US3042080A - Means for moving extremely cold liquids - Google Patents

Description

July 3, 1962 c. D. DosKER MEANS FOR MOVING EXTREMELY com LIQUIDS Filed July 2. 195s United States Patent O 3,042,080 MEANS FR MOVING EXTREMELY COLD LlQUIDS Cornelius D. Doslrer, Louisville, Ky., assigner, by mesne assignments, to Couch International Methane Limited,

Nassau, Bahamas, a corporation of the Bahamas Filed July 2, 1953, Ser. No. 746,150 2 Claims. (Cl. 13S-100) This invention relates to a means for moving a liquid having a temperature differing widely from the ambient temperature and it relates more particularly to a means through which extremely cold liquid can be moved over a substantial distance without loss of liquid by leakage and without deterioration of the carrying means by reason of the lwide variations in temperature to which it is exposed in use.

This invention will be described with reference to natural gas that is liquefied and returned to storage for building up a supply to be transported to distant stations. Sometimes the distant station is separated from the source of supply by land and/ or by a large body o-f water whereby it becomes necessary to move the liquefied gas in large quantities over land to or from a transportation means. The transportation means may be represented by a ship fitted with large insulation tanks in which the liquid is housed for transportation from the source of supply to the area where the deficiency exists. It will be understood that the concepts of this invention will have application also to the movement of other liquefied gases or other liquids which need to be maintained at extremely low temperature.

The difficulties in the movement of large volumes of liquefied gas over land arises from the extremely low boiling point temperature of the liquid whereby it becomes necessary to maintain the liquefied gas at `a temperature below about 250 F. when, as is preferred, the material is moved at or about atmospheric pressure. Additional problems arise when the liqueed gas is periodically discharged frorn the land storage tanks to load the ships tanks or vice Versa. Thus the means in which the liquid is moved will be contacted for a short period of time with a liquid at about -250 F. and then exposed for a longer period of time to ambient temperature. As a result, the elements of which the moving means is constructed will be subjected to repeated cycles of temperature change in the order of. `about 350 F.

The great majority of metals are incapable of use under the extremely low temperature conditions existing while others are deficient from the standpoint of stability as affected by the repeated fluctuations in temperature. All materials capable of use expand or contract in response to temperature change, some to a greater degree than others. Thus problems arise as to the construction materials and methods of assembly to construct a means for moving large quantities of liquefied gas either in a continuous or in an intermittent stream, as described, and it is a problem to effect a suitable construction at low cost and of readily available materials.

It is an object of this invention to produce and to provide elements for use in producing `a means for moving large quantities of a liquid which needs to be maintained at extremely cold temperature and it is a related object to produce a means for the transmission of such cold liquid over fland in ya continuous or intermittent stream.

More specifically, it is an object of this invention to produce and to provide elements for producing `a fiume type transmission line of endless length which embodies structural `strength and stability to enable movement of a cold liquid at a high rate of flow over `a suibstantial distance; which is constructed of a `combination of elements 3,042,080 Patented July 3, 1952 ICC which are capable of use under the extreme cold to which the transmission line is continuously or periodically exposed; which is subject to little, if any, leakage in use; in which the liquid impermeability of the carrying means is improved in response to the passage of liquid therethrough; which is capable of being formed of prefabricated elements thereby to reduce the cost of materials and assembly; which is constructed of relatively inexpensive and readily available materials; which requires little maintenance and repair, and which embodies strength and durability for operation under heavy loads and under slight internal pressure, if necessary, for the transmission of liquid therethrough.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawings in which:

FIGURE l is `a perspective view of a fragmentary portion of a liquid moving means embodying the features of this invention;

FIGURE 2 is a sectional view of the moving means shown in FIGURE l in a final `stage of construction;

1FIGURE 3 is a sectional view similar to that of FIG- URE 2 embodying a modification thereof, and

FIGURE 4 is a perspective view similar to that of FIG- URE l showing the arrangement of elements in an intermediate stage of construction.

In accordance with the practice of this invention, a conduit 10 is formed of a tubular base member 12 of large dimension. The tubular base member is fabricated of a plurality of elongate staves 14 formed to curvilinear shape and sealingly joined one to the other in end-to-end relation to continuous 'lengths and in side-by-side relation to complete the tubular section. The staves are preferably formed of a hard or dense wood but they may be formed of wooden laminates, glass fiber reinforced plastics and the like materials capable of retaining their strength and ductility at the low temperatures to which they will be exposed.

The staves 14 are preferably formed to a minimum thickness, such as from 1/2 to 3 inches, in cross-section and to lengths which may be as great as 100 feet or more, depending upon the ease of handling, both in manufacture of the staves and their assembly. It is desirable to maintain uniformity in the construction of the stages to enable mass production and assembly thereof. For this purpose, it is desirable to produce staves of uniform length and to form each of the staves with an equivalent curvature corresponding to an arc which is a convenient division of 360 degrees. When, as illustrated in the drawing, the tubular base comprises rfive staves adhesively joined in side-by-side relation, each of the staves would be formed to an arc of about 72 degrees. If four staves were employed, the arc would be degrees, six staves 60 degrees, etc.

rPhe staves are each slotted at 16 about the exposed edges for alignment of the slots one with the others in in the adjacent staves arranged in side-by-side and in end-to-end relation to enable the insertion of a connecting spline 18 therebetween. The latter operates to transmit load from one stave to another for uniform distribution and in effecting a better sealing relationship between the staves when adhesively joined. A single spline is sufficient but two or more spline sections may be employed if sufficient space is available for the additional slots. For greater strength and durability, it is desirable to stagger the staves, as illustrated in FIGURE 4, whereby only one butt joint will `appear in any given length or" pipe cornprising, for example, la length corresponding to the division of the length of the staves by the number of staves employed in cross-section.

aoeaoao After the staves ld have been assembled into the described tubular base i2, encircling bands of stainless steel are tightly wound about longitudinally spaced apart portions thereof substantially throughout the length of the conduit. The staves are intentionally formed to a relatively thin section -by comparison with other insulated sections thereby to insure the transmission of cold to the stainless steel bands. Because of the higher coecient of contraction and expansion of stainless steel by comparison with the wood, the cold of the liquid will travel through the Wood to the bands whereby the latter will be caused to tighten about the staves to minimize the leakage under conditions of use. The bands will relax when the Iliquid ceases to flow through the conduit thereby to relieve the compression which is desirably induced into the staves in operation. Instead of stainless steel, the bands may be formed of other strips of metal which retain their ductility and strength at 'temperatures below 100 F., as represented by aluminum, alloys of aluminum, and austenitic steels, or the bands may be formed of tapes of unidirectional glass fiber impregnated with a resinous matenial.

The outer portion of the tubular base may be covered with suitable insulation material 22 to minimize heat loss into the liquid. Such external insulation may take the form of a highly porous, low density wood, such as balsa wood, ywhich may be formed into slabs and tacked onto the base. lt may comprise bats of glass or other mineral wool fibers wrapped about the tubular base or it may comprise sections of =honeycomb formed of resinous treated paper or corrugated veneer wrapped about the tubular base. In a preferred modification, illustrated in FGURES 1 and 2, use may be made of elongate ribs or fins 24 of wooden, plastic or laminated material fixed to the outer Wall of the tubular member 12 and bands 20 in circumferential-ly spaced apart relation. The ribs operate to strengthen and to stiffen the staves and the pipe section formed thereof and they operate, at the same time, to provide pockets 26, as hereinafter defined, into which particulate or other insulation 28 can be packed. Thus with the use of such ribs, the insulation Z8 arranged about the outer wall of the tubular base can be of such materials as perlite, granulated cork, exfoliated verrniculite, foamed glass, bloated clay, diatomaceous earth, as well as others of the insulation materials previously described. The ribs or fins will operate further as spacers to protect and to hold in place the insulation material and prevent compacting or displacement thereof.

When the ribbed construction is employed, it is desirable to make use of an outer skin 30 as a protective wrapping about the outside of the conduit. For this purpose, use can be made of a weather-resistant metal, such as aluminum or stainless steel, of relatively thin gauge which can be loosely wrapped about the pipe with little, if any, attachment either to the ribs or to the base thereby to avoid the difficulties of differential expansions and contractions. When a metal skin is employed, the meeting edges may be overlapped and joined into a standing seam as by welding or bracing to provide a complete enclosure to protect the conduit from Weather. Instead of a metal sheet, use can be made of pipe wrap in the form of asphalt treated paper, or plastic film stock or the `like to provide a self-sustaining sealed outer skin which operates in combination with the ribs to form the defined pockets 2.6 therebetween.

It will be apparent from the foregoing that the conduit which is produced in accordance with the practice of this invention is capable of being constructed on a mass production basis of materials which can be made readily available and prefabricated into sections for assembly. The combined elements provide for the rapid transmission of an extremely cold liquid therethrough with the sealing relationship to prevent leakage being increased in response to the temperature change effected upon contact by the liquid Since the wooden elements of which the conduit is formed have a very low coefficient of expansion and contraction, and since the wooden elements retain their ductility and compressibility throughout the temperature range to which they are exposed, it will be apparent that the wide temperature changes will have little, if any, harmful effect upon the elements of which the conduit is formed or upon its stability or durability in operation.

if desired, the inner surfaces of the tubular base may be heavily coated with a suitable resinous material for incre? ing the liquid impermeability whereby penetration of liquid through the wood will be greatly minimized. instead, the inner surfaces of the staves forming the tubular base may be lined with a plastic lm, with or without fibrous reinforcement or with a metallic film to enhance the impermeability to liquids.

lt will be understood that various changes may be made in the materials of which the conduit is formed and in the means and method of assembly, as Well as in the dimensional characteristics thereof, without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

l. A conduit `for the transmission of large volume of a liquefied natu-ral gas at about atmospheric pressure comprising elongate hardwood staves of relatively thin crosssection formed to lengths up to feet arranged in end-to-end and in side-by-side relation to form a pipe, the meeting end edge of said staves being staggered so that no more than one abutting edge between staves occurs in any one cross-section, longitudinally spaced apart bands of a metal capable of retaining its strength and ductility at the extremely low temperature of the liquid fitting tightly about the assembled staves, laterally spaced apart rib members fixed to the outer surfaces of the staves and extending lengthwise of the conduit, an outer wrap of weather-resistant material about the ribbed sections to provide an opening between the Wrap and the assembled staves with the opening being divided crosswise by the ribs into compartments, an insulating material of low thermal conductivity filling the space between lthe rib members, the inner surface of the outer wrap and the outer surface of the banded staves, the means interconnecting said staves comprising slots extending into the end and side edges of the staves in position to be aligned one with the others of the staves when arranged in end-to-end and in side-by-side relation, and splines formed with elongate wooden elements of thin cross-section extending crosswise between the adjacent edges of the staves and into the aligned slots for crosstying the staves one to the other for the transfer of load and effecting the assembled relation, whereby cold is transmitted through the staves to the metal bands and causes contraction thereof by an amount greater than the contraction of the staves under equivalent temperature change with resultant increase in the tightness of the metal bands about the assembled staves.

2. A conduit for the transmission of a liquid which needs to be maintained at a temperature differing widely from ambient temperature, comprising elongate staves arranged in end to end and in side by side relation to form a pipe, means joining the abutting edges of the staves in sealing relation, longitudinally spaced apart metal bands fitting tightly about the assembled staves, said metal bands being formed of a metal which is capable of retaining its strength and ductility at the temperature of the liquid, such staves being formed of a fluid and vapor impervious material which is resistant to attack by the liquid and maintains its ductility at the temperature of the liquid and which is of relatively thin crosssection whereby the cold of the liquid is transmitted through the staves to the metal bands to cause contraction thereof by an amount greater than the contraction of the staves under equivalent temperature change with resultant increase in the tightness of the metal bands about the assembled staves, laterally spaced apart rib members Xed to the outer surfaces of the staves and outwardly of the bands to extend lengthwise of the pipe, insulating material of 10W- thermal conductivity disposed about the outside of the banded staves and between the rib members, and an outer wrap of a weather resistant material encasing the staves, bands, ribs and insulation.

References Cited in the file of this patent UNITED STATES PATENTS Wiestling June 26, Allen Mar. 22, Marks Apr. 30, Kipp July 17, Gottwald et al. Oct. 5, Likely July 25, Colton Sept. 4, Scovronek Apr. 9,

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