Nova Patents
US3100724A

Device for treating the surface of a workpiece

Abstract

This record has no abstract on file.

US3100724A, drawing sheet 1
Sheet 1 of 8

Term

Term ended

Expired 13 August 1980, 46.1 years ago.

  1. Priority and filed
  2. Granted
  3. Expired
  4. Today

6 claims: 5 independent, 1 dependent

  1. 1
    I claim:1. A device for treating surfaces, comprising a housing, a nozzle in said housing, a hopper in said housing for receiving and retaining solid finely divided material, a mixing chamber communicating with said hopper, an air jet in said hopper dischargeable into said mixing chamber for forcing therein a combination of air and finely divided material from said hopper, conduit means interconnecting said mixing chamber and said nozzle for transmitting said air and finely divided material to said nozzle, a source of air under relatively higher pressure than said combination of air and finely divided material connected to said nozzle for discharge therefrom with said air and finely divided material, and separator means in said housing, said separator means having an inlet for receiving material discharged from said nozzle, an air outlet for discharging air therefrom, and an additional outlet communicating with said hopper for returning said finely divided material to said hopper.
  2. 2
    A device for separating air and a finely divided 40 powder mixed thereto, comprising a substantially cylindrical housing having two radial side walls connecting to an outer circumferential wall, a centrifugal blower at the axis of said housing, an inlet to said housing at said axis for providing said blower with a mixture of air and finely 45 divided powder, guide vanes around said blower 'and interposed between said side walls for directing said mixture outwardly toward said circumferential wall in a rotative pattern, outlet means for said powder in a side wall adjacent said circumferential wall, said outlet means defining 50 an opening extending substantially the entire periphery of said side wall in which said outlet means is located and outlet means for said air, said outlet means for said air being in a side Wall and radially interposed between said first mentioned outlet means and said guide vanes. 55 3. A device as recited in claim 2 including in addition filter means connected to said outlet means for said air. 4. A device as recited in claim 3 in which said substantially cylindrical housing is associated with a chamber having an air inlet, and to which said filter means com60 prises a plurality of filter elements arranged circumferentially around said chamber inlet, whereby at least a portion of the air drawn into said chamber inlet is provided from said filter means. 5. A device as recited in claim 4 in which said cham65 ber includes a hopper, and means interconnecting said outlet means for said powder and said hopper. 6. A device for treating the surface of a workpiece comprising a nozzle, said nozzle having a convergentdivergent contour terminating in an open exit aperture 70 for discharging directly therefrom against an adjacent object, means for supporting a workpiece adjacent said exit aperture of said nozzle, a source of compressed air, conduit means connecting said source of compressed air to said nozzle for discharge from said nozzle, said air 75 being under pressure sufficient to create a supersonic
  3. 3
    3,100,1 sary for use in obtaining a coating. Therefore, the invention not only automatically recirculates the powder, blit also automatically provides powder of the correct size for obtaining the proper coating on the workpiece. Where the coating is metallic, the bottle 35 is provided 5 with a dampening solution, as mentioned herefore, which prevents combustion or explosion of the airpowder mixture. . This solution may be a slow drying resinous solvent. Where a dry lubricant is to be provided on the surface 10 of the workpiece, the dampening solution is replaced with a binder, such as an epoxy resin binder. When applying a dry lubricant, the powder within the hopper of the housing then will be any dry lubricant material desired as -a coating -on the part. This includes all soft, dry 15 lubricants of a -metallic -material, graphite, molydisulphide, and other dry lubricants. The dry lubricants are retained by the -workpiece primarily by the binder and therefore normally are not discharged against the workpiece at supersonic velocities to penetrate the surface of 20 the part. The foot-operated -valve 13 then is not opened the full extent, but only so much as to give a pressure around 75 p.s.i. gage at the -nozzle. Similarly, handoperated valve 22 is -only partially opened. Again, however, the nozzle is manipulated to coat the part with the 25 mixture of the dry lubricant powder and the binder. When a part is treated with dry lubricant arid removed from the housing, it generally then is baked in an oven to cure the binder -and assure that the coating will be retained on the workpiece. In this manner again a supe- 30 rior, thin, uniform, highly adherent coating is obtained. No other means has been found for providing a dry lubricant having such a low coefficient of friction and with the ability to withstand high pressures as the coating providedby this invention. . 35 This invention has still another application, wherein the surface of the workpiece is cleaned rather than being coated. When -this is the case, the dust in the hopper should be in the form of -glass beads of under 300' mesh. No fluid need be provided in bottle 35. The operation of the machine then is as before, the discharge against the part preferably should be supersonic in obtaining the .best results. In cleaning the parts, the nozzle usually is directed against the workpiece at an angle with respect to the surface, which thoroughly cleans the surface without any damage whatsoever thereto. In addition to the cleaning effect it is possible to provide shot peening and the removal of surface strains from the workpiece, in which event the discharge should be more nearly perpendicular to the surface of the part. The use of the fine glass beads provides an ideal cleaning action, but will not result in any coating on the part and will have no· adverse effects on the part. It should be noted that where, glass beads are employed for cleaning the particles do not break down as where other powdered materials are used. Therefore, greater care should be exercised in assuring that the particles placed in the hopper are of the exact size desired. The invention may be used also in applying liquid alone to a part, in which event no powder is supplied to hopper 18 and valve 22 of the secondary supply remains closed. Bottle 35 then is provided with an appropriate liquid to be applied to the part, and the nozzle again is directed to discharge against the surface of the part. Among the liquids which may be used in this manner are polymers such as polytetrafluoroethylene which is marketed by E. I. du Pont de Nemours & Co., Wilmington, Delaware, under the trademark Teflon. In some instances two or more liquids are mixed and applied to the workpiece, in which event the fluid containers are manifolded together as shown in FIG. 6. Here it may be seen that bottles 56 and 57 both connect through lines 58 and 59 with high pressure supply 14, discharging into line 10 through conduits 60' and 61. Valves 62 and 63 are included in the latter lines to control the discharge of 3,100,724 velocity upon such discharge, a source of air and finely divided coating material, said last-mentioned source of air being at a relatively lower pressure than said firstmentioned source of air, said source of air and coating material being connected to said nozzle for mixing there- 5 in with said first-mentioned source of air, whereby when said nozzle exit aperture is directed toward the surface of a workpiece, said finely divided coating material is caused to strike said workpiece at a supersonic velocity and a quantity of said material adheres to said surface jq and forms a coating thereon.
  4. 5
    8. A device for applying dry lubricant to a workpiece comprising a nozzle, said nozzle having a convergent- 20 divergent contour, means for supporting a workpiece adjacent said nozzle, a source of compressed air, conduit means connecting said source of compressed air to said nozzle, said compressed air having a pressure sufficient to create a supersonic velocity upon discharge from said 25 nozzle, a source of air and finely divided dry lubricant material, said last mentioned source of air being in a relatively lower pressure than said first mentioned source of air, said last mentioned source of air and finely divided dry lubricant material being connected to said 30 nozzle for mixing with said first mentioned source of air for discharge from said nozzle therewith, a closed container, and a liquid binder for said dry lubricant material partially filling paid container, said container being series connected in said conduit means upstream of said nozzle, 35 whereby said first mentioned source of air picks up relatively small quantities of said liquid upon passage through said container for securing said dry lubricant material to a workpiece, engaged by the discharge from said nozzle.
  5. 6
    9. A device for treating the surface of a workpiece 40 comprising a nozzle, said nozzle having a convergentdivergent, contour, means for supporting a workpiece adjacent said nozzle, a source of compressed air, conduit means connecting said source of compressed air and said nozzle, said air having a pressure sufficient to create a 45 supersonic velocity upon discharge from said nozzle, a hopper means, a quantity of finely divided solid coating material in said hopper means, a mixing chamber com 8 municating with said hopper means, an air jet in said hopper means dischargable into said mixing chamber for providing in said mixing chamber a combination of said finely divided coating material and pressurized air at a pressure below that of said first mentioned source of compressed air, conduit means interconnecting said mixing chamber and said nozzle for conducting said combination to said nozzle for mixture therein with said first mentioned source of compressed air and discharge from said nozzle with said first mentioned source of compressed air at a supersonic velocity. References Cited in the file of this patent UNITED STATES PATENTS Re. 21,416 Sargent ------.__________Apr. 2, 1940 587,892 Walter______I___________ Aug. 10, 1897 706,701 Thurston______________Aug. 12, 1902 783 ,218 Murray--------------- Feb. 21’ 1905 815,674 Bent---------------__ Mar. 20, 1906 822,379 Luckenbach____________June 5, 1906 878,878 Graupner_____________Feb. 11 1908 1,578,862 Staley--------.--------Mar. 3θ’ 1926 2,119,887 Myers----------------_ June 7 1938 2,123,537 Marr-----------------July 12,1938 2,175,457 Dunn-----------------Oct. 10,1939 2,183,623 Ross ---------------- Dec. 19,1939 2,310,265 Sweeney___:_________ Feb. 91943 2,321,774 Ruemelin-------------june 15’1943 2,403,830 Schneible______________July 91945 2,453,593 Putney________________Nov. 9’1948 2,515,541 Yellott----------------July‘18,’1950 2’^5.542 Yellott-----------------July 18,1950 2,532,655 Backer________________Dec. 51950 2,576,008 Gladfelter et al.________Nov. 2θ’1951 2,618,572 Parrish_______________Nov. jg’J952 2,631,774 Plummer__;__________ Mar. 17*1953 2,666,279 Chalem_______________Jan. 19’ 1954 2,714,563 Poorman et al.____._____Aug. 2’1955 2,744,361 Larsen et al.__________ Mav 81956 2,858,653 Guptill_______________ Nov. 4’1958 2,881,092 Sedlacsik______________7’ 1959 FOREIGN PATENTS 381,591 Great Britain__________Oct. 10 1932 934,037 Germany_______________Oct. 13, 1955 OTHER REFERENCES Scientific American, May 1927, pages 348 and 349.
Independent claims5