U.S. patent number 3,907,207 [Application Number 05/495,267] was granted by the patent office on 1975-09-23 for atomizing sprayer device.
Invention is credited to John W. O'Brien.
United States Patent |
3,907,207 |
O'Brien |
September 23, 1975 |
Atomizing sprayer device
Abstract
A hand held liquid sprayer for producing an atomizing mist
includes an air and liquid control body attached to a spray head.
The spray head contains an internal mixing chamber into which
liquid and pressurized air are directed through respective liquid
and air passages extending through the body and into the head. A
circular spray tip in the mixing chamber directs the liquid
radially outward into a perpendicular collision with high velocity
air entering the chamber through a thin annular slot. The
perpendicular impact of the expanding air breaks the liquid up into
small particules which are then completely atomized by a further
expansion as the mixture is sprayed through a nozzle. A staggered
valve assembly operates in sequence to open the air passage before
the liquid passage is opened and to close the liquid passage before
the air passage is closed. A modification of the hand held liquid
sprayer includes a second air passage to provide a separate blast
of air prior to the beginning of the liquid spraying. The valve for
the second air passage closes as the liquid valve is opened. A
spray head for use in a fixed position includes a poppet valve
which closes the liquid passage in the absence of air flow. The
spray head is securable to a second identical spray head such that
the same air and liquid inlet lines supply both spray heads and the
two nozzles spray in opposite directions.
Inventors: |
O'Brien; John W. (Harrison,
AR) |
Family
ID: |
23967966 |
Appl.
No.: |
05/495,267 |
Filed: |
August 7, 1974 |
Current U.S.
Class: |
239/415;
239/416.4; 239/432; 239/417.3; 239/434; 239/528 |
Current CPC
Class: |
B05B
7/1209 (20130101) |
Current International
Class: |
B05B
7/02 (20060101); B05B 7/12 (20060101); B05B
007/12 (); B05B 007/04 () |
Field of
Search: |
;239/123,288,288.3,289,295,310,398,414,415,416.4,416.5,417.3,431,426,432,433,434 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Ward, Jr.; Robert S.
Attorney, Agent or Firm: Lowe, Kokjer, Kircher
Claims
Having thus described my invention, I claim:
1. Spraying apparatus for use with a liquid source and a
pressurized air source to produce a fine liquid spray, said
apparatus comprising:
a spray head having an air-liquid mixing chamber therein;
liquid delivery means interconnecting said spray head and said
liquid source;
air delivery means interconnecting said spray head and said air
source;
a liquid passage disposed through said spray head for directing
liquid from said liquid delivery means to said mixing chamber, said
liquid passage including a central liquid discharge orifice to said
mixing chamber;
an air passage disposed through said spray head for discharging air
from said air delivery means to said mixing chamber, said air
passage including a circular discharge annulus to said mixing
chamber concentrically disposed with respect to said liquid orifice
to deliver an annular curtain of air substantially parallel to the
liquid issuing from said liquid orifice to the mixing chamber;
a liquid impingement member disposed within said mixing chamber and
having a flat circular impingement surface substantially
perpendicular to said liquid orifice to cause liquid issuing
therefrom to spread radially outward and perpendicularly intersect
said annular curtain of air to form an intimate admixture of air
and liquid; and
a discharge orifice disposed through said spray head communicating
said mixing chamber with the atmosphere to discharge said mixture
of air and liquid in said chamber to the atmosphere as a fine
liquid spray.
2. Spraying apparatus for use with a liquid source and a
pressurized air source to produce a fine liquid spray, said
apparatus comprising:
a spray head having an air-liquid mixing chamber therein;
liquid delivery means interconnecting said spray head and said
liquid source;
air delivery means interconnecting said spray head and said air
source;
a liquid passage disposed through said spray head for directing
liquid from said liquid delivery means to said mixing chamber;
an air passage disposed through said spray head for discharging air
from said air delivery means to said mixing chamber;
a control valve disposed in said spray head communicating with said
air and liquid passages, said valve yieldably biased to normally
close said liquid passage and responsive to the pressure of the air
supplied to said air passage to open said liquid passage;
a liquid impingement member disposed within said mixing chamber to
direct liquid delivered through said liquid passage into a
substantially perpendicular intersection with air discharged
through said air passage to form an intimate admixture of air and
liquid; and
a discharge orifice disposed through said spray head communicating
said mixing chamber with the atmosphere to discharge said admixture
of air and liquid in said chamber to the atmosphere as a fine
liquid spray.
3. The spraying apparatus as in claim 2 including an adjustable
liquid flow regulator mounted on said spray head and associated
with said liquid passage to adjustably meter liquid flow
therethrough.
4. Spraying apparatus for use with a liquid source and a
pressurized air source to produce a fine liquid spray, said
apparatus comprising:
a first spray head having an air-liquid mixing chamber therein;
liquid delivery means interconnecting said first spray head and
said liquid source;
air delivery means interconnecting said first spray head and said
air source;
a liquid passage disposed through said first spray head for
directing liquid from said liquid delivery means to said mixing
chamber;
an air passage disposed through said first spray head for
discharging air from said air delivery means to said mixing
chamber;
a liquid impingement member disposed within said mixing chamber of
said first spray head to direct liquid delivered through said
liquid passage into a substantially perpendicular intersection with
air discharged through said air passage to form an intimate
admixture of air and liquid;
a discharge orifice disposed through said first spray head
communicating said mixing chamber with the atmosphere to discharge
said admixture of air and liquid in said chamber to the atmosphere
as a fine liquid spray;
a second spray head having an air-liquid mixing chamber
therein;
a liquid passage disposed through said second spray head for
directing liquid to said mixing chamber;
an air passage disposed through said second spray head for
discharging air to said mixing chamber;
a liquid impingement member disposed within said mixing chamber of
said second spray head to direct liquid delivered through said
liquid passage into a substantially perpendicular intersection with
air discharged through said air passage to form an intimate
admixture of air and liquid;
a discharge orifice disposed through said second spray head
communicating said mixing chamber with the atmosphere to discharge
said admixture of air and liquid in said chamber to the atmosphere
as a fine liquid spray;
air coupling means interconnecting said air passage of said first
spray head with said air passage of said second spray head whereby
air supplied by said air delivery means serially flows through said
first spray head to said second spray head; and
liquid coupling means interconnecting said liquid passage of said
first spray head with said liquid passage of said second spray head
whereby liquid supplied by said liquid delivery means serially
flows through said first spray head to said second spray head.
5. Spraying apparatus for use with a liquid source and a
pressurized air source to produce a fine liquid spray, said
apparatus comprising;
a valve body;
liquid delivery means interconnecting said valve body and said
liquid source;
air delivery means interconnecting said valve body and said air
source;
a spray head connected to said valve body and having an air-liquid
mixing chamber therein;
a liquid passage disposed through said valve body and through said
spray head for delivering liquid from said liquid delivery means to
said mixing chamber;
an air passage disposed through said valve body and through said
spray head for discharging air from said air delivery means to said
mixing chamber;
a discharge orifice disposed through said spray head communicating
said mixing chamber with the atmosphere to discharge air and liquid
within the chamber to the atmosphere;
an air valve mounted on said valve body and associated with said
air passage, said air valve being selectively open and closed to
respectively permit and prevent air flow through said air
passage;
a liquid valve mounted on said valve body and associated with said
liquid passage, said liquid valve being selectively open and closed
to respectively permit and prevent liquid flow through said liquid
passage;
valve activating means mounted on said valve body to open and close
said air and liquid valves in such a manner that said liquid valve
may be opened only if said air valve is first opened and said air
valve is closed only if said liquid valve is first closed;
an adjustable liquid flow regulator mounted on said valve body and
associated with said liquid passage to adjustably meter liquid flow
therethrough;
a stop member disposed on said valve body to engage said liquid
flow regulator and limit the maximum liquid flow through said
liquid passage; and
calibration means associated with said valve body adjacent said
liquid flow regulator to indicate the position of said regulator
and the liquid flow through said liquid passage.
6. Spraying apparatus for use with a liquid source and a
pressurized air source to produce a fine liquid spray, said
apparatus comprising:
a valve body;
liquid delivery means interconnecting said valve body and said
liquid source;
air delivery means interconnecting said valve body and said air
source;
a spray head connected to said valve body and having an air-liquid
mixing chamber therein;
a liquid passage disposed through said valve body and through said
spray head for delivering liquid from said liquid delivery means to
said mixing chamber;
an air passage disposed through said valve body and through said
spray head for discharging air from said air delivery means to said
mixing chamber;
a discharge orifice disposed through said spray head communicating
said mixing chamber with the atmosphere to discharge air and liquid
within said camber to the atmosphere;
an air valve mounted on said valve body and having an air spool
piece disposed within said air passage and yieldably biased to a
closed position in order to block air flow through said air
passage, and partially depressible in order to permit unrestricted
air flow through said air passage, said spool piece including air
flow restriction means to limit air flow through said air passage
when said spool piece is fully depressed;
a liquid valve mounted on said valve body and associated with said
liquid passage, said liquid valve being selectively open and closed
to respectively permit and prevent liquid flow through said liquid
passage; and
valve activating means mounted on said valve body to open and close
said air and liquid valves in such a manner that said liquid valve
may be opened only if said air valve is first opened and said air
valve is closed only if said liquid valve is first closed.
7. Spraying apparatus for use with a liquid source and a
pressurized air source to produce a fine liquid spray, said
apparatus comprising:
a valve body;
a liquid delivery means interconnecting said valve body and said
liquid source;
air delivery means interconnecting said valve body and said air
source;
a spray head connected to said valve body and having an air-liquid
mixing chamber therein;
a liquid passage disposed through said valve body and through said
spray head for delivering liquid from said liquid delivery means to
said mixing chamber;
a first air passage disposed through said valve body and through
said spray head for discharging air from said air delivery means to
said mixing chamber;
a discharge orifice disposed through said spray head communicating
said mixing chamber with the atmosphere to discharge air and liquid
within said chamber to the atmosphere;
a first air valve mounted on said valve body and associated with
said first air passage, said air valve being selectively open and
closed to respectively permit and prevent air flow through said
first air passage;
a liquid valve mounted on said valve body and associated with said
liquid passage, said liquid valve being selectively open and closed
to respectively permit and prevent liquid flow through said liquid
passage;
an air blast orifice associated with said spray head;
a second air passage disposed through said spray head and through
said valve body and communicating with said air blast orifice to
discharge air therefrom supplied by said air delivery means;
a second air valve mounted on said valve body and associated with
said second air passage, said second air valve being selectively
open and closed to respectively permit and prevent air flow through
said second air passage; and
valve activating means mounted on said valve body to open and close
said air valves and said liquid valve in such a manner that said
liquid valve may be opened only if said air valve is first opened,
said first air valve is closed only if said liquid valve if first
closed, said second air valve may be opened only if said liquid
valve is closed, and said second air valve is automatically closed
when said liquid valve is opened.
8. The spraying apparatus as in claim 7 including at least one
pressure relief hole extending from said second air passage to the
atmosphere to prevent air pressure in said second air passage from
exceeding a predetermined level.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates generally to liquid sprayers for producing
an extremely fine spray and finds particular utility in spraying
release agents on dies and in other processes such as, but not
limited to, heating fuel atomization, fuel carburetion, and general
spray painting.
In spraying processes of the types mentioned, it is desirable to
produce liquid droplets as small as possible in order to maximize
the efficiency of the spraying operation. Since a smaller droplet
has a greater area to volume ratio, it can contact the object
surface more intimately and the surface can be properly covered by
using a relatively small total quantity of liquid. It is therefore
important that liquid sprayers be capable of spraying extremely
fine liquid droplets.
As a rule, existing sprayers rely on air turbulence to produce
small liquid particles. The air and liquid are mixed in the spray
head and the turbulent action of the air, along with its expansion
as it exhausts to the atmosphere through the nozzle, is used to
break the liquid up into small droplets to be deposited onto the
object. In order to produce the required degree of air turbulence,
the air must be introduced under very high pressure, which leads to
obvious safety problems. Since the conduits, seals, and valves must
have a high structural strength in order to withstand the high
pressure air, existing sprayers are costly to manufacture, and
those that are hand held are heavy and inconvenient to handle.
Furthermore, if the air is to be maintained in the proper turbulent
condition, the pressure must be consistently held within a
relatively narrow range and pressure regulators are therefore
required. As valves and seals become worn through age and use, the
air pressure becomes difficult to maintain constant and tends to
fluctuate considerably, frequently resulting in a coarse,
non-uniform spray.
The rate of liquid flow in most existing sprayers is set by a
metering screw or similar member that requires tools for
adjustment. The screw is initially set at a position wherein it is
estimated that a desirable mixing ratio of air and liquid will be
obtained. The effect of the spray is then observed, and since the
initial estimate is invariably inaccurate, several trial and error
tool adjustments of the metering screw are necessary before a
proper setting is achieved. In addition, existing sprayers
typically lack a means for duplicating a desirable setting of the
metering screw. A further problem is the tendency of unatomized
liquid to exit from the nozzle of existing sprayers as the air and
liquid are shut off. Thus unatomized liquid is not only wasted, but
it also clogs the nozzle orifices. This leads to a recurring
maintenance problem which is compounded by the difficulty of
dismantling existing sprayers for cleaning and maintenance
purposes.
As previously mentioned, the weight of existing hand held sprayers
makes them difficult and cumbersome for the operator to handle.
Sprayers are usually provided with a standard sized grip or handle
which is fixed in position on the sprayer. Since the normal handle
is not adjustable as to its position on the sprayer, each different
operator cannot achieve a personally comfortable grip on the handle
according to his particular hand size. There is also the problem of
temporarily storing the sprayer between uses. It is typically
placed in a holding bracket or similar structure mounted to a wall
which may be located some distance away from the area of use.
It is not uncommon for various types of debris to be located on the
surface to be sprayed, either in the form of loose particles or
material firmly adhered to the object surface. It is thus necessary
to brush the loose particles from the object or to scrape the
adhered material therefrom. Of course this increases the number of
different implements required (i.e., brush, scraper, air blast,
etc.) and further adds to the inconvenience.
When a pair of separate objects are to be sprayed, such as the
opposite halves of dies used in die casting, it is the normal
practice to utilize either a single spray head which is mounted in
a fixed position to a bracket, or a pair of separately mounted
reciprocating spray heads. The first of these practices is
inefficient because of the time required to successively position
and spray the two halves of the die, whereas the second practice
requires the provision of a pair of additional inlet lines to
supply air and liquid to the second spray head.
Consequently there is a need for a liquid sprayer which overcomes
the aforementioned difficulties associated with existing sprayers.
It is the primary goal of the present invention to meet that
need.
More particularly, an object of this invention is to provide a
sprayer that produces a uniform spray of finely atomized liquid
particles. An important feature in this achievement is the
provision of a novel spray head wherein the air is impacted at a
right angle with the liquid to exert the maximum shearing force
thereon. The resultant air-liquid mixture is caused to undergo
additional expansion as it issues from the nozzle as in atomized
mist.
Another object of the invention is to provide a sprayer of the
character described that operates under low air and liquid
pressure. Due to the novel spray head construction, the air need
not be maintained in a turbulent state, and the air pressure
requirement is therefore reduced considerably (for example to as
low as approximately 30 psi), while the liquid pressure may be as
low as atmospheric pressure in order to permit siphoning.
As a corollary to the preceding object, it is an aim of the
invention to provide a sprayer of the character described in which
air pressure fluctuations have little effect on the operation of
the sprayer. It is a significant feature of the invention that
large fluctuations in the air and liquid pressure have little
effect on the droplet size produced, while relatively large
fluctuations in air pressure cause only insignificantly small
fluctuations in the fluid flow rate.
Still another object of the invention is to provide a sprayer of
the character described wherein the liquid flow rate may be
adjustably metered without the need for tools.
Yet another object of the invention is to provide a sprayer of the
character described in which unatomized liquid is prevented from
leaking through the nozzle.
Another object of the invention is to provide, in a sprayer of the
character described, an improved valve assembly for controlling the
flow of air and liquid to the spray head without requiring special
seals.
A further object of the invention is to provide a hand held sprayer
that is easily and conveniently handled during operation. This
feature is achieved by providing a sprayer that is light in weight
and includes a smoothly contoured handle grip which is adjustable
in position to the comfort of the operator.
A still further object of the invention is to provide a hand held
sprayer of the character described that may be readily stored
temporarily between uses. The provision of an adjustable hanger
allows the sprayer to be hung on a pipe or other structure that is
conveniently located in the spraying area.
Yet another object of the invention is to provide a hand held
sprayer of the character described that is adapted to remove
foreign material from the surface to be sprayed. The inclusion of a
sharp edged scraper on the spray head permits convenient scraping
of packed material from the object surface, while the second
embodiment of the hand held sprayer includes a separate air blast
to blow loose material from the object surface.
Still another object of the invention is to provide a novel spray
head for use in fixed position. The provision of a unique poppet
valve assures proper operation of the block type spray head and
prevent unatomized liquid from clogging the nozzle.
As a corollary to the preceding object, it is among the goals of
the invention to provide a spray head of the character described
that is suitable for attachment to a second spray head such that
the two interconnected heads spray in opposite directions. It is an
important feature of the invention that the two interconnected
spray heads may be supplied with air and liquid from common air and
liquid inlet lines, thereby eliminating the necessity of furnishing
additional supply lines for the second spray head.
Other and further objects of the invention, together with the
features of novelty appurtenant thereto, will appear in the course
of the following description.
DETAILED DESCRIPTION OF THE INVENTION
In the accompanying drawings which form a part of the specification
and are to be read in conjunction therewith and in which like
reference numerals are utilized to indicate like parts in the
various views:
FIG. 1 is a top plan view of a hand held sprayer constructed in
accordance with a preferred embodiment of the invention, with a
portion of the actuating lever broken away to show the air and
liquid valves located therebelow, and with the broken pipe portions
indicating continuous length;
2 is a side elevational view of the device shown in FIG. 1;
FIG. 3 is an enlarged, fragmentary sectional view taken along line
3--3 of FIG. 2 in the direction of the arrows;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3 in the
direction of the arrows;
FIG. 5 is an enlarged sectional side view of the sprayer head taken
along line 5--5 of FIG. 1 in the direction of the arrows;
FIG. 6 is an enlarged plan view of the sprayer head taken along
line 6--6 of FIG. 2 in the direction of the arrows;
FIG. 7 is a fragmentary sectional view of the liquid metering
member threaded into the side of the value housing as shown in FIG.
3;
FIG. 8 is an enlarged sectional view taken through the valve
housing with the valves shown in juxtaposition and the actuating
lever at a position wherein the air valve is partially depressed
and the liquid valve has not yet opened;
FIg. 9 is a fragmentary sectional view taken through the valve
housing (similar to FIG. 3) showing a second embodiment of the hand
held sprayer wherein two air valves and one liquid valve are
employed;
FIG. 10 is a sectional view taken along the line 10--10 of FIG. 9
in the direction of the arrows;
FIG. 11 is a sectional view taken along line 11--11 of FIG. 9 in
the direction of the arrows;
FIG. 12 is an enlarged sectional view taken through the valve
housing of the second embodiment, with the valves shown in
juxtaposition and the actuating lever at a position wherein the air
blast valve is substantially depressed, the air valve is partially
depressed, and the liquid valve has not yet opened;
FIG. 13 is a sectional side view of the sprayer head of the second
embodiment;
FIG. 14 is an enlarged sectional view taken along line 14--14 of
FIG. 13 in the direction of the arrows;
FIG. 15 is a sectional view of a spray head for use in a fixed
position;
FIG. 16 is a sectional view taken along line 16--16 of FIG. 15;
and
FIG. 17 is a side elevational view illustrating two of the spray
heads shown in FIGS. 15 and 16 connected in a stacked
relationship.
Referring now to the drawings in detail, FIGS. 1 through 8
illustrate a first preferred embodiment of the hand held spraying
device 10. An air inlet pipe 11 and a liquid inlet pipt 12 are
connected to flexible hoses (not shown) of conventional air and
liquid sources. The forward ends of pipes 11 and 12 have external
threads for mating connection with a pair of internally threaded
openings 13 and 14 respectively, extending into the rear of a value
housing 15. Slidably mounted on pipes 11 and 12 is a contoured
handle grip 16 which includes two apertures through which pipes 11
and 12 extend. The grip 16 provides a smoothly contoured support
for engagement preferably with the heel or lower palm of the the
operator's hand for comfort and convenience. A set screw 16a within
the handle 16 engages the pipes to fix the handle in a selected
position according to comfort of fit and the size of the operator's
hand.
As best shown in FIG. 3, valve housing 15 is provided with an
internal air passageway 17 extending from the inner end of the
opening 13 to the lower portion of a cylindrical opening 18 which
extends into the valve housing 15 from the top surface thereof. In
a like manner, a liquid passageway 19 extends from opening 14 to a
second cylindrical opening 20 which extends into the valve housing
15 from the top surface thereof at a rearward and sideward location
with respect to opening 18. Threaded into the openings 18 and 20
are an air valve body or gland 22 and a liquid valve gland 23,
respectively. The valve glands 22 and 23 have respective hexagonal
flanged heads 22a and 23a which matingly engage the top surface of
valve housing 15. At their top and bottom portions, valve glands 22
and 23 are of a diameter substantially equal to the diameter of the
respective cylindrical openings 18 and 20 in which they are
contained so that a tight fit is achieved, while each valve gland
is recessed inwardly at an intermediate portion to a diameter less
than that of its containing opening to present a generally annular
space between the recessed portion of the gland and the opening.
With particular reference to FIG. 8, the valve glands 22 and 23 are
each provided with an upper O-ring 25a and 25b respectively, and a
lower O-ring 26a and 26b, respectively, to effect a tight seal
between the valve glands and the respective openings in which they
are contained. The upper O-rings 25a and 25b are fitted in annular
recesses adjacently below the flanged head of each valve gland,
while the lower O-rings 26a and 26b are fitted in similar annular
recesses formed near the bottom of each valve gland. It should be
noted that the depth of the openings 18 and 20 is greater than the
height of the inserted valve glands so that a small air chamber 27
is formed beneath air valve gland 22 and a liquid chamber 28 is
formed beneath liquid valve gland 23.
Air valve gland 22 has a central bore 30 therein which diverges
outwardly in conical fashion at its extreme lower portion. A valve
element comprising an air valve spool 31 is slidably received in
bore 30. Air valve spool 31 includes a head portion 31a, a stem
portion 31b of reduced diameter, and a tapered portion 31c. It is
to be noted that head portion 31a terminates in a square shoulder
31d. Spaced below tapered portion 31c is a collar 31e of a diameter
slightly larger than that of bore 30. Carried intermediately within
a grooved recess on head portion 31a is a tightly fitting O-ring
32a, while another O-ring 33a is carried in the similar groove
formed between tapered portion 31a and collar 31e. A spring 34a is
biased against the underside of collar 31a and seats within a
recess 35a located at the bottom of cylindrical opening 18. The
spring 34a continually biases air valve spool 31 to its uppermost
position whereby the central bore 30 is effectively sealed from air
chamber 27 by O-ring 33a seating against the flared lower edge of
the gland 22.
In a similar manner, a liquid valve spool 36 is slidably mounted in
a bore 37 extending centrally through liquid valve gland 23 and
includes a head portion 36a, a stem 36b of reduced diameter, a
tapered portion 36c, and a collar 36e. Liquid valve spool 36
differs from air valve spool 31 only in that its head portion 36a
has a tapered shoulder 36d in contrast to the square shoulder 31d.
Carried intermittently within a grooved recess on head portion 36a
is a tightly fitting O-ring 32b, while the groove between tapered
portion 36c and collar 36e carries another O-ring 33b. A spring 34b
is biased against the underside of tapered portion 36c seats within
a recess 36b located at the bottom of cylindrical opening 20. The
spring 34b continually biases liquid valve spool 36 to its
uppermost position whereby the central bore 37 is effectively
sealed from liquid chamber 28 by O-ring 33b seating against the
flared lower edge of the gland 23 in the position as shown in FIG.
8.
A plurality of small apertures 40 extend laterally through the
recessed intermediate portion of air valve gland 22, providing
communication between the portion of bore 30 surrounding the air
valve stem 31b and an air exit passage 41 which extends generally
forwardly within valve housing 15. Similarly, liquid valve gland 23
is provided with a plurality of apertures 42 through its recessed
intermediate portion. Apertures 42 connect bore 37 with a liquid
passage 43 which extends forwardly within valve housing 15. As
FIGS. 3, 4 and 7 most clearly show, liquid passage 43 has a
90.degree. turn therein and terminates at the inward portion of a
cylindrical metering hole 47 which extends into one side of valve
housing 15. A liquid exit passage 48 extends inwardly from metering
hole 47 and turns 90.degree. to extend forwardly within the valve
housing.
With reference now particularly to FIG. 7, the cylindrical hole 47
is threaded in order to receive a metering member 50, the knob
portion 50a of which protrudes from hole 47. The inward portion of
member 50 is grooved to carry an O-ring 51 which provides a tight
seal against the walls of metering hole 47. A needle valve 52 is
threaded into a bore 53 located centrally within metering member 50
and protrudes beyond the inward end of member 50. The threaded
relationship between needle valve 52 and member 50 permits
adjustment of the valve position with respect to the metering
member. The tip of needle valve 52 may be extended wholly or
partially into liquid exit passage 48 as metering member 50 is
threaded inwardly by rotation of its protruding knob portion
50a.
The surface of the valve housing surrounding the knob 50a may be
provided with calibration marks (not shown) to assist in
duplicating a desired setting of the metering member 50. For
alignment with the calibration marks, a pointer 54 is carried in a
transverse opening in knob 50a and protrudes sidewardly therefrom.
A boss 55 (FIG. 2) projecting from the surface of the valve housing
serves to limit the outward position of needle valve 52 by
engagement with pointer 54 as the limiting position is reached.
Boss 55 and pointer 54 thereby provide a maximum rate of fluid flow
from passage 43 into passage 48.
To manipulate the valves, a plate-like hand lever 58 of a size
slightly greater than the valve housing is pivotally mounted to a
projection 59 extending upwardly from the top forward portion of
valve housing 15. A pivot shaft 60 extends through projection 59
and through a pair of spaced forks 58a and 58b of the lever between
which is received the projection 59. Upward pivoting of lever 58 is
limited by engagement between its front surface 58c and the upper
edge 59a of projection 59, while lever 58 may be pivoted downwardly
to contact and depress the two valve spools 31 and 36.
As shown in FIG. 3, a sleeve 62 is threaded into a cylindrical
opening 63 which is recessed into the front surface of valve
housing 15. The respective air and liquid passages 41 and 48
terminate at opening 63. Sleeve 62 contains the rearward end of an
elongate pipe 64, the hollow interior of which thereby communicates
with the air exit passage 41. A small diameter conduit or tube 65
extends centrally within elongate pipe 64 throughout the length
thereof, and the rearward end of tube 65 extends tightly into
liquid exit passage 48. The pipe 64 and tube 65 extend from the
valve housing 15 to the spray head to be described.
FIGS. 1 and 2 illustrate a slidable hanger 66 having a hook-like
tip 66a. Hanger 66 is slidably mounted on pipe 64 by means of a
bore through its body portion, and the hanger may be fixed in a
desired position on pipe 64 by a set screw 66b.
Threaded onto the forward end of pipe 64 is a sprayer head 70.
Referring now to FIG. 5 which shows the interior of sprayer head 70
in cross section, the forward end of tube 65 fits tightly into an
L-shaped liquid passageway 71, and the hollow interior of pipe 64
communicates with a short angled air passageway 72. Liquid
passageway 71 passes centrally through a cylindrical boss 73 and
terminates at an annular mixing chamber 74. A cylindrical spray tip
75 formed as part of a nozzle 80 is disposed centrally in mixing
chamber 74 with its circular inward surface 75a spaced immediately
ahead of and perpendicular to liquid passageway 71. An annular
chamber 76 surrounds boss 73 and communicates with the end of air
passageway 72. A washer 77 having a bore slightly larger than boss
73 surrounds the end of the boss to substantially separate annular
chamber 76 from mixing chamber 74, the two chambers being connected
only by a small annular slot 78 formed as a result of the clearance
between boss 73 and washer 77.
Nozzle 80 has a plurality of orifices 81 therein which provide
access from mixing chamber 74 to the outside atmosphere. A
retaining nut 82 having a central bore is threaded into an opening
in the face of sprayer head 70. The body of nozzle 80 extends
through the bore in nut 82, while the nut engages an enlarged
flange 80a formed on the inward end of nozzle 80 to retain the
nozzle and the washer 77 located therebehind in position within
head 70. Finally, a scraper 83 having a sharp edge 83a suitable for
scraping purposes is secured to the top of sprayer head 70 by a
pair of screws 84.
In operation, respective sources of pressurized air and pressurized
or atmospheric liquid are connected to air and liquid inlet pipes
11 and 12, and handle 16 is secured in a convenient position near
valve housing 15. Knob 50a is rotated to an appropriate position
wherein needle valve 52 permits the desired liquid flow rate. The
threads of metering member 50 and the tight fit of O-ring 51 in
hole 47 firmly hold member 50 in its set position, while the
setting may be varied if desired by rotating knob 50a. As hand
lever 58 is pivoted downwardly to overcome the upward biasing force
of springs 34a and 34b and depress valve spools 31 and 36, the
staggered locations of the valves causes air valve spool 31 to be
contacted and depressed by the lever before liquid valve spool 36
is engaged thereby. At this point, the valves are in the position
illustrated in FIG. 8, with air valve spool 31 slightly depressed
and lever 58 just moving into engagement with liquid valve spool
36. The depression of air valve spool 31 has caused its lower
O-ring 33a to move downwardly against the force of spring 34a from
its sealing position in abutment with the flared lower edge of air
valve gland 22. Consequently, the air that has been introduced into
air chamber 27 through pipe 11 and passage 71 is permitted to flow
from the air chamber upwardly into bore 30, exiting from the bore
into air exit passage 41 through apertures 40 and the annular space
surrounding the recessed intermediate portion of valve gland 22.
The precedes then passes to sprayer head 70 through elongate pipe
64 and exhausts to the atmosphere through nozzle 80 in a high
velocity jet produced by passage through the restricted slot 78. It
is noted that at this point the bottom O-ring 33b of liquid valve
spool 36 is seated in abutment with the flared lower edge of liquid
valve gland 23 providing an effective seal between liquid chamber
28 and bore 37 so that liquid is prevented from flowing to the
sprayer head. Thus as the sprayer is operated, a blast of air alone
from the nozzle preceds the beginning of the liquid spraying.
As lever 58 is pivoted downwardly an additional distance, liquid
valve spool 36 is depressed and its lower O-ring 33b moves
downwardly from its sealing position. The liquid that has been
introduced into liquid chamber 28 through pipe 12 and liquid
passage 19 is then permitted to flow into bore 37. From bore 37 the
liquid flows through apertures 42 into the recessed area around
gland 23, through liquid passage 43, and past needle valve 52 at a
predetermined rate set by the position of metering member 50. The
liquid then continues into liquid exit passage 48 and through the
small tube 65 to the sprayer head. It is to be noted that
simultaneously with the opening of the liquid valve by the
additional downward pivoting of lever 58, the square shoulder
portion 31d of air valve spool 31 is pushed downwardly the position
shown by broken line of FIG. 8, and thus restricts somewhat the air
flow from bore 30 to the apertures 40, providing only the amount of
air necessary for spraying purposes. Since it is desirable for a
relatively high flow rate of air for the air blast alone, shoulder
31d does not interfere with the flow of air into apertures 40
unless the liquid valve is in the open position.
When the spraying begins as both valve spools 31 and 36 are
depressed, the interaction between the air and liquid thereby
entering sprayer head 70 is best understood with reference to FIG.
5. The liquid from the small tube 65 enters liquid passageway, from
where it perpendicularly impinges on the circular flat surface 75a.
This perpendicular collision with the spray tip reflects the liquid
radially outwardly from surface 75a in a thin sheet.
Simultaneously, the air flowing from air passageway 72 into the
annular chamber 76 is forced through the reduced area clearance
slot 78, the restriction in area producing a corresponding increase
in the velocity of the air. As the high velocity air enters mixing
chamber 74 from slot 78, a first expansion occurs since the
pressure in the mixing chamber is considerably less than that in
the annular chamber 76. The high speed, expanding air from slot 78
is directly circumferentially past circular surface 75a at a right
angle with respect to the surface 75a, thereby colliding at a right
angle with the thin sheet of liquid radiating outwardly from
surface 75a. The shearing force exerted on the liquid is maximum
because of the right angle collision, and this powerful shearing
force, along with the expansion of air, divides the liquid into
extremely small particles containing a quantity of air. As these
small particles exhaust to the atmosphere through nozzle 80 a
further expansion due to the relatively low atmospheric pressure
completes the atomization process and breaks the liquid particles
up into even smaller particles which spray from the nozzle in a
finely atomized mist. The right angle collision between the air and
liquid occurs at the point of lowest pressure in the air stream,
allowing liquid to be siphoned if desired.
When lever 58 is released to discontinue spraying, the action of
springs 34a and 34b force the respective air and liquid valve
spools 31 and 36 upwardly to their sealing positions wherein bores
30 and 37 are again sealed against flow. Due to the location of
liquid valve spool 36 farther from the pivot axis of lever 58 than
air valve spool 31, O-ring 33b moves into abutment with the flared
lower edge of liquid valve gland 23 to cut off the liquid flow
before the O-ring 33a on the air valve spool moves upwardly to its
sealing position against the flared lower edge of air valve gland
22 to cut off the air flow. The liquid flow is thus always cut off
prior to the air flow, and any liquid remaining in sprayer head 70
after the liquid flow is stopped is acted on by a short blast of
air before the air flow stops. In this manner, unatomized liquid is
precluded from dripping through nozzle 80 and clogging the orifices
thereof.
Referring now to FIGS. 9 through 14, a second embodiment of the
hand held spraying device is generally designated by numeral 10'.
The sprayer 10' is similar in construction to the first embodiment,
with the main modification being that sprayer 10' includes a second
air path to produce a separate blast of air and an additional valve
to regulate the airflow therethrough. Like part in the first and
second embodiments are designated by the same numerals with primes
added thereto in FIGS. 9-14, and the primed numerals indicate parts
corresponding to those previously described in the first
embodiment, except for certain changes that are hereinafter set
forth.
With initial reference to FIGS. 9 and 10, the rearward top portion
of valve housing 15' (which may be enlarged to accommodate the
added valve) includes a boss 15a' located rearwardly on the valve
housing relative to openings 18' and 20'. A threaded opening 21'
extends downwardly into boss 15a' with its bottom portion connected
to an intermediate portion of the air passageway 17'. It is noted
that air passageway 17' provides an air inlet to both openings 18'
and 21'. An air blast valve gland 24' with a bore 38' having an
enlarged lower portion is threaded into opening 21'. Valve gland
24' includes a hexagonal flanged head 24a' and has top and bottom
portions substantially equal in diameter to opening 21', while an
intermediate portion of valve gland 24' is recessed to a lesser
diameter than that of opening 21'. For sealing purposes, an upper
O-ring 25c' is fitted in a groove in the upper portion of valve
gland 24', and a lower O-ring 26c' is fitted in a similar groove in
the lower portion of valve gland 24'. Since valve gland 24' is
shorter than the depth of opening 21', an air chamber 29' is formed
beneath the gland.
Slidable within the central bore 38' in valve gland 24' is an air
blast valve spool 39' having a head 39a', a stem 39b' of reduced
diameter, a tapered portion 39c', and a collar 39e'. It is to be
noted that in the second embodiment all three valve spools 31', 36'
and 39' include a tapered shoulder 31d', 36d', and 39d',
respectively, on the underside of their heads. It is further
pointed out that air blast valve spool 39' is of slightly greater
height than the other two spools 31' and 36' and carries a pair of
O-rings 32c' and 32d' in respective grooves in its head, as well as
the O-ring 33c' between tapered portion 39c' and collar 39e'. Like
the other two valve elements, air blast valve spool 39' has a
spring 34c' biased against the underside of its collar 39e' and
seating in a recess 35c' located at the bottom of opening 21'.
Spring 34c' continuously biases air blast valve spool 39' to its
uppermost position whereby bore 38' is sealed from air chamber 29'
by O-ring 33c' seating against the flared lower edge of gland 24'.
The recessed intermediate portion of air blast valve gland 24'
includes a plurality of apertures 44' connecting bore 38' with the
generally annular space surrounding the recessed gland portion and
an air blast exit passage 45'. As in the first embodiment, liquid
exit passage 48' connects to the hollow interior of the small
elongate tube 65'. However, in the second embodiment, unlike the
first embodiment, tube 65' is surrounded by a larger diameter tube
61'. As FIGS. 9 and 10 illustrate, air exit passage 41' connects
with the hollow interior of tube 61', while the forwardly extending
air blast passage 45' connects with the interior of the elongate
pipe 64' which is threaded into a cylindrical opening 63' in the
front surface of valve housing 15' and which surrounds tubes 61'
and 65'.
FIG. 13 shows the connection of pipe 64' and tubes 61' and 65' with
the sprayer head 70'. Sprayer head 70' has the same internal
structure as described for the head 70 of the first embodiment to
direct air and liquid into a right angle collision within the
sprayer head. However, sprayer head 70' includes an additional
passageway 79' to provide a separate path for the air flowing
through the large pipe 64'. Liquid from the innermost tube 65'
enters liquid passageway 71', from where it is directed into a
collision with the air which enters air passageway 72' from tube
61' by means of the previously described internal structure of the
sprayer head. Connected with the hollow interior of pipe 64' is the
air blast passageway 79' which has a right angle turn therein. A
second and smaller nozzle 84' which exhausts to the atmosphere is
threaded into head 70' forwardly of nozzle 80'. Nozzle 84' connects
to air blast passageway 79' and includes a plurality of pressure
relief holes 85' extending through the side thereof at an upward
angle to prevent the pressure buildup from exceeding a safe
level.
The operation of the second embodiment is similar to that of the
first, except that a separate blast of air from nozzle 84' precedes
the spraying in order to blow loose particles from the surface of
the object to be sprayed. With particular reference to FIG. 11 it
is apparent that due to its elevated position, air blast valve
spool 39' is the first valve to be contacted and depressed by lever
58. The depression of valve spool 39' permits the air that enters
chamber 29' from passage 17' to pass into bore 38', and from there
through apertures 44', passage 45', and pipe 64' to sprayer head
70' for exhaust through nozzle 84'. As lever 58' is pivoted further
downwardly, air valve spool 31' is next depressed because of its
position nearer the pivot axis than the liquid valve spool 36'.
The position shown by FIG. 12 is one wherein air blast valve spool
39' is depressed almost totally, air valve spool 31' is depressed
only partially, and liquid valve spool 36' has not yet been
depressed. It is to be noted that additional downward pivoting of
lever 58' from the FIG. 12 position not only opens liquid valve
spool 36' to permit the flow of liquid, but also depresses the
O-ring 32c' carried on the head portion of air blast valve spool
39' to a position below apertures 44'. This action of O-ring 32c'
effectively seals apertures 44' from chamber 29' and thereby cuts
off the air blast from nozzle 84'. The elevated position of air
blast spool 39' causes lever 58' to depress it to a greater depth
within its bore as compared to maximum depression of the other two
valve spools. The additional downward travel of air blast valve
spool 39' as lever 58' is pivoted into contact with liquid valve
spool 36' results in the separate air blast from nozzle 84' being
cut off by O-ring 32c' as the spraying of liquid from nozzle 80'
begins.
The spraying of the air-liquid mixture from nozzle 80' begins as
previously related when lever 58' is pivoted downwardly past the
FIG. 12 position to open liquid valve 36'. In the manner described
in connection with the first embodiment, a finely atomized mist
sprays from nozzle 80' as a result of the right angle collision of
the air and liquid in conjunction with the double expansion
produced by sprayer head 70'.
Turning now to FIGS. 15 through 17, an embodiment of a spray head
for use in a fixed position is generally designated by the numeral
10". Although this embodiment produces a right angle collision
between the air and liquid in a similar manner as the other two
embodiments, the entirety of sprayer 10" comprises a block type
sprayer head 70" which is mounted in a fixed position to a wall or
ceiling or to a bracket which is positionally adjustable. The spray
head 70" is so constructed as to be stackable upon a second
identical head such that the respective nozzles point in opposite
directions, an arrangement suitable for simultaneously spraying
opposite halves of a die or other object having two separate,
opposing parts.
The top surface of head 70" has a pair of cylindrical threaded
openings 88" and 89" extending therein which are adapted for
connection to respective air and liquid supply lines 90" and 91".
It is preferred that this connection be sufficiently rigid as to
serve as the sole means for mounting the spray head. Accordingly,
the openings 88" and 89" preferably receive respective quick
disconnect couplings 88a" and 89a" which rigidly connect hoses 90"
and 91" to head 70". A threaded recess 92" is provided in a side of
head 70" to serve as an additional mounting means.
Referring particularly to FIG. 15, opening 88" terminates at a
small air passage 93", while opening 89" connects at its end with a
liquid passage 94". Passages 93" and 94" extend downwardly in
spaced relation to pass from spray head 70" through the bottom
surface thereof. At their bottom portions, passages 93" and 94" are
enlarged somewhat and are threaded to receive set screws (not
shown).
A metering member 50" having a hexagonal flanged head 50a" is
threaded into an opening 47" formed in the side of head 70"
opposite the threaded recess 92". Metering member 50" has a needle
valve 52" threaded in its central bore and projecting inwardly
therefrom to extend transversely through a portion of liquid
passage 94". Needle valve 52" also projects into another liquid
passage 95" which connects at a right angle with an intermediate
portion of passage 94" and extends inwardly therefrom. The inward
portion of metering member 50" is grooved to carry an O-ring 51"
which provides a tight seal against the walls of opening 47". A
vertical pin 96" (FIG. 16) located in a groove at the side of
opening 47" engages the opposite ends of an annular groove 50b"
formed intermediately on member 50" to limit the distance member
50" may travel with respect to opening 47". Metering member 50"
preferably includes a pointer member or the like that extends from
head 50a" and aligns with calibration marks (not shown) on the
surrounding surface of the spray head to permit duplication of
settings of member 50".
Intermediately along air passage 93", a passage 97" connects
thereto at a right angle. Passage 97" in turn connects at one end
to an annular chamber 76" and at its other end to a bifurcated bore
98" formed in the side of head 70". Bore 98" has an outer portion
98a" of larger diameter than its inward portion 98b", which
connects to the liquid passage 95" at its extreme end.
A poppet valve 99" having an enlarged head and a reduced diameter
stem is slidably disposed in bore 98" with its head located in
enlarged bore portion 98a" and its stem in the smaller bore portion
98b". The head of poppet valve 99" comprises a pair of spaced
flanges 99a" and 99b" of a diameter substantially equal to that of
bore portion 98a". A groove formed between flanges 99a" and 99b"
carries an O-ring 100" which provides a seal against the walls of
bore portion 98a". The stem of poppet valve 99" extends centrally
from the flat surface of flange 99b" and carries an O-ring 101" in
a groove formed between its top portion 99c" and an intermediate
collar 99d". Portion 99c" and collar 99d" have diameters equal to
the bore portion 98b", while collar 99d" is tapered downwardly. The
stem terminates in a frusto-conical tip 99e" and carries a small
O-ring 102" in a groove formed between tip 99e" and collar 99d".
The inward movement of poppet valve 99" is limited by engagement of
flange 99b" with the shoulder formed between the bore portions 98a"
and 98b".
A spring 103" is utilized to continually bias poppet valve 99"
inwardly toward a position wherein the small O-ring 102" is seated
on a flared shoulder 71a" which forms the entrance to a liquid
passageway 71" having an enlarged inward portion which tapers to a
smaller outward portion. One end of spring 103" is fitted in a
short central recess 104" in the outward face of the poppet valve
head while the opposite end of the spring seats in a recess 105"
formed centrally in a retaining member 106". The retainer 106" is
secured by a snap ring 106a" or the like received in a groove
formed in the side walls of bore 98" in order to retain poppet
valve 99" in the bore. It is noted that there is a clearance
between valve 99" and retainer 106" so that the valve may be moved
outwardly a short distance in response to pressure upon the inward
surface of flange 99b".
Liquid passageway 71" extends centrally through a cylindrical boss
73" which is turn extends centrally through the annular chamber
76". A washer 77" having a bore slightly larger than boss 73" is
positioned around the end of boss 73" to present a small annular
slot 78" between the boss and washer. Washer 77" is retained in
position by a nozzle 80" which is threaded into an opening in the
face of head 70" opposite bore 98". The inward portion of nozzle
80" includes a cylindrical spray tip 75" having a flat, circular
inward surface 75a". Surface 75a" is spaced immediately ahead of
the end of liquid passageway 71" and is oriented perpendicular
thereto. An annular mixing chamber 74" formed around spray tip 75"
communicates with chamber 76" through the small slot 78". A
plurality of orifices 81" extend through nozzle 80" from mixing
chamber 74" to exhaust to the atmosphere.
Opposite corners of spray head 70" are bored with bolt holes 108a"
which extend entirely through the head from top to bottom, while a
second pair of bolt holes 108b" which are threaded extend only
partially into the head from the bottom thereof at the other two
corners. By inserting appropriate bolts into the bolt holes of a
pair of identical spray heads 70", the two heads may be stacked
together in an inverted relationship with the respective nozzles
80" spraying in opposite directions as shown in FIG. 17. Since air
and liquid passages 93" and 94" extend entirely through the spray
head, the two heads are stacked with their respective air passages
93" interconnected and their respective liquid passages 94"
interconnected. A pair of O-ring seals 109a" and 109b" (FIG. 15)
which seat in grooves formed around the respective passages 93" and
94" at the extreme ends thereof are utilized to effect a seal
between the connected passages when the two heads are bolted
together. The threaded air and liquid inlet openings 88" and 89" of
the bottom head may be sealed by pipe plugs 110" in combination
with a sealing compound. In this manner a single air source and a
single liquid source supply both of the stacked heads. Of course,
if it is desired to utilize only a single spray head 70" the lower
ends of air passage 93" and liquid passage 94" may be sealed by set
screws and sealing compound (not shown) or by other suitable
means.
To operate the sprayer head 70", the metering member 50" is set to
permit a desirable rate of liquid flow, and the respective air and
liquid sources are turned on. As the air thereby entering air
passageway 97" from passage 93" exerts rearward pressure upon the
surface of flange 98b", O-ring 102" is unseated from shoulder 71a",
and liquid is permitted to flow from passage 94" into passage 95",
through the end of bore portion 98b", and into liquid passageway
71. From passage 71" the liquid perpendicularly impinges on the
circular flat surface 75a" and is reflected radially outwardly
therefrom in a thin sheet. Simultaneously the air flowing from
passage 97" into annular chamber 76" is forced through the small
annular slot 78" and circumferentially past circular surface 75a"
in a direction perpendicular thereto. Passage through the
restricted area slot 78" produces an increase in the velocity of
the air, which also expands as it enters mixing chamber 74" because
of the decreased pressure therein relative to chamber 76". The high
speed, expanding air directed past surface 75a" is caused to
collide at a right angle with the thin sheet of liquid radiating
outwardly from surface 75a", thereby exerting the maximum shearing
force on the liquid. The powerful shearing force, along with the
expansion of the air, divides the liquid into extremely small
particles containing a quantity of air. As these small particles
exhaust to the atmosphere through nozzle 80", a further expansion
due to the relatively low atmospheric pressure completes the
atomization process and breaks the liquid up into even smaller
particles which spray from nozzle 80" in a finely atomized
mist.
It is noted that unless the air source is on, the biasing force of
spring 103" on poppet valve 99" seats O-ring 102" on shoulder 71a"
to seal off the flow of liquid. However, when air pressure is
exerted on flange 99b", poppet valve 99" is forced outwardly to
unseat O-ring 102" from shoulder 71a" and permit liquid to flow
through spray head 70". In this manner, the action of poppet valve
99" permits liquid flow only if there is also air flow and thereby
prevents unatomized liquid from dripping through nozzle 80".
From the foregoing it will be seen that this invention is one well
adapted to attain all the ends and objects hereinabove set forth
together with other advantages which are obvious and which are
inherent to the structure.
It will be understood that certain features and subcombinations are
of utility and may be employed without reference to other features
and subcombinations. This is comtemplated by and is within the
scope of the claims.
Since many possible embodiments may be made of the invention
without departing from the scope thereof, it is to be understood
that all matter herein set forth or shown in the accompanying
drawings is to be interpreted as illustrative and not in a limiting
sense.
* * * * *