US3355135A

US3355135A - Cargo tank support

Info

Publication number: US3355135A
Application number: US520320A
Authority: US
Inventors: Bengtsson Bengt Gunnar
Original assignee: Goetaverken AB
Current assignee: Goetaverken AB
Priority date: 1965-01-22
Filing date: 1966-01-13
Publication date: 1967-11-28
Anticipated expiration: 1984-11-28
Also published as: GB1071862A; NO118209B

Description

NOV. 28, 1967 Y 56 3,355,135

CARGO TANK SUPPORT Filed Jan. 15, 1966 United States Patent 3 Claims. (Cl. 248-350) ABSTRACT OF THE DISCLOSURE A support for a cargo tank subjected to thermal movements, e.g. for transporting cryogenic gases, consists of members having different height in unloaded condition, the taller of said members being widely spaced and designed alone to carry the container in empty condition and to permit a limited sideward movement of the container bottom in relation to the support base, whereas the shorter members are located some distance from the tall ones and disposed in such a manner that the bottom of the tank during loading and simultaneous cooling will reduce its size before it is lowered down onto the shorter members.

The present invention relates to cargo ship structures and is concerned with the provision of novel means for supporting a container subjected to thermal movements, especially a cargo tank in a ship. Resilient support means are necessary when the temperature of the cargo differs materially from that of the ambient temperature. This is the case, for instance, when condensed gases are transported at atmospheric pressure, but the invention may also be utilized for containers adapted to carry heated cargo.

In designing such supports the following (amongst other) demands must be met:

(a) thermal movements of the container mitted to take place;

(b) the considerable weight of the filled container must be transferred to the support base;

(c) the support members must be as poor conductors of heat as possible;

(d) the container must retain frictional contact with the base.

Hitherto known proposals take some but not all of these points into consideration simultaneously and, thus, are compromises only.

One object of the present invention is to design a support means fulfilling all demands above stated, and which at the same time is economically favorable due to its simple construction.

A further object of the invention is to design the support means whose support members are not directly influenced by the low temperature prevailing in the container.

The design is based on the consideration that the temperature of the container initially is slowly brought down to the working temperature by the introduction of small quantities of the cargo (condensed gas), in such a manner that the contraction (or, reversely, the expansion) is mainly completed before the main loading takes place. By having the container resting on a few support members only during the contraction (or, expansion) period, which support members are designed to permit a limited movement between the container and the support base, it is possible to take care of thermal movements in all directions without undue stresses occurring. During the ensuing loading of the container a reduction of the height of the supports will take place in such a manner that must be percertain parts of the container bottom structure (or, of support members fitted thereto) will support the container.

The invention is illustrated by way of example in the attached drawing, in which:

FIGS. 1-3 inclusive schematically show a container according to the invention in three different loading positions-first empty, thereafter carrying an insignificant portion of cargo only, and finally practically filled;

FIG. 4 is a side View, on a larger scale, of the support arrangement according to the invention;

FIG. 5 is a section along line VV in FIG. 4; and

FIG. 6 illustrates a modification of the support member shown in FIG. 5.

In FIGS. 1-3 inclusive a container is denoted by 1, and a support base for the same is denoted by 2. This support base forms part of a construction, for instance the cargo hold of a ship, enclosing the container 1. Primary support members according to the invention are indicated by 3 and between these are arranged further relief supports 4, designed as shims or the like. Means for fixing the center of the bottom of the container 1 in relation to the support base 2 without transferring any vertical load are indicated by 5.

FIG. 1 shows the container 1 at normal temperature and Without any cargo. The support members 3 are designed in such a manner that they will then carry the container with the lower surfaces of relief supports 4 free from the base 2.

In FIG. 2 a small amount of cargo-for instance cool, condensed gashas been introduced into the container 1, which due to the low temperature of the cargo will contract from the position indicated by dash-dotted lines to the position 1' shown in full lines. This position will mainly correspond to the maximum contraction caused by the cargo in question. It will be noted that the amount of cargo introduced for this purpose is insufiicient to depress the container to such a degree that the relief support surfaces fitted to the bottom of the container contact the support base.

In FIG. 3 the container is practically filled with cargo and its walls are disposed in position 1 shown. Due to the weight of the cargo the support members 3 have now been compressed in such a manner that the distance between the container bottom and the base is reduced: the relief support surfaces 4 now carry the whole or an essential part of the weight of the container and cargo.

An embodiment of the invention wherein the demands for highly eficient insulation below the container is met is shown in detail in FIGS. 4 and 5. Distance blocks 6 of insulating material, for instance slabs of wood glued together, are fitted to the bottom of the container and between the sides of these blocks insulation material, not shown, is arranged. These distance blocks are permanently fixed to the bottom structure of the container and the support members 3 are fitted to the underside of the blocks. In this embodiment the support members consist of a resilient material, for instance rubber or synthetic resin, and are preferably glued to the underside of the blocks and to channel-shaped mountings 7 at the support base 2. The location at the underside of the insulating blocks protects the support members from the low temperature prevailing in the container and the material thereof retains its resilient properties.

The underside of the blocks, may, between the places where the primary supports are fitted, to be shaped in different ways depending on the magnitude of the movements which may be expected between them and the support base. In blocks arranged close to the center of the container it may, for instance, be suitable to design the relief support surfaces 4 as parts 8 of the distance blocks 6 proper (right part of FIGURE 5). Towards the periphcry of the container bottom the movements between container and support may be considerable. If, furthermore, the support base forms part of a longitudinal strength member of a ship it will be subjected to alternating hogging and sagging movements when the ship moves through the waves. In these cases the relief supports 4 may consist of slabs 9 of rubber or synthetic resin fitted to the blocks in appropriate places. These slabs are, however, thinner than the first-mentioned type of support members, 3, and are made from a material which is considerably less compressible than is the material in members 3.

The support members 3 are made from such a compressible material and are designed in such a manner that lateral movement of the container in relation to the base may occur. The material in the support members 3 is adapted to be elastically deformed, and will, for a certain amount of load, be compressed sufficiently to bring the surfaces of relief supports 4 into action. The required amount of load for this purpose may be chosen according to circumstances. Usually a certain amount of cargo is left in the tank, when this is unloaded, to keep the temperature of the tank low and possibly also to serve as fuel during the return voyage. It is recommended that the amount of retained cargo be suflicient to keep the container in its lower condition, even after the consumption during the voyage.

FIG. 6 shows a modification of the support members 3 which here are designed as prismatic blocks, links or the like, 10, of non-compressible material, for instance wood, steel or the like. These members 10 are mounted on pivots 11 carried by pairs of brackets 12 connected to the container bottom 1 and to the support base 2, respectively, and are provided with rounded upper and lower contact surfaces in such a manner that a reduction of the height is brought about by a relative movement between container and support base.

I claim:

1. Means for supporting a container subjected to thermal movements, especially a cargo tank in a ship, in relation to a support base by means of members having different heights in unloaded condition; comprising:

a plurality of a first type of widely spaced relatively tall support members attached to the container bottom structure as well as to the support base, said first type support members being designed alone to carry the empty container at a distance from the support base and to permit a limited movement of the container in relation to said support base;

a plurality of a second type relatively short support members being fixed to either the bottom structure of said container or to the base support at a distance from said first support members, whereby during an initial decrease in temperature of the container a relative movement between said container and the support base may take place before support members of said second type become engaged for carrying purposes.

2. Supporting means according to claim 1, characterized in that said first type of support members are formed of a resilient rubber-like material.

3. Supporting means for supporting a container subjected to thermal movements, especially a cargo tank in a ship, in relation to a support base by means of members permitting a limited movement of the container in relation to said support base, comprising: a plurality of a first type of widely spaced support members attached to the container bottom structure as well as to the support base, said first type support members serving to carry the empty container at a distance from the support base; and a plurality of a second type support members the height of which is less than that of said first members when said first support members are unloaded; said second type of support members being fixed to either the bottom structure of said container or to the base support and located in such relation to said first support members that during an initial decrease in temperature of the container a relative movement between said container and the support base may take place without the second type of support members being engaged, whereas during continued loading of the container said first type of support members are displaced sufficiently to reduce the distance between the bottom of the container and the support base such that the container in loaded condition is carried by both of said two types of support members and wherein said first type of support members consist of prismatic links formed of a non-compressible material and having rounded upper and lower contact surfaces and being pivotally connected to the container bottom structure and to the supporting base, respectively.

References Cited UNITED STATES PATENTS 3,026,577 3/1962 Dosker 114-74 X FOREIGN PATENTS 134,150 7/1933 Austria.

RAY D. FRAZIER, Primary Examiner.

CHANCELLOR E. HARRIS, Examiner.

F. DOMOTOR, Assistant Examiner.

Claims

1. MEANS FOR SUPPORTING A CONTAINER SUBJECTED TO THERMAL MOVEMENT, ESPECIALLY A CARGO TANK IN A SHIP, IN RELATION TO A SUPPORT BASE BY MEANS OF MEMBERS HAVING DIFFERENT HEIGHTS IN UNLOADED CONDITION; COMPRISING: A PLURALITY OF TYPE OF WIDELY SPACED RELATIVELY TALL SUPPORT MEMBERS ATTACHED TO THE CONTAINER BOTTOM STRUCTURE AS WELL AS TO THE SUPPORT BASE, SAID FIRST TYPE SUPPORT MEMBERS BEING DESIGNED ALONE TO CARRY THE EMPTY CONTAINER AT A DISTANCE FROM THE SUPPORT BASE AND TO PERMIT A LIMITED MOVEMENT OF THE CONTAINER IN RELATION TO SAID SUPPORT BASE;