Regarding the problem of inconsistent caliber between kitchen drain pipes and sink drain pipes.

1. The size of your measure is deviated from the engineering requirements, the diameter of the drainage pipe should be DN50 (50mm or 5 cm), the diameter of the sewer pipe of the sink should be DN32, and the pipe material should be considered if it is effectively connected, the material of the drainage pipe of your house should be cast iron pipe, and the sewer pipe of the sink is mostly PVC pipe, and it is difficult to seamlessly connect the two.

2. The vast majority of the current kitchen drainage is not seamless, as long as the sewer pipe of the sink is inserted into the drain pipe for more than 20 cm, and there is no elbow in the sink sewer nozzle of the insertion section, it will not cause overflow.

3. Therefore, a more reasonable method is to insert the sewer pipe of the sink into the drainage pipe, seal the gap between the two pipes with styrofoam or filler, and then seal it with silicone (glass glue) on the mouth.

If you want to dock, you can go to the building materials store and buy a PVC size head 50 40 or 50 32, but this kind of infrequently used accessories are more difficult to buy in small building materials.

Depending on the size of your grapes and the thickness of the sewer pipe, don't worry, even if it is blocked, it will be fine in a day or two, and this situation will rot quickly.

It's okay to put the small tube in the big tube, don't worry.