JPH1080653A - Spray nozzle and method for atomizing and spraying fluid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the complete and uniform mixing of air and fluid material and to perfectly atomize the fluid material in uniform density by supplying compressed air into an air and fluid mixing chamber through a plurality of air ports inclined forward and regularly spaced in the peripheral wall of the mixing chamber in the circumferential direction. SOLUTION: A fluid material having a high content of granular component is atomized by a spray gun 10. Namely, the fluid material under pressure is mixed with pressurized air, the liq. in the atomization material is atomized before the mixture is discharged, and an atomizer valve interlocked with an air valve is provided. The atomizer valve is formed by inserting a valve element freely movable back and forth into the valve chest 40 having an inlet for pressurized air, an inlet 45 for the material and an outlet for the mixture, and the pressurized air is supplied into the valve chest 40 through the air inlet. The atomization material from the inlet 45 are mixed with the pressurized air, the mixture flows into a nozzle 90a, and the mixing is promoted in tis case by the pressurized air passed through the air ports 126a from an air plenum 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray nozzle for spraying a flowable material, and more particularly to an internally mixed air spray nozzle.

[0002]

BACKGROUND OF THE INVENTION There are various types of known fluid material spray devices, commonly referred to as "spray guns". One type of such device is an air spray gun, in which fluid material is atomized by interaction with compressed air into a spray. There are two main types of this air spray gun. An external mixing type in which the compressed air interacts with the fluid material outside the spray gun, for example in front of the spray nozzle of the gun; and Internal mixing type that interacts with the material.

[0003] Internally mixed air spray nozzles are heavily filled from low viscosity paints and colorants.
Well suited for spraying fluid materials over a wide range of viscosities, up to high viscosity materials, but especially difficult to spray materials having a high particle content.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a material having a high viscosity and / or a high concentration of fiber and / or abrasive particles, in particular an external thermal finishing device.
rior insulation finish sy
), which has been developed in combination with the development of a spray gun for spraying particle-loaded mortars, such as plaster or regular stucco, or synthetic stucco, used in EIFS. , But with broader applications.

[0005] These devices and the attendant difficulties are described in detail in the above-mentioned previously filed application.

[0006] Basically, it is an object of the present invention to provide an easy-to-use internally mixed air atomizing nozzle which, for example, provides a durable and attractive external finish to buildings. Therefore, a spray of a flowable material having a uniform spray density is discharged from a nozzle for spraying on an external surface of a building, thereby performing a more efficient operation.

The present invention is directed to a flowable material of all viscosities,
A new and improved internally mixed air atomizing nozzle is provided, especially for atomizing high-viscosity materials such as stucco filled in large quantities.

[0008]

The main features of the present invention are as follows.
Unlike conventional designs, there is no back pressure in the nozzle and the flowable material, especially heavy, is filled (heavy lad).
en) lies in the development of internal mixing nozzles that generate a vacuum or suction to assist in the supply of material through the nozzles.

Another feature is that compressed air is directly introduced into the air and fluid mixing chamber through a plurality of forward-facing circumferentially spaced ports on the peripheral wall of the mixing chamber.
Feed more or less tangentially along the circumference to help generate material supply or suction forces, to ensure complete and uniform mixing of air and fluid material, and to achieve uniform spray density of fluid material. The aim is to ensure that a complete spray is emitted from the nozzle.

Another aspect of the present invention is to establish a special relationship between the air port area and the working pressure of air and fluid to ensure that the above objects and advantages are achieved. .

Another feature of the present invention resides in the development of a unitary integral internal mixed air atomizing nozzle that combines the conventional three-element assembly into an integral product.

Another object of the present invention is to provide an improved internally mixed air atomizing nozzle that is very economical to manufacture and allows for large tolerances in the manufacturing process.

[0013] These and other objects, features, and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a detailed description of embodiments of the present invention which the present inventor considers to be the best mode for practicing the present invention.

Referring to the accompanying drawings, and in particular to FIG. 1, a spray gun 10 for spraying a flowable material containing a high concentration of particulate components.
Is shown. The spray gun 10 comprises a barrel 12, a handle 1
4, including a fluid material valve 31, an air valve 70, and two inlets 27 and 45. 27 is for pressurized air and 45 is for the flowable material to be sprayed. The spray gun shown here is disclosed in U.S. patent application Ser. No. 08 / 407,320 (1).
(Submitted March 20, 995).

The spray gun mixes a flowable material at a first pressure with air pressurized to a second pressure (preferably higher than the first pressure) and before the mixture is released. It operates to atomize the liquid in the spray material. The spray valve 31 provided on the barrel 12 controls the flow of the fluid material. An air valve 70 provided on the handle 14 controls the flow of pressurized air.

The spray valve 31 cooperates with the air valve 70 such that when the air valve is in the open position, the spray valve is also in the open position, and when the air valve is in the closed position, the spray valve is also in the closed position. .

The flowable spray material is generally from about 1.7 to 3.4.
atm (25-50 psi) pressure and spray valve 31
Is opened, the spray material flows from the spray material inlet 45 into the valve chamber 40, where the spray material is mixed with the first supply pressurized air. Next, the spray material is spray nozzle 5
The second feed pressurized air is added to the nozzle, the liquid in the spray material is atomized, and the mixture is discharged from the spray gun 10.

The spray valve 31 comprises a valve chamber 40 and a valve element 32. The valve chamber has an inner wall, preferably the inner wall is shaped to define a long cylindrical lumen.

The valve chamber has an inlet for pressurized air, an inlet for spray material, and an outlet for mixture. The air inlet is a spray valve passage 80, which communicates with the rear end of the valve chamber so that pressurized air can flow into the valve chamber 40. Pressurized air flows from the spray valve passage 80 through the conduit 33 in the valve element 32 to the front of the valve chamber. The spray material inlet 45 communicates with an intermediate portion of the valve chamber so that the spray material can flow into the valve chamber. The atomized material mixes with the pressurized air and flows from the valve chamber through the outlet 46 into the nozzle 50.

The valve element 32 is slidably displaceable within the valve chamber 40 between an open position and a closed position. In this embodiment, the valve element 32 comprises the front cylindrical body part 3
6 and a valve stem 38 projecting from the rear, the valve stem 38 preferably having a smaller diameter than the valve body.

As described above, the conduit 33 passes through the valve element 32, and pressurized air can flow from the spray valve passage 80 into the valve chamber front through the valve element. Preferably, the front of the conduit 33 is coaxial with the valve body 36 and opens into the front of the valve element. The rear part of the conduit is preferably bent towards the outer end of the valve element, the latter opening at the rear part of the valve body 36 into the annular space surrounding the valve element in the valve chamber 40. .

For proper operation, the gap between the outer diameter of the valve body 36 and the valve chamber lumen must be between two limits. The sliding gap must be greater than zero so that the valve element can slide in the valve chamber. That is, the diameter of the valve body must be smaller than the valve chamber lumen.

The upper limit of the sliding gap is determined by the size of the particles in the spray material. The sliding gap should be less than or equal to the size of the average particles in the spray material, and the particles will
Do not pass through the sliding gap between

Particles that cannot pass through the sliding gap are sprayed by the spray valve 3
When 1 is closed, it agglomerates around the spray material inlet 45. The aggregation of the particles forms a seal and prevents the liquid in the spray material from leaking from the sliding gap into the valve chamber 40 when the spray valve 31 is closed. Such a seal allows the nozzle 50 to be removed and cleaned or replaced with little or no leakage when the sprayed material is under pressure.

When using spray materials which do not contain too much content, the sliding gap should be small. Preferably, the sliding gap is made of an elastomeric paint (usually 3 to
(Having a viscosity of 6 poise) or higher. Spray material is about 6.8atm
When under a pressure of (100 psi), the maximum sliding clearance that prevents leakage is 0.175 mm (0.0075 inch). Preferably, this sliding gap is about 0.019 mm
(0.00075 inch).

By reducing the sliding gap to this limit, the nozzle can be removed without leakage, even when using spray material which does not contain a large amount of particulate components. If the sliding gap is not reduced, it may be necessary to use a resilient seal between the valve body and the valve chamber to prevent the leakage of spray material that does not contain a large amount of particulate components.

When the spray valve 31 is in the open position, the valve element 32 allows the spray material to flow through the spray material inlet 45. To stop the flow of the spray material, the valve element is slid over the spray material inlet. Preferably, the valve element slides longitudinally from an open position at the rear of the valve chamber 40 to a closed position at the front of the valve chamber.

The valve body 36 is long enough to ensure that the entire spray material inlet 45 is covered when the valve element 32 is in the closed position. The nozzle 50 also acts as a stop to prevent the valve body 36 from displacing beyond the spray material inlet 45, thereby completely covering the spray material inlet when the valve element is in the closed position. Ensure that By completely covering the spray material inlet, the valve body prevents the spray material from flowing into the valve chamber 40 and more specifically into the rear of the valve chamber. This inflow would hinder the rearward displacement of the valve element. To be of sufficient length, the length of the valve element 32 must be greater than the diameter of the spray material inlet 45.

The spray material contains particles that can stay between the valve body 36 and the valve chamber wall in front of the spray material inlet 45. These stagnant particles can prevent the valve element 32 from closing properly, so that spray material can leak through the valve element when the valve element is displaced toward the closed position.

To prevent the accumulation of accumulated particles, the valve body 36
And the spray material inlet 45 have cooperating sharp edges. The front of the valve body 36 is preferably flat and has a sharp lip on its outer peripheral surface. The spray material inlet 45 has a sharp contour on the wall of the valve chamber 40.

Between the sharp edge of the valve body and the well-defined contour of the inlet, there is provided a shearing clearance smaller than the average diameter of the particles in the spray material. Thus, as the valve body 36 flicks across the spray material inlet 45, the sharp lip cooperates with the sharp contour to provide a shearing action. This shearing action removes any particulate matter that can accumulate and prevent proper closing of the spray valve 31. In this embodiment, the shear gap is the same as the sliding gap described above.

As described above, the spray valve 31 is connected to the handle 14.
Cooperates with an air valve 70 provided in the Trigger mechanism 71
Activates the air valve 70 and when the trigger is pressed, the air valve is opened. The air valve allows pressurized air to enter spray gun 10 through air supply inlet 27 when opened. When the trigger 71 is released, the air valve 70 closes and the air supply is cut off.

When the air valve is opened, air flows into the lower air passage 73 of the spray gun handle 14. From there, air flows into the upper air passage 74 of the barrel 12 of the spray gun. Due to the pressure of the supply air, the piston 85 is displaced in the rear air chamber 76 and the remaining supply air flows toward the nozzle 50 through the upper air passage.

The piston 85 cooperates with the valve stem 38 to open the spray valve when the piston is displaced by air pressure. In this embodiment, nut 86 secures the piston to valve stem 38. The position of the nut 86 on the valve stem 38 with respect to the piston 85 can be adjusted, and thus the open position of the valve element 32 can be adjusted.

Behind the piston 85, a spring 87 pushes the valve stem 38 forward, and when the air valve 70 is closed, the valve element 32 is moved toward the closed position. The air pressure on piston 85 must be sufficient to overcome the biasing force of spring 87 and move valve element 32 to the open position.

The supply air flowing toward nozzle 50 through upper air passage 74 is split into two streams. One stream flows into the spray valve passage 80 connecting the upper air passage 74 to the rear of the spray valve chamber 40. The second flow is
An air chamber surrounding the nozzle 50 with the upper air passage (air)
plenum) or an air galler
y) Air plenum connecting to 60
(passage) 78.

The air flowing through the spray valve passage 80 is supplied to the valve chamber 4
0, and then through the conduit 33 of the valve body 36 to the front of the valve chamber. Air flowing through the valve body 36 is combined with the spray material and moves the spray material toward the nozzle 50.

The spray material has a tapered port 5 inside.
2 and into the nozzle. The spray material flows into the mixing chamber 54 through the nozzle port. In the mixing chamber, the sprayed material is returned to the nozzle passage 53 exiting from the charging chamber 60.
Combined with pressurized air flowing through. This pressurized air atomizes the liquid in the spray material, after which the mixture is discharged through outlet 56.

As described above, the pressurized air not only atomizes the liquid in the spray material but also displaces the piston 85. The air pressure required for the displacement of the air piston is generally greater than the air pressure required to atomize the spray material liquid and produce the desired spray pattern. Therefore, preferably, a normal throttle valve (not shown) is arranged in the upper air passage 78 to variably control the air pressure flowing through the nozzle.

Since the nozzle 50 is removable from the spray gun 10, a variety of nozzles can be used to cause the spray gun to generate various spray patterns. Various means can be used to detachably connect the nozzle to the spray gun. In this preferred embodiment, a female threaded cap or bezel 66 cooperates with the threads on barrel 12 to
Connect nozzle to gun.

By changing the shape of the nozzle outlet, various spray patterns are created. 2 and 3 to 6 show two types of nozzles, namely a conical spray nozzle 90.
a (FIG. 2) and the fan spray nozzle 90 (FIGS. 3-6).

The nozzle 90a has a circular discharge port 92a. This outlet is coaxial with the air-fluid mixing chamber and creates a conical spray pattern. The size and angle of the conical pattern can be changed by changing the diameter of the outlet.

The fan nozzle 90 has an elongated or slot-like outlet 92 and produces a fan spray pattern, ie, a pattern having generally flat sides and a diverging lip, as shown in FIG. The nozzle outlet 92 has a width 94 and a height 9
6. The width 94 is smaller than both the height 96 and the diameter of the mixing chamber, and the height 96 is preferably larger than the mixing chamber diameter.

To facilitate atomization of the flowable spray material, the width 94 of the outlet 92 must be between some upper and lower limits. The lower limit is the average diameter of the particles in the spray material. If the width 94 is smaller than this average particle size, the particles tend to block the outlet 92 and impair the spray pattern.

The upper limit is twice the average diameter of the particles in the spray material. By making the width 94 smaller than this upper limit, only one particle at a time along the outlet height 96 can pass through the nozzle at one time. Preferably, width 94 is about 50% of the average particle size.
Make it big.

Alternatively, the spray material can be selected according to the width 94. The spray material is selected such that the particles in the spray material have an average thickness that is one third smaller than the width 94.

In the present invention, all spray nozzles used with a spray gun should have the same outer shape and dimensions so that they can be easily exchanged from one to another to change the spray pattern. Allow quick and easy replacement. Due to the similarity in structure, the description of the characteristic elements of the fan-shaped spray nozzle 90 shown in FIGS.
It also helps to explain the corresponding features of the conical spray nozzle 90a shown in FIG. Corresponding reference numerals are used to indicate corresponding feature elements, and the corresponding numbers in FIG.
Is attached.

In FIGS. 3 to 6, each nozzle is a main body 1
00, 100 has an outer peripheral surface 102 at the front end,
102 has a frusto-conical shape tapered rearward and outward. The outer peripheral surface 104 at the rear of the nozzle is tapered rearward, inward, and frusto-conical, with a complementary frusto-conical hole 1 formed in the front end of the gun barrel 12.
06 (FIG. 2). Nozzle front and rear surfaces 102 and 104
Is joined to the shoulder 1 extending radially outward facing forward.
08, the shoulder 108 can be engaged by a cap or bezel 66. The cap or bezel is internally threaded and engages with a complementary male thread on the front end of the gun barrel 12 to hermetically seat the nozzle rear face 104 in the complementary bore 106 of the gun barrel. .

Therefore, each nozzle can be quickly and easily removed and replaced with another nozzle. At this time, it is only necessary to remove the cap 66, replace the nozzle, and re-attach the cap, as shown in the phantom line illustration in FIG.

The outwardly tapered rear surface 104 of each nozzle has a notch 110 surrounding it in a circular manner provided for alignment with the gun body air passage 78. , An enclosed air-filled compartment (c
An reinforced or air filled manifold 60 is formed.

To ensure that the flowable spray material flows into the plenum or manifold, a resilient elastomeric O-ring seal 112 (FIG. 2) is cut into the plenum in the rear of the nozzle. It can be seated in a circumferential groove 114 between 110 and the rear end of the nozzle. Ring 112 provides an elastomeric seal at the interface between the nozzle and the gun barrel and complements the metal-to-metal seal established by complementary frustoconical surfaces 104 and 106.

The concentric complementary frusto-conical mating surfaces 104 and 106 of the nozzle and gun barrel allow the sprayer to be oriented vertically, horizontally, or at any intermediate position as required by the sprayer. , Making it easier to rotate the sector nozzle 90 relative to the gun barrel. To facilitate rotation, each fan-shaped nozzle 90 is preferably provided with a pair of wrench flats 116 on its front peripheral surface 102. The wrench flat 116 is suitable for receiving a wrench to rotate the nozzle without completely or only partially loosening the nozzle mounting cap or bezel 66. Preferably, wrench flat 11
6 is equidistant outwardly from the length dimension 94 of the fan spray outlet 92 and is oriented with the opposing substantially flat sides of the fan spray, so that fan rotation with respect to the gun is prevented. It's easy.

The internal structure of the nozzle is particularly critical for achieving the objects of the present invention. In particular, the nozzle has a stepped axial bore therethrough defining a material inlet chamber 120 of predetermined diameter and a smaller diameter air and fluid mixing chamber 122. A forward tapered shoulder 124 is interposed between these chambers. As the pressurized fluid entering chamber 120 passes through shoulder 124 and enters chamber 122, the fluid pressure decreases and the flow rate increases, thereby reducing the flow pressure created in mixing chamber 122. Is established in the chamber 122.

Each nozzle is provided with a plurality of circumferentially-spaced, forward, inwardly inclined air orifices or air ports 126, each of which has a plenum cut 110. To the mixing chamber 122. The forward slope of the air port allows the air passing through the air port to enter the fluid material passing through the mixing chamber in a substantially forward contact. Thus, the air flow complements the fluid flow to reduce the generation of back pressure in the mixing chamber. Otherwise, the back pressure will tend to push the fluid material back and into the air orifice or air port 126. The angle of incidence of air on the fluid material is preferably on the order of about 30 °.

The air orifices or air ports 126 are preferably circumferentially equidistant from one another, and preferably have a complete and uniform mixing of air and flowable material to produce a spray pattern of uniform spray density. Are set so that is secured. In the case of a fan spray nozzle, the air ports are circumferentially spaced from the long axis or dimension 96 of the spray port 92 and air is directly incident on the flowable material forming the diverging edge of the fan spray pattern. Not to be. This ensures the integrity and angle of the sector pattern even when the air and / or fluid pressure changes.

The divergence angle of the fan spray pattern and thus the pattern height is determined by the divergence angle of the internal surface of the nozzle, from the peripheral wall of the mixing chamber 122 to the height dimension 96 of the fan orifice 92. In FIG. 5, the divergence angle of 30 ° is indicated by a solid line, and the divergence angle of 45 ° is indicated by a broken line. The width 94 of the outlet 92 is a function of the size of the particles in the flowable material, as described above, and the height is determined by the area of the outlet and the compressed air orifice 126 flowing through the perimeter wall of the mixing chamber.
Is established such that a predetermined relationship is established with the area of

In particular, the area of the nozzle outlet 92 is the air outlet 1
It should be larger than the total area of 26 so that a pressure drop at the outlet takes place, resulting in a further reduction in the occurrence of back pressure in the mixing chamber 122. Also, the pressure of the flowable material in the mixing chamber 122 should not exceed the pressure of the air introduced into the mixing chamber so that complete and favorable mixing and atomization is achieved. Scientifically accurate, area, dimensions, critical to the proper operation of the nozzle
The pressure ratio has not been determined. The mixing chamber 122 is smaller than the inflow chamber 120, the fluid pressure in the mixing chamber does not exceed the air pressure, and the area of the spray port is
It is considered that the area larger than 26 is sufficient.

The conical spray nozzle 90a shown in FIG.
The same design criteria apply perfectly.

[0060]

In addition, the present invention differs from conventional three-element assemblies in the prior art in that nozzles 90 and 90
This provides the important improvement that a is a single unitary structure. Each nozzle can be manufactured from a single piece of material by a single nozzle maker. By virtue of its design, these nozzles can be manufactured with very large tolerances, thus minimizing machining time. Therefore, these nozzles are very economical to manufacture, easy to use, easy to change from one to another, and are less prone to loss.

The foregoing has shown that the objects and advantages of the invention are realized in a convenient, economical, practical, and simple manner.

The preferred embodiments of the present invention have been described above.
Although described, it will be readily apparent that various modifications, changes, and variations are possible without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a vertical longitudinal sectional view of a spray gun, and a nozzle of the present invention was developed in relation to the spray gun.

FIG. 2 is an enlarged partial cross-sectional view of the front end or nozzle end of the spray gun, wherein the nozzle producing the conical spray pattern is shown, and the contoured spray nozzle of the present invention. To connect to the spray gun.

FIG. 3 is an elevation view of a spray nozzle for generating a fan spray pattern.

FIG. 4 is a side view of the nozzle of FIG. 3;

FIG. 5 is a vertical longitudinal sectional view of the nozzle of FIG. 3;

FIG. 6 is a horizontal vertical sectional view of the nozzle of FIG. 3;

[Explanation of symbols]

 90 Fan Spray Nozzle 90a Conical Spray Nozzle 92,92a Spray Port 100,100a Nozzle Body 102,102a Outer Peripheral Surface 104,104a Outer Peripheral Surface 108 Shoulder 110,110a Depression in Truncated Conical Surface 116 Wrench flat 120, 120a Inflow chamber 122, 122a Mixing chamber 124, 124a Shoulder 126, 126a Air port

Claims (20)

[Claims] 1. An internally mixed air spray nozzle comprising a nozzle body, said body having a stepped bore, a spray port, and a plurality of air ports passing through said body. An inflow chamber with a given cross-sectional area for flowing the flowable material under pressure into the lumen, a mixing chamber with a small cross-section for receiving the flowable material under pressure from the inflow chamber, an inflow chamber A shoulder between the two chambers for reducing the pressure and increasing the speed of the flowable material entering the mixing chamber through the spray chamber at the end of the mixing chamber opposite the inflow chamber, Has a peripheral wall leading to the spray port, and the plurality of air ports are arranged on the peripheral wall of the mixing chamber at intervals in the circumferential direction, and air having a pressure equal to or higher than the pressure of the fluid material is mixed in the mixing chamber. To allow the flowable material to pass through the mixing chamber, wherein the air port allows air under pressure to flow through the flowable material under pressure. An internal mixing air spray nozzle, which is inclined in a direction toward the spray port for mixing with the material and discharging the mixture as a spray from the spray port. 2. The spray nozzle according to claim 1, wherein the spray port has a larger cross-sectional area than the total cross-sectional area of the air port. 3. The spray nozzle according to claim 1, wherein the spray port is circular to discharge the spray in a conical spray pattern. 4. The spray nozzle according to claim 1, wherein the spray outlet comprises a slot having a long axis and a short axis for discharging the spray in a fan-shaped spray pattern. 5. The spray nozzle according to claim 4, wherein the air ports are circumferentially spaced from the plane of the long axis of the spray port. 6. An air port having a width of about 30 to the peripheral wall of the mixing chamber.
The spray nozzle according to claim 1, wherein the spray nozzle is inclined by an angle of °. 7. The spray nozzle according to claim 1, wherein the air ports are arranged at equal circumferential distances from each other. 8. The spray nozzle according to claim 7, wherein there are six air ports. 9. The spray nozzle according to claim 1, wherein the spray nozzle comprises only a single integral body. 10. An internally mixed air atomizing nozzle comprising a single, generally cylindrical, integral body having front and rear ends for receiving into complementary mating holes in a spray gun. A rearward, inwardly tapering frusto-conical surface at the rear end, a depression along the circumference of said surface defining an annular compressed air compartment at said surface, a stepped lumen. Extending axially through the body to define a flowable material inflow chamber near a rear end of the body, a flowable material and air mixing chamber near a front end of the body, and an intervening shoulder; The cross-sectional area of the chamber is larger than the cross-sectional area of the mixing chamber;
A stepped lumen, a spray port at the front end of the body, the mixing chamber having a peripheral wall leading to the spray port, a plurality of, circumferentially spaced air ports, An air port extending from the air compartment to the mixing chamber through the peripheral wall of the mixing chamber, and inclining radially inward and axially forward from the air compartment into the mixing chamber; Characterized by an internal mixed air spray nozzle. 11. The spray nozzle according to claim 10, wherein the spray port has a larger cross-sectional area than the total cross-sectional area of the air port. 12. An air port having a width of about 3 to the surrounding wall of the mixing chamber.
The spray nozzle according to claim 10, wherein the spray nozzle is inclined by an angle of 0 °. 13. The spray nozzle according to claim 10, wherein the spray port comprises a slot having a long axis and a short axis for emitting a fan-shaped spray pattern. 14. The spray nozzle according to claim 13, wherein the air ports are circumferentially spaced from the plane of the long axis of the spray port. 15. The cylindrical body of the nozzle and the frusto-conical surface of the body accommodate rotation of the nozzle relative to a spray gun to change the direction of a fan spray pattern relative to the spray gun. A spray nozzle according to claim 13. 16. A cylindrical body of a nozzle in front of said frusto-conical surface extends radially outward to receive a cap for securing the nozzle to a spray gun,
The spray nozzle according to claim 10, comprising a forward-facing shoulder. 17. A method for atomizing and atomizing a fluid material, comprising: introducing a fluid material under pressure into an inflow chamber of a given cross-sectional area, and directing the fluid material from the inflow chamber through an intervening shoulder. Flow through a mixing chamber having a smaller cross-sectional area than the chamber, reducing the pressure of the material as it passes through the inflow chamber into the mixing chamber, and increasing the flow rate, Is introduced into the mixing chamber through a plurality of circumferentially spaced air ports into the mixing chamber, and the air flowing from the air ports into the mixing chamber flows through the mixing chamber. In this direction of flow, the mixture of fluid material and air is expelled from the mixing chamber through a spray port having a larger cross-sectional area than the total cross-sectional area of the air port, so that the fluid material is in the form of a spray. Discharging from a spray port, how to. 18. A barrel, a frusto-conical hole at the front end of the barrel, a nozzle mounting bezel concentric with the hole, a fluid material inlet coaxial with the hole and opening into the hole, the fluid material inlet. An internally mixed air spray nozzle for use with an air spray gun having a compressed air supply passage leading radially outwardly into said bore, said nozzle having a generally cylindrical nozzle body having a front end and a rear end. A concentric frusto-conical surface at the rear end of the body, which may be complementaryly and consistently engaged with the frusto-conical hole, forward of the body, which may be engaged by a spray gun bezel for mounting a nozzle to a barrel. Facing the shoulder, an axially aligned bore with the fluid material inlet of the gun barrel, an axially extending lumen within the body, a concentric centered frusto-conical surface of the body aligned with the air supply passageway within the gun barrel. Circle A recess along the circumference, the recess defining an annular charge compartment concentric with the lumen at a rear end portion of the body, and a front end portion of the lumen inclined inwardly forward from the charge compartment. An internally mixed air spray nozzle comprising: a plurality of circumferentially spaced air ports; and a spray port at a front end of said lumen. 19. A cross-sectional area of the front end portion of the lumen is smaller than a cross-sectional area of a rear end portion of the lumen, a cross-sectional area of the spray port is larger than a total cross-sectional area of the air port, 19. The spray nozzle according to claim 18, wherein the air port is inclined at an angle of about 30 with respect to the lumen. 20. A spray port comprising a slot having a long axis and a short axis for emitting a fan spray pattern, wherein air ports are circumferentially spaced from a plane of the long axis of the spray port. The spray nozzle of claim 18, wherein the frusto-conical surface is adapted to rotate the nozzle relative to the gun barrel to change the direction of the fan spray pattern relative to the spray gun.