Pressure reduction type backflow preventer cycle test platform and test method

The invention discloses a cyclic test platform and test method for a pressure reduction type backflow preventer, and belongs to the technical field of pressure reduction type backflow preventers. The cyclic test platform comprises a variable frequency pump, an inlet control valve, a tested backflow preventer, an outlet control valve, an inlet cavity of the tested backflow preventer, a middle cavity and an outlet cavity which are connected in sequence; an inlet cavity pressure sensor, a middle cavity pressure sensor and an outlet cavity pressure sensor are respectively arranged on the front end of the inlet control valve and the front end of the outlet control valve, the front end of the inlet control valve is communicated with the front end of the outlet control valve through a branch pipe, and the branch pipe is provided with a pressurizing normally-closed electromagnetic valve for controlling on-off. A pipeline between the inlet control valve and the inlet end of the tested backflow preventer is provided wi