U.S. patent number 3,658,257 [Application Number 04/856,983] was granted by the patent office on 1972-04-25 for spray nozzle.
This patent grant is currently assigned to Nordson Corporation. Invention is credited to Alvin A. Rood.
United States Patent |
3,658,257 |
Rood |
April 25, 1972 |
SPRAY NOZZLE
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 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.
Inventors: |
Rood; Alvin A. (Westlake,
OH) |
Assignee: |
Nordson Corporation (Amherst,
OH)
|
Family
ID: |
25324890 |
Appl.
No.: |
04/856,983 |
Filed: |
September 11, 1969 |
Current U.S.
Class: |
239/589;
239/597 |
Current CPC
Class: |
B05B
13/0627 (20130101); B05B 1/042 (20130101) |
Current International
Class: |
B05B
1/02 (20060101); B05B 1/04 (20060101); B05B
13/06 (20060101); A01q 025/04 () |
Field of
Search: |
;239/590.3,599,601,589,597,598,412,602,284,483,468,592,593,594,596,600,591,547 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
122,344 |
|
Jul 1948 |
|
SW |
|
256,735 |
|
May 1964 |
|
AU |
|
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Grant; Edwin D.
Claims
I claim:
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 effective 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 a substantially
spherical dome through which said orifice is cut, said port being
spaced from said dome about four to seven times the diameter of the
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, whereby said 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 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 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 of the 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 is
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
of water per hour at 500 p.s.i.
30. The combination of claim 4 of a size to coat the interior
surfaces of containers of less than 1 inch diameter.
31. The combination of claim 30 having a maximum diameter about
one-fourth inch.
Description
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 break-up 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 invention 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 20 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 co-pending application
of 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.sub.5 taken along the line 11--11 of FIG. 10.
DESCRIPTION OF PREFERRED EMBODIMENTS
The nozzle tips 1-5 incl., shown in different specific forms in
FIGS. 1, 4, 7, 8 and 9, and 10, respectively, shall in this
description comprise that part of each of the several nozzle
assemblies N.sub.1 - N.sub.5, shown in same Figures, which embraces
a conventional, flat-fan, discharge orifice O, having an approach
passage P leading thereto, a novel side inlet port I.sub.1 -
I.sub.3, and a turbulence chamber T.sub.1 - T.sub.5. 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.sub.2 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 (1) longitudinally opposite the approach part P of the
whole internal passage, (2) adjacent an inlet I.sub.1 -I.sub.3 and
(3) also between an inlet and the closed end of the whole internal
passage. These turbulence chambers T.sub.1 of FIG. 1; T.sub.2 of
FIG. 4; T.sub.3 of FIG. 7; T.sub.4 of FIGS. 8 and 9; and T.sub.5 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.sub.1, P-T.sub.2 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 of the inlet port I.sub.1 - I.sub.3, 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 O, would detract from the
excellence of the 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
I.sub.1 - I.sub.3 in this preferred form of my invention are
designed, formed and located 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 I.sub.2, FIGS. 4, 7, 10 and 11, show the principle
of my port design in a form which I prefer. The port I.sub.3, 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.sub.2 is cut in the part 2' of the two-piece nozzle tip 2-2' of
the nozzle N.sub.2, FIG. 4, as shown in FIGS. 5 and 6. The
two-piece nozzle tip of FIG. 4 employs only the side inlet port
I.sub.2 in the "rearward" 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 two-piece tip form as will more fully appear
below in discussing the gauging of the inlet and outlet orifices
I.sub.2 and O 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 of the blank.
The wheel W conveniently has double conical peripheral edge
formations 10 and 11 tapering at 20.degree. 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 L--L 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 O', FIG. 9, and O", FIG. 11. In FIG. 9 the dotted line at
the near side of the orifice O' suggests the boundary effected by
the planar closure of the end of the nozzle tip N.sub.4 by the
plate 17 (FIG. 8). The lateral dimension of the orifices O' and O"
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, I have found and believe that the
orifices O' and O" 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. I 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 O 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 L--L 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 Q. For the same reason the transverse faces 16 of the
inlet port I.sub.2, 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.sub.1 and I.sub.3, 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.sub.1 -I.sub.3 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 15
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. 1 and 2.
To make the inlet orifice I.sub.2 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.sub.1
in the tip 1 first requires that the blank Q' be secured in the
fixture F' wherewith to 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.sub.1 employed in the tip 1. As suggested
in FIG. 1, the inlet port I.sub.1 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 .degree. 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.sub.1 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.sub.1. 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 preferrably 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 O having been cut and gauged by
measuring the flow of air therethrough, as taught above, may be
left open while the inlet port I.sub.1 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.sub.1 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 of which the tip is bonded or brazed in
fixed, fluid-tight engagement. The bottom of the socket closes the
turbulence chamber T.sub.1 in the "rearward" end of the passage
P-T.sub.1. 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.sub.1, and/or
provides a valve seat as mentioned above. See valve V, FIGS. 7 and
10.
The nozzle N.sub.1 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 1/2
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
thirty-seconds 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. 1 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 140.degree.
F. at 600 psi. The tubes were preheated to 270.degree.F. for 1
minute before spraying and baked for 4 minutes at 570.degree.F.
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.degree. as shown in FIG. 1; the nozzle being
inserted or "lanced" the full length of the tube twice. Exact
prescribed film thickness (10-15 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.degree. 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.degree. 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 I.sub.2 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 of the passage P. At the
angle illustrated in FIG. 1, a fine cleaning probe may be inserted
through the passage 33, port I.sub.1 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 of the 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 of the 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.sub.2 comprises the conventional so-called
adapter 40 which integrally embraces the tip-carrier portion 41 in
which the flange of the portion 2, of the two-piece 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.sub.2 the sole inlet of fluid into the
turbulence chamber T.sub.2 and approach passage P. The nozzle
N.sub.2 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.sub.2 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 I.sub.2, turbulence chamber
T.sub.2, both halves of the passage P and the orifice O 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.sub.3 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.sub.2 of the 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 I.sub.2 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 of the carrier radially opposite
port I.sub.2 to obstruct the probe.
The modified form of nozzle N.sub.4 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.sub.4. 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.sub.5 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.sub.5 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 of the tip and the
closure from the forward end of the 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.sub.5. 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 of the 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.
* * * * *