US3672645A

US3672645A - Container and stirrer for paint sprayer

Info

Publication number: US3672645A
Application number: US105003A
Authority: US
Inventors: Joseph L Terrels; Robert Meneses
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-01-08
Filing date: 1971-01-08
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A combination paint container and stirrer for use with a conventional spray gun. The stirrer is driven from the same source of air that operates the spray gun. A vent system of the shaft keeps the air pressure within the cup at the proper level, without allowing leakage of paint, even when the spray gun is positioned other than horizontally.

Description

United States Patent Terrels et al.

[451 June 27,1972

CONTAINER AND STIRRER FOR PAINT SPRAYER Inventors: Joseph L. Terrels, 6 Greenbank Ave.; Robert Meneses, 1308 W. Chester Pike, both of West Chester, Pa. 19380 Filed: Jan. 8, 1971 Appl. No.: 105,003

Related U.S. Application Data Continuation-impart of Ser. No. 772,559, Nov. 1, 1968, abandoned.

U.S. Cl ..259/122, 239/142 Int. Cl. ..B01f 7/16 Field ofSearch ..259/122, 107, 108, 111, 112,

[56] References Cited UNITED STATES PATENTS 3,041,052 6/1962 Dedoes ..259/122 3,412,937 1 H1968 Chamberlain ..239/142 2,959,358 11/1960 Vork ..239/330 3,042,310 7/1962 Franke et a1 ..239/142 Primary Examiner-Jordan Franklin Assistant Examiner-Geo. V. Larkin Attorney-Jackson, Jackson & Chovanes [57] ABSTRACT A combination paint container and stirrer for use with a conventional spray gun. The stirrer is driven from the same source of air that operates the spray gun. A vent system of the shaft keeps the air pressure within the cup at the proper level, without allowing leakage of paint, even when the spray gun is positioned other than horizontally.

3 Claims, 11 Drawing Figures PATENTEDJum 1972 3. 672,645

SHEET 1 [IF 3 III I l I INVENTO s efaaey L far/v25 ATTORNEYS PATEM'EDJmm 1972 3, 672 645 sum 2 [IF 3 I VENTORS Jo y/ Terra/a ar Aleneaes O MLM ,icaww ATTORNEYS CONTAINER AND STIRRER FOR PAINT SPRAYER This is a continuation-in-part of application, Serial No. 772,559, filed Nov. 1, 1968 and now abandoned.

This invention relates to a paint spraying device, and, more particularly, to a container assembly adapted for use with a conventional paint spray gun.

A purpose of the invention is to keep pigment suspended within a paint vehicle while spray painting.

A further purpose is to control the rotational speed of a paddle or stirrer operating in a pool of paint.

A further purpose is to provide a stirrer arrangement which is readily disassembled and assembled.

A further purpose is to provide a compact container having a paddle arrangement fully adaptable to the standard paint guns now on the market with no modifications necessary to attach and use.

A further purpose is to optionally provide a cup having graduations etched into its sides for correct proportions of in gredients to be mixed.

A further purpose is toprovide a cup of high strength, clear translucent plastic material, impervious to all solvents and all paint ingredients.

A further purpose is to permit the user to view the paint level at all times within the paint cup and, therefore, gauge the proper time to refill the cup.

A further purpose is toeliminate the possibility of running out of paint when partially through a critical area and risk having a change in color tone at the run-out point.

A further purpose is to mix paint within the cup itself, thereby eliminating the need of mixing in other containers and pouring into the cup.

A further purpose is to provide graduations etched into the sides of the cup which will permit adding exact proportions of paint as recommended by the paint manufacturer.

A further purpose is to reduce the preparation time prior to painting and thus give more on-the-job" painting and increase worker productivity.

A further purpose is to provide a constant control of speed of the agitator while painting which will assure a thoroughness of the paint mixture, particularly in metallic content paint.

A further purpose is to eliminate possible settling out" of the metallic content which would change the color tone and require repainting of the work piece.

A further purpose is to provide a control on a stirrer so that stirring can be eliminated entirely or controlled to any degree of speed necessary to hold the paint pigment in suspension suitable for spraying.

A further purpose is to exhaust air in the turbine chamber vertically upward to prevent the air exhaust from coming in contact with the wet spray surface and causing a ripple or marred surface which would require rework.

A further purpose is to provide a unitary lid construction including a turbine chamber and a paddle wheel shaft support.

A further purpose is to provide a finger control for manually starting the paddle or stirrer if necessary.

A further purpose is to stir the paint centrally within the cup.

A further purpose is to equalize air pressure within the paint cup to permit proper operation of the sprayer.

A further purpose is to prevent leakage of paint during operation of the sprayer.

Further purposes appear in the specification and claims.

In the drawings, I have chosen to illustrate one only of the numerous embodiments which appear in my invention, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIG. 1 is a perspective view of the device of the invention in combination with a conventional spray gun, which is shown in phantom.

FIG. 2 is a top plan view of the device shown in FIG. 1. FIG. 3 is a perspective view of the cup of the device shown in FIG. I.

FIG. 4 is a perspective view, in an upward direction, showing the bottom interior of a cap suitable for tightening on the cup of FIG. 3.

FIG. 5 is a bottom plan view, with the control valve partially broken away, of the cup assembly of FIG. 1.

FIG. 6 is a vertical elevation through the paddle shaft of the device of FIG. 1.

FIG. 7 is a fragmentary partial section taken on the line 7 7 of FIG. 6.

FIG. 8 is a longitudinal, vertical, sectional drawing of the vent construction of the invention, showing the vent in closed position.

FIG. 9 is a view similar to FIG. 8 showing the vent in open position.

FIG. 10 is an exploded view of the vent elements.

FIG. 11 is a plan section taken on line 11-1I of FIG. 10.

Extensive use is made of spraying in the application of paint to surfaces, particularly metallic surfaces, such as car bodies. conventionally, a source of air under pressure is passed through a nozzle, or gun, whereby a suction or vacuum is created which aspirates the paint from a source adjacent the gun to the work surface.

In many paints, and particularly in paints having a metallic pigment, there is a strong tendency for the pigment to settle in the liquid vehicle, resulting in an inconsistent and unsatisfactory paint application.

Efforts have been made to keep the pigment suspended uniformly throughout the paint during the application thereof by rotating, with air under pressure, a paddle wheel within the paint supply or source. See US. Pat. No. 3,042,310, to R. A. Franke et al., where a cup is immediately adjacent a spray gun, and US. Pat. No. 2,959,358, to W. D. Vork, where the paint is in a bulk source, such as a S-gallon can, wherein the paint is conveyed from the container to the gun by means of separate tubes. The air under pressure for rotating the paddle wheel is supplied from the same source as the air used with spraying. The present invention comprises an improvement in a paddle wheel stirring arrangement of the type wherein the cup is adjacent the gun.

In the present device, a conventional spray gun is readily, by means of suitable adaptors, attached to an assembly comprising a cup and lid, wherein the cup contains the paint and the lid supports the entire stirring mechanism, including a paddle shaft having paddles, a turbine and turbine chamber, a paddle speed control and an aspirator tube. In addition to yielding highly satisfactory results during spraying, the present arrangement provides a structure which can be readily disassembled and cleaned after each paint job.

Of critical importance in the present device is the venting arrangement between the interior of the cup and the atmosphere. In the prior art, means for equalizing air pressure within a cup having a stirrer therein were unsatisfactory, since either a vacuum was formed during use, and siphoning would stop, or the device leaked paint through a vent hole, particularly when the device was positioned horizontally.

The present means for venting to equalize air pressure is through the air chamber, through the hub surrounding the shaft and into the sealed paint cup. It employs a sensitive assembly of O-rings, spring retainers and springs located between the housing bushings. When assembled, the spring tension holds the upper O-n'ng firmly against the bottom face of the upper bushing thus keeping all material below this point.

The spring tension is so delicately balanced that the introduction of air into the air chamber to operate the turbine does not dislodge the O-ring to allow air into the cup. Only when the spray gun is triggered and the siphoning action begins does the O-ring become dislodged and air is permitted into the cup to supply needed air. In operation, the level of paint is lowered in the cup, as the material is being siphoned, and the head of air above the paint is depleted, forming a partial vacuum. This is a critical moment in the operation of the device, since, if this partial vacuum is not neutralized by incoming air, the fan or spray at the nozzle of gun gradually diminishes and finally stops. Hence, it is essential at this point that air, in very controlled amounts be admitted to maintain the pressure within the cup at least equal to the atmospheric pressure of air outside of the cup. The present means for venting accomplishes this.

More specifically, the present invention relates to an improvement over previously designed spray cups in that the method of equalizing air pressure is in itself unique and permits the user to spray vertically, horizontally and overhead if desired. Overhead spraying can be easily facilitated by a change in the siphon to draw the material from the back of the cup rather than the front of the cup.

Prior art hand type siphon cups attempting to spray to the present capabilities, would result in fouling the bearing areas around the shaft and having the stirring action stop or resulting in paint spillage through the vent hole and spoiling the paint job.

Desirably, the cup is constructed of a translucent plastic material wherein the quantity of paint within the cup can be readily observed during spraying. The paint cup can be refilled at a suitable break area in the work, thus avoiding depletion of the paint supply at a critical area with a corresponding break in appearance.

Referring to the drawings, the principal parts of the invention include a cup 20, a lid 21, an impeller 22, a paddle 23, an air line for operation 25, and a speed control 26. The cup has external threads 27 formed circumferentially at three places suitably equally spaced and equal in length. The bottom surface of the thread at 28 slopes downwardly and has thereon a bump 30 which engages in depression 31 on corresponding threads 32 formed in the lid 21. Cover 33, shown in FIG. 4, which is optionally secured to cup 20 to act as a closure when lid 21 is not engaged thereon, has the same type threads, and reference is made to such cover 33 for illustration. Cover 33 has a skirt 34 and a top 34'.

The lid 21 has formed therein an air chamber 35 which suitably follows in contour the form of impeller 22. The lid 21 is desirably formed in two

sections

36 and 37 which are held together by suitable fastening means, such as screws 38 which thread into liners 40 seated in closure openings 41.

Impeller 22 is fitted on shaft 42 supported in

bearings

43, 44 and 45, fitted in

extensions

46 and 47 in lid 21. Shaft 42 has flange 48 integrally formed thereon which bears against bearing 43 and prevents axial movement in an upward direction. Lock washer 50 engages shaft 42 at end 51 and also secures the shaft axially within the lid 21. An aspirator tube 52 extends downwardly adjacent the bottom of the cup 20 at 53 and is supported at its upper end within adaptor 54. Adaptor 54, which is best seen in FIG. 7, has a hex portion 55 which seats in a correspondingly shaped depression 56 within the boss 57 which is integrally formed with portion 36 of lid 21. Adaptor 54 has threads 58 at its upper end which receive lock nut 60 which is tightened against raised portion 61 of lid 21. A suitable opening 62 in the lid permits the upper portion of adaptor thread 58 to extend outside the lid 21.

A paddle wheel 23, as best seen in FIGS. 1 and 6, is force fitted on to the bottom of shaft 42. The shaft 42 is suitably of a cross shape in cross section. Paddle 23 has thereon inclined blades 64 which are adapted to pass through the paint to mix and stir together the pigment and vehicle. A gasket 65 extends within the lower surface of lid 21 and acts to seal the lid 21 to the cup 20 when the lid 21 and the cup 20 are connected by rotation of one with respect to the other. When the lid is so engaged, bump 30 extends into depression 31 on

threads

28 and 32, thus securing the lid with respect to the cup.

Air from a source of pressure comes through line 25, through T connection 25 diverted through line 95, and enters needle control valve 26 and escapes through orifice 27 into opening 28 of air chamber 35. The air entering strikes against the vanes 66 of impeller 22, rotating the impeller in a clockwise direction, as seen in FIG. 5. The O-ring seal 67 seals cylindrical surface 68 against bore 70 of housing 71 of the needle control valve 26. A tapered portion 72 concentrically fits within tapered opening 73, thus permitting air to enter into chamber 35. A thumb screw 75 having a threaded portion 76, engages internal threads 77 within housing 71 of the needle valve, permitting longitudinal adjustment of the tapered portion 72 within opening 73 allowing control of air into chamber 35. After forcing the vanes 66 of impeller 22 to rotate, the air escapes through exhaust holes 78 at the top of the turbine chamber.

The cup 20 has thereon suitable graduation 80, such as indications of pint contents, so that the user may judge the amounts contained therein, either as an indication of quantities to be mixed, or as the quantity remaining in the cup.

The entire assembly described in detail above is used in conjunction with a conventional spray gun 90, as shown in FIGS. 1 and 2. The spray gun is connected by means of a curved adaptor 91 to the aspirator tube 52 through a union 92 at the lower end, and the union 93 on spray gun 90 at the upper end.

T-connector 25' is connected to spray gun 90 by means of connector 94. Turbine air supply hose 95 is secured to air control valve 26 by clamp 96 at one end, and to T-connector 25 by clamp 96 at the other end. Quick disconnects are used at 94 and at air supply hose 25 connection to T-connector 25.

Referring to the drawings and particularly FIGS. 8 to 11, I show therein the venting arrangement for maintaining proper pressure within the cup at all times during spraying, including vertical, horizontal, and inclined spraying, without leaking paint to the atmosphere and without clogging the venting system.

Surrounding shaft 42 at its upper end, I show therein bushing 44 of a relatively soft metal, such as brass, having a shoulder 101, which extends radially outwardly from the bushing and seats on ledge 102 of portion 46 of the lid. Bushing 44 also has a sleeve portion and a slightly raised bead portion. The bushing is such that it clears the shaft even at the smallest diameter of the bore, whereby, as more fully explained later, air selectively passes along the shaft into the cup.

An upper O-ring 106 or teflon or other suitable material surrounds the shaft and forms a close fit thereon, immediately below the upper bushing 101. An upper ring retainer 107, having a flange portion 108 and a sleeve portion 1 10 abuts against the O-ring 106. A helically wound compression spring 111 extends around the shaft 42 and between upper spring retainer 107 and lower spring retainer 1 12.

A lower O-ring 113 of the same construction as O-ring 106 extends around the shaft and abuts against the shoulder of the lower spring retainer 1 12 and, in turn, rests on the lower bushing 43. Lower bushing 43 is dissimilar to bushing 44 in that the bore of the bushing is slightly inclined longitudinally upward, for instance, desirably about 7 from the longitudinal, and it has extending radially thereon a plurality of grooves 115 as best seen in FIG. 1 1, and is inverted from the posture of bushing 44.

As seen in FIG. 8, the venting system is closed and no air is permitted into the siphon cup, along the shaft 42. This blockage of air is achieved by the expansion of spring 111 against its spring retainers 107 and l 12, thus forcing the upper O-ring 106, while it is in sealing relationship against the surface of O-ring 106, against the lower surface of bushing 44. The lower O-ring 113 rests against lower spring retainer 1 l2, and against the upper surface of bushing 43. It will be seen that although lower O-ring 113 is in fitting and close relationship to the shaft, there is no blockage of any possible flow past the lower O-ring 113, since the lower bushing 43 has radially extending slots 115, which cannot be blocked by the lower 0- ring.

All the sealing takes place at the upper O-ring 106 between the shaft 42 and the bushing 44.

When the pressure, or head, of air in the cup 20 drops to a point where a vacuum is just about to be created in the cup, the tension spring 111 compresses, since the pressure within the turbine chamber is acting against upper O-ring 106, thus forcing the upper O-ring 106 to slide longitudinally downward along the shaft, permitting a flow of air through the bore of the upper bushing 44, downwardly, between the shaft 42 and the lower part of the bore of the bushing 44. The flow of air then proceeds along the recessed portion of the housing 46 at 116, and downwardly and then radially inwardly through slots 115 of the lower bushing 43, and then down onto the top of the flange 48, extending outwardly from the shaft 42.

During operation, the shaft 42 is rotating and flange 48 tends to spin, by centrifugal means, any paint which may be in the upper part of the cup, away from the vent construction. Air travel, when the vent arrangement is open, as in FIG. 9, is shown by arrows 117 which trace the path of air as it comes into the interior of the cup.

Ambient or atmospheric air will continue to pass into the cup, replacing the paint which is siphoned from the cup during spraying, at a rate which keeps the pressure within the cup at a point very slightly above atmospheric, or just at the point where a vacuum is about to occur. In the event that there is a pressure buildup within the cup, the spring 111 will expand and force the upper O-ring 106 against the lower portion of the upper bushing 44 as shown in FIG. 8, thus closing the vent.

In operation, the paint may be prepackaged in cup 20 with cover 33 attached thereto. This may be prepackaged by the paint manufacturer, or prepared by the individual user.

When the user is ready to spray, the cover 33 is removed from the cup 20, and the lid 21 with its component elements attached is assembled to cup 20. Where the paint is not prepackaged, cup 20 is suitably filled from a bulk source.

The assembled lid 20 and cover 21 are then connected to spray gun 90 by adaptor 91 by tightening

unions

92 and 93, and by assembling T-connector 25 to spray gun 90 through connector 94, with air supply hose 25 connected thereto as shown in FIGS. 1 and 2. Main air pressure is applied through hose 25. Air control valve 26 is then adjusted by suitably setting control knob 75. It will be seen that the desired degree of stirring can be obtained independently of any spray action through gun 90. If desired, an initial twist can be imparted manually to the shaft 42 by grasping end 51 with the fingers and rotating the shaft. After the desired initial stir, if any, is obtained, spray gun 90 is operated in the conventional manner by depressing the trigger. Control valve 26 can be readjusted at any time to give the proper stirring during spraying.

During operation, paint is siphoned from the cup in the usual manner. A low pressure zone is created in the spray gun from the movement of the spray air. Atmospheric pressure within the paint cup 20, in the space above the paint, forces paint up through the siphon tube 52, to the spray gun nozzle where it is carried in spray form to the work. The vent construction of the invention will initially be closed, as seen in FIG. 8, and no air will be entering the cup. As the paint in the cup is used, and the level of paint recedes, the pressure of the air within the cup will drop, since the same air is now occupying a greater space. In this condition, the spring 111 holds the upper O-ring firmly against the bottom face of the upper bushing, thus keeping all material below this point.

The compression characteristic of the spring are such that the introduction of air into the air chamber to operate the turbine does not dislodge the O-ring to allow air to enter the cup. Only when the spray gun is triggered and the siphoning action begins does the O-ring become dislodged and air is permitted to enter into the cup to supply needed air. By means of the present vent arrangement, the air pressure in the cup is kept at least equal to the atmospheric, without permitting paint to leak out of the vent. At the same time, the working parts of the vent construction are kept clean of paint by the wiping action from the air entering from the turbine chamber into the cup. When the vent is closed, under the spring action, no paint is trapped in the mechanism.

It should be noted that the source of air for supplying the cup, and operating the vent, is the turbine chamber, which generally has air above atmospheric pressure, which is necessary to drive the turbine.

Where the cup is translucent, the paint level may be observed during spraying, to determine when is the best time to refill. Markings 80 can be utilized to indicate quantities of paint being added.

As can be seen from the detailed description of the construction, the entire assembly can be quickly disassembled and assembled for cleaning.

In view of our invention and disclosures, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the structure shown, and we, therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. In a combination paint container and stirrer for use with a paint spray gun and an air supply under pressure:

a. a cup; and

b. a removable lid having 1. fastening means for securing the lid to the cup, 2. a turbine chamber, 3. an air inlet and an air outlet to the turbine chamber, 4. a control valve in the air inlet, 5. a bore for receiving a shaft, and 6. a shaft journalled in the bore, and having a. a turbine wheel at its upper end rotatably positioned in the turbine chamber and b. a paddle wheel at its lower end adapted to rotate near the bottom of said cup, 7. vent means for selectively passing air from the turbine chamber to the cup comprising a. an upper bushing fixed in the bore and surrounding the turbine shaft, and having a lower surface,

an upper O-ring surrounding, and in sealing relation to, the shaft and free to slide longitudinally thereon,

and selectively contact the lower surface of the upper bushing, and positioned on the shaft immediately below the upper bushing,

c. an upper spring retainer surrounding the shaft and concentric therewith, and having an upper surface adapted to contact the upper O-ring at its lower surface,

d. a helical compression spring surrounding the shaft and in spring engagement with the upper retainer and adapted to exert a force against the upper retainer, forcing it upwardly,

e. a lower spring retainer engaging the helical compres- I sion spring and adapted to move longitudinally with respect to the shaft,

f. a lower O-ring in contact with the shaft, and adapted to slide thereon, positioned on the shaft below the lower spring retainer, and

g. a lower bushing surrounding and joumalling said shaft, and fixed in the bore, and having radial air passages extending therethrough,

wherein said upper and lower bushings are fixedly secured in the lid bore, and said first upper and lower O-rings and upper and lower spring retainers, are adapted to move longitudinally along said shaft, and wherein said upper O- ring is adapted to selectively slide into sealing relationship with the shaft and upper bushing when no air is needed in the cup, and selectively slide away from the upper bushing wherein air flow is permitted between the turbine chamber and the cup when air is needed in the cup, 8. an aspirator tube supported on the lid and extending into the cup adjacent the paddle wheel, and 9. fittings on the lid for attachment to the paint spray gun and the air supply. 2. The device of claim 1, wherein the cup is composed of a translucent plastic material.

Claims

1. In a combination paint container and stirrer for use with a paint spray gun and an air supply under pressure: a. a cup; and b. a removable lid having 1. fastening means for securing the lid to the cup, 2. a turbine chamber, 3. an air inlet and an air outlet to the turbine chamber, 4. a control valve in the air inlet, 5. a bore for receiving a shaft, and 6. a shaft journalled in the bore, and having a. a turbine wheel at its upper end rotatably positioned in the turbine chamber and b. a paddle wheel at its lower end adapted to rotate near the bottom of said cup, 7. vent means for selectively passing air from the turbine chamber to the cup comprising a. an upper bushing fixed in the bore and surrounding the turbine shaft, and having a lower surface, b. an upper O-ring surrounding, and in sealing relation to, the shaft and free to slide longitudinally thereon, and selectively contact the lower surface of the upper bushing, and positioned on the shaft immediately below the upper bushing, c. an upper spring retainer surrounding the shaft and concentric therewith, and having an upper surface adapted to contact the upper O-ring at its lower surface, d. a helical compression spring surrounding the shaft and in spring engagement with the upper retAiner and adapted to exert a force against the upper retainer, forcing it upwardly, e. a lower spring retainer engaging the helical compression spring and adapted to move longitudinally with respect to the shaft, f. a lower O-ring in contact with the shaft, and adapted to slide thereon, positioned on the shaft below the lower spring retainer, and g. a lower bushing surrounding and journalling said shaft, and fixed in the bore, and having radial air passages extending therethrough, wherein said upper and lower bushings are fixedly secured in the lid bore, and said first upper and lower O-rings and upper and lower spring retainers, are adapted to move longitudinally along said shaft, and wherein said upper O-ring is adapted to selectively slide into sealing relationship with the shaft and upper bushing when no air is needed in the cup, and selectively slide away from the upper bushing wherein air flow is permitted between the turbine chamber and the cup when air is needed in the cup, 8. an aspirator tube supported on the lid and extending into the cup adjacent the paddle wheel, and 9. fittings on the lid for attachment to the paint spray gun and the air supply.

2. a turbine chamber,

2. The device of claim 1, wherein the cup is composed of a translucent plastic material.

3. The device of claim 2, wherein the cup has graduations marked thereon.

3. an air inlet and an air outlet to the turbine chamber,

4. a control valve in the air inlet,

5. a bore for receiving a shaft, and

6. a shaft journalled in the bore, and having a. a turbine wheel at its upper end rotatably positioned in the turbine chamber and b. a paddle wheel at its lower end adapted to rotate near the bottom of said cup,

7. vent means for selectively passing air from the turbine chamber to the cup comprising a. an upper bushing fixed in the bore and surrounding the turbine shaft, and having a lower surface, b. an upper O-ring surrounding, and in sealing relation to, the shaft and free to slide longitudinally thereon, and selectively contact the lower surface of the upper bushing, and positioned on the shaft immediately below the upper bushing, c. an upper spring retainer surrounding the shaft and concentric therewith, and having an upper surface adapted to contact the upper O-ring at its lower surface, d. a helical compression spring surrounding the shaft and in spring engagement with the upper retAiner and adapted to exert a force against the upper retainer, forcing it upwardly, e. a lower spring retainer engaging the helical compression spring and adapted to move longitudinally with respect to the shaft, f. a lower O-ring in contact with the shaft, and adapted to slide thereon, positioned on the shaft below the lower spring retainer, and g. a lower bushing surrounding and journalling said shaft, and fixed in the bore, and having radial air passages extending therethrough, wherein said upper and lower bushings are fixedly secured in the lid bore, and said first upper and lower O-rings and upper and lower spring retainers, are adapted to move longitudinally along said shaft, and wherein said upper O-ring is adapted to selectively slide into sealing relationship with the shaft and upper bushing when no air is needed in the cup, and selectively slide away from the upper bushing wherein air flow is permitted between the turbine chamber and the cup when air is needed in the cup,

8. an aspirator tube supported on the lid and extending into the cup adjacent the paddle wheel, and

9. fittings on the lid for attachment to the paint spray gun and the air supply.