US2888060A - Arrangement and method for the production of mats or similar flat formations of mineral wool - Google Patents

Description

May 26, 1959 ARRANGEMENT AN D METHOD FOR THE PRODUCTION OF MATS Filed May 20, 1957 s 0. K. KJELL-BERGEl Q OR SIMILAR FLAT FORMATIONS OF MINERAL WOOL 2 Sheets-Sheet l Y 1a J ATTORNEYS 2 ,888,060 2 SheetSheet 2 y 1959 s. 0-. K. KJELL-BERGER ARRANGEMENT AND METHOD FOR THE PRODUCTION OF MAT 0R SIMILAR FLAT FORMATIONS 0F MINERAL WOOL Flled May 20, 1957 United States Patent ARRANGEMENT AND METHOD FOR THE PRO- DUCTION OF MATS 0R SIMILAR FLAT FORMA- TIONS .OF MINERAL WOOL Sven Olof Kjell Kjell-Berger, Skovde, Sweden, assignor to Rockwool Akfiebolaget, Skovde, Sweden, :1 corporation of Sweden Application May 20, 1957, Serial No. 660,278

Claims priority, application Sweden May 23, 1956 9 Claims. (01. 154-27 Mats of spun mineral wool are employed, particularly within the building industry, for a variety of insulation purposes. The mats are commonly bound together with sewing, the body of the mat comprising mineral wool spun from glass fiber, from molten stone, or similar material. In the production of the mats, fine fibrous particles are spun from a machine which uses the mineral in molten form to spin a mass of particles which are known in bulk as mineral wool. The fibrous particles are extruded upon a slowly moving conveyor on which they are compressed into a mat, enclosed between two strips of impregnated paper, the strips being sewn together to form the bound mat.

The mass of mineral particles is also commonly subjected to treatment with an oil of low volatility, with a plastic resin, or some other binding material which is intended to impregnate and bind the particles into a more coherent mass.

Difliculty has arisen in the manufacture of these mats, however, in assuring that the bound mats Will have a constant or substantially constant volume weight. The mineral material to be used in spinning the fibrous particles is normally molten into a thin liquid consistency. To accomplish this, a cupola furnace is often used. The ovens are charged in layers of the mineral and of the fuel. As the fuel burns, the mineral charge becomes molten, Stratification takes place, and the charge is released in the form of a thin jet Within the spinning machine. The quantity of mineral charge supplied to the spinning machine for unit of time is dependent upon conditions within the furnace, such as the amount of charge in a molten state as compared with that remaining in a somewhat semi-molten state. Other conditions are also significant, such as unevenness in the original charge which causes irregularity in the supply of molten material to the spinning machine.

Because of these difficulties, and because of the variance in the amounts of fibrous material extruded from the spinning machine, a somewhat heterogeneous final product is obtained. Although the mineral Wool mass is subjected to compression and the thickness of the wool mat can be standardized accordingly, the insulative power, the volume weight, and the resiliency of the mat will nevertheless vary along the length of the mat on the conveyor.

Variations in these characteristics of the mat are observed to occur in relation to the feed of molten material to the spinning machine. While these variations can be somewhat counteracted by adjusting correspondingly the speed of the conveyor collecting the mineral wool, manual control of the speed is scarcely possible as one cannot observe by eye any particular phenomena which make it possible to judge whether the speed of the conveyor needs to be increased or decreased. Nor can the speed of the conveyor be controlled on the basis of the weight of mineral wool deposited. For at the time when an increase in the speed of the conveyor would be necessary, already an excess of mineral wool would have been deposited. And where aldecrease in theamount of wooldeposited "Ice occurred, it would not be-possible at a later time to account for the dilference by some means; involving reasonable costs and time.

According to the instant invention, the aforementioned disadvantages are overcome by regulating the speed of the conveyor in relation to the power consumed by the spinning machine. The invention is predicated upon the observation that the power consumed by the spinning machine varies in accordance with the quantity of mineral wool extruded by the machine. Variances in power consumption are of such magnitude as to permit their measurement and the regulation of the speed of the conveyor accordingly.

Thus, by the method described herein the volume weight of the mineral wool mat per unit length of the conveyor is maintained at a substantially constant value.

In a preferred embodiment, the control apparatus for regulating the speed of the conveyor in relation to the power consumed by the spinning machine is mounted along the feeder circuits leading to the electrical power means for the spinning machine. The invention will become more evident from the following description, to be read in connection with the attached drawings, wherein this preferred embodiment is set forth.

In the drawings, Figure 1 shows diagrammatically the overall arrangement of the invention. Figure 2 shows, diagrammatically also, an arrangement ofthe speed control means as indicated at 31 in Figure 1.

It is to be understood that the instant invention is not limited to use with any one kind of spinning machine. Many different kinds of spinning machines, tested in accordance with the present invention, have demonstrated the property of their power consumption varying closely linearly with the amount of mineral wool extruded from the spinning machine per unit of time. As described herein, the invention is applied in connection with a spinning machine having rotating wheels, from the surface of which the mineral is expelled in the form of wool particles. But the invention is nevertheless applicable 'with all kinds of spinning machines which are commonly employed in practice'for the production of mineral wool.

The invention also contemplates simultaneous control of the feed of the many kinds of impregnating materials, or the various other operations which etfect the uniformity of the wool mat.

In the drawings it can be seen that 10 indicates a cupola furnace in which the mineral is melted down to be spun into the wool. The mineral is charged in layers 11, 12, and 13, alternate to layers of fuel 14, 15, and 16. Forced air is fed through an inlet 17 for supporting combustion. A melt 18 is collected in the bottom of the furnace and released through outlet 19 in the form of a freely falling jet 20.

The jet 20 falls into the spinning machine generally indicated at 21. According to the particular embodiment described herein, the spinning machine 21 comprises a number of wheels which rotate with different speeds. The wheels are so arranged that the jet 20 hits a first wheel moving at a low speed, from which the melt is thrown over to a second wheel moving at a higher speed, and finally to a third wheel moving at a still higher speed. Only the first and third wheels are visible in Figure 1 at 22 and 23, respectively.

The spinning machine 21 may be driven by a single motor or by a plurality of motors. In Figure l the machine is driven by two separate motors 24 and 25, motor 24 driving the spinning wheel 22 and the second spinning wheel not shown in the figure, over a power transmission 26, the second motor 25 driving the third spinning wheel 23 over a power transmission 27 r 'The motors themselves are actuated through 3-phase'current over feeding lines 28 and 29 which in turn are fed from a main 30through assaoeo the control apparatus 31, which is dealt with ingreater detail in Figure 2.

The control apparatus 31 functions so as to measure the amount of power fed over the conduits 28 and 29 to the motors 24 and from the main 3%. In relation to this power value, control apparatus 31 regulates the voltage value or some other suitable value on an output control conduit 32, over which a motor 33 is fed with current from a direct current network 34.

From the spinning wheels, or at least from the last of the spinning wheels 23, a cascade of spun mineral wool 35 is deposited on a conveyor 36 moving in the direction of the arrow 37 under the influence of the motor 33. A mat 38 of mineral Wool is built up on the conveyor 36, and the resultant mat is compressed by means of a loaded roller 39. Just beyond, the compressed mat is transferred to a second conveyor 40 driven through a power transmission not shown in the drawing synchronously with the conveyor 36. Belt driving may be arranged between the shaft for the last support roller 41 of the first conveyor 36 and the first support roller 42 of the second conveyor The formed mineral wool mat is transferred to the second conveyor ll with constant thickness and without any tendency to displace in a horizontal direction such that it would be further compressed or torn apart. Conveyor 40 carries the wool mat to a point where the later operations for forming the bound mat are accomplished. These operations do not form any part of the instant invention.

Control apparatus 31 functions so as to regulate the speed of the motor 33 in relation to the consumption of power of the motors 24 and 25 driving the spinning machine 21. Motor 33 drives the conveyor 36 and indirectly the conveyor 46. Regulation of the speed of the conveyor occurs in such a way that the rate at which the mat 38 builds up on the conveyor is adapted to the quantity of mineral wool deposited from the spinning machine such that after compression to a uniform thickness the mat 38 will also have a substantially constant volume weight.

Binder material is also introduced in the spinning machine to the mineral wool mass. Moreover, the amounts of binder material fed to the mass are similarly fed in relation to the power consumption of the spinning machine. Normally the binder material is fed as a shower distributed through the hollow shafts of the spinning t /heels 22 and 23. In the arrangement according to Figure 1, the material is fed to these shafts at their left end by means of flexible piping 43 and 44, the pipes themselves being fed by means of a pump 45 driven by the motor 46. The speed of the motor 46 is also regulated oil of the output control. conduit 32.

A preferred embodiment of the control apparatus 31 itself shall now be described with reference to Figure 2.

Schematically shown at 47 is a 3-phase motor, which may be the only motor or one of several motors driving the spinning wheels. The motor 47 is fed with current over the 3-phnse conductor 48 which represents schematically the 3-phase conductors 28 and 29 shown in Figure l. The primary winding of a current transformer $9 is connected into one of the phase conductors, and the secondary winding is connected to the worker winding 50 of an ampere metrical control instrument, the pointer 52 of which is turnable about the shaft 51. The pointer 52 supports a screen 53 of an appropriate arc length. This screen is positioned between two discs 54 and 55 which are turnable about a shaft 51" co-axial with the shaft 51 but mechanically free from shaft 51'. Each of the discs 54 and 55 contains an arc-shaped slot or opening 56 and 57 respectively, the arc radius of the slots being substantially the same as that of the screen 53. On the far side of the disc 55 are two sources of light having optics 60 and 61 directing concentrated beams of light perpendicular to the disc 54 and 55 and to the screen 53.- Normally the screen 53 lies in the path of these beams of light such that the beams are prevented from striking a pair of photoelectric cells 58 and 59. When, through the action of the ampere metrical instrument, the screen 53 is displaced to one side or the other, either the beam of light from the source '69 will hit the photoelectric cell 53 or the beam from source 61 will hit the photoelectric cell 59.

The photoelectric cells 58 and 59 are each connected to one of a pair of DC. current amplifier electronic tubes 62 and 63 which straddle a common bias battery 64 connected into the grid-cathode circuit, or some other suitable source of bias voltage of such a magnitude that when the photoelectric cells are unstimulated, the electronic tubes will be non-conductive. In the anode circuit of the tubes 62 and 63 are relays 65 and 66, respectively, connected to be actuated when the electronic tubes become conductive. A reversible motor 67, for the sake of simplicity drawn as a direct current motor with two magnetizing windings 68 and 69 coupled in opposite directions, is connected to the mains over one of the contacts 70 and 71 on the relays 65 and 66 such that the motor will rotate in one direction when the tube 62 is conductive and the relay 65 is actuated. The motor 67 will rotate in the opposite direction when the tube 63 is conductive and the relay 66 is actuated. Through a gear 7%" with a large gear ratio the motor 67 is connected to the transmitter '71" in a Selsyn system, the three condoctor system of which is indicated at 72. This three conductor system feeds two different motors, first, a Selsyn motor 73 which through a gear 74 turns the discs 54 and 55, and second, a second Selsyn motor 75 which through a worm gear 76 sets a speed control resistor 77 and 78 for the motor 33. The motor 33 is that shown in Figure l for driving the conveyor 3640. The shaft of the worm gear 7 6 is combined with a control arm 77 for the speed control resistor 78 which is connected in the circuit of the motor 33.

The foregoing arrangement functions in the following manner: When the amount of mineral wool expelled from the spinning wheels increases for one reason or another, the motors indicated schematically in Figure 2 by 47 are loaded more heavily. This load increase results in an increased voltage in the secondary winding of the transformer 49 whereby the pointer 52 of the ampere metrical instrument is moved in a clockwise direction. Consequently, the screen 53 is displaced in such a way that the light beam from the light source 60 strikes the photoelectric cell 58 and the tube 62 becomes conductive. T he relay 65 is thus actuated, its contact 7% is closed, and the servomotor 67 is activated in such a direction to change the angular position of the transmitter of the Selsyn system and its two receivers, bringing the arrangement into balance once more. The receiver 75 is turned in such a direction that the resistance 78 is decreased whereby the speed of the motor 33 is increased correspondingly. The receiver 73 simultaneously is turned in such a direction that the discs 54 and 55, together with the light sources 60 and 61 and the photoelectric cells 58 59, are reset in the direction in which the arm of the pointer of the ampere metrical instrument had been turned the moment before. This movement continues until both of the light beams are again screened by screen 53, the tube 62 thus becoming non-conductive once more, the relay 65 being released, the contact 7 0 opening again, the motor 67 stopping, and the Selsyn system having again resumed a state of balance. In result, however, the motor 33 will rotate with a somewhat higher speed corresponding to the higher consumption of power by the spinning Wheel motors and the increased quantity of spun mineral wool deposited on the conveyor, such that the volume weight of the mineral wool mat remains substantially constant at all times along the length of the conveyor.

On the other hand, if the consumption of power by the spinning wheel motors decreases, simultaneous with a corresponding decrease in the amount of spun mineral wool ejected by the spinning wheels, the operation occurs in a somewhat opposite fashion. The beam of light from the light source 61 strikes the photoelectric cell 59, the tube 63 becomes conductive, and the relay 66 is actuated. The motor 67 rotates in a direction opposite to that occurring with an increase in consumption, and the whole Selsyn system is activated in the opposite direction. The resistor 78 is reset in such a direction that the motor 33 undergoes a decrease in speed, and the discs 54 and 55 are turned in the opposite direction until the screen 53 again obstructs the beam of light from the light source 61 such that it does not reach the photo electric cell 59. Thereafter, the whole arrangement assumes a state of balance adapted to the new speed of feeding the spun mineral wool to the conveyor.

Although the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be efiected without departing from the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

What is claimed is:

l. A method of producing mats of mineral wool having substantially constant volume-weight comprising the steps of feeding a molten mineral mass to a spinning machine, allowing the spun wool particles to be deposited on a conveyor, uniformly compressing the mass of particles thus deposited, and controlling the speed of said conveyor in relation to the variations in power consumed by the spinning machine such that the volume-weight of wool per unit length of said conveyor remains substantially constant.

2. A method according to claim 1 further including the step of controlling the amount of binding material fed to said machine in relation to the power consumed by said machine.

3. A method according to claim 1 wherein said spin ning machine is powered by electrical means and control of the speed of said conveyor is effected by means provided in the feeder circuits to said electrical means.

4. An arrangement for producing mats of mineral wool having substantially constant volume-weight comprising means for producing a molten mineral mass, a

machine for spinning mineral wool particles from said mass, means for powering said machine, a conveyor for catching and collecting the spun wool particles emanating from said machine, means for driving said conveyor, means for uniformly compressing the mass of particles collected on said conveyor, and means for regulating the speed of said conveyor in relation to the power consumed by said machine such that the volume-Weight of wool per unit length of said conveyor remains substantially constant.

5. An arrangement according to claim 4 further comprising means for feeding binding material to said machine, said regulating means also regulating the amounts of said material fed to said machine in relation to the power consumed by said machine.

6. An arrangement according to claim 4 wherein said powering means is electrically actuated and said regulating means is placed in the feeder circuits to said powering means.

7. An arrangement according to claim 6 wherein said driving means is electrically actuated, said regulating means comprising means for measuring fluctuations in current through said feeder circuits, and means for controlling the voltage across said driving means corresponding to said fluctuations.

8. An arrangement according to claim 7 wherein said control means comprises at least one light source, at least one photoelectric cell, means for preventing light from said source from reaching said cell, said preventing means being displaceable by said measuring means, and means for adjusting the resistance in-the feeder circuits for said driving means when said preventing means is displaced.

9. An arrangement according to claim 8 wherein said last named means also includes means for realigning said preventing means with said source and said cell so as to prevent light from reaching said cell again.

References Cited in the file of this patent UNITED STATES PATENTS 2,305,516 Coss et a1 Dec. 15, 1942 2,450,914 Powell Oct. 12, 1948 2,561,843 Coleman July 24, 1951

Images