US 3658257 A
Improved airless spray nozzles and methods and means for making them. A spray nozzle tip having a central longitudinal passage terminating in an outlet orifice is provided with a single lateral inlet to the passage. The opposite open end of the passage is closed to form a turbulence chamber by means which may be removable or detachable and may be yielding or resilient. The lateral inlet is related in size to the outlet orifice and is in the form of a slot having transverse faces which lie in planes that intersect in a line which lies in a plane normal to the longitudinal axis of the passage. The nozzle tip may be mounted in a carrier. The nozzle tip is readily cleanable by a cleaning probe inserted through the lateral inlet. The nozzle tip is made from a preformed blank having an internal passage by a grinding wheel of the proper shape and size. The effective areas of the inlet and outlet orifices are determined during their cutting by passing air through the passages and measuring the rate of flow from the lateral inlet and from the outlet orifice.
Description (OCR text may contain errors)
United States Patent Rood [ 51 Apr. 25, 11972  SPRAY NOZZLE  Inventor: Alvin A. Rood, Westlake, Ohio  Assignee: Nordson Corporation, Amherst, Ohio  Filed: Sept. 11, 1969  Appl. No.: 856,983
52 U.S.Cl ..239/589,239/597 s11 lnt.CI. ..A0lq25/04  FieldofSearch. ....239/s9o.3,s99, 601,589,597, 239/598, 412, 602, 284, 483,468,592, 593, 594,
FOREIGN PATENTS OR APPLICATIONS 122,344 7/1948 Sweden ..239/589 256,735 5/1964 Australia ..239/547 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Edwin D. Grant Attorney-Bosworth, Sessions, l-Ierstrom and Cain [5 7] ABSTRACT Improved airless spray nozzles and methods and means for making them. A spray nozzle tip having a central longitudinal passage terminating in an outlet orifice is provided with a sin gle lateral inlet to the passage. The opposite open end of the passage is closed to form a turbulence chamber by means which may be removable or detachable and may be yielding or resilient. The lateral inlet is related in size to the outlet orifice and is in the form of a slot having transverse faces which lie in planes that intersect in a line which lies in a plane normal to the longitudinal axis of the passage. The nozzle tip may be mounted in a carrier. The nozzle tip is readily cleanable by a cleaning probe inserted through the lateral inlet. The nozzle tip is made from a preformed blank having an internal passage by a grinding wheel of the proper shape and size. The effective areas of the inlet and outlet orifices are determined during their cutting by passing air through the passages and measuring the rate of flow from the lateral inlet and from the outlet orifice.
31 Claims, 11 Drawing Figures PATENTmmzs I972 3, 658 257 sum 1 0F 3 HY fi MZIM a ATTORNEYS SPRAY NOZZLE SUMMARY OF THE INVENTION An object of my invention is to provide an airless spray nozzle which in a very small size and capacity will produce a more perfect fan pattern, fine atomization and a very quick breakup of the liquid film very close to the outlet orifice at the root of the fan. Such a nozzle makes possible the airless coating of the interior of small tubes and vessels. Another object is to provide a side inlet port for such a nozzle, as well as for larger ones, that is easily cleaned, and is capable of producing more readily a benign turbulence in the fluid stream at, in and/or beyond the discharge orifice.
My invention is also concerned with reducing or preventing clogging of airless spray nozzles, and, colaterally, with cleaning nozzles that have become wholly or partly obstructed. This matter becomes more critical especially in small nozzles that are used to spray paint in which solid or congealable constituents are present. My invention provides a single large" inlet port for the nozzle tip of size and shape having a lesser tendency to clog than the outlet orifice instead of following prior practice of using two or more small" inlet ports. My invention also disposes the nozzle tip in the nozzle structure in a way that freely exposes the inlet port as well as the outlet orifice to cleaning probes and other ways and means to clean the tip.
It is also among the objects and accomplishments of my in vention to provide a new method of making side inlet nozzle tips and also to provide improved closures for such tips as they are employed in complete nozzle assemblies attached to spray guns.
An embodiment of my invention comprises a nozzle tip having an annular wall and a longitudinal passage within the wall open at one end and leading to a discharge orifice at the other end with a lateral inlet port spaced between said ends. The lateral inlet port is cut through the wall in substantially the form of a slot having flat transverse faces which lie in converging planes that intersect in a line that lies in a plane normal to the longitudinal axis of the passage. The bottoms of the slot lie in opposite parts of the wall. The lateral inlet port directs fluid into the passage transversely of the longitudinal axis of the passage. That portion of the passage between the lateral inlet port and the outlet orifice defines an approach passage to the outlet orifice while the portion between the closed end and the approach passage comprises a turbulence chamber.
The method of making my spray nozzle tip from blank stock having a central longitudinal passage open at one end includes the steps of cutting through the end wall of the blank to the passage to make the outlet orifice and measuring the effective size of the outlet orifice while it is being made by causing a fluid under pressure to flow through the orifice and measuring the rate of flow. Further steps include cutting through the side wall of the blank to the passage to make the inlet port orifice, measuring the effective size of that orifice, or the parallel sum of the two, in the same way that the effective size of the outlet orifice is or was measured, and relating the effective sizes of the two orifices to each other according to the relative rates of flow of the fluid therethrough.
BACKGROUND OF THE INVENTION 1. Field of the Invention My invention lies in the field of Sprayers and Spraying Nozzles and relates particularly to the field of spray nozzles of relatively small gallonage delivery as compared with the nozzles for lawn sprinklers and fire hoses. One field, for example, in which nozzles embodying this invention have especial utility, is that of hydraulic airless spraying of paint in flat fan spray patterns in which the sizes of the nozzles are such that the gallonage flow of water at 500 p.s.i. is between about 2 to gallons per hour. My invention also comprehends spray nozzles for spraying liquids and fluids other than paint. One aspect of the field of this invention relates to spraying with fine atomization in small spray patterns with very small liquid films or sheets extending beyond the nozzle orifice. A particular field is spray coating the interiors of small tubes, pipes and vessels having an inside diameter of about one-half inch, for example.
2. Description of the Prior Art As presently informed, the most pertinent prior art comprises the invention or improvements disclosed in the copending applicationof myself and others, Ser. No. 731,062 filed May 22, 1968 and, more remotely, the prior patents and practices referred to in that application. Mention is also made of the Wahlin U.S. Pat. No. 2,745,701 for the conventional teaching about the V-slot discharge orifice in the dome of the nozzle tip and about the approach passage thereto. Pertinent prior art also comprises the prior public use and sale by Nordson Corporation, assignee of my invention, of one or more of the embodiments of the invention contained in my said prior pending application.
These exemplifications of the prior art have taught the use of spray nozzle tips wherein the fluid to be sprayed was forbidden to enter the nozzle tip in the direction of the longitudinal axis thereof. More particularly, the fluid to be sprayed was required to enter the nozzle tip laterally, as by opposing streams meeting in collision near the upstream end of the approach passage, whereby to induce turbulence in that passage. In the prior Carroll U.S. Pat. No. 2,522,928 and Fischer U.S. Pat. No. 1,151,258, both discussed in my co-pending application, see also Danielsson U.S. Pat. No. 1,657,372, the approach passage was substantially non-existent or of such short length, as to fail to function as an approach passage.
In this prior art, lateral inlets to the approach passage were known which intentionally, or by virtue of manufacturing difficulty, induced, or tended to induce, a swirling motion in the fluid stream moving to the nozzle orifice which was detrimental to the flat fan pattern of the spray sought and obtained by my invention.
The prior art has failed to teach ways and means of gaining fine atomization with a very short, almost minute, turbulent liquid film on the atmospheric side of the nozzle discharge orifice especially in small nozzles, has failed to teach the kind and disposition of lateral inlet which I have provided in my present invention, has failed to provide ways and means to prevent clogging, and facilitate cleaning, of nozzle tips and nozzles, and has, among other things that will appear herein, failed to teach methods and means for forming the inlet passage in and/or making or mounting nozzle tips embodying my invention.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a longitudinal section of one of my small nozzles disposed within a small tube in position to spray and coat the interior thereof.
FIGS. 2 and 3 are a side elevation, partly in section, and a front elevation, respectively, of a fixture and cutting wheel for cutting and sizing a side inlet port in the nozzle tip of FIG. 1.
FIG. 4 is a longitudinal section of another form of nozzle embodying my invention comprising an adapter carrying a two-piece nozzle tip and closure.
FIGS. 5 and 6 are side and front elevations, respectively, of a fixture and wheel for holding, cutting and sizing the side inlet in one part of the two-piece nozzle tip of FIG. 4.
FIG. 7 is a longitudinal section of a modified form of my invention mounted on and assembled with the forward end of a spray gun.
FIG. 8 is a longitudinal sectional view of a modified form of the nozzle tip of FIG. 7 with the closure plate of FIG. 7.
FIG. 9 is an isometric view of the nozzle tip of FIG. 8 taken from the upstream end and showing the lateral inlet thereof.
FIG. 10 is a longitudinal sectional view corresponding to the view of FIG. 7 showing however a modified form of nozzle tip and end closure therefor embodying my invention.
FIG. 11 is a top plan view of the rearward part of the nozzle tip T taken along the line 11-11 of FIG. 10.
DESCRIPTION OF PREFERRED EMBODIMENTS The nozzle tips l-S incl., shown in different specific forms in FIGS. 1, 4, 7, 8 and 9, and 10, respectively, shall in this description comprise that part ofeach ofthe several nozzle assemblies N N shown in same Figures, which embraces a conventional, flat-fan, discharge orifice 0, having an approach passage P leading thereto, a novel side inlet port I l and a turbulence chamber T T The two-part nozzle tip in FIG. 4 comprises an orthodox forward part 2, and a separate, novel, rearward part 2 which together embrace the approach passage P and, the turbulence chamber T and the end closure therefor. The term, turbulence chamber, will be used herein, somewhat as in my co-pending application, to designate that portion of the whole internal void or passage in my nozzle tip which is l) longitudinally opposite the approach part P of the whole internal passage, (2) adjacent an inlet I I,-, and (3) also between an inlet and the closed end of the whole internal passage. These turbulence chambers T, of FIG. 1; T of FIG. 4; T of FIG. 7; T of FIGS. 8 and 9; and T of FIG. 10, are the places where violent agitation and, probably gross, directional, turbulence of the fluid to be sprayed is generated and supplied to approach passage P. The whole internal void or passage in each of its specifically different forms disclosed herein may be referred to as the internal passage P-T P-T etc. as the case may be.
I prefer, as shown in each form of my invention, that the whole internal passage taper in cross-sectional area from greater to smaller between the turbulence chamber and the discharge orifice whereby to accelerate the movement of the turbulent fluid stream from the former to the latter. I also prefer that the length of the approach passages P, measured from the center of the dome through which the gash of the discharge orifice O is cut to the nearest aspect ofthe inlet port I l be from about four to seven times the mean diameter of said dome. Improving upon the the invention of my co-pending application, the smaller ratios may be used in a small size nozzle tip as shown in FIG. 1, having a gallonage flow of water at 500 p.s.i. of as little as 2 or 3 gallons per hour.
The turbulence created in the turbulence chamber incident to the vigorous, angled introduction of the fluid thereinto, the abrupt change of direction of the fluid stream from substantially normal to, to parallel with, the axis of the internal passage, and the cut and thrust between the streams entering and leaving the chamber, tends, as I believe, to be gross and directional, probably following discernible gross paths and/or patterns, which, if present at and in the spray orifice 0, would detract from the excellence ofthe fan and spray pattern that is sought to be projected from said orifice. The business of the approach passage is to convert the gross and/or directional kind of turbulence made in the turbulence chamber into, and combine it with upstream turbulence in the approach passage, to create and promote a uniform pattern of minute random turbulent motions with uniform forward velocity across the whole cross-section of the fluid stream adjacent, in and through the spray orifice O.
The work of the approach passage is more burdensome or less burdensome according to the adverse or beneficent influence of the lateral inlet port. Prior to my present invention, side inlets to spray nozzles, intentionally or inadvertently, tended to induce helical or spiral directional swirling of the fluid stream near, at and/or in the nozzle orifice where the core of the inlet stream departed from a true radius of the nozzle tip. The inlets or ports 1 I in this preferred form of my invention are designed, formed andlocated in the tip to introduce fluid into the turbulence chamber with a beneficent influence tending to hasten and enhance the creation of benign, minute random turbulence in the approach passage and at, in and beyond the spray orifice.
The inlet ports l FIGS. 4, 7, l0 and 11, show the principle ofmy port design in a form which I prefer. The port 1 FIGS. 8 and 9, is formed at the end of the nozzle tip 4, and is the more easily illustrated in the isometric view of FIG. 9. It may be formed, however, in substantially the same way that the port I is cut in the part 2 of the two-piece nozzle tip 2-2 ofthe nozzle N FIG. 4, as shown in FIGS. 5 and 6. The two-piece nozzle tip of FIG. 4 employs only the side inlet port I; in the rear' ward part 2 and employs only the discharge orifice O in the forward" part 2. My method of gauging the relative effective sizes of the inlet and outlet orifices is simplified in this twopiece tip form as will more fully appear below in discussing the gauging of the inlet and outlet orifices I, and 0 when the same are embodied in the same tip. Here in FIGS. 5 and 6 the blank Q has its internal void or half-passage P pre-formed therein with no outlet cut through the dome D, nor elsewhere, and as held horizontally in a fixture F with its blind, left as viewed, end firmly secured in a socket S. About half the length of the blank, and the open end of the blind passage is exposed without the fixture to the cutting and slotting action of a diamond cutting wheel W of many, preferably about thirty, times the diameter ofthe blank.
The wheel W conveniently has double conical peripheral edge formations l0 and 11 tapering at 20 from greater radially inward thickness to a narrow right, circular, cylindrical periphery 12. The wheel W is rotated conveniently about an axis a-a in the same plane as, and in this case parallel with, the longitudinal axis LL of the blank Q. The width of the periphery 12 measures the axial dimension of the flat chordal faces 15, FIGS. 9 and 11, and measures approximately the axial dimension of the inlet port orifices 0', FIG. 9, and 0", FIG. 11. In FIG. 9 the dotted line at the near side ofthe orifice 0 suggests the boundary effected by the planar closure of the end of the nozzle tip N, by the plate 17 (FIG. 8). The lateral dimension of the orifices O and 0" depends upon the depth of the cut which the wheel W makes in the blank Q, i.e. how nearly the periphery 12 comes to the diameter of the internal passage. Presently, l have found and believe that the orifices O and 0 may have an approximately square shape about as shown in FIGS. 9 and 11 and function to good advantage.
As shown in FIGS. 9 and 11, the flat faces 15 intersect the adjacent interior side" surfaces of the internal passage in the tip at an acute angle. As presently advised these faces, so disposed, tend to constrict the stream of fluid entering the passage through the port to a smaller transverse dimension, i.e. vena contracta, than the width of the port orifice and the passage. This, I believe, makes room for turbulent fluid to move rapidly and violently from the turbulence chamber past the entering stream into the approach passage. Also, the entering stream is accelerated by constriction to impinge more violently on the surface of the passage opposite the port to induce greater and/or more benign turbulence. I prefer, as shown in all the within forms of my nozzle tip except in FIGS. 8 and 9, that the inlet port be located about midway between the ends of the internal passage and afford a turbulence chamber of volume comparable to the volume of the approach passage. 1 also prefer as shown in all the within forms of my invention that the inlet port be cut transversely across the side of the nozzle tip.
These inlet port orifices, respectively, comprise the sole entrance to the nozzle tip, and have, as I prefer, no smaller minimum dimension nor more restricted configuration than the corresponding discharge orifices 0 whereby to avoid clogging, and thereby starving the discharge orifices. The whole, more particularly the effective, areas of the inlet orifices approximately correspond, respectively, to those of the discharge orifices, plus or minus about 25 percent depending on factors and conditions known to users of the Nordson LV" nozzles disclosed in my said pending application, including gross flow, nature and viscosity of the liquid being sprayed, the spraying temperature and pressure, film thickness desired and the kind of fan and fan pattern desired and the kind of surface being sprayed or coated.
As viewed in FIGS. 5 and 6, the wheel W is mounted above the fixture F so that it cuts a slot 13 into the upper side of the blank Q as the axis a-a is lowered toward the blank. So long as the axis a-a is maintained parallel to the axis LI. and is lowered truly vertically downwardly, as I prefer, the slot 13 will be cut symmetrically into the wall 14 of the blank Q, see FIG. 9, so that flats 15, FIGS. 5, 6 and 9, will be equal, and lie, in this instance, symmetrically related to the approach passage, in substantially the same chordal plane relative to the axis L-L of the blank 0. For the same reason the transverse faces 16 of the inlet port 1 FIG. 11, are equal and are symmetrical to the axis L-L, and intersect in a line which lies in a plane normal to the axis L-L. In the inlet ports I, and I FIGS. 1, 8 and 9, the transverse faces of the slots are not equal but they all lie in planes which meet and intersect in a line which lies in a plane which is normal to the axis of the nozzle.
It presently appears that the angular relation around the axis L-L between the inlet ports I,-I and the discharge orifice O has little influence upon the excellence of the spray pattern which is projected through the orifices, particularly, as long as relationship between the inlet ports, approach passage and turbulence chamber follows my preferences expressed herein. Present experience suggests my preference, however, that one or the other of two apparently optimal angular relations between the inlet port and the discharge orifice be employed. So, in FIG. 1, the overall length of the slot of the inlet port lies at right angles to the overall length of the gash of the discharge orifice. This puts the spray fan longitudinally of the tube 34. In FIGS. 4, 7, 8 and 10 the overall lengths of the ports and orifices are parallel and perform quite well.
Because the diameter of the preferred form of my cutting wheel is much greater than the diameter of the nozzle tip, the arc of the wheel in the slot 13 is nearly flat in respect to the flats 15. Alternatively the axis a-a of the cutting wheel may be given a horizontal right and left motion as viewed in FIGS. 3 and 6 for each increment of downward motion whereby to make the flats l5 truly planar and chordal as well as symmetrical to the internal passage in the tip. Should the wheel be given such right and left motion relative to the tip as the cutting proceeds the axis of the wheel and the axis of the tip should be constrained to move together in a moving vertical, as viewed in FIGS. 3 and 6, plane. This will give a truly transverse cut and will tend to give a desirable true, fine edge to all the sides of the inlet orifice. As shown in FIG. 2, it is more generally accurate to teach that the axes of the wheel and the tip should lie in the same plane, than to emphasize that they be parallel; the latter being incorrect when the inlet port is to be inclined as shown in FIGS. land 2.
To make the inlet orifice I, in the part 2 of FIG. 4 of a particular size, a known type of air gauge hose and/or fitting, not shown, is connected to the exposed open end of the passage P as at 20, FIG. 5, while the blank Q is secured in the fixture F. Then, at intervals between cutting engagements of the wheel with the blank, air is blown into the passage and out through the partially cut slot for the port whilst the flow of air at a predetermined pressure is measured by an appropriate flow meter, not shown. Cutting of the slot is continued until the desired rate of flow of air is obtained. The inlet port then has acquired a particular, determined effective area. Since the outlet orifice O is to be, or has been, cut in the other parts of the tip 2-2, its effective size has been, or can be, gauged and measured in the same way, and related to the effective size of the port exactly as may be desired.
Referring now to FIGS. 1, 2 and 3, cutting the inlet port I, in the tip 1 first requires that the blank 0' be secured in the fixture F wherewithto be worked by the cutting wheel W in much the same way and for the same purpose and effect as described above with reference to FIGS. 5 and 6, having regard for the specific form of the intake port I, employed in the tip I. As suggested in FIG. 1, the inlet port I, is tipped rearwardly away from the nozzle orifice O to accommodate the angled disposition of the tip in the carrier portion 30 of the adaptor 31; the forward face 21 of the port lying substantially normal to the axis of the tip and passage P, and the rearward face 22 being inclined rearwardly about 40 from normal to the axis. This inclination of the port accords with the inclination of the tip in the nozzle and serves to divert the flow of liquid, left to right, as viewed, from the adapter 31 into the passage P at approximately right angles to the axis of the tip and passage whereby to create great, desirable turbulence in the chamber T, and in the passage P.
The fixture F is employed to facilitate cutting the slot in the blank Q to make the inclined inlet port I,. The fixture comprises a base of convenient form and upper structure characterized by a notch 23 to receive the cutting wheel W with generous clearance and to expose the upper surface of the blank Q to the wheel. The fixture F is also characterized by an inclined hole 24 having a smooth cylindrical lower portion with a conical counterbore 28 wherein the body of the blank Q, with its conically tapered forward end 25, is firmly secured by a hollow screw 26 threaded into the tapped upper port 27 of the hole 24.
The blank Q when secured in the fixture has its preformed internal void or passage open at its upper, leftward end, as viewed in FIG. 2, and shown in section in FIG. 1 at its lower, leftward end. The domed terminus of the passage preferrabiy has been slashed to make the discharge orifice O, and the orifice is temporarily plugged while the inlet port is being formed. The hollow screw 26 engages the open end of the blank tip to secure the same in the fixture, and it also provides an airtight air passage to and with the then blind passage in the blank. As in the procedure explained with reference to FIGS. 5 and 6, an air line is connected to the exposed end of the screw 26 as at 20', and the extent of the cutting to form the inlet port is measured by the flow of air at its predetermined pressure to correspond with or relate to, the flow theretofore measured through the discharge orifice, i.e. to the known effective size of the discharge orifice.
Alternatively the discharge orifice 0 having been cut and gauged by measuring the flow of air therethrough, as taught above, may be left open while the inlet port I, is being cut. In this event the desired effective size of the inlet port will be gauged by measuring the flow of air, at its predetermined pressure, into the hollow screw 26 and into the original open end of the blank and passage P and thence out of both the discharge orifice and the, first partially and then completely formed, inlet port orifice in parallel. Knowing the rate of flow of air that the discharge orifice passed at the predetermined pressure, the additional flow will gauge, or permit one to gauge the desired, effective size of the inlet port while it is being formed. I prefer to cut and gauge the discharge orifice in this way before gauging the inlet port in parallel with the discharge orifice as a matter of mechanical convenience; it being more awkward to hold the tip with the finished inlet port freely vented to atmosphere than with the discharge orifice so vented. See FIG. 2. Prudence suggests that the relation between the effective sizes of the inlet and discharge orifices as gauged pneumatically in parallel, be checked as to each orifice when gauged alone in each different size and style of nozzle tip. The sum of the air flow rates measured across each orifice separately in the different specific forms of my invention need not necessarily equal the flow rate through both in parallel.
As shown in FIG. 1 the nozzle N, comprises the nozzle tip 1, adapter 31 as with female threads at its leftward, as viewed end to engage a spray gun or comprise a gun extension, all not shown.
When the adapter 31 functions as a gun extension it may be many times the length shown in the drawing and my enclose a valve stem, of proportionate length and a valve closure element, not shown, adapted to seat on the entrance to the bore 33 and be moved to and from open and closed position by the trigger of the gun. The nozzle also comprises a tip-carrier portion 30, at its rightward end in the inclined socket 32 ofwhich the tip is bonded or brazed in fixed, fluid-tight engagement. The bottom of the socket closes the turbulence chamber T, in the rearward end of the passage P-T,. The hollow body of the adapter is necked down to the axially aligned, short, small bore or channel 33 which intersects the socket 32 and leads fluid to the inlet port I,, and/or provides a valve seat as mentioned above. See valve V, FIGS. 7 and 10.
The nozzle N, is especially adapted to be made in small sizes for use in spraying the interior of small tubes and vessels such as the tube 34 of FIG. 1. For instance, the tube may be from about /1 inch to 1 inch inside diameter and the nozzle only about one-fourth inch outside diameter. The inclined upper face 35 of the carrier 30 permits the tip to protrude comfortably beyond the socket 32 without extending beyond the one-quarter-inch projected cylindrical envelope of the adapter. In this arrangement the edges 36 of the spray fan pattern, shown in dotted lines, clear the carrier freely, and the liquid film at the root of the atomized fan is atomized so quickly that the film extends no more than about three thirtyseconds inch as indicated by the dotted line 37. This permits the spray fan to be well distributed and fully atomized before reaching the interior surface of the tube 34 for the beneficent painting or coating thereof.
To coat the interior of such a tube it is rotated rapidly, and the nozzle inserted into, and then withdrawn from, the tube at noticeable speed. Spraying is preferably being confined to the entrance stroke. Presently incomplete experimental tests for applying lacquer internally to 1 inch inside diameter tooth paste type tubes about 7 inches long, necked down, closed and screw capped at the far end, show that my nozzle in the form shown in FIG. I is probably the first nozzle, air-spray or airless, to effect entirely satisfactory and successful internal coating of such tubes. On these tests, lacquer of 23.5 sec. viscosity by Ford 4 millimeter cup at ambient temperature was sprayed at 140F. at 600 psi. The tubes were preheated to 270F. for 1 minute before spraying and baked for 4 minutes at 570F. after spraying. My nozzle provided good atomization at the above mentioned low temperature and pressure without excessive reduction of the lacquer. Excellent coverage of the whole interior of the tube including the sloping area and neck was obtained with the tip inclined at 60 as shown in FIG. 1; the nozzle being inserted or Ianced" the full length of the tube twice. Exact prescribed film thickness (-15 microns) even in the difficult places was obtained and maintained on a plurality of successively coated tubes; objectionable heavy build-up at any place being avoided, and no objectionable bubbling occurring upon baking. A noticeable economy of material was obtained. Over-spray was reduced, if not wholly eliminated, and no plugging of the nozzle plagued the test operations.
While the nozzle tip is shown to be inclined about 60 to the axis of the nozzle, and tube, my invention in this form contemplates that the axis of the tip and socket may be angled from about 90 to the axis of the nozzle down to an acute angle.
, Throughout such a range, the inlet port will be inclined correspondingly, from right angles like 1 in FIGS. 4, 7 and 10, to the limit of practicable inclination as the tip is inclined more acutely than shown in FIG. 1. Throughout the range of more acute inclinations of the tip to the axis of the adapter, my present understanding is that the inlet port should relate to and coact with the passage 33 to introduce liquid to the passage P at substantially right angles to the axis ofthe passage P. At the angle illustrated in FIG. 1, a fine cleaning probe may be inserted through the passage 33, port I and out through the nozzle orifice O. The angle of the fan pattern between the dotted lines 36 may also be varied by the known techniques of selecting the shape and depth of the gash through the dome of the tip.
In FIG. 1 the nozzle tip is secured by metallic bonding or adhesive attachment between the shank ofthe tip and the socket of the carrier. Compare the prior conventional attachment between the enlarged annular flange on the tip and the counterbore in the carrier as in FIGS. 4 and 7 for example. Attachment ofthe tip in the socket gives a double benefit: a large bonding area, and a closure for the turbulence chamber.
In FIG. 4, the nozzle N comprises the conventional socalled adapter 40 which integrally embraces the tip-carrier portion 41 in which the flange of the portion 2, of the twopiece tip 2-2' is brazed and secured in the counterbore 42. The portion 2 of the tip is carried and secured in the central bore 43 of the externally threaded, longitudinally perforate, as at 44, screw element 45, having threaded engagement with the adapter as at 46. The screw is forcibly movable axially with the axis of the bore 43 aligned with the axis of the carrier whereby to align the axes of the two parts of the tip and corresponding parts of the passage P. Forward movement of the screw carries the rearward part 2 of the tip into fluid-tight contact with the forward part 2, completes the passage P and makes the port I, the sole inlet of fluid into the turbulence chamber T and approach passage P. The nozzle N is detachably secured to the forward end of a liquid or paint gun by a hollow nut 47, see also FIGS. 7 and 10. Liquid or paint to be sprayed flows slowly from the gun through the perforations 44 in the screw to the inlet port I; where it is accelerated to, or about to, the discharge velocity from the orifice O. In this form of my invention cleaning of the nozzle tip is greatly facilitated. Removal of the screw and portion 2' of the tip from the adapter exposes the port 1 turbulence chamber T both halves of the passage P and the orifice 0 all to cleaning by probes and solvent with entire facility. As will more fully appear below, new facility for cleaning the nozzle tips is also provided in the nozzles shown in FIGS. 7-11.
The nozzle N of FIG. 7 comprises the tip 3, secured in the counterbore 52 in the carrier 51 having a flange portion 50 and a resilient rubber-like ring 55 compressed between the flange 50 and the forward face of the end of the gun G which seals the chamber between the gun and the tip from leakage to atmosphere. A nut 57 threaded on the end of the gun and bearing on the flange forces the carrier and tip rearwardly compressing the ring and sealing the chamber, and constraining the open rearward end of the tip into fluid-tight sealing contact with the forward planar face of the closure or turbulence plate 17 bonded to and/or carried in the central yielding perforate web 53 of the ring 55. Holes 54 in the web conduct fluid under pressure from the valve V of the gun to the inlet port I: ofthe nozzle tip; fluid pressure in the chamber between the valve and the port tending to augment the seals against leakage between the plate and the tip as well as between the gun and the carrier.
The carrier and tip are readily removed and exposed for cleaning. The passage P is wide open at the big, rear end, and the nozzle orifice O is freely exposed internally and externally for washing, probing and air blasting. Novel also is the flush disposition of the inner face of the flange 50 in relation to the port 1 to permit a probe to be freely inserted in the port without interference from the flange. When the carrier and top are removed there is substantially no portion ofthe carrier radially opposite port I to obstruct the probe.
The modified form of nozzle N suggested in FIGS. 8 and 9, to which reference has been made above, may incorporate the tip 4 with all the other elements of FIG. 7 and have substantially the same mode of operation and advantages, regard being had for the smaller turbulence chamber T, The nozzle tip 4 and closure turbulence plate 17 may also be substituted in the combination shown in FIG. 4 for the two-piece tip 2-2', the tip 4 replacing the tip portion 2, and the plate 17 being carried on the forward face of the screw 45 whereby to close the open upstream end of the tip 4. In this substitution the need to align the halves of the passage P will be eliminated and the cleaning of the tip 4 will present no greater problem than the tip 2 and carry its own inlet port besides.
The modified form of my nozzle N shown in FIGS. 10 and 11 corresponds considerably to the form of FIG. 7, particularly to the gun, coupling nut and carrier which bear the same reference characters; the nozzle tip 5 being the same as the tip 3 of the FIG. 7 except that it may be longer to accommodate the different form of closure 60 for the rearward end thereof. In the nozzle N the sealing and spacing ring has no central web and preferably, may otherwise correspond to the ring 55 for its resilient, rubber-like qualities to seal the chamber between the gun and the carrier, and space the rearward part ofthe tip and the closure from the forward end ofthe gun.
The ring 65 and the ring 55, as well as the closure 60 may be made of an elastomer or other materials chosen for their particular purposes and with regard to the kind of fluids to which they are to be exposed. Rubber, Neoprene, Polypropolene, Nylon and Delrin exemplify such materials. The closure 60 is preferred to have a snug stretched, resilient fit and have strength in shear to resist being extruded into the turbulence chamber T The ring 55, FIG. 7, yields resiliently in compression and has internal shear strength, as found in O-rings and piston cups, to resist deleterious extrusion into the gaps from which the fluid under pressure must be excluded and also brings the plate 17 into simultaneous sealing contact with the rearward end of the tip. The ring 65 on the other hand has no double sealing chore and can be as unyielding as brass or steel given appropriate sealing surfaces, to engage the flange of the carrier and the end of the gun.
Cleaning the tip 5 while it is secured in its carrier 50 is as easy as cleaning the tip 3, FIG. 7, after the closure 60 has been removed from the end ofthe tip.
While I have illustrated and described certain preferred and modified forms and embodiments of my invention and the best modes presently contemplated by me for carrying out my invention, changes, equivalents, and improvements will occur to those skilled in the art who come to understand and enjoy my invention without departing from the essential principles and precepts thereof. Therefore I do not want my patent to be limited to the forms, embodiments and modes herein specifically illustrated and described, nor in any manner inconsistent with the progress by which my invention has promoted the art.
1. A spray nozzle tip having an internal passage closed at one end and having a spray orifice leading from the passage at its other end and having a side wall of appreciable thickness, a single side inlet to said passage spaced from said other end cut transversely through said side wall, said inlet having an effec' tive area of opening into said passage equal to the effective area of said spray orifice plus or minus about 25% and having substantially planar transverse faces tending to direct fluid into said passage at right angles thereto.
2. A spray nozzle tip comprising an approach passage leading to a spray orifice in one end and having an axis, a coaxial turbulence chamber at the other end, and a single side inlet port for the nozzle tip adjacent said chamber, said inlet port having planar faces disposed transversely of said axis and having an effective area of opening into said passage equal to the effective area of said spray orifice, plus or minus about 25 percent.
3. The spray nozzle of claim 2 wherein said faces lie in planes which meet in a line that lies in a plane substantially normal to said axis.
4. In combination, a spray nozzle tip and a nozzle body, said nozzle tip having an approach passage at one end, a turbulence chamber at the other end, and a single side inlet port between said chamber and said passage, said nozzle body having an axis and an internal passage, and having a socket at the downstream end of said body, said socket being inclined with respect to the axis and embracing said nozzle tip with said inlet port communicating with said internal passage.
5. A spray nozzle tip having an axis, an outlet orifice aligned on said axis at one end, a coaxial turbulence chamber at the other end, and a single side inlet port spaced from said orifice and having an effective area equal to the effective area of said outlet orifice plus or minus about 25 percent and having one face disposed transversely of said axis adjacent said turbulence chamber.
6. A spray nozzle tip having an axis, an outlet orifice aligned on said axis at one end, a coaxial turbulence chamber at the other end, a single side inlet port spaced from said orifice and having one face disposed transversely of said axis adjacent said turbulence chamber, and a coaxial approach passage between said port and said orifice, said passage having asubstantially spherical dome through which said orifice is cut, said port being spaced from said dome about four to seven times the diameter ofthe said dome.
7. The nozzle tip of claim 6 in combination with a nozzle body having an internal passage, an axis, a forwardly disposed socket inclined with respect to said body axis and embracing said tip with said port communicating with the internal passage in said body and with said outlet orifice opening beyond the socket.
8. An airless spray nozzle tip having an annular wall of appreciable thickness, an internal longitudinal passage within said wall leading to an outlet orifice, said tip having a longitudinal axis and a lateral inlet port for said passage spaced from said outlet orifice and comprising an inlet orifice cut through said wall; said port comprising a slot having flat transverse faces which lie in planes that intersect in a line which lies in a plane substantially normal to said axis and having the bottoms of said slot in opposite parts of said wall, said port directing fluid into said passage transversely of said axis and having an effective area equal to the effective area of said outlet orifice plus or minus about 25 percent; the part of said passage between said port and said outlet orifice comprising an approach passage for the outlet orifice and the rest of the passage comprising a turbulence chamber.
9. The nozzle tip of claim 8 wherein the bottoms of the slot in the opposite parts of said wall are substantially flat and are symmetrically disposed relative to said line, and intersect the internal surface of said wall sharply at an acute angle.
10. The nozzle tip of claim 8 wherein the inlet port has no smaller minimum dimension than said discharge orifice, wherebysaid inlet port has no more tendency to clog and become obstructed than said discharge orifice.
11. An airless spray nozzle tip having a gallonage flow of water at 500 p.s.i. as little as about 2 or 3 gallons per hour and having an annular wall of appreciable thickness, an internal longitudinal passage within said wall terminating in one end in a dome having an outlet orifice slashed therein, said tip having a longitudinal axis and a lateral inlet port for said passage spaced from said outlet orifice no more than about four to seven times the diameter of said dome, said lateral inlet port comprising an inlet orifice cut through said wall in the form of a slot having flat transverse faces which lie in planes that intersect in a line which lies in a plane substantially normal to said axis and having the bottoms of said slot in opposite parts of said wall, said port directing fluid into said passage transversely of said axis, the part of said passage between said port and said outlet orifice comprising an approach passage for the outlet orifice and the rest of the passage comprising a turbulence chamber.
12. An airless spray nozzle tip having an annular wall of appreciable thickness, an internal longitudinal passage within said wall leading to an outlet orifice, said tip having a longitudinal axis and a lateral inlet port for said passage spaced from said outlet orifice and comprising an inlet orifice cut through said wall, said port comprising a slot having flat transverse faces which lie in planes that intersect in a line which lies in a plane substantially normal to said axis and having the bottoms of said slot in opposite parts of said wall, said port directing fluid into said passage transversely of said axis and influencing the stream of fluid entering said passage to be transversely constricted and made smaller than the width of said passage at the port and providing longitudinal avenues for turbulent fluid to flow from the turbulence chamber into the approach passage.
13. The nozzle tip of claim 12 in which said turbulence chamber has about the same volume as said approach passage.
14. In combination, a spray nozzle tip and a nozzle body, said nozzle tip having an internal passage closed at one end and having a spray orifice leading from the passage at its other end and having a single side inlet to said passage spaced from said orifice, said nozzle body having a socket embracing said nozzle tip exteriorly of said one end and closing said end, said nozzle body also having a passage leading to said side inlet.
15. In combination, a spray nozzle tip and a nozzle tip carrier, said tip having an internal passage closed at one end and having a spray orifice leading from the passage at its other end and having a single side inlet to said passage spaced from both said ends, said tip being attached to said carrier adjacent said spray orifice, said carrier being spaced away from said inlet and having substantially no portion disposed radially opposite said inlet.
16. An airless spray nozzle assembly adapted to be removably secured to the forward end ofa spray gun, comprising a nozzle tip having a spray orifice at its forward end and having an internal passage open at its rearward end and leading to said spray orifice and having a lateral inlet port in the middle of the side thereof, and a nozzle tip carrier in which a forwardly disposed portion of said tip is secured and said carrier having its rearmost portion substantially flush with said inlet orifice.
17. The spray nozzle assembly of claim 16 wherein the said end of said gun and said carrier are adapted to be aligned and spaced apart to comprise the rearward and forward ends of a chamber for fluid under pressure passing from the gun to the inlet port of said nozzle tip, with means for spacing said carrier from the said end of said gun and enclosing said chamber.
18. The nozzle assembly of claim 17 with attaching means for securing said carrier and said spacing means to said gun in fluid tight engagement therewith.
19. The nozzle assembly of claim 18 wherein the said rearward end of said nozzle tip is disposed in said chamber with means for detachably closing said passage at the rearward open end thereof carried by said spacing means.
20. The nozzle assembly of claim 19 in which said spacing means has a perforate resilient web adjacent the rearward end of said tip comprising said closing means.
21. The nozzle assembly of claim 16 with a closure for the rearward end ofthe tip detachably carried thereby.
22. The nozzle assembly of claim 21 with a sealing ring adapted to be disposed between said carrier and said gun and forming a chamber enclosing the rearward end of said tip and said closure and conducting fluid from said gun to said inlet port.
23. An airless spray nozzle adapted to be removably secured to the end of a spray gun, comprising a nozzle tip having a forwardly disposed part with an internal passage and a spray orifice leading herefrom at its forward end and having a rearwardly disposed part with an internal passage and a side inlet port therefor, a nozzle tip carrier in which said forwardly disposed part is secured, and means supporting said rearwardly disposed part for joining and separating said parts.
24. The nozzle tip of claim 1 including two pieces having a common longitudinal passage, a discharge orifice in one piece and a side inlet port in the other piece.
25. A spray nozzle tip having an annular wall of appreciable thickness, an internal passage within said wall closed at one end and having a spray orifice at its other end, a single side inlet to said passage cut through said wall transversely of said passage between said ends and having an effective area equal to the effective area of said spray orifice plus or minus about 25 percent, said inlet having substantially flat bottoms in transversely opposite parts of said wall that intersect the internal surface of said wall at acute angles and tend to construct the entering stream transversely.
26. An airless spray nozzle assembly adapted to be removably secured to the forward end of a spray gun comprising a nozzle tip having a spray orifice at its forward end and having an internal passage open at its rearward end and leading to said spray orifice and having a lateral inlet port between said open end and said spray orifice, a nozzle tip carrier in which a forwardly disposed portion of said tip is secured, means for spacing said carrier and nozzle tip from said end of said gun and defining a chamber for fluid under pressure between said gun and said inlet port, the rearward end of said nozzle tip being disposed in said chamber and spaced from said gun, and a removable closure for closing the rearward end of said passage and disposed to be pressed against said end by the static pressure of fluid in said chamber.
27. The nozzle assembly of claim 26 wherein said closure 15 yieldably supported in said chamber by said spacing means, and is yieldably engaged by the rearward end of said nozzle tip.
28. An airless spray nozzle tip having a flow rate of water less than 20 gallons per hour at 500 p.s.i. and having an internal passage closed at one end and a spray orifice leading from the passage at its other end and having a side wall of appreciable thickness, a single side inlet to said passage spaced from said other end cut transversely through said side wall, said inlet having substantially planar transverse faces tending to direct fluid into said passage transversely thereof.
29. The nozzle tip of claim 28 having a flow rate of 2 to 3 gallons ofwater per hour at 500 p.s.i.
30. The combination of claim 4 of a size to coat the interior surfaces of containers ofless than 1 inch diameter.
31. The combination of claim 30 having a maximum diameter about one-fourth inch.