US3400893A

US3400893A - Apparatus for forming glass fiber products

Info

Publication number: US3400893A
Application number: US463572A
Authority: US
Inventors: Labino Dominick
Original assignee: Johns Manville
Current assignee: Johns Manville Corp; Johns Manville
Priority date: 1965-06-14
Filing date: 1965-06-14
Publication date: 1968-09-10
Anticipated expiration: 1985-09-10

Description

Sept. 10, 1968 D. LABINO 3,400,893

APPARATUS FOR FORMING GLASS FIBER PRODUCTS Filed June 14, 1965 I N VENTOR. Dawn/6K 145mm Arm/away United States Patent r 3,400,893 APPARATUS FOR FORMING GLASS FIBER PRODUTS Dominick Labino, Grand Rapids, Ohio, assignor to Johns-Manville Corporation, New York, N.Y., a

corporation of New York Filed June 14, 1965, Ser. No. 463,572 6 Claims. (Cl. 239-592) ABSTRACT OF THE DISCLOSURE A glass fiber flame attenuating burner comprising a combustion chamber of increasing transverse crosssectional configuration in an axial direction from the fuel and air inlet orifice to approximately the mid-section of the chamber and of decreasing transverse cross-sectional configuration in an axial direction from the mid-section to its discharge orifice.

.This invention relates to method and apparatus for the production of a high temperature and high velocity attenuating blast. More specifically, the invention is directed to a new type of attenuating blast which is used in the manufacture of glass fibers by the attenuation of primary filaments of glass into fibers by subjecting such filaments to a relatively high temperature and high velocity attenuating blast. Although specifically directed to the manufacture of glass fibers, it is understood that the invention may also be utilized in the attenuating of other similar types of materials such as rock, slag, and the like.

In the manufacture of glass fiber, with the apparatus conventionally used in the industry, much trouble has been encountered in maintaining a satisfactorily large percentage of the fibers within a desired range of diameters. Thus for many reasons, a glass fiber product will contain numerous fibers which have diameters substantially greater than the average diameter of the desired type of fiber. These large diameter fibers even when present only in small amounts result in a fibrous product which in unfriendly to the touch and which is commonly described as being itchy. This unfrienclliness to the touch is more commonly present in the glass fiber products of greatest commercial significance. This problem relative to the unfriendliness of these fibers has been generally recognized in the art, and many unsuccessful attempts have been made to solve it so as to produce glass fiber products that have increased friendliness to the touch.

It is an object of the invention to provide method and apparatus for attenuating filaments of glass into glass fibers havingincreased friendliness to the touch.

It is another object of the instant invention to provide method and apparatus for controlling the burning of combustibles and comburents so as to provide an attenuating blast having a minimum degree of eddy currents and turbulence therein.

The foregoing objects are accomplished in accordance with the instant invention by a glass fiber product manufactured utilizing apparatus comprising a novel burner for producing a new type of attenuating blast into which glass filaments are fed for attenuation into fibers. The burner includes a combustion chamber of increasing transverse cross-sectional configuration in an axial direction from the inlet orifice to approximately the mid section of the chamber and of decreasing transverse cross-sectional configuration in an axial direction from the mid section to the discharge orifice thereof. The combustion chamber, in the preferred embodiment of the in vention, is substantially symmetrical about the transverse plane passing through the axial midpoint of the comice bustion chamber. It is believed that the combustion chamber of the instant invention results in an attenuating blast which is more laminar in flow than the attenuating blasts produced by conventional burners utilized in the manufacture of glass fibers. Also, this burner operates at a noise level substantially below that of conventional type burners.

This invention will be more fully understood and further objects and advantages thereof will become apparent when reference is made to the following detailed description of a preferred embodiment of the invention and the accompanying drawings in which:

FIG. 1 is a schematic elevational view of apparatus of the invention;

FIG. 2 is a plan view of the burner of the instant invention; and

FIG. 3 is a section taken of the plane passing through the line 3--3 of FIG. 2.

As shown in FIG. 1, the apparatus adapted to the production of glass fibers utilizing the burner structure of the present invention includes a glass melting crucible 20 supported within an insulated chamber 22 and heated by suitable means such as gaseous products of combustion introduced through one or more conduits 24. The base 26 of the crucible 20 is provided with a plurality of apertures 28 through which molten glass may flow in the form of primary filaments 30. The filaments 30 are gathered and directed between a pair of power driven rolls 32 and subsequently in contact with guide block 34. The guide block 34 is provided on its rear face 36 with a plurality of vertically disposed and parallel aligned guide grooves (not shown) into which the primary filaments 30 are threaded and thereby retained in proper alignment for presentation to the hot gaseous blast 38 emitted from burner 40.

The blast 38 from the burner 40 softens and reduces the primary filaments 30 into fine fibers 80. The force of the blast 38 projects the fibers through a hood 82 for deposition on an endless foraminous collection conveyor 84. A suction box 86 disposed behind the collection conveyor 84 imposes suction on the fiber-s 80 and as sists in their deposition into mat form 88. A binder may be sprayed upon the fibers as they approach the collection area.

From the collection conveyor 84, the mat 88 is transferred onto a second conveyor 92 which carries the mat through an oven 94 wherein the binder 90 is cured to produce a bonded mat 96 which may be rolled into a package 98. This subsequent treatment of the glass fibers 80 relative to the application and curing of the binder is varied according to the product to be formed or the desired use of the glass fibers.

The burner 40, illustrated specifically in FIGS. 2 and 3, comprises a combustion chamber 42 defined by walls of refractory brick 44 which is encased by a metal housing 46. In the illustration in FIGS. 2 and 3, the refractory brick 44 is shown as one complete brick, however, it is to be understood that the refractory brick defining the combustion chamber 40 may comprise a plurality of bricks of various types of refractory material joined together by any suitable means to provide the desired shape of the combustion chamber. As is illustrated in FIGS. 2 and 3, the combustion chamber 42 is of substantially constant width from the inlet orifice 48 to the discharge orifice 50 as defined by the

walls

52 and 54 of the refractory brick 44. The first section of the combustion chamber 42 is defined by the sloping walls 56 and 58 of the refractory brick 44 so as to provide a section having an increasing transverse cross-sectional configuration in an axial direction from the inlet orifice 48 of the burner to approximately the mid point 60 of the combustion chamber 42. The second section of the combustion chamber is defined by the

sloping walls

62 and 64 of the refractory brick 44 so .as to provide a section having a decreasing transverse cross-sectional confiiguration in an axial direction from the mid point 60 of the combustion chamber 42 to the discharge orifice 50. As noted particularly in FIG. 3, the first and second sections of the combustion chamber 42 are substantially symmetrical from the transverse plane passing through the mid point 60 of the combustion chamber. In the preferred embodiment of the invention, the only difference between the first and second sections of the combustion chamber is due to the differences in height of the inlet orifice 48 as compared to the discharge orifice 50. If desired, ignition means such as a spark plug (not shown) adjacent the inlet orifice 48 may be provided to facilitate ignition of the combustible mixture.

Although the mid point 60, in the preferred embodiment of the invention as described above and illustrated in FIG. 3, has been defined as the juncture of the sloping walls 56 and 58 with the

sloping walls

62 and 64, the mid point 60 may be extended to comprise a generally rectangular section of maximum transverse cross-sectional configuration having a relatively short axial extent.

In the preferred embodiment of the invention, the transverse cross-sectional configuration of the combustion chamber 42, taken in any plane transverse to the longitudinal axis of the tunnel, is generally rectangular in order to facilitate the issuance of a generally fiat and wide attenuating blast through the generally rectangular shaped discharge orifice 50. The configuration of the inlet orifice 48 is also preferably rectangular to facilitate the uniform distribution of the mixture of combustibles and comburents across the width of the combustion chamber 42.

In operation of the burner 40, a mixture of gases comprising combustibles and comburents is fed through the conduit 68 into a plenum 70 and then through the inlet orifice 48 into the combustion chamber 42. This mixture of gases is ignited initially by a spark from any suitable source and thereafter burning is continued by the heat of combustion and the heat of the refractory brick 44. As the mixture of gases burns in the combustion chamber 42, it also moves in an axial direction from the inlet orifice 48 to the mid point 60. The increasing transverse cross-sectional configuration in this first section of the combustion chamber 42 allows for the proper burning and expansion of the mixtures of gases. As the burning mixture passes the mid point 60 and continues to move toward the discharge orifice 50, the ever decreasing transverse cross-sectional configuration as defined by the

sloping walls

62 and 64 acts on the products of combustion to produce a hot gaseous blast of relatively high temperature and high velocity issuing from the discharge orifice 50. The shape of the combustion chamber 42 as defined by the sloping

walls

62 and 64 acts on the gaseous products of combustion so that the gaseous blast 38 issuing through the discharge orifice 50 has a minimum of eddy currents or turbulence therein so as to be in a higher state of uniform or laminar flow than the gaseous blast which normally issues from conventional burners of this nature. This characteristic of the attenuating blast 38 functions to hold to a minimum any entanglement of or contact between the fibers being formed from the filaments 30. One of the reasons for the formation of relatively large diameter fibers from the filaments 30 is that one fiber may contact another fiber before either has been fully attenuated and cooled so that the contacting fibers are fused together into a fiber having a relatively large diameter and even in some instances to result in what is known .as an unfiberized particle. The production of many fibers of relatively large diameters in a glass fiber product results in giving that fibrous product an unfriendly hand or feel. This tendency of early contact prevails in a highly turbulent attenuating blast. Also, a highly turbulent gaseous blast 38 has a tendency to entangle the fibers to such an extent that the fibers are broken resulting in a shortening of the length thereof.

Burners, embodying the inventive concepts of the instant application, have been operated successfully, without blowoff, in attenuating glass filaments into fibers. In one embodiment of the invention, the combustion chamber was defined by refractory brick 44 so as to have a substantially constant width of 4.25 inches. The cooperating sections of refractory brick 44 were positioned so as to form an inlet orifice having a height of about 0.0625 inch and the taper of the walls 56 and 58 was such to provide a mid point 60 having a height of about 2.00 inches. The

walls

62 and 64 were provided with a taper from the mid point 60 so as to provide a discharge orifice having a height of about 0.25 inch. The axial length of the combustion chamber 42 from the inlet orifice 48 to the discharge orifice 50 was 11 inches with the mid point being located in an axial direction approximately 5.50 inches from the inlet orifice 48. This burner produced an attenuating blast 38 having a velocity pressure measured in inches of water column of 18 inches at a temperature of 2890 F. Thus, in this embodiment of the invention, the ratio of overall length of the combustion chamber 42 to maximum height is 5.5 to 1 and the taper of the walls defining the combustion chamber is about 20 degrees. In accordance with the instant invention, a combustion chamber having a constant width of about 4.25 inches may have a ratio of overall length of the combustion chamber to maximum height between about 4.0 to l and 6.5 to l with the taper of the walls defining the combustion chamber being between about 18 to 25 degrees.

The burner 40 described in the previous paragraph was used to produce glass fibers from conventional glass filaments 30 drawn from the melting crucible 20 wherein the filaments had an average diameter of .018 inch. In one instance, the attenuating blast 38 was used to convert the filaments into glass fibers which were collected to form a glass fiber product which, because of the uniformity of fiber diameter and other characteristics not fully identified, had the hand or feel of friendliness of a glass fiber product which would be normally classified as a higher quality product having substantially lower average fiber diameters.

Another feature of the instant invention is the generally low noise level of the burner. Conventional burners for producing an attenuating blast capable of attenuating filaments into fibers are generally characterized by a whining sound which produces a relatively high noise level. In most instances, burners of this type operate at a noise level between about and decibels. However, the specific burner described above and made in accordance with the inventive concepts of the instant application operated at a noise level of 94 decibels.

While the invention has been described in rather full detail, it will be understood that these details need not be strictly adhered to and that various changes and modifications may suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What I claim is:

1. Burner apparatus comprising:

(a) a combustion chamber defined by walls of refractory brick extending in a longitudinal direction from an inlet orifice at one axial extremity thereof to a discharge orifice at the other axial extremity thereof,

(b) said combustion chamber having substantially a constant width from said one axial extremity to said other axial extremity thereof,

(c) said combustion chamber having a first section extending from said inlet orifice to approximately the mid section thereof,

(d) said first section being defined by said walls so as to have an increasing transverse cross-sectional configuration from said inlet orifice to said mid section thereof,

(e) said combustion chamber having a 'secondsection (g). said first and second sections of the combustion chamber being substantially symmetrical from the transverse plane passing through the mid section of said combustion chamber and the said increasing and decreasing of the transverse cross-sectional configuration of the first and second sections being of constant angles in relation to the longitudinal axial direction of the combustion chamber.

2. Burner apparatus comprising: v

(d) said first section being defined by sloping walls so as to have an increasing transverse cross-sectional configuration from said inlet orifice to said mid section thereof,

(e) said combustion chamber having a second section extending from said mid section thereof to said discharge orifice,

(f) said second section being defined by sloping walls so as to have a decreasing transverse cross-sectional configuration from said mid section thereof to said discharge orifice,

(g) said first and second sections of the combustion chamber being substantially symmetrical from the transverse place passing through the mid section of said combustion chamber and the said increasing and decreasing of the sloping walls of the transverse cross-sectional configuration of the first and second sections being of constant angles in relation to the longitudinal axial direction of the combustion chamber,

(h) means for introducing a mixture of combustible and comburents into said combustion chamber for burning therein to produce an attenuating fluid, and

(i) said walls of said combustion chamber acting on said attenuating fluid to reduce the eddy currents and turbulence therein to a minimum.

3. Burner apparatus comprising:

(a) combustion chamber defined by walls of refractory brick extending in a longitudinal direction from an inlet orifice at one axial extremity thereof to a discharge orifice at the other axial extremity thereof,

(d) said first section being defined by said walls so as to have a uniformly increasing transverse cross-sectional configuration at a constant angle from said inlet orifice to said mid section thereof,

(c) said combustion chamber having a second section extending from said mid section thereof to said discharge orifice,

(if) said second section being defined by said walls so as to have a uniformly decreasing transverse crosssectional configuration at a constant angle from said mid section thereof to said discharge orifice, and

(g) said combustion chamber being substantially symmetrical relative to a transverse plane passing through the axial mid point thereof.

4. Burner apparatus comprising:

(b) said combustion chamberhaving substantially a constant width from said one axial extremity to said other axial extremity thereof,

- (d) said first section being defined by said walls so as to have an increasing transverse cross-sectional configuration from said inlet orifice to said mid section thereof,

(f) said second section being defined by said walls so as to have a decreasing transverse cross-sectional configuration from said mid section thereof to said discharge orifice,

(g) said first and second sections of the combustion chamber being substantially symmetrical from the transverse plane passing through the mid section of said combustion chamber and the said increasing and decreasing of the transverse cross-sectional configuration of the first and second sections being of constant angles in relation to the longitudinal axial direction of the combustion chamber, and

(h) said mid section being defined by the juncture of said first and second sections.

5. Burner apparatus comprising:

(b) said combustion chamber having substantially a constant width from said one axial extremity of said other axial extermity thereof,

(h) said combustion chamber having a generally rectangular configuration in any transverse cross-sectional plane.

6. Burner apparatus comprising:

(a) a combustion chamber defined by walls of refractory brick extending in a longitudinal direction from an inlet orifice at one axial extremity thereof 7 to a dicharge orifice at the other axial extremity thereof,

(d) said first section being defined by sloping plane walls so as to have a uniformly increasing transverse cross-sectional configuration from said inlet orifice to said mid section thereof,

(if) said second section being defined by sloping plane Walls so as to have a uniformly decreasing transverse cross-sectional configuration from said mid section thereof to said discharge orifice,

(g) said combustion chamber having a generally rectangular configuration in any transverse cross-sectional plane,

(h) said first and second sections of the combustion chamber being substantially symmetrical from the transverse plane passing through the mid section of said combustion chamber and the said increasing and decreasing of the sloping walls of the transverse cross-sectional configuration of the first and second sections being of constant angles in relation to the longitudinal axial direction of the combustion chamber,

(i) means for introducing a mixture of combustibles and comburents into said combustion chamber for burning therein to produce an attenuating fluid, and

(j) said walls of said combustion chamber acting on said attenuating fluid to reduce the eddy currents and turbulence therein to a minimum.

References Cited UNITED STATES PATENTS 2,643,415 6/1953 Stalego 65-7 2,687,551 8/1954 Stalego 65-7 2,982,991 5/1961 Karlovitz 65-16 X FOREIGN PATENTS 1,225,709 7/1960 France.

DONALL H. SYLVESTER, Primary Examiner.

25 R. L. LINDSAY, JR., Assistant Examiner.