Zero-consumable self-restoring high-pressure digestion combined tank

The invention provides a zero-consumable self-restoring high-pressure digestion combined tank for a microwave digestion instrument. The zero-consumable self-restoring high-pressure digestion combined tank is used for digesting a sample to be detected and comprises a sample dissolving cup and an outer tank; the sample dissolving cup comprises a sealing piston, a sealing cover and a cup body; the sealing piston is inserted into the cavity of the sealing cover; the sealing wall of the sealing cover is inserted into the cavity of the cup body; the outer tank comprises a tank cover and a tank body; the tank cover and the tank body are in screwed connection; the sealing cover and the cup body are tightly pressed between the tank cover and the tank body, so that the sealing effect of the sample dissolving cup is good; when the pressure in the sample dissolving cup is changed, the sealing cover and the cup body are fixed; the sealing piston can move in the direction away from or close to the cup body; and when the sealing piston moves to a pressure relief opening of the sealing cover, gas in the sample dissolving cup can be released, so that pressure is relieved. The zero-consumable self-restoring high-pressure digestion combined tank disclosed by the invention has the advantages of being zero-consumable, and therefore, the zero-consumable self-restoring high-pressure digestion combined tank can be reutilized for a long time, and the production and use cost is reduced; being good in sealing effect regardless of high and low pressure in the sample dissolving cup; and realizing self-restoring sealing and being high in security coefficient.