US2851383A - Air jet cleaning and nozzle for use therefor - Google Patents

Description

5 Sheets-Sheet 1 Sept. 9, 1958 J. A. Elm-"PLE A AIR JET CLEANING AND NOZZLE FOR USEl THEREFOR Filed Dec. 22, 1953 Sept. l9, 1958 J. A. EINHIPLE 2,851,383

AIR JET CLEANING AND NOZZLE FOR USE THEREFOR Filed Dec. 22, 1955 5 Sheets-Sheet 2- nauoconona annabee oo ...I-loo consonance.

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avsloccactaonlocooo iocoenleonoou Olnoonouooooouooo nonuooanocanun mvENToR JOHN A. EINHlPLE avm/fw ATTORNEY 2,851,383 AIR JET CLEANING AND NOZZLE FOR USE THEREFOR Filed Dec. 22. 1953 Sept. 9, 1958 J. A. EINHIPLE 5 Sheets-Sheet 3 R O T M E V m JOHN A EINHIPLE Y QJ/AW .ATTORNEY Sept. 9, l1958 Filed Dec. 22, 1953 6 '14423, G 271'.' |42 gg. 43 21 J. A.` EINHIPLE AIR JET CLEANING 'AND NozzLE Fon us5: THEREFOR 5 Sheets-Sheet, 4

JOHN A. EINHIPLE ATTORNEY Sept. 9, 1958 4 JQrElNHIPLE 2,351,383

AIR JET CLEANING AND NozzLE FOR USE.' rHgREFoR Filed Dec. 22, 1953 l "5 Sheets-Sheet 5 k l JOHN A.EINHIPLE BY. im*

ATTORNEY AIR JET CLEANNG AND N OZZLE FOR USE THEREFOR Application December 22, 1953, Serial No. 399,703 8 Claims. (Cl. 134-23) This invention is in relation to nozzles for producing iiuid jets and is directed especially to nozzles for producing a straight jet of air. The invention is more particularly directed to the cleaning out of cavities or holes, especially a great plurality of holes, such as are present in drilled acoustical tile.

One type of ceiling construction, which is now well known, includes a surface of a plurality of tiles of lowdensity wood iiberboard, the surfaces of which are provided with a multiplicity of cavities or cylindrical holes for acoustical sound absorbing purposes. Various methods, such as drilling, cutting and punching, have been provided for producing these holes in the tiles, the most common method being drilling. However, since the holes, as normally provided, extend only a portion of the distance through the thickness of tile, and since the tile is normally constructed or a material having a low density and a high yieldability, no practical method of drilling is known, as yet, capable of removing completely, from both the side and end surfaces of the hole, all of the material desired to be so removed. Nor is any method known for satisfactorily cleaning either the dust from drilling or the incompletely severed pieces of material from the hole.

Although improvements have been made in the means for producing the holes, a substantial percentage of undesired material remains in the holes decreasing the sound absorbing quality of the tile and to some degree reducing the quality from an appearance standpoint. The idea of using jets of air to clean the holes is not new, however, no commercially successful and complete cleaning has been produced by such a method heretofore. It has now been found that a small, exceedingly straight stream or jet, that is, one with a minimum of deflection of all parts of the stream from a parallel path, is required in order to clean the holes with air jets to a satisfactory degree. Only a straight continuous jet is capable of the tearing or cutting action that is necessary to remove a satisfactory amount of the undesired material, since a high percentage of this material is still attached to some degree to the tile body or hole wall. The removal even of loose material, such as dust, also requires a small diameter straight jet since it is essential to avoid interference between the air entering and the air leaving the holes. What attempts have been made, heretofore, using air to clean acoustical tile, have been completely unsatisfactory in all respects.

Prior nozzles for producing air jets did not produce an air stream in which the air maintained a sufiicient parallel or straight path for a suticient distance above tearing action or to avoid mushrooming of the jet which prevents removal even of loose dust. Therefore,

cleaning of acoustical tiles, heretofore, has been accomplished by variations of vibrating and/ or hitting the tiles, a very unsatisfactory method.

A principal object of the invention is to provide a greatly improved method of cleaning drilled acoustical iiberboard tiles. Brieiiy, this method includes the steps of blowing into the holes, at or near the periphery theref, a relatively straight fluid stream or jet of small secto provide theV Amired j States Patent tional diameter at a substantially high velocity, and even further, blowing such jets successively at a plurality of positions around the periphery of the hole.

A further object of the present invention is to provide a nozzle capable of producing the optimum in a straight jet of air, at least for a simple one piece nozzle. Briefly, this is accomplished by constructing the nozzle in accordance with a certain ratio of dimensions as disclosed herein.

A still further object of the invention is to provide a machine for accomplishing the abovesaid methods for cleaning acoustical tile. Briefly, this is accomplished by constructing, in suitable relation to tile carrying means, a plurality of nozzles constructed in accordance with the invention, directed toward the plane of travel of the tiles and disposed so as to blow a straight jet of air into the holes at or near the periphery thereof. The blowing of the Vstraight jets successively at a plurality of positions around the periphery of a hole is accomplished by a novel arrangement of nozzles relative to the direction of travel of the t-ile.

These and other objects and advantages will be apparent when considered in connection with the following detailed description of the preferred embodiment of the invention and the accompanying drawings in which:

Fig. l is a side elevation of a tile cleaning machine built in accordance with and embodying the invention.

Fig. 2 is a plan View of the machine of Fig. 1.

Fig. 3 is a sectional view of a portion of the machine of Fig. 2 taken on line 3-3, showing in section an acoustical tile passing therethrough.

Fig. 4 is an enlarged view similar to Fig. 3 except taken on line 4-4 of Fig. 2.

Fig. 5 is a diagrammatic perspective view of a block having a single acoustical type hole showing theoretically the path of an air jet for cleaning the hole in accordance with the invention.

Fig. 6 is a diagrammatic sectional plan View taken on line 66 of Fig. 4, showing the theoretical positions of the nozzles and jets, relative to a tile hole, at and about which the cleaning operation occurs.

Fig. 7 is a sectional View of a nozzle constructed in accordance with the invention with symbols for designating critical dimensions.

General description Referring now to Fig. l, an acoustical tile cleaning machine 10 is shown which is constructed in accordance with and embodies the invention.

A frame 13, consisting of legs 14, motor supports 1S, air tank supports 16, roller supports 17, dust shield supports 18, tile loading table supports 19, and tile discharge roller `supports 29, provides the means for supporting the various elements of the machine A1t).

ln general, the machine includes two laterally spaced apart, lower, tile-supporting, long-length endless V-belts 2S for carrying, atop the upper reaches thereof, the lateral edges of drilled acoustical fberboard tiles T through the length of machine 10. Drilled holes H, in one face of the tiles T passing through the machine, open downward and pass over three air tanks 26 having a plurality of air nozzles 27 aimed upward therefrom. Two laterallyv spaced-apart, upper, long-length endless V-belts 28 are disposed so that the bottom reaches thereof ride atop the lateral edges of moving tiles T through the length of machine 10, which, due to the weight of rollers 29 resting vertically on V-belts 28, hold down the tiles T in resistance to high pressure air jets from Positive vertical support and lateral positioning of the lower tile-supporting V-belts 25 and lateral positioning of the tiles T and upper V-belts 28 are provided by two grooved elongated belt shoes 35 which are suspended in nozzles 27.

position and afiixed to both the air tanks 26 and the roller supports 17.

Air is supplied to tanks 26 from a manifold 36 through pipes 37. Drive power for both lower and upper V-belts, and 28, is supplied by a motor 3S supported on motorplate 39 by motor supports 15. Dust shields 45, 46, 47, i8 and 49 enclose respectively the top, bottom, sides, front and rear of the central or cleaning portion of machine 10.

Tile driving elements Motor 38, by way of reducer 54, drives a rear lower V-belt sheave drum through chain 56, sprockets 57, 58 and shaft 59. Shaft 59 is rotatably supported at each side of drum 55 in bearings 60 which are mounted on the rearward pair of legs 14. Sheave drum 55 has annular belt grooves 61, one adjacent each lateral edge thereof, shaped complementarily for the reception of lower V-belts 25. A similarly constructed, forward, lower sheave drum 62, with belt grooves 63 for the reception of the opposite extent of lower V-belts 25, is affixed to shaft 64. Shaft 64 is rotatably mounted at end of drum 62 in bearing blocks 65. Blocks 65 are grooved along the top and bottom edges thereof for mounting slidably betwecn flanged block supports 66, 67, which in turn are firmly mounted on side plates 68 supported by loading table supports 19.

Blocks 65 are slidably adjustable rearward and forward, to adjust the tension on lower V-belt 2S, by means of threaded shaft 69 fixed thereto, extending rearward therefrom, each through one of the forward legs 14, and threaded in lock nuts 70 which are tightened thereon against legs 14. A cross member tile loading table 71, in the form of a plate or angle iron, extends across the frontmost portion of the machine, at a vertical height even with the upper reach of the lower V-belts 25.

Also aiiixed on shaft 59 is driver spur gear 75 which engages driven spur gear 80. Gear is affixed on shaft 81, which is rotatably supported in bearings 82 mounted on the rearward pair of legs 14 above bearings 60. Rearward upper sheave drum 83, also similar to the two lower sheave drums, is afiixed on shaft 81, and has belt grooves 84 for the reception of upper V-belts 28. A forward upper sheave drum 85, also similar to the aforesaid sheave drums, having belt grooves 86, is affixed on shaft 87 which is rotatably supported by adjustably mounted bearings 88. Bearings S8 are mounted on a roller support extension 89 having elongated grooves 90 to provide the adjustability in positioning bearings 88, thus providing means for adjusting the tension on upper V-belts 23. A narrow cover sheet or guard 91 is disposed over the spur gear 80 and extends back over the driving mechanism for the take-off rollers described herebelow.

Also mounted and atiixed on shaft 59 is a chain drive sprocket 93 which drives tile discharge rollers 94 by means of chains 95 and sprockets 95. The sprockets 96 are atlixed on discharge roller shafts 97 which are rotatably supported in bearings 98 mounted on discharge roller supports 20. The discharge rollers receive and carry the tile T from the working portion of the machine and any number of such rollers may be provided in accordance with the invention.

Referring now to Fig. 3; an enlarged sectional view, taken on line 3-3 of Fig. 2, shows clearly the relation of certain above described parts at a position within the working or cleaning portion of the machine, it being understood that the opposite side of the machine is constructed substantially the reverse of Fig. 3. A lower V-belt 25 is shown slidably supported and laterally positioned by the elongated belt shoe 35. The belt shoe is supported and fixed relative to the air tanks 26 by L clamps 99, each L-clamp being bolted to one side of an ait tank and bolted to the bottom side of the shoe 35. For even greater stability of the belt shoes, several braces 100, of suitable cast angle strips, are bolted to the roller support 17 portion of frame 13 and bolted to the side face of shoes 35.

A complementary groove 101, for the reception of belt 25, extends throughout the length of a lower protruding portion 102 of shoe 35, the protruding portion 102 being disposed beneath the lateral edge of tiles T as the tiles pass through the machine, so that the two opposite belts 25 (only one shown in Fig. 3) are spaced apart and extend immediately along the edges of the tiles T with a substantial portion thereunder for support. It will be apparent that the above said extreme wide spacing between opposite belts 25 would not be necessary if the holes H of the tiles to be cleaned were not disposed in such close proximity to the tile edges.

Each belt shoe 35 also includes an upper tile positioning protrusion 103 extending throughout the length of each shoe, the spacing between the protrusions 103, of each of the opposite side shoes 35, being the exact width of the tiles T, the arrangement being that the tile edges slide along the inner faces 104 of protrusions 103 so that the tiles are held square and laterally positioned in the machine. It will also be seen, in Fig. 2, that the front ends 105 of protrusion 103 are tapered outward to provide sufficient guiding means to bring into alignment tiles slightly misguided in being fed into the machine. Guides 106 may also be provided on the loading table 71 to laterally position tiles T as the tiles are fed into the machine 10.

Referring again to Fig. 3, the disposition of the lower reach of one of the two upper V-belts 2S is shown, the outer edge of which slides along the inner face 104 of shoe protrusion 103, as does the edge of tile T. The upper reach of belt 2S and the lower reach of belt 25, in Fig. l, may be unsupported.

Rollers 29, extending axially across the machine and normally resting on the two lower reaches of upper V-oelts 28, are maintained in respective longitudinal positions in the machine 10 by a series of interlocking, vertieally-free linkages 110 (Figs. l, 2, 3). Each link 110 includes an inverted L-extension 111 extending upward and then outward, and a cross bar 112 extends between upper-faces of extensions 111 of corresponding opposite laterally disposed links to maintain the lateral alignment of the linkages. A bolt 113, threaded through the adjoining portions of extension 111 and cross bar 112, ex tends downward a distance exactly that necessary to ccntact the roller support 17 to prevent rollers 29 from hitting and misaligning shoe 25 which would otherwise occur in the absence of a tile T at the point below the roller 29.

Tile Cleaning elements For the purpose of more clearly understanding the present embodiment, as shown and described, the description will be directed to a machine for cleaning a tile of one particular form and dimension. The machine 10, in Figs. 1 and 2, is constructed to clean tiles T which are l2 inches square, having 484 holes H, of fr, inch (.l87") diameter, cut, drilled or punched partially therethrough in 22 rows of 22 holes spaced evenly 1/2 inch apart, center to center, throughout the area of the tile with the exception of an edge portion of approximately 1/2 inch therearound. Thus in the machine iii, as shown, approximately three l2 inch tiles would be within the machine between legs 14 at any given time. The above dimensions are included herein only to provide ease in visualizing and understanding the instant embodiment, it being understood that the invention is in no way limited to the sizes of tiles T, spacing of holcs H and could be widely varied as to size of machine 10.

The tile cleaning operation is accomplished, as previously discussed, by a great plurality of small, straight, jets of air of relatively high pressure and high speed. ln accordance with the invention, three air tanks 26 are disposed in spaced positions along and below the path of travel of tiles T. In order to provide suitable removal of the dust containing or polluted air, a spacing in the order of at least six to twelve inches between air tanks should be maintained.

Air, under a pressure of thirty pounds per square inch, is supplied to the air tanks 26 through pipes 37. In order to avoid excessive turbulence of the air in the air tanks and pipes, it is necessary that the air tanks and pipes be of sufficient volume to provide air at an equal rate to all the nozzles 27.

In the present embodiment, a tank having a size of 3 x 3 x 12" and a pipe having a l inside diameter is preferred. A valve 120 in manifold 36 is provided for stopping air flow to tanks 26 at the completion of operation. Any standard air supply system (not shown), capable of providing 30 p. s.4 i. air, supplies air to the high pressure air inlet 121.

A full top view of only the middle of the three tanks 26 is shown in Fig. 2, it being understood that all three tanks are constructed similarly. The tanks 26 are bolted onto cross plates 125 which, in turn, are bolted to air tank supports 16 of frame 13. The air tanks consist of a bottom plate 127, side plates 128, end plates 129 and a top plate 130, all welded at the junctions to provide a unitary, air tight box-like structure. Tanks 26 are bolted to plates 125 by means of angle irons 131 welded to the bottom edge of each end plate 129. Air pipe 37 terminates at a complementary hole 135 in one end plate 129 and an air sealing weld is made thereabout.

In the top plate 130, eighty-eight holes 136, 5%6 inch in diameter are provided for the reception of nozzles 27. Nozzles 27 are constructed in the order of .005 inch greater diameter than holes 136 so that an air seal is provided by the inherent pressure of the press iit therebetween. The holes 136, and thus the nozzles 27, are disposed in four rows 137, namely 137, 137', 137, 137' of 22 nozzles each, the rows 137 extending 90 to the direction of tile'travel, the arrangement being that each nozzle in any one row directs a jet of air successively at holes H of one lengthwise row of tile holes H as the tiles pass thereover, as discussed further herebelow.

Referring now to Fig. 3, and particularly Fig. 4, it will be seen that successive nozzles 27, 27', 2'7", 27 in successive rows 137, 137', 137, 137'" are progressively displaced laterally in the order of .05 inch from the direction of travel of tiles T, the arrangement being that each successive nozzle 27, 27', 27, 27 of any one tank 26 directs a jet at a laterally progressively different zone of the holes H of the tiles T.

The theory behind the successful cleaning in the present inventio-n, which is based on the results of considerable testing, is that jets of air are needed of greatly improved uniformity and straightness, which will not merely mushroom within hole H, but will instead, form and maintain a uniform U-shaped path up one Wall and across the hole bottom face and down the opposite wall for that fraction of a second that the jet is directed toward a zone within and near the wall of the hole H. For a diagrammatic example, Fig. 5 shows a fictitious block 138, which is no part of machine or tile T, and an air jet 139, the path of jet 139 showing the form of the above described U-shaped path which is created in the holes H of the tiles T.

From Figs. 4 and 6 it will be apparent that nozzles 27 and 27 will, when directed toward hole H, always be directed towards a zone of the hole H at or near the side wall of the hole, and thus will each have what might be described as one cleaning station, that is, they will set up, each at its own respective time, one uniform jet or U-shaped path of air going upward into the hole at the zones designated u and y res ectively in Fig. 6 and coming down the opposite wall, whereas nozzles 27 and 27" will each set up two dilferent jets in each hole, one upon being so positioned that the jet is entering the hole area, v and x respectively, and one just before the jet is leaving the hole area, w and z respectively. Thus, theoretically, there are six stations whereatl each hole is cleaned, without actually any stopping thereat, in the course of the progress of the hole over any one tank 26. The six stations are displayed diagrammatically in Fig. 6, all on one hole simultaneously although it will be apparent that only one such station would be receiving the air jet at any one time. Thus, considering the portion of tile shown in Fig. 6 as traveling downward, and that shown in Fig. 4 traveling into the paper, the chronological progression of the stations being cleaned would be first at Lt as hole H is over nozzle 27, at v as hole H first comes over nozzle 27', at w as hole H is about to pass from over nozzle 27', at x as hole H first comes over nozzle 27, at z as hole H is about to pass from over nozzle 27, at y as hole H is over nozzle 27.

As was previously stated, the diculty encountered in cleaning the drilled, cut or punched holes of acoustical tile is unusually great because the material to be cleaned therefrom is oftentimes a unitary, not completely separated portion of the tile material, attached to some degree to the hole wall. A mere turbulence of air in the hole, which would be created in the form of a mushrooming of air if the jet of air were not straight, parallel and uniform, would not provide the cutting type of action required to sever attached but undesirable material. A straight jet proyides a cutting action which is suitable for the removal of such attached material.

Therefore, a nozzle is required, which is simple and small, due to the great number required, which is capable of producing a straight and uniform jet of air. It is readily appreciated that no nozzle could provide a jet of air in which the air proceeded through other than a a straight and parallel course.

provided herein which far surpasses known nozzles in dispensing the optimum in straight jets of air. In Fig. 7, a single nozzle 27 is shown in section with critical dimensions designated thereon. Nozzle 27 includes a long, large bore air inlet or port having a diameter d and an overall length c and a small air outlet or port 141 coaxial with port 140 with diameter a and length b, ports 140 and 141 forming a continuous duct through nozzle 27. 1n the preferred embodiment, the critical dimensions of nozzle 27 are:

However,

It has also been found that the size of the nozzle may be varied widely so long as the dimensions a, b, c and d are always varied proportionately from the above dimensions. Very little, if any, variation in diameter of outlet 141 throughout its extent can be permitted. The dimension c, hereabove, is the least critical, and could be reduced considerably if larger tanks 26 or other means for preventing turbulence were provided. The preferred conical angle a at the innermost extent of inlet 140 is in the order of 30 from the perpendicular or in the order of 60 to the axis and would remain in the order of 60 for all variations in size of the nozzle in accordance with the invention. The allowable variation in this angle has been found to be in the order of plus or minus 10 to provide the optimum straight jet.

The distance between the tips 142 and the face of the passing tile T (Fig. 4) is a further critical dimension for the optimum cleaning eciency. For the particular embodiment of the invention disclosed above, a spacing in the order of 1A inch is required. For larger tile holes, a larger nozzle and a greater spacing between nozzle and tile would be preferred. If the nozzle is too close to the tile, a restriction is created against air leaving the hole. If the spacing is too great, the hole is not cleaned eificiently to the full depth thereof. Furthermore, a frusto-conical nozzle end 143 is essential to avoid deflecting air coming from the hole H into the upward traveling air jet entering the hole H.

It has been stated that three similar tanks 26 are provided in spaced dispositions along the direction of tile travel. Less tanks may be provided and the tile travel speed proportionately slowed, however, the quality of the cleaning is decreased considerably. Undoubtedly, this quality would not be so substantially decreased by the use of one tank, if the same number and arrangement of nozzles were included as are above described as included in the three tanks, however, such a construction would not have the preferred improved susceptabiliy to removal of dust provided by three spaced apart tanks. It will also be apparent that the optimum number of tanks is also dependent on the elliciency of the means employed for drilling, cutting or punching the holes and on the cohesive strength of the material of the tile and thus the difficulty of removing undesired portions. The use of a higher air pressure with a lesser number of tanks has been found to provide the def-'red quality in cleaning, however, with the tiles made from the materials preferred therefor, excessive cutting and tile damage is caused by the excessively high speed, straight air jet.

Dust removal elements The removal of dust-filled air from the machine, although not a part of the invention, is necessary in order to provide a properly over-all cleaned product, as well as to provide suitable working conditions in the vicinity of the machine.

Suitable sheet metal shields 45, 46, 47, 4S and 49 are constructed to enclose the central working portion of the machine 10. Top and bottom shields 45 and 46 are shown by broken lines in Fig. l, and are formed'pyramidi- 5"' cally, tapering to an upper dust outlet 145 and a lower dust outlet 146. High volume suction pumps (not shown) draw the dust-laden air from both outlets 145 and 146. The construction of the assembly of dust shields is not air tight, but instead has sufficient allowancel for air intake at joints and at ports cut out therefrom for fitting about working parts of the machine which extend through the shields.

Operation The specific operation of the individual elements is discussed above and considered to be understandable therefrom. The operation, in general, of machine 1t), includes starting of motor 38, opening air valve 120, starting dust removal fans (not shown) and providing, by hand or other means, feeding of tiles T onto loading table 71 and onto lower \{belts 25. Tiles T are fed into machine 10 with the holes H opening downward and upper and lower V-belts ZS-and Z5 cause the tiles to progress through the machine, and be discharged onto rollers 94. Means will need be provided, hand means or otherwise, for removing discharged tiles` from rollers 94.

Air pressure supplied to tanks 26 causes a straight jet of air to be directed upwards from each 4of the 264 nozzles 27 (4 rows of 22 nozzles in each of three tanks). Each of the 22 nozzle-s 27 in each of the twelve rows correspond and act "h corresponding nozzles of all other rows 137 respectively on one of the 22 holes H in each of the 22 transverse rows of holes in cach tile T. Thus each hole H is acted o-n by l2 nozzles, however, the first respective nozzle encountered on each tank by any given hole H is displaced transversely relatively to one side of the hole, the second nozzle is relatively adjacent but to one side of the center of the hole, the third nozzle is relatively adjacent but to the opposite side of the center of the hole, and the fourth nozzle encountered is relatively .isplaced to the side of the hole opposite to that to which the first nozzle is relatively displaced. Thus the straight jets of air from the respective nozzles enter the holes H at the same relative locations and perform the cleaning by the cutting action of a non-mushroomed flow of air which will occur when the jets are entering the hole H at approximately any of the six stations u, v, w,

x, y or z shown in Fig.' 6. A complete cycle, of cleaning at each of the six lstations would occur three times, once 0 at each tank 26. After completion of three such cycles on the holes H of a fiberboard acoustical tile T, substantially all undesirable material has been found to be removed.

Having, thus, completed a detailed description of a l() preferred embodiment of the invention so that those skilled in the art may practice the same, l. contemplate' that variations may be made without departing from the scope of the invention as defined in the appended claims.

I claim:v l. A nozzle for producing the optimum straight jet of rd material, comprising a large port and a small port coaxial therewith, said ports forming a continuous duct through said nozzle, said small port having a diameter a A and a length b, said large port having a diameter d, said Z0 dimensions having a ratio in the order of a:b:d:.032: .l:.l25, and the inner transverse end of said large port having a frusto-conical taper in thc order 60 to thc axis of said nozzle. g 2. A nozzle for producing the optimum straight jet of 2O fluid material for cleaning undesired material from cavities, comprising a frusto-conical fluid outlet end, a large port, a small port coaxial therewith, said ports forming a continuous duct through said nozzle, said small port having a diameter a and a length b, said large port having a diameter d, said dimensions having a ratio in the order of a:b:d=.032:.l25:.l25, and the inner transverse end face of said large port having a frusto-conical taper in the order 60 to the axis of said nozzle.

3. In combination, a nozzle and air tank for producing the optimum straight jet of air comprising a nozzle having a large port and a small port coaxial therewith, said ports forming a continuous duct through said nozzle, said small port having a diameter a and a length b, said large port having a length c and a diameter d, said dimensions having a radio in the order of a:b:c:d=.032:.125 at least .8752.125, the inner transverse face of said large port having a conical taper in the order 60 to the axis of said nozzle, said nozzle being affixed to and opening at the large diameter port end into an air tank, said air tank having a hollow, interior air reservoir of sufficient volume to eliminate turbulence in the supply air under pressure. 4. The method of cleaning acoustical tile having a plurality of cavity type sound absorbing holes therein, comprising the steps of successively blowing a straight, parallel jet of air into said holes at a plurality of stations, said jet entering said holes at each of said stations adjacent the periphery of said holes and spaced from the center of said holes allowing said jet to travel into said holes at each said station, thence across the end of said holes to the opposite portion of periphery, thence outward of said holes along said opposite portion of periphery.

5. The method of cleaning acoustical tile having a plurality of cavity-type sound absorbing holes therein G0 comprising the steps of successively blowing a straight, parallel jet of air into said holes at a plurality of stations, said jet entering said holes at each of said stations adjacent the periphery of said holes and spaced from the center of said holes allowing said jet to travel into said G5 holes at each said station, thence across the end of said holes to the opposite portion of periphery, thence outward of said holes along said opposite portion of periphery, positioning said tiles relative to said jet of air at successive stations by passing said tile in front of said -iet in a direction perpendicular to said jet, systematically laterally displacing said tile relative to said jet in each successive pass.

6. The method of cleaning acoustical tile having a plurality of cavity-type sound absorbing drilled holes therein, comprising the steps of passing said tiles perpendicularly through a straight jet of air being blown from a straight-jet nozzle, disposing said straight-jet nozzle close enough to the drilled face of said tile that the air jet enters said holes in a substantially straight parallel path but not so close that air leaving said cavity is deflected by said nozzle into said entering air jet, disposing said nozzle so that the entering air jet is at a given zone adjacent the cavity periphery, maintaining the air jet diameter so that the entering air stream is spaced from the center of said holes so that the air jet is caused to follow a path into the holes in a direction generally toward the depth of the holes at said given zone, thence across the bottom of said holes to a zone opposite said given zone, thence outward from said holes at said opposite zone.

7. A machine for cleaning acoustical tile having a plurality of cavity-type sound absorbing holes therein, said machine comprising an air tank, a plurality of straight-jet producing nozzles disposed in one face of said tank, said tank having sucient volume to provide substantially equal air pressure to all said nozzles, belt shoes extending through the cleaning portion of said machine, endless belts disposed in said shoes for supporting and advancing said tiles through said machine and for positioning said tile holes successively over respective nozzles, said shoes and thus said belts being laterally spaced apart and disposed under the edges of tiles being supported thereon, and spaced from said holes of tiles supported thereon, and means for restraining said tiles against movement away from said nozzles, said nozzles being constructed to produce a straight jet of air having a diameter less than half the diameter of said holes, to provide a jet capable of entering said holes adjacent the periphery of said holes and follow a substantially U-shaped path into and thence out of said holes in a continuous, substantially uniform stream.

8. A machine for cleaning acoustical tile having a plurality of cavity-type sound absorbing holes therein, said machine comprising an air tank, a plurality of nozzles disposed in one face of said tank, said tank having sucient volume to provide substantially equal air pressure to all said nozzles, belt shoes extending through the cleaning portionof said machine, endless belts disposed 1.0 in said shoes for supporting and advancing said tiles through said machine and for positioning said tile holes successively over respective nozzles, said shoes and thus said belts being laterally spaced apart and disposed under the edges of tiles being supported thereon and spaced from said holes of tiles supported thereon, and means for restraining said tiles against movement away from said nozzles, said nozzles having a large port and a small port coaxial therewith, said ports forming a continuous duct through said nozzles, said small port having a diameter a and a length b, said large port having a length c and a diameter d, said nozzle dimensions having relative values one to another in the order of the inner transverse end face of said large port having a truste-conical taper in the order of to the axis of said nozzle, and the spacing between said nozzle and the adjacent face of said tiles having a relative value with respect to the other said relative values in the order of .250.

References Cited in the file of this patent UNITED STATES PATENTS 1,018,046 Goldman Feb. 20, 1912 1,280,731 Herr Oct. 8, 1918 1,281,005 Herman Oct. 8, 1918 1,310,107 Zouck July 15, 1919 1,360,265 Capell Nov. 30, 1920 1,448,255 Capell Mar. 13, 1923 1,462,512 Loew July 24, 1923 1,524,851 Wolf Feb. 3, 1925 1,545,253 Hall July 7, 1925 1,711,429 Senn Apr. 30, 1929 2,231,136 Newey Feb. 11, 1941 2,538,445 Derbenwick Jan. 16, 1951 2,633,437 Detjen Mar. 31, 1953 2,660,513 Ball Nov. 24, 1953 2,734,213 Ashford Feb. 14, 1956 FOREIGN PATENTS 39,770 Denmark Feb. 4, 1929

Claims (2)

1. 4. THE METHOD OF CLEANING ACOUSTICAL TILE HAVING A PLURALITY OF CAVITY TYPE SOUND ABSORBING HOLES THEREIN COMPRISING THE STEPS OF SUCCESSIVELY BLOWING A STRAIGHT, SAID JET ENTERINGG SAID HOLES AT EACH OF SAID STATIONS ADJACENT THE PERIPHERY OF SAID HOLES AND SPACED FROM THE CENTER OF SAID HOLES ALLOWING SAID JET TO TRAVEL INTO SAID HOLES AT EACH SAID STATION, THENCE ACROSS THE END OF OUTHOLES TO THE OPPOSITE PORTION OF PERIPHERY, THENSE OUTWARD OF SAID HOLES ALONG SAID OPPOSITE PORTION OF PERIPHERY.
2. 7. A MACHINE FOR CLEANING AROUSTICAL TILE HAVING A PLURALITY OF CAVITY-TYPE SOUND ABSORBING HOLES THEREIN, SAID MACHINE COMPRISING AN AIR TANK, A PLURALITY OF STRAIGHT-JET PRODUCING NOZZLES DISPOSED IN ONE FACE OF SAID TANK, SAID TANK HAVING SUFFICIENT VOLUME TO PROVIDE SUBSTANTIALLY EQUAL AIR PRESSURE TO ALL SAID NOZZLES, BELT SHOES EXTENDING THROUGH THE CLEANING PORTION OF SAID MACHINE, ENDLESS BELTS DISPOSED IN SAID SHOES FOR SUPPORTING AND ADVANCING SAID TILES THROUGH SAID MACHINE AND FOR POSITIONING SAID TILE HOLES SUCCESSIVELY OVER RESPECTIVE NOZZLES, SAID SHOES AND THUS SAID BELTS BEING LATERALLY SPACED APART AND DISPOSED UNDER THE EDGES OF TILES BEING SUPPORTED THEREON, AND SPACED FROM SAID HOLES OF TILES SUPPORTED THEREON, AND MEANS FOR RESTRAINING SAID TILES AGAINST MOVEMENT AWAY FROM SAID NOZZLES, SAID NOZZLES BEING CONSTRUCTED TO PRODUCE A STRAIGHT JET OF AIR HAVING A DIAMETER LESS THAN HALF THE DIAMETER OF SAID HOLES, TO PROVIDE A JET CAPABLE OF ENTERING SAID HOLES ADJACENT THE PERIPHERY OF SAID HOLESAND FOLLOW A SUBSTANTIALLY U-SHAPED PATH INTO AND THENCE OUT OF SAID HOLES IN A CONTINUOUS, SUBSTANTIALLY UNIFORM STREAM.

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