US2529962A - Method and apparatus for producing mineral wool - Google Patents

Description

E. R. POWELL Nov. 14, 1950 METHOD AND APPARATUS FOR PRODUCING MINERAL WOOL Filed May 17, 1947 INVENTOR ion 4&0 e paw :44.

TORNEY Patented Nov. 14, 1950 METHOD AND APPARATUS FOR PRODUCING MINERAL WOOL Edward R. Powell, North Plainfield, N. J., assignor to J ohns-Manville Corporation, New York, N. Y., a corporation of New York Application May 17, 1947, Serial No. 748,863

I 12 Claims.

The instant invention relates to a method and apparatus employed in the production of mineral wool, and more particularly to an improved rotor construction for use in the spinning process of mineral wool production. As used herein the term mineral wool is intended to include fibrous material formed from slag, rock, glass, mixtures thereof and other heat liquifiable materials which may be drawn out into fibrous form.

For many years mineral wool has been made by flowing a stream of the molten material in front of a high pressure steam jet which shreds the stream into a multiplicity of fibers. More recently it has been proposed to employ one or more rotors revolving at high speeds, the molten material being deposited on the rotors to form incandescent rings. The fibrous material is produced from a multitude of minute portions of the material which leave the rotor surfaces and draw out into long fine fibers under the influence of the centrifugal forces set up. This method has been found to produce finer and longer fibers and to permit a higher recovery than is the case with the conventional blowing process.

The principal object of the invention is the provision of an improved rotor construction for use in the spinning process which will contribute to the production of a high yield of fine uniform fibers.

Although rotors having tires of heat resistant steels or alloys have been proposed, it has been found that the high temperature of the molten material of the incandescent rings causes rapid erosion or wear, the surface metal apparently becoming amalgamated to some extent with the molten material. Applicant determined that a reduction in temperature of the rotors from the temperature of the molten material, which may reach 2700 F., to say 600 to 900 F. greatly increases the effective life of the rotors. Accordingly, a primary object of the invention is the provision of a rotor construction adapted for the application of a cooling medium adjacent the rotor surfaces.

A further object of the invention is the provision of a cooling system which is subject to control to enable the rotor surfaces to be maintained at the temperatures necessary for efiicient operation. Overcooling, such as may be obtained by conventional waterjacketing with consequent reduction of the rotor temperature to substantiall that of hot Water, has been found to unduly chill the molten material and result in coarse fibers and lowered production.

A still further object of the invention is the provision of a rotor construction including means for delivering water or other vaporizable liquid in controlled quantities into the interior of a hollow rotor adjacent the rear surface of the rotor rim whereby the rotor rim is cooled by the vaporization of the liquid.

A still further object is the provision of a rotor and of its method of operation which will insure the retention of a relatively permanent ring of the raw material from which the fibers are drawn to provide a supply of the molten material for fiberization and to protect the rotor surface.

My invention will be more fully understood and further objects and advantages will become apparent when reference is made to the following detailed description of a preferred embodiment of the invention and to the accompanying drawings in which Fig. 1 is a sectional view, with parts in elevation, taken on the line of Fig. 2; and

Fig. 2 is a front elevational view of the rotor.

Referring to the drawings, there is shown a rotor indicated generally at I Q and adapted for use in mineral. wool fiberizing equipment of the spinning type, for example, that shown in my copending application Serial No. 742,064, filed April 17, 1947, now abandoned. The rotor includes a tire l2 made of a steel or alloy relatively resistant to high temperatures, such as chromium-nickel-iron alloys and chrome-molybdenum-iron alloys and the like. The tire has an outer annular surface M adapted to receive the molten mineral material, such as slag, rock, glass or the like, to be fiberized, and for that purpose the annular surface may be provided with grooves 55 or other surface indentations of suitable shape to retain the material in the form of annular rings.

Tire I2 is provided with annular grooves l8 and 20 in its side faces, the grooves receiving flanges 22 and 24 of end plates 26 and 28 respectively. The end plates and tire together define a hollow interior section 30.

The rotor, comprising the end plates and the tire, is supported on a shaft 32 adapted to be mounted in suitable bearings for rotation at high speed. The bearing structure and driving means form no part of the instant invention and hence have not been shown. The shaftincludes a hub 34 including an enlarged boss 36', a cylindrical section 31 and a threaded end 38 of reduced diameter. End plate 26 has a central aperture shaped to fit against boss 36, and end plate 28 is provided with a recessed central portion defining a flange 42 fitting around the threaded end 38 of the hub and engaging section 31. The tire l2 and end plates 26 and 28 are held in assembled relationship on the shaft by a threaded collar 44 fitting recess 40 and screwed onto the end 38 of the shaft to overlie flange 42, and also by studs 46 extending through aligned openings in the several parts and threaded into boss 36.

Shaft 32 is provided with a center bore 50 extending the length of the shaft with its forward end closed by plug 52 threaded into a socket 54. End plates 26 and 28 are formed with thickened annular sections 55 having inner edges adjoining the cylindrical section 31 of hub 34 and fitting around studs 46. The annular sections are tapered at their outer edges to leave annular openings and 62 adjacent the inner corners of tire I2. Ducts or bores 64 extend radially outwardly from the bore 50 of shaft 32, the ducts passing through the hub and the thickened sections of the end plates to lead to the annular openings 60 and 62. A suitable number of the ducts are provided. In the embodiment shown each end plate has four with adjacent ducts lying at right angles to one another.

One or more vents 66, four being shown, are provided in one of the end plates, suitably plate 26 defining the rear side of the rotor, the vents extending axially through the plate between tire -l2 and hub 34. Drainage openings 68 are also provided, the drainage openings extending from the inner surface of the tire to the outer corners of notch- cs 22 and 24.

The rotor construction described above may be used, for example, for the rotors lfi'and l8 disclosed in my said co-pending application. The rotor is supported on a substantially horizontal axis for rotation at high speed and the molten material, at a temperature which may be as high as 2700 F., is continuously discharged onto the rotor surface to form a relatively permanent bonded ring 10, the fibers being drawn out from surface portions of the ring as indicated at T2. In order to conduct away the excess heat imparted to the rotor by the molten material and maintain the rotor tire at the desired temperaturefor maximum efficiency, say GOO-900 F., a vaporizable liquid, preferably water; is intro- .duced in controlled quantities to the bore 58 of shaft 32 from any suitable source, not shown. The water passes through the bore and enters ducts 54 whichconductit directly to the inner surface of tire 12. Movement of the water through the ducts is accelerated by the centrifugal forces set up by the rotation of the rotor. Relatively small quantities are employed whereby the Water, when it reaches the tire, is immediately vaporized, the heat of vaporization being drawn from the tire. The water vapor or steam may readily escape through openings 66. In the event excess water is introduced into the rotor, for example, if the water is left on during a period in which no molten material is supplied to the rotor or the rate of supply of the molten material is slowed, the water may escape through ducts 68. Grooves l8 and 2B are sufficiently over-size with respect to flanges 22 and 24 to leave sufficient room for the excess water to trickle out.

A rotor construction as described above permits relatively precise control of the rotor tem perature inasmuch as the temperature reduction will be directly determined by the quantity of water introduced for vaporization. Hence both overheating of the rotor which contributes to its rapid deterioration and overcooling which results in coarse fibers and loss of production, are avoided.

The controlled cooling in cooperation with the grooves [6 in the rotor surface also serves the important function of insuring the retention of a relatively continuous layer or ring of material over the major part of the active surface of the rotor. Cooling to the extent stated, say to 600 to 900 R, where a conventional slag wool melt is employed, solidifies or partially solidifies the material directly on the rotor surface to form a base to which the liquid incandescent material adheres and provides a supply of the material from which the fibers are drawn. The relatively permanent ring or layer also protects the rotor surface from undue wear or erosion by the molten material continuously discharged against it.

Only relatively small quantities of water are needed for the controlled cooling. For example, fiberizationat the high rate of 3600#/hr. of the molten material has been found to require the use of only about 15 gal. of water per hour. The rotor is of simple construction and may be readily assembled and dis-assembled to permit the replacing of tires I2 when excessive wear has occurred.

Having thus described my invention in rather complete detail it will be understood that these details need not be strictly adhered to but that various changes and modifications may be made, all coming within the scope of the invention as defined by the s'ubjoined claims.

What I claim is:

1. In a rotor construction, a tire having annular grooves in the side walls thereof, end

plates having flanges extending into the annular grooves and defining with the tire a hollowinterior section, a bored shaft supporting said rotor for rotation, and ducts leading from the bore to the hollow interior section adjacent the tire, whereby a cooling liquid may be introduced through said bore and conducted directly to said tire. I

2. In a rotor construction as defined in claim 1, said ducts lying in part within an end plate and in part within the shaft.

3., In a rotor construction as defined in claim 1 vents in an endplate and'located between the tire and shaft for the escape of steam created by the vaporization of the cooling liquid.

4. In a rotor construction, a tire having annular grooves in the side walls thereof, end plates having flanges extending into the annular grooves and defining with the tire a hollow interior section, a bored shaft includinga hub supporting the rotor for rotation and ducts in part within said end plates and leading from said bore to the hollow interior section adjacent the tire.

5. In a rotor construction as defined in claim 4, vents in the end plates and located between the tire and shaft for the escape of steam created by the vaporization of the cooling liquid, and drainage ducts leading outwardly from the inner surface of the tire.

6 A rotor comprising an annular tire, said rotor having a hollow interior section definedin part by said tire, a bored shaft supporting said rotor for rotation, and ducts in said rotor and leading from the bore of the shaft and opening into the hollow interior sectionat points ad jacent the tire and spaced from the shaftwhere by a cooling liquid introduced through said bore is conducted directly to said tire. r 1

7. A rotor comprising'an annular tire and end plates defining a, hollow interior section with said tire, a bored shaft supporting said rotor for rotation, and passageways leading from the bore of said shaft in a radial direction through an end plate to said hollow interior section at points adjacent said tire whereby cooling liquid introduced through said bore is conducted directly to said tire.

8. In a rotor as defined in claim 6, drainage ducts extending outwardly from the interior surface of the tire.

9. Ina rotor construction, a tire having annular grooves in the side walls thereof, end plates having flanges extending into the annular grooves and defining with the tire a hollow interior section, a bored shaft supporting said rotor for ro-,

tation, ducts leading from the bore to the hollow interior section adjacent the tire whereby a cooling liquid may be introduced through said bore and conducted directly to said tire, vents in one of said end plates and located between the tire and shaft for the escape of steam created by vaporization of the cooling liquid, and drainage ducts extending outwardly from the interior surface of the tire for the escape of unvaporized liquid,

10. The method comprising, discharging molten material onto a peripheral surface of a rotor having a hollow interior defined in part by a peripheral wall, and introducing a vaporizable liquid in controlled quantities into said hollow interior at predetermined points adjacent said peripheral wall whereby the liquid is conducted directly to the wall and is immediatel vaporized by the heat imparted to the wall by the molten material without the accumulation of substantial quantities of liquid within the hollow interior and the temperature of the wall is lowered to an extent determined by the quantity of liquid material introduced.

11. The method of forming mineral wool on equipment including a rotor comprising a tire having outer and inner peripheral surfaces and a hollow interior defined in part by said inner peripheral surface, said method comprising, discharging molten mineral material onto the outer peripheral surface of the tire and introducing a vaporizable liquid in controlled quantities into said hollow interior at predetermined points adjacent said innerperipheral surface whereby the liquid is immediately vaporized by the heat imparted to the tire by the molten material without the accumulation of substantial quantities of liquid within the hollow interior and the temperature of the tire is lowered to an extent determined by the quantity of liquid material introduced.

12. A rotor comprising an annular tire and end plates, said rotor having a hollow interior section defined in part by said tire, a bored shaft supporting said rotor for rotation, passageways in said rotor leading from the bore of the shaft to points in the hollow interior section adjacent the tire whereby a cooling liquid introduced through said bore is conducted directly to said tire, and vents in an end plate and located between the tire and shaft for the escape of steam produced by vaporization of the cooling liquid.

EDWARD R. POWELL.

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

UNITED STATES PATENTS Number Name Date 687,524 Fellner Nov. 26, 1901 1,051,844 Passow Jan. 28, 1913 2,295,639 Drill Sept. 15, 1942

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