PP Ducting

PP ductwork is a plastic pipe made by extrusion molding of polypropylene (PP) resin. Its core value lies in leveraging the inherent excellent chemical resistance of PP material to address the issues of traditional metal ducts (such as galvanized iron sheets, stainless steel) being prone to rust, perforation, and having a short lifespan in corrosive environments.

PP pipe can withstand corrosion from the majority of acids, alkalis, and organic solvents (such asSodium hydroxideSulfuric acid,Nitric Acid、Sodium Hydroxide(Alcohol, etc.), with a lifespan significantly longer than metal pipes, and is particularly suitable for environments such as chemical processing, electroplating, and laboratories. The density of PP material is much lower than that of metal, making PP ductwork extremely lightweight. This results in easier transport, handling, and installation, effectively reducing installation costs and labor intensity. The inner surface is smooth with minimal friction resistance. The inner surface of PP pipes is extremely smooth, which prevents dust adhesion and reduces fluid resistance. This means that with the same power of the fan, a larger air exhaust volume can be achieved, or a smaller fan power is required to achieve the same air volume, leading to greater energy savings.

PP material is easily connected by hot melt welding, offering high strength at the weld joints, excellent sealing, and almost seamless appearance. Specialized flanges are also available for connection. In case of local damage, repair and replacement are extremely convenient.

III. Main Types

According to structure and application, PP ducts are mainly categorized into:

PP Round Duct (Straight Pipe):

The most common form is the circular cross-section, with specifications ranging from dozens to thousands of millimeters. It offers excellent aerodynamic performance and is the most frequently used type.

PP Rectangular Ducting

When installation space height is limited, rectangular ducts are used, which can make more effective use of the space.

PP Reducer/Reducing Coupling

Used for connecting ventilation pipes of different diameters.

PP Elbow/Bend Pipe

Used to change the direction of ventilation ducts, commonly available in 90° and 45° elbows.

PP Tee/Four-way Tee

Fork or manifold for ventilation ducts.

PP Air Valve: Used for adjusting the air volume in ventilation systems.

Four: Connection Method

Hot Melt Welding (most commonly used):

Utilize specialized PP welding torch and rods to heat and melt the pipe material and fittings together. The connection boasts high strength and excellent sealing, nearly becoming a single entity.

Flange Connection:

Welded PP flange at the pipe end, then secured together with bolts, with a sealing washer in between. Easy for disassembly and maintenance.

Socket and Spigot connection

For small-diameter pipes, socket-and-spigot joints may be used (with PP-specific adhesive).

In summary, PP ductwork is the "expert" for tackling the challenges of corrosive gas transmission. It excels in medium and low-temperature, highly corrosive conditions, and has become the standard ventilation material for industries like chemicals and laboratories, thanks to its lightweight, corrosion-resistant, and energy-saving properties. However, when selecting it, one must pay close attention to its temperature limits and outdoor aging resistance issues.