstand the full thrust generated by the internal pressure of the pipeline, confining the thrust within the hinged frame so that it is not transmitted to the pipeline equipment.

Usage Guidelines: Must be used in pairs; a single unit cannot independently accommodate pipeline thermal displacement.

Product Structure

Stainless steel bellows: 304 / 316L / 321; special alloys available upon request

Hinge ear plates and pin assembly (pressure-bearing components)

End connections / flanges: welded or flanged connections

Shipping stop bolts (factory-installed protection; to be removed after installation)

Product Advantages

1. The hinges bear internal pressure thrust, protecting equipment such as pumps and heat exchangers from thrust impacts

2. Allows only single-plane angular rotation while restricting axial and lateral displacement, resulting in a more stable piping system

3. High structural rigidity, vibration resistance, and excellent fatigue life

4. Excellent adaptability for large-diameter and high-temperature applications; widely used in power plant flue ducts and thermal pipelines

Applicable Conditions

L-shaped and Z-shaped pipe sections where the piping system experiences angular displacement in a single plane;

Recommended: Power plant boiler flue ducts, thermal steam pipelines, and high-temperature chemical pipelines

Not Suitable: For standalone use or applications requiring absorption of lateral displacement or multi-directional angular displacement (select the Hinged Expansion Joint type for multi-directional angular displacement)

Technical Specifications

Selection & Installation Guidelines

1. Key Requirement: Single-hinged angular expansion joints must be used in pairs; a single unit cannot compensate for thermal expansion on its own.

2. The hinge pins are load-bearing components; striking, cutting, or removing them is strictly prohibited.

3. Remove the shipping restraint bolts prior to installation; the unit must not be operated while these restraints are in place.

4. The design of the pipe supports must align with the plane of hinge rotation to prevent the introduction of unintended lateral loads.

Competitive Advantages

Unlike standard component manufacturers, we specialize in providing comprehensive engineering solutions for oil refining and petrochemical EPC projects, rather than merely supplying hardware. Our core differentiators include:

1. Integrated Engineering Capabilities: We handle all design work in-house, including fatigue analysis for expansion joints, load verification for spring supports (per MSS SP-58), finite element analysis (FEA), and 2D fabrication drawings. We also provide neutral 3D models (IGES/SAT formats) to facilitate interference checks during the client’s final assembly—a capability many competitors lack, as they often provide only the physical products.

2. Comprehensive Documentation Expertise: We are well-versed in the full range of project documentation requirements. We can prepare Welding Procedure Specifications (WPS) and Procedure Qualification Records (PQR), develop Inspection and Test Plans (ITP), and assist in compiling technical dossiers for EAC/COC certification.

3. Clearly Defined Service Scopes by Project Phase: During the bidding and estimation stage, we provide standard data sheets and general schematic drawings. Formal calculation reports and project-specific drawings are issued upon order confirmation. We support both new project supply and the provision of replacement parts for refinery turnarounds, with clear, well-defined protocols for document delivery.

4. Proven Track Record in Complex, Critical Applications: We possess extensive experience with FCC catalyst piping, large-diameter expansion joints, and multi-ply high-alloy bellows (e.g., Inconel 625, Hastelloy). For oversized or heavy components, we utilize mature export-grade steel crating solutions, optimized for ocean freight via break-bulk or flat-rack containers.

5. Large-Scale Order Management and Flexible Delivery: We are equipped to handle large-scale projects involving a diverse mix of specifications. Backed by a stable raw material supply chain, we prioritize production for major orders and offer phased shipments aligned with site construction schedules. We ensure consistent quality control across entire batches and provide comprehensive batch-specific documentation.

6. Full-Lifecycle Technical and Inspection Support: We offer 24-hour rapid technical response, facilitate client or third-party witness inspections during production, and provide thorough installation guidance and post-delivery technical consultation.