LOW-TEMPERATURE FULL-CAPACITY TANK FOR REALIZING LOW LIQUID LEVEL MATERIAL EXTRACTION FUNCTION BY USING PUMP COLUMN

Provided is a low-temperature full-capacity tank for realizing a low liquid level material extraction function by using a pump column, comprising an inner tank (1), an outer tank (2), a pump column (3), a submersible pump (4) and a material pre-extraction device (5); wherein the material pre-extraction device (5) comprises a cofferdam (51), a Venturi mixer (52), a backflow pipe (53), a return control valve (55), a lead-out pipeline (54) and a liquid level detection system (56); wherein the cofferdam (51) is located at the bottom of the inner tank (1) and surrounds the outside of the pump column (3); the height of the cofferdam (51) is greater than the minimum liquid level required for the normal operation of the submersible pump (4); the Venturi mixer (52) is installed at the bottom of the inner tank (1) and located outside the cofferdam (51), with a suction hole (5202) on the outer circumference thereof; the backflow pipe (53) is connected to the upper part of the pump column (3) to the inlet of the Venturi mixer (52); the return control valve (55) is set on the backflow pipe (53); and the lead-out pipe (54) is connected to the outlet (5203) of the Venturi mixer (52) to the inside of the cofferdam (51). The low-temperature full-capacity tank can make use of a low-temperature medium flowing back from the pump column (3) to extract the low liquid level material outside the cofferdam (51) into the cofferdam (51) to form a local high liquid level and maintain the normal operation of the submersible pump ( 4), thereby reducing the lower limit of the operating liquid level in the tank and improving the volume utilization rate.