Pipeline sight glass device capable of being cleaned on line

The utility model belongs to the technical field of pipeline sight glass, in particular to a pipeline sight glass device capable of being cleaned online, which is characterized in that a lower connecting pipe, a lower connecting plate, a glass sight glass pipe, an upper connecting plate and an upper sleeve are sequentially and fixedly arranged above a pipeline loop, and a connecting rod is arranged in the upper sleeve and the glass sight glass pipe from top to bottom in a penetrating manner; a glass tube inner wall cleaning device is arranged at the tail end part of the connecting rod in the glass sight glass tube, an operating device for driving the connecting rod to move up and down is arranged at the top end part of the connecting rod, one side of the upper sleeve is communicated with a circulating tube, and an outlet of the circulating tube is connected to a circulating loop of the pipeline. The sight glass device has a good online cleaning effect, guarantees good definition and observation effect in the