In the design of PVC drainage system, the tee is a key accessory connecting the main pipe and the branch pipe, and its selection directly affects the drainage efficiency, system stability and use experience. When many people face the positive tee, oblique tee and reducer tee, they often choose the wrong accessories because they are not clear about their respective application scenarios, resulting in problems such as water flow blockage, noise or poor drainage in the later stage. Today, we will analyze the application scenarios and selection logic of these three common tee one by one.

positive tee, as the name implies, is a tee with three interfaces vertically crossed (usually the main pipe and the branch pipe are at a right angle of 90 degrees). Its structure is simple, and it only needs to connect the branch pipe with the main pipe vertically during installation. It is the most common type of tee. The applicable scenario mainly focuses on the situation where the main pipe and the branch pipe need to be connected vertically: for example, the connection between the toilet drain branch pipe (usually 110mm) and the riser pipe in the toilet - the toilet drain needs to be drained in a straight line, and the vertical structure of the positive tee can ensure that the water flow quickly enters the main pipe; for example, the drain branch pipe (75mm) of the kitchen sink is connected to the main riser. At this time, the position of the sink is usually on the side of the riser, and the vertical connection is more space-saving. However, the disadvantage of the positive tee is that the water flow has a large impact. If it is used for the branch pipe of high-rise drainage, it may generate certain noise, so it is more suitable for low-rise or areas with slower water flow speed.

The three interfaces of the oblique tee are at a certain angle (usually 45 degrees or 60 The core of its design is to guide the smooth transition of water flow and reduce the impact and noise caused by right-angle turns. Applicable scenarios are mostly situations where the water flow path needs to be optimized: for example, the drainage riser branch of high-rise residential buildings - the high-rise water flow speed is fast, and the angle of the oblique tee allows the branch pipe water to flow in the direction of the riser water flow, avoiding the direct collision of the two streams and reducing the risk of blockage; another example is the balcony drainage system. The branch pipe of the balcony floor drain usually needs to be connected to the riser from the side. The oblique tee can make the water flow smoother, especially suitable for the water flow containing sundries such as the drainage of the balcony washing machine. There are also drainage branches in the bathroom shower area. If the shower area is far from the riser, the oblique tee can reduce the number of pipe turns and improve the drainage In addition, the oblique tee is also commonly used in the renovation of the drainage system of old buildings, which can effectively solve the noise problem caused by the original positive tee.

reducer tee is characterized by the different diameters of the three interfaces (such as the main pipe 110mm, the branch pipe 75mm or 50mm), which is mainly used for connection scenarios where the diameter of the main pipe and the branch pipe does not match. In the actual drainage system, the main riser usually uses a larger diameter (such as 110mm) to ensure the total displacement, while the branch pipe (such as washbasin, wash basin, floor drain) uses a smaller diameter (such as 75mm or 50mm). At this point, the reducer tee becomes a necessary choice: for example, the 75mm drainage branch pipe of the bathroom washbasin is connected to the 110mm main riser, and the reducer tee can accurately match the two calibers to avoid water flow blockage caused by inconsistent calibers; for example, the basement drainage system of a villa or duplex building, the main pipe may be 160mm caliber, while the branch sewage basin or mop pool is 110mm caliber, and the reducer tee can achieve seamless connection; there are also commercial places such as the kitchen drainage of a restaurant, the main pipe needs to deal with a large amount of wastewater, and the branch vegetable sink uses a small diameter. The reducer tee can ensure the balance of water flow between the main and branch pipes. It should be noted that the selection of the reducer tee should strictly match the caliber of the main and branch pipes to avoid water flow backflow caused by "large pipe connected to small pipe", or water flow sedimentation caused by "small pipe connected to large pipe".

In summary, the selection of PVC drain tee needs to be closely linked to three cores: pipeline direction (vertical or inclined), water flow demand (whether it needs to reduce impact), and diameter matching (whether the main branch pipe is the same diameter). The positive tee is suitable for scenes with vertical connection and smooth water flow; the oblique tee is suitable for scenes where water flow needs to be optimized and noise reduced; the reducer tee is specially designed to solve the problem of caliber mismatch. Choosing the right tee can not only improve the stability of the drainage system, but also avoid the trouble of later maintenance - after all, the details of the "invisible engineering" of the drainage system are the key.