EP0227715B1

EP0227715B1 - Atomizer

Info

Publication number: EP0227715B1
Application number: EP86903285A
Authority: EP
Inventors: Henrik Holm Jensen
Original assignee: DANFOIL AS
Current assignee: DANFOIL A/S
Priority date: 1985-06-24
Filing date: 1986-06-23
Publication date: 1993-03-24
Anticipated expiration: 2006-06-23
Also published as: DK283685A; DE3688127T2; DK155175C; ATE87232T1; DK283685D0; WO1987000078A1; AU5994086A; DE3688127D1; EP0227715A1; DK155175B

Abstract

An atomizer for atomization of a first fluid within another fluid is of the kind where in a channel, which guides the second fluid, a wingshaped atomizer (1) means is comprised with an aperture (4) leading from one flat side of the wingshaped atomizer means tothe other flat side (11, 11A, 12, 12A) thereof, and where the wingshaped means comprises at least one through channel which from a side wall opening in the through aperture (4) extends to a supply channel or to a tube means for the supply of the first fluid to the atomizer, and where the wingshaped atomizer means at the through aperture (4), preferably at the side (9) which is orientated away therefrom from the direction of flow of the second fluid and preferably being present at both of the flat sides of the wingshaped means, has a smaller wing thickness (11A, 12A) of the wingshaped means and comprising a towards the through aperture orientated rounded off or sharpened wingshape-leading-edge-like edge (9). To achieve a better atomizing, also when only one supply side wall opening in the through aperture (4) is comprised, the through aperture (4) comprises a to the last mentioned edge (9) opposite and in any rate somewhat or mainly oblique positioned side wall (8) of the aperture (4). These (8, 9), connecting the lateral walls (6, 7), may have unequal lengths and may be oblique positioned, just as the outer contours of the wingshaped means (1) completely or partly or for portions thereof may be shaped in conformity with the side walls (8, 9, 6, 7) of the through aperture (4).

Description

The present invention relates to an atomizer comprising an injector member located in a flow channel for atomizing a first fluid into a second fluid flowing through this channel, the injector member having the shape of an airfoil wing member, whereby the leading edge of the wing member is arranged upstream relative to the intended direction of flow of the second fluid, and whereby the said airfoil wing member comprises a through aperture leading from the upper surface to the lower surface, at least one through channel leading laterally from an opening in a side wall of the aperture for connection to a supply channel or to a tube for the supply of the first fluid to the injector member, and whereby at least one of said upper and lower surfaces has an area adjacent the downstream side of the said through aperture which tapers in the direction towards the downstream side of the through aperture to provide the airfoil wing member with a reduced thickness.
It belongs to the prior art as disclosed in US-A-2,770,501 to position such an atomizer within a channel having for instance a square or circular cross section and adapted to guide the second fluid, to which second fluid a first fluid has to be mixed in an atomized state when the first fluid is present as a liquid or vapour and the second fluid is a liquid and then to attain a close mixture of the two fluids or to obtain a dispersion of the first fluid into the second fluid.
To this purpose the wingshaped member, i.e. the airfoil wing member, is positioned within the second fluid stream such that this fluid flows against the leading edge of the wingshaped member and from thereon passes along both upper and lower surfaces thereof, the wingshaped member being positioned transversely and parallel to the direction of flow. The mixture leaves the wingshaped member at the trailing edge thereof. This thinner trailing edge may have a sharpened configuration. In general the wingshaped member extend transversely of the direction of flow from side to side over the full cross sectional width of the channel and is kept in place through pins in the channel side walls. These pins may be tube-shaped and connect to channels in the wing shaped member, these channels leading to the through aperture in the wing shaped member and supplying first fluid into said through aperture, from which aperture the first fluid is spread into the second fluid, particularly along the sides of the wingshaped member.
It belongs to the state of the art to supply the first fluid via two opposing side wall openings into the through aperture in the wingshaped member, equal quantities of the first fluid being supplied simultaneously via these openings per unit of time. In this manner of supplying the first fluid the collision of the two supplied quantities contributes to the atomizing of the first fluid into the second fluid which is passing preferably along both side surfaces of the wingshaped member. By closing one of the side wall supply openings opening into the through aperture, atomizing still takes place but not as effectively, and in case of mixing the fluids or producing a dispersion the efficiency is less than when the first fluid is supplied from both sides into the through aperture.
For practical reasons it is not particularly easy to arrange two equal supply currents of the first fluid meeting each other from opposite directions within the through aperture in the wingshaped member. Supply hoses for the first fluid require space on both sides of the channel. In case, as often is required, more wingshaped means for one and the same fluid are arranged in one and the same channel, or in case where more than one first fluid, each having its own wingshaped member arranged within the second fluid stream, the number of supply tubes or hoses including branching means, present mechanical as well as current technical problems.
It is the purpose of the present invention to provide an embodiment of the wingshaped member by means of which an effective atomization is attained with single sided supply of first fluid into the through aperture in the wing shaped member, wherein basically there is needed only one supply channel for supplying first fluid into the through aperture. However, nothing prevents such fluid to be supplied simultaneously via more wall openings on one side of the through aperture; this multiple supply does not need to be in an equal manner.
This purpose is attained with the characterizing features mentioned in claim 1. Hereby a better mixing of the two fluids is achieved. The modification defined in claim 2 improves the mixing For reasons of viscosity the spacing may decrease.
Generally it is advantageous if the lateral side walls connecting the upstream wall and the downstream edge of the through aperture are shorter than these two aperture boundaries.
By means of the features according to claim 3 a further improvement is attained. The lateral wall with largest extent along the circumference of the through aperture in general is the side wall which does not comprise the supply opening for the first fluid.
By means of the features according to claim 4 the atomization may be further improved.
Dependent on viscosity and adhesion unto the surface of the two fluids it may be advantageous to employ the features which are described in claim 5, to attain improved atomizing or mixing, as the improved fluid run-off at the upper and lower surfaces of the wingshaped means then may be influenced to form small turbulent whirls or to provide flow hindrances or the opposite thereof within the vicinity of these surfaces of the wingshaped means. The oblique form together with the geometrical shape of the through aperture, when supplying the first fluid solely through one side wall of the through aperture, may further improve the atomizing or mixing of the fluids, and to which purpose the features according to claim 6 are effective.
By using embodiments according to claim 7 and/or 8 an atomization may be achieved which is adaptable to possible uneven flows of the second fluid at the upper and lower surfaces of the wingshaped means, whereby the features according to claim 7 provide a symmetrical flow at these two surfaces of the wingshaped means, whereas the features according to claim 8 provide uneven flow conditions of the first fluid along the upper and lower surfaces transversely to the flow of the second fluid.
In this respect further improvements of the atomizing or mixing are attainable by means of the features according to claim 9 and/or by at least one portion of The outer contours of The wing shaped means following on an enlarged scale at least substantially The circumferential contours of the through opening, as a better adaption to such uneven flow along upper and lower surfaces may be achieved transversely to the flow of the second fluid, partly as a result of the structural extent of the through aperture but also partly resulting from the extent of the external contours of the wing-shaped means so that adaptation to uneven flows within the total width of the channel leading the second fluids is possible to a larger extent.
Embodiments according to the invention are described in more detail in the following with reference to the drawing, wherein:

Fig. 1 and 2: illustrate an embodiment of a wingshaped means according to the invention,
fig. 3 and 4: show an alternative embodiment of a wingshaped means according to the invention, and
fig. 5 and 6: illustrate an embodiment of a wingshaped means to be used at unequal conditions of flow for the second fluid especially.

The figures 2, 4 and 6 respectively show the cross sections II-II, IV-IV and VI-VI according to the respective figures 1, 3 and 5.
Within the single figures in the drawing details of the same kind or having corresponding functions carry the same reference numeral.
A wingshaped means for an atomizer according to the invention carries reference numeral 1. The upper flat surface of the wingshaped means is referred to with 11, respectively by 11A, whereas the lower flat surface is referred to with 12, respectively with 12A. 11A and 12A designate depressed surface areas within the wingshaped means and which areas in direction towards a through aperture 4 running from 11, 11A to side 12, 12A are tapering into a sharpened or rounded off downstream side or edge 9 facing the through aperture 4. At the back the wingshaped means 1 terminates in an edge 19 whereas anteriorly the wingshaped means terminates in a curved or sharpened edge 18. Opposite to the sharpened or rounded off edge 9 of the aperture 4 has a side wall 8. Lateral walls 6 and 7 connect as side walls the two walls 9 and 8 of the aperture 4.
Internally in the wingshaped means 1 a channel 10 is running which opens into the lateral wall 6 of the aperture 4. At the other end the channel 10 through a stud 10A is connectable to a first fluid supply. The first fluid flowing through the side wall opening in the later wall 6 the through aperture 4 and mixes with a second fluid which flows along the wingshaped means 1.
The wingshaped means 1 can by means of the stud 10A and of a pin 5 positioned opposite to the stud 10A be held to the side walls of fluid channel not shown in the drawing, in which channel the second fluid is flowing around the wingshaped means 1 in direction from left to right, i.e. in direction from edge 18 to edge 19. The first fluid flows out to both sides from the through aperture 4, and in case the second fluid is gaseous or is a vapor an atomization of the first fluid into the second fluid takes place. This is due to the striking of fluid against the edges of the aperture 4, but is also due to the formation of whirls within this range.
When, as shown in figures 3 and 4, the rear edge 19 is oblique and the edge 19 and is parallel to the edge 9 a better atomizing is attained. The side walls 11, 11A, 12 and 12A may comprise grooves or furrows mainly running to the right hand side in the drawing or diverging to the right in the drawing from the area around the through aperture 4. In many cases the atomizing is hereby improved.
To achieve better atomizing the wingshaped means 1 may have a through aperture 4 with curved side walls and a similar outer contour as illustrated in figure 5.

Claims

Atomizer comprising an injector member located in a flow channel for atomizing a first fluid into a second fluid flowing through this channel, the injector member having the shape of an airfoil wing member, the leading edge of the wing member being arranged upstream relative to the intended direction of flow of the second fluid, and the said airfoil wing member (1) comprising a through aperture (4) leading from the upper surface (11) to the lower surface (12), at least one through channel (10) leading laterally from an opening in a side wall of the the aperture for connection to a supply channel or to a tube for the supply of the first fluid to the injector member, at least one of said upper and lower surfaces (11,12) having an area (11A,12A) adjacent the downstream side (9) of the said through aperture (4) and tapering in the direction towards the downstream side (9) of the through aperture to provide the airfoil wing member with a reduced thickness, characterized in that the or each of the supply channels (10) open in only one side wall of the aperture (4) and in that opposite to the edge of the downstream side wall (9) of the aperture (4) defined by the tapering area(s) the aperture (4) exhibits an upstream side wall (8), wherein the upstream wall (8) and the downstream side (9) are arranged obliquely relatively to one another.
Atomizer according to claim 1, characterized in that the spacing of the upstream wall (8) and the downstream edge (9) increases away from the side wall (6) through which the first fluid is supplied.
Atomizer according to claim 1 or 2 characterized in that the through aperture (4) comprises at least two lateral side walls (6, 7) which connect the aforementioned down stream side wall (9) with the aforementioned up stream side wall (8) and have unequal lengths in direction along the circumference of the through aperture (4).
Atomizer according to claim 3 characterized in that the two lateral side walls (6, 7), as viewed in direction along the circumference of said through aperture (4), are running obliquely relatively to one another.
Atomizer according to claim 1, 2, 3 or 4 characterized in that at least one of the upper and lower surfaces (11, 11A, 12, 12A) comprise grooves or furrows running from the through aperture (4), whereby the performance is improved with these surfaces being totally or partly roughened.
Atomizer according to claim 5 characterized in that the said grooves or furrows are running divergently substantially in flow direction from the area of the through aperture (4).
Atomizer according to claim 1, 2, 3, 4, 5 or 6 characterized in that the side wall surfaces of the through aperture (4), not including the down stream side wall (9) of the through aperture (4), are running substantially perpendicular to the upper and lower surfaces (11, 12).
Atomizer according to any one of the preceeding claims, characterized in that the surfaces of at least one of the walls (6,7,8,9) defining the through aperture (4), when viewed from one of the upper or lower surfaces (11,12) towards the other surface (11,12), exhibits a multiplanar weakly curved surface structure, such as finely prismatically curved, convexedly, concavely or both.
Atomizer according to any one of the preceding claims, characterized in that the through aperture (4) has a polygonal shape with at least four sides including the downstream side (9), at least some of the sides of the polygon being of different length from the other sides.