GB2093733A - Spraying apparatus - Google Patents

Abstract

A spraying apparatus has an inlet 2 for compressed air, an inlet 3 for water, at least one inlet 4 for a fluid additive and a discharge outlet 11. Passage means direct the flow of air, water and fluid additive from the inlets such that the flow of air is brought together with the flow of water and fluid additive and such that the latter flow is drawn into the flow of compressed air upstream of the discharge outlet. The passage means is such that the velocity of air is caused to increase where the flows are brought together and the resulting mixture has a high exit velocity from the discharge outlet. <IMAGE>

Description

SPECIFICATION Spraying apparatus The present invention relates to spraying apparatus.

The present invention includes a spraying apparatus comprising a body enclosing at least one chamber and a venturi passage in communication with the or each chamber; an inlet for supplying compressed air to said venturi passage, said air inlet including a control valve; an inlet for supplying water to the or one chamber, said water inlet including a control valve; and inlet for a fluid additive to the or another chamber; and an outlet from said venturi passage for the mixture produced therein, in use, from the selected proportions of compressed air, water and fluid additive.

In order that the invention may be well understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is an external side view of a foaming/spraying apparatus; Figure 2 is a transverse cross-section through an optional outlet attachment for the apparatus of Fig. 1; Figure 3 is a section on the line A- of Fig.

2; and Figures 4 and 5 are sketches of respective modified spraying apparatus.

The apparatus illustrated in Fig. 1 comprises a body 1 having an inlet 2 for compressed air which is illustrated here as a connector for a feed pipe from a compressed air cylinder. The body 1 also has an inlet 3 for water which is here illustrated as a connector for a hose, for example a conventional garden hose which is connectable at its other end to a tap Alternative inlets for a fluid additive are illustrated. The first fluid additive inlet 4 comprises a connector for a pipe which may lead to, for example, a tank containing a detergent which is drawn into the body by suction. The second fluid additive inlet comprises a container 5 fitted to the body 1.The container 5 has an outlet (not shown) which leads via a control valve 6 into a chamber (not shown) formed inside the body. The container 5 is provided with a cap 7 comprising a vacuum control knob. The cap may be made of brass.

The water inlet 3 supplies water through a passage within the body via a control valve 8 either to the chamber referred to above where it mixes with the fluid additive, or to a sepa- rate chamber. The valve 8 is capable of cutting off the water supply if a spray of fluid additive in air or an air only spray is required.

The valve 8 also accurately meters the proportion of water to fluid additive together with valve 6, if the fluid additive is being supplied from container 5, when, for example, a foam is required with the use of a detergent additire.

The air inlet 2 supplies compressed air through the body 1 to a venturi passage therein (not shown) which is in communication with the or each chamber. The supply of air is controlled by a valve 9 in its path. The valve 9 is also capable of cutting off the supply of air when the spray is no longer required.

A tube 10 provides an outlet from the venturi passage. The tube 10 is preferably made of a chemical resistant material to enable the use of a wide variety of fluid additives.

The end of tube 10 is provided with a discharge nozzle 11 which may be formed of machined brass.

The body of the apparatus is provided with a hand grip 112. The container 5 may also serve as an additional handle to permit accurate directional control of the spray. The provision of a long length of tubing 10 also assists in spraying smaller areas or objects whilst allowing the operator to remain at a distance.

To operate the spraying/foaming apparatus the air inlet 2 is connected to a supply of compressed air and the water inlet 3 to a water supply. If the fluid additive inlet 4 is to be used then it is also connected and/or the container 5 is filled. The control valves 6, 8 and 9 are adjusted to give the required proportions of air, water and fluid additive. The passage of the compressed air through the venturi passage causes the water and fluid additive in the or each chamber to be drawn into the reduced pressure air flow to mix therewith and produce a foam or spray which leaves the venturi passage through tube 10 to discharge nozzle 11 at a high velocity. The exit velocity of the spray may be controlled by air valve 9.The blasting effecft of the foam/spray leaving nozzle 11 is created by its high momentum due to the high velocity created in the venturi passage.

An improvement in the above-described apparatus comprises an optional outlet attachment as illustrated in Figs. 2 and 3 for maintaining the spray in a narrow jet or controlling the degree of spreading of the spray as it emerges from the nozzle. The attachment 1 2 comprises a jacket member 1 3 provided with an inlet 14 for compressed air which includes an on/off control valve 1 5.

The jacket member 1 3 surrounds the junction of outlet tube 10 from the body of the spray gun with a further outlet tube 1 6. It may be convenient to attach the jacket member 1 3 directly to the junction of the body 1 with a single outlet tube such that the valve 1 5 may readily be operated by the user of the gun.

The attachment 1 2 may be connected to outlet tube 1 0 or the body 1 by a screw thread type or quick release coupling. The supply of compressed air to jacket member 1 3 introduces a surrounding layer of compressed air around the foam/spray leaving the body 1. This layer prevents the foam/spray from spreading and losing its velocity and pressure shortly after leaving the apparatus. The jacket member and tube 16 may be formed of plastics material or metal and are preferably chemical resistant.

The described apparatus may be utilised to spray air alone, air and water, or air and a fluid additive, or a foam or spray comprising air, water and a fluid additive. Accordingly by simple adjustments of the control valves and using a detergent additive the same apparatus may be utilized for all the stages of a cleaning operation. With the use of suitable additives the apparatus may also be used to form and deliver a fire fighting foam, or spray plants with insecticide. It will be appreciated that many further uses of the apparatus are also possible.

The attachment as illustrated in Figs. 2 and 3 may also be used independently of the spray gun and be separately attached to a water supply or wet sand or other abrasive injector by means of a suitable coupling.

The apparatus shown in Fig. 4 operates in the same manner as the apparatus illustrated in Figs. 1 to 3 in that compressed air is supplied through an inlet 2 to a venturi passage in the body 1 of the apparatus. As in Figs. 1 to 3 the reference numerals 3, 4 8 and 9 designate a water inlet, an additive inlet, a water control valve and an air control valve respectively by which water and additive can be introduced into the body 1 for mixing with the compressed air as described in our earlier application. The resultant mixture issues from the apparatus via outlet tube 10.

The apparatus is in the form of a gun with the body 1 providing a hand grip 12. It will be noted that the inlets 2, 3 and 4 all enter the body 1 at the bottom of the hand grip 1 2 which facilitates handling of the gun in use when it is connected by supply lines or pipes (not shown).

Fig. 5 shows spraying apparatus in which no provision has been made for an additive.

However, it is to be understood that an additive inlet might be provided. Water and air are supplied to the apparatus via supply pipes (not shown) connected to respective connections 3 and 2 and the bottom portion 20 of body 1. A water inlet valve would be provided on the supply pipe therefor and a trigger operated valve 9 conrols the flow of air to the venturi passage of the apparatus. The outlet 21 of the apparatus comprises a nozzle arrangement which includes two relatively rotatable members which can be adjusted to completely shut off the flow of mixture from the apparatus, or to adjust this flow to a desired spay or to provide a blast force of mixture.

The apparatus is in the form of a gun and includes a hook 22 by which it can be hung when not in use.

Claims (11)

1. Spraying apparatus, comprising a body enclosing at least one chamber and a venturi passage in communication with the or each chamber; an inlet for supplying compressed air to said venturi passage, said air inlet including a control valve; and inlet for supplying water to the or one chamber, said water inlet including a control valve; an inlet for supplying a fluid additive to the or another chamber; and a discharge outlet downstream of the venturi passage for discharging a mixture of the compressed air, water and fluid additive.

2. Spraying apparatus comprising a discharge outlet, an inlet for compressed air including a control valve, an inlet for water including a control valve, an inlet for fluid additive, passage means for directing the flow of compressed air, water and fluid additive from the inlets therefor and arranged such that the flow of air is brought together with the flow, or flows, of water and fluid additive and such that the latter flow, or flows, is, or are, drawn into the flow of compressed air upstream of the discharge outlet.

3. Spraying apparatus as claimed in claim 2, wherein said passage means is such that the velocity of the air is caused to increase where the flow of air is brought together with the flow or flows of water and fluid additive.

4. Spraying apparatus as claimed in claim 2 or 3, wherein the passage means is such that the flows of water from the water inlet and fluid additive from the fluid additive inlet are brought together before being brought together with the flow of air from the compressed air inlet.

5. Spraying apparatus as claimed in any one of the preceding claims, wherein the fluid additive inlet is provided with a control valve.

6. Spraying apparatus as claimed in any one of the preceding claims, having a second fluid additive inlet for supplying a second fluid additive and passage means for bringing the flow of second fluid additive together with the flow of water, or water and first fluid additive.

7. Spaying apparatus as claimed in any one of the preceding claims, including means for selectively providing a surrounding layer of compressed air around the flow leaving the discharge outlet.

8. Spraying apparatus as claimed in claim 7 wherein said means comprises a jacket adapted to be mounted about the discharge outlet, means for providing a supply of compressed air to said jacket, and means for controlling the supply of compressed air.

9. Spraying apparatus as claimed in any one of the preceding claims, wherein said discharge outlet comprises a nozzle.

10. Spraying apparatus as claimed in claim 9, wherein said nozzle includes two relatively rotatable members relative rotation of which adjusts the flow from the nozzle.

11. Spraying apparatus substantially as herein described with reference to the accompanying drawings.