The invention discloses a sleeving method of inner and outer containers of an LNG (
Liquefied Natural Gas)
storage tank. The sleeving method comprises the steps of (1) preparing an outer container; (2) preparing an inner container; (3) preparing for sleeving; and (4) sleeving. Holes are formed in upper support points of the A-A and B-B support sections of the outer container, backing plates II are welded on lower support points of the A-A and B-B support sections of the outer container, an outer support ring is welded on a lower
support point of the A-A section, and a
glass fiber reinforced plastic support is inserted. Backing plates and an inner support ring are welded on support points of the inner container. The inner container is fixedly connected with a counterweight container, a connecting steel
pipe is lifted, and the inner container is moved to sleeve. When the B-B section of the inner container reaches an inlet, the outer support ring sleeves the outer surface of the
glass fiber reinforced plastic support filled with heat insulating materials, the
glass fiber reinforced plastic support is pressed into the lower inner support ring, and the outer support ring and the glass
fiber reinforced plastic support are supported to sleeve together with the inner container. In a specified position, the inner container falls so as to compress the glass
fiber reinforced plastic support. The outer support ring of the B-B section is welded on the backing plate II, and then the upper support structure is welded, so that sleeving is completed. According to the sleeving method, the full
penetration rate of the outer container is increased, leakage points of the outer container are reduced, and the vacuum
leakage rate of an interlayer between the inner and outer containers is reduced.