A multi-level control device for liquid nitrogen vaporization temperature for fruit and vegetable preservation

Abstract

A multi-level control device for liquid nitrogen vaporization temperature for fruit and vegetable preservation, comprising a liquid nitrogen tank, a temperature sensor, a temperature control box, a liquid storage tank, a liquid inlet pump, a liquid outlet pump, and a control module; the liquid storage box is filled with cold storage The outlet of the liquid storage tank is connected with the cold storage inlet of the temperature control box through the liquid inlet pump, and the cold storage outlet of the temperature control box is connected with the inlet of the liquid storage tank through the liquid outlet pump; there are at least two tubes in the temperature control box Serpentine gasification tubes used to transport liquid nitrogen with different lengths, the outlet of the liquid nitrogen tank is connected to the inlet of the gasification tube, and the outlet of the gasification tube is connected to an output tube; the inlet of the gasification tube There is a normally closed solenoid valve at the mouth, and the temperature sensor is set on the output pipe to obtain the temperature after the liquid nitrogen is vaporized. The control terminals of the liquid pump and the liquid outlet pump are electrically connected. The invention realizes step-by-step regulation and control of the temperature of the nitrogen gas after gasification, so as to avoid harm to products.

Description

technical field [0001] The invention relates to a multi-stage control device for liquid nitrogen vaporization temperature for fruit and vegetable preservation. Background technique [0002] At present, fruits and vegetables are generally transported in the way of controlled atmosphere fresh-keeping transportation, and the advantage of this transportation method is that it can prolong the fresh-keeping period and Guarantee the quality of fruits and vegetables. [0003] During the transportation of fruits and vegetables, the respiration of fruits and vegetables is suppressed by controlling the composition of the ambient gas in the box, thereby prolonging the preservation period of fruits and vegetables. At present, the existing controlled atmosphere methods are: spontaneous controlled atmosphere, two-phase variable controlled atmosphere, and decompression controlled atmosphere. These methods of air conditioning generally have problems such as low air conditioning efficiency ...

AI Technical Summary

Problems solved by technology

[0004] However, there will be the following problems in the liquid nitrogen filling atmosphere: on the one hand, the nitrogen is stored in the liquid nitrogen tank in the form of liquid, and the temperature of the stored liquid nitrogen is minus -196 ° C, when the liquid nitrogen is directly When entering the box, it will cause low temperature damage to the fruits and vegetables in the box

Liquid nitrogen is vaporized and heated by absorbing the heat of the air outside the vaporizer pipe. Since the temperature of the nitrogen after heating cannot be controlled, there is no guarantee that the nitrogen will not cause harm to the product.

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