US3393297A - Combined heating and insulating means for heat-treating objects - Google Patents

Description

-TREA'IING OBJECTS O. M. HART July. 16, 1968 COMBINED HEATING AND INSULATING MEANS FOR HEAT 2 Sheets-Sheet 1 Filed Jan. 14, 1966 ATTORNEYS 0. M. HART July 16, 1968 COMBINED HEATING AND INSULATING MEANS FOR HEAT-TREATING OBJECTS 2 Sheets-Sheet 2 Filed Jan. 14, 1966 INVENTOR Oliver- M fikwi JZ AJW I M ATTORNEY$ United States Patent 1 3,393,297 COMBINED HEATING AND ENSULATHNG MEANS FOR HEAT-TREATING OBJECTS Oliver M. Hart, (Cornwall Bridge, Conn. @6754 Filed Jan. 14, 1966, Ser. No. 529,626 5 Claims. (Cl. 219-528) ABSTRACT OF THE DISCLQSURE A self-contained unit is provided for operation at temperatures in excess of 1500 F. A flexible body means includes flexible insulation means at an outer face thereof, and pocket defining means at the inner face thereof for removably receiving electrical heating means therewithin. The materials employed are adapted to withstand temperatures in excess of 1500 F. and the pocket defining means is of flexible relatively thin open construction and formed of a good head conductor material to provide efiicient heat transfer from the heating means to an article adjacent the inner face of the body means.

The present invention relates to a new and novel combined heating and insulating means for heat-treating objects, and more particularly to a selt-contained unit for heat-treating metallic elements.

The unit of the present invention is particularly useful for stress relieving pipes or similar welding objects wherein stresses are ordinarily set up during a welding operation. Heating of such elements up to certain specific temperatures is a common practice, and the present invention provides a very effective means for heat-treating such objects.

A common procedure for heat-treating similar objects is to employ a hand-held gas torch for heating the object and then wrapping insulating material around the object to be heated. In other cases resistance heating elements have been applied to the object, requiring the services of skilled electricians, whereupon insulating material is wrapped around the object being heat-treated. These types of procedures are quite time-consuming, and further require the services of skilled laborers, thereby making the procedure quite expensive.

Typical stress relieving temperatures may be, for example, in the range of approximately 2000 R, and the present invention provides a combined heating and insulating self-contained unit wherein resistance heating means is provided for affording the desired stress-relieving temperature, and wherein the unit also includes outwardly of the heating means an insulating means which cuts down the heat loss and which maintains a substantially uniform temperature while the object is being heat-treated.

The unit of the present invention is specifically designed so as to provide a flexible construction permitting its use with objects of different size and shape. In other words, the flexible body means of the present invention can be wrapped around or disposed in complementary relationship to various types of objects.

It is particularly suitable, for example, in stress relieving of pipes wherein the body means may be wrapped completely around the pipe.

A further important advantage of the present invention is that the apparatus may be readily mounted by unskilled labor in a substantially fool-proof manner in substantially less time than is required to carry out similar procedures with prior art techniques. The present invention affords a very simple and inexpensive construction for this purpose, while at the same time providing a very eflicient and reliable arrangement which is also quite durable.

333,297 Patented July 16, 1968 The overall arrangement is such that the insulation means is disposed at one side of the body means to provide the most effective insulation at the outer portion of the apparatus, and the heating means is disposed at the opposite side of the body means and is so constructed and arranged that the heat generated by the heating means may be most efiiciently transferred to an object to be heattreated and supported inwardly thereof.

An additional improved feature of the present invention is the arrangement wherein the heating means comprises a plurality of separate individual heating units, each of which is removably supported by the body means of the apparatus, whereby the individual heating units may be readily removed and repaired or replaced, as the case may be. In this manner, if one particular portion of the heating means should become damaged or ineffective, it is not necessary to remove the complete heating means from the unit, but only the particular heating unit which is defective.

An object of the present invention is to provide a combined heating and insulating self-contained unit including both the heating and insulating means required for heat-treating welding objects and which substantially reduces the heat losses and maintains a uniform temperature during the stress-relieving operation.

Another object of the invention is the provision of a combined heating and insulating self-contained unit of flexible construction, which permits its use with objects of different size and shape and which may be readily iounted by relatively unskilled labor and in a substantially fool-proof manner in less time than required for carrying out similar prior art operations.

A further object of the invention is to provide a combined heating and insulating self-contained unit wherein portions of the heating means are removable for easy repair and maintenance as required.

Still another object of the invention is the provision of a combined heating and insulating self-contained unit which is quite simple and inexpensive in construction, and yet which is very efficient and reliable in use and further which is quite durable.

Other objects and many attendant advantages of the invention will become more apparent when considered in connection with the specification and accompanying drawings, wherein:

FIG. 1 is a top perspective view illustrating the unit of the present invention in operative relationship about a p p FIG. 2 is a top view of the inner face of the body means when the apparatus is in its unfolded flat position;

FIG. 3 is a top perspective View on an enlarged scale and partly broken away, illustrating the attaching means of the unit;

FIG. 4 is a sectional view taken substantially along line 4,-4 of FIG. 2 looking in the direction of the arrows;

FIG. 5 is a View taken substantially along line 55 of FIG. 4 looking in the direction of the arrows;

FIG. 6 is a sectional view taken substantially along line 6-6 of FIG. 5 looking in the direction of the arrows; and

FIG. 7 is a top view of a modified form of a heating unit according to the present invention.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, FIG. 1 illustrates the unit of the present invention indicated generally by reference numeral 10 as being wrapped around a pipe 12 which is to be heattreated. As seen most clearly in FIGS. 2-6, the body means of the present invention includes a retainer means which may be of an open construction such as wire mesh or the like, this retainer means including a first sheet of 3 material which is folded over to provide upper and lower layers 14 and 16 respectively. The opposite free edges of this sheet of material are suitably secured to one another as by spot welding at spaced points 18 along the adjacent edges when the sheet has been folded and the edges placed in proximity to one another.

In a similar manner, the opposite end edges of the sheet of material are spot welded at spaced points therealong as indicated by reference numerals 20 and 22 respectively to thereby provide an enclosed space within the sheet of grid-like material.

A body of insulating material indicated by reference numeral 24 is disposed within the enclosed space provided within the aforementioned sheet of material, this body of insulating material being snugly received within the retainer means. The thermal insulating material comprises a substantially continuous fiat homogeneous body formed of flexible material and is adapted to provide good insulation at high temperatures. A refractory type insulation of inorganic nature may be employed such as ceramic fibers and the like.

As seen most clearly in FIGS. 1 and 2 four spaced attaching means are secured to the body means, and as illustrated in FIG. 1, suitable means such as wires 32 are adapted to be laced around these attaching means for securing the apparatus in operative position.

Referring particularly to FIG. 3, the details of construction of one of the attaching means is illustrated, it being understood that all of the attaching means are of similar construction. An attaching member indicated generally by reference numeral 34 includes a hook-like portion 36 formed of two adjacent portions of an elongated tubular member bent upon itself, the member 34 including a pair of relatively straight leg portions 38 which are turned outwardly away from one another as indicated at 40. The portions 38 and 40 rest upon the upper surface of a disc-like member 42, and a U-shaped connecting member 44 is disposed in overlying relationship to the upper surfaces of portions 38 and extends downwardly through suitable openings provided in member 42.

' The U-shaped member 44 extends downwardly through the body of insulating material 24 and through suitable openings provided in a lower disc-like member 46 similar to member 42. The lower ends of U-shaped member 44 extend outwardly and are turned upwardly as indicated at 48 about the outer periphery of the lower disc 46. It will be noted that members 42 and 46 are disposed immediately outwardly of and in contact with the portions 14 and 16 of the retainer means respectively and the entire attaching means assembly is held in proper fixed relationship with respect to the body means due to the clamping action of disc members 42 and 46 which are drawn toward one another by the U-shaped connecting member 44.

As seen particularly in FIG. 2, a first pocket means is formed by providing a sheet 50 of wire mesh or similar open material which is spot welded at spaced points along the opposite edges thereof as indicated by reference numerals 52 and 54, and one end of sheet 50 is spot welded at spaced points as indicated by reference numeral 56. It will be understood that sheet 50 is spot welded to the lower layer 16 of the retainer means, and that the provision of the spot welds along the various edges of sheet 50 will provide a pocket means closed on three sides and which is open at the upper edge 58 thereof as seen in FIG. 2. This provides a pocket for receiving a heating unit hereinafter described.

A second pocket is provided by a sheet 60 similar to sheet 50, sheet 60 being spot-welded along one edge thereof by the same spot welds 54 that secure the adjacent edge of sheet 50 in place. The opposite side edge of sheet 60 is spot-welded at spaced points as indicated by reference numeral 62, and the lower edge of sheet 60 as seen in FIG. 2 is spot-welded at spaced points 64.

The upper edge 68 of the pocket defined by sheet 60 4 is unsecured to the adjacent layer 16 of the retainer means, thereby providing an open end to the pocket along the upper edge thereof as seen in FIG. 2 for receiving a sec ond separate heating unit.

A third pocket is formed by a sheet 70 which is spotwelded along one edge thereof by the same spot welds 62 employed for spot-welding the adjacent edge of sheet 60. The opposite side edge of sheet 70 is spot-welded at spaced points as indicated by reference numerals 72, while the lower edge portion of sheet 76) is spot-welded at spaced points as indicated by reference numerals 74. The pocket defined by sheet '70 is open at one end thereof adjacent the upper edge 76 as seen in FIG. 2 for receiving a still further separate heating unit as hereinafter described.

Three similar but completely separate and independent heating units are indicated generally by reference numerals 8% as seen in FIG. 2, these heating units each being disposed in one of the three separate pockets provided at the inner side of the body means. It is apparent that the body means will be disposed adjacent an object to be heat-treated such that the heating means 80' are disposed closely adjacent the object whereby the pocket side of the body means comprises the inner side or face of the body means, while the opposite side of the body means including the body of insulating material defines the outer side or face of the body means. It should also be noted that the heating units are separated from the body to be heat-treated only by the thin sheet of wire mesh of members 50, 60 and 70 so that the heat may be readily transferred from the heating unit to the object to be heattreated, the wire mesh of members 50, 60 and 70 preferably being of a good heat-conductive characteristic so that the heat will be efficiently transferred.

Each of the heating units 80 is provided with lead means 82 extending outwardly of the associated pocket, these lead means being connected with suitable coupling elements 84 which may in turn be connected with a cooperating coupling means operatively associated with a source of electrical energy. The lead means 82 is of sufficient length to permit the coupling means 84 to be readily positioned for connection to other suitable coupling elements.

Referring now particularly to FIGS. 5 and 6, the details of construction of one of the heating units 80 may be seen, it being understood that all of the heating units are of substantially identical construction.

The heating unit may comprise a flexible woven arrangement including warp members 86 of flat ribbon-like construction disposed in spaced parallel relationship to one another. These warp members are formed of a suitable metallic substance of good thermal conductivity to assist in transferring and dissipating heat from the resistance element hereinafter described. The ends of warp members 86 are suitably secured to a side member 88 at one end thereof, it being understood that a similar side member will be disposed at the opposite ends of warp members 86 to retain them in the desired operative position. The side members 88 may be of any suitable construction and may comprise members interwoven with the warp members if desired.

The woof of the woven heating unit comprises an elongated flexible resistance element 90, which may comprise a central resistance component 92 of nichrome wire or the like which may be multistrand for flexibility, this central conductor being surrounded by a layer of insulating material 94 of an alumina-silica ceramic fiber or the like, the insulating material in turn being covered by a wire braid 96 which physically protects the woof member and aids in heat dissipation. The woof member is interwoven with the warp members 86 so as to follow a tortuous path and to provide a large area of resistance wire in a particular area, the opposite ends of Woof member 90 being indicated by references 90 and 90" in FIG.

5, and these opposite end. portions extending outwardly and forming the lead portions 82 previously described.

. Referring nowto FIG. 7, a modification of the present invention is illustrated wherein the heating unit is of a slightly different construction. As seen in this figure, which is a top view of theheating unit, an upper layer 100 of wire mesh or the like is illustrated, itbeing understood that a substantially identical layer is disposed immediately therebeneath, and an electrical resistance element 102 is sandwiched between these two layers. Resistance element 102 may be substantially identical with the resistance element 90 previously described and includes opposite end portions 102 and 102" which may form the leads to the heating unit.

The two similar layers of wire mesh or the like are spot-welded to one another along the edge portions thereof as indicated at 104, and additional spot welds 6 are provided between adjacent courses of the tortuously disposed resistance element 102, whereby the resistance element may be maintained in its desired operative position by the various spot welds provided between the two layers of material which serve to sandwich the resistance element.

This heating unit as disclosed in FIG. 7 may be inserted into and removed from the pockets of the body means in the same manner as the heating units 80 previously described.

While the single unit according to the present invention is illustrated as wrapped around a pipe in FIG. 1, it should be understood that if a pipe of larger diameter should be provided, a plurality of such units may be suitably interconnected with one another by lacing them together with wires or to the attaching means thereof so that pipes of larger circumference may also be surrounded with these units. Additionally, if it is desired to Wrap a greater portion of the pipe extending in a longitudinal direction, a plurality of units may be placed side by side and suitably interlaced with one another. It will be apparent that by so interlacing a number of units, larger objects of unusual configuration may be readily covered with and surrounded by the units according to the present invention.

It is apparent from the foregoing that there is provided according to the present invention a new and novel combined heating and insulating means for heat-treating objects which comprises a self-contained unit including both a heating means and an insulating means for cutting down heat loss and maintaining a substantially uniform temperature for carrying out a heat-treating operation.

The over-all arrangement of the present invention provides a flexible construction which permits use thereof with objects of dilferent size and shape, and the apparatus may be readily mounted in operative position by relatively unskilled labor in a fool-proof manner and in less time than required with prior art procedures. A plurality of individual heating units are provided, these heating units being supported within pockets which permit the heating units to be readily removed and repaired or re placed as required. While the pockets and heating units have been shown as being three in number, it is apparent that any number of heating units may be employed as desired. The apparatus is quite simple and inexpensive in construction and yet at the same time is quite efiicient and reliable in use and very durable.

As this invention may be embodied in several forms Without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

What is claimed is:

1. A combined heating and insulating self-contained unit comprising a flexible body means, said body means including a retainer means of wire mesh, said retainer means including attaching means secured thereto for re taining the body means in operative position relative to an object to be heat-treated, said retainer means defining a first space within which is disposed a body of thermal insulating material, said body of thermal insulating material being substantially continuous and homogeneous throughout and being disposed at one side of said body means, said retainer means also defining a plurality of spaced pockets at the opposite side of said body means, each of said pockets being open at one end thereof, a heating unit removably disposed within each of said pockets and including electrical lead means extending outwardly of said pockets, each of said heating units comprising a flexible woven heating unit including a warp of flat ribbon-like members of good thermal conductivity and including a woof of electrical resistance wire covered with insulating material and surrounded with a wire wrap to protect the resistance wire and the insulating material and to provide good heat dissipation therefrom.

2. A combined heating and insulating self-contained unit comprising a flexible body means including retainer means, said retainer means being of open construction, a body of thermal insulating material supported within said retainer means at one side of said body means, said retainer means including means for removably supporting heating means at the opposite side of said body means and adjacent to said body of thermal insulating material, said heating means comprising a pair of layers of Wire mesh, and an electrical resistance element sandwiched between said layers of Wire mesh and electrically insulated therefrom, said layers of wire mesh being suitably secured to one another for retaining the electrical resistance element in operative position therebetween.

3. A combined heating and insulating self-contained unit comprising a flexible body means, attaching means for retaining said body means in operative position relative to an object to be heat-treated, said body means including retainer means of open grid-like construction, a substantially continuous and homogeneous body of thermal insulating material being supported within said retainer means at one side of said body means, said retainer means defining at the opposite side of said body means a plurality of spaced pockets, each of which is open at one end thereof, a plurality of separate independent heating units, each of Which is removably disposed within one of said pockets, whereby the heating units can be readily removed as desired, each of said heating units including an electrical resistance element, and means associated with said electrical resistance element and in contact therewith for retaining the electrical resistance element in the desired configuration and for assisting in good heat transfer from said electrical resistance element to an adjacent object to be heat-treated, said means in contact with said electrical resistance element comprising a plurality of flat ribbonlike members of good thermal conductivity woven between various portions of said electrical resistance element.

4. A combined heating and insulating self-contained unit for heating articles to high temperatures in excess of 1500" F. for extended periods of time comprising, flexible body means adapted to be placed adjacent articles of different size and configuration, said body means including flexible retainer means defining a space therewithin, insulating means disposed Within said space and supported by said retainer means, said insulation means comprising a flexible body of thermal insulating material, said thermal insulating material retaining its thermal insulating qualities and characteristics at temperatures in excess of 1500 F said thermal insulating material being disposed at one side of said body means which defines an outer face of the body means adapted to face outwardly when the body means is in operative position, the opposite side of said body means defining an inner face, and pocket defining means at the inner face of said body means, said pocket defining means being of flexible relatively thin open construction and being formed of a material which is a good heat conductor and which is adapted to withstand high temperatures, electrical heating means supported within the pocket defined by said pocket defining means, said electrical heating means including lead means for connection to an external source of electrical energy and also including electrical insulation means for electrically insulating said heating means, said electrical insulation means retaining its electrical insulating qualities and characteristics at temperatures in excess of 1500 B, said pocket being open at a portion thereof to permit ready insertion and removal of the heating means with respect to the pocket, whereby the heating means is supported adjacent the inner face of said body means, and the open construction of said pocket defining means permits ready and efficient heat transfer from said heating means to an object disposed adjacent the inner face of said body means.

5. A combined heating and insulating self-contained unit as defined in claim 4 wherein said electrical heating means includes a plurality of flat ribbon-like members of References Cited UNITED STATES PATENTS 2,162,021 6/1939 Kidwell.

2,482,665 9/1949 Geyer 219535 X 2,572,695 10/1951 Briscoe et al 219-535 2,584,302 2/1952 Stein 219 527 2,607,876 8/1952 Bergen et a1. 219--535 X 2,697,775 12/1954 Licht 219212 2,889,445 6/1959 Wolf 219-345 3,144,545 8/1964 Shrimplin et al 219-213 3,178,560 4/1965 Mapp et a1. 219--528 3,272,968 9/1966 Volker 219-535 RICHARD M. WOOD, Primary Examiner.

V. Y. MAYEWSKY, Examiner.

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