Improved blow off cap and nozzle system

Abstract

A blow off cap and nozzle system including: a spray nozzle having: a nozzle body defining an inlet and outlet; a crown detachably connected to or forming an integral part of the nozzle body; and, a shroud located about the outlet and adapted to define a cavity with an open mouth; and a cap adapted to plug the cavity and release when subjected to a discharge of liquid through the cavity, the cap having: a top adapted in use to be located proud of the open mouth of the shroud; and, an elongate body extending downwardly from the top and being adapted to snugly fit into the cavity;

Description

[0001] Improved Blow Off Cap and Nozzle System

[0002] Technical Field

[0003] The present invention relates generally to a protective cap and nozzle system for maintaining the aperture or orifice in aspirating nozzles clear of foreign matters and / or for preventing the cap from being obstructed or stuck during the ejection process. The present invention relates more specifically but not exclusively to a blow off type of protective cap which is designed to eject via thrust from a liquid stream or jet.

[0004] Background of the Invention

[0005] In some circumstances and environments, fire suppression nozzles can sit dormant in service for up to a year or more before activation. During such a dormant period, nozzles can become clogged or obstructed by foreign material, such grease particularly when combined with dust and / or dirt, oil or dead insects and their nests. A number of prior art solutions exist to prevent blockage of the nozzles from occurring. They include the application of a protection cap that ejects from a nozzle upon discharge of a high- pressure jet of water or an extinguishing agent. However, it has been found that some firefighting surfactants have some functional issues. For instance, a functional suppression foam cannot be achieved by chemical aspiration within the surfactant mixture alone. As such, a mechanical method of facilitating mixing of the surfactant with air is required to achieve a functional foam.

[0006] Previous attempts have been made to provide nozzles with a shroud for enabling the above-described mixing of the surfactant with air. These nozzles typically involves the use of a shroud (as referred to as an aspirating cone) to draw air into the nozzle fluid stream to promote a mixture of the ejected surfactant with air thereby causing aspiration. In order to prevent any blockage or obstruction, for example, a metal foil protection and blow-off system, such as that disclosed in US patent number 10569113, is used to protect the shrouded nozzle during its service life. Such a system however has a shortcoming in that the metallic foil is susceptible to corrosion issues, particularly when exposed and operating in chemically aggressive environments. In order to overcome the corrosion-related issues, attempts have been made to have the cap made out of contemporary polymer. This however gives rise to different issues. For instance, a cap made out of polymer is prone to bending or twisting to one side of the aspiration cone and thus getting stuck within the aspirating cone during ejection. This blockage would lead to a malfunction of the nozzle in that the discharge pattern of the foam is distorted or at least affected. Also, there is another shortcoming in that the foil protection system for an externally shrouded nozzle might not be best suited to the environment or application for various reasons such as cost. This is because a one-piece externally shrouded aspirating nozzle with the addition of an all-metal foil blow-off cap is a geometrically and mechanically complex assembly that may prove to be too costly for some intended applications.

[0007] It is therefore an object of the present invention to provide a blow off cap and nozzle system and a blow off cap for an aspirating spray nozzle which may overcome or at least ameliorate the above shortcomings or which may at least provide a useful choice.

[0008] Summary of the Invention

[0009] According to one aspect, there is provided herein, a blow off cap and nozzle system including: a spray nozzle having: a nozzle body defining an inlet and outlet; a crown detachably connected to or forming an integral part of the nozzle body; and, a shroud located about the outlet and adapted to define a cavity with an open mouth; and a cap adapted to plug the cavity and release when subjected to a discharge of liquid through the cavity, the cap having: a top adapted in use to be located proud of the open mouth of the shroud; and, an elongate body extending downwardly from the top and being adapted to snugly fit into the cavity; wherein the elongate body has a skirt portion adapted to engage the crown so as to releasably retain the cap within the cavity.

[0010] According to another aspect of the present invention, there is provided a blow off cap and nozzle system including: a spray nozzle having: a nozzle body defining an inlet and outlet; a crown detachably connected to or forming an integral part of the nozzle body; a shroud located about the outlet and adapted to define a cavity with an open mouth; and an elastic or at least malleable cap adapted to plug the cavity and dislodge when subjected to the thrust of longitudinally discharged liquid, the cap having: a top adapted in use to be located proud of the open mouth of the shroud; and an elongate body extending downwardly from the top and being adapted to snugly fit into the cavity; wherein the elongate body has a skirt portion adapted to engage the crown so as to releasably retain the cap within the cavity.

[0011] Preferably, the skirt portion includes latching mechanism / means adapted to engage a corresponding element of the crown so as to facilitate retention of the blow off cap within the cavity. More preferably, the elongate body is defined by a cylindrical wall, the latching mechanism being an annular barb extending inwardly from the cylindrical wall.

[0012] Preferably, the corresponding element of the crown includes a circumferential groove. More preferably, the circumferential groove is adapted in use to receive and mate with the annular barb. Most preferably, the crown includes a rim providing a circumferential shoulder.

[0013] Preferably, the cylindrical wall includes a radially thickened portion intermediate the top and the skirt portion. The thickened portion is preferred to create a step configured in use to engage the circumferential shoulder so as to facilitate placement of the cap at a pre-determined location. As such, upon insertion and placement of the cap within the cavity, the step of the thickened portion is configured and arranged to abut the circumferential shoulder which functions to prop up the blow off cap.

[0014] Preferably, the top includes a flange configured to hang over the mouth of the shroud. More preferably, the thickened portion has a length so dimensioned and designed as to provide a gap between the overhanging flange and mouth of the shroud. The gap is preferred to have a width of at least 0.5 millimetre. In a preferred embodiment, the top includes an external indent adapted to facilitate forced insertion and advancement of the cap into the cavity. Optionally, the indent is frustoconical in shape. More preferably, the top includes a thinned portion being so configured and arranged in use to cause axial bloating thereof when the cap is thrusted by a longitudinally discharged liquid. As such, radial or lateral elastic expansion of the cylindrical wall may be minimised to avoid or at least reduce the likelihood of the cap being caught or stuck during ejection of the cap.

[0015] According to one example, the cap can be formed of a resilient, flexible or malleable material such as silicone or rubber, or the like.

[0016] According to another aspect of the present invention, there is provided a blow off cap for placement within a spray nozzle having: a nozzle body defining an inlet and outlet; a crown detachably connected to or forming an integral part of the nozzle body; a shroud located about the outlet and adapted to define a cavity with an open mouth; the cap being elastically deformable or at least malleable and adapted to plug the cavity and dislodge when subjected to the thrust of longitudinally discharged liquid, the cap having: a top adapted in use to be located proud of the open mouth of the shroud; and an elongate body extending downwardly from the top and being adapted to snugly fit into the cavity; wherein the elongate body has a skirt portion adapted to engage the crown so as to releasably retain the cap within the cavity.

[0017] According to a further aspect of the present invention, there is provided a spray nozzle for detachably receiving a blow off cap, the spray nozzle including: a nozzle body defining an inlet and outlet; a crown detachably connected to or forming an integral part of the nozzle body; a shroud located about the outlet and adapted to define a cavity with an open mouth; the cap being elastically deformable or at least malleable and adapted to plug the cavity and dislodge when subjected to the thrust of longitudinally discharged liquid, the cap having: a top adapted in use to be located proud of the open mouth of the shroud; and an elongate body extending downwardly from the top and being adapted to snugly fit into the cavity and having a skirt portion; wherein the crown includes an element which corresponds with the skirt portion of the elongate body so as to releasably retain the cap within the cavity.

[0018] It will be appreciated that all features of all embodiments, examples, aspects and forms described herein can be used in any combination.

[0019] Brief Description of the Drawings

[0020] A preferred embodiment of the blow-off cap and nozzle system of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

[0021] Figure 1 is an exploded perspective view of a blow-off cap and nozzle system of the present invention;

[0022] Figure 2 is a cross sectional view of the assembled blow-off cap and nozzle system of Figure 1, illustrating the blow-off cap installed in the nozzle;

[0023] Figure 3 is a perspective view of the blow-off cap of Figure 1;

[0024] Figure 4 is cross sectional view of the blow-off cap of Figure 1; and

[0025] Figure 5 is a cross sectional view of just the nozzle of the blow-off cap and system of Figure 1 incorporating a metal foil and pintle which are used in a pre-existing design.

[0026] Detailed Description of Preferred Embodiments Referring to Figures 1 and 2, a blow off cap and nozzle system 10 is shown. The system 10 involves a spray nozzle 12 and an elastically deformable or at least malleable cap 14. The spray nozzle 12 has a nozzle body 16, a crown 18 and a shroud 20. The nozzle body 16 defines an inlet 22 and outlet 24. The inlet 22 being located at the most upstream point of the nozzle 12 receives fluid from the fire suppression line. The nozzle 12 includes a core 64 which functions to agitate the incoming fluid and promotes turbulent flow which encourages and enhances chemical and mechanical aspiration of any surfactant. The shroud 20 in the preset embodiment is in unity with the nozzle body 16 being integrated thereinto. It should however be noted that the shroud 20 may be provided as a separate piece being detachably connectable to the nozzle body 16. The shroud 20 includes one continuous or multiple separated inlets 66 for drawing air into the aspiration cone as a result of the Venturi effect where the flow of fluid through an open Venturi shroud draws in air through the inlet without requiring any additional work. The nozzle includes an orifice which is essentially created by the outlet 24. In the present embodiment, the crown 18 is threadably connected to the nozzle body 16. The shroud 20 is located about the outlet 24 and adapted to define a cavity 26 which is also known as an aspirating cone defining an aspirating zone. The shroud 20 has an open mouth 28. The elastically deformable or at least malleable cap 14 is designed and configured to plug the cavity 26 and dislodge when subjected to the thrust of longitudinally discharged liquid such as a water jet or an extinguishing agent.

[0027] Referring to Figures 3 and 4, the cap 14 has a top 30 and an elongate body 32. As best shown in Figure 2, the top 30 is configured in use to be located proud of the open mouth 28 of the shroud 20. The elongate body 32 extends downwardly from the top 30 and is adapted to snugly fit into the cavity 26. In one particular example, the elongate body 32 is shaped such that when the cap 14 is inserted into the nozzle 12, the shape of the elongate body 32 corresponds with the shape of the cavity 26 and can also be configured to mate with corresponding elements of the nozzle 12.

[0028] The elongate body 32 has a skirt portion 34 which is configured and dimensioned to engage the crown 18 so as to releasably retain the cap 14 within the cavity 26. The skirt portion 34 has latching means adapted to engage a corresponding element of the crown 18 so as to facilitate retention of the blow-off cap 14 within the cavity 26. The elongate body 32 is defined by a cylindrical wall 36. The latching means is in the form of an annular barb 38 extending inwardly from the cylindrical wall 36. The corresponding element on the nozzle 10 includes a circumferential groove 40 which is configured to receive and mate with the annular barb 38. The crown 18 also has a rim providing a circumferential shoulder 42.

[0029] Turning now to Figures 2 to 4, the cylindrical wall 36 has a radially thickened portion 44 intermediate the top 30 and the skirt portion 34. The thickened portion 44 creates a step 46 configured in use to engage the circumferential shoulder 42 so as to facilitate placement of the cap 14 at a pre-determined location. As such, upon insertion and placement of the cap 14 within the cavity 26, the step 46 of the thickened portion 44 is configured and arranged to abut the circumferential shoulder 42 which functions to prop up the blow-off cap 14.

[0030] As shown in Figures 1 to 4, the top 30 includes a flange 48 configured to hang over the mouth 28 of the shroud 20. The thickened portion 44 has a length 50 so dimensioned and designed as to provide a gap 52 between the overhanging flange 48 and mouth 28 of the shroud 20. In this particular embodiment, the gap 52 has a width of 0.5 millimetre. It should be noted that the width of the gap may vary to suit different needs and circumstances.

[0031] As best shown in Figures 1, 2 and 4, the top 30 has an external indent 54 designed and configured to facilitate forced insertion and advancement of the cap 14 into the cavity 26. The indent 54 is frustoconical in shape being adapted to facilitate the use of a finger for press-fitting the cap 14 into the cavity 26. This is generally referred to as a 'buttontype' configuration. The top 30 also has a thinned portion 56 (thinner in comparison to the sides of the cylindrical wall 36) which is so configured and arranged in use to cause axial bloating thereof when the cap 14 is thrusted by a stream or jet of longitudinally discharged liquid. As such, radial or lateral elastic expansion of the cylindrical wall 36 is minimised to avoid or at least reduce the likelihood of the cap 14 being caught or stuck during ejection. Now that a preferred embodiment has been described, it will be appreciated that the cap 14 of the present invention may be applied to both conventional and externally shrouded aspiration nozzles. The cap can be applied in a very easy and simple push-fit manner without requiring much dexterity. During installation and blow-off, it will be appreciated that the skirt portion 34 of the cap 14 is supposed to stretch and flex to a certain degree to facilitate and achieve engagement and disengagement of the annular barb 38 with the circumferential groove 40. In particular, it should be noted that the cap 14 is designed to be retained by this interlocking arrangement when the nozzle 12 is sitting dormant but the interlocking arrangement is designed to be effectively overcome by the fluid stream or jet in order to result in dislodgement and ejection of the cap 14 out of the cavity 26.

[0032] It will also be appreciated that the described embodiments / examples of the present invention may offer one or more of the following advantages:

[0033] (i) the cap is typically dimensioned so that it cannot be pushed too far into the cavity or that pushing into the cavity is limited to an extent that its function is compromised; It will be appreciated that a user does not typically need to worry about placement orientation or precision during installation of the cap;

[0034] (ii) the external diameter and axial positioning of the cap can minimise the likelihood of the cap getting any interference with or caught within the external shroud;

[0035] (iii) the flange that hangs over the mouth of shroud can also be capable of keeping both the shroud cavity and the nozzle orifice clean and clear during service;

[0036] (iv) the annular barb is typically designed and shaped such that it is not susceptible to being captured upon discharge;

[0037] (v) the overhanging flange of the top of the cap can offer enhanced protection of the end of an external aspiration shroud, specifically the delicate agitation teeth 62 (see for example, Figures 1 and 2) from being damaged which could inhibit or at least affect the efficiency and efficacy of aspiration; (vi) the cap can present an intuitive button aesthetic which encourages pressing therefore onto the nozzle as intended;

[0038] (vii) the thinned and indented portion in the top of the cap can be capable of dictating elastic deformation of the cap during blow off; this design and configuration can cause the silicone cap to deform like a balloon when the nozzle is activated, resulting in the cap first bloating at the thinnest wall section at the top rather than the sides; this can mean that the cap is less prone to expanding radially or laterally in such a way that could interfere with the shroud or get caught; and

[0039] (viii) in combination with the gap 52, the overhanging flange 48 can present a useful area where the user can peel off or apply the cap during maintenance or assembly.

[0040] It should be noted that the nozzle of the system of the present invention is typically an aspirating spray nozzle with a shroud. According to one example, the cap 14 of the system of the present invention is preferred to be made out of a low-taint, elastically deformable, malleable, flexible and fire-resistant material such as silicone. Also, a cap made out of silicone can offer the advantage of being light weight and hence easy to handle and relatively non-harmful in case it hits something or someone during ejection. Furthermore, the cap 14 has a lightweight geometry with an optimised wall thickness so as to facilitate effective and smooth cap ejection at a test-compliant blow-off pressure.

[0041] Variations and / or modifications may be made to the preferred embodiments described above without departing from the spirit or ambit of the invention. For example, the crown 18 may form an integral part of the nozzle body 16. Also, it is noteworthy that as shown in Figure 5, the nozzle 12 of the system 10 of the present invention may incorporate and accommodate a metal foil 58 and pintle 60 which are used in a preexisting design. This can offer the advantage of giving the user the options and flexibility of using either the conventional blow-off cap in the metal foil form or the cap 14 of the present invention which is made out of silicone. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. Reference to a feature disclosed herein does not mean that all embodiments must include the feature. Prior art, if any, described herein is not to be taken as an admission that the prior art forms part of the common general knowledge in any jurisdiction.

[0042] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "include" or variations such as "includes" or "including" is used in an inclusive sense, that is to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

CLAIMS1. A blow off cap and nozzle system including: a. a spray nozzle having: i. a nozzle body defining an inlet and outlet; ii. a crown detachably connected to or forming an integral part of the nozzle body; and, iii. a shroud located about the outlet and adapted to define a cavity with an open mouth; and b. a cap adapted to plug the cavity and release when subjected to a discharge of liquid through the cavity, the cap having: i. a top adapted in use to be located proud of the open mouth of the shroud; and, ii. an elongate body extending downwardly from the top and being adapted to snugly fit into the cavity; wherein the elongate body has a skirt portion adapted to engage the crown so as to releasably retain the cap within the cavity.

2. The blow off cap and nozzle system of claim 1, wherein the skirt portion includes a latching mechanism configured to engage a corresponding element of the crown to facilitate retention of the blow off cap within the cavity.

3. The blow off cap and nozzle system of claim 2, wherein the elongate body is defined by a cylindrical wall, the latching mechanism being an annular barb extending inwardly from the cylindrical wall.

4. The blow off cap and nozzle system of claim 3, wherein the corresponding element of the crown includes a circumferential groove.

5. The blow off cap and nozzle system of claim 4, wherein the circumferential groove is configured in use to receive and mate with the annular barb.

6. The blow off cap and nozzle system of claim 5, wherein the crown includes a rim providing a circumferential shoulder.

7. The blow off cap and nozzle system of claim 6, wherein the cylindrical wall includes a radially thickened portion intermediate the top and the skirt portion.

8. The blow off cap and nozzle system of claim 7, wherein the thickened portion creates a step configured in use to engage the circumferential shoulder so as to facilitate placement of the cap at a pre-determined location.

9. The blow off cap and nozzle system of claim 8, wherein the top includes a flange configured to hang over the mouth of the shroud.

10. The blow off cap and nozzle system of claim 9, wherein the thickened portion has a length so dimensioned to provide a gap between the overhanging flange and mouth of the shroud.

11. The blow off cap and nozzle system of claim 10, wherein the top includes an external indent adapted to facilitate forced insertion and advancement of the cap into the cavity.

12. The blow off cap and nozzle system of claim 11, wherein the indent is frustoconical in shape.

13. The blow off cap and nozzle system of claim 12, wherein the top includes a thinned portion being so configured and arranged in use to cause axial bloating thereof when the cap is thrusted by discharging liquid.

14. A blow off cap for placement within a spray nozzle having: a. a nozzle body defining an inlet and outlet; b. a crown detachably connected to or forming an integral part of the nozzle body; c. a shroud located about the outlet and adapted to define a cavity with an open mouth; the cap being malleable and adapted to plug the cavity and dislodge when subjected to the thrust liquid through the spray nozzle, the cap having a top adapted in use to be located proud of the open mouth of the shroud; and, an elongate body extendingdownwardly from the top and being adapted to snugly fit into the cavity; wherein the elongate body has a skirt portion adapted to engage the crown so as to releasably retain the cap within the cavity.

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