Apparatus for dispensing of two component adhesive from a static mixer

Abstract: An apparatus for dispensing of two component adhesive utilises a conventional static mixer which is supplied with an insert (12) providing a reduced outlet diameter source to allow streaming of the adhesive from the mixer.

Description: While static mixers for dispensing (robotically or otherwise) two component adhesives are generally well known and include those of the type manufactured by TAH, such tips have typically provided an extruded stream which requires that the dispense tip be located fairly close (on the order of 1.2 times the bead diameter) to the part on which the adhesive is being applied. Such a small standoff distance requires careful programming of the robot path in order that proper standoff distance be maintained. US Patent No. 5478150 discloses a device for the continuous monitoring of the correct proportioning and mixing of at least two fluids in a mixing device. The device comprises a plurality of mixing elements and a nozzle according to the preamble of claim 1. A solid insert is provided in the nozzle so that fluid passes around the outside of the insert. It is an object of this invention to provide a two component static mixer adhesive dispensing device which is easily and inexpensively manufactured and which is capable of being utilised at substantially increased standoff distances compared to the current prior art devices. These and other objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. Figure 1 is a perspective view of the instant invention. Figure 2 is a sectional view of the instant invention taken along line 2-2 of Figure 1. Figure 3 is a sectional view of the instant invention taken along line 3-3 of Figure 2. Figure 4 is a perspective view of the insert of the instant invention. The instant invention is generally designated 10 and is comprised of a bullet shaped insert 12 which has a through discharge hole 14 of less than 2.3 mm (0.090 inches). This insert is placed inside the discharge end 18 of the standard static mixer 16 which usually has a discharge orifice of 2.3 mm (0.090 inches) or greater. For the same desired flow rate, a higher discharge pressure will be required to pass through the smaller discharge orifice. Such a higher pressure thereby creates a higher adhesive exit velocity which in turn creates a stream which can be directed at the substrate at a greater standoff distance. The higher pressure will at least in part be provided by the more restrictive orifice but increased system pressure may be required as well. In the preferred embodiment, the static mixer shroud 20 contains twenty four mix elements 26 and has an inside diameter of 9.5 mm (3/8 inch), and a discharge orifice diameter of 3 mm (0.120 inches). The bullet shaped insert 12 is provided with a discharge diameter 14 of 1 mm (0.040 inches) and a standoff distance of 25.4 mm to 50.8 mm (one to two inches) may be maintained. It is contemplated that various changes and modifications may be made to the dispenser without departing from the scope of the invention as defined by the following claims.

Claims: A mixer (16) for streamingly dispensing plural component adhesives at elevated pressures and at a desired flow rate, said mixer (16) comprising: a shroud (20) connected to a source of said adhesives at elevated pressures, said shroud (20) having a tapered discharge end (18) and a discharge orifice; a plurality of mix elements (26) contained within said shroud (20); characterised by a dispensing insert (12) contained completely within said tapered shroud discharge end (18), said insert (12) having a reduced diameter discharge hole (14), relative to said shroud discharge orifice, said reduced diameter being sized and said elevated pressure selected to enable streaming of said adhesive at said desired flow rate. A mixer (16) according to claim 1 wherein said discharge hole (14) has a diameter of approximately 1 mm (0.040 inches).

Inventors: BRENNAN THOMAS J, FERGUSON TIMOTHY A, BRENNAN, THOMAS J., FERGUSON, TIMOTHY A.
Applicants: GRACO INC, GRACO INC.
Application year: 1998
Main classification: B05C17
IPC codes: B05C17, B01F5