Note: Descriptions are shown in the official language in which they were submitted.
~ 34~
SPRAYING APPARATUS AND ADAPTOR
WITH EXPENDABLE VALVE ASSEMBLY
This application is a division of Canadian Serial
No. 269,285, filed January 7, 1977. ;
BACKGROUND OF THE INVENTION
This invention relates generally to a spraying
apparatus valve assembly for delivering a component
mixture to the spraying nozzle of a spraying device
and more particularly relates to a valve as~embly and
10 spraying apparatus for mixing and spraying a uniform `;~
blend of two or more-components.
In the art of devices spraying polyester resins and
catalysts to a surface, many methods and processes have
been developed over the past years. These devices have
been successful to some extent, but they have not been
satisfactory for hand-held use in that they have been
typically heavy and cumbersome to use. In addition,
they are generally very complicated and require extensive ~
maintenance work and care. ~ ~ ;
In this particular field, it has been a generally accepted
practice to apply polyester resins and catalysts via a -.
resin pump, catalyst or injector pump, and an air source -~
to the gun and blend together by internal mixing in the ~-
gun nozzle head or external mixing at the surface being `
coated. In the art of spraying two different methods ~`
have emerged. One is low-pressure (under 100 psi) termed `
"air-atomized" process internally mixed at the gun nozzle in
which the catalyst arrives at the gun body from an ~ ~-
air atomized injector providing pre-mixed catalyst and
30 air to the gun. The pre-mixed catalyst and air is ; ``
: ,,~
carried to the gun via suitable hose in an atomized
state. The resin and atomized catalysts are then `~
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~f3.Z347~
-
internally mixed through a grid arrangement in the nozzle section
of the spray gun. This method requires a purging of all passages
including nozzle and body after each use.
The second method uses high pressures and is generally
termed "airless". In this system polyester resin is pumped to the
spray gun and through an orifice or airless V-jet in the gun nozzle
head. Catalyst is also pumped to the nozzle and remains in an
airless state, and in some instances requires dilution with a
compatible agent. Diluted catalyst allows the use of orifices or
V-jets of sufficient size to avoid the frequent problem of plug-ups
coming from small particles. The nozzle head has two or more
V-jet arrangements to form the necessary spray pattern. The V-jets ~
in the nozzle are directed at an angle toward each other allowing -
the catalyst and resin to intersect forming a proper spray pattern. `
In addition to the disadvantages already mentioned, such as high-
pressure plug-ups on the nozzle V-jets, the prior art system
requires extensive maintenance in order to keep them in suitable
condition for continuous use. This requires frequent cleaning in
order to prevent hardening of material clogging the passageways.
Thus, there is a great need for simplicity of design to reduce
maintenance costs and increase the usability of this prior art
system. ;
Also valves for use in spraying devices to mix components
for delivery to spray nozzles are known in the art. However, they`
have not always been satisfactory and~in the case of spraying ~ ~
devices for mixing a catalyst with a resin they have been particu- `
larly experiencing difficulties. For the latter purpose the ~ ~-
present valves mix air with the catalyst for delivery to a nozzle
and simultaneous spraying with a resin. However, it has been
difficult to obtain a proper mixture of air and catalyst ~or com-
,
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~.23~7
bination with the resin to produce the desired result. One such
prior art device has a dual-valve arrangement in which the air
moves a body away from a second orifice permitting the catalyst
to mix with the air. While this valve arrangement has achieved
some success, it is not suitable for low-pressure requirements
because the valve body tends to chatter or vibrate. The present
invention solves the problems of prior valves and provides a
smooth, easily controlled mixing assembly.
SUMMARY OF THE INVENTION
. . _ _ .
The disclosed invention seeks to provide a valve assembly
which permits controlled mixing of two components and in
particular provides controlled mixing of air with a catalyst for
delivery to a feed tube which efficiently mixes two components;
which can be easily disassembled for repair and replacement;
which operates smoothly and efficiently over a wide range of
pressures; and which is readily adaptable to existing devices.
The disclosed invention further seeks to provide a spray
gun system utilizing the novel valve assembly which is
uncomplicated in design and has a minimum of parts, and which is
safe, dependable, lightweight and efficient in use.
Additionally the disclosed invention seeks to provide a spraying
apparatus for spraying two or more components; which is
efficient and easy to use; which provides separate housings for
valves to simplify maintenance and repair problems; which has a
simple and efficient mixing chamber in the gun body; which
utilizes a simple expendable "core valve" for delivering
catalyst to the mixing chamber; and in which a removable nozzle
provides a uniformly directed spray.; Still another aspect of
the disclosed invention seeks to provide a spraying apparatus for
delivering two or more fluid components; that utilize the
advantages of applying "airless" resin for complete control and
"catalyst air mixture 1l, at low pressure with catalyst being
attracted to the fan pattern of resin due to its higher velocity
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~.23~7
and vacuum at that point, thus avoiding overspray and fumes;
which uniformly blends the premixed catalyst and components
outside of the spraying gun; and which requires no purging or
flushing means eliminating the fire hazard and expense of
solvent. ;
The novel valve assembly of the present invention is
comprised of a chamber having a valve housing secured internally
to provide a passageway between the exterior of the housing and
the chamber wall for air to pass through the chamber. In the
center of the body is mounted a core or stem valve which
releases a component or catalyst into the outlet side of the
chamber for mixing with a second component such as air. The
flow of air is controlled by a main valve operated by the
trigger of a spraying device, while the trigger simultaneously
operates a mechanical plunger or push rod to open the core or
stem valve.
The rate of flow of the components, such as air, and a
catalyst is readily controlled by the push rod acting on the ~
stem of the core valve. One advantage to this valve assembly is -
that the chamber, housing and core valve can easily be
disassembled for cleaning and the core valve can be quickly
replaced, if necessary. When the valve assembly is attached to `-
or incorporated in a spraying device, the valves in the spraying ;
device simultaneously operate with the core valve per~itting the
air-catalyst mixture to be discharged through a nozzle of the
spraying device while a resin is simultaneously discharged -
through a second nozzle. The valve assembly can be mounted in a
housing or fitting which is readily adaptable to be attached to
all spraying devices in common use to-day.
More particularly the spraying apparatus which utilizes ~-
the novel valve assembly has an improved method of spraying and -
applying resins, catalysts, and air, eliminating some of the ~ ;
difficulties and disadvantages of prior systems. Utilizing the
advantages of both "air atomized" and "airless" for this ~ ;
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34~
purpose the spraying apparatus of this invention is provided
with a spray gun body to which a nozzle body is attached. The
nozzle body has one valve for delivery of a resin to a removable
nozzle, while the gun body has a second valve for delivering a
mixture to the nozzle through the nozzle body. This permits
valves for delivering the resin and catalyst to be separated and
in separate housings so that they may be individually replaced,
repaired or cleaned. m e mixing chamber in the gun body
incorporates features of the novel valve assembly. That is, the
gun body has a mixing chamber housing a core valve for
delivering the catalyst to the mixing chamber along with a
supply of low-pressure air. The air is delivered to the mixing
chamber through the outer portion of a coaxial cable and flows
into the chamber through apertures in a flange supporting the
housing for the core valve. The core valve is operated by a `
rod attached to the valve for releasing the mixture through the
nozzle to the nozzle body.
The nozzle body is secured to the gun body by a hollow
tubular nut which has a threaded nipple for attachment of a
conduit carrying a resin. The resin ~lows at medium pressure
(800 psi) airless condition through the hollow tubular nut to
the nozzle body into a chamber in the nozzle body and then
through a first valve to a central aperture of the nozzle. Air
and catalyst are delivered to a coaxial cable to the mixing
chamber through the core valve and the passageways on the flange
surrounding the housing for the core valve. A second valve
releases the mixture from the mixing chamber through the gun
body to the nozzle body and then to a pair of apertures on
opposite sides of the resin aperture in the nozzle. This second
3~ valve is simultaneously operated with the first or resin valve
and in turn operates the core valve for mixing of the air and
catalyst in the mixing chamber. The pair of apertures in the
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nozzle are angled toward the center airless V-jet aperture so
that a uniform spray of low pressure catalyzed mixture
intersects the resin close to the nozzle of the spray gun.
The three apertures are arranged in the nozzle to produce a fan-
like uniformly blended spray of resin and atomized catalyst.
In this divisional application, the invention pertains to
the nozzle jet assembly which includes at least one nozzle jet ;
adapted to spray a fluid component in a substantially planar fan-
shaped pattern and a second nozzle jet adapted to spray a fluid
component in a substantially planar fan-shaped pattern. Mounting
means mount the nozzle jets whereby the fan-shaped patterns from
each jet intersect each other at a predetermined distance beyond
the nozzle jets for mixing. The mounting means include a nozzle
body having a plurality of passageways for delivery of a plurality
of fluid components to the nozzle jets. An annular groove in the ;~
nozzle body is in communiGation with the passageways and the at
least one jet and a bore located inside the annular groove is in
communication with the passageways and the second jet. Inter-
locking means interlock the jets so that the fan-shaped pattern
produced by the two jets may be simultaneously rotated to any
- desired angle without affecting the orientation of the fan-shaped
pattern from each jet whereby communication between the nozzle
body and the nozzle jets is maintained constant regardless of the
angular orientation of the jets.
Other advantages and novel features of the invention
will become apparent from the following detailed description of
the invention when considered in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OE THE DRAWINGS
FIGURE 1 is a side elevation of the mixing valve
assembly adapted to a spraying device. -~
FIGURE 2 is a top elevation of the valve assembly taken
at line 2 - 2 of Figure 1. ;
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7~
FIGURE 3 is a sectional view of the valve assembly taken
at 3 - 3 of Figure 2.
FIGURE 4 is a partial sectional view of the valve
assembly taken at 4 - 4 of Figure 3.
FIGURE 5 is a side elevation of the spraying apparatus
- of the invention.
FIGURE 6 is a cross sectional view of the spraying
apparatus of Figure 5.
FIGURE 7 is a view taken at 7-7 of Figure 6.
FIGURE 8 is a view taken at 8-8 of Figure ~.
FIGURE 9 is a sectional view of the nozzle assembly
taken at 9-9 of Figure 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the manufacture of thermo setting plastic products, a
spraying device 10, as shown in Figure 1, having a pair of
nozzles 12 and 14 for simultaneously spraying two components,
such as a catalyst and a resin, is required. The amount of cat-
alyst delivered to nozzle 12 is carefully controlled by first
mixing it with air in a mixing valve assembly 16 which is the
.
subject of the present invention. The mixing valve assembly 16
is shown in Figures 1 and 2 as an attachment to existing spray ~
devices. The heart of the mixing valve assembly is the mixer `
housing 20 which has a chamber 22 in which is secured a body or
valve housing 24, which is securely held in the chamber 22 by a
fixture or hose fitting 26. The housing or body 24 has a ,
threaded central bore 30 in which a core or stem operated valve
28 is installed. The opposite end of the housing 24 narrows
down to an inlet tube 32 for connecting a hose 34 in line with
the core valve 28. The valve housing 24 is shaped to fit the
chamber 22, as shown in Figure 4.
In the sectional view of Figure 4, the chamber 22 is
shown as cylindrical while the housing 24 has a square cross- -~
sectional shape. The chamber 22 is constructed with a ridge 40
against which the corners of the housing 24 abut to securely hold
~.. . ... .
3~77
the housing in the chamber 22. Also, the inside diameter of the
fitting 26 at 42 is slightly less than the diagonal dimension of
the housing 24 so that when the fitting 26 is screwed into the
mixing housing 20, the valve housing 24 is secured between the
ridge 40 and the end 42 of the fixture 26. Thus, when fitting
26 is removed from the mixing chamber housing 20, the valve
housing easily slides out of the chamber 22 and the core valve 28
can be easily removed for cleaning, repair or replacement. Thus
the core valve 28 is an expendable valve assembly independent of
the housing 2n. That is, the expendable valve assembly or core
valve 28 can be easily removed and discarded without discarding
the housing 20.
Air or a second component is delivered to the chamber 22
through a second hose 44, coaxial with the first hose 34, and ~
attached via fittings 46 and 48. Thus, air or a second component -
is delivered, as shown by arrows, to the chamber 22 through
passageways 36, simultaneously with a catalyst or first component
being delivered to the chamber 22 through hose 34 and core valve
28. The core valve 28 is similar to a tire core valve and is `
operated by a stem 50 which, when moved to the right, displaces a -
collar 52 from the valve seat 54, permitting the catalyst to flow
through the valve into the chamber 22 to be mixed with the air.
. ~ .. :
In order to adapt this new mixing valve to existing
spraying devices, the offset arrangement of the feed tube is
provided. The feed tube 18 is connected to a ported bolt 56
fitting in the offset socket portion 58 of the mixing chamber
housing 20. The air-catalyst mixture is delivered to the feed
tube 18 through a passageway 62, leading to a port 64 in the bolt
56, which is sealed by O-rings 60.
The core valve 28 for delivering the catalyst to chamber ~ ;
22 is operated by a plunger or push rod 66 engaging the end of
the stem 50 of the core valve 28. The plunger 66 is biased by a
spring 68 and is secured in the mixer chamber housing 20 by a cap
70 and a split washer 72 installed on grooves in the plunger 66.
g _
3~7~ `
The push rod mechanism 66 is sealed by O-rings 74 at either end o~
the spring 68. A button 76 is adjustably attached to the push rod
66 by an Allen screw 78. The Allen screw 78 permits adjustment
of the button 76 to compensate for wear on the collar 52 of the
core valve 28, if necessary.
For operation with existing spray devices the mixing
valve assembly 16 may be attached to an existing spray device
10, for example, as shown in Figure 1. The feed tube 18 screws
into a main valve 80 connected to the nozzle 12. In most cases
the feed tube 18 is an existing part of spraying devices and has
a hexagonal threaded end 82 for attachment of a hose fitting.
In this case the ported bolt 56 screws into the hex end 82 of
the feed tube 18, as can be more clearly seen in Figure 3.
Nozzle valve 80 is operated by a trigger 84 which moves rod 86
in and out. The button 76 on the valve assembly 16 is
positioned to engage the end of the rod 86 when the trigger 84
is operated. In operation, trigger 84 moves rod 86, opening -
valve 80, permitting air to flow through valve assembly 16 to
the nozzle 12. Simultaneously with the opening of valve 80, a
valve (not shown) is opened to permit resin to flow to nozzle
14. In addition, the trigger 84 simultaneously operates plunger
66 to open core valve 28, allowing the air flowing around valve -
housing 24 to mix with the catalyst in chamber 22 to produce a
mist which is then discharged through valve 80 and nozzle 12.
The valve assembly 16 allows two or more fluids from
separate sources to blend or mix together in chamber 22 for ap-
plication by a spray device 10, commonly used in the industry.
The valve assembly described allows two or more fluids or compo-
nents to be mixed together prior to delivery to a primary valve
80 and controlled by this valve. The principle of simultaneous
operation of the valve assembly 16 permits it to be used either
fore or aft of the primary valve 80 or in tandem. In the
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3477
embodiment shown in Figure 3, the casing or mixing chamberhousing 20 encloses a valve housing 24 of square or other
irregular shape, which is installed in the cylindrical conduit
or chamber 22 creating equal passages 36 for the first component
(i.e. compressed air) to flow through. While the valve housing ;
24 is shown as square and the chamber 22 as cylindrical, obviously
other shapes would be suitable. That is, the chamber could be
square and the housing cylindrical, or the housing could have
only one flat surface between a curved surface of a chamber.
It is only necessary that the exterior shape of the valve
housing 24 and the interior shape of the chamber 22 be such
that when the housing 24 is installed there will be one or more
passages of sufficient size to permit free flow of air between
the housing and the interior wall of the chamber 22.
With the valve assembly shown there is no need for adding
diluting agents to a catalyst, such as methyl, ethyl, ketone,
peroxide (MEKP) with ethyl acetate or the like to achieve
proper percent of catalyzation with the resin and additionally
a suitable spray pattern can be obtained with optimum pressure.
The present invention also allows the blending of compressed air
at low pressure with straight (60%) undiluted MEKP. This
results in proper percentage and uniform catalyzation over a
uniform spray pattern. This valve assembly also eliminates the
fire hazards of MEKP and ethyl acetate, partucularly when
blended together, providing a safer working environment for
the industry as a whole. The concentric valving of the two compo-
nents and the valve housing and chamber also permits straight
line flow permitting use of coaxial hose offering the advantages
of a single hose rather than the more common two-hose arrangement.
Also, this valve assembly can be adapted to or built into spray
devices having two or more nozzles, if desired.
3~7'7
A spraying device having the valve assembly built in as
shown in Figure 5 and is comprised of a gun body 110 to which a
nozzle body 112 is attached having a removable nozzle 114. The
gun body 110 has a handle 116 and a trigger 118. Conduits 120
and 122 deliver the fluid components usually polyester resin,
catalyst and air. The nozzle 114 delivers fan-like sprays of
catalyst and resin to produce a planar spray which will cover
a broad area when the plane is perpendicular to the direction in
which the spraying gun is being moved or will produce a relatively
thin line when the plane is parallel to the direction of move-
ment of the spraying gun.
The sectional view of Figure 6 illustrates the relatively
uncomplicated nature of the spraying apparatus which delivers
resin and catalyst to the nozzle and also mixes the catalyst with ;
air in the body 110 of the gun. Conduit 122 is a coaxial type
which simultaneously delivers air and catalyst to a mixing chamber
124 i~ the gun body 110. Conduit 122 attaches to the gun body by
a threaded nipple 126 internally threaded into the gun body and
externally attaching to a coupling 128 on the coaxial conduit 122. ;
A core valve 132 is threaded into the housing in the same manner
as was discussed with respect to the add-on valve assembly above. `; -
The housing 130, however, is secured in the mixing
chamber 124 by a flange 134 which butts against the internal end
of nipple 126. A spring 136 biased against the flange 134 main-
tains the housing 130 securely in place. The opposite end of
spring 136 is biased against a flange 138 which is a part of valve
140. A rod or post 142 maintains the spring 136 in position ;
between the housing 130 and the valve 140. The valve 140 has a
resilient valve seat 144 engaging the flange 138.
:;
- 12 - ~
,: ',
~ 3~77
,
The valve 140 formed by valve seat 144 and flange 138 are
all supported in a threaded valve housing 146. The valve 140 i~
operated by a plunger 148 passing through the valve housin~ 146
which is sealed externally by a cap 150. The valve housing 146
has a passageway 152 for releasing the mixture from mixing
chamber 124 to a passageway 154. The valve housing 146 has an
undercut portion in the area of the aperture 152.
The resin conduit 120 is attached to the gun body 110 by
~, . ...
a coupling 158 which screws onto the threaded nipple 160 of ~-`
elongate hollow nut 162. The elongate hollow nut 162 provides a
passageway 164 to the nozzle body 112. The other end of the
hollow elongate nut 162 has a threaded end 166 which screws into -~ ~
a tapped hole 168 in the nozzle body 112. The passageway 164 is ~ ;
thus in communication with passageway 170 in the nozzle body which
delivers resin to a chamber 172, for delivery to a nozzle head
assembly 114 through the resin valve assembly 174. When the
nozzle body 112 is attached to the gun body 110 by threading into ~ -
the nut 162, a hollow bushing 176 aligns and seals the catalyst ~ -
mixture passageway 154 with passageway 178`in the nozzle body 112. '~
A flange 180 on the bushing 176 seals the catalyst mixture passage~
way 154 and 178.
Valve assembly 174 is comprised of a valve seat 182 and
plug 184 attached to a shaft 186 for operating the valve. me plug ,~-
184 is bias closed by a spring 188 between the plug 184 and
:
a valve housing 190 threaded into the nozzle body 112. A
threadèd bushing 192 holds a Teflon seal 198 in the interior of
the housing 190 for sealing around a shaft 186. An adjustable -
trigger pull bushing 194 is secured to the shaft 186 by a screw ' ~`
196. Flanges on either end of bushing 194 are engaged by the
trigger 118 for operating the resin valve assembly 174. This ~ `~
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~ Z347~
bushing 194 also engages the shaft 148 for operating valve 140
and core valve 132. A clean-out plug 200 is provided in the
nozzle body 112 for purging chambers 170 and 172 of collected
resin.
The nozzle assembly 114 is comprised of a nozzle head 202
secured to the nozzle body 112 by a lock nut 204. Secured between
the nozzle head 202 are a pair of bushings 206 and 20~ providing
passageways communicating with the nozzle resin valve assembly
174. Thus, the nozzle assembly 114 has two parts, a catalyst
head 202 and a resin head 208 which may be removed and separately
replaced, if desired. The resin head 208 has centrally located
aperture in the form of a V-jet which is sho~n more clearly in
Figure 7, 210. The catalyst head 202, however, has a pair of
extended jet openings 212 and 214 for spraying a catalyst mixture
into the resin spray.~ Thus, passageways 216 and 218 communicating
respectively with said openings 114. The catalyst mixture is
delivered to a circumferential or circular recess 220 in the face -~
222 of the nozzle body 112 by passageway 178. O-ring seals 224
and 226 seal the catalyst passageways.
The trigger 118 is hinged at 230 which is a pin attachment
to the gun body 110. In operation air and catalyst are delivered
through the conduit 122 to the mixing chamber 124 with the cata-
lyst being supplied through the central conduit 123 and air
flowing around the housing 130 into the chamber 124. When the
trigger 118 is operated, it forces plunger 148 to the left,
opening valve 140 and core valve 132, thus releasing catalyst to
the chamber 124 for mixing and at the same time allowing the
mixture to flow into passageway 154. At the same time, trigger -
118 opens, resin valve assembly 174 releases resin delivered
through conduit 120 and hollow nut 162 to the nozzle assembly
;
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~! , . , , . ' ' ': . . .
3~7~
through nozzle body 212. As can be seen from Figure 7, the jets
210, 212 and 214 of the nozzle assembly 114 are like V-jets which
produce a fanshaped spray with the catalyst mixture intersecting ;
the resin at a point close to the exit point from the nozzle
assembly 114. This action produces a blended, uniform spray for
coating the surface being sprayed.
The center nozzle 208 for the resin is keyed or indexed
to the outer nozzle 202 for the catalyst by a slotted hole 203
engaging the flat sides of the resin nozzle. Thus, whenever the
entire nozzle 114 assembly is rotated on the gun, the V-jet 210
of the resin nozzle 208 will always remain parallel with the
V-jets 212, 214 of the catalyst nozzle 202. Thus, rotation of
the nozzle assembly to change the spray pattern from horizontal
to vertical will maintain the fan patterns substantially parallel.
Without the keying of the resin nozzle 208 to the catalyst
nozzle 202, removal and replacement of the resin nozzle would
cause difficulty in aligning the fan pattern produced by the V-
jets. The keying eliminates the need for adjusting the resin
nozzle to the fan pattern of the catalyst nozzle. In some prior
art spray guns this has been a problem. -
- Appropriate O-rings are provided with each valve assembly
and at the mating points of the nozzle body 112 with the gun body
110 in the usual manner, such as is shown at 232 for the nozzle
assembly 234 for the resin valve assembly 236 for the resin
hollow nut 162 and 238 for the catalyst mixture bushing 176 for
attaching the nozzle body 112 to the gun body 110. O-rings 238,
240 and 242 seal the catalyst mixture valve 140. O-rings 244
seal the coaxial conduit nipple 126 to the gun body 110.
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47~
The spray gun does not require an atomized-type injector
vessel. Undiluted catalyst may be delivered to the gun via the
coaxial hose arrangement 122 from a container (not shown) having
a flow meter attached. The inner hose 123 carrying catalyst, the
outer hose carrying regulated air. These two components arrive
at the gun body 110 and are mixed together simultaneously in the
core valve assembly and mixing chamber 124 within the gun body 110.
From the mixing chamber 124 it is th~en led forward through a
single hole to the gun nozzle 114 and is applied through two
orifices 212 and 214, at 10 angles to the resin in a fan pattern
both below and above the resin fan pattern. The nozzle may be
rotated with resin V-jet 210 remaining in place so that the fan
pattern and catalyst are always in proper relation to each other.
In the case of applying gel coat resins, it is an advantage to be
able to rotate the complete gun no-zzle for best pattern position.
Resin is pumped to the gun used in an airless method.
Pressures may be as low as 450 pounds to 3500 pounds. The common
airless V-jet is used at the nozzle and orifice size is determined -;;
by the gun operator.
In the above sequence, it is quite simple to effect
perfect catalyzation by use of two air regulators - one to govern
the amount of air used to mix and spray, and the other to regulate
the pressure above the catalyst in the container having a flow
meter attached. This arrangement eliminates delay in a blended
mixture arriving immediately at the spray nozzle. Due to the
unique design, assembly and~disassembly takes just minutes as the
catalyst valve is an expendable, easily accessible core valve
assembly.
While most spray guns involve three or four hoses to
- 16 - ,
3~7~
operate, this improved method uses only two and no solvent
flushing means is required which in itself presents quite a saving.
A feature best suited to safety of operation is the
advantage of low-pressure resin being sprayed airless and, of
course, the catalyst also being applied at low pressures of around
12 to 20 pounds with no overspray fumes. Catalyst air mixture
is drawn at 10 toward the resin fan pattern, by the velocity
of the resin flow. Thus, catalyst overspray is avoided.
Obviously, many modifications and variations of the
invention are possible in light of tne above teachings. It is
therefore to be understood that the full scope of the invention
is not limited to the details disclosed herein and may be
practiced othen~ise than as specifically described.
,".: ~,:.,.
