PP Flame Retardant Processed T-Connector

Product Model	PPs plate welded branch tee
Category	PP Machined Products
Reference Price	Price on request

Hot Customizable for Working Conditions 11 Technical Parameters

Product Overview

The PP flame-retardant processing tee is a three-way connection component used in ventilation ducts when a branch pipe needs to be taken off from the main pipe. It is named for its three-directional interfaces. The tee can be made by cutting and welding PP flame-retardant plates or by processing formed parts. The three interfaces connect the inflow end, outflow end, and branch pipe of the main pipe, serving as a key component in the exhaust system for air flow diversion and convergence.

Tees are classified into equal-diameter and reducing types: equal-diameter tees have three interfaces of the same diameter, used for branching in pipes of the same diameter; reducing tees have the same main pipe diameter but a smaller branch pipe diameter, commonly used for diverting small branch pipes from large main pipes, which is the most common form in exhaust systems. Based on the branch pipe angle, they are further divided into straight tees and inclined tees. Inclined tees have the branch pipe angled along the airflow direction, resulting in lower resistance compared to the right-angle straight tees. Xicheng Environmental can process large specifications and various non-standard angles and diameters of flame-retardant tees.

The PP material makes the tee resistant to acid, alkali, and salt corrosion, self-extinguishing when exposed to fire, with welds and base material of the same material, ensuring continuous anti-corrosion and fireproofing at the branching position. Circular and rectangular systems are matched with round and square tees, respectively. Rectangular tees are formed by bending and welding plates, while circular tees can be welded from plates or assembled from formed parts.

Working Principle

Tees achieve pipe diversion and convergence. In an exhaust system, branch pipe airflow enters through a lateral interface and merges with the main pipe airflow to flow downstream together; in supply or distribution systems, the opposite occurs, with a portion of the main pipe airflow diverting into the branch pipe at the tee. Reducing tees maintain branch pipe velocity by reducing the branch pipe diameter, while inclined tees allow the branch pipe to enter at a sharp angle along the main pipe airflow direction, reducing the impact and eddies when the two airflow streams meet.

Tees are areas where local resistance and wear are more concentrated in pipelines. When airflow diverts or converges, the abrupt change in direction causes pressure loss, and dusty airflow can scour the diversion area. The smooth, corrosion-resistant, and wear-resistant surface of the PP material, combined with a reasonable inclined angle and transition radius, can reduce resistance and scouring. PP flame-retardant plates and matching welding electrodes ensure long-term use of the tee in corrosive gas and fireproofing environments, with continuous and sealed welds preventing air leakage at the branch point.

Structural Composition

Circular reducing tees consist of a main pipe shell and a branch pipe interface. The main pipe is a straight circular tube with an opening on the side for welding the branch pipe connection, with transition reinforcement added at the angle between the branch pipe and the main pipe, and flanges or sockets welded at the three ends. Inclined tees have the branch pipe inclined along the airflow direction, with the intersection line unfolded for smooth welding. Rectangular tees are formed by bending and welding plates into a main pipe and a branch pipe box, with optional internal flow guides.

Equal-diameter tees have three interfaces of the same size, while reducing tees have a smaller branch pipe interface that transitions through conical or inclined connections. Tee end connections include flanges, socket welding, and often include air valve interfaces on the branch pipe. Large-specification tees have reinforced plates or ribs welded to the outer wall and at the branch intersection points to withstand the weight of the branch pipe and airflow forces, with independent supports installed under the branch pipe during installation.

Specification Model Table

The following table categorizes the types of tees and their applicable scenarios, with pipe diameters matching the main and branch pipes.

Category	Feature	Applicable
Equal-diameter tee	Three interfaces of the same diameter	Branching in same-diameter pipes
Reducing tee	Branch pipe diameter reduced	Diverting small branch pipes from large main pipes
Inclined tee	Sharp angle inclination	Reducing resistance

Product Features

The PP flame-retardant processing tee is available in a full range of forms and can be produced in large specifications, serving as the core component for corrosion-resistant air duct branching and convergence. Key features include:

PP flame-retardant plates welded, resistant to acid, alkali, and self-extinguishing
Multiple forms available: equal-diameter, reducing, straight, and inclined
Inclined tees align with airflow to reduce convergence resistance
Customizable for large specifications and non-standard angles and diameters
Reinforced welding at intersection points for robust structure
Matching round and square tees for respective systems
Flange and socket connections for easy integration with pipelines

Material	PPs Flame Retardant Panels
Processing Technology	Plate Welding / Forming Combination
Interface Type	Equal Diameter / Variable Diameter
Branch angle	!-- Butt Splice / Angled Splice --
Connection Method	Flange / Butt-welding
Flame Retardant Properties	Self-extinguishing
Corrosion resistance performance	Acid and Alkali Salt Resistance
Applicable Section	Round / Rectangular
Specifications and Features	Large-Scale Custom Non-Standard Manufacturing
Strengthening Method	Welded reinforcement at the junction
Flow Diversion Options	With guide flow structure

Application Industries

Junction points where branch ducts serving individual workshops are taken off the main exhaust duct
Points where exhaust hoods over multiple tanks on electroplating lines merge into the main duct
Tees where exhaust from multiple laboratory fume hoods converges
Fittings for flow diversion and combining in waste gas networks of chemical plant areas
Tees where exhaust risers in semiconductor plants connect at each floor level
Confluence points for odor collection from multiple zones at wastewater treatment stations
Branch tees with guide vanes for high-airflow rectangular ducts

Typical Process Locations

Tees are installed where the main duct branches off or converges. In exhaust systems, branch ducts from each exhaust collection point connect to the main duct through reducing mitred tees in the direction of airflow, converging stage by stage toward the purification equipment and fans. The position and angle at which branch ducts join the main duct affect resistance balance; in design, branch ducts should be mitred into the main duct from the side or above at an acute angle, avoiding direct head-on impingement. The tee branch is usually followed immediately by a manual damper for easy adjustment of airflow in each branch.

During installation, the tee main section must be aligned coaxially with the duct, the branch direction must conform to the drawings, intersection welds must be continuously sealed, and flange gaskets must be intact. The weight of the tee and branch ducts should be carried by hangers and supports; in particular, for large-diameter branch ducts, the tee welds must not bear the cantilever weight of the branch over the long term. Mitred tees are directional: during installation, the inclined direction must follow the main duct airflow, and reversed installation will increase resistance. Before installing a tee, verify the main and branch diameters, angles, and flange standards; the branch of a mitred tee should face in the direction of the main duct airflow, with intersection welds continuous and full and leak testing performed; the weight of branch ducts and dampers should be carried by hangers and supports so that the tee welds do not bear cantilever loads over the long term; the joint should be temporarily reinforced during hoisting; during operation, focus inspections on the intersection line welds and flange seals, and shut down for repair welding if leakage or deformation is found.

The straight tee connects the branch pipe and the main pipe at a right angle, featuring simple processing and minimal space occupation. However, the direct intersection of airflow at right angles results in significant local resistance, making it suitable for areas with low branch pipe airflow, low wind speed, or limited space. The inclined tee joins the branch pipe to the main pipe at an acute angle along the airflow direction, ensuring smooth airflow convergence, low resistance, and low noise. It is preferred for high-flow branch pipes and systems with strict energy-saving and noise reduction requirements. When conditions permit, the branching and merging of exhaust main pipes should ideally use inclined tees to allow airflow to merge smoothly along the main pipe direction. In cases of budget constraints or limited space, small-flow branch pipes can use straight tees, but airflow dampers should be installed to balance resistance. Selection should consider the airflow ratio between the branch pipe and the main pipe, the included angle, and installation space, with particular attention to the impact of tee type on total resistance in high-flow, long-distance transportation systems.

Three interfaces with the same size are equal-diameter tees, used for branching or merging of pipelines with the same diameter; when the main pipe diameter remains unchanged and the branch pipe diameter decreases, it is a reducing tee, used for diverting small branch pipes from a large main pipe. In ventilation systems, the airflow at each collection point is typically much smaller than the main pipe airflow, and the branch pipe diameter is also smaller, so the vast majority of branching uses reducing tees. Reducing tees maintain stable main pipe velocity while ensuring the branch pipe velocity meets gas transport requirements, making them a frequently used form in engineering. Equal-diameter tees are mostly used for splitting pipelines with the same diameter between main pipes, or for connecting equipment interfaces with the same diameter. When selecting, judge based on the actual diameters of the three interfaces. The reduction transition of the branch pipe should be smooth to avoid additional resistance caused by sudden reduction; if necessary, a reducing adapter should be installed separately after the tee.

High resistance in tees should first prioritize the use of inclined tees, allowing branch pipes to connect along the main pipe airflow direction while controlling the angle between the branch pipe and the main pipe to avoid excessive angles, generally using acute-angle Bevel . Additionally, flow guides can be installed inside the tee to smoothly merge the two airflow streams, preventing the branch pipe's airflow from directly opposing the main pipe's incoming flow. Properly configure branch pipe dampers for airflow balance to prevent excessively high branch pipe velocities, entrainment, and backflow. The diameter reduction transition in reducing tees should be gradual to avoid sudden contractions. During installation, ensure the tee orientation is correct with the inclined end facing the airflow, smooth welding seams on the inner wall without weld ridges. These measures can significantly reduce the local resistance of the tee; if the system resistance remains high, consider appropriately increasing the main pipe or branch pipe diameter or reducing the internal pipe velocity.

Cannot be directly mixed, circular tee for circular pipe, rectangular tee for rectangular pipe, as their interface shapes and flange standards differ. Forcing them to connect will result in cross-section misalignment and air leakage. When converting between circular main pipes and rectangular branch pipes in the same system, use square-to-round adapters or directly create square-round transition sections at one of the tee's interfaces before connecting the corresponding cross-section pipe segments. When ordering, clearly specify the cross-sectional shape, dimensions, and flange standards for each of the three interfaces, indicating which one is square and which one is round to avoid incompatibility upon arrival. Square-round transition tees can be manufactured as a single piece by the supplier, resulting in smoother surfaces and lower resistance compared to on-site assembly. When arranging piping, minimize frequent square-round cross-section conversions. Ensure smooth transitions at conversion points to avoid abrupt expansions or contractions that increase resistance and noise.

Required, especially for large diameters and horizontal branches. The main function of the branch connection weld in a tee is to ensure sealing and diversion. It should not bear the cantilever weight of the branch or operational vibration for long periods. Horizontal branches should be equipped with support brackets near the tee, while vertical pipes should have fixed brackets to transfer the weight and thermal expansion stress of the branch to the brackets, preventing stress concentration at the tee weld that could lead to cracking. When heavy components such as valves and actuators are installed on branches, independent supports must be provided on both sides of the valves to prevent the weight from pressing on the tee and pipes. The type and spacing of support brackets should be determined based on the branch diameter, wall thickness, and medium, with denser arrangements required for large-diameter plastic pipes. The installation sequence should prioritize fixing brackets first, followed by welding and connection, to avoid misalignment and additional stress caused by welding in a suspended state. Regular inspections should be conducted after operation to check for deformation in the tee welds and brackets.

For custom-made tees, provide the main pipe diameter or rectangular cross-sectional dimensions, branch pipe diameter or cross-sectional dimensions, the angle and connection direction between the branch pipe and the main pipe, connection methods for all three interfaces, and flange standards. Additionally, specify the plate thickness and flame retardancy requirements. For eccentric tees, indicate whether the branch pipe connects in the direction of airflow or against it, left or right, upper or lower, and whether it includes a flow guide plate. Provide a pipe isometric drawing or mark flow direction on a plan view to clearly express angles and directions, avoiding processing orientation errors. For tees adjacent to equipment or dampers, also provide interface dimensions and flange standards for the adjacent components. Complete parameters and clear drawings enable the manufacturer to accurately perform cutting, determine intersection lines, and design flow guides, ensuring all three interfaces align smoothly upon arrival, reducing on-site modifications and rework.

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