Electromagnetic switching valve and piston type gas flow calibration system

The utility model discloses an electromagnetic switching valve and a piston type gas flow calibration system, the electromagnetic switching valve comprises a valve body, a fixed electromagnetic part and a movable iron core part, the valve body is provided with two gas inlet nozzles and two gas outlet nozzles, the fixed electromagnetic part and the movable iron core part are arranged in an inner cavity of the valve body, and the fixed electromagnetic part and the movable iron core part are arranged in the inner cavity of the valve body. And the fixed electromagnetic part is electrified to generate magnetic force to drive the movable iron core part to move towards or away from the air outlet nozzle so as to realize connection or disconnection of the bypass. The electromagnetic switching valve is a low-resistance and large-drift-diameter electromagnetic valve, is used in a bypass of a dry piston type gas flowmeter, can ensure the rising stability of a piston when detecting pulsating flow, and meanwhile, avoids v