Dry type vacuum system

The utility model belongs to the technical field of vacuum systems, and particularly relates to a dry type vacuum system. The dry type vacuum system comprises a vacuum container, wherein an air outlet of the vacuum container is communicated with an air suction port of a screw vacuum pump by a forevacuum pipeline, the air suction port of the screw vacuum pump is also connected in series with at least two stages of roots vacuum pumps in sequence by a preceding-stage pipeline, an air suction port of the series first-stage roots vacuum pump is communicated with the air outlet of the vacuum container by a high vacuum pipeline, and the forevacuum pipeline, the preceding-stage pipeline and the high vacuum pipeline are respectively provided with a pre-pumping valve, a preceding-stage vacuum valve and a high vacuum valve. The dry type vacuum system is high in vacuum degree, running components are not contacted with one another and are stable to run and low in noise, pump cavities of the screw vacuum pump and the roots vacuum pumps have no oil and water, the dry type vacuum system is especially applicable to anhydrous reaction, and has no pollution to a pumped air medium, thereby being beneficial to recovery of raw materials or products entrained in tail gas, avoiding the waste of raw materials or products, saving the cost and reducing the environment pollution.