AIR-BLADE, SILENCER AND SEPARATOR APPARATUS AND METHOD
20170354753 · 2017-12-14
Inventors
Cpc classification
B05B1/002
PERFORMING OPERATIONS; TRANSPORTING
B05B14/00
PERFORMING OPERATIONS; TRANSPORTING
Y02P70/10
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B05B7/2424
PERFORMING OPERATIONS; TRANSPORTING
B05B7/0012
PERFORMING OPERATIONS; TRANSPORTING
A61L9/14
HUMAN NECESSITIES
International classification
A61L9/14
HUMAN NECESSITIES
B05B7/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Silencing and separation in a cold-air, essential-oil, diffuser apparatus and method pass flow through a channel having comparatively high aspect ratios of length to thickness and width to thickness. Curved, tapered, non-parallel, and quasi random surfaces reduce probability and power of resonant frequencies. Offsetting flow through a channel is followed by impingement against an obstructing surface, redirection elsewhere within a drift (separation) chamber, and exiting through a smaller, and differently oriented exit port. Silencing is improved by changes of cross-sectional area creating high-pass and low pass acoustic filters, changes of direction, and absorption of acoustic energy in fluid-droplet-laden air.
Claims
1. A method of atomizing liquid in a flow of air, the method comprising: providing a source of the liquid and a source of the air, the air pressurized to urge a flow characterized by thickness, width, and length; providing an atomizer dispersing into the flow a portion of the liquid as droplets entrained therein; providing a first drift chamber receiving the flow and changing a direction thereof prior to exiting therefrom; providing a channel conducting the flow, having first and second ends, and defining an aspect ratio of length to thickness thereof greater than one, and an aspect ratio of length to width thereof greater than one; and providing a second drift chamber connected to the second end, opposite the first drift chamber at the first end, imposing at least one change of direction of the flow prior to exit therefrom.
2. The method of claim 1, wherein the first drift chamber is shaped to impose more than one change of direction of the flow.
3. The method of claim 2, wherein the second drift chamber imposees more than one change of direction of the flow.
4. The method of claim 3, wherein each of the first drift chamber and the second drift chamber impose upon the flow at least three changes of direction, an acceleration, and a deceleration.
5. The method of claim 1, further comprising providing a channel comprising an air blade wall enclosing the entire flow of air, and droplets contained therewithin, passing as a blade of air, having a thickness is less than a width thereof and less than a length of the flow therethrough, between the first drift chamber and the second drift chamber.
6. The method of claim 5, further comprising providing an outlet configured as an exit port from the second drift chamber, the outlet offset from the air blade to cause the flow to change direction at least three times in order to pass from the air blade through the exit port.
7. The method of claim 6, further comprising providing an eductor as the atomizer.
8. The method of claim 4, further comprising integrating the second drift chamber with a separator plate dividing the first drift chamber from the second drift chamber, the channel passing through the separator plate.
9. The method of claim 1, wherein the first drift chamber is separated from the second drift chamber by a channel extending therebetween and characterized by walls defining a channel length and channel thickness, substantially less than said channel length and calculated to establish a laminar flow profile effective to separate out comparatively larger droplets against the walls, while leaving entrained in the flow comparatively smaller droplets sufficiently small that aerodynamic drag of air thereagainst is sufficient to overcome settling by gravity or impingement of the comparatively smaller droplets against solid surfaces.
10. A method of separating out comparatively larger liquid droplets from comparatively smaller liquid droplets in a flow of air, the method comprising: providing an atomizer atomizing a liquid in a flow of air; passing the flow of air into a first drift chamber requiring at least one change of direction between the atomizing and an exit therefrom; passing the airflow through a channel having an aspect ratio of a minimum width to a length of travel of from about one third to about one twentieth; passing the airflow through a second drift chamber requiring at least one change of direction between introduction of the flow into the second drift chamber, and exit thereof from the second drift chamber; and discharging the flow containing only the comparatively smaller droplets of liquid entrained therein into an atmosphere surrounding the second drift chamber.
11. An apparatus comprising: a bowl; a neck connecting the bowl to a flow of air containing droplets of a liquid, comprising comparatively larger droplets and comparatively smaller droplets; an air blade constituting a channel having an aspect ratio of minimum thickness to length of travel ranging from about 0.3 to about 0.05 protruding into the bowl; a first drift chamber passing the flow through at least one change of direction prior to exiting therefrom into the channel; and an exit port discharging the flow from the bowl at a location offset away from the air blade radially to impose two changes of direction in the flow between the channel and the exit port.
12. The apparatus of claim 11, further comprising a cap separable from the bowl, the cap and bowl together forming a second drift chamber: a separator plate separating an interior volume of the second drift chamber from a source of the flow of air to allow substantial flow therebetween only through the channel.
13. The apparatus of claim 11, wherein the channel terminates at a lower end with a drip edge urging a portion of the liquid coalesced from the comparatively larger droplets to move to a lowest point on the drip edge.
14. The apparatus of claim 13, wherein the channel is curved in a circumferential direction with respect to a vertical axis through the bowl.
15. The apparatus of claim 14, wherein the bowl has a plate at an axially lower end, perforated to pass the portion of the liquid coalesced to exit to a reservoir therebelow.
16. The apparatus of claim 15, wherein the cap includes an exit port discharging the flow in an axial direction substantially parallel to the flow through the channel.
17. The apparatus of claim 11, wherein the flow coalesces a portion of the comparatively larger droplets by subjecting them to lateral drift toward a wall of the channel due to laminar flow in the channel.
18. The apparatus of claim 11, further comprising an atomizer providing the flow.
19. The apparatus of claim 18, further comprising a separator plate separating the atomizer from an interior volume of the bowl except through the channel.
20. The apparatus of claim 18, wherein the atomizer comprises a drift region collecting a portion of the comparatively larger droplets and returning them to a reservoir therebelow.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] The foregoing features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0064] It will be readily understood that the components of the present invention, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of various embodiments of the invention. The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.
[0065] Referring to
[0066] By silencing is meant the reduction in sound propagated outside a diffuser 12 or system 12 in operation. By separating is meant the separation from a flow of air, certain, entrained droplets in the flow of air. Typically, as used herein, the expression separator or separating refers to removing “comparatively larger” droplets. Comparatively larger droplets refer to those droplets that are sufficiently large that their mass, and therefore their weight under the influence of gravity, are sufficiently large compared to their aerodynamic drag in a flow of modest to velocity, typically the circulation of room air, that such droplets will fall out of the flow of air within the room, typically 15 to 20 feet.
[0067] However, comparatively smaller droplets remain in the airflow constitute the objective. Thus, comparatively smaller droplets are those that are sufficiently small that they will drift in a flow of air at modest velocities, typically associated with ventilation motion of the air in a ventilated room, indefinitely. Indefinitely means at least an hour or more, and will typically be several hours, or until the room air has been effectively exchanged.
[0068] In a system 12 equipped with a silencer-separator 10, the system 12 is effectively constituted as a cold-air, diffusion apparatus 12, also referred to simply as a diffuser 12. A diffuser 12 may draw from a reservoir 14 containing a suitable liquid. Liquids typically may include essential oils, mixtures of solvents with the essential oils, emulsions of water, other liquids, or the like. Typically, the content or liquid in a reservoir 14 is drawn through a tube 15 or line 15 penetrating to a location near the bottom of the reservoir 14. An atomizer 16 draws liquid content from the reservoir 14 through the line 15 to be atomized. By atomization is meant the breaking up of a liquid, flow of liquid, or the like into a random distribution, which will typically be a Gaussian distribution, also known as a normal distribution.
[0069] Atomization may be done by a venturi or an eductor. A venturi is a conduit narrowing to a throat through which a flow of fluid passes, the conduit progressing from a comparatively larger diameter to a smaller diameter and ultimately to a narrowest diameter, followed by an increase in diameter. By the word diameter is meant hydraulic diameter. A hydraulic diameter is four times the area divided by the wetted perimeter. In a circular cross-sectional area, hydraulic diameter equals circular diameter. In a square cross section, hydraulic diameter equals the length of one side.
[0070] In any other shape of a cross section, the hydraulic diameter provides a value that may be used for effective diameter in hydrodynamic or aerodynamic equations of flow. Hydraulic diameter relates the cross-sectional area to the shape of the perimeter or circumference of or about a flow. Thus, in speaking of diameter, the expression means effective diameter or hydraulic diameter. That is, any time the word diameter is used, what is meant is the effective diameter.
[0071] A venturi relies upon dynamic pressure head. Typically, in a flow through a venturi, dynamic pressure head is substantially constant. There is some amount of drag, but it is substantially negligible in many instances. Thus, assuming a constant, dynamic pressure head means that the static pressure contribution and the velocity contribution to dynamic pressure head add to the same constant value throughout. Thus, whenever the cross-sectional area narrows, the velocity must increase. Thus, the velocity head component must increase, causing a reduction in the static pressure head contribution.
[0072] The result of the reduction in static pressure head at the narrowest portion or the throat of a venturi results in a low pressure region that tends to draw against the walls. Thus, a penetration, tube, pipe, or a port in a wall, or the presence of a tube, inlet, or other access by a second fluid at the exact throat (narrowest portion) of a venturi will result in drawing that fluid into the flow.
[0073] An eductor is an entirely different mechanism. An eductor is a device found in virtually all gas stoves, gas furnaces (e.g., propane, natural gas, butane, etc.) and has been for decades, in fact, over a century. Likewise, eductors are used in various pumping systems, particularly for pumping fluids that will damage pumps. Sewage is one example.
[0074] For example, pumping a flow of sewage sludge is not appropriate for a mechanical pump. Damage by wear and corrosion would be swift and certain. Instead, a cleaner fluid may be injected as a high speed jet relative to a comparatively low speed flow of sludge. The high speed jet imparts momentum from itself (e.g., small mass, high velocity) to the flow of sludge (e.g., large mass, comparatively low velocity).
[0075] An eductor thus relies on direct momentum transfer between a first flow at a comparatively higher velocity into a second flow at a comparatively lower velocity. Momentum transferred from the higher speed jet into the lower speed surrounding fluid results in motion of the comparatively slower mass of fluid, resulting in drawing in more of that surrounding fluid into the jet as it progresses forward.
[0076] Eductors 18 have been described in considerable detail, along with their operation, in the references incorporated hereinabove by reference. Typically, an eductor 18 may be made up of a variety of components, resulting in a flow of air therethrough shattering or comminuting liquid, received through the tube 15, in an eductor jet 28, not shown in entire detail here, but included in great detail in the references incorporated herein by reference.
[0077] The atomizer 16 may include a housing 17, as a part of which the eductor 18 may fit its own seals 22 air jet nozzles 24 including a jet aperture 25 all fitted into a housing 26 for containment. The eductor nozzle 28 receives air from the jet opening 25 through the eductor nozzle 28, thus drawing with it liquid captured therebetween, that is, between the air nozzle 24 and the eductor nozzle 28. Thus, out of an opening in the eductor nozzle 28 sprays an airflow containing a distribution of droplets of the liquid content drawn from the reservoir 14.
[0078] The droplets from the eductor 18 enter a separation chamber 20a or drift chamber 20a. The drift chamber 20a may also be referred to as a separator 20a. A separator 20, generally, operates by several mechanisms. First of all, the specific separation chamber 20a as constituted by the housing 17, presents a wall against which the flow will impinge. Comparatively larger droplets will tend to strike the wall. Comparatively smaller droplets will tend to remain in the flow of air.
[0079] That is, comparatively larger droplets having more mass, and therefore more weight, associated with greater momentum within themselves, are sufficiently heavy that they cannot change direction due to the insufficient aerodynamic drag of air flowing thereby. Accordingly, comparatively larger droplets strike a wall, coalesce there or shatter. To the extent that the droplets coalesce, they will drift downward toward the reservoir 14. To the extent that the droplets shatter, comparatively larger portions may again be subjected to coalescing against the wall. Sufficiently small droplets will be entrained (carried by aerodynamic drag) within the airflow, eventually finding their way out of an exit from the drift chamber 20a. A separator plate 30 may divide the separator chamber 20a of the atomizer 16 from a second separation chamber 20b or drift chamber 20b of the silencer-separator 10. Trailing letters or reference numerals indicate a specific instance of the item type identified by the numeral.
[0080] The silencer-separator 10 may begin at its lower extremity with a neck 32. The neck 32 may include a collar portion 34 or collar 34 that has a smaller or larger diameter than does the neck 32. In the illustrated embodiment, the collar 34 has a smaller diameter, in order to fit into the housing 17 of the atomizer 16. In other embodiments, the collar 34 may have a larger diameter than the neck 32, thus forming a detent 34 to constrain the neck 32 within the housing 17 of the atomizer 16. In other embodiments, threads may substitute for any other retainers.
[0081] However, in the illustrated embodiment, one purpose for the collar 34 is to provide a close fit against the surface 36 in the housing 17. Likewise, a registration 38 or notch 38 in the neck 32 fits against a matching or mating protrusion on the surface 36. Thus, by not being threaded, the neck 32 may slide into the housing 17, with the collar 34 snuggly fitting against the surface 36, and being rotatable for registering the registration 38 or notch 38 therein.
[0082] Registration 38 assures that the channel 40 or air blade 40 itself is opposite the eductor nozzle 28 of the atomizer 16. This, as it turns out, is important for reducing sound. Sound waves propagate up through the channel 40 or air blade 40. The channel (cavity) 40 may be called an air blade 40 and creates a blade of air or an air blade, because it has a comparatively narrow thickness relative to both its overall width, and its overall length in the direction of flow (e.g., vertically).
[0083] The air blade 40 or channel 40, by being positioned obliquely, in fact a right angle, in the illustrated embodiment, with respect to the flow of the eduction spray, provides much damping, and uncoupling of the soundwaves by virtue of the difference in characteristic lengths between it and the surrounding drift chamber 20b. Various characteristic lengths (e.g., diameter, varied diameter along its height, depth, varied depth in view of the capered bottom surface, and so forth) exist throughout.
[0084] Referring to
[0085] Referring to
[0086] Referring to
[0087] One benefit of a sliding fit, snap fit, or the like is that the registration 48 may be matched with a corresponding registration 49 on the cap 46. Thus, the bowl 44 and cap 46 may be visibly rotated with respect with one another in order to match up the registration 48 at the appropriate location. The effect of the registration 48 is to establish the position of the air blade 40 with respect to the outlet 50. Typically, the registration 48 and its matching pin 49 may be reversed or may be changed in any suitable manner, so long as registration therebetween is promoted.
[0088] Effectively, the outlet 50 serves best if offset by at least 90 degrees from the plane or center plane that would effectively form a reflectively symmetric surface passing vertically through the tower 43, air blade 40, and its walls 42. As a practical matter, it is proper to speak of the air blade 40 as the channel 40, or as the flow of air 51 therethrough. Thus, the flow 51 through the channel 40 represents an air blade 40, 51. Similarly, one may speak of the air blade as the structure 42 or walls 42 that form the channel 40 that passes the flow 51. Thus, herein, the term air blade 10, 40, 43, 51 should be clear from its context.
[0089] It has been found that the outlet 50 serves best if offset by 180 degrees from the channel 40, or the center line or center plane through the channel 40. One may think of a center plane through the channel 40 as a vertical plane extending upward and horizontally bisecting both the inner wall 42a and outer wall 42b around the channel 40. The separator plane or dividing plane would thus form a vertical plane of symmetry for the air blade 40, the flow 51, the walls 42, the bowl 44, the cap 46, and so forth.
[0090] Referring to
[0091] The bowl 44 and cap 46 may be fitted together with a notch registration 38 and a corresponding pin 49 or peg 49. Meanwhile, proceeding circumferentially around virtually the entire circumference of the cap 46 may be a capillary break 52. A capillary break 52 constitutes a gap 52 sufficiently large that capillary action of the contained fluid droplets coming from the eductor and coalescing in the bowl 44 will not cross. Accordingly, oil will not collect or seep out of the gap or the sealing surfaces between the bowl 44 and the cap 46.
[0092] For example, the vertical surface 53 may be comparatively tight, and therefore may attract, due to surface tension, collection of a certain quantity of oil or other contents being coalesced from droplets. However, the capillary break 52 interferes with transport to anywhere outside the bowl 44.
[0093] Regarding asymmetric features of the silencer-separator 10, one will immediately note that in
[0094] Any basic, engineering, fluid-mechanics book will describe conditions and show the flow profile for a laminar flow and for a turbulent flow in a narrow passage. In either event, a boundary layer near the surfaces of the walls 42a, 42b will form, moving very slowly and collecting liquid droplets that touch the walls 42a, 42b.
[0095] Droplets thereby adhere to the walls 42 and other liquids coalesce thereagainst. A direct result is a flow down the inside surfaces of the channel 40. That flow along the outer wall 42b will eventually find its way down into the housing 17 and neck 32 of the atomizer 16, and thereby to the reservoir 14. Meanwhile, any coalesced droplets that impinge against the inner surface of the bowl 44 will drain downward toward the drain 58.
[0096] One will note that the drip edge 44, by being angled downward from one extreme to the other, creates a drip point 56 at the lowest location 56 of the drip edge 54. Droplets coalescing against the inner wall 42a, within the channel 40 will flow down to the drip edge 54, and thence to the drip point 56, where they will form droplets that will readily drop back into the housing 17 from the neck 32. Droplets tend not to stop along the drip edge 54, but collect and move downward toward the drip point 56. Thus, droplets collected from the channel 40 will typically adhere to the wall 42, move toward the outer wall 42b, and thereby drip back through the neck 32 and into the housing 17 and reservoir 14.
[0097] The drain 58 may be provided with a breaker 60 or surface tension breaker 60 constituted by a sharp edge or multiple sharp edges on a protrusion 60 away from the neck 32. This protrusion 60 may have sharp edges in order to promote the formation of droplets therearound, stripping them from the drain 58, so they do not collect, become blocked, or otherwise form larger droplets suspending from the drain 58. The breaker 60 operates as a surface tension breaker 60 providing a solid surface promoting flow away from the drain 58.
[0098] In general, the capillary break 52, the surface tension breaker 60, the drip edge 54 and drip point 56, and so forth are innovations deemed appropriate in order to encourage complete draining of liquids from the silencer-separator 10. Typically, the system 12 may be taken apart, the reservoirs 14 may be changed out with different contents, and so forth. By encouraging prompt and complete draining of all liquids back to the reservoir 14, the silencer-separator 10 is maintained cleaner, will be less likely to drip or otherwise transfer oily contents to the hands or clothing of a user, or to a surface on which any component may be temporarily set when dismantled.
[0099] Referring to
[0100] Thereafter, the flow 51 will be diverted to flow in other directions throughout the drift chamber 20b. To the extent that airflow progresses radially, it may impinge against the inner surface 66 of the bowl 44. Ultimately, a flow 70 may exit the outlet 50. However, at least three changes of direction must occur in most of the flow 51 in order for the flow 51 or droplets and air within the flow 51 to exit the channel 50, since the air blade 51 comes to a halt due to striking the inside surface 64 of the cap 46, progress horizontally, radially, and the like in order to reach the outlet 50. The flow must then turn to progress vertically out through the port 50.
[0101] Moreover, the change of shape between the comparatively thin but wide air blade 51 from the channel 40 and the comparatively narrow, typically circular or otherwise cylindrical shape of the outlet 50, requires expansion of the flow into a larger area, out of a comparatively smaller cross-sectional area. It then reduces from that comparatively larger cross-sectional area back into an even smaller cross-sectional area of the exit 50.
[0102] This repeated change of cross-sectional area available to accommodate the flow also results in drifting, slowing, and jinking (zig-zagging, sharp turns back and forth, darting), which action therefore provide more dwell time, repeated acceleration and deceleration of flow, and so forth to promote more drifting and smashing by comparatively larger droplets against solid surfaces.
[0103] Only droplets small enough that their mass, momentum, and fluid dynamic drag permit them to remain with the air flow through all its twists, turns, stops, starts, accelerations, and decelerations will remain in that flow when it exits the systems 10, 12.
[0104] This is the ultimate definition of “small” droplets, those that exit the separator 12 with the air flow. At any space, conduit, path, location, or the like, the “comparatively larger droplets” are those that strike a solid surface and coalesce. “Comparatively smaller droplets” remain entrained in, and exit that space with, the flow of air therethrough.
[0105] The silencer-separator 10 illustrated has proven highly effective in eliminating the sound of hissing generated by an atomizer 16, and particularly the eductor 18. It is also very effective at eliminating comparatively larger droplets in the airflow 70 proceeding from the outlet 50. Those comparatively larger droplets are those that would otherwise drift downward at an unacceptable rate to land on furniture, counters, and flooring. The objective is for all droplets released to evaporate or drift with room air indefinitely or sweep out with ventilation air exiting the treated space.
[0106] The sound is minimized, typically reduced by from about six to about ten decibels in volume (intensity, amplitude), and typically provides on the order of about eight decibels of reduction of sound when the outlet 50 is 180 degrees out of phase with respect to the tower 43 of the air blade 51. Meanwhile, the elimination of comparatively larger droplets or “spitting” droplets that are sufficiently large to settle out on furniture or other surfaces nearby is eliminated so long as the cap 46 has been rotated to place the outlet 50 at about 90 degrees or greater out of phase with the center plane of the air blade 40.
[0107] Other features of a silencer-separator 10 in accordance with the invention are the various changes in cross-sectional area, shape, and so forth. By providing suitable taper to the shape of the bowl 44, the variation in diameter tends to avoid establishing a single resonant length that may promote resonant frequencies of audible sound waves during operation of the system 12. Likewise, by canting or tilting the separator plate 30 that operates as a floor 30 of the bowl 44, a single resonant length or height is less likely. Similarly, below the floor 30 (i.e., separator plate 30), vertical height is affected by the angled separator plate 30.
[0108] The shape of the tower 43 and air blade 51 is capable of accomplishing several functions. First, maintaining a distance from the exit 50 or outlet port 50 is accommodated by wrapping the walls 42 along the path substantially parallel to the surface 66 inside the bowl 44. Also, this provides for maintaining distance away from the outlet 50. Although a straight (non curved) channel 40 may operate to provide the separation function of the channel 40, coalescing droplets along the walls 42a, 42b, the sound is prevented from obtaining consistent characteristic lengths by the curvature, and its resulting distribution of the flow 51 throughout the drift chamber 20b. In other words, care has been taken to reduce the incidence of single, characteristic lengths that might promote or support resonant frequencies that may increase propagation of sounds.
[0109] Referring to
[0110] One will also note the manufacturing elegance of the outer wall 42b being essentially coincident with the neck 32 generally. Meanwhile, the formation of the channel 40 by the inner wall 42a, may be molded from the two sides or surfaces of the separator plate 30 that forms the floor 30 of the bowl 44, and the sealing of the first drift chamber 28 in the housing 17. An additional separator plate, or even a micro-cyclone may still be placed below the system 12.
[0111] The present invention may be embodied in other specific forms without departing from its purposes, functions, structures, or operational characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.