Fiberglass Spray Nozzle

FIG. 1 shows a side view of a preferred embodiment of the present invention with a partial cross sectional view of the nozzle housing.

FIG. 2 shows a front view of the embodiment illustrated in FIG. 1.

FIG. 3 shows a top view of a portion of the embodiment illustrated in FIG. 1 along with the resulting spray flow pattern.

FIG. 4 shows a crosssectional view of the spray flow pattern illustrated in FIG. 3 taken along on axis laterally perpendicular to axis A shown in FIG. 4.

FIG. 5 shows a front view of a modification of the embodiment shown in FIG. 2 according to another embodiment of the present invention.

FIG. 1, which illustrates a preferred embodiment of the present invention, shows a unitary nozzle housing 10 having resin nozzle means 20, catalyst nozzle means 30, and control air nozzle means 40 therein. Nozzle housing 10, for example, may be readily attached to the spray gun of a commercially available fiberglass spraying apparatus for fiber-reinforced or gelcoat operations, such as the Magnum manufactured by the assignee of the present application, Graves Spray Supply, Inc. of Goshen, IN. Although these three nozzles means are illustrated within a unitary housing, the present invention also contemplates the use of separate housing means for each nozzle means.

In a particularly advantageous embodiment, nozzle housing 10 is formed with side fan wings 12 on the forward face thereof and disposed laterally of resin nozzle means 20 and with control air supply port 14 and catalyst supply port 16 on its inward or rearward face. Generally, two opposing wings are employed in fiberglass spraying devices according to the present invention. However, in certain gelcoat spraying where only a single wing is necessary. Connected to and upstream from each of these supply ports respectively are supply control means 13 and 15. As these control means and supply port arrangements may be of types generally well known in the art, they will not be discussed in detail herein. Another advantageous feature of the present invention is the inclusion of pressure equalizing means 18 in nozzle housing 10 to form a liquid resin chamber between resin supply means 17 and bearing means 19, adjacent resin nozzle means 20.

Resin nozzle means 20 can be a separable unit inserted into housing 10 and includes tip 22 having nozzle opening 24 therein. Tip 22 may, for example, be formed from a hardened steel or other material resistant to abrasion by liquid resin. It has been found to be advantageous to form nozzle opening 24 by an angular cut 15.degree. to 80.degree. wide in forward portion of tip 22 such that a central oval opening is created. This opening is large relative to nozzles of conventional paint sprayers to compensate for the greater viscosity of fiberglass resin. Nozzle opening 24 permits resin to spray forwardly as stream 26 having a longitudinal flow axis A. By enlarging the orifice size, a greater volume of resin can be sprayed at a decreased pressure. However, it has generally been found to be necessary that a predeterminable minimum fluid pressure is maintained, depending upon fluid viscosity, in order to produce a flattened or oval spray flow even from an oval nozzle. In particular embodiments of the present invention, it has been found to be advantageous to supply polyester resin at a pump delivery pressure of only 180-250 psi and gelcoat resins at a pump delivery pressure of only 400-1000 psi.

In less complex embodiments of the present invention catalyst nozzle means 30 includes two nozzle openings 32 and 34 each mounted on fan wings 12. These nozzle openings are spaced apart from resin nozzle opening 24 laterally and disposed longitudinally downstream along flow axis A. Although the figures show a plurality of fan wings, the present invention also contemplates that only a single fan wing may be necessary when used in, for example, some gelcoating operations. With two fan wing embodiments, it has often been found to be advantageous to align openings 32 and 34 oppositely of each other and directed along the flow of resin spray stream 26 in a plane C perpendicular to that flow, as shown in FIG. 1. Nozzle openings 32 and 34 are formed by angular cuts from 5.degree. to 120.degree. wide in the forward surfaces of fan wings 12 such that central oval openings are created. These openings permit catalyst to spray out along streams 36 and 38 to intersect and thoroughly mix with the flattened resin stream 26 downstream of the resin nozzle means. Fluid catalyst may be atomized prior to spraying through openings 32 and 34, by, for example, premixing with air upstream from housing 10. In order to prevent the release of excessive catalyst fumes in the work area and to improve resin-catalyst mixing, catalyst nozzle openings 32 and 34 should be spaced apart from control air jets by a discrete distance. This spacing should be such that the catalyst spray does not intersect the control air and that the distance between the control air-resin spray intersection and the catalyst-resin spray intersection is not less than 0.25 inch (0.63 cm). In particular embodiments, the optimum distance between such intersections has been found to be about one inch (2.54 cm).

In other embodiments of the present invention control air nozzle means 40 includes a plurality of openings 42 and 44 each mounted on fan wings 12. Openings 42 and 44 may be spaced apart laterally and disposed longitudinally along spray stream 26 from both resin nozzle means 20 and catalyst nozzle means 30. It has also been found to be advantageous to position openings 42 and 44 oppositely of each other and directed along the flow of resin spray stream 26 in a plane at a 15.degree. to that flow and laterally aligned with openings 32, 34 and 24 along axis D, as shown in FIGS. 1 and 2. Openings 42 and 44 are formed as jet ports for control air in the sides of fan wings 12. These jet ports permit control air to flow as air jets to intersect resin stream 26 at, for example, an acute angle downstream and adjacent to resin nozzle means 20 and upstream from the intersection of resin stream 26 with catalyst streams 36 and 38. Alternatively, air jets may contact resin stream 26 by first rebounding off resin nozzle means 20. It has been found to be advantageous to rebound the control air off the nozzle when the surface area of the resin spray stream emerging from the nozzle is relatively large, i.e., with larger nozzle openings. Control air immediately impinging upon these larger spray streams often requires greater volumes of air to achieve the same amount of spray flow shaping as rebounded control air. The number and size of control air nozzle openings is dependent upon the volume of air and operating pressure sought in particular embodiments. In general, less openings and less control air volume will be necessary where air jets rebound off resin nozzle means 20.

In light of the above description, operation of the present invention will now be readily apparent to those skilled in the art, and, thus, will only be briefly discussed below. The spray nozzle arrangement of the present invention, which combines nozzle opening configuration and intersecting fluid and air flows, permits the formation of a resin-catalyst mixture spray flow 50 having a generally flat, fanned shape at the work area. By adjusting air supply control means 13, the flow of control air through openings 42 and 44 may be altered independently of either the resin or catalyst spray flows to establish predetermined resin-catalyst mixture flow configurations for given resin and catalyst spray supply levels. Since the intersection of control air with resin stream 26 may be spaced apart in a separate stage from the intersection of catalyst streams 36 and 38 with the resin stream, fine tuning of the flow configuration may be achieved merely with air supply adjustment and tails or split fingers in the resulting spray will be avoided. Further, since the resin stream is flattened by control air prior to resin-catalyst spray mixing and under a reduced pressure, the intersecting catalyst spray is much more uniformly mixed with the resin. Thus, a thoroughly mixed, continuous, linear flow fan having a constant cross-sectional width perpendicular to the longitudinal axis of flow A may be created, as shown in FIGS. 3 and 4.

By rebounding the air off the resin nozzle means 20 and intersecting the resin stream at acute angles, the control air bombardment may efficiently atomize the resin spray along longitudinal axis of flow A even as the catalyst spray intermixes. Therefore, the pressure on the fluid resin upstream from resin nozzle means 20 may be decreased and/or the size of opening 24 increased with no loss of spraying efficiency. The air flow control system of the present invention is particularly effective with viscous polyester resins which would ordinarily resist spray flow flattening. An advantageous feature of the present invention is to permit a large volume of fiberglass mixture to be laid evenly and smoothly over the work piece.

Further, the formation of such fan shaped spray flows may be aided by the presence of pressure equalization chamber 18 upstream from resin nozzle means 20. This chamber helps remove turbulence and nonlaminar flow in the resin spray which would tend to create noncontinuous spray mixture flows.

FIG. 5 shows a further embodiment of the present invention which employs additional control air openings 41 and 43 adjacent opening 42, openings 45 and 46 adjacent opening 44 and openings 47 and 48 disposed oppositely of each other on forward face 11 of housing 10 along axis E, perpendicular to alignment axis D. These additional openings permit further adjustment and fine tuning of the configuration of mixture flow 50. Control air openings 41-46 serve to define spray flow along the minor axis of the fan; control air openings 47 and 48 serve to define spray flow along the major axis of that fan. Again, these additional openings produce control air which either rebounds off of resin nozzle means 20 or which intersect the resin spray stream directly.

Although the present invention has been described above in detail, the same is by way of illustration and example only and is not to be taken as a limitation. The spirit and scope of the present invention are limited only by the terms of the appended claims.