Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2532587 A
Publication typeGrant
Publication dateDec 5, 1950
Filing dateMar 4, 1946
Priority dateMar 4, 1946
Publication numberUS 2532587 A, US 2532587A, US-A-2532587, US2532587 A, US2532587A
InventorsWilliamson Thomas F M
Original AssigneeAlexander H Isenberg
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Thermal insulated pipe
US 2532587 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)


Patented Dec. 5, 1950 Thomas FQKM. Williamson, San Francisco, Calif.,

Lassignor to Alexander H. Isenbeg, Woodside,


Application 'Mofoh 4, 1946, serian No. `651,848


This invention relates to pipe which is` both lthermally insulated as well as insulatedor'sealed against water gaining access to thethermal insulation, andthe principal object of the inventin is to provide improvements in th'e'oonstructionof such pipe as well as improved steps in its making so that the resulting finished product will be more durable and efective for the purposes aboveset out. j Y

'Particular features and advantagesof the invention are'v set out inthe following description and in the 'following'drawings Y y Infthedrawing's Fig. 1 is a perspective view of a pair of metal pipes'e'nclos'ed in their heat and moisture insulating jackets and outer sheet metal casing made inaccordancewithmy invention.

Fig. 2 is aplan View of Fig. 1 shown partly in section. s n y Fig. 3 is a crosssection of Fig. 2 taken along the line 3--3 thereof.

s Fig. 4 is a cross section of Fig. 2 taken along the line 4-4 thereof and Vshowingthe pipe as seriiblag'e'supported within an aligning trough.

n Fig. A5` is aperspective view of a'single pipe assemblage with itsI tubular casing supported inuan aligning trough distorting its casing out of round. Y 6 is a fragmentary plan View showing va couple of the pouring or casting slotv closing plates invplace, and with a :modified joint sealing strip.

Fig, 7 is an'end View of 'a single pipe assemblage having an expansible casing. v y

Brief-ily described the finished product comprises one or more pipes enclosed in thermal covering vsuch as yasbestos or magnesiacomposition Steam pipe covering, spacedly supported within an outer casing (preferably of bendable non-rigid sheet metall, and with the Vspace between the lcasing v and the thermal s'teampipe covering iilled with pcurable moisture impervious pitch, tar, asphaltum, 'or mixture of these generally classed as bitumens introduced ina heated or molten condition and permitted to harden in th'ecasing when 'it cools. Such a product broadly vis old in the art as my invention relates to improvements which 'go'f'ar in meeting industrial requirements V"heretofore not satisfactorily met. n

In the drawings the pipe is designated i, the

'thermal covering 2, the spacing means 3, the 'moisture' impervious material such-as asphaltum 4, and outer casing 5, the latter being non-rigid Y'sheet material t0 provide a mold for the bitumen. f "I-Ieretof'ore the outer casings have always been round in vcross section Vand themolten'pitch has "eitherfbeen pouredl in at one end of the-assemblage Withth'e assembly tilted, or poured throughside openings or slots in the casing with uio assomoiy in horizontal position. In such assemblages vune solid asphalt pitch layer is generally about an inch thick and it expands andfcontract's With heat and cold, and to Such an extent that it has been customary to leave the pouring slots open to take care of the expansion to prevent fracture of the outer casing, and one of the objects of the 'present inventionis to take care of any such expansion orvcontractionwithout vrequiring' any open'- ing's in the casing, and which is effected by having the sheet metal casingother than of simple round cross section, say ofl oval, or Around and flattened on one or more places, for eample. and of de'- Yformable sheet metaLas distinguished from heavy load-"bearing pipe., so that in eXpanding the pitch Will forcethe casing walls outward toward a true round `cross section and hencetoward a larger vinternal capacity vto take (care of the increased volume, and upon shrinkagewith lowering ltemperature the casing will contract again toward its `original cross section. With the above eX- lplanation of one Vof the features of my invention `original round cross section (denoted by the' dotted circular line 8), and in Fig, '7 the casing 5" is shown as slightly corrugated to permit of eX- pansion'frominward pressure, and corresponding contraction when the pitch shrinks.

In Figs. g1, 3,v Lland 5, the casing is provided with a slot 9A or openings! 53 on' top through which to 'pour the molten pitch. In Figs, l, 3 and 4 vthe casing 5 is shown formed of sheet metal bent lto substantially oval form and with its two edges spaced to form the Slot 9 and with the edges bent outwardly to form hooks il running the length of the oasing, whi1e'in Fig. 5 the opening mayfbe oneorsev'eral slotted openings spaced along the casing, and each slot formed with outwardly hooked edges I2.

The spaced outwardly hooked edges l2 of Fig. 5 and I l of Figs. 1, 3 and ltare adapted toreceive cover plates i3 which are formed with confronting or inwardly turned hooked edges lll to engage over the hooked edges of the slot Sor pitch pouring openings lIl), asindicat'ed in Figs. l, 3 and 4. These cover plates may also be of sheet metal and preferably eachis provided with van' extending lip latone vend only which may loe-forced under 'al preceding plate I3 when several plates are used to cover a slot, and in which case the plates may be slid along from one or both ends of the casing to the position shown in Fig. 2 (right hand portion) Where the lip I5 is shown tucked below the adjacent or preceding plate, and the lip being preferably tapering as indicated in Fig. 2 so as to make a sealed joint when all are driven up tightly together, and after which the engaged edges of the plates and casing may all be flattened down substantially into the plane of the casing wall by striking them with a hammer, mallet, or flat heavy bar. It is to be understood that the asphalt or pitch layer l had rst been permitted to become firmly set. Instead of providing a lip l5, a separate piece of sheet metal may be positioned under each joint as at l5 in Fig. 6.

The casing is preferably formed of sheet metal and deformed from regular arc in transverse section, by making a succession of definite longitudinal or axial bends as with a sheet metal workers brake to form a series of successively adjoining longitudinally parallel flat surfaces I6 or narrow panels disposed arcuately and dened by angles or corners I1 which are obtusely angular and the vertex of which is radially outward relative to the axis of the enclosed pipes; or otherwise slightly fluted for the length of the casings as this insures the casings remaining straight or true and eliminates the tendency of the casings to warp and twist as they do if merely bent on a smooth curve.

As heretofore stated, since an arc or circle encloses greater area than other geometric form,

the providing of angles I1 of Fig. l, or corresponding corrugations 5" of Fig. 7, decreases the area filled by the pitch which, when the thermal expansion takes place, tends to restore the arc of a circle, and when the pitch again contracts upon cooling, the metal, due to having been bent beyond its limit of elasticity, seeks to return to its former shape, as so bent or angled. The bends vor angles Il as shown in Fig. 3 and the peaks of the corrugations as shown in Fig. 7 are of greater radial distance from the center of the casing and obviously have greater resistance to radial deformation than the areas therebetween, for the same reason that an angle iron has greater resistance to bending than a fiat strip. Therefore, it is the areas between the angles or ridges which expand and contract.

In making up the assemblage, the pipe or pipes I are first covered with the heat insulation material 2, and which is preferably lengths of the conventional magnesia steam pipe covering put over the pipe in split block sections and held in place as by a canvas wrapping 2 glued or cementled in place, the adjacent ends of the lengths of insulation material being relatively spaced, while at intervals along the pipes bare spaces are preferably provided in which are placed preformed firmer insulating blocks i3 as of asbestos-cement composition around which are spacing band devices 3 which space the interior of the outer cas- Hing about an inch from the outer surface of the f the insulation 2 applied to the pipe between the spaced blocks, but I prefer to make the blocks I8 in sections parted along the horizontal line I8 so that they may be applied after the pipe (or both pipes of Figs. 1 to 4) have been insulated at all other places, and the spacing band device 3 may be wrapped about the two block sections to firmly tie them and the pipes into a handling unit which is then placed into the casing 5 either by slipping the unit in endwise, or springing the casing open (if of the type shown in Figs. 1-4) and inserting it from above.

The spacer band 3 is preferably of metal, although it may be of plastic or other lower heat conducting material, and it may be formed in any numerous ways to provide a band portion 3 having circumferentially spaced outwardly projecting spacing lugs 3 so that the band may be tightly wrapped about the block sections I8 and the ends crimped in place as at I9. As best shown in Fig. 4, the spacing lugs space the outer casing from the insulation body around pipe I, the lugs being circumferentially spaced so that the pitch may flow therebetween longitudinally within the outer casing.

Before pouring in the molten asphalt, the assemblage is preferably placed level within a trough 6-'7 to align the casing and force the slot edges to parallelism so that a few of the cover plates I3 may more easily be applied while leaving suflicient of the slot open for pouring the molten asphalt or other waterproof filler to lill the space between the casing and the thermal insulation.

It is also desirable that the aligning trough be continuous for the full length of the assemblage and be provided with naked steam pipes 20 through which hot steam can be circulated from any suitable source, not shown, so as to keep the entire assemblage hot until the molten pitch is all poured.

Before pouring the pitch, the extreme ends of the casing space are closed either by suitable insulating filler blocks, although preferably by a putty of asbestos ber and/ or magnesia cement composition as has been common Ipractice in the art.

In pouring the molten pitch, particularly if of a normally solid grade of asphalt great trouble has been experienced in obtaining a complete filling of the space, and I have discovered that if the molten mass is poured in several stages, generally three will do, and a few minutes time is given between pourings to permit the previous one to gradually settle into all the interstices and the enmeshed air bells to break and pockets of air to escape, a completely solid ll may be produced, and as has heretofore been almost impossible to obtain.

After the casing is full and no more settling takes place, the stem heat is turned olf, and cooling water may be passed through pipes 23 if desired as well as sprayed over the top from a hose or special spray pipe, to entirely set the asphalt, and after which the entire slot may be closed with the interlocking cover plates and all hammered down in tightly interlocked condition with the casing edges.

Such an oval form of casing as shown in Figs. 1, 3 and 4 may be tightly sealed yet is able at all times to expand and contract to accommodate the requirements of the asphalt as explained previously in this description.

If a corrugated casing as shown at 5 in Fig. '7 is used the corrugated shell will of course be able to expand or contract as the filler may require. It is of course apparent that such a casing may contain but one or any number of the insulated pipes l, and also that the spacer blocks as at I8 in Fig. 4 and spacer band 3 would be shaped to suit However, the preferred form of casina is the bending in longitudinal ridges and iiat areas therebetween as shown in Figs. 1 to 4, as such form permits expandability and contraction at lower pressures and also is better adapted to use of the spacer member 3.

If itis desired to use a simple casing of plain round cross section and still gain the expansion and contraction advantages above described, it may be done as shown in Fig. 5 and wherein the dotted circle 8 indicates the original round cross section of the casing, but which was compressed or squeezed inward slightly at opposite Sides by being crowded into a rigid walled trough 'I of slightly less width inside than the original casing, so as to make the cross section of the casing slightly oval in a vertical direction as shown in the drawing. Such a conned easing will have a lesser inner area than the original round easing, and the molten asphalt may be poured in the space from the ends by tilting the trough and casing at a convenient angle, or poured through any number of openings on top such as the slots I0, or as is evident the slot may extend the full length as described for the casing of Fig. 1.

While I describe or imply the outer casings of the various modifications shown in the drawings to be of sheet metal, they may in some cases be of other sheet materials such as plastic, fiber, etc. when such materials are available with the characteristics required.

Also, since the waterproof filling may be of solid asphaltum, tar, pitch, or a mixture of these or other meltable water resisting compounds, my use of the word pitch in the claims is intended to embrace any of such materials or mixtures thereof.

Such insulated pipes as above described may be joined at their end to make any lengths desired as is well understood in the art, and they may be used for conveying either hot or cold liquids or gases for any purpose where ingress or egress of heat to or from the pipes is required to be overcome.

Having thus described my improvements in thermal insulated pipe, and the manner of its making what I claim is:

1, An insulated pipe comprising a conveyor pipe enclosed in thermal insulation and spacedly supported within an outer deformable tubular casing shell having an arcuate wall portion and a pourable filling of moisture impervious material in the space, said casing shell having in its arcuate wall portion a plurality of successively connected relatively angularly disposed flat areas arranged arcuately, said flat areas being non-rigid and axially longitudinal of and integral with the wall of the casing shell to provide for radial expansion of the filling, the angle vertex between said flat areas being radially outward relative to the longitudinal axis of the enclosed pipe.

2. An insulated pipe of the class described having the elements of claim 1 and in which the casing has a longitudinal pouring opening provided with longitudinal free edges which are spaced apart and outwardly hooked to receive a complementally hooked cover plate, and a sheet cover plate for closing said pouring opening, said cover plate having complementally hooked edges for engaging the hooked edges of the casing at the pouring opening, said cover plate comprising a plurality of sections in which one of the sections is provided with a tongue extending from a free end thereof and adapted to overlap the adjacent end of an adjacent section of cover plate.

3. An insulated pipe comprising a conveyor pipe member enclosed in thermal insulation and spacedly supported within an outer non-rigid deformable tubular casing shell having an arcuate circumferential wall portion, said shell being provided with an opening for receiving a pourable filling, a bitumen filling of moisture impervious filling in said space between insulation and shell, said casing shell having in its arcuate wall portion a plurality of integral successively connected relatively angularly disposed flat areas arranged arcuately, said flat areas being axially longitudinal of the wall of the casing shellthe angle vertex between said flat areas being radially outward relative to the longitudinal axis of the enclosed pipe.

v4. An insulated pipe of the class described having the elements of claim 3 and in which spacer means are interposed between the thermal insulation and the outer casing shell, said spacer means comprising bands snugly circumferential of the thermal insulation and relatively spaced longitudinally thereof and said bands having thereon circumferentially spaced lugs extending radially outwardly from the band to the outer casing shell, the circumferential spacing of the lugs permitting fluid bitumen to flow longitudinally past the spacer means between the thermal insulation and the outer casing.

5. An insulated pipe of the class described having the elements of claim 3 and in which the adjoining longitudinal at areas of the casing are relatively connected at longitudinal edges by obtuse angles.


REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 360,782 Ober Apr. 5, 1887 1,297,047 Wallace Mar. 11, 1919 1,709,844 Durant Apr. 23, 1929 1,797,443 Powell Mar. 24, 1931 2,041,911 Ericson May 26, 1936 2,068,180 Horsman Jan. 19, 1937 2,243,427 Kleifel May 27, 1941 2,324,181 Tulen July 13, 1943 2,330,966 Gottwald et al. Oct. 5, 1943 2,405,021 Durant July 30, 1946 FOREIGN PATENTS Number Country Date 319,004 Great Britain Sept. 4, 1929

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US360782 *Apr 5, 1887 Covering for steam pipes
US1297047 *Jul 20, 1918Mar 11, 1919John W WallaceMeans and method of uniting the margins of flexible materials.
US1709844 *Jul 12, 1927Apr 23, 1929Durant Albert AInsulated pipe
US1797443 *Aug 24, 1928Mar 24, 1931Banner Rock CorpMonolithic underground insulation
US2041911 *May 25, 1935May 26, 1936Universal Insulation CompanyHeat insulation
US2068180 *Oct 23, 1935Jan 19, 1937William H HorsmanInsulating material and method of applying and sealing the same
US2243427 *Jun 18, 1938May 27, 1941Harrison E KleffelTube covering
US2324181 *Sep 11, 1940Jul 13, 1943Johns ManvillePipe covering
US2330966 *Sep 18, 1939Oct 5, 1943Ric Wil CompanyFluid distribution system
US2405021 *Jun 7, 1944Jul 30, 1946Durant Albert AInsulated pipe
GB319004A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2650180 *Jul 5, 1951Aug 25, 1953Stanley F WalkerInsulating device for pipes, faucets, and the like
US2773513 *Dec 22, 1953Dec 11, 1956Isenberg Alexander HSubterranean insulated conduit unit having spacer channel between pipes
US2805972 *Jul 17, 1950Sep 10, 1957Kansas City Testing LabPipe lines and sheathing material therefor
US2807563 *Jul 5, 1952Sep 24, 1957Donald D GrassickInsulated pipe covering
US2817485 *Sep 21, 1953Dec 24, 1957Shepard Co LewisPallets
US2872946 *Jun 20, 1955Feb 10, 1959Stueber Harry KThermal insulation system
US2892441 *Feb 12, 1951Jun 30, 1959Dick E StearnsApparatus for coating elongated member
US2901775 *Sep 7, 1954Sep 1, 1959Zonolite CompanyMethod of insulating pipe
US2903017 *Feb 12, 1958Sep 8, 1959R W Mfg CoPipe support
US2915802 *Nov 6, 1953Dec 8, 1959Higgins IncMethod of making expanded cellular cement products
US2923650 *Mar 22, 1956Feb 2, 1960Jean SemeMethod of and device for heat-insulating piping for the long-distance conveyance of heating fluids
US2980568 *Jan 12, 1956Apr 18, 1961Constantine A KazmierowiczPlastic pipe covering
US3155117 *Nov 21, 1960Nov 3, 1964Escher Wyss AgDouble-walled hollow body for the reception of a hot gaseous medium under pressure
US3157204 *Oct 19, 1960Nov 17, 1964Morris T PhillipsInsulating and protective covering devices
US3244388 *Jan 20, 1964Apr 5, 1966Coffman Jack WInsulated pipe hanger construction
US3313321 *May 10, 1963Apr 11, 1967Rensulate CorpInsulated underground conduit
US3402731 *Aug 11, 1965Sep 24, 1968American Standard IncPiping systems
US3934615 *Apr 8, 1974Jan 27, 1976Paul LukomskyjSegmented rigid insulated conduit
US3980262 *Mar 9, 1972Sep 14, 1976Rilco, Division Sadler Industrial Services, Inc.Pipe insulation load bearing support
US4148341 *May 16, 1977Apr 10, 1979Granges Nyby AbLong-distance heating conduit
US4679600 *Sep 9, 1985Jul 14, 1987Durodyne, Inc.High tensile strength removable hose covering
US4737210 *May 7, 1987Apr 12, 1988Durodyne, Inc.Method of fabrication of high tensile strength removable hose covering
DE966070C *Feb 10, 1953Jul 4, 1957Wrede & Niedecken GmbhBlechmantel fuer waermeisolierte Rohrleitungen
EP1180635A2 *Aug 1, 2001Feb 20, 2002E. Missel GmbH & Co.Damping material for pipes
EP1213527A2 *Dec 4, 2001Jun 12, 2002Roland BaumannDevice for the insulation of multiple pipes
U.S. Classification138/149, 138/151, 249/90, 248/73, 138/148
International ClassificationF16L59/12, F16L59/00, F16L59/15, F16L59/14
Cooperative ClassificationF16L59/12, F16L59/15, F16L59/14
European ClassificationF16L59/12, F16L59/15, F16L59/14