US2982932A - Flexible heating tape - Google Patents

Description

May 2, 1961 G. H. MoREY 2,982,932

FLEXIBLE HEATING'TAPE Filed April 13, 1959 if i 48 2 23 26 INVENTOR.

FLEXIBLE HEATING TAPE Glen H. Morey, Terre Haute, Ind., assigner, by mesne assignments, to Templeton Coal Company, Inc., Terre Haute, Ind., a corporation of Indiana Filed Apr. 13, 1959, Ser. No. 806,020

8 Claims. (Cl. 338-212) This invention relates to electrical heating tapes and is by way of being a continuation-impart application of my copending application Serial No. 752,812, tiledv August 5, 1958, entitled Electric Heating Tape and Method of Making and assigned to the same assignee as the instant application.

In the co-pending application referred to above there is shown a flexible electric heating tape characterized in that the heating element -is in the form of a flat ribbon with an insulating sheath surrounding the ribbon consisting of woven or braided textile material that is resistant to heat. Such material might co'mprise, for example, high temperature glass, asbestos or quartz.

A particular advantage of a heating element of the type referred to having a ribbon-like heating element is that the element itself can operate at a lower temperature than in conventional heating tapes where the heating element is in the form of a ltine wire. There is better distribution' of heat, the heating tape has longer life because the heating element will withstand more abuse than a fine wire4 heating element, and the size limitations that ordinarily accompany flexible heating tapes are substantially eliminated.

In o'ne form of the flexible heating tape illustrated in my co-pending application l show an arrangement wherein a return wire runs from one end ofthe heating tape back to the other end so that both terminals of the heating tape are at one end rather than having one terminal at each end as is usually the case. The placing of both terminals at one end of the tape is of advantage for making electrical connections to the tape. Also, when the tape is disconnected it is completely de-energized whereas with connection at each end it may be necessary to disconnect both ends of the tape to make certain that it is not connected to an energized line.

The provision of a return wire in such a heating tape where the wire is in the form of a simple conductor, introduces problems in :connection with adequately insulating the return wire in View of the temperature conditions that prevail when the heating tape is in operation, and also, the conductor is substantially thicker than the ribbon-like heating elements and this tends to make the tape bulky. This condition becomes more aggravated when the length of the tape increases in order to provide an adequate return path for the electric current.

`l-laving the foregoing in mind, it is an object of this invention to provide an improved electric heating tape in which all electrical connections are made at one end thereof but in which the bulky expensive return wire usually employed is eliminated.

A still further object of this invention is the provision of a flexible heating tape having all electric connections made at one end thereof which can be of substantially any length and width combinations.

A still further object of this invention is the provision of a heating tape having a ribbon-like heating element therein which has all electrical connections made at one ite States Patent @ffice p 2,982,932 Patented May 2, 1961 nections are made at one end only of the tape in which the tape can be stressed longitudinally without imposing any substantial loads on the heating element within the tape or on :the electrical `connections at the end thereof.

These and other objects and advantages will become more apparent upon reference to the drawings in which:

Figure l is a view showing a tape according to the present invention mounted about a drum;

Figure 2 is a broken away perspective View showing the tape according to the present invention;

Figure 3 is a cross sectional view through the tape adjacent one end thereof as indicated by line 3--3 on Figure 2;

Figure 4 is a sectional View indicated by line 4-4 on Figure 2;

Figure 5 is a sectional View indicated by line 5 5 on Figure 3;

Figure 6 is a View showing one manner in which the end turn of the heating lelement at the end opposite the electrical connection with the tape can be made;

Figure 7 is a fragmentary perspective View showing the use of a magnet for clamping the end of the tape when it is mounted about or on a magnetic member; and

Figure 8 is a diagrammatic sectional View showing tie manner in which the end turn of the heating element can be accomplished by brazing or welding the. heating element portion together.

Refer-ring to the drawings somewhat more in detail, in Figure l there is illustrated a drum or like container it) which it is desired to heat. Such a drum might contain tar or other material to be maintained at a predetermined temperature.

Wrapped around the drum is a heating tape i2 according to this invention which terminates at its lower end in a plug 14 that is attached to a receptacle 16 on the end of a cord 1S which is adapted for being plugged into a source of electrical energy.

The heating tape according to the present invention is of novel construction which will be best seen in Figures 2 through 6. The heating tape is characterized in having a ribbon-like heating element and in order to avoid making connections at both ends of the tape, or utilizing a bulky return wire, the present invention employs two ribbon-like heating elements in side by side relation with the element joined at one end and at the other end fastened to individual connectors which may be embodied in a single electric plug.

Referring to Figures 2 through 6, the individual ribbon-like heating element portions are indicated at 20 and 22. These portions are individually sheathed by sheaths 24 and 26 which are woven or braided textile material which is preferably made up of asbestos or quartz bers but may consist of high temperature glass where the operating temperatures of the tape do not exceed a predetermined amount.

The heating element portions 2t) and 22 with their respective sheaths 24 and 26 'are coated with a rubberlike coating 2S which may advantageously comprise silicone rubber or another plastic which is resistant to high temperature.

Such a coating permits the heating tape to be employed in locations where moisture or the like would be apt to get on the tape and penetrate the sheath.

When such a coating is employed, the temperature of the heating element is limited to about 500 F. or so, this being determined by the exact nature of the coating and impregnating material. ln other cases where the tape is to be operatedv at high temperatures and ytemperatures up to as much as 2000 F. are to be attained, the sheathing would be without a coating or impregnant.

The two portions of the heating element and the sheaths are then brought into side by side relation with an intervening cord 30 and then the cord and the two sheaths on the opposite sides thereof are joined by a tape 32 adhesively connected therewith as by an adhesive which may comprise the same material as is used for coating sheaths. The tape is preferably a woven or braided member made up of quartz, asbestos or glass fiber.

The fabricated tape may then be coated with the coating and impregnating material if so desired or the entire Vcoating operation can be carried out after connecting tape 32 has been applied.

The connecting tape 32 and the cord 30 add considerable tensile strength to the heating tape as well as supporting the two sides of the tape'in spaced electrically isolated relation.

The tape as described can be manufactured in substantially continuous lengths and reeled and thereafter, in making up individual heating tapes, the proper length of the dual tape is taken from the reel and after the length desired is cut oit, the ends of the tapeV are bared and interconnected at one end of the tape and a plug or individual connectors are attached to the two ends of the heating element at the opposite end.

In Figure 2, the two portions 20 and 22 of the ribbonlike heating element are interconnected at 34 and this connection may be by way of rivets 36 as indicated in Figure 6 or by brazing or welding as at 3S as indicated in Figure 8.

A good connection between the two portions of the heating element by overlapping the ends of the heating element prevents there being a hot spot at the end of the tape. At their other ends the individual portions 20 and 22 of the heating element have connector members 40 -attached thereto to which are connected wires 42 that may lead to individual connectors such as banana plugs or to the terminals of a plug 44 which may advantageously have locking type terminals 46 thereon.

The opposite ends of the tape thus fabricated are provided with rubber-like members 4S which can be cemented in place as by cement 50. The rubber-like member 48 at the connector end of the tape has an aperture through which the wires 42 extend, and at the other end of the tape there is a wire or like member 52 extending through the corresponding aperture in the end of the rubber-like member 48 and being knotted at 54 inside of the member or attached therein to bar 56 or the like, and externally of the rubber-like member 48 wire 52 may be knotted or attached to a button or the like 58.

According to this invention the wires 42 and the wire 52 advantageously can be employed for supporting the heating tape onv a member such as a drum l by utilizing magnet elements 6i) which, as will Vbe seen in Figure 7 may comprise Alnico elements 62 supported between legs 64 so that the magnet can be set in bridging relation to the aforementioned wires and thus hold the tape in positionron any magnetic member.

By the present invention, a heating tape is provided having the particular advantages that all electrical connections can be made at one end, which is extremely thin and at, and which' can be made highly flexible when a fabric sheath is employed and which can be water-proof and of substantially any length and width depending on the voltage of the available power supply and the power (wattage) it is desired to expend. Y

In addition to the glass, asbestos and quartz referred to, synthetic bers such as Fiberfrax can be employed and; also individual yarns or threads making up the textile sheath could be reinforced by tine wire of linconel or stainless steel if so desired.

These elements would be employed with larger tapes and where the tapes might be subjected to considerable abuse.

Conceivably a dual heating tape according to the present invention could be constructed with a substantial rigid sheath as by placing the insulated dual tape within a metallic sheath as shown in my co-pending application, Serial No. 759,652, filed September 8, 1958, now Patent No. 2,939,099, entitled Metal Clad Heating Strip and Ribbon Element.

The same advantages relative to making the electrical connection at one end of the tape and eliminating the bulky return wire would obtain.

It is accordingly to beV understood that it is desired to comprehend such a modification of the present invention within the purview of'this application.'

It will be understood that this invention is susceptible to modification in order to adapt it to diterent usages and conditions; and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

1. In a new article of manufacture; an electric heating tape comprising a pair of thin straight metallic ribbonlike resistance heating elements of uniform width and thickness from end to end arranged in spaced side-by-side relation, a tubular sheath of high temperature resistant electrical insulating material closely surrounding each element, said elements being electrically interconnected at one end and having individual electric terminals connected therewith at their other ends, means connecting the said sheaths together in side by side relation to form a thin flat unitary tape, and insulator members mounted on opposite-ends of the tape enclosing the ends of said elements, said insulator elements comprising sleeve-like members extending along and connected to said sheaths, there being leads extending from the ends of said elements tothe aforementioned electric terminals through the end of one of said sleeves, and the other of the sleeves being adapted Vfor being connected to an object to be heated to support the tape thereon.

2. As a new article of manufacture; a pair of thin straight metallic ribbon-like resistance heating elements Y of uniform width and thickness from end to end arranged in spaced parallel side-by-side relation, a tubular sheath of heat resistant electrical insulating material closely surrounding each element, a spacer element in the space between the sheaths, a strip of material interconnecting the sheaths and spacer elements in side by'side relation to form a thin flat unitary tape, said heating elementsY being electrically interconnected at one end and having individual electric tenninals at their other ends, sleeve` like means mounted on the tape at the opposite ends thereof enclosing and insulating the ends of the heating elements, said sleeve-like means extending part way along the said sheaths and being connected thereto, and wires extending into the sleeve-like means at the said other end of said elements connected to said terminals for supplying electrical energy to said heating elements.

3. As a new article of manufacture, an elongated flexible electric heating tape comprising; a pair of thin straight metallic ribbon-like resistance heating elements of uniform width and thickness from end to end arranged in closely spaced parallel side-by-side relation, tubular sheaths surrounding said heating elements comprising heat resistant electrical insulating textile material, said heating elements being electrically interconnected at their one ends and having individual electric terminals at their other ends, a spacer member of insulating material in the space between said sheaths of about the same thickness as the sheathed elements, a strip of exible material interconnecting the sheaths and spacer member in side by side relation to form a thin'at unitary tape, and means enclosing and insulating thev ends of the elements at opposite ends of the heating tape, said means comprising annabee 'S sleeve-like members extending part Way along and connected to said sheaths.

4. As a new article of manufacture, an elongated iiexible electric heating tape comprising; a pair of ribbonlike sheathed resistance heating elements in closely spaced parallel side-by-side relation, each resistance heating element being a thin straight metal ribbon of uniform width and thickness from end to end, said sheaths comprising tubes of heat resistant electrical insulating textile material surrounding said heating elements, said heating elements being electrically interconnected at their one ends and having individual electric terminals at their other ends, a cord-like member in the space between said sheaths, a strip of ilexible material interconnecting the sheaths and cord, and means enclosing and insulating the ends of the elements at opposite ends of the heating tape, said last mentioned means comprising rubber-like sleeve elements adhesively connected with the tape at opposite ends, and the sleeve at one end of the tape having means for attaching the tape to an article to be heated, and there being leads extending from the ends of the heating elements at the other end of the tape through the end of the said sleeve to the said electric terminals.

5. As a new article of manufacture, an elongated flexible electric heating tape comprising; a pair of ribbonlike sheathed resistance heating elements in closely spaced parallel side-by-side relation, each resistance heating element being a thin straight metal ribbon of uniform width and thickness from end to end, said sheaths comprising tubes of heat resistant electrical insulating textile material sulrounding said heating elements, said heating elements being electrically interconnected at their one ends and having individual electric terminals at their other ends, a cord-like member in the space between said sheaths, a strip of flexible material interconnecting the sheaths and cord, and means enclosing and insulating the ends of the elements at opposite ends of the heating tape, said last mentioned means comprising rubber-like sleeve elements adhesively connected with the tape at opposite ends, and the sleeve at one end of the tape having means for attaching the tape to an article to be heated, and there being leads extending from the ends of the heating elements at the other end of the tape through the end of the said sleeve to the said electric terminals, the tape being coated and impregnated with a heat resistant plastic material.

6. As a new article of manufacture, an elongated exible electric heating tape comprising; a pair of ribbonlike sheathed resistance heating elements in closely spaced parallel side-by-side relation, each resistance heating element being a thin straight metal ribbon of uniform width and thickness om end to end, said sheaths comprising tubes of heat resistant electrical insulating textile material surrounding said heating elements, said heating elements being electrically interconnected at their one ends and having individual electric terminals at their other ends, a cord-like member in the space between said sheaths, a strip of flexible material interconnecting the sheaths and cord, and means enclosing and insulating the ends of the elements at opposite ends of the heating tape, said last mentioned means comprising rubber-like sleeve elements adhesively connected with the tape at opposite ends, and the sleeve at one end of the tape having means for attaching the tape to an article to be heated, and there being leads extending from the ends of the heating elements at the other end ofthe tape through the end of the said sleeve to the said electric terminals, the tape being coated and impregnated with a heat resistant silicone rubber material.

7. In a flexible heating tape. an elongated U-shaped resistance heating element, said element being relatively wide and thin in cross-Section, sheathing of a high temperature resistant electrical insulating material enclosing the element, individual terminals on the ends of the heating element, and means for attaching the heating tape to an object to be heated thereby, said means comprising U-shaped magnets which will attach to magnetic material, one of said magnets being adapted for being placed across the leads leading from the ends of the heating element to the electric terminals attached thereto and there being a connector member extending from the opposite end of the tape which the other magnet is adapted for engaging.

8. In combination, an elongated flexible electric heating tape, exible leads leading from one end of the tape and an electric plug to which the leads are attached, a cord-like member extending from the other end of the tape having an enlarged end part, and U-shaped magnets adapted for being placed about the leads and the cordlike member for attaching the tape to a magnetic member which is to be heated thereby.

References Cited in the le of this patent UNITED STATES PATENTS 1,155,167 Rose Sept. 28, 1915 1,384,467 Homan Iuly 12, 1921 2,559,077 Johnson et al. July 3, 1951 2,563,952 Nichol Aug. 14, 1951 2,584,302 Stein Feb. 5, 1952 2,585,443 COX Feb. 12, 1952 2,610,286 Cox Sept. 9, 1952 2,732,479 Rowland Jan. 24, 1956

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