XICHENG EP LTD. specializes in the production of PP air ducts, also known as polypropylene plastic air ducts and plastic ventilation ducts. PP air ducts are usually used for the exhaust of corrosive waste gas in the environment of industrial plants, the exhaust of gas in the fume hood in the laboratory, and the exhaust of VOC organic waste gas. The advantages of PP air ducts are light weight, acid and alkali corrosion resistance, PP welding rods are used for hot-melt welding, elbows, flanges, tees, variable diameters and other supporting pipe fittings are easy to process and install. It is currently the most widely used in waste gas treatment in the environmental protection industry A kind of ventilation duct.

Working principle of PP duct

PP air ducts are used in industrial exhaust such as acid, alkali, organic waste gas, etc. By installing induced draft fans at the end, the polluted waste gas in the environment is drawn through the PP anti-corrosion fan to be discharged outdoors. PP air ducts are usually divided into positive pressure air supply or negative pressure ventilation working modes, with smooth inner wall and low resistance.

PP duct performance characteristics

1. No corrosion: PP air duct can withstand the PH value in a wide temperature range, ranging from 1 to 14 high concentrations of acid and alkali corrosion.

2. Wear resistance and non-scaling: The inner wall of the PP duct and pipe fittings is uniform and smooth, with low flow resistance and no scaling.

3. Reduce vibration and noise: PP air duct has excellent sound insulation performance, which can significantly reduce vibration and noise caused by liquid flow.

4. Anti-freeze cracking: The material used in the PP duct is excellent in elasticity, so that the pipe and pipe section can expand with the frost heaving liquid without bursting and cracking.

5. Anti-condensation, low heat loss: The material used in the PP duct is a poor thermal conductor, which can reduce condensation and reduce heat loss.

6. Simple installation: PP air duct is light in weight, easy to install and operate, and has weldability.

7. Long service life: The PP duct has a service life of up to 50 years under the specified temperature, pressure, medium and other use conditions.

8. Excellent corrosion resistance: It is resistant to corrosion of most chemicals, and can withstand the corrosion of high-concentration acids and alkalis with a pH value of 1-14 in a wide range.

9. Good hygiene performance: PP air duct material has only carbon and hydrogen elements in its molecular structure, which is non-toxic and tasteless, and has reliable hygiene performance.

10. Heat-resistant, heat-preserving and energy-saving: The maximum operating temperature of PP duct is about 70 degrees, and the thermal conductivity of this product is only 1200 of that of steel pipe, so it has better heat preservation performance.

PP duct system structure

In order to form a complete PP anticorrosive piping system, in addition to PP air ducts, it is not enough, but also PP air duct fittings, which can be installed together to form a complete anticorrosive acid and alkali resistant exhaust piping system.

• PP elbow

• PP tee

• PP reducer

• PP flange

• PP casing

• PP damper

We collectively refer to the above products as PP duct exhaust system

PP duct specifications

There are two types of PP ducts from the shape, one is square PP ducts, and the other is round PP ducts. From the application point of view, the amount of circular PP duct is relatively large. The circular PP duct is easy to make. The PP sheet can be rolled into a circular tube by a plate rolling machine. The labor and mechanical costs are relatively low, while the square PP duct is made of PP sheet. The hot-melt bending machine is made by bending 90 degrees four times and then welded by a butt welding machine. There are many processes. Compared with square pipes with the same circumference or cross-section, the price of square pipes is higher. Of course, it depends on PP. The wall thickness of the duct and whether to strengthen the outer flange.

How to select PP duct

How to select the PP air duct needs to be determined according to the application requirements. If it is used for exhaust gas exhaust, calculate the total air volume, unit: cubic meter/hour. Design the flow velocity of the gas in the PP duct, unit: m/s, divide the air flow by the flow velocity and wait until the cross-sectional area of the PP duct, after opening the root, multiply it by 2 to get the diameter of the pipe.

PP duct installation method

• PP air pipe socket connection, that is, a PP sleeve is welded at the end of each section of air pipe to facilitate the insertion of the next section of air pipe;

• PP air pipe and air pipe flange type connection, that is, a PP flange is welded at both ends of each section of air pipe, and the screw-to-lock connection is adopted during installation.

• PP duct reinforcement method. In industrial exhaust, the end centrifugal fan is used for exhaust in most cases. Negative pressure is formed in the PP duct. The industry design specification stipulates the wall thickness of the PP duct at a certain wind speed. And the strengthening method, usually the PP duct is reinforced by the outer flange, such as a 3-meter-long duct with 2 flanges, which is beautiful and durable. While the large square air duct is reinforced by the outer flange, the inner part is supported by the PP circular pipe.