US3122792A - Machines for spraying asbestos or the like - Google Patents

Description

March 3, 1964 Filed May 25, 1959 B. MOODY 3,122,792

MACHINES FOR SPRAYING ASBESTOS OR THE LIKE 4 Sheets-Sheet l March 3, 1964 B. MOODY 3,122,792

MACHINES FOR SPRAYING ASBESTOS OR THE LIKE Filed May 25, 1959 4 Sheets-Sheet 2 Inventor B P/Q- h M 00 B Attorney;

March 3, 1964 B. MOODY MACHINES FOR SPRAYING ASBESTOS OR THE LIKE Filed May 25, 1959 4 Sheets-Sheet 5 f 2 H w 4 Inventor 871' Meet,

ttorneys March 3, 1964 B. MOODY 3,122,792

MACHINES FOR SPRAYING ASBESTOS OR THE LIKE Filed May 25, 1959 4 Sheets-Sheet 4 I n ventor 57th Mood,

6 E q Attorneys United States Patent C) 3,122,792 MACHINES FOR SPRAYING ASBESTO GR THE LIKE Bryan Moody, Clayton-le-Woods, Charley, England, assignor to I. W. Roberts Limited Filed May 25, 1959, Ser. No. 815,486 Claims priority, appiication Great Britain May 30, 1958 9 Claims. (Cl. 19-93) This invention relates to that kind of machine by which asbestos or other mineral fibres are formed into a suspension and sprayed onto a surface to form a coating on it as insulation against heat and sound.

In the operation of machines of this kind the fibres are commonly supplied to a hopper, and they should be extracted from this and conveyed forwards at a uniform rate. In practice there is considerable difiiculty in doing this.

An important object in this invention is to provide an improved apparatus for extracting asbestos fibres from a hopper and conveying them onwards.

The essence of the present invention is the provision at the base of the hopper of two or more toothed rollers arranged so that when they are stationary they essentially support the mass of fibres in the hopper, but when they rotate they draw the fibres downwards. In practice asbestos and similar fibres fed to a machine from sacks are in the form of clots or lumps, and even though the toothed rollers may exert a combing action on the fibres as they move downwards it is found in practice that clots tend to pass through them. These rollers may advantageously be a central toothed roller and two lateral toothed rollers, the latter moving at faster peripheral speeds to exert a combing action on the fibres.

Means are provided for breaking up clots of fibre that have passed between the rollers. These means may in clude the rollers or may be wholly separate from them.

In one convenient form of construction a supporting surface is provided below the rollers, preferably of inverted shallow V shape, to serve two purposes. In practice there are not only clots of fibre but also smaller flocks which, when the toothed rollers are stationary, may pass between them, and on passing tend to clog the apparatus and make it difiicult to start it into motion. The supporting surface below the rollers retains a large number of such flocks. Secondly the supporting surface may with advantage be arranged only a short distance below the rollers so that clots of fibre cannot easily pass between the supporting surface and the rollers without being struck by the teeth of the rollers and broken up.

The means for breaking up clots may also comprise a rotary drum having vanes which strike any clots of fibre and tend to break them. Both these means of breaking up clots may be provided in a single machine.

Another device for breaking up clots of fibre that have passed between the toothed rollers comprises a rotary disc mounted about a vertical axis within a casing, the fibre (including any clots) falling on this disc and being flung radially into contact with the casing and broken by impact both onto the disc and in turn onto the casing.

In all cases the rate of delivery of the fibre by the toothed rollers should be less than the rate at which the conveying means can carry fibre to a spraying fan or than the fan can receive fibre without choking. There fore in operation there is always some void space below the supporting surface and between it and the part by which the fibre is next engaged.

Machines according to the invention will now be shown by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a part sectional and part elevational view around the cylindrical surface.

3,122,792 Patented Mar. 3, 1964 ice of one machine, various driving connections being omitted for the sake of clarity;

FIGURE 2 is a section on the line IIII in FIGURE 1 with a drum shown in elevation;

FIGURE 3 is a partly diagrammatic side elevation of the same machine;

FIGURE 4 is a plan of this machine;

FIGURE 5 is a side elevation of another machine; and

FIGURE 6 is a section through a smaller machine.

The machine shown in FIGURES 14 comprises a hopper 1 of rectangular section, tapering from wide at the top to narrow at the bottom. The sides 2 and 3 taper continuously but the sides 4 and 5 are vertical at the top. Three rollers 6, 7 and 8 having teeth in the form of spikes 9 are mounted rotatably and horizontally in bearings in opposite walls near the bottom of the hopper. Each roller is hollow and the spikes 9 mostly project radially from it, but project at an angle near the end so as to ensure that some spikes (9a) work close to the walls of the hopper. Sprockets 10, 1t), 10" on shafts projecting outside the hopper from corresponding ends of each roller are interconnected by a chain drive 11. The sprockets on rollers 6, 8 and 7 have 12, 24 and 36 teeth respectively so that the speeds of rotation of these rollers are always in the ratio 3:2:1.

If the hopper is filled with asbestos fibre of the consistency in which it is found in a bale compressed for transporting and the fibre is forced down into the hopper so that it comes into contact with the spikes on the roller, revolution of the rollers will then cause the spikes to tear into the fibre, exerting a combing action on it, and pull it downwards. The tearing eifect of the rollers on the fibre pulled down greatly depends on the ratio of the speeds of rotation of adjacent rollers. Inevitably some clots of as bestos pass between the rollers. Moreover when the rollers are stationary small flocks of asbestos may pass between them. Below the rollers there is a stationary sup porting surface 12 of inverted V shape in cross section, the V being shallow as shown in FIGURE 1. This surface 12 is formed by sheet metal spanning the sides of the hopper and it prevents clots drawn down between the rollers 6 and 7 from falling directly onto the drum 14. Similar clots that pass between the rollers 7 and 8 are trapped between the right-hand side of the surface and the spikes on the roller 8. In addition when the apparatus is temporarily not in use, e.g. because the operator has stopped it for a short time, small flocks of asbestos that may fall between the rollers descend onto the surface 12 and are largely retained there. In the absence of the surface they would tend to move further downwards and thereafter, by clogging the parts beneath the surface 12, make it difficult to start the machine again.

Below the surface 12 there is a cylindrical drum 14 which carries radial vanes 16 running parallel to the axis In addition each end of the drum carries vanes extending radially from the axis to the cylindrical circumference as shown at 15. The drum 14 rotates so that the vanes 16 catch the falling fibre and fling it towards a metering cylinder 17 mounted to rotate about a parallel axis and in the same direction. Conveying spikes 18 inclined to the axial planes of the cylinder project from the curved surface thereof, and pick up the fibre gathered by the vanes 16 when this fibre is brought round and onto the cylinder 17. The fibre picked up by the cylinder is carried round by it to the point where it is stripped from it by a carded stripping brush 19 rotating in the opposite direction to the cylinder at a higher surface speed. The stripped fibre is now sucked as a suspension through a tube 20 by a fan 21 and so to a spraying nozzle not shown. A steel comb 22, fixed adjustably to the walls of the casing 23 in which the metering cylinder and associated parts are housed, combs the fibre as it is \K N p a revolved on the metering cylinder and just before it is removed by the stripping brush, and by evening it makes its removal easier.

All rotating parts are driven by a variable speed electric motor 24. Some of the driving connections are omitted in FIGURE 1, and these connections are best shown in FIGURE 3. A sprocket 25 on the motor shaft drives a sprocket on the shaft of the cylinder 17 by a chain 26, and this drive is transmitted to sprockets on the shafts of the brush 19 and drum 14 by a chain 27 and a crossed belt 28 respectively. The preferred speeds of rotation of therotating parts 19, 17 and 14 are 466, 12 and 235 rpm. respectively, the size of the pulleys being chosen to give these speeds and internal reversing gearing (not shown) Within the drum 17 causing it to rotate in the same direction as the cylinder 14 even though the belt 28 connecting them is crossed. Another chain drive 29 connects another pulley on the shaft of the cylinder 17 with a gearbox 30 and this drive is transmitted to the shaft of the roller 8 by means of a chain 31. By means of the gearbox 30 the'speeds of rotation of the rollers 6, 7 and 8 may be altered without alteration of the speeds of rotation of the parts 19, 17 and 14 or of the motor 24 and vice versa. 7 In the construction shown in FIGURE there are a hopper 1, rollers 6, 7 and 8, a supporting surface 12, and a vaned drum 14 which are essentially the same in construction and operate in the same Way as in the machine shown in FIGURES 14. The vaned drum fiings the fibre it collects to an endless conveyor belt 52, supported at either end by rollers 33, 33'. Spikes 34 projects from the face of the belt and fibre caught by the belt off the drum 14 is raised to the top of the belt where a stripping brush 35, Working like the brush 19 already described, removes it from the conveyor, the fibre then falling into the suction inlet of a fan 36 which delivers the fibre to a nozzle. An

evener brush 37 revolves close to the top of the belt and ensures that the belt is carrying no thicker a layer of fibre than is wanted by the time it reaches the stripping brush. The evener brush acts to skim the surplus fibre from the belt and fling it backwards.

In the construction shown in FIGURE 6, three spiked rollers 38 work at the bottom of a small hopper 39. The relative speeds of rotation of these rollers, and the way in which they are driven are similar to the corresponding features of the rollers 6, 7 and 8 already described. Fibre pulled from the hopper by the rollers falls onto a disc 40 rotated about a vertical axis, and having radial ribs 41 projecting from its upper surface. The disc flings the fibre centrifugally outwards as a suspension in air, and this suspension is sucked downwards through the annular gap 42 surrounding the disc by a fan impeller 43 carried by a vertical shaft 45 which also carries the disc 40. The shaft 45 is driven by a motor 46, and fibre received by the impeller 43 is delivered by it through an outlet 44 to a spray nozzle.

. I claim:

1. In a machine for forming asbestos or other mineral fibre into a suspension in air and spraying it onto a surface, the combination of a hopper for the fibre, means bounding a space below the hopper, at least first and second toothed rollers laterally offset from one another and mounted within the lower part of the hopper above said space to turn about parallel substantially horizontal axes, said rollers being adapted to engage the fibre and draw it downwardly, a third toothed roller mounted within the lower part of the hopper to turn about a substantially horizontal axes parallel to, higher than and vertically between the axes of the said first and second rollers, means to drive said first, second and third rollers, said driving means driving said third roller at a lower peripheral speed than said first and second rollers for loosening asbestos to pass to the first and second rollers, the paths of the tips of the teeth of the first, second and third rollers being spaced apart in directions perpendicular to the axes of the rollers, the three rollers together serving when they are stationary to support the mass of fibres in the hopper, and means for breaking up clots of fibre that have passed the rollers.

2. Machine according to claim 1 in which the means for breaking up the clots include a supporting surface arranged only a short distance below the rollers so that clots of fibre cannot easily pass between the supporting surface and the rollers without being struck by the teeth of the rollers and broken up.

3. Machine according to claim 1 in which the means for breakin up clots include a rotary drum having vanes adapted to strike and break clots of fibre.

4. Machine according to claim 1 in which the means for breaking up the clots comprise a casing and a rotary disc mounted about a vertical axis within the casing, to receive the fibre (including any clots) falling from the rollers and fling it radially into contact with the casing.

5. Machine according'to claim 4 which includes a fan exerting suction on the space between the disc and the casing and mounted below and coaxial with the disc.

6. Machine according to claim 4 in which the disc has radial ribs on its upper surface.

7. Machine according to claim 1 including a fan and conveyor means for transferring fibre from beneath said means for breaking up clots of fibre towards said fan.

8. Machine according to claim 7 in which the conveyor means is a rotary drum with a spiked surface.

7 9. Machine according to claim 7 in which the conveyor means is a spiked belt.

References Cited in the file of this patent UNITED STATES PATENTS 469,560 Groom Feb. 23, 1892 690,614 Rodgers Jan. 7, 1902' 830,646 Davis Sept. 11, 1906 959,746 Humason May 31, 1910 1,769,669 Wuest July 1, 1930 2,646,381 Duvall July 21, 1953 2,764,013 Harrell Sept. 25, 1956 2,883,709 Deems et al. Apr. 28, 1959

Claims (1)

1. IN A MACHINE FOR FORMING ASBESTOS OR OTHER MINERAL FIBRE INTO A SUSPENSION IN AIR AND SPRAYING IT ONTO A SURFACE, THE COMBINATION OF A HOPPER FOR THE FIBRE, MEANS BOUNCING A SPACE BELOW THE HOPPER, AT LEAST FIRST AND SECOND TOOTHED ROLLERS LATERALLY OFFSET FROM ONE ANOTHER AND MOUNTED WITHIN THE LOWER PART OF THE HOPPER ABOVE SAID SPACE TO TURN ABOUT PARALLEL SUBSTANTIALLY HORIZONTAL AXES, SAID ROLLERS BEING ADAPTED TO ENGAGE THE FIBRE AND DRAW IT DOWNWARDLY, A THIRD TOOTHED ROLLER MOUNTED WITHIN THE LOWER PART OF THE HOPPER TO TURN ABOUT A SUBSTANTIALLY HORIZONTAL AXES PARALLEL TO, HIGHER THAN AND VERTICALLY BETWEEN THE AXES OF THE SAID FIRST AND SECOND ROLLERS, MEANS TO DRIVE SAID FIRST, SECOND AND THIRD ROLLERS, SAID DRIVING MEANS DRIVING SAID THIRD ROLLER AT A LOWER PERIPHERAL SPEED THAN SAID FIRST AND SECOND ROLLERS FOR LOOSENING ASBESTOS TO PASS TO THE FIRST AND SECOND ROLLERS, THE PATHS OF THE TIPS OF THE TEETH OF THE FIRST, SECOND AND THIRD ROLLERS BEING SPACED APART IN DIRECTION PERPENDICULAR TO THE AXES OF THE ROLLERS, THE THREE ROLLERS TOGETHER SERVING WHEN THEY ARE STATIONARY TO SUPPORT THE MASS OF FIBERS IN THE HOPPER, AND MEANS FOR BREAKING UP CLOTS OF FIBRE THAT HAVE PASSED THE ROLLERS.

Images