GB2031758A - Spray gun - Google Patents

Abstract

A spray gun in particular for spraying viscous materials such as cementitious mixes has a body containing a rotatable control member or spool 22. This may be remotely actuated and controls the feed of compressed air from passage 14 and material to be sprayed from passage 18. In a solvent wash mode of operation, e.g. using water from passage 16 the gun can be washed out, by providing an extra control port in the spool. <IMAGE>

Description

SPECIFICATION Spray gun This invention relates to a spray gun for spraying materials such as cementitious mixes. The gun is also useful for spraying other materials, particularly quick setting mixtures.

Spray guns are known and normally receive pumped material to be sprayed, and compressed air, from suitable sources. The material and the air are fed into a body of the gun via suitable fittings or tappings. For control purposes, the known guns include a means of interrupting the flow to a nozzle of the gun. It has become apparent that an improvement in the manner of control is desirable.

According to the invention, there is provided a spray gun having a body with a bore therethrough and laterally-extending passages which connect the bore with respective tappings or fittings on the exterior of the body, a rotatable control member located in the bore, and ports in the control member which can connect passages selected according to the rotary position of the control member with a gallery passage in the body leading to a nozzle orifice of the gun.

Also according to the invention, there is provided a spray gun which has a body with passages for air, solvent liquid, and the material to be sprayed all leading to a bore in the body within which is located a rotatable control member, the body having a longitudinally extending further passage connected to the bore and to an exit chamber adjacent to a nozzle of the gun, and the control member having respective ports for co-operation with the respective passages in the body, the arrangement being such that, in use, in a first rotary position of the control member, air and spraying material are fed to the exit chamber, in a second rotary position the air, solvent liquid and material passages are closed off by the control member, and in a third position only solvent liquid is fed to the exit chamber.

Such a spray gun is particularly suitable for combination with a rotary actuator, and when so combined can be remotely operated and controlled. The invention includes such a combination.

A preferred spray gun according to the invention includes features whereby a water or other solvent wash mode can be selected.

It will be appreciated that when spraying materials such as cementitious mixes, it will be desirable on many occasions to wash out the gun to avoid the sprayed material harden ing within the gun. In conventional designs of spray gun this is often difficult. For this pur pose, a preferred spray gun according to the invention has a body with a third laterallyextending passage, intended for the water or the solvent and leading to the bore, and the rotatable control member includes a third port which in a particular position of the control member communicates with the third passage so permitting a solvent liquid supplied via the third passage to flow through the control member and to the nozzle orifice, so cleaning out the interior working parts of the gun.

Further features of the invention will be understood from the following description of an illustrative example, given with reference to the accompanying drawings in which: Figure 1 is a vertical axial section through a spray gun according to the invention showing the parts in an "on" mode; Figure 2 is a diagrammatic plan, showing three possible positions of an operating lever of the gun; and Figures 3A-C, 4A-C and 5A-C are diagrammatic cross sections taken looking down and at three spaced horizontal planes A, B and C, Fig. 3 showing the parts in the "on" mode, Fig. 4 showing the parts in the "off" mode and Fig. 5 showing the parts in the "Wash" mode.

The illustrated spray gun includes a body 10 which may be made in two mating halves connected by bolts 1 2. The body has a lateral air feed passage 14, a lateral liquid solvent feed passage 1 6 and a lateral spraying material feed passage 1 8. All of these lead from suitable connections or tappings at the exterior of the body to a central circular-section bore or channel 20 defined in the body. The water fitting at the outer end of passage 1 6 is not shown. The bore in the body houses a rotatable control member or spool 22. In the lower part of the channel 20 a nozzle 24 is threadedly secured as seen at 26. A nozzle cap 28 is secured over the end of the nozzle 24 by a nozzle sleeve 30.The cap 30 and nozzle 24 have registering orifices and the latter orifice communicates with an internal channel 32 in the member 22.

The control member 22 projects out of the top of the body 10 and carries a control lever or handle 34.

A gallery or channel 40 is provided in the bodty 10 and in the view of Fig. 1, this is located behind the control member 22. It connects via ports 42 (Fig. 3A) and 44 (Fig.

3B) respectively with the channel 20 and its downstream end 46 opens into an annular chamber 48 bounded by the radially outer wall of the nozzle 24, the lower end 50 of the body 10, the nozzle cap 28, and the sleeve 30. O-rings are provided as indicated to seal the various parts and to prevent premature or undesired mingling of the air, liquid and material fed via the passages 14, 16 and 18.

A spring-biassed detent ball 60 engages in a corresponding recess in the member 22 in the "on" position thereof, as seen at the top left-hand part of Fig. 1. A cap 62 is threaded onto the top part of the body 10 and the member 22 has a radial part-circumferential projection 64 which can engage with a stop pin 66. This limits the possible rotary movement of the control member 22. As seen in Figs. 3, 4 and 5, the movement is limited to 1805.

Referring now to Figs. 3-5. Fig. 3 shows the gun in the "on" position and corresponds to Fig. 1. The water passage 1 6 is blocked off by the spool 22, and the air passage 1 4 is connected by port 70 (Fig. 3) with the gallery passage 40. This allows the compressed air to pass to the annular exit chamber 48. The material passage 1 8 is connected by the port 72 in the spool 22 with the bore 32 and hence with the nozzle orifice 49. Thus compressed air is delivered to the chamber 48 and material to be sprayed is entrained therewith and sprayed out of the orifice 49 in the nozzle cap 28.

Fig. 4 shows the gun in the "off" position and it will be seen that the spool 22 blocks off all 3 passages 14, 16, 18.

Fig. 5 shows the gun in the "solvent wash" mode. The spool 22 blocks off the air and material passages 14 and 1 8 but its port 74 (Fig. 5A) connectes the water passage 1 6 with the gallery passage 40, so allowing feed of washing water or other solvent to clear out any undesired material in the region of the exit chamber 48 and the nozzle cap 28.

If it is desired to produce a smaller, simpler and less expensive gun, it is possible to dispense with the wash feature. That is to say, one may omit the water inlet fitting on the body, the passage 16, and the port 74, and the position of the stops on the rim 64 would be altered to allow two limit positions separated by a rotation of, for example, 90 . The resulting spray gun would have the advantage of the possibility of remote actuation and would still include the advantageous feature of a direct and readily-controlled feed of the compressed air to the exit chamber 48 via the gallery passage 40. Such a gun can be readily dissembled if desired merely by undoing the bolts 1 2 holding the two body parts together.

The design of the gun shown, with or without the solvent wash feature, has the advantage that a slim construction can be adopted, due to the fact that the longitudinal extent of the control member is arranged generally parallel to the general direction of travel of the air and the spray material from the fittings on the body to the nozzle cap orifice.

In an advantageous embodiment of the invention, not illustrated, the bore 20 in the body 10 may be provided with a sleeve or liner of hard material, for example stainless steel. This has ports (i.e. holes) in registry with the passageways 14, 16 and 18. The spool 22 then rotates within the liner. The liner and the surrounding body have respective means to secure the liner against rotation relative to the body. Such means may be constituted by a key on the exterior of the liner and a keyway in the body 10. The principal advantage of this construction is that the body may then be made of a softer, lighter and less expensive material, for example aluminium or aluminium alloy, or synthetic plastics, and the liner may be readily replaced if it wears.

In another advantageous embodiment, also not illustrated, and which may be utilised with or without the liner arrangement referred to above, a different construction of nozzle and cap is adopted. The nozzle 24 may be integral with or secured to the spool 20, and its inclined lower surface facing the inclined inner surface of the cap 28 may have a series of generally radial slots around the periphery.

These slots provide a path for the air or solvent liquid from the annular chamber 48 to the exit orifice within the cap 28, even though the nozzle 24 is in tight engagement with the cap 28 (note that this is not illustrated in Fig.

1). A compression spring may be provided to bear axially in the spool 20 to push the nozzle 24 axially downward into engagement with the cap 28, if desired.

In an alternative arrangement, the cap 28 and sleeve 30, instead of being two separate parts as illustrated, may be secured firmly together or made in one piece. The inner cylindrical surface of the sleeve 30 may be threaded, and a corresponding thread provided in the adjacent external surface of the body 10. The spool 20 and nozzle 24 are fixed axially in the bore, but free to rotate therein. Then, by relatively rotating the sleeve 30 relative to the body 10, the cap 28 sleeve 30 can be moved axially towards or away from the end of the nozzle 24. In this way, the path for air can be enlarged or made smaller, and this gives the gun the adjustability to be able to deal with the spraying of highly viscous materials. It will be understood that by unscrewing the sleeve 30 in such an arrangement, the cross-section of the air path to the exit orifice is increased as the cap 28 moves away from the confronting end of the nozzle 24 and this allows an improvement in the atomisation of viscous materials to be achieved.

In the arrangement just described, the end of the nozzle 24 need not be slotted. In such a case, the air or solvent liquid passes through an annular space defined between the inclined annular face of the nozzle 24 and the confronting inclined face of the cap 28. The threaded connection of the sleeve 30 to the body 10 may be, but need not be, such that this annular space is closed, due to the faces being in contact, when the sleeve 30 is fully screwed up onto the gun body 10.

Claims (11)

1. A spray gun having a body with a bore therethrough and laterally-extending passages which connect the bore with respective tapp ings or fittings on the exterior of the body, a rotatable control member located in the bore, and ports in the control member which can connect passages selected according to the rotary position of the control member with a gallery passage in the body leading to a nozzle orifice of the gun.

2. A spray gun which has a body with passages for air, solvent liquid, and the mate rial to sprayed all leading to a bore in the body within which is located a rotatable con trol member, the body having a longitudinally extending further passage connected to the bore and to an exit chamber adjacent to a nozzle of the gun, and the control member having respective ports for co-operation with rhe respective passages in the body, the ar rangement being such that, in use in a first rotary position of the control member, air and spraying material are fed to the exit chamber, in a second rotary position the air, solvent liquid and material passages are closed off by the control member, and in a third position only sdlvent liquid is fed to the exit chamber.

3. A spray gun according to claim 1 or 2 in combination with a rotary actuator which is arranged to rotate the control member a se lected amount.

4. A combination according to claim 3 in which the rotary actuator is on the gun and is operated and controlled from a position re mote from the gun.

5. A spray according to claim 1 or 2 in which the body is made in two mating por tions and can be split in a medial plane which passes through the axis of the bore.

6. A spray gun according to claim 1 in which the rotary control member is located axially adjacent to a nozzle having an axial passageway therethrough.

7. A spray gun according to claim 6 in which the nozzle is screwthreaded in the body and the control member can rotate relative thereto.

8. A spray gun according to claim 6 in which the nozzle is secured to the control member for rotation therewith.

9. A spray gun according to claim 6, 7 or 8 8 in which the nozzle has a lower annular surface inclined to the bore axis, which sur face is disposed in confronting relationship with an inclined annular surface on the inter ior of a nozzle cap.

10. A spray gun according to claim 9 which the nozzle cap is provided on the body and has the nozzle orifice centrally located therein.

11. A gun according to claim 10 in which I the cap is connected to the body by a sleeve screw-threaded onto the body.

1 2. A gun according to claim 10 in which the cap is integral with a sleeve which is axially adjustable relative to the body so that the nozzle-cap spacing can be varied.

1 3. A spray gun substantially as herein described with reference to and as illustrated in the accompanying drawings.