US3446888A - Cryogenic tanks and process of making the same - Google Patents

Description

May 27, F X CROWLEY CRYOGENIC TANKS AND PROCESS OF MAKING THE SAME Filed June 19, 1967 Sheet of 2 INVENTOR.

FRANCIS X. CROWLEY BY May 27, 1969 F. x. CROWLEY 3,446,888

CRYOGENIC TANKS AND PROCESS OF MAKING THE SAME Filed June 19, 1967 Sheet 2 of 2 FIG. 5

INVENTOR; FRANCIS X. CROWLEY United States Patent 3,446,888 CRYOGENIC TANKS AND PROCESS OF MAKING THE SAME Francis X. Crowley,-Wellesley, Mass, assignor to Crowley Hession Engineers, Boston, Mass, a partnership Filed June 19, 1967, Ser. No. 646,975 Int. Cl. B28b 1/16; B29d 27/04; EMF) I/I6 US. Cl. 264-256 2 Claims ABSTRACT OF THE DISCLQSURE A cryogenic tank comprising an inner ply of sheet metal having spikes projecting therefrom at intervals, concentric plies of insulating material and concrete impaled on said spikes, and prestressed wire binding the assembled plies, together with process of making the same.

This invention comprises a new and improved cryogenic tank of the type designed to contain and store liquefied gases at extremely low temperatures and which consequently require massive and effective heat insulation.

I have discovered a novel process and structure by which such tanks may be constructed rapidly and at moderate cost and with outstanding advantages from the standpoint of thermal efiiciency. The structure may be defined as comprising an inner ply of sheet metal having spikes projecting therefrom at intervals, concentric plies of insulating material and of concrete impaled on the spikes, and prestressed wire binding the assembled plies.

More specifically the inner ply is of sheet steel forming a continuous metallic wall and having a pattern of spaced outwardly projecting metal spikes. A concentric insulating ply of styrofoam is impaled upon the spikes and a concentric ply of concrete is then cast upon the insulating ply so that it encloses the outer ends of the spikes. Having constructed panels of this character and of the proper shape for the contemplated tank the panels are assembled and bound under compression by prestressed wire protected by a covering ply.

The panel units may be produced advantageously in accordance with the process suggested to some extent in my copending application Ser. No. 589,650, filed Oct. 26, 1966. In carrying out the process of this invention a solid casting bed of concerte is first built up and provided with a curved upper mold surface. The bed is surrounded by upstanding boundary boards or frames forming a complete mold having the contour of the desired panel unit. A panel of sheet metal is conformed to the curved mold surface and provided with a pattern of outwardly projecting spikes. Upon these spikes is impaled a panel of styrofoam or other foamed synthetic resin. A concentric ply is now formed by casting a concrete panel upon the styrofoam panel thereby enclosing the ends of the spikes. These operations are then repeated, always conforming a new metal panel to the concrete ply of the previously completed unit.

I prefer to use styrofoam for the insulating component of the panel unit. This is polyethylene with its cells inflated with as much as 95% air by volume. It is a material of high thermal insulating value. It will not absorb water, is highly resistant to mold and decay and may be readily bonded to metal. Other foamed synthetic resins having similar characteristics may be employed within the scope of the invention.

The features and advantages of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof and the process of its construction as shown in the accompanying drawings in which:

FIG. 1 is a view in perspective of the frame used in construction of unit panels,

FIGS. 2, 3 and 4 are sectional views suggesting progressive steps of the process.

FIG. 5 is a similar view suggesting the construction of a second panel unit as it is formed in position upon a unit already completed, and

FIG. 6 is a fragmentary sectional view of a tank wall formed of the assembled and connected panels.

The unit panels for the tank may be advantageously prepared as indicated in FIGS. 1-4 where a bed 10 of concrete is first built up and provided with a curved upper mold surface. The bed is surrounded by upstanding boundary boards or a frame 11 forming with the bed a complete mold having the contour of the desired panel unit. The surface of the bed 10 is curved cylindrically by the conventional use of a screed 17 and the mold surface thus produced will later serve as a templet for successive panel units.

A sheet steel panel 12 is now conformed to the curved mold surface of the bed 10 and from this panel projects upwardly a pattern of spikes or pins 13. These are preferably also of steel and may be welded in place either before or after the panel 12 is in place. The panel may be in the order of one-fourth inch in thickness and the spikes 10 or 12 inches in length and spaced about two feet apart.

A second ply of the panel unit comprises a sheet or slab 15 of styrofoam or the like which is cut to size, impaled on the projecting spikes and so held in concentric position on the steel ply. The latter projects about six inches on all marginal edges beyond the styrofoam slab, thus leaving flanges that are exposed for the welding of adjacent units.

The third component of the unit is a concrete ply 16 which is cast upon the styrofoam slab 15 in such thickness as to enclosed the ends of the spikes 13 that project above the styrofoam slab. The spikes may be fitted with washers or knobs 14 to increase their hold on the cement. The concrete ply 16 is cast within the confines of the frame 11 as extended above the slab 15. This ply may be reinforced and prestressed in accordance with conventional procedure.

As soon as the concrete of the ply 16 has set, the boundary boards 11 are extended upwardly thus providing an overlying mold for a second composite panel which takes its shape from the panel already completed. This procedure is repeated until a stack is built up containing the required number of segmental tank units.

In assembling the unit panels to form the tank the exposed edges of the sheet steel plies are brought together and welded, as at 20 in FIG. 6. The openings or channels between the edges of the plies 15 and 16 are now completely filled with blocks or bars 15- and 16' of styrofoam and concrete. The assembly is then bound about with prestressing wire 18 and the tank completed by a facing coat 19 of cement. The styrofoam will transmit pressure up to psi. or more from the steel ply to the concrete, but may be actually compressed to some extent by action of the prestressing wire.

It will be apparent that the resulting tank is of high structural strength and capable of long life under the extreme variations of temperature to which it is subjected in use. Moreover its heat insulating characteristics are of unusually high order rendering its particularly 3 effective in the protection of low temperature contents. All these desirable properties are attained from a structure that may be erected with economy under convenient building conditions.

Having thus disclosed my invention what I claim as new and desire to secure by Letters Patent is:

1. The process of making cryogenic segmental tank units comprising the steps of forming a sheet metal panel with upwardly projecting spikes to a convex base form, impaling a styrofoarn sheet upon said spikes, casting a concentric concrete ply upon the styrofoam sheet and thereby enclosing the ends of the spikes and repeating the operation, always forming a new metal panel to the outer concrete ply of the previously completed unit.

2. The process of making cryogenic segmental tank units as described in claim 1, further characterized in that the styrofoam sheet overlies the metal panel in areas exposing marginal portions of the metal panel as flanges for welding adjacent units.

References Cited UNITED STATES PATENTS 2,656,902 10/1953 Gotshall S22 69 2,705,414 4/1955 Rose 52-245 2,969,544 1/1961 Di Marco et al 264-45 2,982,623 5/1961 Johnson 52249 3,106,227 10/1963 Crowley 52-224 3,151,416 10/1964 Eakin et al 52-249 FOREIGN PATENTS 1,050,346 6/1962 Great Britain.

HENRY C. SUTHERLAND, Primary Examiner.

I. L. RIDGILL, 111., Assistant Examiner.

US. Cl. X.R.

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