Device for reducing temperature of expansion tank in boiler circulation heating system

The utility model discloses a device for reducing temperature of an expansion tank in a boiler circulation heating system. The device comprises an expansion tank, an oil-gas separator, a first buffer tank and a second buffer tank, wherein the oil-gas separator is provided with three connectors, one end is connected with an oil return pipeline, one end is connected with a pre-pumping pipeline, the other end is connected with the first buffer tank through a first expansion pipe, the lower part of the first buffer tank is connected with the upper part of the second buffer tank through a second expansion pipe, the lower part of the second buffer tank is connected with the expansion tank through a third expansion pipe, discharge outlets are arranged on the bottom parts of the first buffer tank and the second buffer tank, exhaust ports are arranged on the top parts of the first buffer tank and the second buffer tank, the second buffer tank is internally provided with at least two partition plates, the partition plates are provided with openings, none of the openings are at the same vertical line, and inner space of the second buffer tank is divided into at least three layers of space. The device provided by the utility model is simple in structure, convenient to use, and capable of effectively reducing the temperature inside the expansion tank.