US2045164A

US2045164A - Spray system

Info

Publication number: US2045164A
Application number: US632545A
Authority: US
Inventors: Richards Harlan
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-09-10
Filing date: 1932-09-10
Publication date: 1936-06-23
Anticipated expiration: 1953-06-23

Description

June 23, 1936. H, RIC ARDS 2,045,164

SPRAY SYSTEM Filed Sept. 10, 1932 2 Sheets-Sheet l June H RICHARDS SPRAY SYSTEM Filed Sept. 10, 1932 2 Sheets-Sheet 2 Patented June 23, 1936 UNITED STATES PATENT OFFICE SPRAY SYSTEM Harlan Richards, Chicago, Ill.

Application September 10, 1932, Serial No. 632,545

13 Claims. (Cl. 299-46) My invention relates to methods of and means for spraying coating materials.

There are many different types of coating materials applied to surfaces by means of spray 5 equipment. Ordinary spray painting is most illustrative and for convenience my invention will be described as applied to this important use. It should be understood, however, that the term paint is employed in a broad sense to include 10 all of the usual liquid materials having the appearance and characteristic of paint, as for example the true oil paints, stains, lacquers, enamels, and the like.

Spraying painting is usually accomplished by 5 atomizing the paint by a stream of compressed air, that is breaking the material up into minute particles and directing a stream of mixed particles and air against the surface to be painted by means of a suitable type valve controlled nozzle, 20 usually referred to as a gun. The atomizing takes place in accordance with the usual systems employed either at the nozzle or in a. tank located some distance from the nozzle or gun. In the first method, two lines are employed, one for the air and the other for the paint. In the second method, only a single line or hose is usedbetween the point of atomization and the gun.

The so-called two-line systems are also roughly divided into two classes which may be re- 30 ferred to as the high and low pressure systems,

the names being derived from the proportionate amount of air and pressure thereof employed. There are certain advantages of theoretical and practical significance in both the low and high 35 pressure systems and, of course, concomitant disadvantages. In each of the two-line systems, the

paint is atomized at the gun by suitable means and air, either immediately before they leave the gun or as they leave the nozzle of the gun. Both of these systems employ a paint tank and utilize air pressure above the paint contained in the tank to force the paint from the tank through the paint line to the nozzle.

Among the principal disadvantages of the low pressure two-line system is that the paint tank must be supported at a point not greatly below the level at which the painting takes place, othr erwise the pressure will not be suflicient to lift the paint to the elevated position. There are, however, some advantages in the use of the low pressure system under certain conditions. The high pressure two-line system in general is preferred I to the low pressure system, but under some conditions it also has certain disadvantages.

The single line system, if satisfactorily operated, presents very many advantages over the two-line system. Its greatest value, of course, is in the fact that there is only one line to maintain and for the operator to carry with him during a painting operation. As the single line system has been employed heretofore, however, it has been impossible to obtain a sufilciently uniform coating for all purposes. Possibly if it were practical to operate the spray gun continuously, the difficulties encountered in this respect could be avoided, but, in practical operation up to the present time, all single line spray systems with which I am familiar have shown the same lack of uniformity.

The principal object of my invention is the provision of an improved spray painting system.

Another object is to utilize all of the advantages inherent in the various systems and to avoid the disadvantages usually found in the various systems.

Another object is the provision of improved means for delivering the paint at a controlled but uniform rate to the point of atomization.

Another object is the provision of improved means for atomizing the paint which will permit satisfactory performance with only a single hose line.

Another object is the provision of an improved single line paint spray system.

Other objects and features of the invention will be apparent from a consideration of the following detailed description taken with the accompanying drawings, wherein Fig. 1 is an elevational view showing apparatus forming a part of my improved system;

Fig. 2 is a plan view thereof;

Fig. 3 is a plan sectional view taken on the line 3-3 of Fig. 1, illustrating features of my improved atomizing means; 4

Fig. 4 is an elevational view showing one type of pump apparatus which may be used for delivering the paint in accordance with my system, one end plate of the pump being removed to show the interior structure thereof;

Fig. 5 is a plan sectional view taken on the line 5-5 of Fig. 1, showing details of a pressure control valve;

Fig. 6 is a sectional view, partly in elevation, taken on the line 6-6 of Fig. 2; and

Fig. '7 is a plan view showing certain modifications in the apparatus.

In accordance with the general features of the invention, I support the paint in an open container of any suitable type and by means of a 5 positive acting pump deliver the paint through a suitable line and in proper and controlled amounts to the atomizing apparatus. This feature of the invention may be employed with either a two-line or single-line system, as will be pointed out more fully hereinafter, and in either case this feature alone is efiective to avoid many of the difliculties heretofore encountered. This positive delivery of the paint is controlled, however, so that there can under no circumstances be a flooding of the vaporizing apparatus, which would occur if too large an amount of paint were delivered during a rest period. The features of this control will be explained in detail. I also provide improved means for atomizing the paint in such a way as to make it possible to employ a single line connection of any required length between the atomizer and the gun, thus making it possible to utilize all of the advantages of the single line system while avoiding all of its disadvantages.

The apparatus shown in Figs. 1 to 6, inclusive, is illustrative of an embodiment of the invention with which I have produced very excellent results. A base l0 supports a suitable motor I I, preferably an electric motor of relatively small horsepower. The motor shaft is provided with a sheave I2 for driving a belt I3, the belt driving a sheave or pulley l4 secured to a shaft l6 of a relatively small pump I1. This pump may be of any suitable type to deliver a positive and uniform supply of paint. The pump actually shown, however, will be referred to more in detail hereinafter.

The pump withdraws paint from a supply pipe l8 to which paint is delivered by suitable couplings, as shown, through a flexible hose connection IS. The opposite or open end of the hose provided with a suitable screen (not shown), if necessary, is inserted in an open paint container 2| supported in any suitable and convenient position with respect to the remaining portion of the apparatus.

The paint is delivered from the pump through a pipe line 22 and thence through a suitable connection to a pipe 23 which in the present case is shown connected to an atomizer indicated generally by the reference character 24. An ordinary type of lift check valve 26 is inserted in the pipe 23 and has a function whichwill be explained more fully as the description proceeds.

The pipe 22 is also connected to a by-pass valve 27 adapted to be regulated in a suitable manner to relieve itself into the pipe [8 when the pressure of paint is raised above a predetermined amount. A gauge 28 is connected to show at all times the pressure in the pipe 22 and the portion of the bypass valve directly connected thereto.

The pump !l is preferably of a rotary type so as to deliver a constant supply of paint during the entire time that it is operating. The pump shown in Fig. 4 is a standard type of commercial rotary pump in which the shaft I6 is provided with a cup-shaped gear 29 and a second gear 3| carried on a shaft 32 journaled in the outer casing is set eccentrically to the first mentioned gear 29, the teeth of the two gears meshing and by reason of their offset relationship having a differential sliding action with respect to each other. Rotation is in the direction indicated by the arrow in Fig. 4. An intake port 33 provided in the body of the pump is connected with the pipe I8 and delivers paint to the space between the gears as this space gradually increases. An exhaust port 34 similarly formed in the casing and connected to the pipe 22 communicates with the space between the gears at a point where this space is gradually diminished. The result is a suction action on the intake port 33 to withdraw the paint from the open container and a pressure action on the port 34 to force the withdrawn paint through the port and into the pipe 22. The action is continuous and uniform.

The pressure relief and control valve which I employ is of the diaphragm type and is shown in considerable detail in Figs. and 6. The valve includes a valve body 36, a diaphragm 37, and a spring housing 38 in which a diaphragm spring 39 is disposed, the diaphragm housing being secured to the valve body so as to clamp the diaphragm against an annular portion of such body. The valve body is cupped to provide a pressure space 4| with which the pipe 22 communicates through a port 42. A pipe 43 leading to the pressure gauge is threaded into the valve body and also communicates with the pressure space 4| through a suitable port arrangement 44. The pressure relief valve per se includes a removable valve seat 46 and a valve 47. This valve forms part of a follower 48 disposed in a cup-shaped opening 49. The valve has a projection engaging against a diaphragm washer 5| so that the pressure of the spring 39 against the diaphragm tends to hold the valve 41 in a closed position. When the pressure is increased beyond that predetermined by the pressure of the spring, however, the dia phragm is forced away from the valve 41 to permit it to open. A spring 52 bearing against the valve follower 4B is then suflicient to raise the valve 4'! from its seat against the pressure of the paint and permit some of the paint to pass through the valve into the cup-shaped opening 49. The pipe i8 is threaded through a suitable coupling into the valve body and communicates with a port 53 leading into the cup-shaped opening 49. The spring 39 has a follower 54 against which the end of the adjusting screw 56 bears, and the adjusting screw being threaded in the spring housing can be turned to provide for any suitable compression of the spring 39 within the limits of the design..

I prefer to operate my system as a single line system, and Figs. 1 to 3, inclusive, illustrate an improved type of atomizer adapted to be used in combination with the portion of the system already described. This atomizer previously referred to by the numeral 24 is supported from the base In by a suitable pedestal 58. It comprises in its preferred form a casting or forging having a general shape of a T, as shown in the section of Fig. 3. A central atomizing chamber 59 is provided and the paint is delivered to this chamber through a nozzle or nipple 6| which projects from a plug-like coupling member 62 to which the pipe 23 is also connected. A relatively narrow port 63 delivers the paint in a fine stream to the tip of the nozzle. Air under suitable pressure and at suitable velocity is delivered to the atomizing chamber through a flexible air line 64, the line being connected to the atomizing chamher by means of a suitable plug coupling 66. It will be understood that any of the usual means for compressing and maintaining a supply of air for the purpose may be employed, and accordingly I have not shown any form of compressor for use with the present invention. After being atomized in the chamber, the mixture of air and paint is delivered through a flexible pipe line 67 to a spray gun 68 which the operator uses in the actual application of the paint. A coupling is provided for making this connection and is .disposed in line with the incoming air supply and at right angles to the direction of movement of paint through the nozzle 61. This coupling is provided with a cup-like open space H which in some respects forms a continuation of the atomizing chamber. The drawings show a fourth opening to the atomizing chamber provided with a stop plug 12. This opening has no utility except to simplify manufacture and maintenance of the atomizer.

In the operation of the system, the actual work of the operator is carried on in substantially the same way as if he were operating an ordinary single line system with, of course, the improved operation which I have made possible. The apparatus is employed and adjusted as follows: The base It carrying the apparatus is set in any convenient and suitable location where power and a source of air is available. If it is operated in a regularly established shop, the proprietor of the shop would, of course, be provided with a suitable air compressor to which the line 64 would be connected. Much of this work is done in locations where there is a regularly established compressed air system and in this case the air line would be connected to a convenient outlet. Paint to be employed is placed in an open container such as 2| and the open end of the flexible hose line [9 inserted in the container beneath the surface of the paint. The usual switch is then operated to supply electrical power to the motor to drive the pump. This causes the paint to be withdrawn from the open container and delivered under pressure to the pipe 22 and thence through the connections described to the relief and control valve 21 and to the gauge 28. Experience will tell the operator the most desirable pressure to be employed in the paint line, it being understood that this pressure must bear a relationship to the air pressure. Usual gauges are, of course, provided to show the air pressure at all times. When the pump has been started and allowed to run for .a short time in order to completely fill the paint line, the pressure is observed on the gauge 28 and the pressure of spring 39 then adjusted until the pressure is suitable. Assume at this time that the control valve of the gun 68 is closed and there is no movement of any kind through the line 61. The paint will then be delivered to the chamber H through pipe 22 and port 42. Due to the fact that no paint is being delivered out of the atomizer nozzle 6|, for reasons which will be pointed out clearly, the pressure of paint in'the chamber U will move the diaphragm against the pressure of spring 39 and allow the valve 41 to open. Paint will then flow past the valve into the cup-like opening 49 and thence through port 53 back into the paint pump intake pipe l8, again to be delivered to the intake port of the pump. I have found that the pressure in the pipe line, as shown by the gauge, is the same at all times during operation, whether the gun is being operated or not. When the paint is allowed to flow to the atomizer, there will be less paint by-passed, but the pressure will remain constant. When the valve operated by the relief mechanism provided on the gun 68 is opened, air pressure in the chamber 59 of the atomizer will be decreased to some extent and also the air present will move at a relatively high velocity past the nozzle 6| producing a condition facilitating the delivery of paint through the port or channel 63. This paint, of course, is positively delivered at such time in regular amounts determined by the pressure control. As fast as it is defivered to the atomizing chamber, this paint is atomized by the stream of air rushing past and combining with it, and it remains in an atomized condition until it passes the spray nozzle of the gun 58 andimpinges on the surface to be painted. Assume now that the gun is operated to close its control valve. The air pressure against the paint in the port 63 of the nozzle 61 is increased and the pressure of the paint is not suflicient to deliver it against pressure. Should there be any tendency for "the air pressure to force the paint back through the paint line, the lift check valve 26 will come into operation and prevent such a possibility. At this time,.alsc, as previously set forth, a greater amount of paint will be by-passed through the valve 21 and this permits the motor and pump to be operated continuously during intermissions in the painting operation. I have found that even after a considerable length of time, if the gun is again operated, the paint in the line 61 will be found to be in a sufficiently atomized condition to start operation immediately. There is no failure in the painting such as occurs when air only is delivered and there is no spitting or other irregularity which occurs when the paint is delivered in irregular amounts.

There are many advantages in the operation of this system which will be referred to more fully at the end of the specification. I wish to point out, however, that if two diflerent types of paint are required, it is a very simple matter to change from one paint container to another by simply transferring the flexible hose l9. After taking the hose out of the first container, I may run the apparatus until all of the accumulated paint has been discharged so as to avoid mixing of the two types of paint. I may also run a solvent through the system before beginning to operate on the second type of paint so as to clean out the system entirely. This method of change is exceedingly simple and. requires only a very short length of time. As far as I know, there is no other system in use which permits such simple operation.

In the embodiment shown in Fig. 7, I provide a modified drive for the pump. In place of an electric motor, I utilize a small air motor 76 of any suitable type, but preferably a relatively small size rotary motor. This motor has its shaft directly connected to the pump I H and drives the pump in substantially the same way that it is driven by the electric motor, it being understood that substantially the same operating speeds are obtainable, The motor receives air through a flexible hose line 11 connected to a suitable source of supply. The air is exhausted from the motor through a flexible line 18 and the exhaust air is delivered to the atomizer I24 and has the same atomizing effect in the system as if the air supply for the atomizer were supplied directly from an original source. In this system, I employ the same type of relief valve I21, lift check valve I21, etc. In this modified form, I employ the same reference characters asemployed in the original embodiment to show corresponding parts, but in each case I employ the prefix I on the modification. The operation of the modified form is the same as the main form except for the modified drive.

Among the principal advantages of my present invention is the greatly decreased cost of manufacture and maintenance. I eliminate entirely the paint pressure tank usually employed and use only half as much hose as the most satisfactory present commercial systems. The entire mechanism is very much lighter. in weight and can be transported readily from one place to another. No special type of container 2| is needed, ordinary paint drumsbeing suitable for the pur-. pose. Since the operator has to support only a single hose and a relatively light gun, he can perform his duties easily during the. ordinary working day without fatigue, and consequently is in a position to perform more careful work during the entire day. My present system permits much greater production per day per operator, not only because .less time is required in mounting and adjusting the apparatus, but also because a greater volume of atomized paint may be delivered and the surface covered at a more rapid rate. Another feature which effects a tremendous saving in time, labor, expense, and the like, is that the entire apparatus can be left on the ground independent of how high the work is located, a positive delivery of paint being obtained under substantially any conditions. It is never necessary to lower containers for refilling or in fact to stop the operation at all. With the paint container on the ground, if it is necessary to refill, paint either can be poured into the container while the operation is proceeding, or the hose l9 can be transferred very quickly from one container to another. Finally, the apparatus may be operated with air at either a high or at a low pressure. On very high work it may be advantageous to employ a high pressure. When the work is close to the ground, the same or possibly even better results may be obtained with a low air pressure.

I have described my invention in detail, but I do not limit myself except as defined in the appended claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. In a single line liquid spray system of the character described, a continuously acting pump of a type to produce a constant volume flow therethrough and having intake and exhaust ports, a connection to said intake port adapted to be extended into an open vessel containing a supply of liquid to be sprayed, a pipe connected to said exhaust port, a nozzle connected with said pipe and extending into an atomizing chamber, means for delivering a gas under pressure to said atomizing chamber, means formaintaining the pressure of liquid in said pipe constant, a single hose line leading from the atomizing chamber and a spray nozzle connected to said hose line.

2. A spray system as defined in claim 13, wherein said valve comprises a spring pressed diaphragm exposed to pressure of the liquid in a pressure chamber connected to the discharge pipe, a relief valve adapted to be opened when the pressure in said chamber moves the diaphragm against the diaphragm spring, and means for delivering liquid passing said relief valve to said intake pipe.

3. A spray system as defined in 'claim 13, wherein said valve comprises'a spring pressed diaphragm exposed to pressure of the liquid in a pressure chamber connected to the discharge pipe, a relief valve adapted to be opened when the pressure in said chamber moves the diaphragm against the diaphragm spring, means for delivering liquid passing said relief valve to said intake pipe, and means for regulating the compression of said diaphragm spring.

4. In a single line liquid spray system of the character described, a continuously operated constant capacity pump, an atomizing device com prising an atomizing chamber and a nozzle for delivering liquid to the atomizing chamber, a discharge pipe leading from said pump and communicating with said nozzle, a source of liquid to be sprayed adapted to be supported in an open container, an intake conduit leading to said pump and having a portion thereof adapted to have its end submerged in the liquid, means for bypassing liquid from said discharge pipe to the intake conduit whereby to maintain the pressure in said discharge pipe substantially constant; means for delivering air under pressure to the atomizing chamber substantially at right angles to the direction of flow of liquid from said nozzle as the liquid passes said nozzle, whereby to atomize the liquid, a spray nozzle and a single hose line leading from said atomizing chamber to said spray nozle for receiving the atomized liquid and air for delivering the same to a point of application of the liquid.

7 5. In a spray system of the character described, a rotary pump having an intake port and a discharge port, an air motor connected to drive said pump and having an air intake port and an air exhaust port, means for connecting the intake port of the pump to a source of liquid to be sprayed, the liquid being under atmospheric pressure, an atomizing device including an atomizing chamber, a liquid delivery nozzle projecting into said chamber, a discharge pipe connected to said pump discharge port, a connection from said discharge pipe to the nozzle, an air connection from the exhaust port of the motor to the atomizing device so as to deliver air to said atomizing chamber, a hose line connected into said atomizing chamber, and a gun at the opposite end of said hose connection for controlling the delivery of air and atomized liquid therefrom.

6. In a spray system of the character described,

a rotary pump having an intake port and a discharge port, an air motor connected to drive said pump and having an air intake port and an air exhaust port, means for connecting the intake port of the pump to a source of liquid to be sprayed, the liquid being under atmospheric pressure, an atomizing device including an atomizing chamber, a liquid delivery nozzle projecting into said chamber, a discharge pipe connected with said pump discharge port, a connection from said dischargepipe to the nozzle, a check valve in said connection, an air connection from the exhaust port of the motor to the atomizing device so' as to deliver air to said atomizing chamber, a flexible hose line connected into said atomizing chamber, and a gun at the opposite end of said flexible hose connection for controlling the delivery of air and atomized. liquid therefrom. 7. A system as defined in claim 6, including means for by-passing variable proportions of the liquid from said discharge pipe back to the intake pipe whereby to maintain a constant pressure in said discharge pipe.

8. In a single line liquid spray system of the character described, an atomizing device including an atomizing chamber, a nozzle extending into said chamber, means for delivering liquid to be sprayed in a constant stream to said nozzle, means for delivering air under pressure to said atomizing chamber past the mouth of said nozzle at right angles to the direction of flow of liquid from the nozzle, a single hose line connected to said chamber substantially in alignment with the airdelivery to said chamber, and a spray gun at the opposite end of said hose line for spraying air and atomized liquid.

9. In a single line liquid spray system of the character described, a rotary pump having an intake port and a discharge port, means for driving said pump continuously, a flexible pipe forming part of a liquid line and having one end connected to the pump intake port and the other end adapted to be placed below the level of a liquid in an open container, means for maintaining a substantially constant pressure in said liquid line, an atomizing device including an atomizing chamber, a relatively small nozzle in said chamber, a connection between the pump discharge port and said nozzle, means for delivering air under pressure to said chamber, a single hose line leading from the atomizing chamber and a spray nozzle connected to said hose line.

10. In a single line liquid spray system of the character described, a base, a rotary constant volume flow pump having intake and exhaust ports secured on said base, a motor for operating said pump also secured to said base, pipes connected to said intake and exhaust ports, a pressure relief valve interconnecting the intake and discharge pipes, a flexible pipe connection to said intake pipe adapted to be projected below the level of liquid in an open container, an atomizing device including an atomizing chamber carried on said base, a relatively small liquid delivery nozzle projecting into the chamber, a pipe connection between said discharge pipe and said nozzle, an air delivery pipe connected to said chamber to deliver air past said nozzle, whereby to atomize the liquid, a flexible single line hose having one end connected to said chamber in line with the air delivery pipe, and a valve control spray gun at the opposite end of said flexible hose whereby to deliver the liquid in spray form from said gun.

11. In a single line liquid spray system of the character described, a base, a rotary pump having intake and exhaust ports secured on said base, a motor for operating said pump also secured to said base, pipes connected to said intake and exhaust ports, a pressure relief valve interconnecting the intake and discharge pipes, a flexible pipe connection to said intake pipe adapted to be projected below the level of liquid in an open container, an atomizing device including an atomizing chamber carried on said base, a relatively small liquid delivery nozzle projecting into the chamber, a pipe connection between said discharge pipe and said nozzle, an air delivery pipe connected to said chamber to deliver air past said nozzle, whereby to atomize the liquid, a

flexible single line hose having one end connected to said chamber in line with the air delivery pipe, a valve control spray gun at the opposite end of said flexible hose whereby to deliver the liquid in spray form from said gun, and a check valve disposed in said pipe connecting the pump discharge pipe with said nozzle, said system designed to permit recirculation of liquid through the pump and through said pressure control valve when the spray gun valve is closed and to prevent forcing liquid from said nozzle back into the pump discharge pipe.

12. In a spray system of the character described, an air motor connected to drive a pump and having an air intake port and an air exhaust port, means for connecting the intake port of the pump to a source of liquid to be sprayed, an atomizing device including an atomizing chamher, a liquid delivery nozzle projecting into said chamber, a discharge pipe connected to said pump discharge port, a connection from said discharge pipe to the nozzle, an air connection from the exhaust port of the motor to the atomizing device so as to deliver air to said atomizing chamber, a delivery conduit leading from said atomizing chamber, and a gun in said conduit for controlling the delivery of air and atomized liquid therefrom.

13. In a single line liquid spray system of the character described, a continuously operated constant capacity pump having an intake port and a discharge port, an intake pipe connected to the intake port, a discharge pipe connected to the discharge port, a by-pass and pressure regulating valve connected to said intake and discharge pipes to form a closed path between the pump. dis-, charge and intake ports, a connection into said intake pipe and adapted to be connected to a source of supply of liquid to be sprayed, a connection to the discharge pipe, and atomizing means adapted to receive said liquid from said last mentioned connection, said atomizing means comprising a chamber having a liquid carrying nozzle leading thereinto, means for spraying air to said atomizing chamber, means connecting the discharge pipe with said liquid carrying nozzle, a single hose line leading from said chamber, and a spray nozzle connected to said hose line.

HARLAN RICHARDS.