| Aquatic products with high nutritional value are easy to corrupt.Low temperature preservation is an important measure in preservation technology.At present,cold air preservation technology,cold water preservation technology and ice preservation technology are commonly used in market.The lower the temperature,the better quality of the preservation.In order to obtain high-quality aquatic products,liquid nitrogen freezing technology has greater advantages.However,the high cost of liquid nitrogen restricts the application of this technology aquatic products preservation.In addition,fishing is the weak link in cold chain of aquatic products.Thus,it is of great practical significance to improve the utilization of liquid nitrogen for the popularization of liquid nitrogen freezer.Firstly,the research progress of liquid nitrogen freezer was analyzed and the disadvantages of the liquid nitrogen freezer were pointed out in this dissertation.Secondly,the design of the reversible device of spiral liquid nitrogen freezer was studied.The energy saving on the double-side cooling was achieved by turning the aquatic products during the process of quick freezing,which experiments were carried out to save about 21% of liquid nitrogen;The air distribution was optimized and was compared with four typical forms,for saving about 8% of the liquid nitrogen so that the vertical countercurrent swept airflow was selected and verified in the end;The design scheme of applying 6-DOF platform structure to liquid nitrogen tank was proposed,which greatly reduced the gasification loss of liquid nitrogen,vibration and improved the safety of liquid nitrogen.Finally,the prospects of improving the liquid nitrogen utilization of liquid nitrogen freezer for fishing vessels were put forward.This study had improved the liquid nitrogen utilization of liquid nitrogen freezer for fishing vessels effectively,which will play an important direct role in the application of liquid nitrogen freezer in transportation. |
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