CA2221897A1 - Liquid atomizing nozzle - Google Patents
Liquid atomizing nozzle Download PDFInfo
- Publication number
- CA2221897A1 CA2221897A1 CA 2221897 CA2221897A CA2221897A1 CA 2221897 A1 CA2221897 A1 CA 2221897A1 CA 2221897 CA2221897 CA 2221897 CA 2221897 A CA2221897 A CA 2221897A CA 2221897 A1 CA2221897 A1 CA 2221897A1
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- Canada
- Prior art keywords
- liquid
- cylindrical chamber
- supplying pipe
- atomizing nozzle
- pressurized air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/02—Spray pistols; Apparatus for discharge
- B05B7/04—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge
- B05B7/0416—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing one gas and one liquid
- B05B7/0441—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing one gas and one liquid with one inner conduit of liquid surrounded by an external conduit of gas upstream the mixing chamber
- B05B7/0475—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing one gas and one liquid with one inner conduit of liquid surrounded by an external conduit of gas upstream the mixing chamber with means for deflecting the peripheral gas flow towards the central liquid flow
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/02—Spray pistols; Apparatus for discharge
- B05B7/10—Spray pistols; Apparatus for discharge producing a swirling discharge
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Abstract
The present invention provides a liquid atomizing nozzle capable of atomizing liquid materials of highly viscous or containing bulky solid materials charged not only at a small feed rate but also at several thousands liter/hr rate, by which the liquid is atomized and sprayed uniformly with a predetermined spray angles. A liquid atomizing nozzle of the invention comprises a liquid supplying pipe; a cylindrical chamber for whirling of air being connected at one end with the liquid supplying pipe, having an inside diameter larger than inside diameter of the liquid supplying pipe, and being provided with one or more through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber; an orifice disposed at the top of the cylindrical chamber and having a circular opening of smaller than inside diameter of the cylindrical chamber; and an external cylinder covering over the cylindrical chamber and at least a part of the liquid supplying pipe and being provided with a pressurized air supplying pipe.
Description
TITLE OF THE INVENTION
Liquid atomizing nozzle BACKGROUND OF THE INVENTION
1. Filed of the invention:
The present invention relates to a liquid atomizing nozzle used in the field of spray drying, humid pelletizing, coating, combustion and the like, and the nozzle is especially suited for atomizing liquid materials having high viscosity or containing bulky solid materials.
Liquid atomizing nozzle BACKGROUND OF THE INVENTION
1. Filed of the invention:
The present invention relates to a liquid atomizing nozzle used in the field of spray drying, humid pelletizing, coating, combustion and the like, and the nozzle is especially suited for atomizing liquid materials having high viscosity or containing bulky solid materials.
2. Description of the prior art:
Liquid atomizing nozzles having compressed air power sources are widely used in such fields of spray drying, coating works of liquid materials. The nozzle is basically composed of a liquid supplying pipe and a compressed air supplying pipe coaxially arranged outside of the liquid supplying pipe. By means of compressed air from the head of air supplying pipe blasting at a high speed in the axial direction, the liquid pushed or sucked outward from the head of liquid supplying pipe is sheared and atomized.
The amount of liquid processed by this kind of coaxial double-pipe liquid atomizing nozzles is usually from several liter/hr to dozens liter/hr, because atomizing features of the nozzles worsens when the nozzle is enlarged analogously in proportion to increased amount of liquid to be processed (increased ratio of compressed air and flattened distribution of atomized liquid particles).
Since an enlarged diameter of liquid supplying pipe worsens the atomizing features, diameters of liquid supplying pipe are set at around 0.5-3.0mm. Accordingly, liquid atomizing nozzles of this type are not suitable for atomizing liquids of so highly viscous as scores of thousands cP (centipoise) or those containing bulky solid materials. Further, atomizing nozzles of this type are too narrow in spray angles to be employed as atomizing equipments of spray dryers that they can not substitute for pressurized spray nozzles having spray angles of larger than 70 degree. For relatively low viscous (below 500 cP) liquids capable of being atomized with pressurized spray nozzles, conventional double-pipe fluid atomizing nozzles require 2-5 times more atomizing energy (kw) than that required by pressurized spray nozzles. This is the reason why large capacity double-pipe fluid atomizing nozzles are not so popular.
SUMMARY OF THE INVENTION
The present invention is directed to provide a liquid atomizing nozzle capable of atomizing liquid materials of highly viscous or containing bulky solid materials charged not only at a small feed rate but also at several thousands liter/hr rate, by which the liquid is atomized and sprayed uniformly with a predetermined spray angles.
The liquid atomizing nozzle according to the present invention comprises a liquid supplying pipe; a cylindrical chamber for whirling of air being connected at one end with the liquid supplying pipe, having an inside diameter larger than inside diameter of the liquid supplying pipe, and being provided with one or more through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber; an orifice disposed at the top of the cylindrical chamber and having a circular opening of smaller than inside diameter of the cylindrical chamber; and an external cylinder covering over the cylindrical chamber and at least a part of the liquid supplying pipe and being provided with a pressurized air supplying pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.1 is a longitudinal section of the liquid atomizing nozzle according to the present invention; Fig.2 is a longitudinal section of the liquid supplying pipe; Fig.3 is a longitudinal section of the cylindrical chamber; Fig.4 is a sectional view seen along A-A of the cylindrical chamber of Fig.3; Fig.5 is a longitudinal section of the orifice; Fig.6 is a view of the orifice of Fig.5 seen from the direction C; Fig.7 is a longitudinal section of the external cylinder; Fig.8 is a longitudinal section of a seal cap; Fig.9 is a longitudinal section of the liquid atomizing nozzle equipped with a reverse conical body and a disc-type liquid distributor; Fig.10 is a side view of the reverse conical body; Fig.11 is sectional view of the orifice used in combination with the reverse conical body; Fig.12 is a top view of the disc-type liquid distributor;
Fig.13 is sectional view along D-D of the disc-type liquid distributor of Fig.12; Fig.14 is a top view of a disc-type liquid revolving plate; Fig.15 is a side view of the disc-type liquid revolving plate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The liquid atomizing nozzle according to the present invention will be explained by reference to the attached drawings.
Reference number 1 indicates the liquid supplying pipe, and the pipe is connected with the cylindrical chamber for whirling of air 2 at one end exemplified by the left end in Fig.l. The cylindrical chamber 2 has a cylindrical shape having inside diameter larger than inside diameter of the liquid supplying pipe l, and is provided at the cylindrical portion with one or more through holes 3 for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber. As shown by Fig.4 by the cross-sectional view, a plurality of the through holes 3 for passing through pressurized air may be disposed along the same circumference (c.f. Fig.4) or in rows in axial direction of the cylindrical chamber (e.g. at A-A and B-B in Fig.3). A plurality of through holes may be arranged along the same circumfere~ce and a plurality of circumferential arrangements may be disposed in rows in the axial direction. The orifice 4 having the circular opening 5 of smaller than inside diameter of the cylindrical chamber is disposed at the head of the cylindrical chamber 2.
Further, the external cylinder 6 is so disposed as to cover the cylindrical chamber 2 and at least a part of the liquid supplying pipe 1, and the pressurized air supplying pipe 7 is connected therewith. Reference number 9 is a seal for sealing the other end of the external cylinder 6, and reference number 8 is a seal cap.
S The liquid atomizing nozzle according to the invention can be assembled easily by steps of inserting the liquid supplying pipe 1 into a connection opening disposed at the bottom of the cylindrical chamber 2; inserting into the external cylinder 6 the cylindrical chamber attached with the liquid supplying pipe;
fastening the orifice 4 to front end of the external cylinder 6 to fasten the front end of the cylindrical chamber 2; engaging the seal cap 8 having a through hole for the liquid supplying pipe 1 at the back end of the external cylinder 6; and turning thus assembled nozzle to air-tight or water-tight by means of applying appropriately sealing materials. Disassembling or exchanging such parts as the cylindrical chamber 2 and/or orifice 4 can be done easily.
Working mechanism of the liquid spray nozzle of the present invention will be explained hereunder. Liquid material supplied into the cylindrical chamber 2 through the liquid supplying pipe 1 is revolved and accelerated in the cylindrical chamber by virtue of the pressurized air coming in at a high speed from the through holes 3 in the direction tangential to circular internal surface of the cylindrical chamber. The accelerated revolving liquid material moves by means of centrifugal force toward internal surface of the cylindrical chamber, turns to thin film, moves toward the circular opening 5, and is sprayed therefrom with accompaniment of whirling air stream. In this case, fine liquid particles are accompanied by air stream ejected into the cylindrical chamber. Other liquid flows in a thin film state along the internal surface of cylindrical chamber, atomized at S the opening 5 of orifice and sprayed.
In conventional liquid spray nozzles utilizing compressed air, the nozzle has structural features that the pressurized air and the liquid are maintained separately until reaching at the head of double-pipe fluid atomizing nozzle, and suction, shearing and atomizing occur instantly upon contacting at the front end of the double-pipe. In this case, the pressurized air discharged in high speed from outside pipe induces highly negative pressure around the front end portion to cause the liquid being sucked from the inner pipe and sheared. However, due to simultaneous sucking of air from outside of the system, a large portion of kinetic energy of the compressed air is wasted for accelerating the external air.
On the other hand in the atomizing nozzle of the present invention, the nozzle has the structural features that the liquid material is revolved and accelerated in the cylindrical chamber by the ejected pressurized air to be atomized partly, and the remaining portion is forwarded to the orifice under film state of accelerated revolution. For example, when a compressed air of 3 kg/cm2 pressure is employed, around 2 kg/cm2 pressure is consumed in the cylindrical chamber and the remaining pressure becomes the kinetic energy for spraying from the orifice, though the ratio varies in accordance with ratios of the area of circular opening 5 of orifice to the total cross-sectional area of through holes 3 for compressed air. As the result, the portion of energy consumed for atomizing liquid is larger than that of conventional spray nozzles.
Ratios of necessary amount of the compressed air to the amount of liquid varies widely in accordance with properties of the liquid (viscosity, surface tension, size of solid material, etc.) and average particle sizes desired. The compressed air employable is 4-7 kg/cm2 pressure, as general purpose air compressors usually have 7 kg/cm2 specifications. Air through holes of the cylindrical chamber are set to have (total) cross-sectional area allowing to pass through a predetermined amount of air under pressure difference of 1 kg/cm2 lower than the set air pressure. The orifice is set to have an opening area capable of passing a predetermined amount of air under 0.5-1.5 kg/cm2 pressure difference. A too large orifice opening area results lowered axial velocity by comparison with the whirling velocity, which causes difficulty in atomizing liquid film rings at the orifice portion. Thus, unfavorably larger particles tend to appear in outward direction, though a widened spray angle may be obtainable. From this viewpoint, the ejecting air at the opening of orifice preferably has a velocity corresponding to 0.5-1.5 kg/cm2 pressure difference. In order to attain desirous atomization with such a small amount of pressurized air, it is quite important to select properly the (total) cross-sectional area of the air through holes in the cylindrical chamber and opening area of the orifice. It is preferred that the ratio of diameter of the circular opening 5 of orifice / inside diameter of the cylindrical chamber 2 is in the range of 1 : 1.5-4.0; and the ratio of area of the circular opening 5 of orifice / total cross-sectional area of throuqh holes 3 opened tangentially to circular internal surface of cylindrical chamber is in the range of 1 : 0.2-lØ
Different from conventional liquid atomizing nozzles employing two fluids, the nozzle according to the present invention can employ an enlarged diameter liquid supplying pipe thanks to being scarcely affected on the atomizing features by pipe diameters, and the diameter of orifice can also be enlarged. Accordingly, it is possible to atomize liquid materials not only in large amount or of high viscosity but also containing coarse solid materials. Since the atomized liquid particles possess higher revolving momentum and lower axial velocity in comparison with those of conventional nozzles, the atomized liquid particles can be spread so broadly as to be beneficial for usages in spray dryers.
In order to enlarge further the spray angle, a reverse conical body lO is disposed coaxially inside of the opening 5 of the orifice 4 as shown in Fig.9, which enables a spray angle of near to that of pressure spray nozzles. Fig.10 shows the reverse conical body 10 attached to the connecting rod 11. By fixing the end of connecting rod 11 to the head of the liquid supplying pipe 1, the reverse conical body 10 can be disposed coaxially inside of the opening 5 of the orifice 4. In this case, the circular opening 5 of the orifice 4 is preferably shaped into the reverse conical shape, as shown in Fig.11. As mentioned previously, a liquid material passed into the cylindrical chamber 2 from the liquid supplying pipe 1 is dispersed, revolved and accelerated in the cylindrical chamber by virtue of the pressurized air coming into at a high speed from the through holes 3 in the direction tangential to circular internal surface of the cylindrical chamber, and is transformed to thin liquid film through centrifugal force, and transferred toward internal surface of the cylindrical chamber. In order to enhance transferring the liquid material to internal surface of the cylindrical chamber, a disc-type liquid distributor 12 having a plurality of liquid ejecting holes 13 (top view:
Fig.12; sectional view: Fig.13) placed evenly and concentrically is preferably disposed (in the cylindrical chamber) at a place between the one or more through holes 3 for passing through pressurized air in the direction tangential to the circular internal surface of the cylindrical chamber and the connecting portion of the liquid supplying pipe (cf. Fig.9). When the reverse conical body 10 is disposed in the opening 5 of the orifice 4 as shown by Fig.9, since front end of the liquid supply pipe 1 is clogged by the connecting rod 11 of the reverse conical body 10, it may be so arranged as the liquid material can be supplied to end portion of the cylindrical chamber 2 through the side hole 14 disposed near front end of the liquid supplying pipe 1, and the liquid supplied is introduced around internal surface of the cylindrical chamber 2 through the liquid ejecting hole 13 of the disc-type liquid distributor 12. Even when the reverse conical body 10 is not attached, liquid distributor 12 can be disposed effectively.
In order to provide the liquid material with rotary movement prior to be charged to bottom portion of the cylindrical chamber 2, a disc-type liquid revolving plate 15, shown by Fig.14 in top view and by Fig.15 in side view, having one or more of inclined slits 16 circumferentially for revolving liquid is disposed effectively (in the cylindrical chamber) at a place between the one or more through holes for passing through 0 pressurized air in the direction tangential to the circular internal surface of the cylindrical chamber and the connecting portion of the liquid supplying pipe. For conventional nozzles of coaxial double-pipe fluid atomizing nozzles, the larger the difference in discharge velocities between the liquid material and the swift air stream, the larger the shearing and atomizing effects. Thus, a heightened supply pressure of the liquid material for increasing the discharge velocity worsens atomizing to results in adverse effects. In the present invention, arrangement of the inclined slit 16 enables pressurized supply of the liquid and decreases greatly the amount of pressurized air, which solves the essential defect of conventional double-pipe fluid atomizing nozzles. The present nozzle can be installed for existing spray dryers in place of pressurized spray nozzles, and atomization of highly viscous liquid materials unable to be atomized so far becomes feasible.
When the present nozzle is employed for a spray dryer, the nozzle is to be inserted close to the hot air supplying portion.
In that case, since the cylindrical chamber 2 and the liquid supplying pipe 1 are covered with the external cylinder 6, overheating and charring of the liquid can be prevented effectively.
When the cylindrical chamber and the orifice is so fabricated as not to be integrated but to be separable as shown in the Figs, parts having respectively several kinds of cross-sectional area enable nozzles capable of being combined suitably for processing various liquid materials. In ordinary double-pipe fluid atomizing nozzles, preparation of scores kind of nozzles of the same series are required usually, since the amount of liquid material to be processed by one specified nozzle is narrowly restricted. In the present invention, 5 kinds of nozzle openings corresponding to orifice diameters can manage liquid materials amounting to several liter/hr - several thousands liter/hr. By combining cylindrical chambers having several kinds of (total) air through hole diameters with orifices having several kinds of opening sizes, optimum atomization features are available.
In the present invention, nozzles having optional lengths for the liquid supply pipe and for the external cylinder can be fabricated, and even extremely lengthy ones are manageable by mere increases in costs added for the increased weight of pipe materials. Even when the head portion of nozzle is inserted into high temperature regions of a spray dryer or drying-incinerator, connecting portions of the liquid supplying pipe and pressurized air supplying pipe remain outside of the inserting portion of nozzle, which enables easy releasing of connection pipes and hoses. Further, since the nozzle is overhauled easily for cleaning without using special tools, the nozzle is suitable for uses in food industries and changeover of multiple products.
[Example 1]
Waste liquors of SHOUCHU spirit contains 90% or more of water and includes grain shells of several mm and fibrous materials of several tens mm. Though those apparently solid materials as dehydrated activated sludges can be incinerated with rotary kilns, waste liquors of SHOUCHU spirit are not treated similarly because of being truly liquid materials.
However, by use of the liquid atomizing nozzle according to the present invention having the under-mentioned specification, waste liquors of SHOUCHU spirit could be atomized and sprayed in a rotary kiln for evaporating main portion of the water, and the residue was deposited on the kiln wall. The deposit was a solid material containing about 50% of water and resembled to dehydrated activated sludges, which was easily incinerated in the kiln and turned to ash. Since bulky solid materials hinder the atomization, they must be crushed for processing with a spray dryer, but they cause almost no trouble in incinerating in a kiln.
Inside diameter of liquid supplying pipe : 09.5 mm Diameter of orifice opening : 07.5 mm Amount of liquid supplied : 600L/Hr Air pressure : 3kg/cm2 Amount of pressurized air supplied : 0.6Nm3/min [Example 2]
A viscous liquid of over 20,000 cP which was unable to be atomized by use of a spray dryer with a small pressurized spray 5 nozzle was turned to dried powder by use of the liquid atomizing nozzle according to the present invention having the under-mentioned specification. The pressurized spray nozzle exhibited a spray angle of larger than 70~ for a low viscosity liquid.
Though the present atomizing nozzle without the reverse conical body exhibited about 30~ of spray angle but provided atomized liquid capable of being dried without adhesion to turn into dried powder of good quality.
Inside diameter of liquid supply pipe : 07.Omm Diameter of orifice opening : 04.Omm Amount of liquid supplied : 40L/Hr Air pressure : 3kg/cm2 Amount of pressurized air supplied : 0.2Nm3/min Average particle size : 25
Liquid atomizing nozzles having compressed air power sources are widely used in such fields of spray drying, coating works of liquid materials. The nozzle is basically composed of a liquid supplying pipe and a compressed air supplying pipe coaxially arranged outside of the liquid supplying pipe. By means of compressed air from the head of air supplying pipe blasting at a high speed in the axial direction, the liquid pushed or sucked outward from the head of liquid supplying pipe is sheared and atomized.
The amount of liquid processed by this kind of coaxial double-pipe liquid atomizing nozzles is usually from several liter/hr to dozens liter/hr, because atomizing features of the nozzles worsens when the nozzle is enlarged analogously in proportion to increased amount of liquid to be processed (increased ratio of compressed air and flattened distribution of atomized liquid particles).
Since an enlarged diameter of liquid supplying pipe worsens the atomizing features, diameters of liquid supplying pipe are set at around 0.5-3.0mm. Accordingly, liquid atomizing nozzles of this type are not suitable for atomizing liquids of so highly viscous as scores of thousands cP (centipoise) or those containing bulky solid materials. Further, atomizing nozzles of this type are too narrow in spray angles to be employed as atomizing equipments of spray dryers that they can not substitute for pressurized spray nozzles having spray angles of larger than 70 degree. For relatively low viscous (below 500 cP) liquids capable of being atomized with pressurized spray nozzles, conventional double-pipe fluid atomizing nozzles require 2-5 times more atomizing energy (kw) than that required by pressurized spray nozzles. This is the reason why large capacity double-pipe fluid atomizing nozzles are not so popular.
SUMMARY OF THE INVENTION
The present invention is directed to provide a liquid atomizing nozzle capable of atomizing liquid materials of highly viscous or containing bulky solid materials charged not only at a small feed rate but also at several thousands liter/hr rate, by which the liquid is atomized and sprayed uniformly with a predetermined spray angles.
The liquid atomizing nozzle according to the present invention comprises a liquid supplying pipe; a cylindrical chamber for whirling of air being connected at one end with the liquid supplying pipe, having an inside diameter larger than inside diameter of the liquid supplying pipe, and being provided with one or more through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber; an orifice disposed at the top of the cylindrical chamber and having a circular opening of smaller than inside diameter of the cylindrical chamber; and an external cylinder covering over the cylindrical chamber and at least a part of the liquid supplying pipe and being provided with a pressurized air supplying pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.1 is a longitudinal section of the liquid atomizing nozzle according to the present invention; Fig.2 is a longitudinal section of the liquid supplying pipe; Fig.3 is a longitudinal section of the cylindrical chamber; Fig.4 is a sectional view seen along A-A of the cylindrical chamber of Fig.3; Fig.5 is a longitudinal section of the orifice; Fig.6 is a view of the orifice of Fig.5 seen from the direction C; Fig.7 is a longitudinal section of the external cylinder; Fig.8 is a longitudinal section of a seal cap; Fig.9 is a longitudinal section of the liquid atomizing nozzle equipped with a reverse conical body and a disc-type liquid distributor; Fig.10 is a side view of the reverse conical body; Fig.11 is sectional view of the orifice used in combination with the reverse conical body; Fig.12 is a top view of the disc-type liquid distributor;
Fig.13 is sectional view along D-D of the disc-type liquid distributor of Fig.12; Fig.14 is a top view of a disc-type liquid revolving plate; Fig.15 is a side view of the disc-type liquid revolving plate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The liquid atomizing nozzle according to the present invention will be explained by reference to the attached drawings.
Reference number 1 indicates the liquid supplying pipe, and the pipe is connected with the cylindrical chamber for whirling of air 2 at one end exemplified by the left end in Fig.l. The cylindrical chamber 2 has a cylindrical shape having inside diameter larger than inside diameter of the liquid supplying pipe l, and is provided at the cylindrical portion with one or more through holes 3 for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber. As shown by Fig.4 by the cross-sectional view, a plurality of the through holes 3 for passing through pressurized air may be disposed along the same circumference (c.f. Fig.4) or in rows in axial direction of the cylindrical chamber (e.g. at A-A and B-B in Fig.3). A plurality of through holes may be arranged along the same circumfere~ce and a plurality of circumferential arrangements may be disposed in rows in the axial direction. The orifice 4 having the circular opening 5 of smaller than inside diameter of the cylindrical chamber is disposed at the head of the cylindrical chamber 2.
Further, the external cylinder 6 is so disposed as to cover the cylindrical chamber 2 and at least a part of the liquid supplying pipe 1, and the pressurized air supplying pipe 7 is connected therewith. Reference number 9 is a seal for sealing the other end of the external cylinder 6, and reference number 8 is a seal cap.
S The liquid atomizing nozzle according to the invention can be assembled easily by steps of inserting the liquid supplying pipe 1 into a connection opening disposed at the bottom of the cylindrical chamber 2; inserting into the external cylinder 6 the cylindrical chamber attached with the liquid supplying pipe;
fastening the orifice 4 to front end of the external cylinder 6 to fasten the front end of the cylindrical chamber 2; engaging the seal cap 8 having a through hole for the liquid supplying pipe 1 at the back end of the external cylinder 6; and turning thus assembled nozzle to air-tight or water-tight by means of applying appropriately sealing materials. Disassembling or exchanging such parts as the cylindrical chamber 2 and/or orifice 4 can be done easily.
Working mechanism of the liquid spray nozzle of the present invention will be explained hereunder. Liquid material supplied into the cylindrical chamber 2 through the liquid supplying pipe 1 is revolved and accelerated in the cylindrical chamber by virtue of the pressurized air coming in at a high speed from the through holes 3 in the direction tangential to circular internal surface of the cylindrical chamber. The accelerated revolving liquid material moves by means of centrifugal force toward internal surface of the cylindrical chamber, turns to thin film, moves toward the circular opening 5, and is sprayed therefrom with accompaniment of whirling air stream. In this case, fine liquid particles are accompanied by air stream ejected into the cylindrical chamber. Other liquid flows in a thin film state along the internal surface of cylindrical chamber, atomized at S the opening 5 of orifice and sprayed.
In conventional liquid spray nozzles utilizing compressed air, the nozzle has structural features that the pressurized air and the liquid are maintained separately until reaching at the head of double-pipe fluid atomizing nozzle, and suction, shearing and atomizing occur instantly upon contacting at the front end of the double-pipe. In this case, the pressurized air discharged in high speed from outside pipe induces highly negative pressure around the front end portion to cause the liquid being sucked from the inner pipe and sheared. However, due to simultaneous sucking of air from outside of the system, a large portion of kinetic energy of the compressed air is wasted for accelerating the external air.
On the other hand in the atomizing nozzle of the present invention, the nozzle has the structural features that the liquid material is revolved and accelerated in the cylindrical chamber by the ejected pressurized air to be atomized partly, and the remaining portion is forwarded to the orifice under film state of accelerated revolution. For example, when a compressed air of 3 kg/cm2 pressure is employed, around 2 kg/cm2 pressure is consumed in the cylindrical chamber and the remaining pressure becomes the kinetic energy for spraying from the orifice, though the ratio varies in accordance with ratios of the area of circular opening 5 of orifice to the total cross-sectional area of through holes 3 for compressed air. As the result, the portion of energy consumed for atomizing liquid is larger than that of conventional spray nozzles.
Ratios of necessary amount of the compressed air to the amount of liquid varies widely in accordance with properties of the liquid (viscosity, surface tension, size of solid material, etc.) and average particle sizes desired. The compressed air employable is 4-7 kg/cm2 pressure, as general purpose air compressors usually have 7 kg/cm2 specifications. Air through holes of the cylindrical chamber are set to have (total) cross-sectional area allowing to pass through a predetermined amount of air under pressure difference of 1 kg/cm2 lower than the set air pressure. The orifice is set to have an opening area capable of passing a predetermined amount of air under 0.5-1.5 kg/cm2 pressure difference. A too large orifice opening area results lowered axial velocity by comparison with the whirling velocity, which causes difficulty in atomizing liquid film rings at the orifice portion. Thus, unfavorably larger particles tend to appear in outward direction, though a widened spray angle may be obtainable. From this viewpoint, the ejecting air at the opening of orifice preferably has a velocity corresponding to 0.5-1.5 kg/cm2 pressure difference. In order to attain desirous atomization with such a small amount of pressurized air, it is quite important to select properly the (total) cross-sectional area of the air through holes in the cylindrical chamber and opening area of the orifice. It is preferred that the ratio of diameter of the circular opening 5 of orifice / inside diameter of the cylindrical chamber 2 is in the range of 1 : 1.5-4.0; and the ratio of area of the circular opening 5 of orifice / total cross-sectional area of throuqh holes 3 opened tangentially to circular internal surface of cylindrical chamber is in the range of 1 : 0.2-lØ
Different from conventional liquid atomizing nozzles employing two fluids, the nozzle according to the present invention can employ an enlarged diameter liquid supplying pipe thanks to being scarcely affected on the atomizing features by pipe diameters, and the diameter of orifice can also be enlarged. Accordingly, it is possible to atomize liquid materials not only in large amount or of high viscosity but also containing coarse solid materials. Since the atomized liquid particles possess higher revolving momentum and lower axial velocity in comparison with those of conventional nozzles, the atomized liquid particles can be spread so broadly as to be beneficial for usages in spray dryers.
In order to enlarge further the spray angle, a reverse conical body lO is disposed coaxially inside of the opening 5 of the orifice 4 as shown in Fig.9, which enables a spray angle of near to that of pressure spray nozzles. Fig.10 shows the reverse conical body 10 attached to the connecting rod 11. By fixing the end of connecting rod 11 to the head of the liquid supplying pipe 1, the reverse conical body 10 can be disposed coaxially inside of the opening 5 of the orifice 4. In this case, the circular opening 5 of the orifice 4 is preferably shaped into the reverse conical shape, as shown in Fig.11. As mentioned previously, a liquid material passed into the cylindrical chamber 2 from the liquid supplying pipe 1 is dispersed, revolved and accelerated in the cylindrical chamber by virtue of the pressurized air coming into at a high speed from the through holes 3 in the direction tangential to circular internal surface of the cylindrical chamber, and is transformed to thin liquid film through centrifugal force, and transferred toward internal surface of the cylindrical chamber. In order to enhance transferring the liquid material to internal surface of the cylindrical chamber, a disc-type liquid distributor 12 having a plurality of liquid ejecting holes 13 (top view:
Fig.12; sectional view: Fig.13) placed evenly and concentrically is preferably disposed (in the cylindrical chamber) at a place between the one or more through holes 3 for passing through pressurized air in the direction tangential to the circular internal surface of the cylindrical chamber and the connecting portion of the liquid supplying pipe (cf. Fig.9). When the reverse conical body 10 is disposed in the opening 5 of the orifice 4 as shown by Fig.9, since front end of the liquid supply pipe 1 is clogged by the connecting rod 11 of the reverse conical body 10, it may be so arranged as the liquid material can be supplied to end portion of the cylindrical chamber 2 through the side hole 14 disposed near front end of the liquid supplying pipe 1, and the liquid supplied is introduced around internal surface of the cylindrical chamber 2 through the liquid ejecting hole 13 of the disc-type liquid distributor 12. Even when the reverse conical body 10 is not attached, liquid distributor 12 can be disposed effectively.
In order to provide the liquid material with rotary movement prior to be charged to bottom portion of the cylindrical chamber 2, a disc-type liquid revolving plate 15, shown by Fig.14 in top view and by Fig.15 in side view, having one or more of inclined slits 16 circumferentially for revolving liquid is disposed effectively (in the cylindrical chamber) at a place between the one or more through holes for passing through 0 pressurized air in the direction tangential to the circular internal surface of the cylindrical chamber and the connecting portion of the liquid supplying pipe. For conventional nozzles of coaxial double-pipe fluid atomizing nozzles, the larger the difference in discharge velocities between the liquid material and the swift air stream, the larger the shearing and atomizing effects. Thus, a heightened supply pressure of the liquid material for increasing the discharge velocity worsens atomizing to results in adverse effects. In the present invention, arrangement of the inclined slit 16 enables pressurized supply of the liquid and decreases greatly the amount of pressurized air, which solves the essential defect of conventional double-pipe fluid atomizing nozzles. The present nozzle can be installed for existing spray dryers in place of pressurized spray nozzles, and atomization of highly viscous liquid materials unable to be atomized so far becomes feasible.
When the present nozzle is employed for a spray dryer, the nozzle is to be inserted close to the hot air supplying portion.
In that case, since the cylindrical chamber 2 and the liquid supplying pipe 1 are covered with the external cylinder 6, overheating and charring of the liquid can be prevented effectively.
When the cylindrical chamber and the orifice is so fabricated as not to be integrated but to be separable as shown in the Figs, parts having respectively several kinds of cross-sectional area enable nozzles capable of being combined suitably for processing various liquid materials. In ordinary double-pipe fluid atomizing nozzles, preparation of scores kind of nozzles of the same series are required usually, since the amount of liquid material to be processed by one specified nozzle is narrowly restricted. In the present invention, 5 kinds of nozzle openings corresponding to orifice diameters can manage liquid materials amounting to several liter/hr - several thousands liter/hr. By combining cylindrical chambers having several kinds of (total) air through hole diameters with orifices having several kinds of opening sizes, optimum atomization features are available.
In the present invention, nozzles having optional lengths for the liquid supply pipe and for the external cylinder can be fabricated, and even extremely lengthy ones are manageable by mere increases in costs added for the increased weight of pipe materials. Even when the head portion of nozzle is inserted into high temperature regions of a spray dryer or drying-incinerator, connecting portions of the liquid supplying pipe and pressurized air supplying pipe remain outside of the inserting portion of nozzle, which enables easy releasing of connection pipes and hoses. Further, since the nozzle is overhauled easily for cleaning without using special tools, the nozzle is suitable for uses in food industries and changeover of multiple products.
[Example 1]
Waste liquors of SHOUCHU spirit contains 90% or more of water and includes grain shells of several mm and fibrous materials of several tens mm. Though those apparently solid materials as dehydrated activated sludges can be incinerated with rotary kilns, waste liquors of SHOUCHU spirit are not treated similarly because of being truly liquid materials.
However, by use of the liquid atomizing nozzle according to the present invention having the under-mentioned specification, waste liquors of SHOUCHU spirit could be atomized and sprayed in a rotary kiln for evaporating main portion of the water, and the residue was deposited on the kiln wall. The deposit was a solid material containing about 50% of water and resembled to dehydrated activated sludges, which was easily incinerated in the kiln and turned to ash. Since bulky solid materials hinder the atomization, they must be crushed for processing with a spray dryer, but they cause almost no trouble in incinerating in a kiln.
Inside diameter of liquid supplying pipe : 09.5 mm Diameter of orifice opening : 07.5 mm Amount of liquid supplied : 600L/Hr Air pressure : 3kg/cm2 Amount of pressurized air supplied : 0.6Nm3/min [Example 2]
A viscous liquid of over 20,000 cP which was unable to be atomized by use of a spray dryer with a small pressurized spray 5 nozzle was turned to dried powder by use of the liquid atomizing nozzle according to the present invention having the under-mentioned specification. The pressurized spray nozzle exhibited a spray angle of larger than 70~ for a low viscosity liquid.
Though the present atomizing nozzle without the reverse conical body exhibited about 30~ of spray angle but provided atomized liquid capable of being dried without adhesion to turn into dried powder of good quality.
Inside diameter of liquid supply pipe : 07.Omm Diameter of orifice opening : 04.Omm Amount of liquid supplied : 40L/Hr Air pressure : 3kg/cm2 Amount of pressurized air supplied : 0.2Nm3/min Average particle size : 25
Claims (7)
What is claimed is:
1. A liquid atomizing nozzle, comprising a liquid supplying pipe; a cylindrical chamber for whirling of air being connected at one end with the liquid supplying pipe, having an inside diameter larger than inside diameter of the liquid supplying pipe, and being provided with one or more through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber; an orifice disposed at the top of the cylindrical chamber and having a circular opening of smaller than inside diameter of the cylindrical chamber; and an external cylinder covering over the cylindrical chamber and at least a part of the liquid supplying pipe and being provided with a pressurized air supplying pipe.
2. The liquid atomizing nozzle according to claim 1, wherein said through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber is disposed in plurality rows in the axial direction of the cylindrical chamber.
3. The liquid atomizing nozzle according to claim 1, wherein ratio of diameter of the circular opening of orifice to inside diameter of the cylindrical chamber is 1 : 1.5-4Ø
4. The liquid atomizing nozzle according to claim 1, wherein ratio of area of the circular opening of orifice to total cross-sectional area of the through holes for passing pressurized air tangential to circular internal surface of the cylindrical chamber being 1 : 0.2-1Ø
5. The liquid atomizing nozzle according to claim 1, wherein a reverse conical body is disposed coaxially at the circular opening of orifice.
6. The liquid atomizing nozzle according to claim 1, wherein a disc-type liquid distributor having a plurality of liquid ejecting holes placed evenly and concentrically for supplying dispersed liquid to the cylindrical chamber is disposed (in the cylindrical chamber) at a place between the one or more through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber and the connecting portion of the liquid supplying pipe.
7. The liquid atomizing nozzle according to claim 1, wherein a disc-type liquid revolving plate having one or more of inclined slits circumferentially for revolving liquid is disposed (in the cylindrical chamber) at a place between the one or more through holes for passing through pressurized air in the direction tangential to circular internal surface of the cylindrical chamber and the connecting portion of the liquid supplying pipe.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JPHEI8-316637 | 1996-11-27 | ||
| JP31663796A JPH10156230A (en) | 1996-11-27 | 1996-11-27 | Liquid spray nozzle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2221897A1 true CA2221897A1 (en) | 1998-05-27 |
Family
ID=18079259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2221897 Abandoned CA2221897A1 (en) | 1996-11-27 | 1997-11-21 | Liquid atomizing nozzle |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0845300A3 (en) |
| JP (1) | JPH10156230A (en) |
| CA (1) | CA2221897A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4869067B2 (en) * | 2003-06-27 | 2012-02-01 | レクティセル アウトモビールジステーム ゲーエムベーハー | Process for producing molded products having a sprayed polyurethane layer |
| BRPI0713490A2 (en) * | 2006-06-21 | 2012-01-24 | Clyde Bergemann Inc | variable hole for black liquor nozzle |
| CN103316793B (en) * | 2013-06-19 | 2016-07-06 | 安徽艾可蓝节能环保科技有限公司 | A kind of gas helps formula atomizer |
| CN103657913A (en) * | 2013-11-30 | 2014-03-26 | 无锡大阿福信息科技有限公司 | Sprayer nozzle structure |
| CN107126831B (en) * | 2017-06-20 | 2023-04-21 | 佛山市三水新明珠建陶工业有限公司 | Injector for SNCR denitration system |
| CN108114822B (en) * | 2018-01-25 | 2023-09-15 | 山东农业大学 | Anti-drift pneumatic atomization spray head for online regulation and control of particle size of mist drops and control method |
| US11541406B2 (en) * | 2020-03-30 | 2023-01-03 | Medmix Switzerland Ag | Spray nozzle |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3897007A (en) * | 1973-09-10 | 1975-07-29 | Joseph G Roy | Apparatus for atomizing liquid fuels for the combustion process |
| JPS5926348B2 (en) * | 1976-12-03 | 1984-06-26 | 三菱プレシジヨン株式会社 | Fluid atomization dispersion device |
| US4422900A (en) * | 1981-11-25 | 1983-12-27 | Olin Corporation | Spray drying apparatus for available chlorine-containing compounds |
-
1996
- 1996-11-27 JP JP31663796A patent/JPH10156230A/en active Pending
-
1997
- 1997-11-11 EP EP97119735A patent/EP0845300A3/en not_active Withdrawn
- 1997-11-21 CA CA 2221897 patent/CA2221897A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0845300A3 (en) | 1999-01-20 |
| EP0845300A2 (en) | 1998-06-03 |
| JPH10156230A (en) | 1998-06-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20001121 |