US 2797530 A
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y 9 R. R. GARVER 2,797,530
SLURIATOR Filed Aug. 17, 1954 4 Sheets-Sheet l INVENTOR.
A TTORNEVS July 2, 1957 I GARVER 2,797,530
SLURIATOR Filed Aug. 17, 1954 4 Sheets-Sheet 3 IN V EN TOR Whip- 1 AT TORNEVS July 2, 1957 R, R. GARVER 2,797,530
SLURIATOR Filed Aug 17, 1954 4 Sheets-Sheet 4 IN V EN TOR.
W33 MK ATTORN vs United States PatentOfiice Tatented July 2, 1957 SLURIATOR Hagerstown, Md., assignor to 'Pangborn 'Corporation, Hagerstown, land Application August 17,1954, Serial No. 450,323 9 Claims. (Cl. 51-8) This invention relates to blastin-g machines andparticu- ,larly relates to a method and apparatus for maintaining the abrasive particles which perform the blasting work in suspension during the blast cleaning process.
The present invention constitutes an improvement over such prior mechanisms as that disclosed in U. 8. .Patent 2,576,008 granted November 20,1951 to W. 'I. Gladfelter et al.
In blasting devices of the type disclosed in the above mentioned Gladfelter et a1. patent, the abrasive material is maintained in suspension through agitation of the slurry caused by a continuous circulation of the abrasive-containing slurry through a system of pipes, pumps and valves. Among the disadvantages of this system is the complicated arrangement of mechanically intricate parts which not only increase the cost of manufacture and maintenance but which are also subject tofrequent breakdowns. Furthermore, the pump, valves, etc. require constant flushing with clear water to prevent clogging thereof by the abrasive particles which are constantly passing .therethrough. This requires frequent interrupting of the blasting .process so that this cleaning can take place.
Heret-ofore, attempts were made to overcome the above disadvantages by using a direct flow .of compressed air .to agitate the slurry, such direct flow being provided either through a pipe or tube .provided with minute circular vholes'or through the outlet end of single or multiple pipes. However, all such prior devices caused the abrasive material to settle and build up on certain portions of the hopper walls, the areas of such build-up depending on the fixed position or positions of the pipes and the direction in which they extended.
The above, as well as other disadvantages, have been overcome by the present invention wherein a continuous supply of a compressed fluid such as air is ejected into the slurry from all radial directions substantially parallel to the adjacent walls of the hopper, thereby providing a continuous and complete agitation of the slurry and, at the same time, preventing any accumulation or build-up of abrasive materials on particular portions of the hopper walls.
It is, therefore, one object of this invention to provide for the maintenance within a hopper of a suspension of abrasive material in a slurry in such manner that there is substantially no build-up of the abrasive material onthe hopper walls.
.Another object of this invention is to provide for the maintenance of a suspension of abrasive material in a slurry without the necessity for using a complicated system of pipes, pumps and valves.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Fig. -l is somewhat diagrammatic side view of a machine embodying the present invention, partly in elevation and partly in section.
Fig. 2 is a front view of the machine of Fig. l partly in elevation and partly in section.
Fig. 3 is a fragmentary partly sectional rear view of the machine showing the hopper assembly and the water inlet thereto.
Fig. 4 is a fragmentary side elevational view of a second embodiment of the invention wherein two hoppers are provided.
Fig. 5 is a cross-sectional view of one of the hoppers of Fig. 4 showing it .in association with a blast gun device. Fig. 6 is a sectional view of one of the sluriators embodied in the present invention for the purpose of discharging an agitating fluid into the hopper.
Fig. 7 is a top plan view of the device of Fig. 6.
Fig. 8 is a sectional view of a second form of sluriator.
Fig. 9 is a sectional view of a third form of sluriator.
Referring now in greater detail to the drawings wherein similar reference characters refer to similar parts, there is illustrated a "blasting machine generally designated 10. This machine is generally similar to that disclosed in the aforementioned Gladfelter et a1. patent, and, therefore, except for those parts which are new, need not be described in any great detail here. The machine, generally, comprises a housing or cabinet enclosing a blasting chamber 12 at the bottom of which is provided a conical hopper 14 for holding an abrasive slurry. There is also provided a vision window 16 and armholes 18 with which are associated flexible sleeves 20 terminating in gloves 22. The gloves are provided so that the operator may hold and manipulate the work, or the blast gun, or both, within the machine.
The blast gun nozzle 24 is positioned within the blasting chamber and is connected through a flexible hose 26 and a pipe 28 to a T coupling 30. An air line 32 connects the T coupling 30 to a second T coupling 34. There is also connected to the coupling 34 an air line 36 which leads to the source of compressed air. A suitable valve, not shown, but preferably of the trigger type, is adapted to be interposed in the compressed air line leading to the gun nozzle for the purpose of operating the gun. The third arm of the T 34 is connected to one end of a valve housing 38 having a needle valve 4t} therein. Connected to the other end of the valve housing is a T coupling 42 to which are connected air hoses 44 and 46, as best seen inFig. 3. These hoses 44 and 46 are each connected to an externally threaded nipple, each nipple projecting through a wall at the lower end of the hopper 14, as best seen in Figs. 2 and 3. A compressed airflow-regulator generally designated 47, and hereinafter referred to as a sluriator is connected to each of these externally threaded nipples within the hopper for a purpose to be hereinafter more fully set forth.
A conduit48, which may be provided with connections to a window wash valve and to a filter cleaning spray device, such as more specifically illustrated in the aforementioned Gladfelter et a1. patent, is provided with a water inlet 50 and with a valve coupling 52 to which is connected a hose 54. This hose 54 is provided with a threaded bushing 56 at its other end, this bushing being adapted to be threadedly connected to one end of a coupling 58 extending through the hopper wall.
A pipe 60, having a threaded bushing 62 at one end, is adapted to be threadedly connected to the other end of the coupling 58 within the hopper. The opposite end of the pipe 60 is integral with a plat-e 64 which has an opening 66 coinciding with the end of the pipe 60. This pipe 60, having its outlet at 66, is used for replenishing the hopper 14 with fresh water when necessary.
The plate 64 is provided with clamps 68 which retain one end of a hose 70, the outlet portion of this end of the hose being beveled, as at 72. This beveled end of the hose 70, which extends into the abrasive slurry in the.
hopper 14, is, therefore, supported on the plate 64 which is, itself, supported by pipe 60. The opposite end of the hose 70 is coupled, as at 74, to the gun nozzle 24.
Referring now more specifically to the air flow regulators or sluriators" generally designated 47, each of these sluriators is, as described above, mounted on an externally threaded nipple extending through the hopper wall. Each of these nipples is designated 76 and, as best shown in Fig. 6, is held in position on the hopper wall by means of a nut 78 bearing against a washer or washers 80 held against the external surface of a wall of hopper 14.
At the internal end of the nipple 76, within the hopper, is provided a plate 82 which is preferably circular and which has a centrally depending portion 84. The portion 84 is provided with a centrally positioned, internally threaded bore 86. At the upper end of the bore 86 is provided a counterbore 88 forming a central recess in the plate 82. The nipple 76 is threadedly engaged within the bore 86 and supports the plate 82 upon a resilient washer 90 made of rubber or the like, which is interposed between the depending portion 84 and the internal wall surface of the hopper 14.
Connected to the plate 82 in spaced face-to-face relationship is a second plate 92 which is provided with a central recess 94 in opposed relationship to recess 88. A fine, mesh wire screen 96 is positioned between the two plates 82 and 92 which are clamped together by means of bolts 98 and nuts 100.
In the operation of the sluriators, a fluid under pressure, such as compressed air, is supplied through the nipple 76 and flows through the recess 83 into the slot 102 formed between the plates 82 and 92 and in which the screen 96 is positioned. The screen acts as a battle I to diffuse the compressed air in the radial plane, this air being then emitted peripherally from the sluriator in all radial directions which are generally parallel to the adjacent wall surfaces. This radial stream of compressed air acts to agitate the mixture of water and abrasive forming the slurry and, thereby, acts to keep the abrasive in suspension so that it may be properly delivered to the blasting gun. The above noted radial emission of the compressed air prevents the accumulation or built-up of slurry in any particular areas of the hopper walls since no one area is subject to any greater part of the air stream than any other area. It should here be noted that the provision of the central pocket formed by recesses 88 and 94 is of special importance since it not only provides an area for equal air distribution but also provides a pocket for collecting any foreign matter that may be carried by the compressed air line and which would tend to clog the apparatus if such a pocket were not provided.
A modified form of the sluriator is illustrated in Fig. 8. The sluriator 104, shown in Fig. 8, is similar to the sluriator 47 described above except that the plate 106 extends radially somewhat beyond the plate 108 and is provided with an upstanding peripheral flange 110. This construction permits the compressed air to flow in a radially inward direction relative to the hopper. In Fig. 9, still another modification of the sluriator is shown at 112. This sluriator 112 is similar to that illustrated in Fig. 6 except that the peripheral flange 114 extends in an opposite direction from the flange 110. The forms of the invention illustrated in Figs. 8 and 9 may be used where it is preferable to have a relatively greater turbulence but where the accumulation of abrasive on the hopper walls is a secondary consideration. The lateral direction of the compressed air stream relative to the slurry and the impingement of the air stream on the hopper walls provides a large amount of turbulence in the slurry and thereby sustains the suspension.
Figs. 4 and illustrate a modification of theinvention which is adapted to be used in conjunction with an apparatus wherein a plurality of blasting guns are used;
The form of the invention illustrated in Figs. 4 and 5 shows an apparatus wherein two separate slurry hoppers, each serving a separate blasting gun, are provided; these hoppers being illustrated at 200 and 202. The water inlet to each hopper may, if desired, be generally similar to that shown in the above described form of the invention, with a hose, similar to that shown at 54 in Figs. 1 and 2, leading to each hopper, and each hose being connected to a pipe, similar to that shown at 60 in Figs. 1 and 2, at the end of which is a clamping plate for the slurry supply hose for the nozzle, similar to that shown at in Figs. 1 and 2. On the other hand, however, the water inlet hoses may be free from any attachment to the nozzle supply hose and, instead, a separate support pipe 204 may be provided in each hopper. Each support pipe 204 is provided with a laterally extending head 206 having an opening therethrough. The nozzle 208 is provided with a slurry supply hose 209 which extends through the opening in the head 206, and into the slurry, as shown at 210. The external end of the support pipe 204 is plugged as at 214. This type of support means may also be used in the first form of the invention having the single hopper.
At the bottom portion of each of the hoppers 200 and 202 are provided a pair of sluriators 216 similar to the sluriators 47. Each pair of sluriators 216 in one hopper are connected to a coupling unit 218 of a valve 220 by flexible hoses 222. The valve 220 is connected by means of an air line 224 to a similar valve, not shown, in the other hopper. This similar valve is connected to the sluriators in the other hopper in the same manner as the valve 220 is connected to its corresponding sluriators. The air valves are all connected by suitable means to a source of compressed air, not shown. The air hose 226, leading to the gun nozzle 208, may be connected to the source of compressed air by any suitable means and a suitable actuating valve may also be interposed in the air line between the gun nozzle and the source of compressed air. Although two hoppers have been illustrated, it is within the scope of the invention to provide as many gun nozzles and as many hoppers as desired.
In the operation of either embodiment of the machine herein disclosed, the maintenance of a compressed air flow through the sluriators provides a constant agitation of the slurry and, therefore, keeps the abrasive particles in suspension at all times.
The blasting gun used here is preferably of the type disclosed in the U. S.Patent to Keefer, No. 2,369,576, dated February 13, 1945. When the blasting gun is to be operated, the operating valve, which is preferably a trigger-type valve, is actuated to open the compressed air line to the nozzle; The flow of the compressed air through the nozzle sets up a partial vacuum within the gun barrel and, thereby, draws slurry through the slurry line from the hopper into the nozzle, where it is directed by the blast of compressed air against a workpiece being treated. Cut-ofl? valve such. as shown at 40 and 220 may be used to cut off flow of the compressed air to prevent accidental actuation of the blasting gun when the machine is notin use, such as when it is being cleaned or when there is no workpiece in position.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed in this invention is:
1. A blasting apparatus comprising a work blasting chamber, blasting means in said chamber for projecting a stream of abrasive particles against a workpiece positioned in said chamber, a hopper for holding a slurry of abrasive particles, means for conducting slurry from said hopper to said blasting means, and agitating means for projecting a fluid under pressure into said hopper for agitating the slurry therein, said agitating means comprising a head provided with a peripherally positioned annular slot adapted to project said fluid under pressure in an unbroken annular pattern, there being a screening material positioned in said slot, said screening material comprising a plurality of openings spaced from each other by webs, the total surface area of said openings being substantially greater than the total surface area of said webs.
2. The blasting apparatus of claim 1 wherein said blasting means comprises a plurality of blasting devices, each of which is in fluid connection with a separate hopper, each of said hoppers being provided with an agitating means, and the agitating means in each hopper being connected to each other and to a common source of fluid under pressure.
3. The blasting apparatus of claim 1 wherein said agitating means comprises at least one annular body having a peripheral slot therein through which the fluid under v pressure is adapted to flow.
4. The blasting apparatus of claim 1 wherein said annular slot extends radially through the peripheral wall of said head.
5. The blasting apparatus of claim 1 wherein said annular slot is intersected by a second annular slot which extends in a plane substantially perpendicular to said first slot, said slots intersecting at a position adjacent the periphery of said head.
6. In a blasting apparatus, an agitating device for maintaining the abrasive particles of an abrasive slurry in suspension therein, said device comprising a pair of relatively flat plates connected to each other in spaced, faceto-face relationship to form a peripheral slot, a central recess on the opposing faces of each of said plates, said central recesses coinciding with each other, a mesh screen positioned between said plates, an opening extending through one of said plates into the central recess on the face thereof, and a conduit positioned in said opening, there being a screening material positioned in said slot, said screening material comprising a plurality of opening spaced from each other by Webs, the total surface area of said openings being substantially greater than the total surface area of said webs.
7. The apparatus of claim 6 wherein one of said plates extends laterally beyond the other of said plates and is provided with a peripheral flange which is laterally spaced from the peripheral Wall of the other of said plates to form a peripheral passage.
8. The apparatus of claim 6 wherein said peripheral flange is provided on the plate having the opening in which the conduit is positioned.
9. The apparatus of claim 6 wherein said peripheral flange is provided on the plate which is opposite the plate having the opening in which the conduit is positioned.
References Cited in the file of this patent UNITED STATES PATENTS 554,299 Parker Feb. 11, 1896 1,433,302 Rothchild Oct. 24, 1922 1,692,948 Moore Nov. 27, 1928 2,292,897 Nielsen Aug. 11, 1942 2,576,008 Gladfelter Nov. 20, 1951 2,613,482 Hamacher Oct. 14, 1952 2,665,035 Schemm Jan. 5, 1954 2,667,015 Berg Jan. 26, 1954 2,678,520 Jewett May 18, 1954 FOREIGN PATENTS 612,200 Great Britain Nov. 9, 1948