Metal Corrugated Expansion Joints in Cement Industry

Product Introduction

I. Product definition and function

Metal corrugated expansion joint is a kind of flexible element that compensates the displacement of pipe due to temperature change, mechanical vibration or foundation settlement through elastic deformation of corrugated pipe. In the cement industry, its core functions include:

1. Compensated thermal displacement: Absorb the difference in axial, transverse or angular thermal expansion of cement production equipment (such as preheater, kiln, waste heat boiler) due to high temperature, and reduce the stress of pipeline system.

2. Shock and noise reduction: Isolate the transmission of equipment vibration to pipeline, reduce noise, and protect the stability of pipeline connection.

3. Adapt to complex working conditions: Solve the problem of pipeline deformation in the environment of high dust, high temperature (up to 800-1300℃) and strong gas corrosion in cement plant.

II. Structure and materials

1. Core Components：

• Bellows: Made of stainless steel (e.g. 304, 316L) or superalloy (e.g. Inconel), manufactured by hydroforming process, with high flexibility and fatigue resistance.

• guide tube: Lined with wear-resistant materials (such as ceramic fiber or silicon carbide) to prevent dusty airflow from directly washing the bellows and prolong the service life.

• End tube and flange: Carbon steel or low alloy steel, used to connect piping systems.

• Limit devices such as pull rods and hinge plates control the compensation direction and prevent excessive displacement.

III. Main types and selection

According to the specific working conditions of cement plants, the commonly used types include:

1. Axial type: It is suitable for axial expansion and contraction compensation of straight pipes, such as kiln tail flue gas pipes.

2. Large tie rod transverse type: Compensate for lateral displacement, used for large air ducts or equipment interfaces.

3. High temperature special type: Using multi-layer corrugated structure + high temperature resistant coating, it is applied to high temperature areas such as kiln head and grate cooler.

4. Rectangular nonmetallic composite type: Combined with metal frame and non-metal skin, suitable for compensation of large dust content and low pressure occasions.

IV. Technical parameters and advantages

1. Performance Indicators：

• Pressure range: 0.1-6.0 MPa

• Temperature range: -50℃ ~1300℃

• Compensation amount: up to ±200mm in axial direction and ±100mm in transverse direction.

• Long-life design: The fatigue life of bellows is ≥5000 times, and it can reach 10,000 times under special working conditions.

• Compact structure: Reduce the demand for installation space and adapt to the dense pipeline layout of cement plant.

• Maintenance-free: There is no leakage link, only the bellows wear and structural parts deformation need to be checked regularly.

Typical Application Scenarios

1. Kiln tail preheater system: Compensate the thermal expansion difference between the rotary kiln and the preheater, and prevent pipeline cracking.

2. Waste heat generation pipeline: Balance the thermal displacement of the pipe connecting the boiler to the steam turbine.

3. Air duct of dust removal system: Absorb the deformation caused by fan vibration and fluctuation of flue gas temperature.

4. Cement delivery pipeline: Adapt to mechanical vibration and foundation settlement during material conveying.

VI. Key Points of Selection and Installation

1. Selection basis: The medium temperature, pressure, dust concentration, compensation amount and installation space limitation should be comprehensively considered.

2. Installation Specifications：

• Matching guide bracket to prevent the pipe from damaging the bellows by lateral force.

• Pre-stretch or pre-compression treatment, adjust the initial state according to the ambient temperature.

INDUSTRY STANDARDS AND

The product complies with GB/T 12777 standard, and some high-end models are designed with reference to the US EJMA standard, and have passed the safety registration of pressure pipe elements (e.g. TS certification).