Integrally vulcanized non-metallic expansion joint

Integrally Vulcanized Non-Metallic Expansion Joint Overview

An integrally vulcanized non-metallic expansion joint is a flexible movement-compensation component designed for flue-gas, hot-air, ventilation, dust-collection and environmental-treatment duct systems.

The reinforced flexible element accommodates movement caused by thermal expansion, equipment vibration and installation variation. It can be engineered to absorb axial, lateral, angular and selected combined movements.

The sealing elastomer and reinforcement materials are combined and formed into a continuous vulcanized flexible element. This construction can reduce splice interfaces in the flexible section and support consistent sealing across the movement area.

Key Features

• Continuous integrally vulcanized flexible construction
• Accommodates axial, lateral, angular and combined movement
• Helps isolate vibration from fans and connected equipment
• Reduces structural noise and loads transferred to adjoining ductwork
• Requires relatively short installation length
• Available for round, rectangular and custom duct openings
• Material combinations can be selected for temperature and media conditions
• Available with project-specific frames, liners and connection arrangements

Construction

The assembly generally consists of an integrally vulcanized flexible element, metal connection frames, clamping plates or fastening components, and any required flow liner, insulation or accumulation-control structure.

The flexible element accommodates movement and maintains the system seal. The metal frame connects the expansion joint to the ductwork or equipment.

For high-temperature, high-velocity, dusty or abrasive service, an internal flow liner may be incorporated to reduce direct impingement and abrasion on the flexible material.

Integrally Vulcanized Flexible Element

The sealing elastomer and reinforcement layers are combined and vulcanized as a continuous flexible component. The arrangement can reduce local discontinuities associated with spliced flexible sections.

The actual number of layers, reinforcement construction, elastomer type and manufacturing process should be selected according to temperature, medium, pressure conditions, movement and required service life.

Material Options

Depending on project conditions, the flexible element may incorporate temperature-resistant elastomers, coated reinforcement fabrics, fluoropolymer-based barriers, glass-fibre reinforcement or other engineered composite materials.

Connection frames, clamping bars and internal liners can be manufactured from carbon steel, stainless steel or other specified metals according to temperature, corrosion and structural requirements.

Final material compatibility should be confirmed according to gas composition, moisture, temperature, pressure or vacuum, gas velocity, dust loading, abrasion and required service life.

Movement Capability

The flexible element can be designed to accommodate axial compression, axial extension, lateral movement, angular deflection and selected combinations of these movements.

Actual allowable movement depends on joint dimensions, flexible-element profile, installed length, material construction, operating temperature and required cycle life.

Suitable Service

This product is mainly intended for flue gas, air, hot gas and industrial process-gas ducting operating at relatively low pressure. Negative-pressure, corrosive wet-gas, high-temperature and particle-laden applications require project-specific material and structural evaluation.

It should not be selected as a conventional pressurized liquid-pipeline joint, and rubber-joint pressure classes or water-pressure testing assumptions should not be applied without engineering confirmation.

Typical Applications

• Power-plant boiler and flue-gas ducting
• Flue-gas desulfurization and treatment systems
• Industrial fan inlet and outlet connections
• Dust-collection and particle-laden gas systems
• Cement, steel, metallurgical and chemical ducting
• Gas-turbine and industrial exhaust systems
• Ventilation, hot-air and air-recirculation systems

Installation Guidelines

• Confirm gas-flow direction, product orientation and liner overlap
• Verify duct dimensions, installed length and preset movement
• Keep connection frames aligned and avoid twisting the flexible element
• Do not stretch or compress the joint to correct duct misalignment
• Protect the flexible section from welding sparks and sharp objects
• Do not use the joint to support ductwork, equipment or insulation weight
• Provide sufficient clearance for the designed movement
• Inspect the flexible element, frame, liner and connections before operation

Operation and Maintenance

The flexible surface, metal frames, clamping components, internal liner and adjacent supports should be inspected periodically. Inspection intervals should reflect temperature, corrosion, vacuum, dust loading and vibration conditions.

Abnormal bulging, cracking, abrasion, leakage, excessive extension or localized overheating should prompt a review of the actual movement, gas flow, liner condition and support arrangement.

Information Required for Quotation

Please provide the following information so that the flexible construction and connection arrangement can be properly evaluated:

• Round diameter or rectangular duct dimensions
• Installed length and available installation space
• Operating, maximum and ambient temperatures
• Operating pressure, vacuum and pressure fluctuations
• Gas composition, corrosion and moisture conditions
• Gas velocity, dust loading and abrasion conditions
• Required axial, lateral, angular and combined movement
• Flange, frame, drilling or welded-connection requirements
• Flow-liner, insulation or accumulation-control requirements
• Installation position, quantity, packaging and destination port

We can review and customize integrally vulcanized non-metallic expansion joints according to operating conditions, duct dimensions, site sketches and project drawings. Final materials, dimensions, movement capacity and inspection requirements are subject to the approved technical specification and manufacturing drawing.