GB2145014A - Material spraying apparatus - Google Patents

Abstract

A material spraying apparatus, for spraying of paints and other liquids which is accomplished with relatively low air pressures, and which is easily adaptable for portable units, includes at least a pair of serially mounted air turbines (50), 51 for delivering air under relatively low pressures to a material spraying gun or applicator and means 60, 65-67 for removing heat generated in the operation of the turbines from the air being delivered to the gun. The material to be sprayed and the air delivered from the turbines mixed at the spray gun or applicator and the material is atomized for proper application to the surface to be covered. The apparatus also includes an easily removed material reservoir unit 32 and fluid control means for priming a material pump 35 and drainage means (38, Fig. 11) for ease of draining of the reservoir after usage. <IMAGE>

Description

SPECIFICATION Material spraying apparatus This invention relates generally to material spraying apparatus. More particularly it concerns equipment and systems which include a material supply and an air supply for carrying the material to the article to be covered, and especially to material spraying equipment and systems having a low pressure air flow system, with a positive displacement and material delivery system, and which includes means for controlling the temperature of the air flow; the system particularly eliminating any air holding, pressurizable tank.

The art of spraying paint and other materials is well known. Standard paint or material spraying units include a supply of the material and a supply of air, these both being delivered to a spray gun or applicator from which the air acts as a transporting medium for conveying the material to the article being covered with the material.

Various reservoir systems are available in the art depending upon the particular application desired. For what may be termed small applications, a spray gun is provided with a material retaining cup and air under pressure is introduced into the cup with the material then being forced therefrom into a continuing air spray where the same is atomized and carried to the article being coated.

Another form for providing a supply of the material is a gravity feed situation wherein a material reservoir tank is arranged above the normal level of operation and the material is fed by gravity to the gun where again, the same is atomized by the transmitted air and delivered to the article being covered.

A third method of material supply is to provide a tank or reservoir for material into which air, under pressure, is introduced for forcing the material to the gun or applicator, and yet a fourth method is to provide a reservoir from which the material is mechanically pumped under pressure to the gun.

Standard methods for delivering air to the gun or applicator include a source of high pressure air which is monitored prior to delivery to the gun. The normal mechanism and apparatus for providing this high pressure source of air is through the use of an air compressor and an air storage tank. Such apparatus is perfectly acceptable for what may be termed stationary applications but greatly impedes and provides cumbersome systems when a portable unit is desired.

There are other methods for transmitting material to an article to be covered, and these include electrostatic methods wherein the material particles are electrically charged with the article to be covered being oppositely charged. Minimal air blowing techniques may be incorporated into such an electrostatic system or the system may simply rely upon the electrical attraction to draw the covering particles on to the article.

Other devices that are known in the art include what are defined as airless spray guns.

Prior specifications known to the applicant include U.S. Patents Nos. 4,208,013, Coleman et al; 3,940,065, Ware et al; 3,347,469, Ross et al; and, 3,551,178, Chmelar. These latter two patents are related to electrostatic applications of materials, but they do not include what may be classified as a turbine driven, air propellant, while the Ware patent is a positive displacement unit and the Coleman patent discloses a turbine unit.

An object of the present invention is to provide a material spraying system and apparatus therefore which includes structure for positively providing a supply of material to be sprayed to a spray gun or other applicator and to simultaneously supply air to the spray gun or applicator for atomising the material and delivering of the same to the article to be covered; the air being supplied at a relatively low pressure and at a controlled temperature.

A further object of the invention is to provide a material spraying system and the apparatus therefore which includes a material supply system having a reservoir and a positive pumping structure and which includes means for providing air for the atomization of the material and the transmission thereof to the article to be covered wherein the air supply system includes at least a pair of serially connected turbine members.

Another object of the invention is to provide a material spraying system and apparatus which includes a supply of material being positively delivered to a spray gun or applicator and an air system for supplying air to the spray gun or applicator wherein the air supply system includes at least a pair of serially connected turbine members and a heat exchanging unit such that the air delivered from the turbines passes through the heat exchanger unit and is thereby delivered to the spray gun or applicator at a predetermined and limited elevated temperature above ambient temperature.

Another object of the invention is to provide a material spray system and the apparatus therefore which includes a material reservoir and a positive pump mechanism for delivering material from the reservoir to a spray gun or other applicator, which further includes means for easily priming the pumping mechanism and for, alternatively, draining the material reservoir.

A still further object of the invention is to provide a portable spraying system and the apparatus therefore which includes a material reservoir, a positive pumping mechanism for delivering material from the reservoir to a spray gun or applicator, and an air supply means which includes at least a pair of serially connected turbine members with the delivery therefrom being directed through a heat exchange unit for ultimate delivery to the spray gun or applicator, all of which elements are mounted on a portable unit.

Yet a further object of the invention is to provide a material spray system and the apparatus therefore which includes an electrical system to transform the power received at the apparatus to a proper electrical power operating level.

According to the present invention I provide a spraying unit for the application of materials such as paints or the like to an article, said unit including:.

a) an applicator member arranged and constructed to receive material to be sprayed and air for atomizing the material and conveying the same to the article to be covered; b) means for providing a supply of material; c) means for delivering material from said supply means to said applicator; d) air supply means for supplying air under pressure to said applicator; and, e) means for controlling the temperature of the air being delivered to said applicator.

The device of the invention eliminates the compressor-pressure tank storage concept and rather provides a sufficient stream of air at a minimally increased pressure and at sufficient rate to accomplish the spraying. It further includes a means for maintaining the pressure of the delivered air at a temperature of from five to twenty degrees above ambient temperature. Delivery may be accomplished through the utilization of serially connected turbines and the air temperature is controlled by passing the air supplied by the turbines through a heat exchanger, prior to delivery to the gun.

The material supply in the device can include a reservoir and a positive displacement pump mechanism for delivering the material to the spray gun. The spray gun may be of a normal design, and the air atomizes the material to be sprayed for delivery from the gun on to the article.

In the device, the air compression and storage stage is eliminated and therefore, the unit is particularly adaptable to portability.

Reference is now made to the accompanying drawings, in which: Figure 1 is a perspective view of the spraying unit embodying the concepts of the invention; Figure 2 is a top plan view thereof; Figure 3 is an elevation taken from one side of the unit and illustrating the material supply reservoir in a removed or removable position in dotted lines; Figure 4 is an elevation taken from the side opposite that of Figure 3; Figure 5 is a front elevation thereof; Figure 6 is a rear elevation thereof; Figure 7 is a horizontal section taken substantially along line 7-7 of Figure 4; Figure 8 is a horizontal section taken sub stantialiy along line 8-8 of Figure 4; Figure 9 is a vertical section taken substantially along line 9-9 of Figure 2; Figure 10 is a vertical section taken substantially along line 10-10 of Figure 8;; Figure 11 is a vertical section taken substantially along line 11-11 of Figure 8; Figure 1 2 is a schematic illustration of the material delivery path and the air delivery path to provide the material applicator with both material and air; and, Figure 1 3 is an electrical schematic of the unit.

The spray unit 10 comprises cabinetry including a bottom 11, sides 12, 13, and a front 14, and rear 15. A top 16 is, as shown in the drawings, of a stepped configuration.

The particular shape of this upper surface 1 6 is designed for esthetic qualities and functional qualities.

The various elements of the cabinetry assist in the operation of the unit. For example, the bottom surface 11 is provided with a frontal rest 20, and is also provided at the rear thereof, with a pair of wheels 21 a, 21 b mounted on a common axle 21. Bracket means 22 are provided to hold the axle onto the bottom surface 11 of the cabinet.

Rear surface 1 5 provides a plurality of air vents 22 for the admission of air into the interior of the cabinetry. Frontal surface 14 consists of a screen or grid material for the passage of air and this grid material is designated 23.

Side 1 3 provides a plurality of air inlets 24, and a specific air outlet 25 which outlet is provided with a grid system 25a, or the like.

The opposite side of the cabinet 12, also provides a plurality of inlet air sections or vents 25, and also provides a hinged and latchable door 26 thereon, which door is arranged to allow access to the material dispensing pump.

Arranged and attached to the respective sides 12, 1 3 of the unit 10 is a handle designated generally 27. As illustrated, this handle provides a pair of extending arms which engage the respective sides 12, 1 3 of the unit.

Top 16, as previously mentioned, includes a stepped construction which consists of a lower flat section 16a, a rearwardly and upwardly slanted control panel section 16b, and an upper flat section 16c.

Arranged on the slanted control section 1 6b, are a set of switches, designated in their entirety 30, and an auxillary air valve designated 31. This air valve 31 is connected to the internal air flow system and allows the use of two applicators or spray guns, at the user's option.

The upper flat surface 1 sic is provided with a rectangular aperture 16dtherein such that a material reservoir 32, may be inserted therein.

In the form shown, this reservoir 32 includes a tank section 32a and a cover section 32b.

As particularly illustrated in Figure 3, this reservoir unit 32 is completely removable from the aforementioned aperture 16 d, and such removability is obtained by providing a connecting product line 32cof an additional coiled dimension or length which will permit insertion and removal of the reservoir through the aforementioned aperture 1 6 d of the top 16. This type of arrangement then allows for the complete removal of the reservoir unit for cleaning or the like. Delivery line 32e extends from the bottom reservoir to the positive pump/motor.

A pump/motor combination is provided for positive delivery of the product to the applicator 41. In this instance, the pump and motor combination is designated 35, and a unique priming and draining mechanism is associated with the pump/motor 35, and is arranged behind the aforementioned door 26 on side 1 2. As illustrated, the material is delivered through line 32e to a priming and power drain block 36, which is associated with the pumping section of the pump/motor 35, and a petcock 37 is arranged thereon with an outlet conduit 38 extending therefrom. The concept of this arrangement is to, when priming the unit, open the petcock 37 and allow fluid flow until the fluid is flowing through outlet line 38. At this time it is known that the pump is properly primed and will properly deliver material without any possibility of air inclusions and the like.The other aspect of this petcock outlet situation is for draining of the reservoir 32. As should be obvious, material is delivered from the pump through an outlet line 40 which extends to the applicator such as spray gun 41. When it is desired to drain the reservoir 32, the trigger mechanism 41 a normally provided on the gun 41, will remain in closed position and the petcock 37 will be opened. This condition will then cause, upon actuation of pump/motor 35, the material to flow through the petcock 37 and out of the priming and draining line 38.

To this point, then, it should be obvious that the material being utilized may be supplied in bulk by filling reservoir 32 and thereafter, the material is positively delivered under pressure to the applicator gun 41. As stated above, it is possible to, when utilizing this unit for relatively small jobs, use what is known as a cup container. With a cup container, a paint or material container cup is screwed directly onto the applicator 41, and the air passing through the applicator or gun will, through a venturi action, draw the material from the cup source. When such a cup source is utilized, then it is obvious that the pump 35 is not actuated, and no material will normally be provided to the reservoir 32.

The method for introducing air under pressure includes means for producing and delivering this air under pressure to the applicator 41 at a predetermined elevated temperature.

This elevated temperature will be from eight to twenty degrees centigrade over ambient temperature, and I have particularly designed this unit for air delivery at relatively low pressures. Low pressure, in this situation, is defined to be in the range of four to twenty psi over atmospheric pressure. I have found that this minimally elevated temperature provides an optimum application temperature, and the air pressure is such that it is sufficient to properly atomize material being delivered to the gun. A combination of this temperature control and a low pressure situation results in optimum spraying techniques, and, as previously stated, eliminates several disadvantages of compressor units.

A compressor unit often results in surges of air being delivered to the applicator, and often also results in an accumulation of water in the compressed air, and therefore, a drainage system must be provided. With my low-pressure system, the unit is in continuous operation during spraying, and the low pressure does not permit the formation of water in the delivered air.

As best illustrated in Figures 9, 10, and 11, a pair of centrifugal air pumps or fans designated 50, 51 are mounted on the base or bottom cabinet section 11, through support posts 54 and each of these centrifugal pumps 50, 51 is powered by its respective motor 52, 53 which overlies the pump or fan. The intake for these fans 50, 51 is from the bottom thereof, and the outlets 55, 56 are arranged on the sides thereof. These units are serially joined and as particularly illustrated in Figure 10, outlet 55 of pump 50 is directed into an enlarged deflector, manifold unit 57, which then in turn is connected to pump 51 at the lower inlet surface thereof. The aspect of this deflector, manifold 57 is to provide a method wherein the air is delivered to the second pump at delivery temperature from pump 50, but the velocity thereof has been reduced due to the deflector size and interior baffling.This will allow for a more efficient serial flow of air between the two pumps. After the air has passed through the second stage pump 51, it is delivered therefrom through outlet 58.

A most important treatment of the air occurs at this time. A heat exchanger designated in its entirety 60, is provided adjacent the front grill cabinet member 1 4. The air delivered from the second stage pump 51, which passes through the conduit 58, is directed to a vertically arranged manifold 61. A plurality of transversely extending conduits 62 are provided to receive air from manifold 61 and these conduits 62 extend to a collector manifold 63 spaced from the inlet manifold 61.

For proper heat transfer, a plurality of fin members 64, enshrouding the cross-connecting conduits 62 are provided and cooling air to pass through this heat exchange unit 60 is provided by a cooling fan designated generally 65 which consists of a fan blade unit 66.

and a motor 67. This cooling fan unit 65 is mounted to bracket 68 to the bottom cabinet section 11.

It should be obvious to anyone skilled in the art that an increase in pressure of air will result in an increase in temperature, and the cooling effect of the heat exchanger 60, and the cooling fan 65, reduces the temperature of the air which is ultimately delivered to the applicator 41. Arranged along this air flow line 70 is an air regulator 71, such that final delivery pressure to the gun may be obtained.

Air flow through the system should be obvious from the description of the system to this point. Obviously, air is taken in through the first fan unit 50, and is delivered therefrom by the feed manifold 57 to entrance into the second serial air fan 51. Air then is delivered from the second stage fan through conduit 58 and into the heat exchanger 60.

After exiting from the heat exchanger 60, the air passes through a regulator 71, for ultimate delivery to the applicator gun 41.

The interaction of the delivered material and the delivered air is illustrated in the schematic of Figure 12.

As mentioned above, it is necessary to run the fans 50, 51 at a proper voltage. To accomplish this, a step-up transformer designated 75 is provided. This step-up transformer is approximately in the ratio of 1.217:1.

These fans 50, 51 are normally designed to run at 140 volts and therefore, this step-up transformer is necessary for proper operation.

As illustrated in Figure 7, a motor 76 and fan construction 77 is provided to provide a cooling unit 78, to normally blow cooling air across the transformer 75 to maintain the same in a cool condition for proper operation thereof.

The schematic of Figure 1 2 has substantially been described to this point. The electrical schematic of Figure 1 3 is relatively simple, and consists of the aforementioned switches 30, in which a main switch 80 is provided, a pump control switch 81 is provided, and a fan control and air blower control switch 82 is provided. When the main switch 80 is shifted to its energizing position, it should be obvious that the pump/motor 35 may be utilized to completely drain the reservoir 32 without energizing any of the remaining portions of the unit. This arrangement also allows for priming of the pump/motor 35 mechanism prior to initiation of the spraying operation.Shifting of switch 82 will result in the heat exchanger fan 65 being energized as weil as the transformer cooling fan 78 being energized, and similarly, the step-up transformer is energized to ensure the proper voltage to the two centrifugal motors and fans 50, 51, 52, and 53.

Upon completion of all these switching functions, the material and air is provided at the gun with proper operating characteristics for each of the same. Actuation of the trigger 41 a will then cause atomization of the material and spraying thereof due to the air being delivered to the gun. As previously stated, if a cup-type gun is being utilized, then no product will be delivered by pump/motor 35 and switch 81 will not be energized. The material will be drawn from the cup through the pressure of the air being delivered to the gun through the air line 70.

The spraying results are the same whether a cup or reservoir source of material supply is provided.

The advantages of my invention have previously been stated; but one important aspect of my invention is that, due to the no-surge air delivery situation of my unit as compared to a compressor-type operation, there will be less spurting of material onto the article to be covered. All persons that are acquainted with spray painting realize that such spurting is totally unwanted, and normally results in wiping the article down, and redoing the entire job. With my continual supply at a relatively low pressure, such spurting will not exist.

It should therefore be obvious to anyone skilled in the art that I have provided a new and unique material spraying unit which is particularly designed for portability, and which will positively provide material to be sprayed to the applicator, and which will provide air for the atomization and carrying of the material to be sprayed to the article at a controlled, relatively low pressure. It should also be obvious that I have provided a unit which provides a reservoir for the material which reservoir may be easily removed from the unit without disconnecting any portions thereof.

Also, I have provided a secondary valving system which of essence, must consist of the aforementioned outlet valve 31, which is interially connected to the output manifold of the heat exchanger. This particular connection has not been shown nor discussed in this description, but the valve 31, provides an outlet for such second gun, and it should be obvious that an inter-connecting air flow conduit must be afforded to the outlet manifold of the heat exchanger.

Claims (20)

1. A spraying unit for the application of materials such as paints or the like to an article, said unit including: a) an applicator member arranged and constructed to receive material to be sprayed and air for atomizing the material and conveying the same to the article to be covered; b) means for providing a supply of material; c) means for delivering material from said supply means to said applicator; d) air supply means for supplying air under pressure to said applicator; and, e) means for controlling the temperature of the air being delivered to said applicator.

2. A spraying unit according to Claim 1 wherein said means for providing a supply of material includes a material reservoir.

3. A spraying unit according to Claim 2 with flexible connector means provided between said reservoir and said material delivery means to permit shifting of and relative positioning thereof.

4. A spraying unit according to any of Claims 1 to 3 wherein said material delivery means includes a pump.

5. A spraying unit according to Claim 4 with positionable directing means associated with said pump whereby material may be directed from said pump to said applicator in a first position and material may be directed to a remote location in a second position.

6. A spraying unit according to Claim 4 or 5 with self priming means associated with said pump.

7. A spraying unit according to any of Claims 1 to 6 in which said air supply means supplies air to said applicator in the range of 5 to 20 psi.

8. A spraying unit according to any of Claims 1 to 7 in which said air supply means includes: a) air pumping turbine means; and b) means for providing rotative power to said turbine means.

9. A spraying unit according to Claim 8 in which said turbine means includes at least a pair of serially connected turbines.

10. A spraying unit according to Claim 9 having air diffusion and deflector means arranged between such serially connected turbines to receive exhaust air from one of said turbines and direct the same in diffused manner to the next succeeding turbine.

11. A spraying unit according to any of Claims 1 to 10 in which said temperature controlling means includes heat exchanger means.

1 2. A spraying unit according to Claim 11, said heat exchanger means including: a) a first manifold to receive air from said air supply means; b) a second manifold spaced from said first manifold and arranged and constructed to deliver air therefrom to said applicator member; c) air flow means between said first and second manifold; and d) means for delivering a cooling medium across said air flow means for cooling the air passing between said first and second manifold.

1 3. A spraying unit according to Claim 12, said cooling medium including air.

14. A spraying unit according to any of Claims 11 to 1 3 and said temperature controlling means maintaining the temperature of the air delivered from said second manifold in a range of 5 to 20 degress above ambient.

1 5. A spraying unit according to any of Claims 1 to 14 provided with electrical control circuitry including a transformer receiving electrical energy from a source and delivering the same to rotative power providing means for operation thereof at a desired operating electrical level.

1 6. A spraying unit according to Claim 1 5 having upper level control means to control the maximum voltage level delivered to said rotative power providing means.

1 7. A spraying unit according to Claim 1 6 in which said upper level control means limits the delivered voltage to 140 volts.

18. A spraying unit according to any of Claims 1 to 1 7 and a mounting frame on which said supply means, said material delivery means, said air supply means and said temperature controlling means is mounted.

1 9. A spraying unit according to Claim 18 in which said frame is such that the unit is easily portable.

20. A spraying unit substantially as herein described with reference to the accompanying drawings.