Liquid nitrogen filling machine

Abstract

The invention provides a liquid nitrogen filling machine and belongs to the field of auxiliary devices for food packaging. In order to be beneficial to stable control of the liquid nitrogen filling pressure, the liquid nitrogen filling machine is provided. The liquid nitrogen filling machine comprises a heat-preserving storage cylinder, a heat-preserving filling head and a heat-preserving liquid conveying pipe, and further comprises a first pressure leading pipe and a second pressure leading pipe, wherein a top-end mounting hole which extends into the inner cavity of the heat-preserving storage cylinder is formed in the top end of the heat-preserving storage cylinder; a bottom-end mounting hole which extends into the inner cavity of the heat-preserving storage cylinder is formed in the bottom end of the heat-preserving storage cylinder; one end of the first pressure leading pipe is mounted at the top-end mounting hole; the other end of the first pressure leading pipe extends to a position I above the heat-preserving storage cylinder; one end of the second pressure leading pipe is mounted at the bottom-end mounting hole; and the other end of the second pressure leading pipe extends to a position II above the heat-preserving storage cylinder. By adoption of the liquid nitrogen filling machine, errors caused by temperature hysteresis and a floating ball can be eliminated, the measure pressure value precision can be improved, and the liquid nitrogen filling pressure and the height of a liquid level can be correctly controlled, thereby guaranteeing the liquid nitrogen filling stability.

Description

technical field [0001] The invention belongs to the technical field of food packaging auxiliary devices, in particular to a liquid nitrogen filling machine. Background technique [0002] Liquid nitrogen filling is widely used in food canning and other fields. Liquid nitrogen filling machine is an important equipment for liquid nitrogen filling, which directly affects the efficiency of liquid nitrogen filling. The Chinese invention patent application with the application number 201320725102.0 discloses a liquid nitrogen filling machine, which has a compact structure and good quality of the pure liquid phase of liquid nitrogen. In this liquid nitrogen filling machine, the floating ball floats with the liquid surface of the liquid nitrogen in the heat preservation storage cylinder. When the floating ball seals the middle hole of the spacer and the pressure of the liquid nitrogen above the spacer reaches the set value, the pressure sensor sends out a signal. The control stops t...

AI Technical Summary

Problems solved by technology

However, due to the low temperature of liquid nitrogen, the floating ball is easy to freeze, and the frozen floating ball cannot guarantee to strictly seal the middle hole of the column spacer, so the pressure sensor cannot accurately transmit the information of stopping the continuous delivery of liquid nitrogen

Moreover, the pressure sensor has temperature hysteresis, which cannot eliminate the influence of temperature error, and the accuracy of the measured pressure value is low

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