US3137446A

US3137446A - Multiple nozzle apparatus

Info

Publication number: US3137446A
Application number: US208434A
Authority: US
Inventors: Masuda Senichi
Original assignee: Onoda Cement Co Ltd
Current assignee: Onoda Cement Co Ltd
Priority date: 1961-08-23
Filing date: 1962-07-09
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16
Also published as: GB993277A; CH389521A

Description

J1me 1964 SENICHI MASUDA MULTIPLE NOZZLE APPARATUS 4 Sheets-Sheet 1 Filed July 9, 1962 June 16, 1964 SENICHI MASUDA MULTIPLE NOZZLE APPARATUS Filed July 9, 1962 4 Sheets-Sheet 2 l !7///IIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIII J1me 1954 SENICHI MASUDA ,4

MULTIPLE NOZZLE APPARATUS Filed July 9, 1962 4 Sheets-Sheet 3 Jun; 16, 1964 SENICHI MASUDA 3,137,446 MULTIPLE NOZZLE APPARATUS Filed July 9, 1962 4 Sheets-Sheet 4 United States Patent 3,137,446 MULTIPLE NOZZLE APPARATUS Senichi Masuda, Musashino-shi, Tokyo-to, Japan, assignor to Onoda Cement Company Limited, Onoda, Japan Filed July 9, 1962, Ser. No. 208,434 Claims priority, application Japan Aug. 23, 1961 2 Claims. (Cl. 239434) The present invention relates in general to a spray apparatus employing a so-called two-fluid nozzle which produces minute and uniform liquid particles by mixing and jetting the liquid and air, more particularly to a spray apparatus in which a plurality of such nozzles are provided in association with a common air-supply pipe and a common liquid-supply pipe so as to be operated in parallel, and in which a provision is made such that nonuniformity of spraying produced by the respective two-fluid nozzles is eliminated and thus spraying rates and sprayed particle diameters of the respective nozzles are kept completely uniform.

It has been known in the prior art that when a spray having very minute diameter particles and a uniform distribution of particles is required, the system of mixing and jetting liquid and a relatively large amount of air with respect to the amount of liquid, that is, the so-called two-fluid nozzle, is most suitable to produce this result.

The diameter of the sprayed particles obtained by means of such type of nozzle, depends upon the flowing rates of liquid and air supplied thereto, and therefore, if a predetermined diameter of liquid spray is desired to be obtained, the flowing rates of the liquid and air must be maintained at the predetermined values corresponding to the desired diameter.

In case that a large amount of spray having a minute and uniform particle diameter is required and it is intended to use the above-mentioned two fluid nozzle for this purpose, if the number of the two-fluid nozzles used is one, the pressures required for the sources of air and the liquid become extremely high because of the excessively large flowing rates of air and the liquid, thus resulting in a large necessary power for a compressor associated with the air source and for a pump associ ated with the liquid source, this proves to be uneconomical. Accordingly, in order to avoid such disadvantage, it is necessary to increase the number of'two-fluid nozzles to a proper number, and to use these nozzles in parallel so as to limit the flowing rates of air and liquid served by a single two-fluid nozzle.

In this case, for simplicity of piping, it is desirable to provide the respective nozzles in association with a common air piping and a common liquid piping. However, if such a provision is made, the spraying rates and the sprayed particle diameters of the respective nozzles, in general, become extremely unbalanced, and for some of the nozzles the spraying rate increases and the sprayed particles become coarse, while for the other nozzles the spraying rate decreases and the sprayed particles become extremely fine. In an extreme case, even it may be possible that from some of the nozzles only the liquid is jetted, while from the other nozzles only air is jetted.

This is caused by the fact that the distribution of the liquid flow over the respective nozzles becomes quite unequal, although the air flow is equally distributed over the respective nozzles. This equal air flow is no problem, because with regard to-the air flow the resistance of the jet opening at the extreme end of the nozzle occupies the greater part of the air piping circuit resistance, and these nozzle resistances are equal to each other at the respective nozzles. This is because the air would enter into the liquid piping due to the generally very low rate of the liquid flow with respect to the air flow, the liquid flowing in a layer along the inner wall of the piping,

and accordingly the liquid cannot equally enter into the branch pipes for the respective nozzles from the common liquid piping.

Therefore, according to the prior method, in the case of employing a number of nozzles so as to produce a large amount of spray having a predetermined minute and uniform particle diameter, it becomes essential to provide separate air and liquid pipings for each nozzle and to regulate the flowing rates of the liquid and air supplied to each nozzle as by means of a valve so that they may become completely equal, respectively. This, however, extremely complicates the pipings and thus strictly limits the increase in number of the nozzles from a practical and economical point of View.

The present invention provides a method which elimi nates the above-mentioned disadvantage, and equalizes the spraying rates and the sprayed particle diameters for the respective nozzles to each other as well as to the values for a single nozzle used under the same spraying condition by completely equalizing the flowing rate of the liquid distributed to the respective nozzles even in the case of providing a plurality of nozzles in association with a common air piping and a common liquid piping, and thereby is able to easily produce a completely uniform and minute spray having a predetermined flowing rate and a predetermined particle diameter by providing a plurality of corresponding nozzles in association with a common air piping and a common liquid piping and operating them in parallel under the corresponding spray-1 ing condition.

The novel method according to the present invention is characterized by the fact that upon providing a plu rality of two-fluid nozzles in association with a common air piping and a common liquid piping, a fluid resistor which has sufficiently high resistance with respect to the fluid resistance of the common and branch liquid piping circuit is inserted for each nozzle at any place along the branch liquid piping circuit leading from the common liquid piping to the respective nozzles. This fluid resistor may be realized either by an orifice, iris, capillary tube, etc. having a fixed resistance value. In

general, however, those having a fixed resistance value,-

especially an orifice, are preferable. In addition, the re-; sistance value is preferably at least five times as high as the total fluid resistance of the common and branch liquid piping circuits (from a main valve to each nozzle),

and normally it is suflicient if the factor is taken as 10 to 20 times. The above-referred fluid resistor for each nozzle may be selected to have different resistance values for the respective nozzles so as to strictly equalize the liquid flowing rates through the respective nozzles by equalizing the total fluid resistance from a liquid source or a main valve in a common liquid piping to each noz-- zle. However, since the above-referred liquid resistance itself generally occupies the greater part of the total liquid piping resistance, even if the same resistance value is taken by the respective nozzles, no significant difference occurs between the liquid flowing rates for the respective nozzles, and therefore, this is more preferable. Furthermore, though the above-referred liquid resistor may be located at any place along the above-mentioned branch liquid piping circuit, it is most preferable to provide thisin association with the nozzle itself. In addition, although the above-referred liquid resistor may be integrally formed as a part of either the nozzle itself or the abovementioned branch liquid piping circuit, it is more preferable to use such structure that only the fluid resistor is formed separately and fixedly inserted into the nozzle itself or into the above-mentioned branch piping circuitin any suitable manner, in order that the fluid resistor may be exchangable as a provision for wearing. Moreover, as the above-referred fluid resistor would be in 3 general, heavily worn, it is preferable to use hard materials therefore, and the resistor will become more effective when subjected to Kanizen plating.

The fluid resistor specially provided in the abovementioned branch liquid piping circuit, which characterizes the present invention, gives a high fluid resistance to the circuits leading from the liquid source or the main valve of the common liquid piping to the respective nozzles, and also occupies most part of the total resistance along the above-referred circuits, so that most part of the pressure drop between the liquid source or the common liquid piping and the respective nozzles (this drop essentially increases due to the insertion of the above resistor) becomes concentrated and appears across the above-referred resistor, and accordingly the unbalanced distribution of the liquid flowing rate over the respective nozzles due to the fact that air would flow backward to the upper stream beyond the above liquid resistor and that the liquid would flow in a layer along the inner wall surface within the common piping, may be completely prevented. Furthermore, since the total liquid resistances between the respective nozzles and the liquid source or the main valve of the common liquid piping are equalized regardless of the diflerence in liquid resistances for the midway piping circuits by means of the insertion of the above-referred liquid resistor, the distribution of the liquid flowing rates over the respective nozzles is made completely uniform. On the other hand, since the air flowing rates are equal to each other for the respective nozzles as described previously, the sprayed particle diameters as well as the spraying rates become quite equal to each other for the respective nozzles, and thus we can obtain a spray having perfectly uniform particle diameters as a whole. In this case, the flowing rates of air and the liquid supplied to each nozzle is exactly equal to those in the case of employing a single nozzle with the above-referred liquid resistor inserted into the liquid piping, and therefore it is a matter of course that the spray through each nozzle is equal in its flowing rate and particle diameter to that in the latter case, so long as the total resistance along the liquid piping from the liquid source of the main valve to the nozzle is negligibly small with respect to the resistance of the above-referred liquid resistor. This means that upon practicing the present invention, the spraying rate and the sprayed particle diameter corresponding to a single nozzle depend only upon the pressure (or flowing rate) of the liquid and air within the common pipings in the lower stream beyond the main valve, that if the above relation had been examined previously by means of a single nozzle with the above-referred liquid inserted into its liquid piping, tthe pressures of air and the liquid (alternatively the flowing rates of both for a single nozzle) required to obtain a predetermined particle diameter could be determined, and that by increasing the number of nozzles to be provided in association with the common pipings, the spraying rate can be increased to any extent at will without changing the sprayed particle diameter. This proves to be a distinctive advantage of the present invention.

These and other features and advantages of the present invention will become more apparent from a perusal of the following specification taken in connection with the accompanying drawings, in which:

FIG. 1 is a cross sectional view of a nozzle and common pipings according to. one preferred embodiment of the present invention in which an exchangeable orifice is fixedly inserted at a liquid inlet of the nozzle,

FIG. 2 is a perspective view of the same,

FIGS. 3-1 and 32 are a front view and a sectional view along a section line A-B of FIG. 3-1, respectively, showing a structure of an extreme end portion of a nozzle which is adapted for practicing the present invention,

FIG. 4 is a cross sectional view of another embodiment which differs from the embodiment in FIG. 1 only in the manner of arranging nozzles,

FIG. 5 is a perspective view of the same,

FIG. 6 is a cross sectional view of a nozzle according to still another embodiment of the present invention in which an orifice is formed integrally with the nozzle body at a liquid inlet of the nozzle,

FIG. 7 is a cross sectional view of a nozzle and a branch piping circuit according to another embodiment of the present invention in which an exchangeable orifice is fixedly inserted in the midway of the branch liquid piping circuit leading to the nozzle,

FIG. 8 is a cross sectional view of a dust accumulation and solidification preventing type of nozzle and its common pipings, which is especially suitable in the case of embodying the present invention for spraying within a gas atmosphere containing dust,

FIG. 9 is a perspective view of the same,

FIG. 10 is a cross sectional view of another embodiment which differs from that in FIG. 8 only in the manner of arranging nozzles, and

FIG. 11 is a perspective view of the same.

Referring now to FIG. 1 of the drawings, it illustrates the manner of embodying the present invention by forming the fluid resistor which characterize the invention as an exchangeable orifice, and fixedly inserting the same at the liquid inlet of the two-fluid nozzle so as to associate it with a common air piping and a common liquid piping. FIG. 2 is an illustration of a nozzle set in which the above-mentioned two-fluid nozzles are associated with the common pipings in such manner. In these figures, there is shown a common air piping at 1, its main valve at 2, an air pressure gauge at 3, a common liquid piping at 4, its main valve at 5, a liquid pressure gauge at 6, and a nozzle body at 7. At a liquid inlet 8 of the nozzle body, is fixedly mounted an exchangeable orifice 9 by means of a shoulder 10 and an outwardly threaded pipe 11. A packing 12 prevents the liquid from leaking out. At the extreme end of the nozzle body is mounted an exchangeable head 14 having a jet opening 13. The reason of making this part exchangeable, is because the jet opening would heavily wear, and accordingly this portion is preferably, as in the case of the orifice, made of wear-resistive materials, or subjected to Kanizen plating. The respective nozzles provided with an orifice 9 having the same high resistance value in the above-mentioned manner, are mounted on to the common air piping 1 by means of threads 15, and also mounted on to the common liquid piping 4 by means of a union 16, in a coupled relation with the respective pipings. Air is supplied from an air source, through the main valve 2, and common piping 1 to a mixing chamber 17 within the nozzle 7, while the liquid is supplied from a liquid source, through the main valve 5, common piping 4, and orifice 9 to the same chamber, and after mixed in the chamber they are jetted out from the jet opening 13. If the shape of the jet opening is circular, a conical shape of spray is obtained, while if it is rectangular, a sector shape of spray is obtained. Especially for the purpose of obtaining the latter shape of spray, a satisfactory result may be obtained by forming the extreme end 18 of the head in a semi-sphere as shown in FIGS. 31 and 3-2, and cutting out a groove PQ in parallel to surface AB as shown in the figures. The diameter of the opening 19 in the orifice 9 must be selected in such manner that the resistance due to the orifice 9 may occupy a most part of the total fluid resistance along the liquid piping circuit from the main valve 5 to the mixing chamber in each nozzle. Owing to such provision, all the liquid pressures just in front of the orifices in the respective nozzles become equal to each other as well as to the indicated value of the pressure gauge 6, and thereby the liquid flowing rates to the respective nozzles are equalized as in the case of the air flowing rates;

The flowing rates of the liquid and air supplied to the respective nozzles may be regulated by means of the valves'5 and 2, respectively, and thereby the sprayed particle diameter, spraying rate and entire shape of the spray may be varied. In order to obtain a spray having predetermined particle diameter, spraying rate and shape, it is necessary to maintain the flowing rates of the liquid and air supplied to the respective nozzles at predetermined values. For this purpose, flowing rate meters may be inserted in the common pipings for the liquid and air respectively to measure and regulate both flowing rates. Alternatively, however, this may be achieved by measuring the respective pressures by means of the pressure gauges 6 and 3 and by maintaining the pressure at predetermined values corresponding to the above-referred flowing rates, and this is simpler than the first-mentioned method.

Now illustrating one spray produced by the nozzle set according to the present invention, when the head of the type shown in FIGS. 3-1 and 3-2 having a rectangular jet opening of 1 mm. in Width and mm. in length is used, and the inner diameter of the mixing chamber 17 and branch liquid pipe 11 is mm., that of the common air piping 1 is 1 inch, and that of the common liquid piping 4 is /2 inch, the diameter of the opening 19 in the orifice 9 is required to be less than about 2 mm.; and if this diameter is taken at 2 mm., when the indicated air pressure by means of the pressure gauge 3 is 6 kg./cm. and the indicated liquid pressure by means of the pressure gauge 6 is 7 kg./cm. assuming that the liquid is water, the flowing rates of air and water become 12 Nm. /h. and 0.1 mfi/h. per unit nozzle, respectively, and thereby a spray having an average diameter of 85 is obtained.

FIG. 4 shows another embodiment of the invention, in which two-fluid nozzles having an exchangeable orifice fixedly inserted into the nozzle itself as shown in FIG. 1 are mounted in pairs on both sides of the common air and liquid pipings, and which has the same structure as the embodiment in FIG. 1 except that the coupling portion between the nozzle and the air piping consists of a union. FIG. 5 shows a nozzle set employing the arrangement in FIG. 4. When the number of nozzles to be used is great, the arrangement as shown in FIGS. 4 and 5 is especially favorable for embodying the present invention.

FIG. 6 shows another embodiment of the present invention, in which the fluid resistor characterizing the present invention is still realized by an orifice, but this is formed integrally with the nozzle body by simply machining a. part of the same rather than formed as an exchangeable means, in the figure the common air and liquid pipings being omitted and only the branch pipes and 21 being shown. At a point 8 near to the liquid inlet for the nozzle, is formed an orifice 9 integrally with the nozzle. Other reference numerals are the same as in FIG. 1.

FIG. 7 shows one example in which the present invention is embodied by providing the fluid resistor characterizing the present invention in the midway of the branch piping leading from the common liquid piping to the nozzle 7, rather than providing the same near to the liquid inlet, in this example an exchangeable orifice being used as the fluid resistor. In this figure, the common air and liquid pipings are omitted, and only the branch pipes leading therefrom to the nozzle are shown. In the midway of the branch liquid piping circuit 20 is inserted an exchangeable orifice, which is fixed in position by means of a union 16. The liquid piping between the union 16 and the liquid inlet 8 for the nozzle preferably is small in diameter so as not to introduce air therein, because the flowing rate of the liquid into the mixing chamber 17 would then cause no substantial variation. The head 14 in this figure is shown as having a circular jet opening 13. Other reference numerals are the same as in FIG. 1.

The method of employing a plurality of two-fluid nozzles in parallel according to the present invention is especially suitable for producing a fine spray having predetermined uniform particle diameters in a large amount,

and therefore it is extremely elfective in instantaneous spray vaporization of a large amount of liquid. Accordingly, uponemploying the present method for cooling or humidity controlling a gas, it is possible to achieve perfect vaporization without causing a disadvantage such as wall wetting even with a very small volume of a drying column, cooling column or humidity controlling chamber. When the present invention is applied for such purpose, preferably the sprays 'from the respective nozzles should well extend within and mix with the surrounding gas as much as possible, without colliding with each other. In such case, the arrangement of the nozzles is conveniently made in the form as shown in FIG. 5. Furthermore, a satisfactory result could be obtained by employing the heads as shown in FIGS. 3-1 and 3-2 to make the spray from each nozzle sector shaped, and by tilting the direction of the grooves serving as jet openings as shown in FIG. 5 so that the sprays may not collide with each other and may be uni-- formly dispersed in the gas. Alternatively, the nozzles on the respective sides may be arranged in an interlaced relation rather than tilting the direction of the grooves. When the arrangement in FIG. 5 is employed, the reparation between the nozzles may be about 10-50 cm. in vertical distance and about 20-100 cm. in horizontal distance. However, normally about 20 cm. of vertical distance and about 30 cm. of horizontal distance are a sutiicient reparation. I

In case that the spraying method of the present invention is employed for the purpose of humidity-controlling or cooling a gas containing dusts as in the case of humidity-controlling an input gas of an electric dust collector among the above-referred applications, if the nozzles as shown in FIGS. 1 to 5 are used, generally a vortex is generated in the lower stream of the spray due to the nozzle set, and thereby a part of the sprayed particles flow backward, collide with the nozzles or the common pipings and thus wet them with the result that the dusts accumulate and solidify thereupon and thickly cover the entire nozzle set until the spraying is prevented. In addition, this dust cover is normally so hard that it cannot be torn off by means of hammering. In such case, it is advantageous to project the extreme end of the nozzle by elongating the nozzle body as shown in FIG. 8. In this case, the distance AB in the figure is required to be at least 10 em, but normally a distance of 20-30 cm. is satisfactory. FIG. 9 illustrates a nozzle set in which the present invention is applied to the extreme end projecting type of two-fluid nozzle in FIG. 8. The reference numerals and functions of the respective items in FIGS. 8 and 9 are quite the same as those in FIGS. 1 and 2. When the number of nozzles to be used are great, in this case also the arrangement in FIG. 4 is advantageously employed. Such an arrangement is shown in FIG. 10. In this figure, a method is illustrated in which the extreme end portion of the nozzle is projected by inserting a pipe 22 between the nozzle body 7 and the head 14. FIG. 11 shows one example of nozzle set according to the arrangement in FIG. 10. The reference numerals and functions of other items are quite the same as those in FIGS. 4 and 5. When these extreme and projecting type of nozzles are used within a gas containing dusts, only a slight deposit of dusts is caused at the extreme end portion of the nozzle, and the accumulation and solidification of dusts upon other portions is eliminated. Furthermore, as the deposited dusts upon the extreme end portion may be easily torn off and may fall by means of hammering, if a step of either intermittently or continuously hammering by hand or machine is incorporated, a large amount of spraying into any kind of gas containing dusts is enabled by means of the extreme end projecting type of nozzle set as illustrated in FIGS. 9 and 11.

In each of the above-described embodiments of the present invention, as an example of a two-fluid nozzle, a two-fluid nozzle of the type such that a mixing chamber is provided within the nozzle, and air and liquid are jetted out of a jet opening at the extreme end after being mixed in this chamber, was illustrated; and the embodiments of the present invention were all described on the basis of this example. This type of two-fluid nozzle is especially suitable for producing a uniform and minute spray, and in order to achieve the above-referred purpose of instantaneous spray vaporization for cooling and humidity-controlling a gas, it is often sufl'icient to make the flowing rate in volume (converted value at a standard condition) of air 100200 times as high as that of Water. However, the present invention is applicable to any twofluid nozzles other than the inner mixing type, and it is a matter of course that the scope of the present invention covers every type of two-fluids nozzles.

What I claim is:

1. An apparatus for spraying minute diameter particles of uniform distribution from a plurality of two-fluid nozzles comprising: A common gas piping; a common liquid piping; a first series of three-branched pipes, each pipe having one branch connected to said gas piping, one branch connected to said liquid piping and one branch having a nozzle at its end thereof, said series of threebranched pipes providing nozzles in parallel; a second series of three-branched pipes connected to said common gas piping and said common liquid piping in the same manner as said first series of three-branched pipes and provided directly opposite said common gas piping and said liquid piping from said first series of three-branched pipes; and a fluid resistor in the liquid branch of each three-branched pipe, having sufiiciently greater resistance than the total remaining resistance of the entire liquid flow path in order to equalize the liquid flow rate into each said nozzle; said one branch having a nozzle at its end, further having an extension thereon upstream from said nozzle to thereby provide an exit branch having an extended length.

2. A device in accordance with claim 1 wherein said liquid branch of each of said three-branched pipes is threadedly engaged into a socket at the junction of said other two branches; and said fluid resistor comprises an exchangeable orifice plate seated in said socket.

References Cited in the file of this patent UNITED STATES PATENTS 590,128 Browning Sept. 14, 1897 1,199,149 Best Sept. 26, 1916 1,273,976 Worley July 30, 1918 2,284,443 Paradise May 26, 1942 2,317,173 Bleakley Apr. 20, 1943 2,389,702 Ullmer Nov. 27, 1945 2,479,403 Powers Aug. 16, 1949 2,622,610 Rowe et al. Dec. 23, 1952 3,013,703 Hunt Dec. 19, 1961 3,019,993 Hoover Feb. 6, 1962 FOREIGN PATENTS 1,070,872 Germany Dec. 10, 1959

Claims

1. AN APPARATUS FOR SPRAYING MINUTE DIAMETER PARTICLES OF UNIFORM DISTRIBUTION FROM A PLURALITY OF TWO-FLUID NOZZLES COMPRISING: A COMMON GAS PIPING; A COMMON LIQUID PIPING; A FIRST SERIES OF THREE-BRANCHED PIPES, EACH PIPE HAVING ONE BRANCH CONNECTED TO SAID GAS PIPING, ONE BRANCH CONNECTED TO SAID LIQUID PIPING AND ONE BRANCH HAVING A NOZZLE AT ITS END THEREOF, SAID SERIES OF THREEBRANCHED PIPES PROVIDING NOZZLES IN PARALLEL; A SECOND SERIES OF THREE-BRANCHED PIPES CONNECTED TO SAID COMMON GAS PIPING AND SAID COMMON LIQUID PIPING IN THE SAME MANNER AS SAID FIRST SERIES OF THREE-BRANCHED PIPES AND PROVIDED DIRECTLY OPPOSITE SAID COMMON GAS PIPING AND SAID LIQUID PIPING FROM SAID FIRST SERIES OF THREE-BRANCHED PIPES; AND A FLUID RESISTOR IN THE LIQUID BRANCH OF EACH THREE-BRANCHED PIPE, HAVING SUFFICIENTLY GREATER RESISTANCE THAN THE TOTAL REMAINING RESISTANCE OF THE ENTIRE LIQUID FLOW PATH IN ORDER TO EQUALIZE THE LIQUID FLOW RATE INTO EACH SAID NOZZLE; SAID ONE BRANCH HAVING A NOZZLE AT ITS END, FURTHER HAVING AN EXTENSION THEREON UPSTREAM FROM SAID NOZZLE TO THEREBY PROVIDE AN EXIT BRANCH HAVING AN EXTENDED LENGTH.