Similar in structure to the rising film vacuum concentration equipment, it consists of a heater, evaporation separation chamber, partition condenser, vacuum pump, condensate extraction pump, sterilization balance tank, heat pump, and thermal instruments. The main difference is that the liquid is added from the top instead of the bottom. In order to evenly distribute the liquid material in each heating tube and flow down along its inner wall, a falling film distributor is installed at the top or inside the heating tube. The most critical issue for the efficient operation of the falling film concentrator is to evenly distribute the feed liquid in each heating tube without causing bias, so a falling film distributor is installed at the top or inside the tube. There are various types of distributors, which can be divided into three categories according to their working principles: one is to use guide pipes (plates) to evenly distribute the material and liquid; The second is to use sieve plates or nozzles to evenly distribute the liquid material; The third is to use a rotary liquid nozzle.

There are several types of liquid distributors commonly used in industrial equipment, including:

(1) Sieve plate, sieve plate generally uses two layers, but there are also those that use one layer of sieve plate.

(2) Spray distributor: the feed liquid is pressurized by the pump and then sprayed into uniform droplets through the nozzle.

(3) A guide pipe with serrated edges, surrounded by 3-4 radial support legs, placed on each heating pipe mouth; Another method is to protrude the heating tube from a certain height outside the tube plate, and process it into a serrated shape along the mouth. The liquid material is evenly distributed on the inner wall of the heating tube through the tooth gap.

(4) A guide pipe with 2-3 spiral grooves, surrounded by an annular support, the surface of which covers the pipe mouth, and the material liquid is evenly distributed along the spiral grooves on the inner wall of the pipe.

(5) The guide pipe is a cylindrical body with a spiral groove, and the lower part of the guide pipe is a cone. The bottom of this cone is concave to prevent the liquid flowing down along the surface of the cone from gathering towards the center.

(6) Combination of sieve plate and guide plate.

(7) Spiral liquid type, the material liquid is pressurized by a pump and enters the spiral distributor, using centrifugal force to evenly distribute the material liquid around the pipe.

The material liquid to be concentrated enters the heater from the top, and under the action of the material liquid distributor, it uniformly enters the heating tube. Under the rapid flow of secondary steam and its own gravity, the material naturally flows downward in a film shape along the inner wall of the tube, and is continuously evaporated and concentrated by heating. The concentrated feed liquid and secondary steam enter the separator for separation. The secondary steam is discharged from the top of the separator, and the concentrated liquid is discharged from the bottom. A key factor for the good operation of a falling film concentration tank is the uniform dispersion of the material on the heating surface. In order to evenly distribute the liquid material in each heating tube, flow down along the inner wall of the tube and install a falling film distributor at the top or inside the tube.