JP4575017B2 - Solid-gas mixing ejector and jet mill - Google Patents

Description

  The present invention relates to a solid-gas mixing ejector used for jetting a powdery body together with a high-pressure gas at high speed, and a jet mill using the ejector.

  The solid-gas mixing ejector is used to cause a high-pressure working gas ejected from a drive nozzle to pulverize a powdery body and eject it at high speed. For example, in the jet mill described in Patent Document 1, it is used to inject and supply a powdery material as a pulverizing material together with a high-pressure gas into a crushing chamber in which a high-speed gas (gas) swirl flow is formed. In addition, it is often used in situations where powder and gas are jetted at high speed in a mixed state.

  This solid-gas mixing ejector is configured using an unequal-diameter conduit having a constricted portion in the middle of a flow path. This unequal-diameter guide pipe has an inlet opening in front of the injection nozzle of a drive nozzle that injects high-pressure working gas, and the flow rate change caused by narrowing and widening the flow path of the high-pressure working gas introduced into this inlet The powdery substance introduced to the upstream side of the suction port is guided to the unequal-diameter guide pipe together with the working gas, and is ejected from the discharge port at a high speed.

  FIG. 5 shows a configuration example of a conventional solid-gas mixed ejector disclosed in Patent Document 1 and the like. In the same figure, (a) is a combined state of the solid-gas mixing ejector 10 ′ and the drive nozzle 20, and (b) is a sectional view showing the unequal-diameter flow guide pipe 11 ′ that forms the main part of the ejector 10 ′.

  As shown in the figure, the conventional solid-gas mixing ejector has three intake sections Z1, Z2, and Z3 on the intake side, the intermediate side, and the exhaust side between the suction port 12 and the discharge port 13. It is comprised using the equal diameter conduit tube 11 '.

  The intake side section Z1 (corresponding to the negative pressure generating portion of Patent Document 1) is formed with an expanded shape (horn shape) in which the flow path diameter gradually increases toward the upstream suction port 12. In the intake side section Z1, the high-speed working gas (gas) injected from the drive nozzle 20 and introduced into the intake port is accelerated by the narrowing of the flow path from the diameters D1 to D2. Due to the negative pressure generated by the acceleration flow, the powdery substance introduced to the suction port 12 side can be entrained in the working gas and guided into the ejector 10 '. That is, the intake side section Z1 forms a negative pressure generating portion that sucks the powdery body.

  An intermediate section Z2 (corresponding to the throat portion of Patent Document 1) is connected to the downstream end of the intake side section Z1, that is, the flow path constriction end. The intermediate section Z2 is formed by an equal-diameter channel portion in which the minimum channel diameter D2 of the intake side section Z1 continues for a predetermined length (h). The working gas and the powdery substance introduced into the intake side section Z1 are mixed and promoted while passing through the intermediate section Z2.

  An exhaust side section Z3 is connected to the downstream end of the intermediate section Z2. The exhaust side section Z3 is formed in an expanded shape (horn shape) in which the flow path diameter gradually increases toward the downstream discharge port 13. The solid-gas mixture whose mixing has been promoted in the intermediate section Z2 is guided to the discharge port while being decompressed in the exhaust side section Z3, and is ejected and discharged.

Japanese Patent No. 3335312

  In the conventional technique described above, an intermediate section Z2 in which the minimum flow path diameter D2 of the intake side section Z1 is continuous with an equal diameter is interposed at the downstream end of the intake side section Z1. This intermediate section Z2 is supposed to contribute to the promotion of mixing of the working gas and the powder. Therefore, if the objective is to obtain a good solid-gas mixing state, the intervention of the intermediate section Z2 may be effective.

  However, when paying attention to spraying the powdery material as a pulverizer into the pulverization chamber as fast as possible, such as a jet mill, the intermediate section Z2 has a continuous narrowed minimum flow path diameter D2, It has been found that the flow resistance for decelerating the working fluid (working gas), which is a carrier for transporting the powdery body, is increased, which causes a decrease in the injection speed of the powdery body transported by the working fluid.

  That is, the above-described conventional solid-gas mixing ejector 10 ′ is suitable for applications mainly aimed at increasing the solid-gas mixing state, but increases the injection speed of the powdery material conveyed by the working gas. It has been found that there is a problem that the kinetic energy of the working gas is not efficiently used for accelerating the powdery material.

  The present invention has been made in view of the technical background as described above, and an object of the present invention is to provide a solid-gas mixing ejector in which a powdery body is entrained in a high-pressure working gas ejected from a drive nozzle and ejected at a high speed. An object of the present invention is to provide a solid-gas mixing ejector that efficiently uses kinetic energy for the acceleration drive of the powdery body, thereby enabling the powdery body to be ejected at a high speed. Another object of the present invention is to provide a jet mill in which the crushing efficiency is improved by increasing the injection speed of the powdery material that is a pulverizer.

The present invention provides the following means (1) as a solving means in the solid-gas mixing ejector.
(1) A suction port is opened in front of an ejection port of a drive nozzle that ejects high-pressure working gas, and the high-pressure working gas introduced into the suction port is discharged while causing flow rate changes due to narrowing and widening of the flow path. A non-equal-diameter conduit that is guided to and discharged by discharge to the unequal-diameter conduit along with the working gas. In the solid-gas mixing ejector
The non-equal-diameter guide pipe is connected to the intake side section where the flow path diameter gradually increases toward the upstream suction port, and to the downstream end of the intake side section, and the flow path diameter from the downstream end toward the discharge port. Is formed coaxially with the exhaust side section that gradually expands,
Each of the intake side section and the exhaust side section has an expanded shape in which the flow path diameter gradually increases over the entire length from the boundary where both sections contact to the intake port and the exhaust port, and the flow length of the exhaust side section relative to the total flow path length. The solid-gas mixing ejector characterized by the fact that the ratio is 80% or more.

It is preferable or desirable that the above means (1) further includes the following means.
(2) In the means of (1), the flow path length of the suction side section is the same as the diameter of the suction port or at least 0.8 times or more and less than twice the diameter of the suction port. Mixed ejector.

  (3) The solid-gas mixing ejector according to (1) or (2), wherein the suction port diameter is 1.5 to 3 times the flow path diameter at the boundary.

  (4) In any one of the above-mentioned means (1) to (3), the flow path diameter of the intake side section changes along an arc centered on a line passing through the boundary perpendicular to the flow path axis. Solid-gas mixing ejector characterized by

  (5) In any one of the above means (1) to (4), the flow path diameter of the exhaust side section changes along an arc centered on a line passing through the boundary perpendicular to the flow path axis. Solid-gas mixing ejector characterized by

  (6) In any one of the above means (1) to (5), the flow path diameter of the exhaust side section and the flow path diameter of the intake side section are each centered on a line passing through the boundary perpendicular to the flow path axis. The radius of curvature of the arc that defines the flow path diameter change of the exhaust side section is set to 25 to 50 times the radius of curvature of the arc that defines the flow path diameter change of the intake side section. Solid-gas mixing ejector characterized by that.

  (7) In any one of the above means (1) to (6), the cross section of the suction port and the cross section perpendicular to the axis of the discharge port have substantially the same diameter, .

  (8) The solid-gas mixing ejector according to any one of the above (1) to (7), wherein the suction port is expanded to the outer diameter of the unequal-diameter guide pipe.

Further, the present invention provides the following means (9) as means for solving the problem in the jet mill: (9) In any one of the above means (1) to (9), a high pressure is introduced into the circular or annular grinding chamber. In the jet mill in which gas is injected to form a high-speed gas swirl flow and finely pulverized and crushed by injecting and supplying a powdery material as a pulverizer together with high-pressure gas into the pulverization chamber, (8) A jet mill characterized in that the powdery body is jetted and supplied into the grinding chamber using the solid-gas mixing ejector according to any one of (8).

  In a solid-gas mixing ejector in which a powdery body is entrained in a high-pressure working gas ejected from a drive nozzle and jetted at high speed, the kinetic energy of the working fluid is efficiently used for acceleration driving of the powdery body, thereby It is possible to provide a solid-gas mixing ejector that can jet a body at high speed. Moreover, the jet mill which improved the crushing efficiency can be provided by raising the injection speed of the powdery body which is a crushing material.

  FIG. 1 shows an embodiment of a solid-gas mixing ejector according to the present invention. In the same figure, (a) is a combined state of the solid-gas mixing ejector 10 and the drive nozzle 20, and (b) is a sectional view showing the non-equal-diameter conduit 11 constituting the main part of the ejector 10.

  A solid-gas mixing ejector 10 shown in the figure is for ejecting a solid powder at high speed with expectation of operation, and an unequal-diameter conduit having a channel constriction between an inlet 12 and an outlet 13. 11 is used. The unequal-diameter conduit 11 forms an unequal-diameter channel that has a circular cross-section of a straight-line passage in the coaxial direction and narrows and expands around the axis.

  The unequal-diameter guide pipe 11 is installed so that the suction port 12 is opened in front of the injection port of the drive nozzle 20 that injects the high-pressure working gas, as shown in FIG. The drive nozzle 20 and the unequal-diameter guide pipe 11 are arranged on a straight line. A powder supply space 22 is formed between the ejection port of the drive nozzle 20 and the unequal-diameter guide pipe 11, that is, upstream of the suction port 12.

  The high-pressure working gas introduced from the drive nozzle 20 to the suction port 12 is guided to the discharge port 13 and ejected and discharged while causing a change in flow rate due to narrowing and widening of the flow path. Accordingly, the powdery substance introduced to the upstream side of the suction port 12 is guided to the unequal-diameter guide pipe 11 together with the working gas and is jetted from the discharge port 13 at a high speed. .

  The unequal-diameter guide pipe 11 is connected to an intake side section S1 whose flow path diameter gradually increases toward the upstream inlet 12 and a downstream end of the intake side section S1, as shown in FIG. In addition, an exhaust side section S2 whose flow path diameter gradually increases from the downstream end toward the discharge port 13 is formed coaxially. In the illustrated embodiment, the discharge port 13 is opened obliquely, but is formed to have a substantially equal diameter (D1≈D3) with the suction port 12 in a cross section orthogonal to the axis.

  Each of the intake side section S1 and the exhaust side section S2 has an expanded shape in which the flow path diameter gradually increases over the entire length from the boundary where both sections S1 and S2 are in contact to the intake port 12 and the exhaust port 13, and the intake side section S1 The flow path length j of the exhaust side section S2 is configured to be sufficiently longer than the flow path length (h). Specifically, the ratio of the flow path length (j) of the exhaust side section S2 to the total flow path length (h + j) is 80% or more (j / (h + j) ≧ 0.8).

  Further, in the illustrated embodiment, the flow path length (h) of the intake side section S1 is formed to be approximately the same size as the diameter D1 of the intake port. The suction port diameter D1 is formed to be about twice the flow path diameter (D2) at the boundary.

  The flow path diameter of the intake side section S1 is formed so as to change along an arc centered on a line L12 passing through the boundary perpendicular to the flow path axis. Further, the flow path diameter of the exhaust side section S2 is formed so as to change along an arc centered on a line L12 passing through the boundary perpendicular to the flow path axis.

  That is, both the flow path diameter of the intake side section S1 and the flow path diameter of the exhaust side section S2 are formed so as to change along an arc centered on a line L12 passing through the boundary perpendicular to the flow path axis. The former forms a flow path that narrows from the suction port 12 toward the boundary, and the latter forms a horn-shaped flow path that gradually expands from the boundary toward the discharge port 13.

  The radius of curvature R2 of the arc that defines the flow path diameter change of the exhaust side section S2 is within the range in which the horn-shaped expanded shape is effectively formed, and the radius of curvature R1 of the arc that defines the flow path diameter change of the intake side section S1. It is set sufficiently larger than. Specifically, a range of R2 / R1 = 25 to 50 times is appropriate. The suction port 12 and the discharge port 13 are formed with substantially the same diameter.

  In the solid-gas mixing ejector 10 of the above-described embodiment, first, the high-speed working gas (gas) injected from the drive nozzle 20 is accelerated by the narrowing of the flow path in the intake side section S1, and the negative pressure generated by this acceleration flow As a result, the powdery substance introduced to the suction port 12 side is caused to flow through the unequal-diameter guide pipe 11 in such a manner that it is entrained in the working gas, and the flow channel constriction in the suction side section S1 is passed through the working gas. Passes through with acceleration.

  The gas-solid mixture gas accelerated in the intake side section S1 is guided to the exhaust side section S2 connected to the downstream end of the intake side section S1, where it is guided to the discharge port while being gradually reduced in pressure and discharged. The

  It should be noted here that the mixture of the working gas and the powdery material accelerated in the flow path constriction portion of the intake side section S1 does not pass through the intermediate section where the diameter-reduced flow path is continuous, and does not pass through the exhaust side section S2. In this way, the flow resistance that reduces the kinetic energy of the mixed gas can be greatly reduced, and the powdery body can be jetted at high speed.

  In this case, since the intermediate section (throat portion) is not interposed, there is a concern that the mixing ratio of the working gas and the powder is reduced. However, by replacing the length of the intermediate section with the length of the exhaust side section S2. That is, it has been found that by increasing the length (j) of the exhaust side section S2 by an amount corresponding to the intermediate section, solid-gas mixing is considerably promoted in the exhaust side section S2.

  As described above, the solid-gas mixing ejector 10 according to the present invention has a two-section configuration including only the intake side section S1 and the exhaust side section S2 without interposing an intermediate section. The kinetic energy of the working gas can be efficiently applied to the acceleration drive of the powdery body, whereby the powdery body can be ejected at a high speed.

  In the solid-gas mixing ejector 10 according to the present invention, the flow path length h of the intake side section S1 is preferably the same as the diameter D1 of the intake port or at least 0.8 times or more and less than 2 times the diameter D1. If it is less than 0.8 times, the resistance acting between the working gas and the inner wall surface of the suction port 12 increases, and if it is twice or more, the efficiency when the powdery body is entrained in the working gas and accelerated is lowered.

  In addition, the ratio (D1 / D2) of the suction port diameter D1 and the flow path diameter at the boundary is preferably 1.5 times or more and 3 times or less. If the ratio is less than 1.5 times, the efficiency of generating negative pressure is reduced due to insufficient channel constriction. On the other hand, if the ratio exceeds three times, the channel at the constriction becomes too narrow and the channel resistance increases.

  As described above, the flow path diameter of the intake-side section S1 is changed along an arc centered on the line L12 passing through the boundary perpendicular to the flow path axis. The acceleration of the gas can be made smooth. Similarly, as described above, the flow path diameter of the exhaust side section S2 is also changed along an arc centered on the line L12 passing through the boundary perpendicular to the flow path axis. This is effective for causing the solid-gas mixture accelerated in the S1 section to be gradually decompressed and sprayed at high speed while maintaining its kinetic energy.

  For the same reason, the radius of curvature R2 of the arc that defines the change in flow path diameter of the exhaust side section S2 is preferably in the range of 25 to 50 times the radius of curvature R1 of the arc that defines the change of flow path diameter of the intake side section S1. .

FIG. 2 shows another embodiment of the solid-gas mixing ejector according to the present invention. In the same figure, (a) is a combined state of the solid-gas mixing ejector 10 and the drive nozzle 20, and (b) is a sectional view showing the non-equal-diameter conduit 11 constituting the main part of the ejector 10.
Focusing on the difference from the embodiment shown in FIG. 1, in the example body shown in FIG. 2, the opening of the inlet 12 is expanded to the outer diameter D4 of the flow guide tube 11 (D1≈D4). That is, although the edge surface of the flow guide tube 11 has an edge shape, it is possible to increase the suction efficiency of the powdery body.

  FIG. 3 shows a cross-sectional view of a main part of a jet mill 30 using a solid-gas mixing ejector according to the present invention. FIG. 4 shows the AA partial cross section of FIG. Parts common to FIGS. 1 and 2 are denoted by common reference numerals.

  The jet mill 30 shown in FIGS. 3 and 4 injects a high-pressure gas into a circular or annular pulverization chamber 32 to form a high-speed gas swirl flow, and a pulverized powder material in the pulverization chamber 32. The above-described solid-gas mixing ejector 10 is used in a portion where the powdered material is injected and supplied into the pulverizing chamber 32 by being supplied and supplied together with high-pressure gas.

  More specifically, the swirl crushing chamber 32 is formed of a disk shape or an annular space. Along the inner peripheral wall of the swirl crushing chamber 32, seven crushing nozzles 33 and one solid-gas mixing ejector 10 are disposed at equiangular intervals. Each of the pulverizing nozzles 33 and the solid-gas mixing ejector 10 is arranged to perform high-speed gas injection in the same rotational direction. A high pressure working gas (gas) is supplied from a high pressure working gas (gas) supply device 40 to each of the crushing nozzles 33 and the drive nozzle 20 of the solid-gas mixing ejector 10.

  In the center of the bottom of the swirl crushing chamber 32, a substantially conical center convex portion 35 is formed. A cylindrical fine powder discharge port 36 is erected coaxially above the center convex portion 35. The pulverized material is introduced from the pulverized material supply unit 37 into the supply space 22 and is ejected at high speed into the swirl pulverization chamber 32 by the ejector 10. The crushed material injected into the pulverizing chamber 32 is crushed and pulverized by collision between particles by a high-speed swirling flow formed by the injection of the pulverizing nozzle 33 and one solid-gas mixing ejector 10. The fine powder (fine powder) is led to a fine powder discharge port 36 on the center convex portion 35.

  The jet mill of the above embodiment can increase the spraying speed of the powdery material that is the pulverized material by using the solid-gas mixing ejector of the present invention, thereby improving the crushing efficiency.

  As described above, the present invention has been described based on the typical embodiments. However, the present invention can have various modes other than those described above. For example, this invention can be used suitably other than a jet mill in the use which injects a powdery body at high speed.

  In a solid-gas mixing ejector in which a powdery body is entrained in a high-pressure working gas ejected from a drive nozzle and jetted at high speed, the kinetic energy of the working fluid is efficiently used for acceleration driving of the powdery body, thereby It is possible to provide a solid-gas mixing ejector that can jet a body at high speed. Moreover, the jet mill which improved the crushing efficiency can be provided by raising the injection speed of the powdery body which is a crushing material.

It is principal part sectional drawing which shows one Embodiment of the solid-gas mixing ejector by this invention. It is principal part sectional drawing which shows another embodiment of the solid-gas mixing ejector by this invention. It is an abbreviated cross section which shows the principal part of the jet mill using the solid-gas mixing ejector by this invention. FIG. 4 is an abbreviated cross-sectional view showing a portion taken along line AA in FIG. 3. It is principal part sectional drawing which shows another embodiment of the conventional solid-gas mixing ejector by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ejector 11 Unequal-diameter guide pipe 12 Inlet port 13 Outlet port S1 Intake side section S2 Exhaust side section 20 Drive nozzle 22 Powder space supply space 30 Jet mill 32 Swivel pulverization chamber 33 Grinding nozzle 35 Center convex part 36 Fine powder Body outlet 37 Crushed material supply unit 40 High-pressure working gas (gas) supply device

Claims (6)

The suction port opens in front of the injection nozzle of the drive nozzle that injects the high-pressure working gas, and the high-pressure working gas introduced into the suction port is led to the discharge port while causing flow rate changes due to narrowing and widening of the flow path. An unequal-diameter conduit for injection and discharge is provided, and the powdery substance introduced upstream of the suction port is guided to the unequal-diameter conduit along with the working gas so as to be jetted from the discharge port at a high speed. In the solid-gas mixing ejector
The non-equal-diameter guide pipe is connected to the intake side section where the flow path diameter gradually increases toward the upstream suction port, and to the downstream end of the intake side section, and the flow path diameter from the downstream end toward the discharge port. Is formed coaxially with the exhaust side section that gradually expands,
Each intake side section exhaust side section, with to such an enlarging shape of channel diameter over the entire length of the boundary both sections are in contact to the suction port and the discharge port is gradually increased, the flow path of the exhaust side section for all channels length The length ratio is 80% or more,
For both the intake side section and the exhaust side section, the change in the flow path diameter of each section is defined by an arc, and the change in the flow path diameter of the intake side section is defined by a single arc having a first radius of curvature. And a change in the flow path diameter of the exhaust side section is defined by a single arc having a second radius of curvature larger than the first radius of curvature,
The arc having the first radius of curvature and the arc having the second radius of curvature both have a center on the same line passing through the boundary, and the arcs are connected on the same line. Mixed ejector.   2. The solid-gas mixed ejector according to claim 1, wherein the flow path length of the intake-side section is the same as the diameter of the intake port or at least 0.8 times to less than 2 times the diameter.   3. The solid-gas mixed ejector according to claim 1, wherein the suction port diameter is 1.5 to 3 times the flow path diameter at the boundary. The solid-gas mixing ejector according to any one of claims 1 to 3 , wherein the second radius of curvature is set to 25 to 50 times the first radius of curvature. Solid-gas mixed ejector according to any one of claims 1 to 4, characterized in that said suction port is expanded to an outer diameter of the unequal径導flow tube. A jet that forms a high-speed gas swirl flow by injecting a high-pressure gas into a circular or annular pulverization chamber, and that causes finely pulverized crushing by injecting and supplying a powdery material as a pulverizer together with the high-pressure gas into the pulverization chamber A jet mill characterized in that, in the mill, the powdery body is injected and supplied into the pulverization chamber using the solid-gas mixing ejector according to any one of claims 1 to 5 .

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