US 3743189 A
A mechanical break-up spray nozzle comprises two members which define between them, by means of a channel in at least one of the members, a passage having one end closed and its opposite end communicating with an inlet cavity, an outlet orifice of the nozzle opening into the passage intermediate its ends and the cross-sectional dimensions of the passage being small in relation to those of the inlet cavity. A nozzle member is also provided which incorporates the inlet cavity, the groove and also the outlet orifice.
Description (OCR text may contain errors)
United States Patent 1191 1111 3,743,189 Macquire-Cooper July 3, 1973  NOZZLES 2,789,012 4/1957 Bretz, Jr 239/337 ux  Inventor: Richard Terence Macquire-Cooper, FOREIGN PATENTS OR APPLICATIONS Navro House Helens Avenue 1,507,805 12/1967 France 239/337 Benson, England 848,998 9/1960 Great Britain. 239/573 Filed: Aug. 16, 1971 Appl. No.: 171,966
Foreign Application Priority Data Aug. 17, 1970 Great Britain 39,601/70 US. Cl 239/579, 239/597, 239/397 Int. Cl B05b l/04 Field of Search 239/579, 573, 337,
References Cited UNITED STATES PATENTS 6/1961 Abplanalp et al. 239/573 X 5/1967 Cooprider 4/1963 Abplanalp et al. 11/1964 Remane 239/579 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-John J. Love Att0rney-EriC H. Waters, .1. Harold Nissen et al.
 ABSTRACT A mechanical break-up spray nozzle comprises two members which define between them, by means of a channel in at least one of the members, a passage having one end closed and its opposite end communicating with an inlet cavity, an outlet orifice of the nozzle opening into the passage intermediate its ends and the crosssectional dimensions of the passage being small in relation to those of the inlet cavity. A nozzle member is also provided which incorporates the inlet cavity, the groove and also the outlet orifice.
20 Claims, 7 Drawing Figures Patented July 3, 1973 2 Shuts-Shut 1' NOZZLES BACKGROUND OF THE INVENTION This invention relates to mechanical break-up spray nozzles for breaking up a stream of fluid into a spray of fine particles.
There is a considerable commercial need for such nozzles in the aerosol field because, as opposed to other forms of nozzle, they require only a small proportion of low boiling point liquid or dissolved gas in the formulation to be sprayed. High pressures of such liquid or gas are required with other forms of nozzle for atomization.
One form of mechanical break-up nozzle relies on the turbulence produced by a swirl chamber to which the formulation is fed, there being an outlet orifice in one face of the swirl chamber. However, in view of the form of the swirl chamber and the approximately tangential form of the inlet provided to the swirl chamber from an inlet cavity, the nozzle is relatively costly to make by virtue of the complex moulding forms required for the pieces of which the nozzle is composed.
Another form of mechanical break-up nozzle utilizes impinging jets of the formulation. This nozzle thus requires a plurality of fine passages to form these jets, the passages essentially being at angles to one another. Clearly, the provision of such angled, fine, passages causes moulding difficulties and also makes it difficult to achieve consistent spray characteristics in mass production.
An object of the present invention is to provide a nozzle which can be moulded more easily and economically in large numbers, e.g., by injection moulding, and having predictable spray characteristics.
SUMMARY OF INVENTION According to one aspect of the present invention there is provided a nozzle having an inlet cavity to receive fluid to be sprayed and an outlet orifice, characterized in that the nozzle comprises two members a first of which contains a groove and the second member abutting the first member to close said groove so as to form an elongate passage having one end closed and communicating with said inlet cavity at a region spaced from said one end, and said passage throughout its extent from said region to said one end being substantially non-divergent with a cross-sectional area the dimensions of which are small in relation to said extent and in relation to cross-sectional dimensions of said cavity; and portions of said nozzle defining said orifice with a slit-form opening into said passage between said one end and said region and with opposed, outwardly diverging, surfaces extending from respective major surfaces of said opening.
It will be apparent that said first member may be formed as a nozzle member, thereby including said cavity, the orifice and the groove. An additional member may then be inserted into the nozzle member to closeoff said groove to define said passage.
Thus, according to a second aspect of the invention, there is provided a nozzle member having an inlet cavity and an outlet orifice, characterized in that the member comprises a groove in the wall of the cavity, intended passage closed at one end and opening into said cavity at a region spaced from said one end when a further member is inserted in said cavity to seal along edges of said groove, and said groove throughout its extent from said region to said one end being substantially non-divergent with a cross-sectional area the dimensions of which are small in relation to said extent and to cross-sectional dimensions of said cavity; and said orifice opening into said groove between said one end and said region by way of a slit-form opening from the major surfaces of which extend outwardly diverging surfaces of the orifice.
In one form of nozzle member, the groove may be defined by a thin curved wall which stands out from an external surface of the nozzle member.
The orifice may with advantage be disposed at a point substantially half-way along said groove or passage and there are considerable advantages in the orifice being substantially of wedge or V-shape, according to the spray pattern required. The nozzle will produce spray patterns which bear a relationship in their angle of efflux, thickness and particle size according to the cross-sectional dimensions and shape of the groove or passage. Different mass flow characteristics may be produced by design of the orifice and the groove or passage. If the orifice is of V-shape and one of the sides of the V is formed with a concave curve, the flow rates from the nozzle would tend towards a constant mass flow pattern. If the groove or passage takes a shape other than circular, then a wide range of different mass flow characteristics may be induced. For example, if a kidney or bean shaped passage is used with the lobes of the bean disposed towards the orifice, a constant mass flow spray pattern can be produced. Similarly, the passage may be generally of crescent moon shape with two lobes at its internally concave side from which the orifice extends. Various shapes of groove or passage may be used in order to determine the spray pattern required and the use of this single parameter in the design of a range of nozzles of otherwise common configuration will allow a wide range of different spray pattern producing nozzles to be formed at low cost.
In addition, it is to be noted that the length of the groove or passage affects the particle size in the spray produced.
With advantage, the orifice from which the spray emerges may be formed in a recess set into the body of the nozzle, said recess having the afore-mentioned curved wall defining part of the passage and standing out from the recess in circular or other shaped section, the orifice being disposed so that the spray produced by the nozzle does not impinge upon the exterior walls of the nozzle or recess.
In one embodiment of the invention in which the orifice is of wedge shape, one side of the wedge extends substantially at right angles to the axis of the fine bore passage or groove within the nozzle, whilst the direction of the spray is a function of the angle at which the other side of the orifice is disposed.
A very simple and effective mechanical break-up spray nozzle may be formed in accordance with the invention by utilizing one wall of an aerosol valve stem or like component as one of the defining walls of the passage of the nozzle. Thus, if said groove engages against the wall of the valve stem, or against another wall in the nozzle body, so that the groove is closed off except at one end, the resulting passage will continue to a blind end spaced from the position of the orifice. The passage thus formed by closing off the groove within the nozzle may be fed with fluid under pressure from the valve stem by allowing an expansion space in the top of the nozzle body to connect with the passage so that the fluid passing along the valve stem will reverse its direction to pass down into the fine bore passage, from which it will be expelled through the orifice. The groove in such a nozzle, where the nozzle is produced by injection moulding of a suitable thermoplastics resin, may be formed by providing a core, to define the inlet cavity, having a projection to define the groove, the core and projection being pulled out together from the nozzle when the plastic forming the nozzle is still warm from the moulding process. Thus, according to this embodiment of the invention, the fine bore passage is formed by first forming an open-sided channel, groove or slot in the main body of the nozzle,
or in a component assembled in such a body, which component may be a simple plug assembled into the body.
Alternatively, the groove may be formed in an exterior surface of a tubular member mounted in sealing engagement with the nozzle body and acting as a feed passage for fluid under pressure. In such a case, the tubular member may be provided with a plurality of such open channels, which may be of different crosssectional areas and/or lengths. If the tubular member and nozzle body are then relatively rotated, different spray characteristics can be selected by a selection of different ones of said channels. 7
In another alternative, the fine bore passage may be defined by a nozzle body and a plug, other than a valve stem, fitted into the nozzle body, either the plug or the nozzle body containing the channel.
The mechanism of spray production in the nozzle according to the invention is complex, but experiments suggest that turbulence is induced by the closed-off end of the fine bore passage, these turbulent conditions extending to the orifice. These experiments show that the distance of the orifice from the closed-off end of the fine bore passage has an important influence upon the size of particles produced. Moreover, the crosssectional dimensions of the passage serve to determine both the size of the particles produced and the flow rate through the nozzle. The higher the pressure used with this nozzle and the smaller the fine bore passage, the smaller will be the particles produced by the system. It is also found that a wedge-like slot orifice opening into the fine bore passage plays an important part in determining the direction and mass flow characteristics of the fan-shaped spray that such a slot orifice produces. Should the slot only extend over less than half the perimeter of the passage, then relatively triangular spray patterns are normally produced. With greater slot extents, wider angles of efflux are produced, together with a three-peak spray distribution. To obtain a constant mass flow spray pattern, experiments indicate that the small bore passage should with advantage have a double elliptical section, though other shapes mentioned above can produce a similar performance.
D ESCRIPTION OF DRAWINGS For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:
FIG. 1 is a front view of a first embodiment of nozzle;
FIG. 2 is a cross-section of the nozzle of FIG. 1, shown engaged with the stem of a discharge control mechanism;
FIG. 3 is a cross-section on the line III-III of FIG. 2;
FIG. 4 is a cross-section corresponding to that of FIG. 2 of an additional embodiment of nozzle;
FIG. 5 is a cross-section of a third embodiment of nozzle;
FIG. 6 shows a modification to the third embodiment of nozzle; and
FIG. 7 is a cross-section of a fifth embodiment of nozzle.
FIGS. 1 to 3 show a first embodiment of nozzle comprising an injection moulded nozzle body 1 in which is engaged a valve stem 2 having a feed passage 3. The nozzle body 1 is formed with an inlet cavity 4 in which the valve stem 2 is inserted, the wall of the inlet cavity 4 containing a fine bore groove 5 which, as seen in FIG. 2, is sealed along most of its edges by the engagement between the nozzle body 1 and the valve stem 2. In this embodiment the cross-sectional dimensions of the groove 5 are small in relation to those of the inlet cavity, the groove having a radius of 0.014 inches and the inlet cavity 4 having a radius of 0.075 inches. In general, the cross-sectional dimensions of the groove will normally be less than 0.050 inches, and preferably in the range from 0.010 to 0.050 inches, whilst the ratio of cross-sectional dimensions of the groove 5 and the inlet cavity 4 will normally be in the range between 1:3 and 1:20.
It will be seen that the passage defined by the groove 5 and the valve stem 2 connects with the internal bore 3 of the valve stem by a passage or area 6. An internal surface 7 of the nozzle body 1 provides a stop for the valve stem 2 to ensure that the passage 6 is defined between the end of the inlet cavity 4 and the valve stem 2. 1
The external face of the nozzle is formed with a recess 8 into which opens an orifice 9 in the form of a wedge-shaped slot. It will be seen that the lower face 10 of the slot extends substantially at right angles to the axis of the groove 5, whilst the upper face 11 determines the direction of the fan-shaped spray produced.
It is also to be noted that the groove 5 is defined by a thin wall 12 which forms a part-circular rib at the base of the recess 8. This rib enables the slot 9 to extend for a desired extent around the circumference of the groove 5, in the present case by about This embodiment, forming a fine bore passage of crescent shape in cross-section in combination with a wedge-shaped orifice 9 with an opening angle of about 30, produces a fan-shaped spray with a parabolic mass flow pattern.
It will be seen from FIG. 2 that the lower end of the groove 5 is closed by material of the nozzle body I itself. Thus, the groove may be formed by a projection of a core which defines the inlet cavity 4, the projection and core being removed whilst the material of the body 1 is still soft.
However, the end wall of the fine bore passage need not be defined by the nozzle body 1, but could instead be defined by the valve stem 2, as is illustrated in FIG. 4. In this case, the inlet cavity 4 is recessed to receive a shoulder 13 of the valve stem, this shoulder 13 providing an end wall for the groove 5 in the completed assembly. In other respects, the embodiment of FIG. 4 may be the same as that of FIGS. 1 to 3.
FIG. 5 shows a third embodiment similar to the preceding embodiments except that the groove 5 is in this case formed in the moulded valve stem 2, whilst there is no groove in the circularly cylindrical wall of the inlet cavity 4.
FIG. 6 shows a modification of FIG. 5, wherein the valve stem 2 contains a plurality of grooves 5. By rotation of the nozzle body 1 on the valve stem 2, any one of the grooves 5 may be placed in communication with the orifice S to select different spray characteristics. For this purpose, the channels 5 in the valve stem 2 have a plurality of different cross-sectional shapes and dimensions and also different lengths.
FIG. 7 shows an additional method of producing the fine bore passage by forming an open-ended groove 5 at the surface of a plug 14 which is sealed in a cavity in the nozzle body 1, so that this plug 14 and the nozzle body 1 together define the required fine bore passage and also the inlet cavity 4. It is also to be noted that the plug 14 has a projection 15 acting as a stop for the valve stem 2 whereby an entry passage 16 for the fine bore passage is defined between the plug 14 and the end of the valve stem 2.
Preferably, in any embodiment, the slot orifice 9 extends over no more than five twelfths of the circumference of the passage.
Also, it is to be noted that the fine bore passage may be defined by grooves in both of the two cooperating members 1 and 2 or 1 and 14. Moreover, more than one orifice may be provided opening into the fine bore passage. In addition, the inlet cavity may communicate with the passage by way of a slot at the inner end of the valve stem or fluid feed member 2.
1. In a mechanical break-up spray nozzle comprising material defining an inlet cavity and an outlet orifice, the improvement which comprises: a first member defining a groove into which said orifice opens intermediate the ends of the groove; a second member engaged with said first member to seal along edge portions of said groove so as to define with said first member an elongate passage closed at one end and communicating with said inlet cavity at a region spaced from said one end, and said passage throughout its extent from said region to said one end being substantially nondivergent with a cross-sectional area the dimensions of which are small in relation to said extent and in relation to cross-sectional dimensions of said cavity; and portions of said nozzle defining said orifice with a slit-form opening into said passage between said one end and said region and with opposed, outwardly diverging, surfaces extending from respective major surfaces of said opening.
2. A nozzle as claimed in claim 1, wherein one of said members is hollow and the other of said members is engaged within said one member.
3. A nozzle as claimed in claim 2, wherein said first member is said other member and said second member defines said orifice.
4. A nozzle as claimed in claim 3, wherein said first member defines a plurality of different grooves and is rotatable relative to the second member to place said orifice in communication with successive ones of said grooves.
5. A nozzle as claimed in claim 3, wherein said second member defines a through hole closed at one end by said first member. 1
6. A nozzle as claimed in claim 5, wherein said first member has a projection for limiting the insertion into said hole of a fluid feed tube to maintain a gap between said first member and said tube to provide communication between said passage and the interior of said tube.
7. A nozzle as claimed in claim 3, wherein said first member is the valve stem of a discharge control valve.
8. A nozzle as claimed in claim 2, wherein the first member is said one member and defines said orifice.
9. A nozzle as claimed in claim 8, wherein a projecting, curved, wall portion of said first member defines said groove.
10. A nozzle as claimed in claim 8, wherein the second member contains a feed chamber communicating with said passage via a substantially U-shaped flow path defined in said nozzle so that the directions of flow in said chamber and said passage are substantially opposite to one another.
11. A nozzle as claimed in claim 1, wherein a portion of said first member defines an end wall of said groove at said one end of said passage.
12. A nozzle as claimed in claim 1, wherein said second member defines an end wall of said passage at said one end of said passage.
13. A nozzle as claimed in claim 1, wherein said opening extends over no more than five twelfths of the circumference of said passage.
14. A nozzle as claimed in claim 1, wherein the maximum cross-sectional dimension of said passage is 0.050 inches.
15. A nozzle as claimed in claim 1, wherein the ratio of maximum cross-sectional dimensions of said cavity and said passage is in the range from 3:1 to 20:1.
16. A nozzle as claimed in claim 1, wherein the passage has an elongated cross-sectional form the length direction of which extends at an angle to the direction at right angles to the axis of said passage through said orifice.
17. A nozzle as claimed in claim 1, wherein said nozzle is operatively engaged with a pressurized container for dispensing formulations under pressure.
18. A nozzle as claimed in claim 1, wherein said two opposed surfaces diverge towards the outside of said nozzle at different angles to the direction of said extent of said passage past said opening.
19. A nozzle as claimed in claim 18, wherein one of said surfaces is substantially at right angles to said extent of said passage past said opening.
20. A nozzle as claimed in claim 19, wherein said one surface is nearer said one end of said passage than the other of said surfaces.
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