Patent Application
20200179966
The present invention has its application within the mechanical and fluidics sectors, especially, in the industrial area engaged in providing spraying nozzles with small droplet size and large flow rates.
Atomizing nozzles capable of spraying one or more liquids into the air in the shape of small droplets are highly sought after in diverse applications such as fire protection (both in indoors systems and outdoors scenarios); decontaminate public areas (e.g. subway stations, railway stations, etc.) and critical infrastructures (e.g. command centres, hospitals, airports, local authorities); industrial manufacturing (e.g. powder metallurgy or extrusion technology); exhaust ad blue or industrial emission cleaning; or snow cannons.
In many of these scenarios, it is of paramount importance to achieve a high flow rate while preserving a small droplet size.
Many different nozzle configurations have already been developed in an effort to fulfil both requirements. In its most basic form, the atomizing nozzle can be implemented with a single cylindrical mixing chamber with an output orifice with a pin in the middle. A liquid inlet and a gas/air inlet are connected to the mixing chamber with a 90° angle between both inlets. Water is feed into the nozzle axially and interacts with the air which enters through the tangential inlet. The mixed fluid flow impacts against the pin, passes through a plurality of slots around said pin and flows out from the orifice.
Nozzle performance can be improved, for example, by including two separate chambers within the nozzle, connected through a plurality of gradient channels. The gas is initially fed to the first chamber (the one further from the output orifice), and is then mixed with the liquid at the second chamber. The axial liquid inlet goes through the first chamber and is directly connected to the second chamber.
Other solutions include air-assist pressure-swirl schemes, where water is supplied from a central inlet and flows through the swirl insert to introduce centrifugal force on water. After spinning in the swirl chamber, water flow out from the small orifice and interact with a strong air flow. Alternatively, water entering from the water inlet may go through a small gap and become a thin liquid sheet. Then it encounters air flow from the outer air inlet, which accelerates the velocity of the water and also increase its instability. High speed air from inner air inlet meets the water at further downstream and blasts it into small droplets.
In spill-return configurations, water is fed from the water inlet and enters the first chamber through three swirl channels. Water in the first chamber can leave the nozzle either from the spill return orifice or from the nozzle orifice. When the full capacity of nozzle is required, valve mounted at spill line will be totally shut so that there will be no liquid being spilled from the nozzle. Once the valve is open, part of the liquid will flow away from the nozzle chamber, resulting in the reduction of flow rate from the orifice. Swirled water flowing out from nozzle orifice will mix with strong air flow in the outer air channel.
Finally, in twin swirl configurations, both the swirl effect of water or air helps with the disintegration of liquid jet and the formation of small drops. Water enters the nozzle accumulates at first chamber and flows to the mixing chamber (second chamber) through three swirl channels on a swirl insert. Air is supplied to the mixing chamber through the gas inlet tangential to it. Both the air and water are swirled in the same direction. Swirl of liquid is reinforced and finally the mixed fluid flows away from the orifice.
In other more complex solutions, such as the one disclosed in U.S. Pat. No. 5,732,885 A, atomization is carried out in three stages. The first stage is carried out by means of a single liquid orifice and an expansion chamber containing an impingement pin. A high velocity stream of liquid is discharged through the liquid orifice and is broken-up upon striking the flat end of the impingement pin. The second stage is produced by an air guide which reduces in area to form jets of air into a high velocity annular air curtain, the curtain passing through the liquid orifice in surrounding relation with the liquid stream and striking the broken-up flow of the first stage to atomize the particles. The mixture is then allowed to expand in the expansion chamber to reduce the tendency of the liquid particles in the atomized mixture from commingling together and reforming into larger particles. The third stage is effected by the expansion chamber and by multiple discharge orifices. The mixture is sprayed from the expansion chamber through the multiple orifices and, upon being discharged into the atmosphere, the particles are atomized further due to the release of pressure formed inside the expansion chamber.
In yet another example, such as the one disclosed in U.S. Pat. No. 6,267,301 B1, flat spray patterns are achieved by including a pair of longitudinally extending air passageways on opposite sides of a central liquid flow stream discharge orifice. The air flow passages each have a discharge orifice defined by a respective transverse deflector flange and a closely spaced inwardly tapered deflector surface which cooperate to deflect and guide pressurized air streams inwardly toward the discharging liquid flow stream for atomizing the liquid and for directing it into a well-defined spray pattern.
However, no solution known in the state of the art can satisfy both conditions simultaneously. For example, twin-fluid nozzles are capable of producing sprays of small droplet sizes and low liquid flow rates while hydraulic nozzle design can produce large flow rates with relatively large droplets. Furthermore, nozzles in the state of the art present a fixed geometry, previously designed for a fixed atomizing problem (i.e. a given input flow of a either a single liquid or a predefined liquid combination). If the output flow and/or droplet size is not optimal, the user does not have the option of reconfiguring the nozzle for its optimization. In the same manner, when the substance or combination of substances being atomized changes, the user cannot adapt nor optimize the nozzle behaviour for the new scenario.
Therefore, there is still the need in the state of the art of a nozzle capable of adapting and optimizing flow rate and droplet change when varying the number or nature of the substances being atomized (e.g. changing fluids, multiple fluids simultaneously, solid particles . . . ).
The current invention solves all the aforementioned problems by disclosing a modular atomizing nozzle with interchangeable modules, substantially disk-shaped, with different inner shapes and sizes capable of adapting to varying number and type of spraying substances. The nozzle comprises at least:
Depending on the swirling technique and the inlet connection, several preferred mixing schemes can be arranged within the cavities of the stacked modules. Note that said preferred mixing schemes may be arranged within a same embodiment of the invention by choosing a particular sub-set of interchangeable modules. Alternatively, an embodiment of the invention may be adapted to implement a single mixing scheme, being the particular sub-set of selected modules adapted to configure the particular chamber and/or conduct dimensions of said scheme.
In a first preferred mixing scheme, the swirl module comprises a first axial conduct and at least a second slanted conduct (there being typically a plurality of said slanted conducts). That is, there is a relative angle between both conducts greater than or equal to 0° and smaller than or equal to 90° (typically, approximately 45°, although the angle, dimension, number and/or layout of the conducts may vary between embodiments or between interchangeable swirl modules of a same embodiment). Preferably, the first inlet is located on the first housing and is adapted to pass through the first mixing chamber, connect to the first axial conduct, and feed the first liquid directly to the second mixing chamber. In this scheme, the second inlet is fed to the first mixing chamber, and enters the second mixing chamber through the at least one slanted conduct. Also preferably, the nozzle comprises a third inlet located on the second housing, which connects to the second mixing chamber in a direction substantially perpendicular to the first inlet.
In a second preferred mixing scheme, the swirl module comprises a swirl disk with a plurality of slanted lateral conducts which connect the first mixing chamber and the second mixing chamber. The first inlet is preferably located in the first housing, but unlike in the first preferred mixing scheme, the first inlet is more preferably connected directly to the first mixing chamber. The second inlet is preferably located on the second housing and is connected directly to the second mixing chamber. Preferably, the third inlet is connected directly to the nozzle outlet in a direction substantially perpendicular to said outlet.
In a preferred option, independent of the implemented mixing scheme, the first housing, the second housing and the plurality of interchangeable disk-shaped modules are manufactured in two quasi-symmetric halves that are then assembled together along a meridian plane of the nozzle. The two halves are quasi-symmetric, with a symmetry plane defined by the first inlet and second inlet. This enables an easier manufacture, assembly and installation, specially when nozzles of a small size are required.
With the disclosed modular nozzle, the user is therefore able to adapt the mixing scheme and/or the particular dimensions and configurations within a given scheme. This enables said user to optimize droplet size and output flow for a given atomizing scenario (i.e. the particular number, nature and input flow of substances being atomized), as well as to adapt a single nozzle to different scenarios (e.g. when the same nozzle is used to atomize several kinds of liquids or when an additional liquid and/or solid substance is incorporated). Furthermore, the nozzle can work with chemical solutions, solid particles and high pressures. Even in scenarios when severe erosion and abrasion are expected, especially at passageways in the small cross-section areas, the modular design enables to replace the damaged elements without modifying the rest. Additional advantages and features of the invention will become apparent from the detailed description that follows and will be particularly pointed out in the appended claims.
For the purpose of aiding the understanding of the characteristics of the invention, according to a preferred practical embodiment thereof and in order to complement this description, the following figures are attached as an integral part thereof, having an illustrative and non-limiting character:
The matters defined in this detailed description are provided to assist in a comprehensive understanding of the invention. Accordingly, those of ordinary skill in the art will recognize that variation changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In particular, note that any particular embodiment or feature of the device of the invention may be applied to the method of the invention and vice versa. Also, description of well-known functions and elements are omitted for clarity and conciseness.
Note that in this text, the term “comprises” and its derivations (such as “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.
In the context of the present invention, the term “approximately” and terms of its family (such as “approximate”, etc.) should be understood as indicating values very near to those which accompany the aforementioned term. That is to say, a deviation within reasonable limits from an exact value should be accepted, because a skilled person in the art will understand that such a deviation from the values indicated is inevitable due to measurement inaccuracies, etc. The same applies to the terms “about” and “around” and “substantially”.
Note that in the following embodiment descriptions “upper”, “lower”, “vertical” and “horizontal” and any other term referred to relative position assumes that the vertical direction is defined by the main axis of the nozzle, with the first inlet being considered the uppermost position and the outlet being considered the lowermost position. That is, in order to facilitate the understanding of the description and figures, the “first housing” is also referred to as “upper housing”, the “second housing” is also referred to as “lower housing”, the “first mixing chamber” is referred to as “upper mixing chamber”, the “second mixing chamber” is referred to as “lower mixing chamber”, the “first conduct” is referred to as “vertical conduct” and the “second conduct” is referred to as “slanted conduct”. It should be noted, however, that the nozzle may operate in any other orientation or position.
Also note that in the following embodiment descriptions, the “first inlet” is referred to as “liquid inlet”, the “second inlet” is referred to as “air inlet” and the “third inlet” is referred to as “solid particle inlet”. Nevertheless, this nomenclature is only meant to facilitate the understanding of the device operation, without limiting the type of substance introduced through each inlet. For example, in particular embodiments, additional liquids or suspensions could be introduced through the second inlet and/or third inlet. Furthermore, additional inlets for liquid, air, solid particles or any combination thereof could be added in particular embodiments of the invention by including the appropriate inlet inserts, reconfigurable modules and inputs in the upper and/or lower housing.
In the particular embodiment of
Notice that a given embodiment of the invention may comprise a plurality of interchangeable liquid inlets (10), air inlets (50) and/or solid particle inlets (80). Also noticed that, as previously mentioned, the type of substances introduced through each inlet may vary depending on particular embodiments of the invention.
Furthermore, the housing means comprise:
Finally, the nozzle comprises the following stackable disk-shaped modules, with an outer radius that fits the inner radius of the housing means:
In the first nozzle configuration, the liquid inlet (10) comprises a longer cylindrical channel which, when introduced through the inlet ring (30), goes through the upper mixing chamber (200), reaches the vertical conduct (63) of the swirl module (60) and connects with the lower mixing chamber (210). The air inlet (50) is connected to the upper mixing chamber (200), being the upper mixing chamber (200) and lower mixing chamber (210) connected through a plurality of slanted conducts (64). The slanted holes are preferably located around the vertical conduct (63) with a constant angular separation (e.g., three slanted conducts around a single vertical conduct (63) conforming 120° sectors). The slanted conducts (64) are preferable combined with the vertical conduct (63) within the swirl module (60) itself in a lower cavity. Finally, the solid particle inlet (80) is connected horizontally to the lower mixing chamber (210).
In the second nozzle configuration, the liquid inlet (10) comprises a shorter cylindrical channel which is directly connected to the upper mixing chamber (200). Note that the upper mixing chamber (200) is shorter than in the previous case, being conformed only by the inlet ring (30) without the need of an upper mixing chamber module (40). On the other hand, the lower mixing chamber (210) is higher than in the previous case, requiring one or more auxiliary modules (150) which merely comprises an axial cylindrical cavity with the same width as the lower mixing chamber (210). The upper mixing chamber (200) and lower mixing chamber (210) have the same width and are connected through a swirl disk (61) with a plurality of slanted lateral conducts (62) which induce liquid and air swirling improving mixing. Note that air inlet (50) is connected horizontally to the lower mixing chamber (210) whereas two separate solid particle inlets (80) are connected directly to the nozzle outlet (110). In this second nozzle configuration, liquid and gas spin in different direction before they bump into each other, making the interactions between the gas and the liquid more intensive.
The operation of the third nozzle configuration is similar to the first nozzle configuration, with the modules presenting slightly adapted geometries to improve sealing and substance introduction. For example, note that upper protrusion of the inlet ring (30) is no longer present, as the liquid inlet (10) is directly connected to the upper housing (20). Also, the lateral orifice of the lower mixing chamber module (70) presents two segments with different widths, so the solid particle inlet (80) does not connect directly to the lower mixing chamber (210) but gets attached to a middle position of the lateral orifice instead. Furthermore, the tips of the liquid inlet (10), the air inlet (50) and solid particle inlet (80) present slanted corners for improved sealing, as will be further detailed in
Finally, note that the materials of the different components may be adapted depending on the substances being atomized and other factors such as temperature range and corrosion. Some viable materials include nozzles include brass, bronze, cast iron, stainless steels, nickel-based alloys to a wide range of plastics. More particularly, in scenarios where chemical resistance and abrasion resistance are required, due to the presence of decontamination agents and solid particles (e.g. metallic oxides—FeO, Al2O3 and ceramic materials—Si3N4, SiC), the following materials are recommended: hardened stainless-steel, hard alloys (Cobalt alloy 6), Tungsten carbide and ceramics (Silicon carbide, Boron carbide). For example, in a first preferred embodiment, ceramic materials are used for nozzle outlet (110), nozzle pin (90) and solid particle inlet (80), whereas stainless steel is used for the rest of the components. In another example, Aluminum alloys may be used.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17382233.9 | Apr 2017 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/077929 | 10/31/2017 | WO | 00 |
