1. Composite smoke pipe

Composite smoke pipe, also known as fireproof composite smoke exhaust duct, is mainly composed of two layers of metal thin plates inside and outside and a middle insulation material layer.

Material:
Inner thin plate: usually galvanized plate or stainless steel plate, these materials have excellent corrosion resistance and high temperature resistance.
Outer thin plate: mostly aluminum-zinc-magnesium alloy plate or color steel plate, these materials have good corrosion resistance and aesthetics.
Intermediate insulation material: can be glass wool, aluminum silicate plate or rock wool, etc., these materials have excellent thermal insulation and fireproof properties.
Features:
Good fireproof performance: The fireproof grade of the composite smoke pipe generally reaches A2 level, and it can withstand high-temperature smoke.
Low thermal conductivity: The presence of the middle insulation material makes the composite smoke pipe have a lower thermal conductivity, avoiding the problem of excessive indoor and outdoor temperature gradient.
Good corrosion resistance: The material selection of the inner and outer two layers of metal thin plates makes the composite smoke pipe have good corrosion resistance.
Various connection methods: flange connection, bayonet connection, metal hose connection, etc. can be used for connection, which has greater flexibility.
Wide range of applications: suitable for smoke exhaust, ventilation and air supply systems.

2. Welded pipe

Welded pipe is a steel pipe made by welding steel plates or strips after curling and forming.

Classification:
According to the production method: it can be divided into arc welded pipes, resistance welded pipes, (high frequency, low frequency) gas welded pipes, furnace welded pipes, etc. Smaller diameter welded pipes use straight seam welding, while large diameter welded pipes mostly use spiral welding.
According to the shape of the steel pipe: it can be divided into round welded pipes and special-shaped (square, rectangular, etc.) welded pipes.
According to the material and use: it can be divided into welded steel pipes for fluid transportation in mines, galvanized welded steel pipes for low-pressure fluid transportation, and electric welded steel pipes for belt conveyor rollers.
Features:
Strength: Although the strength of welded steel pipes is lower than that of seamless steel pipes, they are still widely used.
Delivery length: Generally, welded pipes are used to transport low-pressure fluids. The delivery length is usually 4~10m, and fixed length (or multiple length) is often required for delivery.
Wall thickness: According to the specified wall thickness, welded pipes are divided into ordinary steel pipes and thickened steel pipes. Steel pipes are divided into threaded and non-threaded types according to the form of pipe ends.
Application range:
Widely used in tap water projects, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction and other fields.
According to function, it can be divided into liquid transportation (water supply, drainage), gas transportation (gas, steam, liquefied petroleum gas), and structural use (pile pipes, bridges, docks, roads, and building structure pipes).

3. Conjugate pipe (taking HDPE conjugate pipe as an example)

HDPE (High Density Polyethylene) is a high-density polyethylene with excellent chemical corrosion resistance, high strength and stiffness, good wear resistance and low water absorption. HDPE conjugate pipe is a pipe made of HDPE material.

Features:
Chemical corrosion resistance: It can resist the corrosion of various acids, alkalis, salt solutions and various chemical substances, and can operate stably in various harsh environments.
High strength and rigidity: It can withstand greater pressure and heavy loads, and is not easy to deform or break.
Abrasion resistance: It can resist the impact and wear of particles, reducing the frequency of pipeline maintenance and replacement.
Low water absorption: It is not easy to be affected by moisture, and can still maintain good performance in a humid environment.
Good welding performance: Pipeline connection can be carried out by hot melt connection and other methods, with high connection strength, ensuring the sealing and reliability of the pipeline system.
Application range:
Commonly used in water supply, drainage, natural gas transportation and industrial fluid transportation.
It is also widely used in underground drainage systems, because HDPE conjugate pipes have low water absorption and good chemical corrosion resistance, which are suitable for use in humid underground environments that are easily corroded by chemical substances.
In short, composite smoke pipes, welded pipes and conjugate pipes have their own characteristics and are widely used in different fields. Which pipe material to choose depends on the specific application scenario and needs.