Negative pressure drainage (NPD) technology is required to extract chyme from the gastric cavity of the patient suffering from stomach disease in order to observe the mucosal condition of the gastric cavity clearly and to avoid being misdiagnosed in gastroscopy. However, there are problems, such as insufficient vacuum and easy clogging, in the current NPD devices. To deal with these problems, by applying the principle of hydraulic check valve, a novel device, convenient to extract chyme from

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... tric cavity, is discussed in this article, which will meet the clinical demand. The proposed new device has the advantages of enough vacuum degree, smooth drainage without backflow and blockage, and has a better application prospect as compared to existing devices.