US3543002A

US3543002A - Quartz heater pack

Info

Publication number: US3543002A
Application number: US706830A
Authority: US
Inventors: Richard R Poole
Original assignee: MILLETRON Inc
Current assignee: MILLETRON Inc
Priority date: 1968-02-20
Filing date: 1968-02-20
Publication date: 1970-11-24
Anticipated expiration: 1987-11-24

Description

Nov. 24, 1970 R. R. POOLE 3,543,002

QUARTZ HEATER PACK Filed Feb. 20, 1968 3 Sheets-Sheet 1 Nov.24, 1970 R. R. POOLE QUARTZ HEATER PACK 3 Sheets-Sheet 2 Filed Feb. 20, 1968 Nov. 24, 1970 R. R. POOLE QUARTZ HEATER PACK 5 Sheets-Sheet 5 Filed Feb. 20, 1968 United States Patent 3,543,002 QUARTZ HEATER PACK Richard R. Poole, Norwalk, Conn., assignor, by mesne assignments, to Milletron Incorporated, Pittsburgh, Pa, a corporation of Pennsylvania Filed Feb. 20, 1968, Ser. No. 706,830 Int. Cl. Hb 3/44 US. Cl. 219-354 8 Claims ABSTRACT OF THE DISCLOSURE A high intensity quartz heater pack capable of use as a module for radiant heating of hollow process rolls. The heater pack comprises several parallel quartz tubes assembled in touching contact between a pair of ceramic end caps. A unitary coiled electrical resistance wire passes from tube to tube by way of a groove in the ceramic end caps. The resistance wire is constructed of variable relative pitch so that more radiant heat is emitted from the tube ends and outside tubes than from the central portion of the middle tubes.

This invention relates to a high intensity heat radiation unit and more particularly to a quartz heater pack constructed to provide a substantial radiant heat output from a relatively small unit.

The usual quartz infra-red heating lamp consists essentially of a resistance wire heating element, appropriate electrical connections to the heating element and a surrounding quartz envelope or tube. Typically, the quartz tube is mounted in ceramic end caps through which the electrical connections pass, the caps serving as the structural support means to mount the quartz heater in its desired position for operation as a heating element.

Where the radiant heat requirements are substantially more than can be supplied by a single quartz lamp, multiple quartz heaters are mounted on a single support. On occasion, heat requirements are so substantial and the spacing allowance so minimal that provision of sufiicient heating capability within an allowed-for space becomes difiicult. Such a practical necessity for closely associated quartz heater lamps may lead to a high failure rate for the heater wires, terminal leads, even the mounting struc' ture, because close lamp spacing imposes an elevated temperature environment on the quartz heaters themselves. The heating problem is particularly severe in the short process rolls employed in the textile arts to handle synthetic fibers.

'Copending application Ser. No. 475,206, filed July 27, 1965, now Pat. No. 3,369,106, granted Feb. 13, 1968, by John H. Troll discloses a particularly advantageous roll heating and control system involving use of an infrared emitter to heat a thin-walled hollow process roll. Application of the heating and control system to short, relatively small diameter process rolls requires an infrared heating element which must emit substantial quantitles of energy from within the quite small volume inside the process roll. A subsidiary problem is that a quartz heater expressly suitable for a particular short process roll would be a product of limited sales potential because process rolls used in the textile arts come in a great many diameters and lengths. To some extent heater length can be adjusted by simply extending the length of the quartz tube and heater wire but the same is not true for roll diameter since the number of quartz heaters which may be placed inside the roll depends upon the roll diameter. A quartz heater pack module capable of assembly into diverse multi-pack configurations would be a desirable product.

Patented Nov. 24, 19

Accordingly, the object of the present invention is to provide a high intensity quartz heater pack.

A further object of this invention is to provide a quartz heater pack capable of module use to assemble many different sizes of process roll heaters.

Still another object of this invention is to provide a quartz heater pack capable of rapid installation and removal.

Further objects and the advantages of the present invention will be apparent from the description thereof which follows.

Now in accordance with the present invention it has been found that these and other objects can be realized by providing a quartz heater pack having a pair of ceramic end caps along with a plurality of quartz tubes assembled side by side between the ceramic end caps and in such a manner that they touch and form a single layer which may be planar or slightly curved. Further in accordance with the present invention the ceramic end caps have disposed therein elongated closed end grooves. The length of the groove disposed within the end cap is substantially equal to the sum of the diameters of the combined plurality of the quartz tubes and the width of the groove is substantially equal to the individual diameter of the tubes. Each of the ceramic end caps is also provided with a shallow elongated recess in the base of the elongated groove, which recess defines a shoulder against which the ends of the tubes, which are seated in the grooves, rest. A unitary resistance wire heating element is disposed inside each of the quartz tubes and the shallow recess in the end cap serves to provide passage of this wire from one tube to the next.

Reference is now made to the attached drawings wherem:

FIG. FIG. in FIG.

FIG. FIG. 1.

FIG.

1 is a plan view of a heater pack. 2 is a side elevation of the heater pack shown 1. 3 is an end view of the heater pack shown in 4 is a section taken along line 44 of FIG. 2. 5 is a section taken along line 55 of FIG. 2. 6 is a section taken along line 6-6 of FIG. 2. 7 is a section taken along line 77 of FIG. 2.

FIG. 8 is an enlarged partial section taken along line 8-8 of FIG. 1.

FIG. 9 is an end View and partial section of a roll heated by an assembly of six heater packs.

FIG. 10 is a section of the heated roll taken along line 1010 of FIG. 9.

As may be seen in the drawings the heater pack 10 of the present invention contains a pair of ceramic end caps 12 and a multiplicity of quartz tubes 14. A pair of metal (stainless steel) support rods 16 pass beneath tubes 14 and through the end caps 12. Retaining rings 18 of the external gripping ring type secure the end caps 12, quartz tubes 14 and support rods 16.

In a preferred embodiment as is illustrated in the drawing, one end of support rods 16 are attached to a stop plate 20, the plate being spaced apart from end cap 12. In turn, stop plate 20 is provided with some suitable at tachment means element such as socket head screws 22 for mounting the heater pack 10 in its heating position, as is shown in FIGS. 9, 10. If desired, support rods 16 may each have a threaded end which extends beyond stop plate 20 so that the support rods 16 can be used for mounting purposes. In any event, stop plate 20 is spaced apart from the nearest end cap 12 enough to allow introduction of a power lead 24 therebetween. The spacing gap keeps stop plate 20 from overheating.

A reflector 26 (which may be stainless steel) underlies quartz tubes 14 being interposed between the tubes and the rods 16. If desired, a layer 28 of insulation material is placed on reflector 26. Reflector 26 terminates in a tab which extends through an aperture in end cap 12, the tab being bent over as shown in FIG. 4.

Each end cap 12 contains a deep elongated groove or slot 30 in which quartz tubes 14 fit. At the base of groove 30 in a shallow recess 32. Groove 30 and recess 32 create a shoulder 34 at the peripehry of recess 32, the quartz tubes 14 actually resting on shoulder 34, as is shown best in FIG. 8. Desirably the electrical resistance wire 40 forming the heating element extends from one tube 14, into recess 32 and from there into the next adjacent tube to make electrical connection between adjacent quartz tubes thereby, shown in FIGS. 7, 8. Groove 30 is closely sized tubes 14 so that the tubes fit tightly inside grooves 30 in a straight or slightly curved configuration as is shown in the drawings. Ideally, quartz tubes 14 are in complete touching contact one with the other. Heater pack 10 is sized for at least two tubes and in a preferred mode four of the quartz tubes 14.

As shown best in FIG. 4, the power leads 24 for heater pack 10 enter and leave the same end cap 12 by way of apertures 38, drilled in the end cap which is adjacent stop plate 20. In a preferred connection between power lead 24 and resistance heating wire 40 as illustrated in FIG. 7 of the drawings, the resistance wire 40, the end of lead 24 and a barrel lug 42 are are welded together. Suitably, barrel lug 42 is of nickel or stainless steel. In practice, this electrical connection has been found to be effective and relatively trouble free.

The electrical resistance wire 40, which is the heating element, may be a single coil of wire extending in zigzag fashion through all of quartz tubes 14 in the heater pack, as is shown in FIG. 7. The coil is deformed just enough at the end of each tube 14 to allow a relatively straight wire segment to extend from the end of one tube 14 into recess 32 then back into the next adjacent tube 14. Since the wire zig-zags back and forth, tube to tube, from its starting connection at one power lead 24 to its terminus connection at the other power lead 24, use of an even number of quartz tubes 14 in heater pack 10 (e.g., four) is what permits both power leads 24 to connect through the same end cap 12. I

An important aspet of the present invention resides in the close, i.e., touching, physical relation of quartz tubes 14 in heater pack 10. Such close spacing must however take into account certain thermal considerations which exist for the heater pack 10 as a whole. More heat can be radiated away from the outer tubes 14 than from the inside tubes. Also, more heat may be needed by the roll ends than the center of the roll. Therefore, if resistance wire coil were of uniform relative pitch (relative pitch being the ratio of the distance between the centers of adjacent coil convolutions and the diameter of the wire), then the equilibrium temperature of the central portions of the inside tubes would be far above the temperature of the outside tubes adjacent end caps 12. In compensation, a preferred practice according to the present invention is to increase the relative pitch 20%70% in the central tubes. Thus, the outer tubes might employ a relative pitch of 1 and the inner tubes a relative pitch of 1.2. In effect, the outer tubes become heated more than the inner tubes, but then again they can radiate away the increased heat energy. Also contemplated is a lengthwise non-uniformity in pitch. Thus, the wire coils may have the pitch of 1 only at the ends of the outer quartz tubes, with a central portion pitch at 1.1. The inner tubes coils have then an end region pitch of 1.2 and a central portion pitch 1.4. FIG. 7 illustrates, in somewhat exaggerated form, the relative pitch differences between the inside quartz tubes 14 and the outside tubes.

The drawing further illustrates another important feature of construction, namely the rounded off shape of the side surfaces or edges 36 of each end cap 12. As shown in FIGS. 4, side surface 36 curves inward toward both the top and base ends of the end cap. Presence of curved side surfaces 36 on end caps 12 permits assembly of a multiplicity of heater packs 10 into a generally cylindrical configuration such as shown in FIG. 9, with the confiuration having for example 4, 6, 8 or 10 heater packs, the actual number employed depending on the size of the process roll. FIGS. 9 and 10 illustrate a six pack assembly. Thus, a substantial amount of custom design may be done using the heater pack 10 as a module. Moreover, quartz tubes 14 and stainless steel rods 16 are available in running lengths and normally would be cut to any desired size and still fit end caps 12. Therefore, the only custom work actually involved in fitting heater packs to different length and diameter rolls is in adjusting the relative pitch and the bend of the coil for passage from tube to tube. The present quartz heater pack is therefore adapted both for mass production and at the same time for custom use in many different sized process rolls employed by the fiber industry.

FIGS. 9 and 10 illustrate how six heater packs may be mounted inside a hollow process roll to heat same. The roll is secured by nut 102 to the end of a rotatable shaft 104 which passes through a stationary Wall 106. For assembly or disassembly, the nut 102 is removed and roll 100 slipped off shaft 104. The stop plates 20 may then be secured to wall 106 by threaded members 22. The remainder of heater pack 10 is a pre-assembled unit consisting of end caps 12, tubes 14, reflective shield 26 and of course the power leads 24 attached to resistance wire 40. After pre-assembly of these members the tab ends of shield 26 are bent to hold the pre-assembly together so that it may be shipped and installed as a unit. The unit is slipped onto rods 16 and releasably attached by retainer rings 18 to complete the assembly. As illustrated in FIG. 9, l0 suitable apertures are provided in wall 106 for power leads 24 to pass through. Thus the detailed construction of the present heater pack provides for rapid installation and for rapid replacement of worn units. Rapidity of replacement parts is particularly important, since the down time of the process rolls and its associated equipment may be far more expensive than the heater pack replacements.

While particular embodiments of the invention have been illustrated and described, it will be obvious that changes and modifications may be made without departing from the invention and it is intended to cover in the appended claims all such modifications and equivalents as fall within the true spirit and scope of this invention.

What is claimed is:

1. A quartz heater pack comprising a pair of ceramic end caps, a plurality of quartz tubes assembled in a single layer in side by side touching contact, said tubes being disposed between said ceramic end caps, each said end cap having therein an elongated closed end groove, the width of the groove being substantially equal to the diameter of the tubes and the length of the groove being substantially equal to the sum of the diameters of the plurality of the tubes, the ends of said tubes being seated in said grooves, each said cap also having a shallow elongated recess in the base of the elongated groove, said recess defining a shoulder against which the ends of the tubes rest and a continuous resistance Wire heating element disposed inside said tubes, said shallow recess serving for passage of said wire from one quartz tube to the next, and means joining said end caps and tubes to gether into a unitary heated pack.

2. A quartz heater pack as in claim 1 wherein said joining means comprises a pair of metal rods extending through said end caps which are detachably attached thereto, and wherein a stop plate to which said rods are fixedly mounted is spaced apart from one of the end caps.

3. A quartz heater pack as in claim 1 wherein said resistance wire heater element is coiled and wherein the coiled element has a non-uniform pitch With the relative pitch at the central portion of the tubes being greater than adjacent the tube ends.

4. A quartz heater pack as in claim 1 containing in excess of two quartz tubes in touching contact and wherein the resistance wire heating element is in the form of a coil with non-uniform pitch, the relative pitch inside the outer tubes being less than that inside the central tubes.

5. A quartz heater pack as in claim 4 wherein a lengthwise non-uniformity of the relative pitch exists, with the relative pitch centrally of each tube being greater than the relative pitch adjacent the tube ends.

6. A quartz heater pack as in claim 1 wherein said joining means includes a heat reflective shield adjacent said tubes, said shield extending at each end through a slot in each ceramic end cap to terminate in a bent over tab, said shield serving thereby to join said tubes and end caps into a unitary assembly.

7. A quartz heater pack as in claim 1 wherein an even number of quartz tubes are in the pack and wherein one end cap contains apertures therethrough for introduction of electrical leads to the terminal ends of said resistance wire heating element.

8. A quartz heater pack as in claim 1 wherein the side elges of said end caps are rounded whereby a multiplicity of said heater packs may be closely grouped in diverse cylindrical configurations containing a different number of heater packs.

References Cited UNITED STATES PATENTS 25,532 9/1859 Simpson 338-286 998,269 7/1911 Trepreau 219-353 1,014,437 1/1912 Bastian 219-537 X 1,040,043 10/1912 Smith 338-319 X 1,276,096 8/1918 Moftat 338-290 X 1,548,305 8/1925 Dalton 338-232 3,237,144 2/1966 Joeckel 219-553 X 3,307,017 2/1967 Horstmann 219-553 871,153 11/1907 Wicker 219-354 2,369,803 2/1945 Sardeson 219-354 3,171,945 3/1965 Meng 219-357 X FOREIGN PATENTS 832,929 7/1938 France. 1,488,820 6/1967 France.

213,855 6/1941 Switzerland.

503,203 3/1939 Great Britain.

ANTHONY BART IS, Primary Examiner US. Cl. X.R.