高层建筑底层厕所大便器存水弯返水,轻者废气遗出,重者水漫厕所,影响室内卫生,对人体健康不利。返水的主要原因是:上、下(中)层厕所同时排水而且排水量较大,见图1,立管内形成上、下水塞。在流动过程中,下水塞首先流入排水横管,流速减慢。上水塞在立管内仍以匀加速运动下落。两水塞之间空气受到压缩。当被压缩气体压强大 Toilet traps in high-rise buildings are trapped at the bottom of the toilet, light emissions are emitted, and toilets are filled with water, affecting indoor hygiene and adverse to human health. The main reason for returning water is that the upper and lower (middle) toilets drain at the same time and have a relatively large displacement. See Figure 1. The upper and lower toilets are formed inside the riser. During the flow, the drain plug first flows into the drain cross pipe, and the flow rate slows down. The upper water plug still falls in a uniform acceleration motion in the riser. The air between the two water plugs is compressed. When compressed gas pressure is strong