Metallic expansion joints are significantly different from non-metallic expansion joints in design, material, performance and application. Here are some of the main differences:
Materials
Metal expansion joint: Usually made of stainless steel, carbon steel or other alloys with high strength and pressure resistance.
Non-metallic expansion joint: Constructed of non-metallic materials, such as fiber fabric, rubber, silicone, fluoroplastics (such as PTFE), etc. These materials have good flexibility and corrosion resistance.
Structure
Metal expansion joint: May contain metal components such as bellows, hinges, tie rods, etc., forming a corrugated structure to achieve expansion, contraction and bending.
Non-metallic expansion joint: Usually includes non-metallic skin, insulation layer, deflector, bracket, etc. The structure is relatively soft and can absorb large lateral displacement.
Performance
Compensation ability: Non-metallic expansion joints generally have greater compensation capacity under the same form factor, especially in lateral displacement.
Resistance: Metallic expansion joints generate greater reaction forces (resistance) after being stressed than non-metallic expansion joints, which may lead to additional stress on the connecting equipment.
Temperature and corrosion resistance: Non-metallic expansion joints can have good high temperature and corrosion resistance under specific material selection, whereas metallic expansion joints depend on the properties of the selected metal.
Application
Metal expansion joint: Suitable for high pressure, high temperature and application scenarios that require high intensity, such as chemical industry, oil, natural gas, power industry.
Non-metallic expansion joint: It is more suitable for environments with corrosive media, sound and shock absorption, and special requirements for temperature and chemical stability, such as ventilation system, dust removal system, flue gas treatment, etc.
Economy
Cost: The initial cost of non-metallic expansion joints may be lower, but complex design non-metallic expansion joints may also be more expensive. The material costs and manufacturing costs of metal expansion joints are generally higher.
Installation and maintenance
Non-metallic expansion joint: Lighter weight and easy to install, but may require more frequent inspection and replacement in harsh environments.
Metal expansion joint: While the installation may be heavier, it may have a longer service life and lower maintenance requirements due to the sturdy material.
When choosing a metal expansion joint or a non-metal expansion joint, you need to consider the operating conditions of the specific application, including pressure, temperature, media properties, space constraints, and budget, to ensure that you choose the most suitable solution.