To control the freezing rate of livestock semen and correct access to frozen semen. The size of liquid nitrogen cryogenic tank container, the depth of liquid nitrogen, the purity of liquid nitrogen vapor density of 3 factors.
When frozen semen was produced by liquid nitrogen as refrigeration medium, the freezing rate was determined by the rate of freezing semen, the rate of completeness and fertilization rate. In the freezing process, the freezing of fine tubular semen is accomplished in the liquid nitrogen vapor between liquid nitrogen surface and container mouth plane in cryogenic vessel. The initial temperature of the freezing plane of the semen tube is one of the important factors influencing the freezing rate of the liquid nitrogen vapor temperature in a plane at a cryogenic storage tank.
The results showed that:
1 The temperature distribution in the cryogenic tank of liquid nitrogen is determined by the distribution of the vapor density of liquid nitrogen, which is influenced by the vessel structure;
2 There is a critical plane in the cryogenic tank of liquid nitrogen, the temperature of the critical plane above varies, below the critical plane, the temperature difference of each plane is not significant or no difference;
3 The lower the level of liquid nitrogen cryogenic storage tanks, the lower the temperature, the drop is not uniform.