Negative pressure type sand sucker

The invention discloses a negative pressure type sand sucker which comprises a movable rack, at least one negative pressure tank arranged below the rack, at least one negative pressure pump arranged below the rack, and at least one negative pressure pump arranged below the rack, two main sand suction pipes are symmetrically arranged on the side wall of the lower portion of each negative pressure tank, the two main sand suction pipes are both communicated with the negative pressure tanks, the two main sand suction pipes are both obliquely arranged towards one sides of the negative pressure tanks, and the side walls of the two main sand suction pipes are both communicated with a plurality of auxiliary sand suction pipes; a suction nozzle is arranged at the end part of each secondary sand suction pipe, each secondary sand suction pipe is connected with the main sand suction pipe through a first elbow, a back-flushing pipe is vertically arranged on the first elbow, all the back-flushing pipes are communicated wit