US3194443A

US3194443A - Rock duster

Info

Publication number: US3194443A
Application number: US292017A
Authority: US
Inventors: Glenn D Gurney
Original assignee: American Mine Door Co
Current assignee: American Mine Door Co
Priority date: 1963-07-01
Filing date: 1963-07-01
Publication date: 1965-07-13
Anticipated expiration: 1982-07-13

Description

July 13, 1965 G. D. GURNEY 3,194,443

ROCK DUSTER Filed July 1, 1963 5 Sheets-Sheet 1 AfrroRNEYs INVENTOR Glemumey BY VWM G. D. GURNEY ROCK DUSTER 5 Sheets-Sheet 2 Filed July 1, 1963 mw Illnw ma /w F H ON. H I .l: p m mw S. O

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INVENTOR. @Zalm/. Gfzznzey {fz/warg, www? am ATTORNEYS G. D. GURNEY July I3, 1965 nocx DUsTER I Filed July l, 1965 5 Sheets-Sheet 5 INVENTOR. lemD. Gunzey ATTORNEYS G. D. GURNEY July 13, 1965 ROCK DUSTER 5 Sheets-Sheet 4 Filed July l, 1963 INVENTOR. ZeIm/D. G11/Hwy 97mg, Wl' ML;

ATTORNEYS July 13, 1965 Filed `Ju1y"1, 196s G. D. GURNEY ROCK DUSTER 5 Sheets-Sheet 5 INVENTOR.

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ATTORNEYS United States Patent O 3,194,443 ROCK DUSTER Glenn D. Gurney, Canton, Ohio, assigner to The American Mine Door Company, Canton, Ohio, a corporation of Ohio Filed July 1, 1963, Ser. No. 292,017 2t) Claims. (Cl. Z22- 193) The invention relates to apparatus for spreading rock dust in coal mine tunnels and the like, for covering and mixing with the coal dust on the walls, ceilings, and iloors, and more particularly to an apparatus of this general type having novel conveying means as well las novel spreading means for the rock dust.

It is common practice to spray the interiors of coal mine tunnels and similar places with rock dust in order to prevent explosion of the coal dust 4which accumulates on the oor, walls and ceilings thereof.

The apparatus generally used for this purpose comprises a vehicle which may be 'arranged to be propelled upon the railroad rails in the mines or otherwise, such vehicle having a hopper containing a supply of rock dust. Screw means is usually provided for feeding the -rock dust Ifrom t-he hopper to a feed tube or pipe through which an air blast is passed -for spraying the rock dust from a nozzle connected to the feed tube.

In Ithe past, di'iculty has been experienced by the rock dust having a tendency to pack and arch over the feed screw and pack in the ffeed tube, so that yfeeding of the rock dust to the nozzle is interrupted, requiring stopping of the operation to break up the packed or caked rock dust.

Furthermore, this feeding of the rock dust from the hopper to the feed tube, by a feed screw, and then spraying it through the nozzle was a slow operation.

The object of Ithe present invention is to provide a rock dusting apparatus which overcomes the above diticulties and disadvantages, and which will quickly and easily convey the rock dust to the spreading means and rapidly spread it upon the walls, ceilings and floors of mine tunnels and similar pl-aces.

Another object -of the invention is to provide rock dusting apparatus having simple, effective and inexpensive means for rapidly and uniformly conveying the rock dust without any danger of packing or caking.

A further object of the invention is to provide apparatus of the character referred to having conveying means of the general type disclosed in Ihlefeldt Patent No. 1,971,853, dated August 28, 1934, in which a conveying trough has a porous bottom wall through which air or gas under pressure is forced to maintain the pulverulent material being conveyed in a suspended state approximating a fluid condition.

A still further object of the invention is to provide rock dusting apparatus of this character comprising a hopper or bin for containing rock dust, the bottom wall of the hopper or bin being in the form of a porous flexible member inclined slightly downward toward the discharge end.

Another object of the invent-ion is to provide such a rock dusting apparatus in which fan air-tight chamber is located lbeneath t-he hopper or bin, the porous flexible member forming the top W-all of the air-tight chamber, means being provided for admitting a gaseous medium under pressure to said Iair-tight chamber at spaced points v throughout the length thereof.

A still further object of the invention is to provide a rock duster of -this general type in -which the rock dust is discharged from two spaced outlets in the end wall of the hopper or b-in, directly into two preferably oppositely rotating fans which spread the rock dust evenly over the Vehicle.

surfaces of the ceiling, side walls and tioor of a tunnel or similar place in a coal mine.

The .above and other objects, apparent from the drawings and following description, may be atta-ined, the above `described diiiiculties overcome `and the advantages and results obtained, by the apparatus, construction, arrangements and combinaitons, sub-combinations and parts which comprise the present invention, a preferred embodiment of which, illustrative of the best mode in which applicant has contemplated applying the principle, being set forth in detail in the following description and illustrated in the accompanying drawings.

In general terms the invention may be briefly described as comprising an elongated hopper or bin having an open top7 substantially vertical rside walls and end walls, and a ilexible porous bottom wall, slightly inclined from one end wall to the other.

An air-tight chamber is located directly below and coextensive with the inclined bottom wall, which 4forms the top wall of said air-tight chamber. Means, such as lan air pump, is provided for furnishing air or other gaseous medium, and discharge pipes from thepump communicate at spaced inter-vals with said `air chamber so as to maintain a uniform pressure throughout the air chamber.

A V-shape divider is preferably located in the discharge end of the hopper or bin, dividing the same into two diverging legs, there being a discharge slot in the adjacent end wall at the terminal end of each leg.

A motor is mounted beyond the other end of the hopper or bin and operatively connected, as by sprocket wheels and chain, w-ith the air pump for driving the same. A main drive shaft is located centrally below the a-ir cham- -ber and also connected by sprocket wheels and chain with the motor.

A spaced pair of transversely disposed plates are located yforwardly from the discharge end of the hopper or b-in and extend entirely across the discharge end thereof. Between these transverse plates are located fans, one near each end of the plates.

Each fan is 4centered relative to one of the discharge outlet slots in the adjacent end wall of the hopper or bin. An opening is formed in the first of the two plates, concentric with each fan, and a U-shape trough extends between each discharge outlet slot and the corresponding opening.

One lof the fans is connected directly to the main drive shaft, as by sprocket wheel and chain drive, and the other =fan is connected to the drive shaft through a reversing gear, so that the fans rotate in opposite directions.

Having thus briefly described the invention, reference is now made to the accompanying drawings illustrating a perferred embodiment of the invention, in which;

FIGS. la and 1b are a plan view of the new rock duster apparatus, with parts broken away for the purpose of illustration;

FIGS. 2a and 2b are a side elevation with parts broken away;

FIG. 3 is an elevation of one end of the apparatus, showing the motor, and the starter box;

FIG. 4 is an elevation of the opposite end of the apparatus, showing the fans;

FIG. 5 is a section on the line 5 5, FIG. 1b; and

FIG. 6 is a section on the line 6 6, FIG. 5.

The apparatus is designed to be moved through mine tunnels and the like, and is adapted to be mounted on a vehicle which may be arranged to be conveyed upon a railroad track by means of a locomotive or otherwise. The vehicle is not illustrated as it in itself forms no part of the invention. l

The apparatus comprises a rectangular frame, indicated generally at 1, adapted to be mounted upon the This frame includes longitudinally disposed angle members 2, joined at their rear ends by a transversely disposed angle member 3, and at their forward ends by the transversely disposed plate 4, to which the vertical angle members are also attached.

' Vertical angle members 6'are connected to therear transverse member 3 and at their upper ends are connected by a transverse angle member 7. A pair of vertical angle members 8 are mounted upon the longitudinal members 2, at points spaced forwardly from the rear end of the apparatus, and a transversely disposed plate 9 is connected at opposite ends to the upper portions there- Atransversely disposed angle member 1@ is connected to the upper edge of the transverse plate 9. Longitudinally disposed angle members 11 are located between opposite ends of the transversely disposed angle members 7 and 10, and a centrally located angle member 11a is located between the central portions of the transverse angle members 7 and 10, forming a support for a cover plate 12 for the rear portion of the frame.

A spaced pair of transversely disposed angle members 13 are mounted at opposite ends upon the longitudinally disposed frame members 2, at a point spaced forwardly from the rear transverse angle member 3, and provide a support for the motor 14, the flanged feet 15 of which are mounted upon angle members 13 and connected thereto by bolts 16.

Spaced, transversely disposed angle members 17 and ISvare located forwardly of the angle members 13 and connected at their opposite ends to the longitudinal angle members 2. A short angle Vmember 19 is mounted upon one end portion of the member 17.

An air'pump 2t) is provided with anged feet-21 connected to the

angle members

13 and 19 by bolts 22. Sprocket wheels 23, upon the shaft 24 of the motor 14, are connected by chains 25 with sprocket wheels 2.6 upon the main drive shaft 27 which is longitudinally centrally located through the frame.

The shaft 27 is journalled in a bearing 28 mounted upon the transversely disposed angle member 17 and in bearings 29 and 30 mounted upon the transversely disposed

angle members

31 and 32. Bolts 33 and 34 attach g the bearings 29 and 30 to the

angle members

31 and 32.

A sprocket wheel 35, upon the shaft 27, is connected by chain 36 with sprocket wheel 37 upontheshaft 3S 'of the air pump 20. A hopper, indicated generally at 39, is formed within the frame 1 between the

transverse walls

4 and 9 which form the front and rear end walls for the hopper, the longitudinal Vside walls of which are shown at 40.

The bottom wall of the hopper is slightly inclined orwardly and downwardly from the rear wall 9 toward the front wall 4. This bottom wall 41 is porous and preferably flexible and, as best shown in FIGS. 5 and 6, is preferably formed of several layers of canvas supported by a heavy wire mesh 42 which is supported upon the transverse angle members 43. The longitudinal edges of the canvas 41 are turned up against the side walls 4t) and are clamped thereagainst by the longitudinal bars 41a and bolts 41b. Y n

A gas chamber 44 is located below the hopper and, coextensive therewith. The front and

rear end plates

4 and 9 respectively form the front and end Walls of the gas chamber and the lower portions 45 of the side walls 41B form the side walls thereof.

The lower terminal edge of the side walls 40 are turned inwardly as shown at 46 in FlG.- 5 and the bottom wall 47 of the gas chamber is attached thereto and supported on the transverse angle members 46.

Air or other suitable gaseous medium under pressure is discharged from the airpump 20 through then pipe 50 which is-connected to the two longitudinally disposed pipes 51 located beneath the gas chamber 44 near opposite sides thereof and kconnected at spaced intervals to the gasY chamber as indicated at 52.

A V-shape or triangular divider 53 may be Vlocated in the forward end vof the hopper dividing this end of the hopper into two diverging legs indicated at 54and 55 in FIG. lb, A discharge outlet slot 56 is formedin the end wall 4 at the end of

eachrleg

54 or 55 and at the oor level thereof as shown in FIGS. 5 and 6.

Longitudinally diagonally disposed angle members 57 are located upon the bottom wall 47, directly below the bottom edges of the V-shape dividerV 53, as best shown in FIGS. 1b and 5. The inner edges of the canvas 41, and wire mesh 42, are located upon the corresponding angle members 57 and clamped thereupon by bolts SS located through the horizontal flanges V59 at the lower edges of the V-shape divider 53 and through the angle members 57. Y

Y The endl of the canvas-41 is located through the corresponding discharge outlet slot 56 and extends downalong the front face of the end plate 4 as indicated at 60. Each end portion 60 of the canvas is clamped against the front face of the end plate 4 by the corresponding bearing block 61 and bolts 62 (FIGS. 1b and 6).

Two vertically aligned transversely disposed plates 63- 63 are located in front of the end plate 4 and spaced therefrom, and the transversely disposed plate 64 is spaced forwardly from the plates 63-63.

A pair of similar fans 65-65' are provided. The fari 65 is located between the

plates

63 and 64 and the fan 65 is located between the plates '63 and 64. The shaft 66 of fan 65 and the shaft S1 of fan 65Yeach has one end journalled in a bearing 67, which may be a roller bearing or ball bearing, located in a bearing block 61.V The other end of the shaft 66 of the fan 65 is journalled in a bearing 68, mounted upon an angle member 69 carried by the plate 64.

A sprocket wheel 7@ is fixed upon the forward end of the shaft 66 of the fan 65and connected by chain 71 with sprocket wheel 72 upon the forward end ofV the main shaft 27, which is journalled in a-bearing'73, mounted upon a bracket 74, carried by the angle member 69.

The reversing gear box 75 isVm-ounted upon a bracket 76 carried by the transverse plate 64. A sprocket wheel 77, upon the shaft 7S of the reversing gear, is connected by chain 79 with sprocket wheel 8i) upon the main drive shaft 27. The shaft S1, of the fan 65, is connected within the reversing gear box 75,.the other end thereofbeing journalled in a bearing 67 located within the corresponding bearing box 61.

Each plate 63 and 63Yhas an opening S2 therein concentric with the corresponding fan shaft 66 and 81. A substantially channel-shape trough 83 is located in front of each outlet slot 56, being mounted upon the correspending bearing block 61, and extends to a point adjacent the corresponding opening 82 in the

transverse piate

63 or 63 as the case may be.

T he

plates

63, 63 and 64 are supported from the front end plate 4 by means of the double partition indicated generally at 84. T his partition is located between the

fans

65 and 65 and comprises the two parallel vertical portions 235 connected at their upper ends as at 36, each vertical portion 85 merging intopa downwardly curved portion 7 which terminates below the outer side of the adjacent fan with forward and rearward cutouts 3S and S9 and reduced terminal portion 9d therebetween. i

The double partition above described is welded to the end plate 4 at its inner edge as indicated at 91 and welded to the outer `transverse platey 64 at its outer edge as at 92.* The inner transverse plates 63 and 63' are shaped to fit theV contours of the two

vertical portions

8,5 and curved portions S7 of the double partition.

An angle member 93- is attached to the upper edges of the inner transverse plates 63 Vand 63 and to angle members 94 connected Yto the forward side of the end plate 4. Y

ln the Voperation of the apparatus, the hopper is filled with rockY dust and the vehicle carrying the apparatus is conveyed to the location within a mine tunnel to be dusted. The motor 14 is then started :operating the shaft 27 through the sprocket gearing 23-25-26.

The air pump is thus operated through the sprocket and chain gearing 35-36-37 and the

fans

65 and 65 are rotated in opposite directions by the sprocket and chain gearing 70-71-72, sprocket and chain gearing 78-79-3@ and reversing gear 7S.

Air under pressure is discharged from the pump 20, through the pipe Sil and tubes 51 and into the air chamber 44, at spaced points thr-oughout'its length, through the connections 52. The air under pressure is forced upwardly from the air chamber, through the porous bottom wall 41, maintaining the rock dust in such condition that it assumes the characteristics of a fluid emulsion.

The air under pressure passing up through the porous bottom wall 41 passes upward through the rock dust, separating each particle of rock dust from the other particles thereof.

The rock dust in this condition will be conveyed forwardly upon the porous bottom wall, being diverted by the triangular separator 53 into the two

legs

54 and 55 of the hopper and discharged through the discharge outlet slots 56 and through the channel-shaped troughs 83 and the openings 82, into the rapidly rotating fans 65 and 65', which throw the rock dust upwardly and outwardly in opposite directions, uniformly coating the ceiling and side walls of the mine tunnel with rock dust, a sucient number of the rock dust descending to the oor of the mine so as to adequately cover, or mix with, the coal dust thereon.

From the above it will be evident that a simple, etlicient and easily operated apparatus is provided for rapidly and uniformly dusting the side walls, ceiling and floor of a mine tunnel or the like, without the diflicult-ies and disadvantages of present rock dusting apparatus.

In the foregoing description certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be -implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of eX- ample, and the scope of the present linvention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantages new and useful results obtained thereby; the new and useful construction, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlets in one end wall, a gas chamber below and coextensive with the bottom wall, means for introducing a gaseous medium under pressure into said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the `fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, and means for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

2. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being yspaced discharge outlets in one end wall, a gas chamber below and coextensivel with the bottom wall, means for introducing a gaseous medium under pressure into said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, and means for rotating the fans in opposite directions with the upper sides of the fans rotating toward each other, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse Walls.

3. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlets in one end wall, a gas chamber below and coextensive with the ybottom wall, means for introducing a gaseous medium under pressure into said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, said innermost transverse wall being spaced from said one end wall, a substantially channelshape trough between each disch-arge outlet and the correspending concentric opening, and means for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets into said channel-shape troughs and drawn from said troughs into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

4. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlets in one end wall, a gas chamber below and coextensive with the bottom wall, means for introducing a gaseous medium under pressure into said gas Chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a vertical partition between said transverse walls on the inner side of each fan, each of said partitions merging into an outwardly curved portion terminating beneath the corresponding fan, and means for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

5. A rock duster comprising a hopper having side walls, end walls, and a forwardly and downwardly inclined porous bottom wall, there being spaced discharge outlets in the forward end wall, a gas chamber below and coextensive with the bottom wall, means for introducing a gaseous medium under pressure into said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends yof said transverse walls, there being openings concentric with the fans in the innermost transverse wall, and means for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transveise walls.

6. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlets in one end wall, a gas chamber below and coextensive with the bottom wall, means for introducing a gaseous medium under pressure into said gas chamber, aftransversely disposed rotary fan located in disease 7 front of each discharge outlet, spaced transverse, walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a vertical partition between said transverseV walls on the inner side of each fan, each of said partitions merging into an outwardly curved portion terminating beneath the corresponding fan in a reduced terminal portion, and means for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

7. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlet in one end wall, `a gaschamber below and coe'xtensive with the bottom wall, means for introducing a gaseous medium under pressure into said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse Wall, a vertical partition between said transverse walls on the inner side of each fan, each of said partitions merging into an outwardly curved portion terminating beneath the corresponding fan, means joining the upper ends of said vertical partitions, and means for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

8. A rock duster comprising a hopper having side walls, end walls, and a flexible porous bottom wall, there being spaced discharge outlets in one end wall, a gas chamber below and coextensive with the bottom wall, means for introducing Va gaseous medium under pressure into said gas chamber, a transversely Vdisposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being s Vopenings concentric with the fans in the'innermost transverse wall, and means for rotating the fans in opposite directions, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

9. A rock duster comprising a hopper having side walls, end walls, and a forwardly and downwardly inclined flexible, porous bottom wall, there being spaced discharge outlets in the forward end wall, a gas chamber below and coextensive with the bottom wall, means for introducing a gaseous medium under pressure into said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, and means for rotating the fans in opposite directions, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly therebyrfrom between said transverse walls.

10. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlets in one end wall, a gas chamber below and coextensive with the bottom wall, an air pump, tubes communicating with the discharge side of the air vpump 'and connected to said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan l,and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wa1l,fa motor, a'drive shatt operatively connected to said motor, means operatively connecting the air pump to the drive shaft, and means operatively connecting the fans torthezdrive shaft for rotating the fans, whereby rock dust willbe conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

ill. A rock duster comprising a hopper having side walls, end walls and aV por-ous bottom wall, there being spaced discharge outlets in one end wall, a Vgas chamber below and coextensive with the bottom wall, anfair pump, tubes communicating with the discharge side of the air pump and connected to said gas chamber, a transversely disposed rotary fan located in front of each dischargeoutlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a mot-or, a drive shaft operatively connected to said motor, means operatively connecting the air pumpto the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans in opposite directions, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawninto said fans and will be blown upwardly and outwardly ,thereby from between said transverse walls; v

l2. A rock duster comprising a hopper having side walls, end walls and a porous bottom wall, there being 'spaced discharge outlets in one end wall, a gas chamber below and coextensive with the bottoml wall, an air pump, tubes communicating with the discharge side of the air Vpump and connected to said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transversewalls between'which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall,'a substantially channel-shape trough between 'each discharge outlet and the corresponding concentric opening, a motor, a drive shaft operatively connectedto said motor,means operatively connecting the air pump to the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans,whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets into said channel-shape 'troughsV and drawn from said troughs into said fans'and will be blown upwardly and outwardly thereby from between said transverse walls. Y

13. A rockduster comprising a hopper having side walls, end walls and a porous bottom wall, there being spaced discharge outlets in theadjacent end wall, a gas chamber below and coextensive with the bottom wall, an air pump, tubes communicating with the discharge side of the air pump and connected to said gas chamber, a transversely disposedrotary fan located' in front of each discharge outlet, spaced transverse wallsvbetween which the fans are located, the space .between said transverse walls being unobstructed above each fan Yand'at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall,v a vertical partition between said'transverse walls on the inner side of each fan, each of said partitions merging into an outwardly curvedV portion terminating `beneath the corresponding fan, a motor, a drive shaft operatively connected to said motor, means operatively connecting the air pump` to the drive shaft, and means operatively connecting the fans to the drive'shaft for rotating the'fans, whereby rock dust willrbe' conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

14. A rock duster comprising a hopper having Vside walls, end walls, and a forwardly and downwardly inclined porous bottom wall, there being spaced discharge outlets in the adjacent end wall, a gas chamber below and coextensive with the bottom wall, an air pump, tubes communicating with the discharge side of the air pump and connected to said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a motor, a drive shaft operatively connected to said motor, means operatively connecting the air pump to the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans, whereby rock dust will be conveyed along said porous bottom lwall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

1S. A rock duster comprising a hopper having side walls, end walls, and a porous bottom wall, there being spaced discharge outlets in the adjacent end wall, a gas chamber below and coextensive with the bottom wall7 an air pump, tubes communicating with the discharge side of the air pump and connected to said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed above each fan and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a vertical partition between said transverse walls on the inner side of each fan, each of said partitions merging into an outwardly curved portion terminating beneath the corresponding fan in spaced cutouts and a reduced terminal portion, a motor, a drive shaft operatively connected to said motor, means operatively connecting the air pump to the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

16. A rock duster comprising a hopper having side Walls, end walls, yand a porous lbottom Wal-l, there being spaced discharge .outlets in the Aadjacent end wall, a gas chamber below and coextensive with the b-ottom wall, an air pump, tubes communicating with the discharge side of the .air pump and connected to said gas chamber, a transversely disposed rotary han located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse walls being unobstructed .above each han and at opposite ends of said transverse walls, there being openings concentric with the fans in spaced cutouts and the innermost transverse wall, a vertical partition between said transverse walls on the inner sid-e of 'each fan, each of said partitions merging into an outwardly curved portion terminating beneath the corresponding fan in a reduced terminal portion, a motor, a ydrive shaft operatively connected to said motor, means operatively connecting the air pump to the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans in opposite directions, whereby rock dus-t will be conveyed iai-ong said porous bottom wall and through said discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse Walls.

17. A rock duster comprising a hopper havin-g side walls, end walls and a porous bottom wall, Ithere being spaced discharge outlets in the adjacent end wall, :a gas chamber below and coextensive with the bottom wall, an air pump, tubes communicating with the discharge side of the air pump and connected to said gas chamber, a transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the -fans are located, the space between said transverse walls being unobstructed above each fan .and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a vertical partition between said transverse walls .on the inner .side of each lfan, each of said parti-tions merging into an outwardly curved portion terminating beneath the corresponding fan in spaced cutouts and la reduced terminal portion, means joining the upper `ends of said vertical portions, a motor, a drive shaft operatively connected to said motor, means operatively connecting .the Iair pump to the -drive shaft, and means Ioperatively connecting the fans to the drive shaft for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall .and through said `discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

i8. A rock duster comprising a hopper having side walls, end walls, and a flexible porous bottom wall, there being spaced discharge outlets in the adjacent end wall, a gas chamber below fand coextens-ive with the bottom wal-l, and air pump, .tubes communicating with the discharge side of the air pump `and connected to said gas chamber, la transversely disposed rotary fan located in front of each discharge outlet, spaced transverse walls between which the fans are located, the space between said transverse Walls being unobstructed :above cach fan and at Vopposite ends of said transverse walls, there being openings concentric with the fans in the innermost transverse wall, a motor, la :drive shaft operatively connected to said motor, means operatively connecting the air pump to the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said -discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

19. A rock duster comprising a hopper having side walls, lend walls, `and a forwardly and downwardly inclined, flexible, porous bottom wall, means dividing said hopper into two legs, there being .a discharge outlet in the forward end wall at the end of each leg, a gas chamber below and coextensive with the bottom wall, an air pump, tubes communicating with the discharge side of the air pump and connected to said gas chamber, a tr|ansversely disposed rotary fan located in front of each dischange outlet, spaced transverse walls between which the fans are loca-ted, the space between said transverse walls being unobstructed above each lfan and at opposite ends of .said transverse walls, there being openings concentric with the dans in the innermost transverse wall, a motor, a drive shaft operatively connected Ito Isaid motor, means opera-tively connecting the air pump .to the drive shaft, and means operatively connecting the fans to the drive shaft for rotating the fans, whereby rock dust will be conveyed along said porous bottom wall and through said 'discharge outlets and drawn into said fans and will be blown upwardly and outwardly thereby from between said transverse walls.

20. A rock duster comprising a hopper havin-g side Walls, end walls, and a forwardly and downwardly inclined, lflexible, porous 'bottom Wall, means dividing said hopper into two legs, there being a discharge outlet in the forward end wall at the end of each leg, la gas chamber below and coextensive with the bottom wall, an :air pump, tubes communicating withV the discharge side of the air pump and connected to said gas chamber, a transversely disposed rotary fan located in lfront vof each discharge outlet, spaced transverse wa'lls between wh-ich the lfans are located, the space Ibetween said transverse Walls being unobstructed above each fan `and at opposite ends of said transverse walls, there being openings concentric with the fans in the innermost .tnansverse Wall, a motor, a `drive shaft operatively connected t-o said moto-r, means operatively connecting the `air pump to the drive shaft, .and means `operatively connecting fthe fans to the drive shaft for rotating the fans in opposite directions, Whereby rock dust will be conveyed along said porous bottom Wa=11 .and through said `discharge outlets ran-d'drawn into said fans and will be bl-ownuipwardly and outwardly thereby from between said transverse walls.

References Cited by thelxamner UNITED STATES PATENTS,

V1,776,751 9/30v Dim 275- 21 2,645,500 7/53 Moss 275-s X f 2,813,640 11/57 Loomis. a02- 29x 3,039,827 6/62 `immistfme er a1. Y3oz-29 X FoREiGN PATENTS 584,809 1/47 Great Britain. 1,121,544 i/62y Germany.

LOUIS J. DnMBo, Primary Examiner.

Claims

1. A ROCK DUSTER COMPRISING A HOPPER HAVING SIDE WALLS, END WALLS AND A POROUS BOTTOM WALL, THERE BEING SPACED DISCHARGE OUTLETS IN ONE END WALL, A GAS CHAMBER BELOW AND COEXTENSIVE WITH THE BOTTOM WALL, MEANS FOR INTRODUCING A GASEOUS MEDIUM UNDER PRESSURE INTO SAID GAS CHAMBER, A TRANSVERSELY DISPOSED ROTARY FAN LOCATED IN FROM OF EACH DISCHARGE OUTLET, SPACED TRANSVERSE WALLS BETEEN WHICH THE FANS ARE LOCATED, THE SPACE BETWEEN SAID TRANSVERSE WALLS BEING UNOBSTRUCTED ABOVE EACH FAN AND AT OPPOSITE ENDS OF SAID TRANSVERSE WALLS, THERE BEING OPENINGS CONCENTRIC WITH THE FANS IN THE INNERMOST TRANSVERSE WALL, AND MEANS FOR ROTATING THE FANS, WHEREBY ROCK DUST WILL BE CONVEYED ALONG SAID POROUS BOTTOM WALL AND THROUGH SAID DISCHARGE OUTLETS AND DRAWN INTO SAID FANS AND WILL BE BLOWN UPWARDLY AND OUTWARDLY THEREBY FROM BETWEEN SAID TRANSVERSE WALLS.