US3026577A

US3026577A - Means and method for mounting prefabricated panels of insulation

Info

Publication number: US3026577A
Application number: US743630A
Authority: US
Inventors: Cornelius D Dosker
Original assignee: Conch International Methane Ltd
Current assignee: Conch International Methane Ltd
Priority date: 1958-06-23
Filing date: 1958-06-23
Publication date: 1962-03-27
Anticipated expiration: 1979-03-27

Description

March 27, 1962 c. D. DOSKER MEANS AND METHOD FOR MOUNTING PREFABRICATED PANELS OF INSULATION Filed June 23, 1958 INVENTOR. CorndzuJD. DOSkCI 3,026,577 MEANS AND METHOD FOR MOUNTING IRE- FABRICATED PANELS F INSULATIUN Cornelius l). Dosker, Louisville, Ky., assignor, by mesne assignments, to Conch international Methane Limited, Nassau, Bahamas, a corporation of the Bahamas Filed June 23, 1958, Ser. No. 743,630 1 Claim. (Cl. 20-4) This invention relates to the storage and/or transportation of a cold boiling liquefied gas and it relates more particularly to the method and means for the fabrication of an insulated space wherein the liquefied gas can be housed during storage and transportation to minimize heat loss into the liquid which might otherwise cause excessive vaporization.

The invention can be described with reference to the storage or transportation of liquefied natural gas. However, the concepts can also be employed for the storage and transpmtation of other gases which needs to be maintained at extremely low temperature, such, for example, as liquefied air, liquefied nitrogen, liquefied helium and the like.

Storage and transportation of liquefied natural gas is of particular interest because liquefaction of the natural gas enables the gas to be reduced in volume about 600 times to enable economical transportation of the gas from a source of plentiful supply to an area where a deficiency exists, where the liquefied gas can be reconverted to the gaseous state for use.

From the practical standpoint, it is desirable to provide for storage and transportation of the liquefied gas in large volume and at atmospheric pressure or slightly above. This requires the liquefied natural gas to be maintained at or below its boiling point, which, in the case of liquefied natural gas, normally composed mostly of methane, is at a temperature within the range of 240 F. 'to 2S0 F. depending somewhat upon the amount of heavier carbons present in the gas.

In order to minimize heat loss from the ambient atmosphere into liquefied gas, it is desirable to house the liquefied gas in a well-insulated space. One such construction is described in my co-pending application, Serial No. 646,001, filed March 14, 1957, and entitled Heat Insulated Wall and Tank Construction. As described in this application, insulating panels of substantial di mension are mounted on a supporting Wall to define an insulated space in which liquid storage tanks of substantial capacity are positioned. The panels are prefabricated for separate assembly on to the supporting walls to provide a continuous insulating layer between the tanks and the ambient atmosphere on the other side of the supporting wall, and the panels are of substantial thickness to provide for sufiicient insulation to be effective in reducing the amount of liquid loss by evaporation.

A number of specific problems arise by reason of the wide temperature differential between the liquefied natural gas in the storage tanks and the ambient atmosphere, because of the thickness and dimension of the prefabricated insulation panels which are substantially indepentently mounted on the supporting wall so that one face of the panel will be at or about the temperature of the liquefied natural gas while the other or outer face of the panel will be at or about ambient temperature.

It is an object of this invention to provide a simple and efiicient means for mounting the prefabricated insulation panels on the supporting wall to provide an insulated tates ate ti 3,@2fi,5 77 Patented Mar. 27, l9fi2 space for the storage of a liquefied gas or other material which needs to be maintained at extremely low temperature, and it is a related object to provide a means for resiliently supporting the panels on the wall in a manner to permit differential contractions and expansions between inner sections of the panel and outer sections of the panel without destruction of the panel or support and without interference with the storage or transportation of the liquid carrying tanks housed within the insulated space.

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 1 is a perspective elevational view of a prefabricated insulation panel of the type employed in the build-up of the insulated space;

FIGURE 2 is a sectional elevational view through the panel in mounted relation on the wall to illustrate the ar rangement of parts by which the mounting is effected; and

FIGURE 3 is a perspective elevational view of an insulated hold section of a ship in which liquid carrying tanks are positioned for storage and transportation.

The invention will be described with reference to the insulation of a hold space 10 of a ship 12 for the use of the ship in the transporation of large tanks 14 carrying liquefied natural gas 16 over a body of water from a source of plentiful supply, where the gas is liquefied and loaded into the ships tanks, to an area where a deficiency exists where the liquefied natural gas is revaporized for use. It will be apparent that the same concepts of insulation and assembly can be employed to insulate any confined space for the land storage of the liquefied gas or for the storage of any other material which needs to be maintained at extremely low temperature.

The spaces insulated by the use of panels 20 are in the form of a unitary structure, having a relatively thick layer of insulation 22 faced on its outer wall with a panel of plywood 24 or other structurally strong material and preferably also faced on its inner wall with a panel of plywood 26. Instead of making use of a plywood panel 26, the insulation may be faced or otherwise lined with one or more metal foils or sheets, reinforced plastic sheets, or combinations of metal and wood or plastics built up into a desirable laminated structure. The panels 20 can be prefabricated into sections of substantial dimension, such as 4 x 8 sections, or even 8' x 8 sections. with the largest dimension capable of being handled being preferred because of the larger area capable of being covered by each of the panels in assembly. The panels 20 are formed to thicknesses of from 10" to 25" depending somewhat upon the type of insulation material employed and the amount of insulation that is required. The insulation section 22 can be formed of a low density wood, such as balsa wood, or of a honeycombed structure formed of paper or Wooden or plastic veneers, or the like insulating material, but it is preferred to make use of slabs or sections 23 having mass integrity and structural strength so that all of the elements of the panel can be carried by the plywood face 24 by wmch the panel is attached to the supporting wall 30, as will hereinafter be described.

Such panels can be prefabricated on a mass production basis at a facility separate and apart from the supporting wall to enable the wall to be lined with the insulation merely by attachment of the panels to the wall 30. Thus, one of the main objectives has been to develop a simple and efiicient means for securing the panels ztl into the desired relation onto the supporting wall 30 substantially completely and uniformly to cover the wall with insulation material.

For this purpose, the panels are each formed with a plurality of spaced apart openings 32 extending continuously from the inner face 34 to the outer face 36 of the panels, with the opening 38 through the outer plywood section 24 being of smaller dimension than the remainder. In the illustrated modification shown in FIGURE 1, six such openings 32 are provided. The number of openings can be varied depending upon the dimension of the panels and the strength characteristics of the elements thereof. It is desirable, however, to make use of more than one opening to provide support for the panel in at least two spaced apart points.

After a panel has been properly located on the wall 30 from the standpoint of adjacent panels and with reference to the wall, a Nelson stud 40 is inserted from the inside through an opening 32 for attachment to the wall portion 30 in endwise alignment with the opening so that the stud which is fixed to the wall by welding will extend for a substantial distance into the opening 32. Assembly can be completed by placing a washer 42 on the stud in which the washer is of smaller dimension than any portion of the opening 32 but larger than the opening 38 through the plywood panel 24. Thereafter a nut member 44 can be tightened down onto the threaded end portion of the stud, into engagement with the washer to draw the elements onto the wall with suflicient tension to hold the plywood panel firmly onto the Wall. Such means for attachment can be effected through each of the openings to provide multiple points of support for independently mounting each of the panels on the supporting Wall. The remainder of the openings beyond the stud can be filled by the insertion of a fitted plug of thermal insulating material and the space between adjacent panels can also be insulated and further provided with expansion joints as described in the aforementioned co-pending application in the build up of the insulated space.

The foregoing method of attachment of the panels represents one of the important concepts of this invention. Another concept resides in a means whereby a resiliency is built up into the assembly to enable differential expansions and contractions to take place in the panels in cross section without the build up of forces which might otherwise cause deformation of the -supporting walls or the separation or breakdown of components of the insulation panel. It will be apparent that the front face of the panel, which is next to the liquid carrying tanks, will ordinarily be at or near the extremely cold temperature of the liquefied cargo, While the outer portion of the panel will be at or near ambient temperature. Thus, a differential of about 350 F. will be caused to be developed through the cross section of the insulation panel in use with the result that the inner section of the panel will tend to contract to more than the outer section. Such differences in contraction between the inner and outer sections of the panel can cause the development of forces sufficient to tear the panel apart or otherwise cause deterioration of the panel or elements associated therewith, unless formed of exceptionally strong material.

This problem has been alleviated in accordance with the practice of this invention, by permitting the panels to cup as the inner portions contract by an amount greater than the outer portions without loss in the support or separation of parts of the panel. For this purpose, attachment is effected in the manner described but instead of tightening the nut member down onto the stud rigidly, to secure the panel to the supporting wall, a relatively thick gasket 46 or insert formed of a resilient or rubberlike material is inserted on the plug between the washer 42 and the nut member 44. The desired pressure is achieved by tightening down onto the gasket and washer while still permitting flexibility in the gasket for movement to enable the panel to cup in response to contraction forces built up Within the panel thereby to provide the necessary give without causing separation of parts or loss of the assembled relation.

In practice, the washer 42 is first placed upon the stud 40 and against the inner face of the plywood panel 24. A gasket 46 of about /2" to 2" in length and having a diameter corresponding to that of the Washer 42, is inserted onto the plug 40* and then another washer 48, similar to the first, is placed onto the stud to embrace the gasket therebetween. A nut member 44 is threaded onto the end of the stud and tightened down to the desired pressure, such as 1,000 lb. The nut is preferably located in position by means of a lock nut 56 to effect the as sembled relation. Thereafter, a plug (not shown) is inserted to block the opening 32 and insulate the space.

The resilient gasket 46 may be formed of natural or synthetic elastomeric materials or of plastic materials having a substantial degree of compressibility or flexibility to enable slight movement of the plywood panel 24 relative to the stud subsequent to effecting the assembled relation thereby to enable the plywood panel 24 to shift inwardly in compliance with the forces developed in the panel due to contraction. Thus, when the inner portion of the panel contracts more than the outer por tion, the insulation panel can move onto the studs by an amount to permit the natural cupping of the panel. Ordinarily movement in the order of a small fraction of an inch is all that is required even for panels of 18 or 16 lengths or widths. Such movement is permitted with a force far less than that capable of being withstood by the panel so that no breakdown or separation will take place.

It will be apparent that I have described a simple and efiicient means whereby prefabricated insulation panels of substantial dimension may be easily and quickly mounted upon a supporting wall to provide an insulated space. It will be apparent further that I have provided means in the mounting for introducing a flexibility which enables the panels to respond to the natural forces developed in use without the existence of resistances within the panel which would necessitate the breakdown or separation of elements thereof.

It will be understood that changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention especially as defined in the following claim.

I claim:

A wall mounting comprising the combination of a supporting wall and insulating panels mounted on the supporting wall, said insulating panels comprising a composite of a relatively thick layer of a relatively soft thermal insulating material and an outer face ply of a relatively hard structurally strong material on the side adjacent the supporting wall, openings extending continuously crosswise through the panel and with the opening through the face ply being of smaller dimension than the remainder of the opening through the panel, a threaded stud secured at its outer end to the supporting wall and extending from the supporting wall part way through said panel openings, nut means threadably received on the stud portion extending into the opening, and an abutment between the nut means and the face ply dimensioned to be larger than the opening through the face ply but smaller than the remainder of the opening through the panel, a resilient spacer of substantial thickness interposed between the nut member and the face ply to enable axial movement of the face ply relative to the nut member responsive to expansion and contraction forces developed in the panel for movement relative to the wall without noticeable increase in the force holding the panel onto the supporting wall, said nut means being turned down onto the stud to bring the abutment into pressing engagement with the face ply to hold the panel onto the sup- References Cited in the file of this patent UNITED STATES PATENTS Crecca June 9, 1942 6 Trader Sept. 15, 1925 Woodson May 3, 1927 Welch Ian. 9, 1940 Zeidler Aug. 10, 1943 Donnelly Oct. 14, 1958 Potchen May 26, 1959