JZJ2S type Roots-water ring vacuum system consists of the major pump i.e. ZJ type Roots vacuum pump and the backing pump i.e. two stage water ring vacuum pump. It can pump not only the common gas but also the gas that contains vapor and a little dust. Compared with the common mechanical vacuum pump and water ring vacuum pump, it has some advantages as follows: it can endure the oil,vapor and tiny dust,its ultimate vacuum is high and its pumping speed in higher vacuum is great,so it is a kind of ideal vacuum-obtaining equipment for drying,dehydrating and gas-expelling in the trade of light-spinning,grocery and chemical industry etc..