Filter drift elimination from spray nozzle

Abstract

The present invention is a multiplexed inertial coalescence filter system that minimizes spray drift and maximizes droplet transfer efficiency to improve the precision and safety of industrial spray applications. In an alternate embodiment, a hollow multiplexed inertial coalescence filter is rotated around its longitudinal axis to capture droplets or particles from a fluid stream flowing therethrough.

Description

[0001] FILTER DRIFT ELIMINATION FROM SPRAY NOZZLE

[0002] RELATED APPLICATION

[0003] This application is entitled to priority from U.S. Provisional Patent Application 63 / 706,209 filed October 11, 2024 by the inventors herein, which is hereby incorporated by reference as if set forth in full herein.

[0004] TECHNICAL FIELD

[0005] The present disclosure generally relates to multiplexed inertial coalescence filters and their uses in spray systems.

[0006] BACKGROUND

[0007] Spray systems in multiple modalities are leaky and wasteful. When the spray material is valuable, capturing the unused material is essential and challenging. Spray turns into mist due to the physics involved, making capturing an extreme challenge. Closing the spaying system in a box is only sometimes possible and does not solve the capturing problem. The leakiness, on the other hand, may result in environmental contamination that is very hard to eliminate.

[0008] Spray nozzles that produce droplet sprays are used in many industries. No spray method has 100% droplet transfer, and all spray methods produce considerable amounts of drift, including droplets sprayed outside of the spray cone. Mitigating the loss of droplets into the environment is an essential job performed by various systems. The sprayed liquid may be costly, toxic, or hazardous and may have negative consequences for other systems and processes if allowed to spread to the environment. Developing technologies that minimize spray drift and maximize droplet transfer efficiency remains a priority across industries, with ongoing research and innovation aimed at improving the precision and safety of spray applications.

[0009] This disclosure expands upon prior multiplexed inertial coalescence filter technologies, and develops the use of these filters in spray systems targeting various applications. These applications include, but are not limited to: (1) cleaning and washing processes using sprays of water and other solutions; (2) cooling solids via spray cooling with water or other coolants; (3) gas cooling & conditioning wherein droplets may condense from air streams; (4) coating applications using liquid droplets; (5) dust control; (6) fire protection applications where sprays of fire retardants and fire extinguishing materials are of interest; (7) humidification where water droplet sprays humidify air, but may require capture of these droplets; (8) lubrication tank cleaning using droplet sprays; (9) spray drying; (10) NOx control using droplet sprays; (11) sulfur burning; (12) vacuum distillation processes that may require droplet capture; (13) marine fire suppression using nozzles that produce droplets of water or other fire retardant materials; (14) deluge spray; (15) gas scrubbing applications using chemically active droplets; (16) odor control using chemically active droplets; (17) precision lubrication using droplet sprays; (18) foam control using spray foams; (19) air inlet cooling; (20) aeration / air stripping; (21) cleaning / washing processes in general; (22) coating processes in general, which use droplet sprays; (23) metal descaling;

[0010] (24) disinfecting processes using droplet sprays of hot liquids or chemically active liquids;

[0011] (25) general mist elimination; (26) snowmaking processes; (27) pasteurization; (28) pickling; (29) roll cooling; (30) particle-liquid separations; (31) particle, liquid, and gas separations.

[0012] BRIEF DESCRIPTION OF THE INVENTION

[0013] Multiplexed inertial coalescence filters may be used in various configurations to capture droplets from air streams that arise from sprays produced using nozzles. One configuration is shown in Fig. 1., where a spray nozzle is shielded with a cone-shaped multiplexed inertial coalescence filter. Air may be pulled through the filter, or the filter may function passively without active airflow. A pump may pull liquid from the filter medium into a solution tank and then back to the spray nozzle. Pumping can occur from various regions, depending on the filter design. The filter may also be used with no pump and may use gravity to drain the filter medium passively. This type of configuration may be used with various spray nozzles to capture unintended drift or overspray from the nozzle.

[0014] BRIEF DESCRIPTION OF THE FIGURES

[0015] The present disclosure may be better understood, and its numerous features and advantages are made apparent to those skilled in the art by referencing the accompanying drawings. Using the same reference symbols or descriptive terms in different drawings indicates similar or identical items.

[0016] Figure 1. A multiplexed inertial coalescence filter assembled in a cone-shaped jacket around a spray origin or nozzle.

[0017] Figure 2. A hollow cone jacket around a spray nozzle with air pulled through the cone into a multiplexed inertial coalescence filter. The filters capture droplets from the air, where it is drained into a solution tank for reuse.

[0018] Figure 3. A multiplexed inertial coalescence filter with helical flow passages capturing a stream of incoming droplets.

[0019] Figure 4. Multiplexed inertial coalescence filters may be manufactured in a V-shape, where the filter is made of two planar sections that combine to form the V-shape.

[0020] Figure 5. Multiplexed inertial coalescence filters may be manufactured in a series of V- shapes to maximize filter area.

[0021] Figure 6. Multiplexed inertial coalescence filters may be manufactured in a hollow cylinder.

[0022] (a) A sketch of the filter cross-section, (b) A CAD model of a cylindrical filter unit and (c) CAD model showing the cross-section of the filter unit.

[0023] Figure 7. Multiplexed inertial coalescence filters may be manufactured in a hollow cone.

[0024] Figure 8. (a) CAD model of a circular multiplexed inertial coalescence filter with drain network shown, (b) Filter cross section with drain network shown.

[0025] Figure 9. CAD model of a multiplexed inertial coalescence filter with rotation direction and Figure 10. A tubular multiplexed inertial coalescence filter mounted on an axis. The filter is rotated using a driving force (i.e., motor) and a shaft to generate airflow and centrifugal forces to separate droplets from air.

[0026] Figure 11. An “umbrella” shaped filter with filtration features embedded for droplet and particle capture.

[0027] Figure 12. An “umbrella” shaped filter, similar to that shown in Fig. 11, with filtration features embedded for droplet and particle capture and with tailored porosity for preferential liquid wicking and draining. The filter envelops a spray nozzle.

[0028] Figure 13. A multiplexed inertial coalescence filter with a motor and rotating eccentric mass generating vibrations on a filter.

[0029] DETAILED DESCRIPTION OF THE INVENTION

[0030] As shown in Fig. 2, a hollow cone shields a spray nozzle. The hollow cone has air pulled through a channel using a fan, blower, or some other source of airflow or pressure differential. Droplets are carried through the channel with the airflow and into a multiplexed inertial coalescence filter assembly. The multiplexed inertial filter may be made in any suitable configuration. The filter may be actively or passively drained to a solution tank or may not be drained at all (i.e., catch and hold solution). When the solution is drained, the liquid may be stored or returned to the spray nozzle for reuse.

[0031] The multiplexed inertial coalescence filters may be manufactured in a variety of geometries, including as a planar filter, as a conical filter, as a cylindrical filter, and in a “V-shape” (as shown in Figs. 4 & 5). These filters may also be manufactured in the shape of a tube, as shown in Fig. 10. The tubular filter in Fig. 10 is mounted on a shaft, which may be rotated via a motor or other suitable means. The rotation of the filter induces circular motion of air in the core of the filter, which results in centrifugal forces on streams of droplets in the core of the filter. These centrifugal forces imparted on droplets cause the droplets to traverse from the core region of the cylinder to the outer region (toward the filter). Once the droplets impact the filter, they are captured from the air stream in the filter medium. The filter will eventually saturate with liquid. In this case, the filter medium may be drained passively via gravity, as shown in Fig. 10, or maybe actively drained using a pump or other mechanism. This mechanism may be used for droplets or particles, may be used in solid or porous filters, and may be used with filters that are conical in shape.

[0032] Planar multiplexed inertial coalescence filters, shown in Fig. 3, may be manufactured. Other methods to manufacture a filter include combining two planar sections to make a V-shaped filter, shown in Fig. 4. The V-shaped filter may be made of two planar filters, created as a single unit, or made of multiple parts. The V-shaped filter may be arranged so that the flow goes through two directions, as shown in Fig. 6a and Fig. 6b. One advantage of a V-shaped filter is increased surface area and, therefore, reduced pressure drop across a filter for a given flow rate. These V-shaped filters may also be serialized such that they comprise numerous V-shapes to make a large filter that maximizes filter area, as shown in Fig. 5.

[0033] Multiplexed inertial coalescence filters may also be manufactured in a hollow cylinder configuration where the filtration features traverse from one end of the hollow cylinder to the other, as shown in Fig. 6. These cylindrical filters increase filter area, reducing pressure drop across the filters. Cylindrical filters may also be utilized in a variety of system geometries.

[0034] Multiplexed inertial coalescence filters may also be manufactured in a hollow cone where the filtration features traverse from one end of the hollow cone to the other, as shown in Fig. 7. These cone filters increase filter area, reducing pressure drop across the filters. Cone-shaped filters may also be utilized in a variety of system geometries.

[0035] Filtration features in the multiplexed inertial coalescence filters also filter droplets and particles from air streams. These may use helical or other geometries to induce centrifugal forces on droplets and particles. Electrostatic forces may also be used. Once particles and droplets impact the flow passages, they may be absorbed into the filter's media through various means. The media may be a porous material, where capillary forces will result in fluid wicking and migration throughout the media.

[0036] The filters may also be solid and manufactured with various drain networks, as shown in Fig. 8. These drain networks traverse the filter medium and slice through the open passages. When liquid impacts walls, capillary forces or pressure-induced flow from a pump or fan may cause the liquid to flow through the drain network. These drain networks may also be manufactured into a filter where the medium is porous. The drain networks may also be assembled in a filter from a single or multiple monoliths. The drain networks may also be assembled in a filter made from stacked sheets. The drain networks may also be assembled in a planar, V-shaped filter, cylindrical, or conical.

[0037] In a multiplexed inertial coalescence filter, when the medium of the filter is loaded with liquid, we may also rotate the filter to take advantage of centrifugal forces to drain the liquid from the medium, as shown in Fig. 9. The use of centrifugal forces via filter rotation may be used to drain liquid from the filter medium in a planar porous filter, a planar non- porous filter with drain network, a V-shaped filter, a cylindrical filter, or a conical filter, or oval filter.

[0038] The multiplexed inertial coalescence filters may also be manufactured in an “umbrella” shape, as shown in Fig. 11. This “umbrella” shape may be used to envelop a spray nozzle, similar to the configuration showed in Fig. 1 and Fig. 2. This “umbrella” shaped filter may be manufactured using multiple monoliths and may be designed to be collapsable. These filters may also be manufactured with pre-selected porosities. Figure 12 shows another “umbrella” shaped filter made of a series of trapezoidal panels surrounding a spray nozzle. The panels are joined to a catch channel at the bottom which allows liquids to enter a “catch tube” tube-like structure with a porous upper half and solid lower half, allowing liquid to drain from the filter through the top half of the tube and gather in the bottom half of the tube. These tubes are further connected to standard hollow tubes where suction is applied at the drain to draw gathered liquids from the catch tubes. The process is continuous, and where pressure may be applied in a multitude of regions to drain liquid from the filter medium. The filters may also be passively drained by gravity.

[0039] Removal of particles, liquids, or removal of both particles and liquids from the filter medium is of interest for a variety of reasons including: 1) cleaning the filter medium so that it may be reused for continuous filtration operations and 2) capturing and reclaiming liquids and particles of interest for use in downstream operations where these materials may be valued resources or require specific handling for further processing.

[0040] The challenges with removing particles and liquids from the filter medium is that they may be adhered in a variety of ways to the filter surfaces. Particles and liquids that are captured by a multiplexed inertial coalescence filter may adhere to the filters in a variety of ways. The filter material may be solid, porous, or may contain draining features, as shown in Fig. 10. For particles, adhesions forces, including van der Waals forces, may cause particles to adhere to filter surfaces. In addition to van der Waals forces, electrostatic forces may also play a significant role. Charges on particles and filter surfaces may occur spontaneously leading to attraction and adhesion. For wetted filters, capillary forces may cause particles to adhere to filter surface. Capillary forces arise due to the presence of liquid film filter surfaces, which can create a meniscus that pulls particles toward the filter surfaces. In the case of liquids in the filter medium, capillary forces cause the liquid to adhere to the filter material. Some liquids may be very viscous, so it is challenging to drain from the filter medium.

[0041] We can use various methods to remove or liberate particles and liquids from the filter medium. Pressure-driven flows from pumping is possible, as mentioned in this disclosure. Removing from the filter may not be trivial for strongly adhered particles, very viscous liquids, and a combination of liquids and particles. In this case, we may use vibrations to liberate strongly adhered substances from the filters, as shown in Fig. 13.

[0042] Figure 13. shows a multiplexed inertial coalescence filter with a motor and rotating mass. A motor rotates the mass and generates vibrations on the filter due to the rotation of an imbalanced or balanced mass on the motor shaft. In addition to using a mass and motor to generate vibrations, embedded piezoelectric devices may be used to generate vibrations. Other methods to produce vibrations on the filters include the use of ultrasonic transducers, electromagnetic actuators, and, lastly, generation mechanical agitation systems, such as shaking or vibratory conveyors.

[0043] In another embodiment, a multiplexed inertial coalescence filter with a drive means (with or without a rotating mass) may be employed to separate droplets and particulates from a fluid stream that is not associated with a nozzle or sprayer. In such applications, a hollow cylindrical or conic filter is rotated about its longitudinal axis by a suitable drive mechanism and a fluid flow is introduced within the filter. This embodiment is suitable for example, in ducted or conduit flows. The filter may be provided with a means to introduce vibration as previously described, to facilitate draining of captured materials from the filter.

[0044] In describing the above embodiments of the invention, specific terminology and simplification of data was selected for the sake of clarity and brevity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description rather than of limitation and that changes may be made within the purview of the appended claims without departing from the true scope and spirit of the invention in its broader aspects. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.

[0045] The inventors further require that the scope accorded the claims be in accordance with the broadest possible construction available under the law as it exists on the date of filing hereof (and of the application from which this application obtains priority, if any) and that no narrowing of the scope of the appended claims be allowed due to subsequent changes in the law, as such a narrowing would constitute an ex post facto adjudication, and a taking without due process or just compensation.

Claims

WE CLAIM:

1. A system for reducing spray drift of material being sprayed that does not remain in contact with the target of the spray comprising one or more multiplexed inertial coalescence filters arranged to collect sprayed material in droplet or vapor form from a fluid flow.

2. The system of claim 1 wherein the filters are arranged in a cone-shape around the spray origin.

3. The system of claim 2 wherein an airflow is used to direct the spray drift into contact with the filters.

4. The system of claim 1 wherein the filters are drained into a tank for spray material reuse.

5. The system of claim 1 wherein the filters have helical flow passages therein.

6. The system of claim 1 wherein the filters are comprised of planar sections arranged in a V shape adapted to increase the available surface area of the filters.

7. The system of claim 1 wherein the filters are comprised of a plurality of planar sections arranged in a plurality of V shapes adapted to increase the available surface area of the filters.

8. The system of claim 1 wherein the filter is comprised of a hollow cylinder.

9. The system of claim 1 wherein the filter is comprised of a hollow cone.

10. The system of claim 1 wherein the multiplexed inertial coalescence filter further comprises a drain network.

11. The system of claim 1 wherein the multiplexed inertial coalescence filter is rotatable about an axis.

12. The system of claim 11 wherein the rotation of the filter generates airflow and centrifugal forces adapted to separate liquid droplets from the airflow.

13. The system of claim 11 wherein the multiplexed inertial coalescence filter is further provided with a means to induce vibration of the filter.

14. The system of claim 13 wherein the vibration inducing means comprises an eccentric mass mounted on a rotating shaft.

15. The system of claim 1 wherein the multiplexed inertial coalescence filter is configured in an umbrella shape positioned about a spray nozzle.

16. The system of claim 15 wherein the multiplexed inertial coalescence filter is provided with a preselected porosity adapted to promote liquid wicking and draining.

17. A system for filtering materials entrained in a flowing fluid comprising one or more multiplexed inertial coalescence filters configured as a hollow cylinder or cone through which the fluid flows.

18. The system of claim 17 wherein the hollow filter is rotated about its longitudinal axis.

19. The system of claim 18 wherein the hollow filter is vibrated during rotation.

20. The system of claim 17 wherein one or more multiplexed inertial coalescence filters are comprised of planar sections arranged in a V shape.

21. The system of claim 17 wherein one or more multiplexed inertial coalescence filters are comprised of a plurality of planar sections arranged in a plurality of V shapes adapted to increase the available surface area of the filters.

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