Negative pressure steam double-effect falling film concentrator

The invention relates to the technical field of double-effect falling film concentrators, and discloses a negative pressure steam double-effect falling film concentrator which comprises two sets of concentration towers, each concentration tower comprises a main shell, a steam collection bin communicated with the main shell is fixedly installed on the bottom end face of the main shell, and a liquid collection pool communicated with the steam collection bin is fixedly installed on the lower end face of the steam collection bin. A distribution bin is fixedly installed on the top end face of the main shell, multiple sets of falling film pipes are evenly and fixedly installed on the bottom end face of the distribution bin, the falling film pipes penetrate through the distribution bin and extend into the steam collecting bin through the main shell, a rotating shaft capable of rotating around the axis of the rotating shaft is movably installed in the middle of the bottom end face of the distribution bin, and a scrap