实验室用加热法制备气体,在操作时稍有不当就会造成水槽中的水回流,致使实验失败或仪器损坏。欲解决这个问题,最简单、而又不需花一分钱的办法,是在通入水槽的导气管连接处或末端装上防回流阀。见图1。方法如下:1.找一根废玻璃管,可根据需要做成图2中任一种式样。圆锥部分要拉制的光滑而均匀。2.用废橡皮塞做一个略小于玻管内径的非常光滑的圆台,将其放入拉制好的玻管中。再在玻管的另一端烧上两个防止圆台脱落的凹点。见图2。这样一只简易的防回流阀便 The laboratory uses heating to prepare gas, and if it is operated improperly, it will cause the water in the water tank to flow back, causing the experiment to fail or the instrument to be damaged. To solve this problem, the easiest way without spending a penny is to install a backflow prevention valve at the end of the gas pipe connected to the water tank or at the end. see picture 1. The method is as follows: 1. To find a waste glass tube, according to the need to make any of the patterns in Figure 2. The cone part should be smooth and uniform. 2. Use a waste rubber plug to make a very smooth round table that is slightly smaller than the inner diameter of the glass tube and place it in a drawn glass tube. Burn the two pits on the other end of the glass tube to prevent it from falling off. See Figure 2. Such a simple backflow prevention valve