US3752400A - Combined spray and anti-clogging means - Google Patents

Abstract

Spray means are described herein which comprise anti-clogging means. The anti-clogging means comprises a device which is positioned upstream of the spray tip and which has a constricted orifice that surrounds a mandrel which has a fluted end that extends past the orifice entrance. The mandrel is slidably mounted in the orifice with a spring to bias it against movement by fluid pressure. Any solids in the liquid that would clog the spray tip are abraded by the action of the mandrel. In a preferred embodiment, the orifice and mandrel assembly is used with airless spray equipment to prevent clogging of the m1nute orifices employed in this equipment and several interchangeable assemblies are used in combination with the several different sizes of orifices used in this spray equipment.

Description

United States Patent 1191 Aug. 14, 1973 Calder COMBINED SPRAY AND ANTI-CLOGGING MEANS [76] Inventor: Oliver Jerome Calder, 1205 E. Madison, Orange, Calif.

[22] Filed: Oct. 4, 1971 [21] Appl. No.: 186,084

Related US. Application Data [63] Continuation-impart of Ser. No. 39,621, May 22, 1970, Pat. No. 3,645,450.

[52] [1.8. CI. 239/116, 239/462 [51] Int. Cl B05h 15/02 [58] Field of Search 230/116, 114, 118, 230/123, 462, 575, 590, 574, 587; 137/244 [56] References Cited UNITED STATES PATENTS 2,776,862 1/1957 Bloom 239/116 3,065,918 11/1962 Hostetter 239/462 X 1,737,945 12/1929 Rigby 239/107 2,613,992 10/1952 Bahnson, Jr. 3,645,450 2/1972 Calder 239/116 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-John J. Love Attorney-Robert E. Strauss [57] ABSTRACT Spray means are described herein which comprise anticlogging means. The anti-clogging means comprises a device which is positioned upstream of the spray tip and which has a constricted orifice that surrounds a mandrel which has a fluted end that extends past the orifice entrance. The mandrel is slidably mounted in the orifice with a spring to bias it against movement by fluid pressure. Any solids in the liquid that would clog the spray tip are abraded by the action of the mandrel. In a preferred embodiment, the orifice and mandrel assembly is used with airless spray equipment to prevent clogging of the minute orifices employed in this equipment and several interchangeable assemblies are used in combination with the several different sizes of orifices used in this spray equipment.

14 Claims, 5 Drawing Figures 1 COMBINED SPRAY AND ANTI-CLOGGING MEANS DESCRIPTION OF THE INVENTION This is a continuation-in-part of my parent application, Ser. No. 39,621, filed May 22, 1970, now U.S. Pat. No. 3,645,450.

This invention relates to the combination of spray equipment and means to prevent clogging of the spray orifice of such equipment and, in particular, relates to such anti-clogging means in combination with airless paint spray equipment.

A major difficulty with all pressured liquid spray equipment is that solids in the liquid are forced into the spray tip orifice and trapped there, clogging the orifice. A commonly used solution to this problem in airless spray equipment is to mount the spray tip in .a rotatable housing so that it can be rotated and the pressure of the liquid can be applied to blow the obstruction from the clogged orifice. This, however, interrupts the spraying.

Similar problems of clogging occur in other industries. To illustrate, orifices of spray nozzles of irrigation equipment or pesticide sprayers, etc., are often clogged during use by solids in the water or liquid being sprayed. The problem, however, is of particular con- FIG. 5 shows an alternate member of the anticlogging means.

Referring now to FIG. 1, the spray device is shown with a conventional spray gun assembly that is provided with a hose inlet 10 for pressured liquid, a hand grip 12 with a valve trigger 14 at a point intermediate its length which is coupled by rod 16 to a spray valve 18. The discharge end from the spray gun has a threaded male end and a spray orifice tip can be attached thereto. As shown, however, the spray gun is attached to a spray boom extension, generally indicated at 24 which comprises a plurality of sections 26 which have threaded female ends for attachment to the discharge end of the spray gun and to the male coupling member shown at 28. These sections comprise an outer sleeve 30 and an inner tubular member 32 in concentric arrangement.

At the terminal end of the boom is positioned a conventional swivel tip spray assembly. This comprises nipple 34 and cap 36 which rotatably support yoke 38 on shaft 40. A fluid passageway which communicates from 'nipple 34, through cap 36 and yoke 38 to the spray cern in the aforementioned airless paint spray equipment where very minute orifices are employed.

It is an object of this invention to provide means in combination with pressure liquid spray equipment that will prevent clogging of the spray orifice.

It is also an object of this invention to provide such means in combination with airless paint spray equipment.

It is an additional object of this invention to provide means whereby such anti-clogging means can be provided with any of a variety of the commonly used airless spray tips.

Other and related objects will be apparent from the following description of the invention.

I have found that the clogging of pressured liquid spray equipment can be prevented by combining with such equipment anti-clogging means that force the fluid to be sprayed through a constricted orifice which surrounds a member that extends slightly upstream of the orifice and that is movably mounted in the orifice with a resilient means to bias it against movement by the force of the liquid pressure. The orifice has a minimal length to prevent it from clogging and either or both of the movable member and the orifice have their opposed surfaces roughened to abrade any solids in the liquid when movement is caused by the applied pres sure and the resilient means.

In particular, I have found that clogging of orifices of spray equipment can be prevented by proper selection of the tolerances and the depth of the roughened surfaces of the aforementioned member and orifice so as to abrade solids in the liquid to a sufficient fineness to prevent their bridging in the orifices of the spray equipment.

The invention will now be described by reference to the figures, of which:

FIG. 1 shows the assembly of the improved spray means;

FIG. 2 illustrates an improved means permitting the facile attachment of the sections of the spray boom;

H68. 3 and 4 illustrate the means for preventing clogging of the spray orifice; and

head mounted on the yoke 38 permits delivery of the pressured liquid to the spray head. A standard cap 44 which is threaded onto nipple 46 secures the spray tip to'the device.

The means for preventing any clogging of the spray tip is shown at 47 in FIG. 1. This attachment is shown in greater detail in FIGS. 3 and 4. The orifice and movable member that prevent clogging are contained within the tubular member 50 which is secured by a cap such as 44 to nipple 46. The spray tip, which includes the spray orifice, is secured to member 50 by cap 51 which is turned onto a male threaded end of member 50.

Referring now to FIG. 2, the detail for the construction of the boom sections 26 is shown in assembly with male coupling 28. The sections comprise an inner conduit 32 which forms the flow passageway for the liquid through the boom. Secured at each end of the conduits is a metal adapter formed from a sleeve 42 with an integral flange 52. The sleeve is bored and tapped at 54 with threads to fit the male end of coupling 28, and

counterbored at 56. The counter bore 56 is enlarged slightly with bore 58 into which is press fitted the end of conduit 32. The tubular sleeve 42 is press fitted into a plastic sleeve 60 which is bored to receive the adapter. The outer sleeve member 30 of the section is mounted on the plastic sleeve 60 in concentric arrangement to the inner conduit 32.

An annular groove 62 is bored in the face of flange 52 to form a seat for the sealing O-ring 64. The O-ring seals against the shank of the male coupling. The coupling has a centrally positioned annular flange 66 which is preferably provided with wrench flats 68 or with a knurled surface to permit gripping of the flange sufficiently to remove the coupling. The boom sections can readily be hand tightened into a leak proof assembly without the need for tools by use of the male coupling 28.

Referring now to FIGS. 3 and 4, the anti-clogging means will be described. The device is shown in assembly with the spray tip as shown in FIG. 1. This subassembly can be attached to the end of the spray boom or can be secured directly onto the spray gun when a boom extension is not needed. Alternatively, the spray tip can be located at the spray gun and can have its discharge end threaded into an end of the spray boom.

The anti-clogging means is contained within tubular housing member 20 which has at its upstream end an annular rim 70 and flange face 72 for engagement against the discharge end of the spray gun by cap 22 or for engagement against nipple 46 by cap 44. An annular washer 118 with a central bore 119 is placed between flange face 72 and the end of the nipple 46 or the threaded discharge end of the spray gun. The opposite end of member 20 is male threaded at 74 for attachment to the boom or for attachment to cap 45 that contains the spray tip. Member 20 is bored at 76 for a portion of its length and then counterbored with a series of bores 78', 80, 81 .and'82. The larger diameter counterbore 82 forms a seat for ring 84 which is placed therein. A second member 83 is mounted in the housing member 20. This second member is in the shape of a mandrel with a shank portion 86 and a base portion 88 of slightly enlarged diameter. The second member is placed in the housing member with its shoulder 90 between its shank and base bearing against the inward face of ring 82. The mandrel has a central bore 92 extending through its base and a portion of its shank and terminating at the intersection with a transverse bore 94. After assembly, the ring 84 is cemented in its seat. Other means to secure the assembly could also be used, e.g., a set screw or spot weld could be used.

The bore 92 is enlarged at 98 to form an annular shoulder 100 against which is seated the upstream end of spring 104. The opposite end of this spring fits into bore 78. The end of the housing member is threaded at 74. Cap 45 is shown secured to threads 74 with the spray tip 124 retained within the cap and bearing against the inside face of the cap. A sealing washer 128 is provided between the base face of the spray tip and member 20. The cap 45 has a central opening 126 which is chamfered towards the discharge end as shown. The spray tip is conventional in construction, e.g., it is formed of a wear resistant material such as tungsten carbide and contains a converging entrance bore 129 that intersects a diverging exit port 127.

The orifices of these pressured, airless spray means are constructed to provide flow rates at specified pressure drops and spray fan widths. The orifices are formed by a tappering'cut 127 into the bulbous tip of the spray head to a sufficient depth to intersect with bore 129. The shape and inclination of the sidewalls of cut 127 as well as the depth of cut 127 into bore 129 and the diameter of this bore determine the flow rate and the spray pattern characteristics of the spray tip.

The orifice sizes of the spray tips are usually specified as equivalent diameters which are the diameters of circular orifices that would give an equal flow of water at the specified pressure drop. The following table summarizes typical flow rates of water at a constant pressure drop and the equivalent orifice sizes:

FLOW RATE (sp EQUIVALENT CIRCULAR ORlFlCE DIAMETER (inch) 0.07 to 0.16 Up to 0.013

0.16 to 0.34 0.013 to 0.019

0.34 to 0.50 0.019 to 0.023

0.50 to 0.93 0.023 to 0.031

The anti-clogging means of the device comprises ring 84 and member 83. Ring 84 forms a constriction, i.e., orifice 77 in the longitudinal flow passageway through the device and this orifice should be of limited length as described hereinafter. The shank end of member 83 is of sufficient length to extend slightly past the face of ring 84 so that it is never flush with this face. It is preferred that at least one of the opposed surfaces of member 83 and orifice 77 be roughened. This can be conveniently provided by flutting or knurling of the shank end of member 83 and the length of this roughened surface should at least extend the entire distance of travel of member 83 in orifice 77 so that a flutted or roughened surface is within orifice 77. Alternatively, the shank portion of member 83 could be smooth and the inside edge of orifices 77 could be could be knurled or flutted. Any suitable means for roughening the surface of one or both of these members can be used, e.g.,the surfaces can be knurled or etched rather than flutted as shown.

In the preferred construction the clearance between the top of the grooves on the shank of member 83 and the inside edge of orifice 77 is maintained at a minimum value, e.g., about 0.0005 inch. Preferably, the shank of member 83 is lapped in the orifice and the tops of the grooves are lapped off. The tops of these grooves then will have a slightly square contour as shown in FIG. 4.

l have found that the depth of the surface roughening should be correlated to the desired discharge rate, i.e., size of the spray tip orifice to achieve maximum efficiency. The depth of this roughening should be sufficient to avoid an excessive pressure drop through the anti-clogging device where the device limits the discharge flow rate through the nozzle. The depth of roughening should also be less than that amount that will cause solids to bridge across the spray tip orifice and clog it. The following are correlations for airless spraying equipment used on typical paints with discharge pressure drops of from 500 to about 5,000 psi.:

Number Flow Rate Equivalent Maximum depth of grooves (gpm) Orifice Dia. of grooves per inch 0.07 to 0.16 0.009 to 0.013 0.003 0.16 to 0.34 0.013 to 0.019 0.006 60 0.34 to 0.50 0.019 to 0.023 0.010 50 0.50 to 0.93 0.023 to 0.031 0.012 to 0.014 40 to 45 Similar correlations can be developed for other flow rates and/or other systems. To illustrate, use of the anticlogging device with spray orifices of greater diameter or for greater flow rates would permit a greater depth of surface roughening. Generally, however, the depth of this roughening is from about 0.001 to about 0.025 inch.

For successful operation, it has been found that member 83 should extend slightly past the annular orifice, the orifice should have a short length, and member 83 should be free for movement in the orifice. For maximum efficiency the length of orifice 106 should be less than about 0.125 inch and, preferably less than about 0.050 inch. It has been found that maximum efficiency of the device when combined in airless spraying system such as described herein is achieved at orifice lengths of 0.010 to about 0.035 inch. When the device was provided with an orifice having a length of 0. 1 25 inch, the device tended to clog. This limitation of length can also be expressed relative to the travel of member 83 in orifice 106. The ratio of orifice length to travel should be kept at a minimum value since when this ratio becomes too high there is a tendency for the member 83 to bind in the orifice. Preferably the ratio of orifice length to travel should be less than about 1.0 and, most preferably, less than about 0.2. In the device shown in FIGS.

3 and 4, member 83 has a diameter of 0.2075 inch and a travel of 0.100 inch. The end of member 83 extends about 0.125 inch past the face of ring 84 when the device is unloaded, i.e., when no pressure is applied to the inlet of the device.

From the preceding description, it can be seen that the member 83 is free for relative movement in its mounting within member 20. The member 83 can move axially or rotationally within its mounting within member 20. The resilient biasing means, spring 104, biases the member 83 against the force of the pressured liquid and against movement so that movement is induced when obstructions in the orifice flow area occur that resist the pressure of the liquid. It is believed that this movement is sufficient to cause abrasion of the obstruction so that any solids are reduced to a fineness sufficient to pass the orifice and the spray tip orifice.

The normal operation of a spray system equipped with the anti-clogging device also induces relative movement of member 83 and ring 84. When the spray valve 18 is opened, the fluid pressure surge against the upstream end face of member 83 will urge it downstream against the bias of spring 104. This is repeated throughout the use of the spray system and causes repeated relative movement of the members and insures that any solids in the liquid are comminuted or abraded before passing downstream towards the spray discharge orifice. It also insures that the solids do not accumulate in the anti-clogging device, i.., insures that the device does not function as a filter.

FIG. 5 illustrates an alternate embodiment for forming the anti-clogging orifice. Sharp edged orifices will maintain the length of the orifice at the minimum value and these sharp edged orifices can be shaped with a chamfered bore. The orifice 101 is shaped with an arcuate chamfer 107. The ring 103 is bored for a portion of its length at 105 and then shaped with the arcuate chamfer 107. If desired, the orifice 101 can be honed to the exact dimension desired.

While the invention has been illustrated in the presently preferred combination with airless spray equipment such as is commonly used in the painting industry, other-combinations can also be used. To illustrate, the anti-clogging device can be combined with the similar spraying means used for the application of pesticides to the soil, plants, buildings, etc. The device can also be used in combination with various irrigation equipment such as sprinkling systems or aqueous fogging systems, the latter useful for frost protection.

The invention has been described with particular reference to the illustrated and preferred embodiments. It is not intended that the invention by unduly limited by this illustration, but rather, it is intended that the invention be defined by the means and their obvious equivalents set forth in the following claims.

I claim:

1. A pressured liquid spray means having a discharge orifice of fixed dimensions terminally positioned in a line with means to supply a liquid under pressure thereto for discharge from said discharge orifice and anti-clogging means therefor positioned at a point in said line upstream of said discharge orifice which comprises:

a housing member having inlet and outlet ends adapted to be connected in said line;

a flow passageway therethrough;

anti-clogging orifice means of reduced crosssectional area in said flow passageway;

a second cylindrical member positioned in said flow passageway and extending through and terminating slightly upstream of said anti-clogging orifice means;

means retaining said second member within said passageway of said first housing member while permitting relative movement between said housing and second members without increasing of the tolerances therebetween; and

resilient means to urge relative movement between said housing and second members in opposition to fluid pressure from said supply, whereby said anticlogging means is operative to abrade any solids contained in said liquid to a fineness permitting their passage through said discharge orifice.

2. The combination of claim 1 wherein said liquid spray means comprises airless spray means and said discharge orifice has a size from 0.009 to 0.043 inch, equivalent circular orifice diameter.

3. The combination of claim 2 wherein said anticlogging orifice has a length no greater than about 0.125 inch.

4. The combination of claim 2 wherein said anticlogging orifice has a length less than about 0.040 inch.

5. The combination of claim 2 wherein at least one of the opposed surfaces of said'anti-clogging orifice and said second member are roughened to a depth from 0.003 to 0.014 inch.

6. The combination of claim 2 wherein said second member is one of a series of interchangeable members having varied depths of surface roughness from 0.003

to 0.014 inch.

7. The combination of claim 1 wherein said anticlogging orifice is a sharp edged orifice having no appreciable length.

8. The combination of claim 7 wherein said anticlogging orifice is formed with an arcuate surface convexly oriented to said passageway.

9. The spray means of claim 1 wherein said housing member is tubular with an axial flow passageway therethrough and said second, cylindrical member is mounted therein.

10. The spray means of claim 9 wherein said second, cylindrical member has a shank portion extending through said anti-clogging orifice means and wherein the shank portion has a roughened surface.

11. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.009 to 0.013 inch and the depth of said surface roughness is no greater than 0.003 inch.

12. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.013 to 0.019 inch and the depth of said surface roughness is no greater than 0.006 inch.

13. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.019 to 0.023 inch and the depth of said surface roughness is no greater than 0.010 inch.

14. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.023 to 0.031 inch and the depth of said surface roughness is no greater than 0.014 inch.

Claims (14)

1. A pressured liquid spray means having a discharge orifice of fixed dimensions terminally positioned in a line with means to supply a liquid under pressure thereto for discharge from said discharge orifice and anti-clogging means therefor positioned at a point in said line upstream of said discharge orifice which comprises: a housing member having inlet and outlet ends adapted to be connected in said line; a flow passageway therethrough; anti-clogging orifice means of reduced cross-sectional area in said flow passageway; a second cylindrical member positioned in said flow passageway and extending through and terminating slightly upstream of said anti-clogging orifice means; means retaining said second member within said passageway of said first housing member while permitting relative movement between said housing and second members without increasing of the tolerances therebetween; and resilient means to urge relative movement between said housing and second members in opposition to fluid pressure from said supply, whereby said anti-clogging means is operative to abrade any solids contained in said liquid to a fineness permitting their passage through said discharge orifice.

2. The combination of claim 1 wherein said liquid spray means comprises airless spray means and said discharge orifice has a size from 0.009 to 0.043 inch, equivalent circular orifice diameter.

3. The combination of claim 2 wherein said anti-clogging orifice has a length no greater than about 0.125 inch.

4. The combination of claim 2 wherein said anti-clogging orifice has a length less than about 0.040 inch.

5. The combination of claim 2 wherein at least one of the opposed surfaces of said anti-clogging orifice and said second member are roughened to a depth from 0.003 to 0.014 inch.

6. The combination of claim 2 wherein said second member is one of a series of interchangeable members having varied depths of surface roughness from 0.003 to 0.014 inch.

7. The combination of claim 1 wherein said anti-clogging orifice is a sharp edged orifice having no appreciable length.

8. The combination of claim 7 wherein said anti-clogging orifice is formed with an arcuate surface convexly oriented to said passageway.

9. The spray means of claim 1 wherein said housing member is tubular with an axial flow passageway therethrough and said second, cylindrical member is mounted therein.

10. The spray means of claim 9 wherein said second, cylindrical member has a shank portion extending through said anti-clogging orifice means and wherein the shank portion has a roughened surface.

11. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.009 to 0.013 inch and the depth of said surface roughness is no greater than 0.003 inch.

12. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.013 to 0.019 inch and the depth of said surface roughness is no greater than 0.006 inch.

13. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.019 to 0.023 inch and the depth of said surface roughness is no greater than 0.010 inch.

14. The spray means of claim 6 wherein said discharge orifice has an equivalent diameter of 0.023 to 0.031 inch and the depth of said surface roughness is no greater than 0.014 inch.

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