Non-metallic Lined Expansion Joint

Lined Non-Metallic Expansion Joint Overview

A lined non-metallic expansion joint is a flexible connection and movement compensation component designed for flue-gas, ventilation, dust-collection, desulfurization and selected corrosive process-gas systems.

The non-metallic flexible section accommodates axial, lateral and angular movement caused by thermal expansion, equipment vibration and installation misalignment. It can also help reduce mechanical loads and vibration transferred to connected ductwork and equipment.

An internal flow liner, metal sleeve or corrosion-resistant lining can be incorporated according to gas velocity, temperature, dust concentration, abrasion and corrosion conditions. The lining helps protect the flexible material from direct gas flow, particles and aggressive media.

Key Features

• Accommodates axial, lateral and angular movement
• Suitable for round, rectangular and custom duct connections
• Requires relatively short installation length
• Helps reduce vibration and structural noise transmission
• Internal liner helps protect the non-metallic flexible section
• Materials can be selected for heat, corrosion, abrasion and dust conditions
• Available with flanged, clamped, welded-frame or site-spliced construction

Construction

A lined non-metallic expansion joint generally consists of a metal frame, flexible fabric belt, sealing layer, reinforcement layer, insulation layer, clamping plates or fastening hardware, and an internal flow liner or lining.

The metal frame connects the expansion joint to the duct or equipment. The flexible section accommodates movement, the sealing layer limits gas leakage, the reinforcement layer improves dimensional stability, and the insulation layer reduces the temperature reaching the outer flexible materials.

The internal flow liner or lining can reduce direct impingement from high-velocity gas, dust and abrasive particles. Liner material, thickness, length and orientation should be selected according to flow direction, temperature, velocity and abrasion.

Flexible and Lining Materials

Flexible sections can be manufactured from glass-fibre fabrics, silicone-coated fabrics, fluoroelastomer-coated fabrics, PTFE composites, high-temperature textiles and other engineered flexible materials.

Internal liners or flow sleeves can be manufactured from carbon steel, stainless steel, corrosion-resistant alloys, fluoropolymer materials or other project-specified materials.

Final material selection should be based on medium composition, temperature, pressure, gas velocity, moisture, dust concentration, corrosion, abrasion and required service life.

Movement Capability

Lined non-metallic expansion joints can be designed to accommodate axial compression, axial extension, lateral movement and angular deflection. Selected fabric constructions can also accommodate combined movements.

Actual allowable movement depends on joint size, flexible-layer arrangement, installed length, operating temperature and required cycle life. The expansion joint should not support ductwork or equipment weight, and it is not a substitute for anchors, guides or load-bearing supports.

Typical Applications

• Boiler flue-gas and exhaust systems
• Flue-gas desulfurization and treatment equipment
• Industrial ventilation and hot-air ducting
• Dust-collection and particle-laden gas systems
• Chemical and selected corrosive process-gas ducts
• Power, steel, cement and metallurgical plants

Installation Guidelines

• Confirm gas-flow direction, product orientation and liner overlap direction
• Verify duct opening dimensions, installed length and preset movement
• Protect the flexible section from welding sparks and sharp objects
• Do not stretch or compress the joint to correct duct misalignment
• Align the metal frames and tighten clamping hardware evenly
• Do not use the joint to support ductwork, equipment or insulation weight
• Inspect the flexible belt, liner, connections and sealing areas before operation

Information Required for Selection

Please provide the following information so that the flexible section, lining and metal-frame 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 concentration and abrasion conditions
• Required axial, lateral and angular movement
• Flange dimensions, drilling or welded-frame requirements
• Flexible belt, insulation, flow-liner and lining requirements
• Quantity, packaging, installation location and destination port

We can design and manufacture lined non-metallic expansion joints according to operating conditions, duct dimensions, site sketches and project drawings. Final materials, dimensions, movement capacity, temperature range and inspection requirements are subject to the approved technical specification and manufacturing drawing.