Vacuum-pumping method and apparatus thereof

Abstract

The present invention discloses an evacuation method and its equipment for evacuating sandwich between external barrel and internal barrel of multi-layer heat-insulating container. Said evacuation equipment includes first gas-conveying device, it has a gas outlet; first gas heater, its inlet is communicated with gas outlet of first gas-conveying device, its outlet is communicated with gas inlet of said internal barrel; evacuation machine unit, it is communicated with said sandwich; second gas-conveying device, it has a gas outlet; and second gas heater, its inlet is communicated with gas outlet of said second gas-conveying device, and its outlet is communicated with said sandwich.

Description

technical field [0001] The invention relates to a vacuum pumping method and its device, in particular to a vacuum pumping method and its device which can significantly improve the vacuum pumping efficiency and vacuum degree. Background technique [0002] Cryogenic liquid storage tanks, cryogenic liquid tanks, and cryogenic liquid tank trucks for storage of liquid nitrogen, liquid oxygen, liquid hydrogen, liquid argon, and liquefied natural gas that require extremely high insulation performance at home and abroad, the insulation form is mostly high-vacuum multi-layer insulation , the vacuum degree must be below 0.03Pa absolute pressure. For cryogenic liquid storage tanks of tens of square meters, the vacuuming time of the interlayer itself is very long, and because the heat insulating material in the interlayer has strong air absorption and large suction resistance, the moisture absorbed in the heat insulating material is difficult to extract. There are two common existing ...

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Problems solved by technology

Although this method can achieve the vacuum degree required by the specification, because the vacuum itself has thermal insulation properties, it is difficult for external heating to transfer heat to the thermal insulation material, and the entire heating replacement vacuum pumping process takes a long time; The gas is filled into the interlayer for heating and replacement, such as a method for vacuuming a liquefied natural gas storage tank for replacing air disclosed in CN03152769.8, but this method has a low thermal energy utilization rate and is not easy to operate. It is only used for containers with low vacuum requirements and does not Suitable for high vacuum multi-layer insulation containers

The above two methods all need to spend a lot of manpower, material resources and financial resources, and the manufacturing cost is very high, and the cryogenic liquid storage tanks, tank boxes and tank trucks manufactured by the existing vacuum technology, the moisture in the insulating material in the interlayer It is difficult to completely remove, and the remaining moisture will continuously release water vapor after vacuum sealing, resulting in a gradual decrease in the vacuum degree of the interlayer and a decrease in thermal insulation performance

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