Spray gun

Aug. 11, 1964

3,144,210

S. LEVY

SPRAY GUN

Filed Sept. 28, 1962

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United States Patent Office _P. _{t d}. ’’’J⁴;²!?

.. Pateated Aug. 11, 19S4

3,144,210 SPRAY GUN

Sidney Levy, 145 W. Cutiibert Blvd., Oaklyn, N.J. Filed Sept. 28,1962, Ser. No. 227,011

Claims. (Cl. 239—415)

The present invention relates in general to a device for mixing fluid streams and in particular to a spray gun in which two different materials which mutually react upon each other are mixed and then dispensed from the spray gun.

Spray guns are in common usage for mixing two different materials so that they can react upon each other and be dispensed as a resultant compound or mixture from the spray gun. In mixing such elements or materials, it is desirable that, in addition to producing an intimate mixture thereof so as to provide the resultant compound, a minimum amount of such materials be retained in the mixing device at the conclusion of the operation thereof. More specifically, and especially when dealing with two highly reactive materials, it is highly desirable that only a minimum amount of one of such materials be retained in the mixing device so as to prevent the continued reaction of the materials which are retained in the mixing device after the operation thereof is discontinued.

In view of the foregoing, it is an object of the present invention to provide a spray gun or mixing device of the character described wherein, upon the discontinuation of the operation thereof, only one of two mutually reactive materials will be retained to a limited extent in the device so as to prevent a continued chemical reaction between the two materials after discontinuance of the operation of the device.

. It is another object of the present invention to provide a spray gun wherein one of the two mutually reactive materials is utilized to purge the compound or mixture resulting from the reaction of the two materials from the spray gun at the termination of the operation thereof so that only a portion of the purging material will remain in the spray gun at the termination of the operation thereof.

It is a still further object of the present invention to provide a highly novel and efficient spray gun of the described type which produces in a minimum amount of time and space a desired chemical reaction between two materials fed into the spray gun wherein material retention and mixing time are kept at a minimum so as to provide greater or maximum control for the resultant chemical reaction.

It is a still further object of the present invention to provide a spray gun of the desired type which may be constructed from a minimum number of parts which operate in a highly efficient manner.

Other and further objects and advantages of the present invention will become readily apparent to those skilled in the art from a consideration of the following specification taken in connection with the appended drawing.

In the drawing which illustrates the best mode presently contemplated for carrying out the invention:

FIGURE 1 is a view in side elevation of a spray gun pursuant to the present invention;

FIGURE 2 is a view of the spray gun taken in the direction of the line 2—2 in FIGURE 1;

FIGURE 3 is an enlarged view of the mixing portion of the spray gun taken on the line 3—3 of FIGURE 1;

FIGURE 4 is a sectional view taken on the line 4—4 of FIGURE 3;

FIGURE 5 is a plan view of a material feed disc, on an enlarged scale, utilized in the spray assembly of the present invention;

FIGURE 6 is a sectional view taken on the line 6—6 of FIGURE 5;

FIGURE 7 is a plan view showing the surface opposite the surface shown in FIGURE 5; and

FIGURE 8 is a fragmentary sectional view taken on the line 8—8 of FIGURE 6.

Referring now to the drawing in detail, FIGURES 1 and 2 illustrate a spray gun 10 which is provided with a spray assembly 12 pursuant to the present invention. 10 The spray gun 10 is provided with a barrel 14 and with a hand grip 16 of conventional construction. The barrel 14 mounts a control member or needle 18 which is biased to the projected position thereof illustrated in FIGURE 1 by means of a suitable spring not illustrated 15 which is provided in the spring housing 20 provided on the barrel 14. The control member 18 is operated to the retracted position thereof by means of a lever or trigger 22 which is pivotally mounted on the barrel 14 as at 24. The spray assembly 12 is mounted on the end of 20 the barrel 14 opposite the end thereof which is provided with the hand grip 16.

As best shown in FIGURES 3 and 4, the spray assembly 12 comprises a body member 26 which is bored at the bottom thereof so as to provide the twin bores 25 28 and 30 which extend only partially into· the body 26. The bores 28 and 30 are adapted to receive the nipples or fittings 32 and 34 which are in fluid flow communication with the material supply conduits 36 and 38 respectively as best shown in FIGURES 1 and 2. The body 30 member 26 is provided also with bores 40 and 42 which extend partly through the body member 26 from the end thereof opposite the end which is provided with the bores 28 and 30. The bores 40 and 42 are disposed eccentrically of the bores 28 and 30, as will be readily apparent 35 from FIGURES 3 and 4 and are in fluid flow communication with the latter bores by means of the entry ports 44 and 46 respectively by means of which fluid or other material is free to flow from the bores 28 and 30 respectively into the bores 40 and 42 respectively. Each 40 of the bores 40 and 42 is provided with a check valve which is constituted by a valve ball 48 which is normally biased by means of a compression spring 50 into a valve seat 52 defined in the adjacent end of the fluid entry or feed bore 44 or 46 as the case may be. The 45 end of each spring 50 opposite the associated valve ball 48 abuts a screw cap 54 which is threaded into the body member 26. From the foregoing, it will be readily apparent that the spring 50 biases the associated ball 48 so as to close the associated fluid feed or entry bore 44 50 or 46 as the case may be.

Extending transversely of the previously described bores and disposed above the bores 28 and 30, as seen from FIGURE 3, provision is made for a bore 56 which extends completely through the body 26. It will be understood 55 that the bores 40 and 42 are in peripheral fluid flow communication with the bore 56 as shown at 58, which indicates where each bore 40-42 opens into bore 56.

At one end thereof, the bore 56 is enlarged as at 60. The enlarged portion 60 defines a seat which receives a 60 flange portion 62 provided on a guide cone 64. The guide cone 64 extends into the bore 56 and with the flange 62 thereof seated in the seat 60, the guide cone is secured in position in the body member 26 by means of the screws 66. At the inner end thereof disposed with65 in the bore 56, the guide cone is provided with a tapered head 68 and at the other end thereof the guide cone is provided with a packing nut 70 which is threadedly engaged therein. A fluid type packing member 72 preferably formed of Teflon or other similar material is provided 70 in the cone 64 upwardly of and in butting relation with Ihe packing nut 70. The guide cone, the packing nut and the packing member 72 are provided with respective bores

3,144,210 which constitute a passageway or slideway 74 in which the previously mentioned control member or needle 18 is mounted for axial reciprocation as indicated by the arrows 76.

At the side thereof opposite the seat 60, the body member 26 is provided, about the bore 56, with a threaded neck 78. A retaining cap 80 is threaded on to the neck 78 and engages the flange portion 82 of a spray tip 84. The tip is provided with an axial recess 86 in which there is housed a preferably carbide insert 88. A spacer 90 is disposed in the bore 55 below the insert 88 and in abutment with the latter. Pursuant to a highly novel feature of the present invention, a jet forming disc 92 is disposed between the spacer 90 and the guide cone 64 within the bore 56. It will be noted that the disc 92, the spacer 90 and the insert 88 are suitably bored or apertured so as to provide portions or extensions of the previously mentioned slideway or passageway 74 for the control needle 18. Consequently, it will be understood that the passageway 74 extends through the packing nut 70, the packing member 72, the guide cone 64, the jet forming disc 92, the spacer 90 and the insert 88 so as to form one continuous passageway for the needle 18, which continuous passageway is described by the reference numeral 74.

As previously mentioned, the jet forming disc 92 forms an important part of the present invention. Referring now specifically to FIGURES 5 through 8, it will be noted that the jet forming disc 92 is constituted by a body portion 94 which is provided on one surface 98 thereof with a collar 96. At its free end surface, the collar 96 is provided with a step portion ICO which in turn is provided at its free end surface with open slots 102. The collar and step portions are centrally apertured as at 104 and it will be noted that the open slots 102 extend from the aperture 104 laterally through the step 100. At the opposing surface 106, the disc is provided with an inwardly tapered recess which is complementary to the tapered head 68 of the guide cone 64. At the narrow end 110 of the recess, the latter is in fluid flow communication with the aperture 104. The recess 108 is provided also with open slots 112 which are open at both ends thereof and which extend to the aperture 104.

With the spray assembly 12 in assembled relation, as best shown in FIGURE 4, it will be noted that an annular chamber 114 is defined within the bore 56 between the surface 106 of the disc 92 and the tapered surface at the tapered head 68 of the guide cone 64, the latter projecting into the recess 108. Furthermore, it will be noted that the valve bore 40 is in fluid flow communication with the annular chamber 114, bore 40 opening as at 58 into bore 56 in which the chamber 114 is defined, the fluid flow from bore 40 into chamber 114 being indicated by the arrow 116. A second annular chamber 118 is defined between the opposing surface 98 of the disc 92 and the adjacent surface of the spacer 90. Said annular chamber 118 is in fluid flow communication with the valve bore 42 which opens as at 58 into bore 56 in which the chamber 118 is defined, the fluid flow from bore 56 into chamber 118 being indicated by the arrow 120. Furthermore, it will be understood that with the cone inserted into the recess 108, as illustrated, the open slots 112 of the recess 108 are closed along their longitudinal extent so as to define passageways which extend between the annular chamber 114 and the previously described passageway or slideway 74. Similarly, it will be noted that the under or adjacent surface of the spacer member 90 closes the longitudinal open sides of the slots 102 so as to define enclosed passageways between the chamber 118 and the passageway or slideway 74.

The control member or needle 18 which is reciprocable in the passageway 74 is provided with a sleeve 122 which is preferably formed of Teflon or other similar material and serves as a seal between the needle and the surfaces of the bore. Furthermore, it will be noted that the bore or slideway in which the needle is reciprocable terminates in a narrowed opening or aperture in the insert 88 so as to define a spray nozzle. With the needle 18 in the fully retracted position thereof, as shown in FIGURE 4, it will be noted that the slots 112 as well as the slots 102, which constitute ports for cuid communication between the respective chambers 114 and 118 and the passageway in which needle 18 operates are all clear so as to be unobstructed and to permit fluid flow communication between the associated annular chambers and the passageway 74. Furthermore, it will be noted that when the needle is in its intermediate position as indicated by reference numeral 126, the ports 112 are closed at the outlet thereof into the passageway 74 while the ports 102 are still open for outlet into the passageway. However, it will be apparent that when the needle continues to advance in the direction of the arrow 130 for example to the position thereof indicated at 128, the ports 102 are also closed so as to prevent passage of fluid into the slideway 74.

In order to operate the spray gun 1®, the conduits 36 and 38 are each connected to suitable supplies of the materials which are to be mixed. For example, assuming now that the spray gun is to eject a polyurethane foam formulation such as for example epoxy or a polyester foam formulation, one of the conduits would be connected to a supply of a prepolymer of toluene diisocyanate and a polyol as one component and a second polyol, for example Freon 11, a catalyst mixture as the second component, these components to be mixed and sprayed in a one to one ratio. It will be understood that the materials are supplied in the conduits under a suitable pressurized condition which is sufficient to drive the materials up through the conduits 36 and 38 against the pressures exerted by the springs 50 and the weight of balls 52 to which the spring pressure is applied. With the lever or trigger 72 retracted so as to retract the needle 18 to its fully retracted position as shown in FIGURE 4, the outlets of the slots 112 and 102 are free of the needle 18 so that a passageway is completed between the annular chambers 114 and 118 and the slideway 74. Consequently, the pressurized materials are now free to flow upwardly through the respective communication ports 44 and 46 and into the associated bores 40 and 42 to supply the materials to the associated chambers 114 and 118 respectively. The materials supplied to chamber 114 now flows through the plurality of slots 112 into the passageway 74 forwardly of the needle 18. However, it will be apparent that by flowing through the narrow or restricted slots 112 the pressurized material is formed into jets which enter the passageway along generally chordal paths as will be apparent from the relationship of the slots 112 to the aperture 104 illustrated in FIGURE 7. Similarly, the materials flowing into the annular chamber 118 and through the slots 102 will for the same reasons form jets which enter the passageway along generally chordal paths. As a result, the chordal jets flowing from each of the annular chambers v.'iil mix in the passageway in front of the free end of the needle 18 and will react in said chamber to form the desired formulation. The fact that each of the materials are formed into jets will greatly hasten the time required for the mixture thereof and for the resultant chemical reaction therebetween. Due to the fact that the materials enter the assembly 12 in a pressurized condition, the resultant mixture will be forced out of the nozzle 124 as indicated by the arrow 132 in a jet spray for application as desired. When the trigger 22 is released, the biased control element or needle 18 will advance in the direction of the arrow 130. When the needle reaches the intermediate position thereof indicated by the reference numeral 126, it will be noted that the needle is now in a position to close off or block passage of the fluid or material which is in chamber 114 from entering the passageway 74 with the result that the sole material which now enters the passageway forwardly of the needle is the material which

3,144,210 is in the chamber 118. Consequently, this material now acts as a purging material so as to eject from the passageway all remnants of the resultant mixture resulting from the reaction of the two materials so that the only material which is now in the passageway forwardly of the needle is the single material coming from the chamber 118. The continued forward movement of the needle for example to the position thereof shown by the reference numeral 128 will block or close up the passageways 102 so as now to cut off the flow of material from the chamber 118 into the passageway 74, the advance of the needle 18 serving to eject through the nozzle 124 most of the purging material. When the needle 18 reaches its fully projected position as shown by reference numeral 128, there remains between the head of the needle and the nozzle 124 only a relatively small remnant of the single material which had been supplied from the chamber 118. Therefore, it will be apparent that during the period when the spray gun is not being used, there is only a relatively small amount of one of the materials remaining in the spray assembly and since the second material has been completely purged from the chamber as well as the mixture or formulation of the two materials, it is impossible for any chemical reaction to occur between the two materials during the time that the spray gun is inoperative.

From the foregoing, it will be readily apparent that I have described and illustrated a highly novel spray gun apparatus which represents the presently preferred embodiment of my invention. It will be apparent that changes and modifications may be made therein without, however, departing from the spirit and scope of the invention as set forth in the appended claims.