Abstract A method of hydraulically testing low temperature liquefied gas tanks of a membrane type, said tank comprising a rigid outer vessel, a heat insulating intermediate layer and an inner membranous vessel, wherein said inner membranous vessel is of an angular shape including substantially flat portions and curved edge and corner portions and is adapted to be smoothly supported by the inside surface of the heat insulating intermediate layer under contraction due to low temperature as well as expansion by internal pressure when the inner vessel is loaded with low temperature liquefied gases, though the inner vessel is formed as over-sized at atmospheric temperature than a space defined by the inside surface of the heat insulating layer in consideration of said contraction, the method being characterized by positively supporting said flat portions of the inner vessel in an expanded condition when the inner vessel is filled with water at atmospheric temperature so that no wrinkling due to margins for said contraction is formed at the time of hydraulic test executed at atmospheric temperaure.
A method of hydraulically testing low temperature liquefied gas tanks of a membrane type, said tank comprising liquid outer vessel, a heat insulating intermediate layer and an inner membranous vessel, wherein the said inner membranous vessel is of an angular shape including substantially flat portions and curved edge and corner portions and is adapted to be smoothly supported by the inside surface of the heat insulating intermediate layer under contraction due to low temperature as well as expansion by internal pressure when the inner vessel is loaded with low temperature liquefied gases, though the inner vessel is formed as oversized at atmospheric temperature than a space defined by the inside surface of the heat insulated layer to have a margin for said contraction, characterized by biasing said margin at atmospheric temperature to said curved edge portions so that said flat portions come into close contact with the inside surface of said heat insulating layer, and filling the space in said inner vessel with water at atmospheric temperature.
Claim 2
Independent Claim
167 words
A method of hydraulically testing low temperature liquefied gas tanks of a membrane type, said tank comprising liquid outer vessel, a heat insulating intermediate layer and an inner membranous vessel, wherein the said inner membranous vessel is of an angular shape including substantially flat portions and curved edge and corner portions and is adapted to be smoothly supported by the inside surface of the heat insulating intermediate layer under contraction due to low temperature as well as expansion by internal pressure when the inner vessel is loaded with low temperature liquefied gases, though the inner vessel is formed as oversized at atmospheric temperature than a space defined by the inside surface of the heat insulated layer to have a margin for said contraction, characterized by biasing said margin at atmospheric temperature to said curved edge portions so that said flat portions come into close contact with the inside surface of said heat insulating layer, and filling the space in said inner vessel with water at atmospheric temperature.
Claim 3
Dependent Claim
52 words
A method according to claim 1, wherein said biasing of the margin is effected by that an edge block adapted to support said edge portion is provisionally retracted from its normal mounting position so as to allow bulging said curved edge portion outwardly as much as to absorb said margin for contraction.
Claim 4
Dependent Claim
33 words
A method according to claim 1, wherein said biasing of the margin is effected by the said substantially flat portion is partly pressed by pad plate from the inside of the inner vessel.