EP4368296A1

EP4368296A1 - Multi-channel mist head

Info

Publication number: EP4368296A1
Application number: EP22020555.3A
Authority: EP
Inventors: Jerzy Z. KLIMKOWSKI; Wojciech Skrzeszewski
Original assignee: Veromist Ltd
Current assignee: Veromist Ltd
Priority date: 2022-11-14
Filing date: 2022-11-14
Publication date: 2024-05-15

Abstract

Multi-channel mist head for spraying liquids, especially of a two-phase mixture, comprising a supply stem and a dome conjoined and leakproof, provided with internal channels ending with egress ducts, according to the invention, is characterized in that the dome is equipped with one central channel located along the axis of symmetry d-d of the dome and at least two side channels separate from the axis of symmetry d-d of the dome, the central channel and each side channel, comprising, from the side of the supply channel of the supply stem, a cylindrical segment that passes into a conical taper ended with an egress duct, and at least part of the cylindrical segments is fitted with a stator of a diameter that strictly matches the diameter of said cylindrical segments, the stator comprising a core arranged along the longitudinal axis of said cylindrical segments, and on said core, along a variable pitch helix, at least two identical vanes wound same way relative to the core are placed.

Description

The subject of the invention is a multi-channel mist head for spraying or atomizing liquids, preferably the head is provisioned with a low-pressure mixture of gas and liquid.
The mist head is the exit element of a liquid spraying device connected to a reservoir e.g. a pressure cylinder, holding a liquid e.g. water, here the liquid can be held combined with stored gas pressure or integrated with an external stored gas pressure vessel causing said liquid displacement from the reservoir and through the siphon tube, so that the mist is effectively generated.
Devices for spraying liquids known to date are outfitted with a dispersion head with at least one exit, the so-called exit nozzle, and a siphon tube working in tandem with the head via a connector to the main valve located inside the supply vessel. The valve head can be equipped with a diverse range of fit-out, e.g., a socket for attaching a hose, or a distinct dispersion chamber in front of the exit nozzle, a pressure gauge with a readout or a safety valve and can have diverse construction.
Devices of this type can be used in pharmacy, cosmetics industries, also as plant spraying devices, disinfecting devices, in construction, dust control, industry (e.g., paint coating), a wide class of fire extinguishing systems, and fire extinguishers are a special case of the device under consideration.
Fire extinguishers containing water or water solutions as an extinguishing medium and compressed gas, where a highly dispersed mist stream is generated, which is useful for extinguishing purposes and meeting the normative requirements for water extinguishers are called mist or water-mist extinguishers. Mist generation can be accomplished in two different ways, i.e. it is possible to dynamically disperse a homogeneous stream or streams of liquid exiting a single-phase provision head, in a process which requires relatively high supply pressures. Or when a two-phase supply is assured (where the gas and liquid supply lines to the head are not distinct) rapid fragmentation of the phase interfaces takes place inside and just aft the dispersion head attaining the level of dispersion comparative to the former case but at the lower pressure of the supplied fluid stream. In the latter case, especially when the head is provisioned directly with a mixture of liquid and gas, it is necessary to develop improved head designs that perform efficiently at reduced pressure and the lowest possible gas demand.
In the patent applications US2020241535A1 and US2014013802A1 examples of improved, effervescent dispersive nozzles were presented. Under condition that the supply two-phase flow is adequate, for such nozzles ratios of consumption of gas to liquid input are usually the lowest possible.
An example of a collision-type dispersive nozzle, where exiting streams are forced to collide, is presented in description of the Polish utility design PL65131 Y1 .
From the international patent application WO2017160173A1 a device ensuring a two-phase flow in a liquid atomiser is known, and it is equipped in its upper part with a discharge control assembly, the device contains at least one egress channel, as well as a plunger tube, placed below this assembly and interconnected with this assembly, the plunger tube having in its lowermost segment an ingress channel, optionally outfitted with a filter to keep away impurities, and interconnected with a discharge control assembly, and further downstream with an egress channel. This device is equipped with a multichannel collision-type nozzle (presented in Fig. 4A to Fig. 4E).
Multi-channel mist head for spraying liquids, especially of a two-phase mixture, comprising a supply stem and a dome conjoined and leakproof, provided with internal channels ending with egress ducts, according to the invention, is characterized in that the dome is equipped with one central channel located along the axis of symmetry d-d of the dome and at least two side channels separate from the axis of symmetry d-d of the dome, the central channel and each side channel, comprising, from the side of the supply channel of the supply stem, a cylindrical segment that passes into a conical taper ended with an egress duct, and at least part of the cylindrical segments is fitted with a stator of a diameter that strictly matches the diameter of said cylindrical segments, the stator comprising a core arranged along the longitudinal axis of said cylindrical segments, and on said core, along a variable pitch helix, at least two identical vanes wound same way relative to the core are placed.
It is advantageous that the dome comprises from 3 to 26 side channels, having the exits of the egress ducts arranged concentrically with respect to the egress duct of the central channel.
It is advantageous that the central channel and the side channels are streamlined on the inside, so that they lack sharp edges at the junction of the cylindrical segment and the conical taper.
It is advantageous that the side channels, outside its cylindrical segment, within the conical taper have a leading axis along a curve.
It is advantageous that the stator comprises 3 or 4 vanes.
It is advantageous that the vanes are streamlined on the downstream side.
It is advantageous that the egress ducts penetrate through a bowl having a spherical shape.
It is advantageous that adjacent vanes of the stator form an inter-vane space conduit, where the ratio of the cross section area of the inter-vane space conduit at the narrowest point of the inter-vane space conduit to the cross section area of the inter-vane space conduit on the upstream side, near the supply channel, is at least 1: 2, and the cross section area of the downstream inter-vane space conduit is no less than the cross section area of this inter-vane space conduit at its narrowest point.
It is advantageous that the longitudinal axes of the cylindrical egress ducts penetrate through the bowl of the dome are parallel or divergent to each other.
It is advantageous that the supply stem is outfitted with a crimping shank, or a threaded shank having an external or internal thread.
It is advantageous that the supply channel, from the side of the dome, forms a funnel-shaped mouth spanning by virtue of its diameter all the side channels.
It is advantageous that the core of the stator, from the side of the egress ducts, comprises a conical streamlined end.
The subject of the invention in an exemplary embodiment is shown in the drawing, where Fig. 1 shows an overview of the head in the first exemplary embodiment, with a supply stem fitted with a crimping shank; Fig. 2 shows an overview of the head in a second exemplary embodiment, with a supply stem fitted with a threaded shank; Fig. 3 shows a cross section of the head of Fig. 1 with a crimping shank; Fig. 4 shows a cross section of the head of Fig. 2 with a threaded shank, Fig. 5 shows a general view of the dome of the head, obliquely, to the upstream side (from the side of the supply stem); Fig. 6 shows a view of the dome of the head, from the upstream side, at the section by the plane b-b marked in Fig. 7; Fig. 7 shows a cross section of the dome of the head, at the section by the plane a-a marked in Fig. 6; Fig. 8 shows a cross section of the first exemplary embodiment of the supply stem; Fig. 9 shows a cross section of the second exemplary embodiment of the supply stem, with a threaded shank; Fig. 10 shows a cross sectional enlarged view of a dome of the head analogous to Fig. 7, where the outline of placement of stators in the internal channels of the head is indicated, in cylindrical segments of said channels; Fig. 10A shows a cross sectional enlarged view of a dome of the head analogous to Fig. 10, but the dome is additionally equipped with a discus and racks inside; Fig. 10B shows a discus and racks seen in the cross sectional view in Fig. 10A, together with one rack presented separately (at the bottom of Fig. 10B); Fig. 11 shows an enlarged stator, with four bowed vanes; Fig. 11A shows the side surface of the stator vanes in a surface expansion form, i.e. the expanded cylindrical surface showing contact of the stator vanes with the cylindrical segment of the internal channel; Fig. 12 shows an enlarged partial cross section of the dome of the head (on the right), where two different conical tapers are shown in detail, the angle of the lateral deflection of the internal channel in the segment of the conical taper, and the radius of curvature of the conical taper of this channel together with a 3D visualization of the dome of the head (on the left side); and Figure 13 shows the head in another embodiment, with more internal channels, and with a different type of supply stem having an internal thread, and the internal channels of the head do not have curved conical tapers.
The present invention embodies a special type of head - a dispersion head which is a system of swirl chamber-type nozzles, intended primarily for effervescent flows, i.e. the gas-liquid mixture supplying the head is highly dispersed, and for the regular operation of this head the supply pressure of a two-phase mixture in the range from 3 to 20 bar is sufficient, which is the range of operation of dispersion heads referred to as "low pressure". The head is a system of swirl chamber-type nozzles, i.e., the streams inside the individual channels formed in the inter-vane space conduits of the head move along a helical line to create a strong, unstable vortex aft the stator inside the conical cavity of the taper. In the area of the egress ducts a stream of mist is generated both, by the centrifugal force leading to a further fragmentation of the interface, and directly by the mechanism of eruption of fine gas bubbles contained in the mixture. The head has an improved design based on the special arrangement and shape of the internal supply channels and the advanced design of the stator structure.
The multi-channel mist head for spraying liquids, provisioned directly with a fine mixture of liquid and gas, including a supply stem and a sealed dome thereon provided with internal pass-through channels, terminated with egress ducts reaching the face of the dome, according to the invention, is characterized in that the circular in cross section dome 1 (cross-section perpendicular to the longitudinal axis d-d of the symmetry of the dome), including the body 5 and the face, especially in a form of a spherical bowl 3, contains in said body 5 several internal pass-through channels, each of them with a variable cross section, i.e. one central channel 10, having an egress duct 4 in the center of a flat, curved or multi-surface bowl 3, located along the symmetry axis d-d of the dome 1, and at least two side channels 11, separate from the d-d axis of symmetry of the dome 1 by a certain distance and also terminated on the outflow side by egress ducts 4 with exits. The longitudinal axes of cylindrical egress ducts 4 are perpendicular to the outer surface of the bowl 3. The arrangement of the exits of the egress ducts 4 on the bowl 3 may be defined by concentrically arranged circles on the surface of the bowl 3. The central channel 10 is then placed in the center of the bowl 3 and in the center of several e.g., 2, 3 or 4 circles, with the side channels 11 placed on their circumference. The number of side channels 11 may be from 2 to 26, for example from 6 to 20. The amount and the location of the egress ducts 4 on the bowl 3 must assure an even and spatially organized plume of the generated mist.
The head according to the invention comprises a dome 1 and, on the side of the supply tank, tightly connected to it or fixed in it a supply stem 2, which includes a supply channel 8 ending on the downstream side, widened in relation to the supply channel 8, with a funnel-shaped mouth 9, spanning, in terms of its size, specifically: adjusted in diameter and depth, all the side channels 11, and thus ensuring an even provisioning of the central channel 10 and the side channels 11 in the dome 1 of the mist head. The transition of the supply channel 8 into the funnel-shaped mouth 9 is axially located, and in the exemplary embodiment, it is profiled, lacking sharp edges. Designed within the body 5 of the dome 1, adjacent to the funnel-shaped mouth 9 at the basis of the central channel 10 and side channels 11, there is a concave accumulator 16 (concave to the upstream side), which ensures even distribution of the supply stream among individual channels, i.e. the central channel 10 and side channels 11.
The leak-proof connection of the dome 1 with the supply stem 2 can, as in an exemplary embodiment, be realized by providing the body 5 with a stem flue chamber 17, which is sized and shaped to fit the stem flue 19, i.e., both may for example have a cylindrical shape. Moreover, the supply stem 2 may be provided with an exterior stem flange 20 located upstream the stem flue 19. The stem flange 20 also has, cut in the body 5, a stem flange chamber 18, of a matching shape and size. In an exemplary embodiment, the stem flange 20 and a stem flange chamber 18 have closely fitting cylindrical shapes. In the area of the stem flue chamber 17 and the stem flange chamber 18, suitable gaskets, sealing lips or threaded or adhesive joints, or clasps or clamps that respond to a holding pressure, or actuated by rotation of the dome 1 relative to the supply stem 2 can be added. It will be obvious to a person skilled in the art how to achieve a tight and resilient connection of the dome 1 to the supply stem 2. The supply stem 2 is also provided with means of fixture for connecting it to a liquid fire medium supply source, and, in the exemplary embodiment, it is a crimping shank 6 with grooves for tight fitting a rubber hose on it or a threaded shank 7 which includes an external or internal thread for screwing a suitably threaded supply end.
The central channel 10 and the side channels 11 placed in the dome 1 have a particularly designed shape tapering towards the exit. On the upstream side, the body 5 has a cylindrical segment of the central channel 14 and a cylindrical segment of the side channel 15, and then in the downstream direction, the cylindrical segments of the central channel 14 and the cylindrical segments of the side channel 15 extend smoothly starting from said cylindrical segment walls, respectively, as the conical taper of the central channel 12 and as the possibly curved conical taper of the side channel 13, then each of ends with an egress duct 4, for example drilled in the body 5, so that these egress ducts 4 have a form of short cylinders abutting the tops of the conical tapers of the central channel 12 and the conical tapers of the side channel 13.
The central channel 10 has a longitudinal axis of symmetry passing through the egress duct 4, while the side channels 11 preferably do not have such an axis of symmetry. It will be obvious to a person skilled in the art that it is the best for the central channel 10 and the side channels 11 also to have a circular cross section in their conical fragments, but in the actual implementation there are however limitations due to the method of manufacture of these central channels 10 and side channels 11. In the exemplary embodiment, as shown in Fig. 12, the c-c axis in the curved conical taper of the side channel 13 is drawn along the segment of a circle with radius r connecting the axis of the cylindrical segment of the side channel 15 to the desired location of the base of the egress duct 4. Fig. 12 shows the shape of the conical taper of the central channel 12 and of the curved conical taper of the side channel 13 in a figurative form - as divided into skeleton circles with radii gradually decreasing towards the egress duct 4, these skeleton circles being placed on planes perpendicular to the axis d-d of the central channel 10 and the curved axis, respectively c-c in the side channel 11.
In the exemplary embodiment, all the egress ducts 4 orientated along the extensions of the curved axes of the side channels 11 are divergent, so that the egress ducts 4 assure a divergent direction of the mist streams being produced. In turn, the egress duct 4 of the central channel 10 provides the axial direction of the mist, i.e., along the d-d axis of symmetry of the dome 1.
The improvement of the head design consists, as well, in fastening stators 21 at least in part of the internal channels including the central channel 10 and side channels 11, in their cylindrical segments 14, 15. Stators 21, which are multi-helical elements, matching in diameter and length to the diameter and length of these cylindrical segments 14, 15, transform the oncoming axial flow into a vortex created to the downstream side of each stator. In this way, in the conical taper cavity of the central channel 12 and the conical taper cavity of the side channel 13 swirl chambers are created. Each stator 21 aligned with the longitudinal axis of said cylindrical segment of the central channel 14 and/or cylindrical segment of the side channel 15 comprises a longitudinal core 22 along the axis b-b shown in Fig. 11, for example in the form of a stake having a flat base on the upstream side and a tapered or streamlined end 25 on the downstream side. On the core 22, at least two identical profiled (variable-thickness) vanes 28 are positioned down a variable pitch helix, for example three or four vanes 28, equally wound relative to the core 22. The profiled vane 28 thickness is defined as the distance between the left surface of the vane 26 and the right surface of the vane 27 and is variable, i.e. the profiled vanes 28 are tapered towards the b-b axis of the core 22 - have a curvilinear-conic structure, and are intended to create optimal conduits in the inter-vane space conduit. On the upstream side (from the bottom in Fig. 11A), the profiled vane 28 is as thin as possible and cut perpendicularly and flush with the base of the core 22 as shown in Fig. 11.
The lower (upstream) portion of the left surface of the vane 26 and the right surface of the vane 27 are approximately parallel to each other, if possible, tilted from 0 to 20°, preferably less than 15° away from the direction of the incoming fluid (this is the deviation of the f-f axis with respect to the e-e axis in Fig. 11A), while in the downstream part both surfaces form a wedge (from the top in Fig. 11A) because the incidence angle is significantly different between these surfaces (see the g-g axis in Fig. 11A), each is at an acute angle. The upper (downstream) side of the vane 28 is arched, because the trailing edge of the vane 28 is designed in the shape of a wedge, where due to the incidence angle of the left surface being almost 90° said wedge is bent downward to limit the flow resistance behind the stator 21.
In addition, each vane 28, on the upstream side, is optionally provided with interference locking cogs 24 anchoring the entire stator 21 in the cylindrical segment of the central channel 14 or the cylindrical segment of the side channel 15. The anchoring may consist of pressing a sharp edge of the interference locking cog 24 into the material of the dome 1 adjacent to the stator 21 in this region.
In another embodiment of the invention (shown in Fig. 10A and 10B) it is possible to mount and stabilize the stators 21 differently. The dome 1 of the head is an element separate from the stator 21, therefore in order to save on labour cost and take advantage from the 3D printing technology, it may prove beneficial to amalgamate all the stators 21 onto a common base in the form of discus 29 and place this combined element approximately where the b-b line is presented in Fig. 10, between funnel-shaped mouth 9 and the central channel 14 and the side channels 15 of the dome 1. Therefore, all the stators 21 are placed above the discus 29, where the cylindrical sections of the central channel 14 and the side channels 15 of the dome 1 are extended. The discus 29 has the same number of channels as the number of internal channels (central channel 14 and the side channels 15) in the dome 1 and the diameters of channels in the discus 29 are the same as the diameter of the corresponding internal channels in the dome 1. The channels in the disk are matched in position to the position of the corresponding internal channels of the dome 1. In the space of discus 29, in each channel, a rack 30 (separately shown at the bottom of Fig. 10B) is integrated to support the corresponding stator placed above it. Rack 30 has axial and straight vanes, which abut smoothly the lower edges of the vanes 28 of the stator 21. Side wall of the discus 29 is slightly inclined and the vanes of the rack 30 (only vanes adjacent to this side wall of the discus 29) are made to protrude this side wall of the discus 29. As a result, protrusions 31 are formed. When pressed, these protrusions 31 anchor the combined stators 21 and discus 29 element in the cylindrical segments of the internal channels of the dome 1, same as the interference locking cogs 24 anchor each stator 21 in the cylindrical segment of the central channel 14 or the cylindrical segment of the side channel 15 in the earlier embodiment presented above. When the discus 29 with racks 30 is used in the head according to the invention, the size and/or placement of the adjacent elements i.e. stem flue chamber 17, concave accumulator 16 and funnel-shaped mouth 9 are modified accordingly.
In the stator 21 the supply stream is divided so that the individual streams gain an angular velocity, and each of them leaves this inter-vane space conduit approximately in the direction forced by the g-g axis orientation.
The variable pitch of the helical line defining the inter-vane space conduits and the increase in the thickness of the vanes 28 downstream toward the point where a "throat" is formed (the narrowing of the width i shown in Fig. 11A) in the inter-vane space conduit, means, that in this area a decreasing cross section of the inter-vane space conduit, formed between adjacent vanes 28 and additionally confined by the core 22 and adjacent to the vanes 28 walls of the cylindrical segments 14, 15, is attained (as shown schematically by the arrows in Fig. 11A). Whereas Fig. 11A also illustrates the thickness of each vane 28, i.e. the footprint of the lateral surface of the vane 28 resulting from the contact surface of the stator vanes 28 with the cylindrical segment 14, 15 of the central channel 10 or side channel 11. The ratio of the cross sectional area (perpendicular to the hypothetical axis of this inter-vane space conduit), at the narrowest point of the inter-vane space conduit (the so-called "throat" - a constriction) to the cross-sectional area of this space on the ingress side (width h shown in Fig. 11A), near the supply channel 8, is at least 1: 2, for example, it is from 1: 2 to 1: 8, and is 1: 3, 1: 4, 1: 5, 1: 6, 1: 7 or 1: 8.
At the same time, the cross-sectional area of the downstream inter-vane space conduit is not less than the cross-sectional area at the "throat", and preferably, the cross-sectional area of the downstream inter-vane space conduit is greater than the cross-sectional area at that constriction.
The vanes 28, and consequently also the helix defining the inter-vane space conduits, can be right-handed as shown in Fig. 11, but can also be left-handed.
The stator 21 may optionally be slightly wider at the base, in the upstream portion, to be press-fitted in the cylindrical segment of the central channel 14 and cylindrical segment of the side channel 15. The widened base of the stator 21 and optionally the interference locking cogs 24 ensure effective fastening of the stator 21 at the seat.
For the purposes of the present invention, the upstream side is the bottom side in the figures and the downstream side (mist plume exit) is the top side in the figures, where the terms "upper" or "lower" are used in this specification to follow the convention described.
Fig. 1 shows the head in the first embodiment of the invention, where the dome bowl has a spherical shape and all the egress ducts are cut through this one, common, spherical shell of the bowl, along with an indicated curved side channels allowing for a divergent (non-collision) layout of the individual streams coming out from the egress ducts, and thus the mist streams generated in the side channels of the head similarly diverge one from the other.
Fig. 12 shows the cross section of the dome with the central channel oriented axially with respect to the head body (along the marked d-d axis), and the egress duct of the side channel is deviated from this axis by an angle β ranging from 10° to 45°, especially from 15° to 30°, such as from 18° to 21°. As shown in Fig. 12, the cylindrical segments of all internal channels are oriented parallel to the d-d axis of the head.
Another embodiment of the invention is also possible, in which some, or all the egress ducts together with the internal channels of the dome are oriented parallel to each other and may have axially symmetric conical tapers or curved conical tapers, and this is also a non-collision arrangement. At the same time, it is possible for some of the internal channels to have cylindrical segments oriented parallel to the d-d axis of the head, and to some at an acute angle to this axis.
Fig. 13 shows an embodiment of the invention where only a part of the internal channels in their cylindrical segments are mutually parallel and extend in the direction of the axis d-d of the head. The illustrated dome bowl contains a flat central surface surrounded by a second, oblique circumferential surface, the extremity of which is lowered from the central flat surface. In such an embodiment, some or all the side channels may be shaped like a central channel, i.e., they may have a longitudinal axis of symmetry extending through the cylindrical segment of the channel, and further through a conical taper as far as the egress duct (symmetrical channel). This variant of the invention may not require the conical tapers of the inner side channels to be curved, i.e., there will be no channels with a curve-guiding axis c-c as shown in Fig. 12.
As shown in Fig. 13, the flat central surface of the bowl contains one central channel and six symmetrically positioned side channels around the central channel, all seven channels being identical in shape, and curved-profile channels are absent in this area. The cylindrical segments of the internal channels located on the oblique, circumferential surface of the bowl, are placed at an acute angle of up to 45° in relation to the aforementioned d-d axis of the head. In such a case, the angle β described above (see Fig. 12) may be even greater than 30°, e.g., from 10° to 60°, or from 30° to 45°.
There is also no curved conical taper in these internal channels. Such a variant of the invention also assures non-collision generation of mist originating from individual channels, and the modification of the bowl surface allows all channels to be symmetrical in their shape, without any curvature in the upper, conical taper part. Thus, divergent (non-collision) mist jets can be generated in the head according to the invention in both above-described ways. The discrepancy in the layout of the individual mist streams coming out of the head channels should be understood as the mutual positioning of the axes of the egress ducts being parallel or divergent.
The head according to the invention comprises refined pass-through internal channels, modified by inserting a specific-type stator, but it does not have to include only such channels. It may also include other types of channels, without stators, e.g., known channels with a typical structure, e.g., symmetrically conical tapering along their entire length until reaching the egress openings.
Thus, the head according to the invention may comprise a combination of the refined channels according to the invention and other channels, being advisable that e.g., channels of a known type be arranged e.g. in pairs symmetrically, alternating with the refined channels, or alternating in concentric circles: on one circle just one type of channels, and another type of channels on the other circle, etc.
The mist head according to the invention has a specific, improved structure and works as an effervescent nozzle, but it generates mist even in the regime when, due to an increased concentration of gas in the two-phase flow, there is virtually no proper liquid supply to the head and ensures proper performance with single-phase provision at pressures above 8 bar.
In order to ensure the effective operation of the head throughout the entire discharge of the liquid spraying device, the following improvements have been introduced: a) internal channels are designed as rounded throughout in their entire space, b) egress ducts are designed in a non-collision arrangement, i.e. the component mist streams generated in each channel do not collide with each other, and at the same time a widened mist plume is provided, c) at least some of the channels are provided with a stator which divides the supply stream and then drives the component streams in a helical motion, with the stator over the predominant segment amounting to at least 3/4 of their run has tapered intra-vane conduits to improve the quality of the mist being produced.
Thus, in order to satisfy the regime of a reduced pressure combined with a requirement to preserve the lowest possible gas demand the process leading to obtaining a high dispersion rate of the mist plume is organised in several stages inside the body of the dispersion head; first, the liquid stream is divided into individual streams upon entering different channels of the head, then, each individual stream is further subdivided upon entering separate conduits of the inter-vane spaces - formed by the stator vanes and the wall. Next, subjected to the action of the stator and its vanes, the medium accelerates significantly until passing through a narrowed in relation to the channel width throat (constriction), and gains a significant angular velocity component, therefore upon exiting the inter-vane spaces individual tributaries converge and just aft the vanes primarily by way of warping and stretching the interface (by distorting the gas bubbles) a very intense fragmentation of the interface takes place while a highly unsteady self-constricting vortex of refined phase mixture rushes towards the egress duct. Finally, within the area egress duct the droplets of the mist stream undergo a final breakdown under the action of both, the centrifugal force and the eruption of fine gas bubbles contained in the mixture.
The head according to the invention can be used in several types of devices, in particular fire extinguishers, e.g., in diverse types of mist extinguishers.

Designations in the drawings:

1 - dome
2 - supply stem
3 - bowl
4 - egress duct
5 - body
6 - crimping shank
7 - threaded shank
8 - supply channel
9 - funnel-shaped mouth
10 - central channel
11 - side channel
12 - conical taper of the central channel
13 - conical taper of the side channel
14 - cylindrical segment of the central channel
15 - cylindrical segment of the side channel
16 - concave accumulator
17 - stem flue chamber
18 - stem flange chamber
19 - stem flue
20 - stem flange
21 - stator
22 - core
23 - the lateral surface of the vane
24 - interference locking cogs
25 - streamlined end of the core
26 - left surface of the vane
27 - right surface of the vane
28 - vanes
29 - discus
30 - rack
31 - protrusion
h - width of the inter-vane space conduit to the upstream side
i - width of the constriction of the inter-vane space conduit
b-b - axis - longitudinal axis of the stator
c-c - axis - curved axis of the side channel
d-d - axis - longitudinal axis of symmetry of the head and dome (at the same time the axis of the central channel)
e-e - axis - axis parallel to the direction of the supply fluid flow
f-f - axis - approximate direction of the stream in the upstream segment
g-g - axis - approximate direction of the outflowing trail-stream in the downstream segment
β - angle - deviation angle of the axis of the egress duct of the side channel in relation to the axis of symmetry d-d
r - radius of the rounded curvature of the curved conical taper

Claims

Multi-channel mist head for spraying liquids, especially of a two-phase mixture, comprising a supply stem and a dome conjoined and leakproof, provided with internal channels ending with egress ducts, characterized in that the dome (1) is equipped with one central channel (10) located along the axis of symmetry d-d of the dome (1) and at least two side channels (11) separate from the axis of symmetry d-d of the dome (1), the central channel (10) and each side channel (11), comprising, from the side of the supply channel (8) of the supply stem (2), a cylindrical segment (14, 15) that passes into a conical taper (12, 13) ended with an egress duct (4), and at least part of the cylindrical segments (14, 15) is fitted with a stator (21) of a diameter that strictly matches the diameter of said cylindrical segments (14, 15), the stator (21) comprising a core (22) arranged along the longitudinal axis of said cylindrical segments (14, 15), and on said core (22), along a variable pitch helix, at least two identical vanes (28) wound same way relative to the core (22) are placed.
The head according to claim 1 characterized in that the dome (1) comprises from 3 to 26 side channels (11), having the exits of the egress ducts (4) arranged concentrically with respect to the exit of the egress duct (4) of the central channel (10).
The head according to claim 1 or 2, characterized in that the central channel (10) and the side channels (11) are streamlined on the inside, so that they lack sharp edges at the junction of the cylindrical segment (14, 15) and the conical taper (12, 13).
The head according to claim 1, 2 or 3, characterized in that the side channels (11), outside its cylindrical segment (15), within the conical taper (13) have a leading axis along a curve.
The head according to any of the claims 1 to 4, characterized in that the stator (21) comprises 3 or 4 vanes (28).
The head according to any of the claims 1 to 5, characterized in that the vanes (28) are streamlined on the downstream side.
The head according to any of the claims from 1 to 6, characterized in that the egress ducts (4) penetrate through a bowl (3) having a spherical shape.
The head according to any of the claims 1 to 7, characterized in that adjacent vanes (28) of the stator (21) form an inter-vane space conduit, where the ratio of the cross section area of the inter-vane space conduit at the narrowest point of the inter-vane space conduit to the cross section area of the inter-vane space conduit on the upstream side, near the supply channel (8), is at least 1: 2, and the cross section area of the downstream inter-vane space conduit is no less than the cross section area of this inter-vane space conduit at its narrowest point.
The head according to any of the claims 1 to 8, characterized in that the longitudinal axes of the cylindrical egress ducts (4) penetrate through the bowl (3) of the dome (1) are parallel or divergent to each other.
The head according to any of the claims 1 to 9, characterized in that the supply stem (2) is outfitted with a crimping shank (6), or a threaded shank (7) having an external or internal thread.
The head according to any one of claims 1 to 10, characterized in that the supply channel (8), from the side of the dome (1), forms a funnel-shaped mouth (9) spanning by virtue of its diameter all the side channels (11).
The head according to any one of claims 1 to 11, characterized in that the core (22) of the stator (21), from the side of the egress ducts (4), comprises a conical streamlined end (25).