A group of senior students from Zhejiang University have successfully developed an "air hand-washing device."

浙江大学的一队大四学生成功研制出了“空气洗手装置”。

The device utilizes¹ an infrared² ray induction³ system, which detects the presence of hands. A tap then sprays a light water mist along with a strong gust⁴ of air, which the students have proven to be nearly as effective as traditional hand-washing.

该装置利用了红外线感应系统，可以探测到双手的存在。之后，水龙头就会喷出雾状水滴和高速气流，学生们已经证实了此方法和传统的洗手方法一样有效。

However, the device uses only 10 percent of the water that regular hand-washing does.

但是，这种装置相比常规的洗手方法，只用10%的水量。

Li Qizhang, a member of the team that developed the device, told a reporter from thepaper.cn that a model of their device has already been installed in a classroom building at the university, and that the results have been satisfactory.

研发该装置的团队中一名名叫李启章的成员告诉《澎湃新闻》的记者，这个装置的模型在大学的教学楼里安装了一台，效果令人满意。

The students have set up a company to further promote their product.

学生们已经成立了一家公司来进一步推广他们的产品。

In 2014, a student named Chen Puyang first came up with the idea while washing his hands in the school cafeteria. Washing one's hands uses a lot of water, Chen thought. Would it be possible to replace the water with air?

2014年，陈濮阳同学在学校食堂洗手时首先想出了这个主意。他认为，洗手会浪费很多水，那么可以用空气来代替水吗？

Others may not have given the question a second thought. However, for Chen and Li, who were studying fluid mechanics, this constituted a brilliant idea.

一般人可能不会再去多想这个问题。但是，对于学习流体力学的陈濮阳和李启章来说，却是个不错的点子。

Soon, Chen, Li and several classmates embarked⁵ on the project. The design of the device required knowledge from a variety of different majors, so the team eventually came to be composed of seven students from various majors.

不久，陈濮阳、李启章和几个同学开始着手这个计划。装置的设计需要各种专业知识，所以团队最终由7名来自不同专业的学生组成。

"We put different kinds of dirt on our hands and washed them with water. It turned out that 95 percent of water is used to flush away the dirt; only 5 percent is used to dissolve it.

李启章解释道：“我们用水来冲洗手上的各种污渍，发现95%的水都用于冲走污渍，只有5%的水用于溶解污渍。

If we washed with only air, then the dirt on our hands would not dissolve. So we decided⁶ to use a fine water spray to complement⁷ the air. That way, the dirt is carried away by air and dissolved by water," explained Li.

如果我们用空气来冲洗手的话，手上的污渍则无法溶解。所以我们决定用水喷雾来弥补空气的缺陷。用这个方法，污渍能被水溶解然后被空气带走”。

After a year of research and experimentation⁸, the team came up with a gravity-driven hand-washing device whose reliance on water was minimal⁹.

经过一年的研究实验，这一团队想出了重力驱动洗手装置，此装置耗水量极少。

The user stands on a platform in front of the device, which sinks because of the weight of the user.

当使用者站在洗手装置前的踏板上，踏板由于人体重力而下沉，

The gravity exerted by the user pulls the piston¹⁰ through a pulley block, and a gust of air is generated through air extrusion¹¹. The tap then releases a water mist coupled with the gust.

人体的重力通过滑轮组，牵引活塞挤压空气获得高速气流，令水龙头喷出水雾来。

The team tested the device by conducting chromogenic reaction and residual¹² bacteria experiments, which proved that the results of hand-washing with air can be similar to those of washing with water.

该团队还通过显色反应和细菌残留实验来测试装置。实验证明空气洗手的效果和那些用水洗手的效果并无差异。

In September 2015, the team took its invention to the Global Grand Challenges Summit. They took home the top award, beating teams from 14 universities including MIT and Cambridge.

2015年9月，他们带着这项发明参加了全球重大挑战峰会。最终他们击败了包括麻省理工学院和剑桥大学在内的14所大学，拿到了最高奖项。