Pretreatment device for water inlet on-line instrument room

The invention relates to the technical field of sewage monitoring pretreatment, and particularly discloses a pretreatment device of a water inlet online instrument room, which comprises a mounting frame with an open upper side, a first settling tank, a second settling tank and a third settling tank are sequentially arranged in the mounting frame, and a water outlet pipe and a filter plate are arranged on one side in the third settling tank. And a spiral blade with a hole is arranged in the first settling tank through a rotating shaft. The device can be arranged near a fine grid of a sewage plant, and can ensure enough high level difference, so that pretreated sewage flows to an instrument room pipeline by gravity, and the system is ensured to operate in an hour; the pretreatment is divided into a water pumping part, a sand settling and filtering main body part, a scum and filtering system, a sludge discharging system, a backwashing and surpassing system and the like, so that samples in a sampling pipeline of