The safety overflow valve is used in internal pumps “JONSON” for transport of liquid with pressure of 5 Bar with different consistency used in food industry, as chocolate, cacao, vegetable products and etc. The viscosity of used materials for these products is from 60 to 460 µPas. This valve is an object of design and constructive documentation for purposes of teaching process on “ Principles of Mechanical design and CAD”. On Fig.1 is shown a safety overflow valve that is put on outflow of pump. In Fig.2 is shown the partial section of its nature common view.