US2687739A

US2687739A - Control mechanism for spraying apparatus

Info

Publication number: US2687739A
Application number: US188556A
Authority: US
Inventors: Shelburne Augustine; John T Shelburne
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-10-05
Filing date: 1950-10-05
Publication date: 1954-08-31
Anticipated expiration: 1971-08-31

Description

Aug- 31, 1954 A. sHELBURNE ETAL 2,687,739

CONTROL MECHANISM FOR SPRAYING APPARATUS Filed Oct. 5, 1950 4 Sheets-Sheet l 27p v O 4. 3V 5 sw] g @Uve/JEVS Aug- 31, 1954 A. sHELBURNE ETAL 2,687,739

- CONTROL MEcHANIsM FoR SPRAYING APPARATUS Filed Oct. 5, 1950 4 Sheets-Sheet 2 @TTG/@HEHE Aug. 31, 1954 A. SHELBURNE ErAL 2,687,739

CONTROL MEOHANISM FOR sPRAYING APPARATUS Filed Oct. 5, 1950 4 Sheets-Sheet 3 Allg' 31, 1954 A. SHELBURNE Erm.

CONTROL rAEcHANIsM FOR SPRAYING APPARATUS 4 Sheets-Sheet 4 Filed oct.. 5, i950 paez/smv@- sms-suene ./aH/v n sf/aeueA/E INVENToRs W d ma @rra/@News WAAAAA Patented Aug. 31, 1954 OFFICE `CONTROL MECHANSM FOR SPRAYING APPARATUS Augustine Shelburne, San Marino, and John 'I'. Shelburne, Whittier, Calif.

Application October 5, 1950, Serial No. 188,556 (c1. 1ere-87) 4 Claims.

This invention relates to a valve or to a device adapted to be inserted in a fluid conducting conduit and which when the conduit is closed will be effective to actuate auxiliary apparatus. A valve of this character can be employed under a wide variety of different circumstances including spraying apparatus for spraying liquid and like coatings. I

This application is a continuation-in-part of our previous application entitled Control Mechanism for Spraying Apparatus, Serial No. 81,192, led March 12, 1949, and incorporates `all of the subject matter of said application. Said prior application Serial No. 81,192 is now abandoned.

In the usual apparatus for spraying liquid coatings a supply of compressed air is delivered through a conduit or hose to the air outlet of a spray gun. The liquid coating material is pumped from a reservoir or container through another conduit to the liquid outlet from the spray gun. The pump in the reservoir that pumps the liquid therefrom to the spray gun is operated by compressed air from the air source that supplies the spray gun. When the spray gun is shut oir it is desirable to have the mere closing of the air valve at the spray gun become effective to shut oi the supply of compressed air to the air pump. It is also desirable to relieve the pressure that may be in the air pump and to also open the liquid conducting conduit that conducts the liquid to the spray gun so as to relieve the pressure therein.

If the pressure in the liquid conducting conduit` `is allowed to remain when the spray gun is shut off the subsequent opening of the valves in the spray gun will cause a surge of liquid to take place through the gun and a solid stream of liquid is frequently discharged before there is an opportunityfor the released air to convert it into a spray. Relieving the pressure in the liquid con- 'ducting conduit and allowing the escaping liquid to drain back to the reservoir is therefore desirable and can be readily accomplished by use of the improved valve.

It is therefore anobject of the present invention to provide an improved spraying apparatus or similar apparatus and particularly to provide a valve used therein which is so designed that when the trigger ofthespray gun is released this I operation is automatically effective to cause the valve to operate and thus perform operations such as turning off the `air supply to the air pump, releasing the air pressure in the air pump` and `opening the liquid conduit to the spray ,gun to relievethe pressure therein. These operations` can be performed even though the spray gun is remotely located with relation to the valve, the reservoir, or the air pump.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a diagrammatical view of a spraying apparatus embodying the present invention;

Fig. 2 is a vertical section through the valve used therein illustrating the valve in its normal position wherein compressed air Vand liquid coating material are being supplied to the spray gun;

Fig. 3 is a view similar to Fig.` 2 but illustrating the valve in that position which it assumes when the supply of compressed air is turned o at the spray gun;

Fig. 4 is a sectional view through a modied or alternative form of construction;

Fig. 5 is a sectional view through another modied form or alternative form of construction; and

Fig. 6 is a schematic view of th device in Fig. 5 showing the parts in that position which the parts will assume when the supply of compressed air is turned on at the spray gun.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, IIl indicates a conduit such as a hose leading from a source of compressed air such as, for example, an air compressor. This conduit is connected to a valve mechanism generally indicated at I I from which a compressed air conduit I2 leads to a spray gun I3 the valves of which are controlled by a ltrigger I4'. I5 indicates a container or reservoir adapted to contain a liquid It which is to be sprayed by the spray gun I3. This liquid is pumped from the reservoir into a liquid conduit Il by means of `an air pump. The air pump employed may conform to any conventional type of pump used for this purposebut is illustrated as having a cylinder IIB within which is recirocable a piston I9. The piston I9 reciprocates a sucker rod 20 connected to a pump piston 2l that is reciprocable over a standing valve 22. A valve mechanism (not shown) controls` the supply of compressed air to the opposite ends of the cylinder i8 from a conduit 23 so that when compressed air is sup plied to the pump through conduit 23 :from the valve mechanism at II the pistons i9 and 2l will be vertically reciprocated to pump the liquid It from the reservoir I5 into the liquid conduit Il.

This liquid is conducted by the conduit I7 to the spray gun I3. The conduit I'I has a T 25 incorporated therein the lateral outlet of which has an upwardly divergent throat 25 terminating in a valve seat on which a pressure relief valve 2l is adapted to seat. When this valve is in unseated or open position, pressure in the liquid conduit Il will be relieved and excess liquid can drain therefrom back. into the reservoir Iii through a drain conduit 28.

The valve mechanism II which forms an important part of the present invention consists of a body 30 having an inlet 3l to which the compressed air conduit IIJ is connected. The primary outlet from this body is indicated at 32 and is connected to the conduit I2 which leads to the spray gun I3. The body provides a cylinder 33j within which there is reciprocable a piston 3d equipped with a cup leather or equivalent sealing means indicated at 35. This piston is normally urged downwardly by means of a compression spring 3S that is compressed between the top of the piston and a cap 31 screwed onto the body. In the bottom of the cylinder 33 there is a recess or well 38 into which a cylindrical extension or valve closure 39 on the bottom of the piston is receivable. This valve closure carries a yieldable seating material 40 adapted to engage with a valve seat il at the bottom of the well and which surrounds an outlet 42. The piston and cylindrical valve closure carries a tappet 43 engageable with a poppet valve 44 that is slidably mounted in the body 3B and which is urged into its uppermost or seating position by means of a compression spring A5. The head of the poppet valve M has one or more apertures 46 formed therein opposite the outlet 42 but outwardly of these apertures the head of the poppet valve is adapted to seat on a seating surface surrounding the outlet and the poppet valve thus controls egress through one or more exhaust ports lil. To this extent the poppet valve lill may be regarded as an exhaust valve in that it controls the exhaust ports 4l. Below the head of the poppet valve 44 a second outlet 4S is formed in the body'S to which the conduit 23" that leads to the air pump is connected. Below this outlet there may be additional passages Ils which lead to the top of a diaphragm chamber I). A diaphragm 5I extends across this chamber so that its upper surface is exposed to air pressure that passes downwardly to the diaphragm chamber 50 through the passages 49. The underside of the diaphragm 5I is exposed to atmospheric pressure throughv one or more breather ports 52. The diaphragm is connected to the relief valve closure 2l such as by a stem 53. A bypass 54 connects the outlet 32 with the top of the cylinder 33.

The operation of the above described apparatus is, brey, as follows: When the trigger I4 on the spray gun is depressed, opening the valves of the spray gun, pressure in the conduit i2 is reduced.

The pressure of the compressed air conducted through the conduit lil to cylinder 33 is eiective against the underside of the piston to lift the piston 34 against the action of the compression spring 3E. This is so because there is a pressure drop between the space on the underside of the piston and the entrance to the outlet 32 and also because there is a pressure gradient from the exit o1" the inlet Si across the bottom of the piston to the entrance to the outlet 32. It will also Y be noted that the volume of air above the piston is fixed so that the pressure above the piston will always be substantially that existing in port 32 and when the pressure in port 32 drops there will 4 be a very immediate drop in pressure above the piston. This action causes the valve mechanism to assume a position as illustrated in Fig. 2 wherein compressed air can readily pass from conduit I0 and through conduit i2 to and through the spray gun. When the piston 34 is in its upper position, as shown in Fig. 2, the cylindrical valve 319 is withdrawn from the well 3S so that the outn let i2 is opened to receive compressed air from the compressed air source. This air passes downwardly through the ports i5 through the outlet d@ and conduit 23 to the air pump causing liquid to be pumped from the reservoir through the liquid conduit Il' to the spray gun. The pressure of the air released through the ports i5 is also eiective through the passages il@ to depress the diaphragm 5I causing the pressure relief valve 2l to be firmly maintained on its seat.

When the trigger I4 of the spray gun is re leased, allowing the valves of the spray gun to close, the closing of the conduit I2 causes pressure to be built up therein. This pressure quickly equalizes with the incoming pressure through conduit Il] and is conducted through the bypass 54 to the top of the cylinder The piston 34 consequently commences to descend from the position shown in Fig. 2 to the position shown in Fig. 3 and upon the entry of the cylindrical valve 39 into the well 3S a portion of the underside oi the piston 34 is isolated from the upward eiect of incoming pressure thereon. Consequently the pressure in the cylinder 33 on top of the piston coupled with the force exerted by the compression spring 35 forces the piston into its lowerrnost position wherein the resilient material i3 seats on the seatV GI and the outlet e2 is largely closed by the piston. The closing of the outlet stops all further supply of compressed air to the air pump through outlet d3 and conduit 23 so that the air pump is caused to stop operating. However it is desirable to additionally relieve the cylinder oi the air pump of pressure and to this end the tappet 43 unseats the poppet valve dll thus opening the exhaust ports 47 and consequently releasing pressure to the air pump. The opening of the exhaust ports il to atmosphere causes the pressure effective on both sides of the diaphragm 5I to quickly equalize and when this takes place the pressure in the liquid conduit il' can be re lieved in that it then can unseat the pressure relief valve 2l. Liquid in the liquid conduit that is thus allowed to escape may drain back into the reservoir I5 through the drain conduit 23.

When operation of the spray gun I3 is Subsequently resumed by depressing the trigger I4, pressure in the conduit I2 is relieved and incoming pressure from conduit It is eective to return the piston 3ft to the position shown in Fig. 2. However, as the pressure in the liquid conduit I'I has been relieved as previously explained, there is no danger of a surge of liquid being discharged from the spray gun at the time of opening the valves of the spray gun by the trigger I4. In Fig. 4 the construction of the valve is substantially the same as previously described and consequently similar reference characters are applied to corresponding parts. In this construction, however, the bottom of the body 30 of the valve is closed below the outlet 48 by means of a plug 55. Such a construction may be employed whenever it is unnecessary to relieve the pressure in the liquid conduit I'I. This type of construe* tion may be employed whenever it is desired to automatically shut off the supply of compressed air through the outlet 48 on closing the valves of the spray gun which may beremotely located from the balance of the apparatus. i

It will be appreciated from the above described construction that the piston 34 and its cylindricalv valve 39 are in eiTecta type of differential valve in that when the valve 39 is openinrcoming pressure is effective over the entire bottom surface of the piston. However, when the spray gun is closed and the valve 39 has entered the well 38 the incoming pressure is effective on only a por'- tion of the bottom surface of the piston and consequently the back pressure in the conduit |2 conducted through bypass 54 and cooperating with the effect of the spring 36 can force the piston downwardly with positive action.

Figs. 5 and 6 show another modified form of the invention wherein there is a valve body having an inlet 1| and a primary outlet 12. There is a cap member `which is adapted to be secured to body 18 by screws 16, said cap member securing the edges of a diaphragm 11 between itself and the valve body 10 `as shown in Fig. 5. There is adiaphragm chamber 80 provided by ca'p member 15 and valve body 10 which diaphragm chamber is divided by diaphragm 11.

Valve 18 provides a centralbore 82 which connects the inlet 1| to the outlet 12 at all times. Within bore 82 there is a stem 85 having spaced lugs 86 to guide the stem member, said stem member being connected at its upper end to the lower member 89 of two diaphragm-clamping members 89 and 90 which diaphragm-clamping members are clamped onto the central portion of the diaphragm 11 by a threaded central stud 92 1 which is threaded into the lower member 89. The upper diaphragm-clamping member 10 has a sleeve 95 extending upwardly therefrom, which sleeve contains a compression spring 96 which is contained at its upper end by a threaded cap 98 which threads into the upper end of cap member 15. Valve body 10 is formed to provide a valve seat |80 which is adapted to be closed by a yieldable valve member |0| which is secured to stem 85 by a tappet |03, said tappet being threaded into the lower end of stem member 85,

as shown in Fig. 5.

The tappet |03 extends through the lower end of bore 82 and engages the upper of leaf springs |05 and |06 which are secured by screw |88 into the valve body 10. `Leaf springs |05 and |06 are initially formed to urge a poppet valve |88 to` seat on a seat 0 formed in body 10. Poppet valve |88 is provided with a` yieldable pad ||2 which engages the seat ||0 to close an outlet port H5. I I5 is an exhaust port similar to ports 41 inFig. 4, and serves to relieve pressure to the air pump. There is an outlet 28 provided by valve body 10, outlet |20 being adapted to be connected to an air pump `to supply air thereto when valve |8| is in open position. There is a diaphragm |22 secured between body 10 and a diaphragm chamber-forming member |25, said diaphragm chamber-forming member and the lower portion of valve body 10 providing a chami container. The` inlet port |35 is adapted to be connected to a liquid line.

There is a bypass passageway |48 formed in body 18 and cap member 15 which leads from primary outlet 12 to the back of diaphram 11.

The device shown in Fig. 5 operates similarly to the valves shown in Figs. 2 and 3, and when the valve in the spray gun is closed the pressure on opposite sides of diaphragm 11 is equal and therefore, the valve member |0| engages its seat |88 closing the supply of air to the air pump outlet |20 at the same time opening the poppet valve |08 to relieve any pressure to the air pump. The spring 96 aids valve member |8| in seating on its seat. When the valve in the spray gun is open by depressing the trigger there a drop in pressure in theprimary outlet 12 and a corresponding drop in pressure above the diaphragm 11. There is a drop in pressure between the outlet 12 and the chamber on the underside of diaphragm 11 due to the right angle turns and the normal pressure gradient so that the pressure on the underside of the chamber when the trigger on the spray gun is depressed, is higher than the outlet 12 and since the pressure above the diaphragm 11 is equal to the pressure in the outlet 12 the diaphragm will be bowed upwardly to the position shown in Fig. 6, thereby opening valve |8| andallowing the air under pressure to pass through the outlet |28 to the air pump, thereby pumping liquid. At the same time the poppet valve |88 is closed by the leaf springs |05 and |06 since the tappet |83 has moved upwardly as shown in Fig. 6.

The underside of the lower diaphragm |22 is vented by passageway |50 to the atmosphere so that when poppet valve |08 is closed and air under pressure is admitted to the chamber above lower diaphragm |22, diaphragmA |22 will be depressed as shown in Fig. 6, thereby closing valve |30 and thereby closing the communication between the liquid line and the drain.

When the valve onv the spray gun is closed the pressures on opposite sides of diaphragm 10 will be equalized so that the spring 96 will be effective to close valve |8| opening poppet valve |08, thereby relieving the pressure in the air pump and communicating the upper portion of lower diaphragm |22 with the atmosphere thereby balancing the pressures on opposite sides of this diaphragm so that it returns to its neutral position opening valve |30 and allowing liquid in the liquid line to return through a return line, such as 28, from liquid outlet |32 to the liquid container.

The spring 96 is stronger than the springs |85 andy |06 so that spring 96 is` sufiicient, when di` aphragm 11 is balanced to force the valve |0| closed and open poppet valve |08 against the resistance of springs and |86. However, spring 96 is weak enough so that when the diaphragm 11 is unbalanced by the valve in the spray gun being open so that the pressure in outlet 12 drops that` the diaphragm will move upwardly against the resistance of spring 96 opening valve |0|.

While the invention has been described in conjunction with a paint spraying apparatus it will be appreciated that it is not necessarily restricted thereto but may be employed wherever the conduits I8 and |2 conduct a fluid of any character. The purpose of the construction is to cause the closing of conduit |2 and the building up of back pressure therein to become effective to perform other operations such as the shutting off of the supply of compresed air to the air pump, the

openmg of the exhaust portsll, and the release of the pressure relief valve 2l. VMany other fund tions could also be performed by the descent'of the piston 34 in addition to or substitution for the operations or functions herein described.

Various changes may be made in the details of construction Without departing from the spirit and scope of the invention as dened by the appended claims.

We claim:

l. A valve of the class described comprising a valve housing having a compressed air inlet and outlet adapted to be connected to a source of compressed air and to an air conduit of a spray gun respectively, a second outlet leading from the housing adapted to be connected to an air pump, a drain valve and a seat Within the housing adapted to be connected to a liquid conduit leading to a spray gun, a diaphragm connected to the drain valve exposed on one side to atmospheric pressure, a pressure-responsive member in the valve housing exposed on one side to pressure in the inlet and exposed on the other side to pressure in the outlet, a valve carried by pressure-responsive member for controlling flow from the inlet to the second outlet simultaneously with flow from inlet to rst `outlet being controlled by said member, means for conducting pressure from the second outlet to the other side of the diaphragm whereby on closing egress through the first mentioned outlet flow from the inlet to the second outlet will be discontinued and pressure on the diaphragm urging the drain valve to close will be relieved, and an air exhaust assembly for relieving pressure on the diaphragm resulting in air pressures being made equal.'

2. A valve of the class described comprising a vbody having an inlet adapted to be connected to a compressed air source, an outlet from the body adapted to be connected to a spray gun, a second outlet from the body adapted to be connected to an air pump, a bleeder port adjacent the second outlet, a bleeder valve controlling the bleeder port and urged into closing position, a pressure-responsive member in the body exposed on one side to inlet pressure and exposed on the other side to outlet pressure, a valve closure carried by the pressure-responsive member adapted to close flovf from the inlet to the second outlet simultaneously With now from inlet to rst outlet being controlled by said member, a tappet carried by said valve closure engageable with the bleeder valve to open the bleeder valve when the first mentioned valve is closed, a diaphragm housing having a diaphragm therein exposed to pressure in the second outlet on one side and exposed to atmospheric pressure on the other, and a drain valve connected to the diaphragm so as Vto be Voperable thereby, saiddiaphragm and drain valve being responsive to pressures applied to the pressure-responsive member.

3. A valve of the class described comprising a housing having an inlet and an outlet, a pressure-responsive member responsive to pressures therein, a valve associated with the pressure-responsive member adapted to open when the pressure in the outlet is less than the pressure in the inlet and to close when the pressure in the outlet equalizes with the pressure in the inlet, a second outlet in the valve housing on the opposite side of the valve from the inlet, said second outlet being opened and closed by said valve simultaneously with the opening and closing of said inlet and iirst outlet, one or more bleeder ports adjacent the second outlet, and a bleeder valve controlling the bleeder ports operable by the rst mentioned valve to close the bleeder ports When the second outlet is open to the inlet and to open the bleeder ports when the second outlet is closed to the inlet.

' 4. A Valve of the class described comprising a housing having an inlet and an outlet, a pressure-responsive member responsive to pressures therein, a valve associated with the pressure-responsive member adapted to `open when the pressure in the outlet is less than the pressure in the inlet and to close when the pressure in the outlet equalizes with the pressure in the inlet, a second outlet in the valve housing on the opposite side of the valve from the inlet, said second outlet being opened and closed by said valve simultaneously with the opening and closing or" said inlet and irst outlet, one or more bleeder ports adjacent the second outlet, a bleeder valve controlling the bleeder ports operable by the nrst mentioned valve to close the bleeder ports when the second outlet is open to the inlet and to open the bleeder ports when the second outlet is closed to the inlet, and a diaphragm housing having a diaphragm therein exposed to pressure in the second outlet on one side and to atmospheric pressure on the other and a drain valve connected to the diaphragm arranged to close when pressure is in thesecond outlet and to be opened when the second outlet is closed to the inlet.

References Cited in the le of this patent UNITED STATES PATENTS NumberV Name Date 1,196,691 Hopkins Aug. 29, 1916 1,765,398 Birkenmaier June 24, 1930 2,223,044 Miller Nov. 26, 1940 2,447,408 Griswold Aug. 17, 1948 2,545,246 Tucker Mar. 13, 1951 2,558,681 Hachmeister June 26, 1951