Dispensing – Plural sources – compartment – containers and/or spaced jacket – With common discharge
Reexamination Certificate
1999-04-08
2001-02-27
Shaver, Kevin (Department: 3754)
Dispensing
Plural sources, compartment, containers and/or spaced jacket
With common discharge
C222S145100, C239S414000
Reexamination Certificate
active
06193110
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for the internal mixing and dispensing of plural component materials, and particularly to an improved apparatus for the internal mixing and dispensing of resins and catalyst of polyester.
BACKGROUND OF THE INVENTION
Multi-component application systems have been used, for example, in manufacturing plastic articles by applying resinous materials to a mold or perform for an article, or to pre-arranged fiber reinforcing materials, or with fiber reinforcing materials as they are being applied.
In multi-component application systems, a liquid resin and a curing agent for the resin are most generally mixed and dispensed into molds or onto articles or preformed substrates where the curing agent and resin react and harden. In spraying applications, the resin and curing agent components are mixed together, either externally or internally of the apparatus, and the mixture is directed onto a substrate, such as a preform, as a plural component spray.
In internal mix systems, the resin and catalyst are mixed within the spraying apparatus, and the mixture is then dispensed by a nozzle and directed onto the substrate. Complete and thorough mixing of the resin and catalyst is vital to avoid non-uniform hardening of the resin on the substrate and other undesirable results. Furthermore, mixed resin and catalyst must be removed from an internal mix apparatus to avoid blockage of the apparatus by cured resin, and such apparatus are generally flushed with flows of compressed air and/or solvent to prevent such blockage.
U.S. Pat. No. 3,799,403 discloses an internal mix dispensing apparatus including a mixing chamber that is movable with respect to the housing of the device. In the disclosed apparatus, moving the mixing chamber to the mix position causes the components of the plural component material to be introduced into the mixing chamber, appropriately mixed and then dispensed; and thereafter moving the mixing chamber to the purge position terminates the introduction of components into the mixing chamber and introduces compressed air into the mixing chamber to substantially purge residue component material from the mixing chamber and its cooperatively associated orifice. In addition, the compressed air can be employed during the dispensing of the mixture of component materials of the plural component material so as to assist in atomizing particles of the material from the terminus of the mixture of plural component material as such material is ejected from the orifice of the device and to assist in shaping the spray pattern of the plural component material particles.
In spraying systems using compressed air, the quantity of air used and its substantially controllable expansion in the workplace can create problems. It is expensive to compress air, and the large quantities of compressed air used by existing systems can impose a significant operating cost on the system. In addition, the blast of compressed air used to atomize liquid components carries a significant quantity of spray particles away from the substrate, wastes the expensive material, creates an unclean spray area, contributes to the problem of operating such manufacturing operations safely and frequently requires overspray collection systems. Furthermore, the use of large quantities of air during operation of the system can often create an undesirable spread of fumes, and create a problem in meeting environmental standards.
In addition, in internal mix dispensers, the failure and wear of internal seals and improper maintenance can result in mixed plural component materials, such as polyester resins, hardening within the dispensing apparatus and requiring its disassembly and repair before it can be satisfactorily operated again.
BRIEF SUMMARY OF THE INVENTION
The invention provides an improved internal mix plural component dispensing apparatus which can be easily disassembled for repair and maintenance and reduces the surfaces that are exposed to mixed plural component material. In the invention, a dispenser body and a movable valving-mixing element are combined so that the dispenser body movably carries the entire valving-mixing element within a central cavity of the dispenser body and the valving-mixing element is movable between a forward dispensing position and a rearward non-dispensing position and is removable from the dispenser body after the removal of a single dispenser body closure.
In one preferred embodiment of an internal mix dispenser of the invention, a dispenser body forms a cavity having a rear portion with cylindrical walls and a forward portion with a pair of opposed planar walls, with the forward cavity portion having a smaller cross-section than the rear cavity portion, and a valving-mixing assembly is movably carried within the dispenser body between a dispensing and a non-dispensing position and is removable therefrom by removal of a single body closure. In one such preferred embodiment, the valving-mixing assembly includes a piston portion at its rear, a spring with a portion being engaged with a transverse wall portion of the dispenser, and a forward valving-mixing portion including a central bore closed at its rear and extending forwardly to an outlet opening, and a pair opposed planar sides, with one passageway extending from one of the planar sides to the central bore, and a second passageway extending from the other of the planar sides to the central bore.
Liquid component delivery means may be fastened to the dispenser body and provide a passageway for delivery of resin and a first seal surrounding the resin passageway that is adapted to seat on the planar side of the valving-mixing portion having the one passageway, and further provide a passageway for delivery of catalyst and a second seal surrounding the catalyst passageway that is adapted to seat on the other planar side of the valving-mixing portion. The first and second seals and the planar sides of the valving and mixing portion cooperate to block the flow of resin and catalyst when the valving-mixing assembly is in the non-dispensing position. The single body closure for the cavity may be removably attached to the rear of the dispenser body, and can form, with said rear portion of the cavity, an air cylinder. Removal of the body closure permits the entire valving-mixing assembly to be removed in one piece from the dispenser body for maintenance and repair of the valving and mixing assembly and the internal surfaces of the dispenser body.
The dispenser body can have a compressed air inlet into its rear cavity portion rearwardly of the piston portion of the valving-mixing assembly so that the admission of compressed air into the air inlet moves the valving-mixing assembly forwardly within said dispenser body to the dispensing position where the first and second passageways of valving-mixing portion are in communication with the resin and catalyst passageways of the liquid component delivery means for the admission of resin and catalyst to the central bore for mixing and dispensing. The forward movement of the valving and mixing assembly reduces the surfaces forwardly of its outlet orifice that are exposed to mixed plural component material, and can compress the spring of the valving and mixing assembly between its piston portion and a transverse wall portion of the dispenser body between the forward and rear portions of dispenser body cavity so that upon release of the compressed air from the rear body, the spring can return the valving-mixing assembly to the non-dispensing position. In preferred dispensers, the dispenser body an include a smaller cylindrical sealing cavity located forwardly of transverse wall body portion and having a diameter intermediate in size between the rear cavity portion and the forward cavity portion, and the valving-mixing assembly can include a sealing plug and O-ring seals forwardly of the spring, sealingly engaging the cylindrical walls of the sealing cavity. The dispenser body can include a second compressed air inlet to the rear cavity forwardly of t
Brinks Hofer Gilson & Lione
Deal David
Glas-Craft, Inc.
Shaver Kevin
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