In a home renovation or building drainage system, the PVC drain pipe elbow is an inconspicuous but crucial accessory - it is responsible for changing the direction of water flow and connecting pipes in different directions. But if the size of the elbow does not match the pipe, it can cause leakage at the interface, affect the drainage efficiency, and even cause pipe blockage. Today we will focus on the most commonly used 90-degree and 45-degree PVC drain pipe elbows, and talk about their specifications, suitable pipes and selection points.

Let's talk about the 90-degree PVC drain pipe elbow first. As the core accessory of the "sharp turn" in the drainage system, it is often used in the scene of vertical pipe to horizontal pipe, such as the corner where the toilet sink drain pipe is connected to the main drain pipe, and the location where the kitchen sink drain pipe is connected to the riser pipe. At present, the specifications of 90-degree elbows on the market are divided by nominal diameter (DN). Common ones are DN50 (corresponding to the outer diameter of the pipe about 50mm), DN75 (about 75mm), DN110 (about 110mm), DN160 (about 160mm) - DN50 is mostly used for drainage of basins and washing machines. DN110 is a common size for residential main drainage pipes.

Regarding the suitable pipe, the nominal diameter of the 90-degree elbow must be exactly the same as the pipe: for example, the elbow of DN50 can only be connected to the PVC drain pipe of DN50, and the elbow of DN110 corresponds to the pipe of DN110. Also pay attention to the matching of wall thickness - if the pipe is S2.5 grade (such as DN110 pipe wall thickness 2.0mm), the elbow must also choose the same grade wall thickness, otherwise it is easy to break or leak due to uneven strength when connecting.

Look at the 45-degree PVC drain pipe elbow again. Its function is "slow steering", which is more conducive to reducing water flow resistance than the 90-degree elbow. It is suitable for small-angle steering scenarios of long-distance drainage pipes, such as the corner of the outer wall of the balcony rain pipe and the gradual change of the basement drain pipe. The specifications of the 45-degree elbow are basically the same as those of the 90-degree, covering DN50 to DN160 and other sizes, but the application scenario focuses more on "low-resistance drainage" - such as the steering of rain risers in high-rise residences, and the 45-degree elbow can avoid noise or pipe wear caused by excessive water flow impact.

adapts to the same principle as the 90-degree elbow: the size is the same as DN and the wall thickness is the same grade. For example, the 45-degree elbow of DN75 must be matched with DN75 PVC pipe, and the wall thickness of both must be S3.2 (such as the wall thickness of 2.3mm) to ensure a tight connection.

Finally, I will give you a few selection tips: 1. Before buying an elbow, look at the logo on the pipe (such as "PVC-U drain pipe DN110 S2.5"), and choose the elbow with the same parameters according to the logo; 2. You can bring a section of pipe samples to compare, and insert it into the elbow interface to try to tighten it - it can be inserted and there is no obvious gap is a match; 3. Try to choose products from well-known manufacturers (but not to mention specific brands) to avoid inferior elbows due to size deviation.

In fact, the size selection of PVC drain pipe elbows is not so complicated. The core is one sentence: the DN value and wall thickness of the elbow and the pipe are exactly the same. As long as you grasp these two points, you can avoid 90% of installation problems and make the drainage system more worry-free.