Metering pump on-line monitoring cylinder and material secondary monitoring method thereof

The invention relates to an on-line monitoring cylinder for a metering pump. The on-line monitoring cylinder comprises a buffer tank, an air cylinder, a connecting shaft and a scale sensor, a piston is arranged in the buffer tank, the top of the piston is connected with the lower end of a connecting shaft, and the upper end of the connecting shaft penetrates through the top of the buffer tank to be connected with a piston rod of an air cylinder. A cavity located at the lower end of the piston in the buffer tank is a feeding cavity, one side of the feeding cavity is connected with a blender, and the other side of the feeding cavity is connected with a discharging pipe through a discharging valve; a scale sensor is arranged on the outer side of the buffer tank, a horizontal connecting rod is arranged on the connecting shaft, and a measuring ruler on the scale sensor is connected with the connecting rod. The online monitoring cylinder of the metering pump is used for secondary monitoring after material proportio