Liquid oxygen and liquid nitrogen preparing device

The utility model relates to a liquid oxygen and liquid nitrogen preparing device. The device comprises a self-cleaning air filter, an air compressor, an air conditioning unit, a separator, a molecular sieve adsorber, a main heat exchanger, a lower tower, an upper tower, a subcooler and an expander. The device adopts air as a raw material, the air sequentially passes through the self-cleaning air filter, the air compressor, the pressure increasing end of the exchanger, the air conditioning unit and the molecular sieve adsorber, and then enters a cold box, the air enters the main heat exchanger, a part of air is pumped out from the lower middle part of the main heat exchanger and then enters the expanding end of the turbo expander so as to subjected to adiabatic expansion, and the expanded air is sent out of the cold box after being reheated by a heat exchanger; the rest part of air is cooled to a liquefaction point, gets out of the main heat exchanger and then enters the lower tower to be rectified. Liquid ox