In many fluid application situations, an application device is needed capable of providing an expanded area of coverage. To expand the coverage of a sprayed fluid, a diffuser (expander) is often employed. However, for antibacterial treatment, the standard diffuser design may cause a loss of efficiency. A fluid nozzle providing optimal coverage to a surface or to provide the most effective application of a fluid is needed. Such a device could be used to optimally treat a surface rapidly that is bearing microbes yet prevent overheating or burning of the surface from heat guns or steaming devices.
The food industry requires a larger area of coverage regarding the impact of superheated steam and steam mixtures on affected surfaces. An extremely lightweight device is needed having a fluid nozzle that can disperse the superheated steam yet not lose effectiveness (superheated temperature for rapid microbial removal). Such a device could be used to quicken the pace of antibacterial cleaning. These devices may produce steam and steam mixtures that are significantly more potent than required by the FDA rule for 5 log reduction in 30 minutes.
Herein is described a diffuser attachment to a nozzle that can spread directed, effective applications of a fluid to increase the contact area of treatment and hence improve productivity and reduce human energy use. A new diffuser is proposed which converges down from the nozzle (exhaust end of the application device) but enables a diffusion type of action. This application teaches away from the standard common nozzles where an expander is required to cause diffusion (diffusion may be defined as the converting of a narrow dense stream of a fluid into a broader, gentler application). Also, expander nozzles are often heavy since they are built to increase the flow area, and consequently use more material than the original discharge tube or nozzle. This application presents a lightweight heat retentive diffuser nozzle that has a converging designed envelope rather than a diverging envelope design.
Contemplated fluid projection devices may include, but are not limited to, steam generators, heat guns, pressure washers, grit blasters, and paint sprayers. The nozzle of any of these devices may be equipped with a guard comprised with at least one spacing arm, possibly comprised of a coil spring, configured to a specified length, depending on the application, which will allow the exhaust end of the fluid projection device to get no closer than the length of the spacing arm of the guard. The length will be such that the fluid is applied in the “sweet spot” which optimizes coverage. The nozzle guard equipped with spring spacing arms, while allowing an approach of a set distance from a surface, will allow some lateral movement parallel to the working surface as the spring flexes and bends, but not enough to appreciably reduce the distance between the nozzle and the surface resulting in surface damage.
The mechanical attachment of the nozzle guard to, or near, the exhaust nozzle may be permanent or temporary. Temporary attachments may be adjustable. The nozzle guard may be welded or affixed with screws, rivets, or other fasteners to the nozzle. The base of the nozzle may be threaded allowing for a guard provided with a like threaded ring affixed to the spring to be screwed onto the nozzle. Clamping and friction fitting of the nozzle guard equipped with a non-threaded ring are also contemplated.
The length of the nozzle guard will depend on the fluid that that is projected, and the velocity and strength of the projection and coverage required. The nozzle guard will be configured of a material capable of resisting the fluid to be projected (heat, cold, wear, abrasion, etc.). In most cases, one spacing arm will be sufficient, but in others, more than one arm is contemplated, possibly positioned around the exhaust nozzle of the projection device.
A preferred embodiment of the presented diffusive nozzle guard is for use with superheated steam generators; however, the use of the described guard and diffuser is contemplated with any fluid producing or projection device requiring a diffused spray or a greater area of fluid coverage. In this embodiment the guard would be heat retentive as well. A nozzle guard is contemplated with spacing arms, possibly comprised of springs positioned in line with a steam exhaust nozzle at a length determined to prevent damage to surfaces by the steam. Other embodiments may have more than one nozzle guard or spacing arms.
The nozzle guard is affixed to the steam generator next to the steam exhaust nozzle generally parallel to the nozzle and parallel to the direction of the generated steam. The spacing arm, or arms, may be equipped with a hard, plastic cap at the end intended to contact a surface. The purpose of the guard is to prevent a user from placing the device too close to soft matter such as PPE (cloth) or paper. The steam and steam gas velocity may experience flow velocities from a low 0.1 m/s to 10 m/s at the hot exit at about 100-1000° C. The guard is further comprised of a diffuser affixed to the nozzle at the point at, or near, where the nozzle guard is attached to the nozzle. The diffuser may be comprised of a metallic wire mesh. The mesh may be configured in various shapes and acts to spread out a thin fluid stream into a broader diameter of application. Also, by making the metallic mesh out of metal the heat can be manipulated and retained.
In this embodiment, the nozzle and nozzle guard need to be made of a material that withstands 500° C., allows lateral flexibility, does not corrode in steam or air, adheres to materials, and can be welded to an attachment that screws on to the application nozzle. The nozzle guard may be constructed of material of about 1/16″ in diameter and is 3″-6″ in length. It is comprised of a lightweight material that does not absorb the emitted heat of the steam but transmits the heat effectively. The nozzle guard may be configured allowing for fixturing of temperature indicators and biomarkers to enable a method of ensuring that that the steam impact region is at a point where a microbe load reduction efficacy is assured and optimized.
The nozzle guard may be configured at lengths to accommodate the heat resistances of various materials. The nozzle guard configuration will allow some lateral (sideways) movement along the surface perpendicular to the steam flow. Stiffness in the nozzle guard needs to be maintained to prevent it from bending and allowing the steam to get too close to the surface.
As stated above, the nozzle may be equipped with a means of diffusion that may be comprised of fine wire mesh having hole diameters from 0.01 mm to 3 mm and a corresponding web of the mesh of fine wire with an average diameter between 0.001 and 1 mm. Stainless steel and other heat resistant wire meshes are contemplated. The minimum distance between the exhaust port and a surface allowed by the guard will be such that the fluid is applied in a “sweet spot” where the fluid is most effectively applied to an optimized surface. When used with a superheated steam generator the wires of the diffuser mesh retain the heat as well as the steam in a gaseous state because the wire mesh is heated by the steam. The holes of the mesh diffuser also act to prevent ejection of any water. The mesh diffuser may be configured in any desired shape that retains the heat of the diffused fluid while dispersing it over a wide area including, but not limited to, convergent, conical, round or balloon shapes. The mesh diffuser will act to disperse a fluid flow (superheated steam) over a broader area than an undiffused stream. It has been found that mesh configurations that are convergent (taper down to a smaller diameter away from the nozzle) rather than divergent (become larger in diameter away from the nozzle and exhaust end of device) spread out the flow of superheated steam over a larger area in a more effective manner than the standard divergent design that is taught by the prior art. In practice, the fluid stream comes into contact with the mesh and is directed in the direction of the mesh, possibly perpendicular to, or at an angle away from, the mesh opening thereby dispersing the flow. Such diffusers may be affixed to the nozzle guard in a position close to the exhaust end or nozzle of the fluid projection device. Such convergent diffusers may also be used with nozzle not comprising guards.
A further embodiment of the contemplated fluid diffuser is presented in
An embodiment of an exhaust tube 90, or constricted space, with an affixed nozzle 60 that may be part of a superheated steam generator 50 or other fluid application device is depicted in cross section along the fluid flow as indicated by the arrow in
Although preferred embodiments of the fluid diffuser and method are presented in the above specification, the scope of the invention is not to be limited by them. Other diffuser configurations and fluid applications and equivalents are anticipated by the applicants.
This application claims the benefit of U.S. provisional application 63/345,075 entitled “Heat Retentive Diffusive Light Weight Anti-microbial Steam Nozzle Enabled With a Convergent Envelope” filed on May 24, 2022, by the inventors, the disclosure of which is incorporated by reference herein in its entirety. This application also contains references to U.S. patent application Ser. No. 17/462,052, published as US2022/0072577 A1, entitled “Fluid Nozzle Guard” filed by the inventors on Sep. 31, 2021, which is disclosed herein by reference in its entirety.
Number | Date | Country | |
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63345075 | May 2022 | US |