有許多大型容器的技术要求是在制造后或投入生产前,需进行真空負压試驗。这时,一般是用真空泵排除容器內的气体,以得到負压。但設备复杂、昂貴,且体积較大、操作不便。如用图示方法,則只需利用一台水泵,就可达到同样目的。 The technical requirements of many large vessels are that they require a vacuum negative pressure test after they are manufactured or before they are put into production. At this time, the vacuum pump is generally used to exclude the gas in the container to obtain negative pressure. But the equipment is complex, expensive, and bulky, inconvenient to operate. As with the pictorial method, just use a pump, you can achieve the same goal.