Water meter calibrating device with purging function

The utility model relates to a water meter calibrating device with a purging function, which comprises a gas tank, a water tank, a piston and a moving device for controlling the piston to stretch out and draw back, one end of the piston is connected with an exhaust pipe, a water outlet pipe and a water inlet pipe, and a first exhaust valve is arranged on the exhaust pipe. One end of the water outlet pipe and one end of the water inlet pipe are both connected with the water tank, a water pump is installed on the water inlet pipe, and a first drainage valve, an air blowing pipe, a detected meter, a second drainage valve and an electromagnetic flowmeter are sequentially installed on the water outlet pipe in the direction from the piston to the water tank; a second exhaust valve is installed in the middle of the air blowing pipe. According to the utility model, the requirements of verification, calibration and delivery inspection of the liquid flow meter and the continuous growth trend of novel flow meter product