GB2108009A - A fluid pressure jet device and manifold therefor - Google Patents

Abstract

A fluid pressure jet device for dispensing gas or liquid or a mixture of both, e.g. for drying or washing operations, and for incorporation into a pressure spray gun (11), basically comprises a manifold (28) having inlet unions (17, 19) for gas and liquid, e.g. air and water, ducts (26; 33), and a lance (40) incorporating a nozzle (42); the lance (14) comprising two coaxial tubes (15, 16) the inner (16) of which communicates with the gas passage (26) within the manifold and the outer (15) of which communicates with a liquid passage (33) a part of which annularly surrounds the projecting inner portion of the inner tube (16). The inner tube (16) is shorter than the outer tube (15) and both terminate in respective nozzles (36, 42) allowing gas pressure to be used for driving the liquid at a greater speed than that at which it is supplied through the liquid passage (33) in the manifold. A further manifold (18) can be used to feed detergent into the liquid stream. <IMAGE>

Description

SPECIFICATION A fluid pressure jet device and manifold therefor The present invention relates to a fluid pressure jet device suitable for spraying gas or liquid or a mixture of both, and to a manifold for such a device. In the following Specification such a device will for convenience be referred to as a "pressure gun".

Such pressure guns are known, in which liquid (usually water) and a gas (usually air) are supplied under pressure to be discharged through a nozzle for example for washing surfaces. The compressed air accelerates the water driving it from the nozzle at high velocity thereby considerably increasing the cleaning effect which can be obtained. By varying the flow rate of the air and water various different cleaning effects can be obtained ranging from straight forward supply of water for wetting the item to be washed, to supply of just air for drying.

Known pressure guns also incorporate a further feature in that a chemical such as detergent may be introduced into the water through a further inlet, and in one known pressure jet device a canister of liquid detergent is mountable on the device itself for this purpose.

The present invention seeks to provide a fluid pressure jet device for spraying gas or liquid or a mixture of both which is of a simpler and more compact construction than known such devices, and which has technical features which allow disadvantages of the prior art device to be overcome. One such disadvantage is the excess quantity of detergent used, and in the present invention arrangement is made for a more controlled and controllable use of detergent so that only a quantity required for a given purpose is dispensed where in the prior art device an excess quantity is dispensed, and consequently wasted, since there is no provision in the prior art for lowvolume dispensing.

In one aspect, therefore, the present invention provides a fluid pressure jet device for spraying gas or liquid or a mixture of both, comprising a manifold having inlet unions for gas and liquid ducts, and a lance incorporating a nozzle, in which the lance comprises two coaxial tubes the inner of which passes through or communicates with a duct which passes through the manifold to the gas inlet union, and the outer of which communicates with a passage a part of which surrounds the inner tube or duct within the manifold and leads to the liquid union.

In such a device the manifold is at the same time extremely compact and effective in introducing the liquid and gas which, commonly, would be water and air, by providing suitable nozzles at the outlets of the lance tubes. For this purpose the inner lance tube preferably terminates in a nozzle and is shorter than the outer lance tube which, itself, terminates in a nozzle. The nozzle of the inner tube is thus positioned within the outer lance tube and is preferably held centralised therein by means of a suitable spacer or perforated washer. The nozzle on the outer tube may be axially adjustable with respect to the inner nozzle in order to vary the jet parameters in use of the gun.

In a preferred embodiment of the invention the manifold includes at least one further passage communicating with the liquid passage between the inlet union thereof and the point at which it is traversed by the gas tube, the said further passage having an inlet union for connection to a further liquid supply conduit.

The unions for the liquid passage, the gas passage and the further liquid passage are preferably arranged in a straight line on one face of the manifold. This simplifies connection and facilitates use of the device. In such an arrangement the lance tubing preferably projects from the face of the manifold opposite that on which the pipe unions are carried. The manifold and part of the lance is preferably surrounded by a casing incorporating a handle for use in directing the jet of gas and/or liquid in any required direction.

The liquid and/or the gas passage within the manifold preferably incorporates a unidirectional valve for preventing reverse flow of the liquid or gas. This is particularly important when the liquid is water drawn from a mains supply since the supply must not be contaminated by, for example, detergent or other chemical drawn into the manifold during normal use when the conditions vary, and for example, the gas pressure is increased. Such an increase in gas pressure may occur, for example, when it is desired to use the lance for drying, and the relative pressures will change as the water is turned off, or the gas pressure may be turned up by operation of a suitably positioned control valve in order to increase the velocity of the water jet without changing the rate of supply.Any surge which is experienced during the changing conditions may result in a back pressure which, since the water valve is at least partly open during such conditions, could result in back flow at least temporarily.

The or each manifold union preferably has a control valve for exercising control on the rate of flow of fluid therethrough into the associated passage in the manifold.

The liquid passage is preferably so shaped that, at least for certain flow rates, the liquid flowing therethrough experiences a fali in pressure between the inlet union and the outlet to the lance when there is gas flowing at a certain minimum in the gas passage, and the said further liquid passage opens into the said liquid passage in such a way, in use of the gun, liquid is drawn through the said further passage into the said liquid passage by the pressure differential between the said low pressure region and atmospheric pressure.

In another aspect the present invention provides a manifold for a liquid spray gun, having a liquid inlet union communicating with a liquid passage leading through the manifold to a liquid outlet, a gas inlet union communicating with a gas passage leading through the manifold to a gas outlet, and a further liquid inlet union communicating with a further liquid passage which leads into the said liquid passage at a point where, at least under certain flow conditions, the liquid flowing therethrough experiences a drop in pressure, such that in these conditions further liquid is drawn into the said main liquid passage.

The present invention also comprehends a manifold for a fluid pressure jet device, in which a gas duct leading from a gas inlet to an outlet is surrounded by a main liquid duct leading from an inlet to a gas/liquid mixing nozzle, therebeing at least one further passage in the manifold leading into the said main liquid duct.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of a fluid pressure jet device constructed and arranged to operate in accordance with the principles of the present invention; and Figure 2 is a sectional view, on an enlarged scale, of the manifold and jet nozzle of the embodiment illustrated in Figure 1.

Referring now to the drawings the embodiment illustrated comprises a casing, generally indicated 11 having a body portion 12 of elongate generally rectangular form from one end of which projects a boss 13 from which extends a lance 14 comprising, as will be seen in Figure 2, an outer lance tube 1 5 and an inner lance tube 1 6.

At the opposite end of the body 12 from the lance-support boss 1 3 there are three connector unions 17, 1 8, 19, each having a hexagonal nut which assists in securing a generally rectangular manifold 20 to the interior of the casing body 1 2.

A loop type handle generally indicated 21 is integrally formed with the body 1 2 and comprises a generally orthogonal front strut 21 a (orthogonal, that is, to the general axis of the body 12) an inclined rear strut 22 and a parallel loop arm 23 which joins the front and rear struts 21, 22 and lies generally parallel to the axis of the body 12 but spaced therefrom by a distance convenient for permitting an operator to grasp the handle conveniently and easily. The inner faces, that is the faces directed inwardly of the loop 21, of the inclined rear strut 22 and the parallel loop arm 23 are provided with finger grips in the form of a plurality of transverse corrugations or indentations 24, 25 respectively to facilitate secure gripping of the handle by these limbs.The body 12 and loop handle 21 are integrally formed as two half-shells secured together by a number of screws (not shown) or bolts housed in moulded recesses and engaging moulded bosses or studs within the casing.

The manifold 20 is formed as a substantially rectangular block having a plurality of drillings therein comprising a first drilling 26 which passes right through the body 20 from a first end face 27 to a second end face 28 and which is counter bored by an enlarged coaxial drilling 29 which has a threaded opening 30 into the face 28. The end of the narrower portion 26 of the first drilling adjacent the larger portion 29 is threaded at 31 over a portion of its length, and receives the externally threaded end of the inner tube 1 6 of the lance 14.

A second passage within the manifold body 20 is formed by two perpendicular drillings 32 and 33. The first of these, the drilling 32 extends parallel to the first drilling 26 from the face 27 inwardly of the body, but does not extend as far as the face 28. The second arm 33 of the second drilling extends orthogonally with respect to the first arm 32 from an upper face 34 of the manifold body 20 and intersects both the first arm 32 and the larger section 29 of the counter bored first drilling. A blanking plug 35 closes the mouth of the drilling 33 in the face 34 leaving the passage formed by the two drillings 32, 33 as an L-shape passage extending from its opening in the face 27 to the enlarged section 29 of the first drilling. The threaded opening 30 in the front face 28 of the manifold body 20 receives the end of the outer tube 1 5 of the lance.

The pipe union 1 7 is screwed into a threaded section of the passage 32 where it opens into the end face 27 of the manifold body 20, and the pipe union 1 9 likewise screws into a threaded section of the narrower part 26 of the first drilling. Both the unions 1 7 and 1 9 incorporate control valves having operating levers I 7a, 1 9a respectively which can be turned through a predetermined angle to control the opening of the associated valves between a fully open, unrestricted flow position and a fully closed position. Additionally, the union 1 7 incorporates a unidirectional valve (not illustrated) which allows flow of fluid into the manifold through the union 17, but prevents reverse flow.

The smaller union 1 8 which is located between the main unions 17 and 19 is threaded into the opening of a smaller passage 35 which extends parallel to the passages 26 and 32 and communicates with the transverse passage 33.

The union 1 8 incorporates a unidirectional valve allowing fluid flow from the union 18 into the transverse passage 33, but preventing reverse flow.

The union 1 9 is adapted by its size for connection to a compressed air line (not illustrated) and compressed air fed thereto passes through a valve, having an operative control lever 1 9a into the passage 26 from where it passes straight through the manifold 20 into the interior of the inner lance tube 1 6.

At the end of the inner lance tube 1 6 remote from the manifold 20 there is positioned a nozzle 36 screwed into the end of the inner lance tube 1 6 and held spaced in the centre of the outer lance tube 1 5 by means of a perforated spacing washer 37 which is of the same outer diameter as the outer diameter of the outer lance tube 1 5. Over this washer 37 is fitted an outer sleeve 39 which has a shoulder 40 and an axial flange portion 41 which, respectively, abut the washer 37 and overlie the end of the outer lance tube 15, being secured to the latter by adhesive or other suitable means.

The outer end of the sleeve 39 is threaded internally and receives an externally threaded nozzle element 42 the axial position of which can be adjusted by screwing it in or out from the sleeve 39 thereby adjusting the axial separation between the nozzle 36 and the nozzle 42.

The union 1 7 is adapted for connection to a water line for receiving water under pressure such as, for example, from the mains water supply and the unidirectional valve within the manifold 1 7 acts to prevent any possibility of contamination of the mains water supply by any chemicals used with the device or any contaminants which may be in the compressed air supplied to the union 19.

A smaller tube (not shown) is attached in use to the union 18 and leads to a drum or other container of liquid chemical, such as detergent or the like, to be used by the device.

In operation, when connected as indicated above, the valve 1 7a is opened to allow water to flow under pressure through the interior passages 32, 33 to the enlarged passage 29 which communicates with the annular space between the outer lance tube 1 5 and the inner lance tube 1 6 along which it travels until it passes through the apertures in the washer and the aperture in the lance nozzle 42 being ejected from the lance in a spray or jet depending on the configuration and form of the nozzle 42.If at the same time the valve 1 9a of the union 1 9 is opened compressed air enters the interior of the inner lance tube 1 6 and is ejected at high velocity through the nozzle 36 into the chamber 43 of the nozzle 42 between the washer 37 and the nozzle element 42 this causes acceleration of the water through the nozzle 42 resulting in high velocity impact of the water ejected from the lance on any target at which it is directed. With both the valves 17a. 19a fully open the pressure within the passages 32, 33, 29 is balanced. Should it be desired to dispense the detergent or other chemical from the container attached to the union 1 8 it is only necessary to close the valve 1 7a controlling the water supply until the water supply has reached a low rate of flow.The acceleration of the water due to the action of the compressed air being ejected from the nozzle 36 causes a reduction in pressure in the outer annular space between the inner lance tube 1 6 and the outer lance tube 15, which pressure drop is communicated via the passage 29 to the passage 33 within the manifold body 20. The pressure differential between atmospheric pressure and the reduced pressure in the passage 33 results in the induction of liquid detergent through the pipe union 1 8 and the passage 35.

This detergent mixes with the water flowing from the union 1 7 and is conveyed along the lance to be ejected from the nozzle 42 by the compressed air coming from the nozzle 36. Because the water flow rate is low in these conditions the quantity of detergent being dispensed can be contained to within reasonable limits, and concentration of detergent can be varied by adjusting the setting of the water flow control valve 1 7a.If this valve is completely closed whilst the valve 1 9a is open the liquid detergent will be drawn into the manifold 20 and ejected from the lance 14 as an undiluted liquid, whereas once the water flow rate has reached a critical threshold valve determined by the dimensions of the manifold and the unions there will be no pressure reduction in the passage 33, or such pressure reduction as exists will be insufficient to draw detergent in through the narrow tube attached to the manifold 1 8 and consequently only water will be ejected from the lance 14.In this way a washing sequence comprising wetting the target with clean water can be effected first by simply opening the valve 1 7a leaving the valve 1 9a closed, following which a high velocity jet of clean water may be used to dislodge particles of dirt and then, by closing the valve 1 7a in the water line progressively a quantity of detergent can be dispensed at a selected concentration, or even as a foam (depending on the chemical used as the detergent). After this, by opening the valve 1 7a fully again a high pressure jet can again be directed at the target to rinse this and further dislodge particles of dirt loosened by the detergent.

In other embodiments, now shown, more than one union such as the union 18 may be provided between the main water and air unions 17, 1 9 for allowing a number of different chemicals to be employed. In such a case the subsidiary of chemical pipe unions will need to have individual control valves of an on-off type for selecting which, or which combination, of the chemicals is to be supplied through the nozzle. The union 1 8 and any similar chemical additive unions should preferably be provided with unidirectional valves to prevent water entering through the pipe 35 into the chemical.container.

Claims (12)

1. A fluid pressure jet device for spraying gas or liquid or a mixture of both, comprising a manifold having inlet unions for gas and liquid ducts, and a lance incorporating a nozzle, in which the lance comprises two coaxial tubes the inner of which passes through or communicates with a duct which passes through the manifold to the gas inlet union, and the outer of which communicates with 3 passage a part of which surrounds the inner tube or duct within the manifold and leads to the liquid union.

2. A fluid pressure jet device as claimed in Claim 1 in which the inner lance tube terminates in a nozzle and is shorter than the outer lance tube which itself terminates in a nozzle.

3. A fluid pressure jet device as claimed in Claim 1 or Claim 2 in which the nozzle on the outer tube is axially adjustabie with respect to the inner nozzle to vary the jet parameters in use of the gun.

4. A fluid pressure jet device as claimed in any of Claims 1 to 3 in which the manifold includes at least one further passage communicating with the liquid passage between the inlet union thereof and the point at which it is traversed by the gas tube, the said further passage having an inlet union for connection to a further liquid supply conduit.

5. A fluid pressure jet device as claimed in any preceding claim in which the unions for the liquid passage, the gas passage and the further liquid passage, are arranged in a line on one face of the manifold.

6. A fluid pressure jet device as claimed in any preceding claim in which the lance tubing projects from the face of the manifold opposite that on which the pipe unions are carried.

7. A fluid pressure jet device as claimed in any preceding claim, in which the liquid and/or the gas passage within the manifold incorporates a unidirectional valve for preventing reverse flow of the liquid or gas.

8. A fluid pressure jet device as claimed in any preceding claim in which each manifold union has a control valve for exercising control on the rate of flow of fluid therethrough into the associated passage in the manifold.

9. A fluid pressure jet device as claimed in any preceding claim, in which the liquid passage is so shaped that at least for certain flow rates the liquid flowing therethrough experiences a fall in pressure between the inlet union and the outlet to the lance when there is no gas flowing in the gas passage, and the said further liquid passage opens into the said liquid passage in the said low pressure region such that, in use of the gun, liquid is drawn through the said further passage into the said liquid passage by the pressure differential between the said low pressure region and atmospheric pressure.

10. A manifold for a liquid spray gun, having a liquid inlet union communicating with a liquid passage leading through the manifold to a liquid outlet, a gas inlet union communicating with a gas passage leading through the manifold to a gas outlet, and a further liquid inlet union communicating with a further liquid passage which leads into the said liquid passage at a point where, at least under certain flow conditions, the liquid flowing therethrough experiences a drop in pressure, such that in these conditions further liquid is drawn into the said main liquid passage.

11. A manifold for a liquid spray gun substantially as hereinbefore described with reference to the accompanying drawings,

12. A pressure jet device substantially as hereinbefore described with reference to the accompanying drawings.