Powder supply nozzle, airflow-type crusher, and powder supply method

Abstract

To provide a powder supply nozzle, an airflow-type crusher, and a powder supply method capable of performing a stable crushing process by suppressing closing of powder and continuously and stably supplying the powder even during crushing of the powder easily closed by a conventional method as the powder is low in fluidity.SOLUTION: A powder supply nozzle comprises: a dispersion assist gas injection pipe having a dispersion assist gas injection port for injecting a dispersion assist gas to powder; a suction pipe for sucking first mixed fluid obtained by dispersing the powder in the dispersion assist gas by means of the dispersion assist gas; a fluid injection part including an introduction part having a powder introduction pipe for introducing the first mixed fluid sucked from the suction pipe to a compressed gas and an injection port for injecting second mixed fluid containing the first mixed fluid and the compressed gas to the outside; and an air pipe for introducing the compressed gas to the introduction part. The suction pipe includes a first mixed fluid suction port for sucking the first mixed fluid and a connection port connected to the powder introduction pipe.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a powder supply nozzle, an air flow pulverizer, and a powder supply method that can stably supply various powders such as metals, ceramics, inorganic compounds, and organic compounds when the powders are pulverized and finely milled in an air flow using an air flow pulverizer. [Background technology]

[0002] A jet pulverizer described in Patent Document 1 has been known as an airflow pulverizer for pulverizing and finely grinding powders such as metals, ceramics, inorganic compounds, and organic compounds. This jet pulverizer has a pulverizing chamber in a casing and a classification chamber above it, and supplies powder to the outer periphery of the pulverizing chamber together with an airflow from a powder supply nozzle provided on the peripheral wall of the pulverizing chamber to rotate the powder. A jet airflow is sprayed from multiple air injection nozzles toward the swirling powder, and the powder is pulverized by collisions between particles and with the high-pressure jet airflow. In this method, there are basically no parts that wear out due to pulverization, so there is a low possibility of contamination, and it is particularly effective when it is required to pulverize the powder to be processed while maintaining its high purity without introducing impurities.

[0003] In addition, in Patent Document 1, the pulverized material is flowed into a classification chamber after being pulverized, and the pulverized material is centrifuged into fine powder and coarse powder by rotating in the classification chamber. The fine powder that moves to the center of the classification chamber is discharged from an exhaust pipe formed in the top wall of the classification chamber, and the coarse powder is returned from the classification chamber through a powder return passage on the outer periphery of the classification chamber into the air injection nozzle and injected again into the crushing chamber together with air, and is repeatedly crushed in the crushing chamber to become fine powder.

[0004] In the above-mentioned jet mill, the crushed material is classified after crushing, and the coarse powder that has moved to the outer periphery of the classification chamber is returned to the inside of the air injection nozzle. This reduces the amount of coarse powder remaining in the classification chamber, making it possible to prevent coarse powder from being mixed into the fine powder product, and thus making it possible to obtain a product of the desired particle size.

[0005] These air flow type mills have a hopper connected to the powder supply pipe of the powder supply nozzle, and the powder to be crushed is temporarily stored in the hopper. Air is then sprayed from the powder supply nozzle into the crushing chamber, generating negative pressure, which sucks the powder in the hopper through the powder supply pipe and supplies it to the crushing chamber.

[0006] However, in this supply method, the hopper has a tapered shape that tapers from the opening where the powder is introduced to the inlet where the powder is introduced into the powder supply pipe. Therefore, the powder gradually becomes densely packed in the hopper due to its own weight and negative air pressure, causing blockage, and it is no longer sucked in by the negative air pressure, making it impossible to continuously supply the powder to the grinding chamber, which causes the problem of being unable to perform the grinding process stably. This blockage tends to occur frequently, especially when trying to process powder with low fluidity.

[0007] Therefore, in the air flow mill described in Patent Document 2, a suction tube is used instead of a hopper, and the powder in the container is sucked in (e.g., upward) by the suction tube and supplied to the grinding chamber from the powder supply nozzle. This proposes a powder supply method that makes it difficult for the powder to clog even when the powder has low fluidity, and enables stable grinding (disintegration) processing while steadily supplying the powder continuously. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 11-179228 [Patent Document 2] JP 2019-188336 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, while the above method is far less likely to cause powder clogging than the above-mentioned feeding method using a hopper, when processing powder that has very low fluidity and is extremely prone to clogging, the inside of the suction tube or the powder feed nozzle may be intermittently clogged with powder, for example, near the connection port between the suction tube and the powder feed nozzle. Furthermore, when the powder is mainly composed of particles that are prone to oxidative heat generation (for example, Fe-based fine particles), the compaction of the particles due to clogging and the supply of air due to suction occur simultaneously, which may result in heat generation or combustion at the blocked points of the powder during the powder grinding process.

[0010] Therefore, the present invention aims to provide a powder supply nozzle, an airflow type mill, and a powder supply method that prevent clogging by powder and steadily and continuously supply powder, thereby enabling stable crushing and the like, even when crushing powder that is prone to clogging by conventional methods due to its low powder fluidity. Note that the "crushing process" used in the present invention includes not only a literal crushing process in which primary particles of powder are crushed into finer particles, but also a disintegration process in which, when the powder is made up of secondary particles that are aggregates of primary particles, the secondary particles are broken down into primary particles, and the same applies in the following description. [Means for solving the problem]

[0011] In order to solve the above problems, the powder supply nozzle of the present invention comprises a dispersion assist gas injection tube having a dispersion assist gas injection port for injecting a dispersion assist gas into the powder, a suction tube for sucking in a first mixed fluid in which the powder has been dispersed in the dispersion assist gas by the dispersion assist gas, an introduction section having a powder introduction tube for introducing the first mixed fluid sucked from the suction tube into a compressed gas, and a fluid injection section having an injection port for injecting a second mixed fluid containing the first mixed fluid and the compressed gas to the outside, and an air supply tube for introducing the compressed gas into the introduction section, and the suction tube has a first mixed fluid suction port for sucking in the first mixed fluid and a connection port connected to the powder introduction tube.

[0012] The dispersion assist gas ejection port may be disposed so as to eject the dispersion assist gas toward the powder below the first fluid mixture suction port, and the first fluid mixture suction port may open downward.

[0013] The dispersion assist gas ejection port may be open downward above the powder.

[0014] The first mixed fluid suction port may be disposed so as to protrude from within the dispersion assist gas jetting pipe so as to be surrounded by the dispersion assist gas jetting port.

[0015] The dispersion assist gas ejection port may be open upward below the powder.

[0016] In order, the air supply pipe, the introduction section, and the nozzle may be arranged in a straight line, the direction of travel of the compressed gas and the direction of suction of the first mixed fluid containing the powder and the dispersion assist gas intersect at the introduction section, and the first mixed fluid may be sucked in by negative pressure generated by the compressed gas passing through the air supply pipe, the introduction section, and the nozzle in a straight line.

[0017] The suction tube may be a metal or plastic tube.

[0018] The plastic tube may be flexible.

[0019] In order to solve the above problems, the air flow pulverizer of the present invention is an air flow pulverizer equipped with the powder supply nozzle of the present invention, and equipped with a pulverization chamber into which the second mixed fluid jetted from the jet port is introduced and which pulverizes the powder in the second mixed fluid.

[0020] The air flow mill of the present invention may include a powder storage section for storing the powder used in forming the first mixed fluid.

[0021] The air flow pulverizer of the present invention may be provided with a position movement unit that moves at least one of the powder storage unit, the first mixed fluid suction port, and the dispersion assist gas jet port while maintaining the relative positions of the first mixed fluid suction port and the dispersion assist gas jet port.

[0022] The air flow pulverizer of the present invention may include a powder transport section that transports the powder used in forming the first mixed fluid.

[0023] In order to solve the above-mentioned problems, the powder supply method of the present invention is a powder supply method using a powder supply nozzle, the powder supply nozzle comprising: a dispersion assist gas injection tube having a dispersion assist gas injection port for injecting a dispersion assist gas into the powder; a suction tube for sucking in a first mixed fluid in which the powder has been dispersed in the dispersion assist gas by the dispersion assist gas; an introduction section having a powder introduction tube for introducing the first mixed fluid sucked from the suction tube into a compressed gas; and a fluid injection section having an injection port for injecting a second mixed fluid containing the first mixed fluid and a compressed gas to the outside; and an air supply tube for introducing the compressed gas into the introduction section, The method includes a first mixed fluid suction port that sucks in a first mixed fluid, an air supply process having a connection port connected to a powder introduction tube and supplying compressed gas from an air supply tube to an injection port via an introduction section, a powder pre-dispersion process in which a dispersion assist gas is injected from a dispersion assist gas injection tube onto powder located below the first mixed fluid suction port to form a first mixed fluid containing the powder and the dispersion assist gas, a suction process in which the first mixed fluid is sucked in from the first mixed fluid suction port by negative pressure generated by the air supply process, an introduction process in which the first mixed fluid is introduced into the compressed gas at the introduction section to obtain a second mixed fluid, and an injection process in which the second mixed fluid is injected from the injection port to the outside.

[0024] The powder supplying method of the present invention may include a powder storing step of storing powder used in forming the first mixed fluid.

[0025] The powder supplying method of the present invention may include a transporting step of transporting powder used in forming the first mixed fluid.

[0026] The powder supply method of the present invention may satisfy the following formula (1) when the injection flow rate of the dispersion assist gas from the dispersion assist gas injection port is La (L / min) and the suction flow rate of the first mixed fluid sucked in from the first mixed fluid suction port is Lb (L / min).

[0027] [Formula 1] La ≦ Lb Equation (1)

[0028] The dispersion assist gas may be an oxygen-containing gas or an inert gas. Effect of the Invention

[0029] By using the powder supply nozzle of the present invention, even when a powder that is prone to clogging by conventional methods due to its low powder fluidity is pulverized, clogging by the powder can be prevented and the powder can be stably and continuously supplied, thereby enabling stable pulverization, etc. Furthermore, even when the powder is mainly composed of particles that are prone to oxidative heat generation (e.g., Fe-based fine particles), heat generation and combustion can be prevented during the powder supply process. [Brief description of the drawings]

[0030] [Figure 1] 1 is a schematic cross-sectional view showing one embodiment of a powder supply nozzle of the present invention. [Diagram 2] 2 is a diagram illustrating a dispersion assist gas ejection pipe 4 and a suction pipe 5 in the powder supply nozzle of FIG. 1. FIG. [Diagram 3] 2 is a schematic cross-sectional view showing an embodiment of the powder supplying nozzle of the present invention, which is different from that shown in FIG. 1. [Figure 4] 4 is a diagram illustrating a dispersion assist gas ejection pipe 4 and a suction pipe 5 in the powder supply nozzle of FIG. 3. FIG. [Diagram 5] FIG. 4 is a schematic cross-sectional view showing an embodiment of the powder supplying nozzle of the present invention, which is different from that shown in FIGS. [Figure 6] FIG. 2 is a schematic cross-sectional view of an airflow type mill equipped with the powder supply nozzle and the position moving unit shown in FIG. [Figure 7] FIG. 2 is a schematic cross-sectional view of an air flow type mill equipped with the powder supply nozzle and the powder transport unit of FIG. 1. [Figure 8] FIG. 4 is a schematic cross-sectional view of an airflow type mill equipped with the powder supply nozzle and the powder transport unit of FIG. 3. [Figure 9]FIG. 6 is a schematic cross-sectional view of an air current mill equipped with the powder supply nozzle and the powder transport unit of FIG. 5. [Figure 10] FIG. 1 is a schematic cross-sectional view showing a powder supplying method using a powder supplying nozzle including a powder conveying section and a hopper, which is an example of a conventional technology. [Figure 11] FIG. 1 is a schematic cross-sectional view showing a powder suction method using a powder supply nozzle, which is an example of a conventional technique. [Figure 12] FIG. 4 is a schematic cross-sectional view of an air current mill in which powder is directly sucked in from a powder conveying section by the powder supply nozzle of FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A powder supplying nozzle, an air flow mill, and a powder supplying method according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0032] [1. Powder supply nozzle] 1 shows a schematic cross-sectional view of a powder supply nozzle 1a according to one embodiment of the present invention. The powder supply nozzle 1a includes a fluid injection unit 2, an air supply tube 3, a dispersion assist gas injection tube 4, a suction tube 5, and a powder introduction tube 6.

[0033] (Fluid injection part) The fluid injection unit 2 has an introduction section 21 for introducing the powder P into the compressed gas A and an injection port 22 for injecting a second mixed fluid F containing the powder P and the compressed gas A to the outside. The first mixed fluid M described later is introduced into the compressed gas A, and the first mixed fluid M and the compressed gas A are mixed to form a second mixed fluid F. In FIG. 1, the cross-sectional shape of the introduction section 21 is a rectangular room shape, but the shape is not particularly limited. For example, in consideration of the acceleration of the compressed gas A, the introduction section 21 may have an internal shape that is tapered toward the injection port 22, which is integrated with a diffuser section 34 described later. The injection port 22 may also have an internal shape that is tapered toward the outside of the injection port 22, which is integrated with the diffuser section 34 and the introduction section 21. Furthermore, the cross-sectional shape of the introduction section 21 as viewed from the injection port 22 side may be circular.

[0034] Compressed gas A is supplied to the air supply pipe 3 from the outside. For example, compressed gas A is supplied from a cylinder or compressor (not shown). In addition, as compressed gas A, an oxygen-containing gas such as compressed air, or an inert gas such as nitrogen gas or argon gas can be used. The pressure of the compressed gas can be set arbitrarily, for example, to 0.3 MPa to 0.9 MPa.

[0035] The material of the powder P is not particularly limited as long as it is one that needs to be aggregated and pulverized, or one that is used as the second mixed fluid F. For example, a wide range of examples include inorganic powders such as metals, ceramics, and inorganic compounds, powders of food materials such as wheat flour and potato starch, powders of industrial materials such as powdered resins and wood chips, and powders of other organic compounds.

[0036] (Air pipe) The air supply pipe 3 is a pipe that introduces compressed gas A into the introduction section 21. It has a Laval nozzle shape including a compressed gas inlet section 31 into which the compressed gas A enters, a throat section 32 which further compresses the compressed gas A by having an inner diameter narrower than that of the compressed gas inlet section 31, a tapered intermediate section 33 whose inner diameter tapers from the compressed gas inlet section 31 to the throat section 32, and a tapered diffuser section 34 whose inner diameter expands from the throat section 32 to the introduction section 21. Due to this shape, the compressed gas A contracts and expands as it passes through the air supply pipe 3, thereby accelerating it.

[0037] 1, the air supply pipe 3 has a Laval nozzle shape, but the present invention is not limited to this shape, and other shapes, such as a straight pipe whose inner diameter does not change, can be adopted as long as the powder P can be supplied as the second mixed fluid F. Furthermore, the cross-sectional shape of the inner surface of the air supply pipe 3 as viewed from the injection port 22 side may be circular.

[0038] (Dispersion assist gas injection tube) The dispersion assist gas injection pipe 4 is an injection pipe that injects the dispersion assist gas C onto the powder P. When the dispersion assist gas C is injected toward the powder P below the first mixed fluid suction port 5a described below, a first mixed fluid M containing the powder P and the dispersion assist gas C is formed, and since the powder P is well dispersed and does not contain small lumps in the first mixed fluid M, if this first mixed fluid M is sucked from the first mixed fluid suction port 5a, the powder P can be sent to the fluid injection part 2 in a well dispersed state, and the suction pipe 5 and the powder introduction pipe 6 are not clogged with the powder P.

[0039] The dispersion assist gas C is a gas that is sprayed onto the powder P to disperse the powder P in the dispersion assist gas C to obtain the first mixed fluid M. The dispersion assist gas C can be an oxygen-containing gas such as air, or an inert gas such as nitrogen gas or argon gas. Since the dispersion assist gas C is sucked into the suction tube 5 together with the powder P, if the powder P is mainly composed of particles that are prone to oxidative heat generation (e.g., Fe-based fine particles), there is a risk of heat generation or combustion if the powder P should become clogged in the suction tube 5 or the like. From the viewpoint of preventing this, it is preferable to use an inert gas such as nitrogen gas or argon gas.

[0040] (1st mixed fluid M) The first mixed fluid M is a fluid in which the powder P is dispersed in the dispersion assist gas C. When the ratio of the dispersion assist gas C to the powder P is the "content density of the powder P (= mass of the powder P / volume of the powder P and the dispersion assist gas C)" and the "bulk density" of the powder P is the "mass (g) of the powder P / (volume (mL) of the powder P+volume (mL) of the air contained between the particles of the powder P)," the "content density of the powder P" of the first mixed fluid M is 1 / 100 to 1 / 10000 of the "bulk density" of the powder P, preferably. Preferably, it is 1 / 200 to 1 / 5000, and more preferably 1 / 300 to 1 / 2000. If the "content density of powder P" of the first mixed fluid M is too small, the amount of powder P to be pulverized decreases, and if the "content density of powder P" is too large, the dispersion effect of powder P in the first mixed fluid M decreases, and there is a risk of the suction tube 5 and the powder introduction tube 6 being clogged with powder P. Therefore, it is preferable that the ratio of the "content density of powder P" to the "bulk density" of powder P is within the above range.

[0041] From the viewpoint of preventing the powder P from scattering to the surroundings due to the ejection of the dispersion assist gas C, the ejection flow rate of the dispersion assist gas C can satisfy the following formula (1) when the ejection flow rate of the dispersion assist gas C is La (L / min) and the suction flow rate of the first mixed fluid M sucked from the first mixed fluid suction port 5a is Lb (L / min). By making the suction flow rate greater than the ejection flow rate or making the suction flow rate and the ejection flow rate the same, scattering of the powder P can be prevented.

[0042] La ≦ Lb Equation (1)

[0043] The arrangement of the dispersion assist gas injection pipe 4 is not particularly limited as long as it can form a first mixed fluid M containing the powder P and the dispersion assist gas C, and the formed first mixed fluid M can be quickly sucked from the first mixed fluid suction port 5a. The dispersion assist gas injection port 4a can open in either an upward or downward direction. Here, "upward" and "downward" include not only the vertical direction, but also "diagonally upward" and "diagonally downward", respectively.

[0044] 1 and 5, when the dispersion assist gas C is injected downward (in the case of FIG. 1) or upward (in the case of FIG. 5) from the dispersion assist gas injection port 4a toward the powder P below the first mixed fluid suction port 5a contained in the powder storage section 8, a first mixed fluid M in which the powder P is dispersed in the dispersion assist gas C is formed below the first mixed fluid suction port 5a. Since the first mixed fluid M is formed directly below the first mixed fluid suction port 5a, the first mixed fluid M is quickly sucked into the suction tube 5.

[0045] Regarding the arrangement of the dispersion assist gas injection pipe 4 relative to the suction pipe 5, for example, three modes shown in Figs.

[0046] (Powder supply nozzle 1a shown in Figures 1 and 2) Fig. 2(a) is a cross-sectional view seen from above of the cross section cut along dotted line G in Fig. 1. As shown in this figure, the dispersion assist gas injection pipe 4 shown in Fig. 1 is disposed so as to cover the periphery of the suction pipe 5 above the powder P. The dispersion assist gas injection port 4a is shaped and disposed so as to surround the periphery of the first mixed fluid suction port 5a, and opens in the same direction as the first mixed fluid suction port 5a (Fig. 1).

[0047] Furthermore, the first mixed fluid suction port 5a may be disposed so as to protrude from within the dispersion assist gas jetting pipe 4 while being surrounded by the dispersion assist gas jetting port 4a, that is, the first mixed fluid suction port 5a may protrude so as to be closer to the first mixed fluid M than the dispersion assist gas jetting port 4a (FIG. 1). If the first mixed fluid suction port 5a protrudes in this manner, the suction of the first mixed fluid M into the first mixed fluid suction port 5a is not hindered by the dispersion assist gas C jetted from the dispersion assist gas jetting port 4a. The degree of protrusion is not particularly limited, but if the first mixed fluid suction port 5a protrudes from the dispersion assist gas jetting port 4a by about 0 to 10 mm, it is possible to prevent the suction of the first mixed fluid M into the first mixed fluid suction port 5a from being hindered.

[0048] Figures 2(b) and 2(c) are cross-sectional views showing the arrangement of the dispersion assist gas injection pipe 4 in an embodiment different from that shown in Figure 1. Even when the first mixed fluid suction port 5a does not protrude beyond the dispersion assist gas injection port 4a and these ports are flush with each other as in Figure 2(b), it is possible to prevent the suction of the first mixed fluid M into the first mixed fluid suction port 5a from being hindered.

[0049] However, when the dispersion assist gas ejection port 4a protrudes further than the first mixed fluid suction port 5a as shown in FIG. 2(c), a portion of the dispersion assist gas C ejected from the dispersion assist gas ejection port 4a is directly sucked in through the first mixed fluid suction port 5a, which may hinder the suction of the first mixed fluid M into the first mixed fluid suction port 5a.

[0050] (Powder supply nozzle 1b shown in Figures 3 and 4) Unlike the powder supply nozzle 1a, the powder supply nozzle 1b shown in Fig. 3 is arranged so that the dispersion assist gas jet port 4a opens downward from the vicinity of the first mixed fluid suction port 5a toward the powder P directly below the first mixed fluid suction port 5a. The dispersion assist gas jet pipe 4 and the suction pipe 5 may be fixed by a piping support member 15 so that the arrangement of the dispersion assist gas jet port 4a and the first mixed fluid suction port 5a can be fixed.

[0051] Unlike the powder supply nozzle 1a, in the case of the powder supply nozzle 1b, regardless of whether the first mixed fluid suction port 5a or the dispersion assist gas ejection port 4a is closer to the first mixed fluid M, the dispersion assist gas C ejected from the dispersion assist gas ejection port 4a does not hinder the suction of the first mixed fluid M into the first mixed fluid suction port 5a.

[0052] For example, as shown in FIG. 3, the distance to the first mixed fluid M of the first mixed fluid suction port 5a and the dispersion assist gas jet port 4a may be the same, or as shown in FIG. 4(a), the first mixed fluid suction port 5a may be closer to the first mixed fluid M than the dispersion assist gas jet port 4a, or as shown in FIG. 4(b), the dispersion assist gas jet port 4a may be closer to the first mixed fluid M than the first mixed fluid suction port 5a.

[0053] (Powder supply nozzle 1c shown in Figure 5) Unlike the powder supply nozzles 1a and 1b, in the case of the powder supply nozzle 1c shown in Figure 5, the dispersion assist gas injection pipe 4 is arranged below the powder storage section 8 so that the dispersion assist gas injection port 4a faces the first mixed fluid suction port 5a through the powder P, the bottom surface of the powder storage section 8 is open, and the dispersion assist gas injection port 4a opens upward from the bottom surface of the powder storage section 8.

[0054] The arrangement of the dispersion assist gas injection pipes 4 in the powder supply nozzles 1a, 1b, and 1c is such that the first mixed fluid M formed by the dispersion assist gas C is quickly sucked into the first mixed fluid suction port 5a. In the case where the dispersion assist gas injection port 4a is arranged to open upward from the bottom surface of the powder storage section 8 (FIG. 5), a mesh (with a mesh size of about 50 μm to 250 μm) may be provided in the dispersion assist gas injection port 4a as necessary in order to prevent the powder P from dropping and entering the dispersion assist gas injection pipe 4. In the powder supply nozzles 1a, 1b, and 1c, the cross-sectional shape of the dispersion assist gas injection port 4a as viewed from the injection port side is not particularly limited, and any shape such as a circle, an ellipse, or a polygon can be used.

[0055] Here, as in the case of the powder supply nozzles 1a and 1b, when the dispersion assist gas jetting port 4a is jetted downward from above onto the powder P in the powder storage section 8, the dispersion assist gas jetting port 4a for jetting the dispersion assist gas C can be provided near the first mixed fluid suction port 5a. If the dispersion assist gas jetting port 4a is located near the first mixed fluid suction port 5a, the dispersion assist gas jetting port 4a and the first mixed fluid suction port 5a can be brought close to the powder P contained in the powder storage section 8, so that the formed first mixed fluid M can be quickly sucked in.

[0056] The material of the dispersion assist gas injection pipe 4 is not particularly limited as long as it can eject the dispersion assist gas C. For example, glass, ceramics, metals such as iron, iron alloys, aluminum, aluminum alloys, and stainless steel, and plastics such as polyvinyl chloride resin, polyethylene resin, polypropylene resin, polyolefin resin, polyester resin, polycarbonate resin, acrylic resin, polyether ether ketone resin, nylon resin, urethane resin, and fluororesin can be used for the dispersion assist gas injection pipe 4.

[0057] These materials can be appropriately selected depending on the type of powder P to be pulverized. When the powder P is a metal or metal oxide, a material that is highly wear-resistant and inactive can be selected so as not to cause impurities to be mixed into the pulverized material and not to oxidize or reduce the metal. Similarly, when the powder P is a food material such as wheat flour or potato starch, a material that is harmless to the human body can be appropriately selected. When the dispersion assist gas injection pipe 4 deteriorates, it is sufficient to replace it with a new one as appropriate.

[0058] Furthermore, if a transparent or semi-transparent injection tube is used as the dispersion assist gas injection tube 4, the formation state of the first mixed fluid M and the suction state at the first mixed fluid suction port 5a can be visualized. Specifically, a glass tube or a transparent or semi-transparent resin tube (such as a fluororesin (PFA) tube, a polyester (PET) tube, a polycarbonate tube, or an acrylic tube) can be suitably used as such a transparent or semi-transparent dispersion assist gas injection tube 4, and among them, a transparent or semi-transparent fluororesin (PFA) tube is preferable in terms of having relatively high heat resistance and appropriate strength and durability. Furthermore, in order to efficiently form the first mixed fluid M from the powder P, it is preferable that the dispersion assist gas injection tube 4 does not have any opening through which gas can enter and exit, other than the dispersion assist gas injection port 4a.

[0059] (suction tube) The suction tube 5 is a suction tube that sucks the powder P in the state of a first mixed fluid M. The first mixed fluid M sucked into the suction tube 5 is introduced into the introduction section 21 via a powder introduction tube 6 described later.

[0060] The suction tube 5 can also include a first mixed fluid suction port 5a that sucks in the powder P as a first mixed fluid M, and a connection port 5b that is connected to the powder introduction tube 6. By bringing the first mixed fluid suction port 5a and the dispersion assist gas ejection port 4a close to the powder P contained in the powder storage section 8, a first mixed fluid M containing the powder P and the dispersion assist gas C is formed, and the first mixed fluid M can be sucked from the first mixed fluid suction port 5a by the negative pressure generated in the suction tube 5.

[0061] If a gap occurs at the connection between the suction tube 5 and the powder introduction tube 6, the suction flow rate from the first mixed fluid suction port 5a decreases, making it impossible to sufficiently suction the first mixed fluid M, and the suction flow rate Lb (L / min) of the first mixed fluid M falls below the injection flow rate La (L / min) of the dispersion assist gas C, which may cause the powder P to scatter to the surroundings due to the injection of the dispersion assist gas C. For this reason, it is preferable that the connection between the connection port 5b and the powder introduction tube 6 is in close contact. For example, the connection port 5b and the powder introduction tube 6 can be connected to each other by using a connector so that they are in close contact. Also, as shown in FIG. 1, the connection part 61 of the powder introduction tube 6, which is the connection part between the powder introduction tube 6 and the connection port 5b, has an inner diameter that tapers from the suction tube 5 toward the introduction part 21, and the outer diameter of the connection port 5b can be made smaller than the inner diameter of the open end of the connection part 61 on the suction tube 5 side and larger than the inner diameter of the connection part 61 on the introduction part 21 side. As a result, the connection port 5b can be inserted into the suction tube 5 side of the connection part 61, without being inserted into the introduction part 21 side of the connection part 61, so that there is no gap between the outer peripheral surface of the connection port 5b and the inner peripheral surface of the connection part 61 and they are tightly attached to each other, preventing scattering of the powder P. In this way, the suction tube 5 and the powder introduction tube 6 can be connected directly or indirectly, and further, the suction tube 5 and the powder introduction tube 6 can be fixed by a fixing means such as an adhesive or a tape to maintain the connected state.

[0062] Here, the first mixed fluid suction port 5a can open downward. Here, "downward" includes not only vertically downward but also "diagonally downward". For example, in FIG. 1, the dispersion assist gas C disperses the powder P contained in the powder storage section 8 into a first mixed fluid M that does not contain lumpy or large aggregated powder P. The first mixed fluid suction port 5a opens downward and maintains a moderate distance from the powder P, so that the lumpy powder P or the powder P containing large aggregates is not directly sucked into the suction tube 5, and it can be adjusted to suck only the first mixed fluid M in which the powder P is well dispersed. Even if the powder P has low fluidity as an original property, after the first mixed fluid M in which the powder P is dispersed is formed by the dispersion assist gas C, the first mixed fluid M is sucked upward by the negative pressure of the suction tube 5, so that the powder P can be transported in the form of the first mixed fluid M and easily supplied to the powder supply nozzle 1.

[0063] Furthermore, the material of the suction tube 5 is not particularly limited as long as it is capable of sucking in the powder P, but for example, if it is made of metal, iron, iron alloy, aluminum, aluminum alloy, stainless steel, etc., or if it is made of plastic, polyvinyl chloride resin, polyethylene resin, polypropylene resin, polyolefin resin, polyester resin, polycarbonate resin, acrylic resin, polyether ether ketone resin, nylon resin, urethane resin, fluororesin, etc. can be used.

[0064] These materials can be appropriately selected depending on the type of powder P to be pulverized. When the powder P is a metal or metal oxide, a material that is highly wear-resistant and inactive can be selected so as not to cause impurities to be mixed into the pulverized material and not to oxidize or reduce the metal. Similarly, when the powder P is a food material such as wheat flour or potato starch, a material that is harmless to the human body can be appropriately selected. When the suction tube 5 deteriorates, it is sufficient to replace it with a new one as needed.

[0065] The shape of the suction tube 5 is not particularly limited as long as it can suck the powder P. For example, as shown in FIG. 1, a tube that is arched from the first mixed fluid suction port 5a to the connection port 5b, a tube that is curved throughout the suction tube 5, a tube that combines a straight portion with a curved portion such as an arch, etc. can be used as the suction tube 5. In addition, the cross-sectional shape of the suction tube 5 as viewed from the first mixed fluid suction port 5a side or the connection port 5b side is not particularly limited, and any shape such as a circle, an ellipse, a polygon, etc. can be used. Furthermore, the hardness of the suction tube 5 is not particularly limited, and a tube that is not easily deformable or a tube that is easily deformable can be used as appropriate.

[0066] However, if a particularly flexible plastic tube is used as the suction tube 5, it can be deformed freely, and the direction in which the first mixed fluid suction port 5a opens can be easily changed. Furthermore, if the suction tube 5 is flexible, it is easier to prevent the accumulation of the powder P by applying vibration or the like to the suction tube 5, and it becomes easier to insert the connection port 5b of the suction tube 5 into the connection part 61 of the powder introduction tube 6. As a result, there are fewer restrictions on the shape of the powder introduction tube 6, and the powder storage part 8 and the powder transport part 7 can be arranged with greater freedom, and the suction tube 5 can be easily attached and detached for cleaning and replacement.

[0067] Furthermore, the air flow mill 100 described later can be provided with a position movement unit 160 that moves at least one of the suction tube 5 and the powder storage unit 8 to change the position where the first mixed fluid M is formed in the powder storage unit 8 and the position where the formed first mixed fluid M is sucked in. In this case, if the suction tube 5 is made of a flexible plastic tube, it is possible to easily move the suction tube 5 back and forth and left and right to adjust the position where the first mixed fluid M is formed and the position where the formed first mixed fluid M is sucked in.

[0068] If a transparent plastic tube is used as the suction tube 5, the state of the powder P sucked from the first mixed fluid suction port 5a can be visualized, and the adhesion and clogging of the powder P inside the suction tube 5 can be easily confirmed. Specifically, a transparent or semi-transparent resin tube (such as a fluororesin (PFA) tube, a polypropylene tube, or a nylon tube) can be suitably used as such a transparent and flexible suction tube 5, and among them, a transparent or semi-transparent fluororesin (PFA) tube is preferable in terms of its relatively high heat resistance and moderate strength. Moreover, in order to efficiently suck the powder P without wasting negative pressure, the suction tube 5 preferably does not have any opening through which gas can enter or exit, other than the first mixed fluid suction port 5a and the connection port 5b.

[0069] (Powder introduction tube) The powder introduction tube 6 is a tube that introduces the first mixed fluid M sucked from the suction tube 5 into the introduction part 21. It is important to introduce the powder P into the introduction part 21 so that the powder P in the first mixed fluid M does not scatter to the outside, and the shape of the tube is not particularly limited, but for example, it can be provided with the tapered connection part 61 as described above, and a straight tube whose inner diameter does not change can be used as the powder introduction tube 6.

[0070] In the powder supply nozzles 1a to 1c according to one embodiment of the present invention, the air supply pipe 3, the introduction part 21, and the nozzle 22 are preferably arranged in a straight line, in that order. By arranging the air supply pipe 3, the introduction part 21, and the nozzle 22 in a straight line, the compressed gas A is injected without decreasing its moving speed. Here, since the internal shape of the air supply pipe 3 is a Laval nozzle shape, the compressed gas A is accelerated, and the compressed gas is injected from the nozzle 22 with great force.

[0071] It is also preferable that the traveling direction of compressed gas A and the suction direction B of first mixed fluid M intersect at introduction section 21. By intersecting these directions at introduction section 21, powder P is introduced into compressed gas A at introduction section 21, making it possible to easily form second mixed fluid F. In powder supply nozzle 1a shown in FIG. 1, the traveling direction and the suction direction are configured to be perpendicular to each other at introduction section 21, but these directions need not necessarily be perpendicular as long as they intersect so that second mixed fluid F is formed. The same is true for powder supply nozzles 1b and 1c.

[0072] Furthermore, the powder supply nozzles 1a to 1c are preferably ones in which the first mixed fluid M is sucked in by the negative pressure generated by the compressed gas A passing through the air supply tube 3, the introduction section 21, and the injection port 22 in a straight line. The introduction section 21, the powder introduction tube 6, and the suction tube 5 are in communication with each other, and an introduction path is secured for the first mixed fluid M to be introduced from the first mixed fluid suction port 5a to the introduction section 21. Therefore, when the compressed gas A passes through the introduction section 21 and negative pressure is generated, negative pressure is applied from the first mixed fluid suction port 5a to the introduction section 21 in this introduction path, so that the powder P can be sucked in as the first mixed fluid M. Therefore, with the above-mentioned straight line arrangement, the moving speed of the compressed gas A does not decrease, so that a negative pressure that can sufficiently suck in the first mixed fluid M can be generated. Furthermore, with the above-mentioned Laval nozzle shape, an even stronger negative pressure can be obtained by accelerating the compressed gas A.

[0073] The arrangement of the air supply pipe 3, the introduction part 21 and the injection port 22 does not have to be on a straight line as long as the first mixed fluid M can be sucked in, and these may be arranged, for example, in a curved line.

[0074] The material of the suction tube 5 is as described above, but the materials of the other components constituting the powder supply nozzle 1a can be existing materials, and an appropriate combination of stainless steel, which is resistant to corrosion and deterioration and has excellent durability, ceramics such as alumina and zirconia, which have excellent wear resistance, rubber and plastic with high sealing properties, etc. can be used.

[0075] In addition to the above-mentioned configuration, the powder supply nozzles 1a-1c may also be equipped with components such as a sealing member for preventing the powder P, compressed gas A, and second mixed fluid F from leaking from parts other than the nozzle 22, a suction tube holder that can adjust the position of the suction tube 5 relative to the powder conveying section 7 and the powder storage section 8, and a regulator or valve for adjusting the pressure (flow rate) of the compressed gas A.

[0076] The above-described powder supply nozzle 1 can mix the powder P sucked in in the form of the first mixed fluid M with the compressed gas A to form the second mixed fluid F, and can spray this second mixed fluid F to the outside, so that the powder P can be stably supplied to the grinding chamber of an air flow grinder, etc. Furthermore, the nozzle can be suitably used not only for grinding the powder P, but also for processing methods and processing devices using the second mixed fluid F, such as sandblasting.

[0077] [2. Airflow grinder] An air flow pulverizer according to one embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is a schematic cross-sectional view of an air flow pulverizer 100 according to one embodiment of the present invention. The air flow pulverizer 100 includes a powder supply nozzle 1a and a pulverization chamber 110 into which the second mixed fluid F (shown in Figs. 1, 3, and 5) injected from an injection port 22 is introduced and which pulverizes the powder P in the second mixed fluid F.

[0078] In addition, the air flow type pulverizer 100 has a pulverization chamber 110 having a circumferential wall 111, and is provided with a powder supply nozzle 1a and an air injection nozzle 120 arranged on the circumferential wall 111. The air injection nozzle 120 is usually arranged in a plurality on the circumferential wall 111, and accelerates the compressed gas A supplied from the outside and injects a high-pressure jet stream toward the outer periphery 112 in the pulverization chamber 110, generating a high-speed, high-pressure swirling flow in the pulverization chamber 110. In the powder supply nozzle 1a, the powder P is sucked in as the first mixed fluid M from the suction tube 5 through the powder introduction tube 6 by the negative pressure of the compressed gas A supplied from the outside, and the powder P is taken in the high-pressure air stream injected into the pulverization chamber 110 to become the second mixed fluid F, and the powder P is supplied to the pulverization chamber 110 as the second mixed fluid F.

[0079] The air injection nozzle 120 is not particularly limited, and any known ejector nozzle may be used as long as it can accelerate the compressed gas A. For example, a Laval nozzle that can generate a jet stream by being provided with a compressed gas inlet section 121, a throat section 122, an intermediate section 123, and a diffuser section 124, similar to the air supply pipe 3, is preferable.

[0080] The high-pressure jet stream injected by the air injection nozzle 120 forms a high-pressure swirling flow at high speed in the pulverization chamber 110, and the powder P supplied as the high-pressure second mixed fluid F to the high-pressure swirling flow is pulverized by collision with the peripheral wall 111 and collision with each other. The pulverized powder P is transferred to the classification chamber 130 provided at the upper part of the pulverization chamber 110 by the influence of the high-pressure jet stream, and is separated into coarse particles and fine powder by centrifugal force. The fine powder is then discharged from the discharge port 141 of the fine powder discharge tube 140 and collected. If the classification chamber 130 is not provided at the upper part of the pulverization chamber 110, the pulverized powder P is discharged directly from the discharge port 141. The direction of the discharge port may be upward as shown in FIG. 6 or downward, and is not particularly limited.

[0081] The airflow type pulverizer 100 can include a powder storage section 8 that stores the powder P sucked by the suction tube 5. The powder storage section 8 can store the powder P, which can eliminate the need to constantly supply the powder P to the suction tube 5. The powder storage section 8 is not particularly limited as long as it can store the powder, and the material can be, for example, iron, iron alloy, aluminum, aluminum alloy, stainless steel, etc., if it is made of metal, or polyvinyl chloride resin, polyethylene resin, polypropylene resin, polyolefin resin, polyester resin, polycarbonate resin, acrylic resin, polyether ether ketone resin, nylon resin, urethane resin, fluororesin, etc., if it is made of plastic. In addition, the shape of the powder storage section 8 can be any shape that can store the powder P, but in order to additionally supply the powder P or to continuously supply the powder P to the powder supply nozzle 1 by moving at least one of the powder storage section 8 and the first mixed fluid suction port 5a described later, it is preferable that the powder storage section 8 is a container with an open top. For example, a container having an open top, such as a box shape or a cylindrical shape, can be used.

[0082] On the other hand, when the powder storage section 8 is provided with the powder conveying section 7 described later and the powder P is continuously supplied to the powder storage section 8, it is preferable that the shape of the powder storage section 8 is a tapered shape tapering toward the bottom and a container having at least one opening on the upper surface for supplying the powder P from the powder conveying section 7 so that the supplied powder P is not stored in the powder storage section 8 but is quickly sucked in as the first mixed fluid M. For example, a container having a pyramidal or conical bottom shape tapering toward the bottom, or a container having a flat bottom, concave, or spherical surface with a size of several mm to 3 cm at the apex (bottom of the container) of the pyramid or cone can be used. The powder P supplied to these powder storage sections 8 from the powder conveying section 7 falls along the tapered inner wall of the container and gathers at the bottom of a narrow area directly below the first mixed fluid suction port 5a, so that it is easily sucked into the first mixed fluid suction port 5a as the first mixed fluid M. In order to prevent the powder P falling from the powder conveying section 7 into the powder storage section 8 from scattering, it is preferable that the open surface of the upper surface of the powder storage section 8 is closed with an upper surface member 8b provided with an opening for supplying the powder P and an opening for drawing in the dispersion assist gas injection tube 4 and the suction tube 5.

[0083] In addition, a position moving unit 160 may be provided that moves at least one of the powder storage unit 8 and the first mixed fluid suction port 5a to change the position where the first mixed fluid M is formed in the powder storage unit 8 and the position where the formed first mixed fluid M is sucked. The powder P stored in the powder storage unit 8 becomes the first mixed fluid M and is sucked from the first mixed fluid suction port 5a, but if the first mixed fluid suction port 5a is kept at a fixed position and continues to be sucked, only the powder P stored near that position will be locally reduced. Therefore, if the first mixed fluid M is continuously sucked while changing the position where the first mixed fluid M is sucked by moving at least one of the powder storage unit 8 and the first mixed fluid suction port 5a, the powder P can be reduced evenly from the entire surface of the powder P stored in the powder storage unit 8. If the suction tube 5 is made of a flexible plastic tube, the first mixed fluid suction port 5a can be easily moved back and forth and left and right.

[0084] The position moving unit 160 is not particularly limited as long as it can move at least one of the powder storage unit 8, the preliminary first mixed fluid suction port 5a, and the dispersion assist gas jet port 4a while maintaining the relative positions of the preliminary first mixed fluid suction port 5a and the dispersion assist gas jet port 4a, but an example of such a unit is an orthogonal robot.

[0085] The air flow pulverizer 100 can be equipped with a powder conveying unit 7 that supplies powder P to the first mixed fluid suction port 5a of the suction tube 5 or the powder storage unit 8 (FIGS. 7, 8, and 9). By using the powder conveying unit 7, the powder P can be continuously supplied to the first mixed fluid suction port 5a or the powder storage unit 8 without manual intervention, and the amount of powder P supplied per unit time can be kept constant. The powder conveying unit 7 is not particularly limited as long as it supplies powder P, and for example, a vibration feeder, a screw feeder, a circle feeder, or the like can be used.

[0086] Furthermore, the air flow mill 100 can directly suck in the powder P placed on the powder conveying part 7 in the state of the first mixed fluid M without using the powder storage part 8 (FIG. 12). In this case, it is preferable to set the amount of powder P supplied by the powder conveying part 7 to be equal to or less than the amount of powder P suctioned by the suction tube 5; however, for example, if the powder P that cannot be directly sucked and falls from the powder conveying part 7 is to be collected in a separate container, it is not necessarily necessary to set the amount of powder P supplied and the amount of suction.

[0087] The powder transport section 7 and the powder storage section 8 can be integrated with the pulverizer body 150 by using a fixing base (not shown) or the like for fixing them to the pulverizer body 150.

[0088] In the above description of the air flow mill 100, the air flow mill 100 is mainly provided with a powder supply nozzle 1a. However, the air flow mill 100 may also be provided with powder supply nozzles 1b and 1c as shown in FIGS.

[0089] In addition, the above-mentioned airflow type pulverizer is a swirling type airflow type pulverizer that pulverizes powder by a swirling flow in the pulverization chamber, but the present invention is not limited to this. For example, an impact plate type airflow type pulverizer that pulverizes powder transferred by an airflow using an impact plate in the pulverization chamber may also be included in the embodiments of the present invention.

[0090] [3. Powder supply method] A powder supplying method according to an embodiment of the present invention will be described with reference to Figs. 1 and 6 as an example. The powder supplying method is a method using a powder supplying nozzle 1a. The powder supplying nozzle 1a is as described above, and the introduction section 21, powder P, compressed gas A, second mixed fluid F, injection port 22, fluid injection section 2, air supply tube 3, dispersion assist gas injection tube 4, suction tube 5, powder introduction tube 6, first mixed fluid suction port 5a, connection section 61, connection port 5b, arrangement of the air supply tube 3, introduction section 21, and injection port 22 on a straight line, and the fact that the traveling direction of compressed gas A and the suction direction of powder P of the first mixed fluid M intersect at the introduction section 21 have already been described, so detailed description will be omitted here.

[0091] (Air supply process) The gas supplying step is a step of supplying compressed gas A from the gas supply pipe 3 of the powder supply nozzle 1a to the injection port 22 via the introduction part 21. This step allows the compressed gas A to be supplied, and as the compressed gas A passes through the introduction part 21, a negative pressure can be generated in the introduction path from the first mixed fluid suction port 5a to the introduction part 21, where the powder P is introduced in the form of the first mixed fluid M from the first mixed fluid suction port 5a.

[0092] (Powder pre-dispersion process) The powder preliminary dispersion process is a process in which the dispersion assist gas C is ejected from the dispersion assist gas ejection tube 4 toward the powder P located below the first mixed fluid suction port 5a to form a first mixed fluid M containing the powder P and the dispersion assist gas C. By bringing the dispersion assist gas ejection port 4a close to the powder P, the first mixed fluid M in which the powder P is dispersed in the dispersion assist gas C can be formed.

[0093] In the powder preliminary dispersion process, the dispersion assist gas C is ejected from the dispersion assist gas ejection port 4a in either an upward or downward direction toward the powder P. For example, in FIG. 1, when the dispersion assist gas C is ejected downward from the dispersion assist gas ejection port 4a toward the powder P stored in the powder storage section 8, a first mixed fluid M is formed below the dispersion assist gas ejection port 4a. Then, since the first mixed fluid suction port 5a is disposed in the vicinity of the dispersion assist gas ejection port 4a (directly above the first mixed fluid M in this case), the first mixed fluid M is quickly sucked into the suction tube 5.

[0094] If the injection flow rate of the dispersion assist gas C greatly exceeds the flow rate of the gas sucked in from the first mixed fluid suction port 5a, there is a risk that the excess dispersion assist gas C will cause the powder P to scatter to the surroundings, so it is desirable that the injection flow rate of the dispersion assist gas C does not exceed the flow rate of the gas sucked in from the first mixed fluid suction port 5a.

[0095] That is, when the jetting flow rate of the dispersion assist gas C is La (L / min) and the suction flow rate of the first mixed fluid M sucked from the first mixed fluid suction port 5a is Lb (L / min), the following formula (1) can be satisfied. By making the suction flow rate greater than the jetting flow rate or making the suction flow rate and the jetting flow rate the same, scattering of the powder P can be prevented.

[0096] La ≦ Lb Equation (1)

[0097] Furthermore, when the powder P is mainly composed of particles that are prone to oxidative heat generation (e.g., Fe-based fine particles), from the viewpoint of preventing heat generation or combustion due to blockage of the powder P in the suction tube 5, etc., it is preferable that the dispersion assist gas C be an inert gas such as nitrogen gas or argon gas.

[0098] (Suction process) The suction step is a step of sucking the first mixed fluid M through the first mixed fluid suction port 5a by the negative pressure generated in the air supply step. With the negative pressure generated in the introduction path, the first mixed fluid suction port 5a is brought close to the first mixed fluid M formed in the powder preliminary dispersion step, whereby the powder P can be sucked in the form of the first mixed fluid M.

[0099] In the suction step, the powder P is sucked upward from the first mixed fluid suction port 5a in the form of the first mixed fluid M. For example, in FIG. 1, the powder P stored in the powder storage section 8 may become clumps of powder P due to the weight of the powder P. Therefore, when the powder P is sucked horizontally or downward from the first mixed fluid suction port 5a, clumps of powder P or powder P containing large aggregates may be sucked. In contrast, when the powder P is sucked upward from the first mixed fluid suction port 5a, that is, by opening the first mixed fluid suction port 5a downward, only the first mixed fluid M dispersed in the powder preliminary dispersion step is sucked upward.

[0100] (Introduction process) The introducing step is a step of introducing the powder P in the state of the first mixed fluid M into the compressed gas A in the introducing part 21 to obtain a second mixed fluid F. By performing the suction step while maintaining the state in which the gas supplying step is being performed, the powder P can enter the introducing part 21 by the negative pressure, and therefore the powder P can be introduced into the compressed gas A passing through the introducing part 21.

[0101] (Injection process) The ejection step is a step of ejecting the second mixed fluid F to the outside from the ejection port 22. By performing the suction step and the introduction step while maintaining the state in which the gas supply step is being performed, the second mixed fluid F can be continuously obtained and the second mixed fluid F can be continuously ejected to the outside.

[0102] (Powder storage process) The powder supplying method of the present invention can include a powder storing step. The powder storing step is a step of storing the powder P to be used in the powder preliminary dispersion step, for example, by introducing and storing the powder P in the powder storage section 8. By including the powder storing step, it becomes possible to stock a constant amount of the powder P in the powder storage section 8, so that the powder P for forming the first mixed fluid M can be stably supplied.

[0103] (Transportation process) The powder supplying method of the present invention may include a powder conveying step. The powder conveying step is a step for conveying the powder P for forming the first mixed fluid M in the powder preliminary dispersion step. For example, the powder P is conveyed to the powder storage section 8 by the powder conveying section 7. The inclusion of the powder conveying step makes it possible to continuously supply the powder P, so that the first mixed fluid M can be stably formed over a long period of time.

[0104] In addition to the above-mentioned steps, the powder supply method may include other steps such as a pressure control step for controlling the pressure (air supply flow rate) of the compressed gas A, and an adjustment step for adjusting the distance between the first mixed fluid suction port 5a and the powder P in order to control the amount of powder P suctioned.

[0105] The above powder supply method sucks in the first mixed fluid M containing the powder P and the dispersion assist gas C, mixes it with the compressed gas A to produce the second mixed fluid F, and then sprays the second mixed fluid F to the outside, so that the powder P can be stably supplied to the grinding chamber of an airflow grinder, etc. Furthermore, the method can be suitably used not only for grinding the powder P, but also for processing methods and processing devices using the second mixed fluid F, such as sandblasting.

[0106] In the above explanation of the powder supplying method, a method using powder supplying nozzle 1a was described, but the powder supplying method including the above steps can also be carried out in the same manner when powder supplying nozzles 1b and 1c are used.

[0107] [Powder supply method using a powder supply nozzle equipped with a hopper] Next, as an example of the conventional technology, a powder supplying method using a powder supplying nozzle including a powder conveying section and a hopper will be described with reference to Fig. 10. Fig. 10 is a schematic cross-sectional view showing a powder supplying method using a powder supplying nozzle 10 including a hopper 9. In the powder supplying nozzle 10, the fluid injection section 2, the compressed gas inlet section 31, the Laval nozzle-shaped air supply tube 3 including a throat section 32 and an intermediate section 33, the powder introduction tube 6, and the powder conveying section 7 can have the same configuration as the powder supplying nozzle 1a and the powder conveying section 7 shown in Fig. 7, and therefore description thereof will be omitted.

[0108] In the powder supply nozzle 10, the hopper 9 includes a supply port 91 through which the powder P is supplied, and an introduction port 92 that is connected to the powder introduction tube 6 and introduces the powder P into the fluid spray unit 2. The inside of the hopper 9 has a tapered shape that tapers from the supply port 91 to the introduction port 92.

[0109] The powder P is supplied to the hopper 9 from above using the powder conveying section 7 etc. A predetermined amount of the powder P supplied to the hopper 9 is sucked from the bottom of the hopper 9 through the powder introduction pipe 6 to the introduction section 21 due to negative pressure generated by the compressed gas A passing in a straight line through the air supply pipe 3, the introduction section 21 and the nozzle 22, and the powder P is introduced into the compressed gas A in the introduction section 21 to become a second mixed fluid F, which is then sprayed to the outside from the nozzle 22, and is supplied, for example, into an air flow type pulverizer.

[0110] In the hopper 9, the powder P at the bottom is pressed by the weight of the powder P supplied from above and the negative pressure, and the powder P at the bottom of the hopper 9 is likely to be compressed and densely packed by these pressures. The powder supply nozzle 10 tries to suck the powder P in the hopper 9 by the negative pressure of the compressed gas A, but the densely packed and compressed powder is likely to lose fluidity, and once it is in this state, it is difficult to reflow. That is, the powder P sometimes clogs the inside of the hopper 9. That is, the frictional force that resists the powder P from starting to flow is sometimes higher than the suction force caused by the negative pressure. In particular, when the powder P itself has a property that is difficult to flow, the powder P often clogs the inside of the hopper 9, and there are cases where the powder P cannot be stably and continuously supplied to the powder supply nozzle 10. EXAMPLES

[0111] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0112] Example 1 In Example 1, an airflow pulverizer was used, and in this embodiment, a powder supply nozzle 1a shown in Fig. 1 was used. A soft magnetic powder with a number average particle size of 0.3 μm (composition: 70 mol% Fe-10 mol% Ni-20 mol% Co, true specific gravity = 8) was used as the powder P, and the powder supply nozzle 1a and the powder storage section 8 were installed in the pulverizer body of a tabletop airflow pulverizer (JKE-30 model, manufactured by Nippon Pneumatic Mfg. Co., Ltd.: a bag-shaped bag filter with an inner diameter of 70 mm and a length of 300 mm was connected to the recovery section of the treated powder), and pulverization processing (including disintegration processing) was performed by supplying compressed air of 0.5 MPa.

[0113] Although the configuration of the pulverizer body of the air flow pulverizer used in Example 1 is different from the configuration of the pulverizer body 150 of the air flow pulverizer 100 shown in FIG. 6, the object of the present invention can be solved by any air flow pulverizer body that basically sucks in the first mixed fluid M, powder P, etc. by utilizing the negative pressure in the part with a high flow velocity according to Bernoulli's law.

[0114] In the airflow pulverizer, a powder supply nozzle 1a was used in which a Teflon tube (registered trademark, material PFA, outer diameter 4 mm × inner diameter 3 mm × length 300 mm) was connected to a powder introduction tube 6 via a connection port 5b as the suction tube 5. The first mixed fluid suction port 5a of the suction tube 5 was disposed so as to protrude 1 mm from the inside of the dispersion assist gas injection tube 4 (outer diameter 10 mm × inner diameter 8 mm) beyond the dispersion assist gas injection port 4a so that the periphery was surrounded by the dispersion assist gas injection port 4a. In addition, both the first mixed fluid suction port 5a and the dispersion assist gas injection port 4a were disposed so as to open downward, so that the first mixed fluid M containing the powder P and the dispersion assist gas C formed by the injection of the dispersion assist gas C was quickly sucked from the first mixed fluid suction port 5a. Nitrogen gas was used as the dispersion assist gas C, and since the suction gas flow rate at the first mixed fluid suction port 5a was 3.0 L / min, the flow rate (dispersion assist gas flow rate) of the dispersion assist gas C (nitrogen gas) injected from the dispersion assist gas injection port 4a was set to 3.0 L / min (La = Lb).

[0115] The powder storage section 8 had an open top and a flat bottom surface 8a with a square shape of 90 mm sides. The powder P with a mass of 100 g was spread on the bottom surface 8a of the powder storage section 8 so that the powder thickness was about 4 mm. The dispersion assist gas C was sprayed from the dispersion assist gas spray port 4a of the dispersion assist gas spray tube 4 from above the powder P, and the powder was sucked from the first mixed fluid suction port 5a of the suction tube 5, while the dispersion assist gas spray port 4a and the first mixed fluid suction port 5a were gradually brought close to the powder. The spraying of the dispersion assist gas C formed the first mixed fluid M (powder P and dispersion assist gas C) from the powder P, and the first mixed fluid M was sucked in so as to flow quickly from the bottom to the top at the first mixed fluid suction port 5a by the operation of the air flow type pulverizer.

[0116] An orthogonal robot was used as the position movement unit 160, and a dispersion assist gas injection port 4a and a first mixed fluid suction port 5a were attached to the orthogonal robot, and the powder P stored in the powder storage unit 8 was efficiently sucked in by sequentially moving the robot back and forth and left and right.

[0117] With the above suction mode, 100 g of powder P was supplied to the airflow mill in 10 minutes (the supply rate of powder P was constant at 10 g / min). During the supply of powder P, no blockage occurred due to the powder P clogging the inside of the suction tube 5 or the powder introduction tube 6, and no heat generation or combustion of the powder P was observed. In addition, as the powder P could be continuously supplied to the grinding chamber, stable grinding processing was possible.

[0118] In the case of Example 1, the powder density of the powder P (lump) (=bulk density: powder mass (g) / (powder volume (mL) + air volume (mL) contained between powder particles) is 1 to 3 g / cm for a metal powder with a true specific gravity of 8. 3 The density of the powder P in the first mixed fluid M is about 0.0033 g / cm when the flow rate of the dispersion assist gas C is (3 L / min = 3000 mL / min) and 10 g / min of the powder P is uniformly dispersed in the first mixed fluid M. 3 (The volume of the powder is negligibly small compared to the gas.) The density of the powder P in the first mixed fluid M is 0.0033 g / cm 3 " and "Bulk density: 3g / cm3 The relationship between the powder P and the density of the powder P in the first mixed fluid M is about 1 / 900. 3 Although the bulk density is somewhat larger than 1-3 g / cm 3 Compared with sucking the lumps of powder P directly into the first mixed fluid suction port 5a, this prevents the densely packed lumps of powder P from moving inside the suction pipe 5, enabling a stable pulverization process. The same applies to Examples 2 to 4 described below.

[0119] Example 2 In Example 2, an airflow type pulverizer shown in Fig. 7 was used. In Example 2, a powder supply nozzle 1a shown in Fig. 1 was used. In this example, the position moving unit 160 was not provided, and an airflow type pulverizer equipped with a vibration feeder as the powder conveying unit 7 was used.

[0120] An upper surface member 8b having an opening was installed on the upper part of the powder storage section 8 as an intake port for the powder P supplied from the powder conveying section 7. The bottom surface of the powder storage section 8 had a tapered part shaped like a cone with a diameter of 5 cm and a hypotenuse of 7 cm, with the apex facing downward, and the apex had a circular bottom surface part with a diameter of 1 cm.

[0121] The first mixed fluid suction port 5a was positioned 2 mm above the circular bottom surface having a diameter of 1 cm so that the openings of the dispersion assist gas jet port 4a and the first mixed fluid suction port 5a both faced downward.

[0122] Without storing powder P in advance in the powder storage section 8, the airflow pulverizer was started, and the dispersion assist gas C was sprayed, and then 600 g of powder P was continuously supplied to the airflow pulverizer at a supply rate of 10 g / min using a vibration feeder, and 600 g of powder P was supplied to the airflow pulverizer in 1 hour. Other than the above, the same procedure as in Example 1 was carried out.

[0123] Also in Example 2, during the supply of the powder P, no clogging occurred due to the powder P clogging the inside of the suction tube 5 or the powder introduction tube 6, and no heat generation or combustion was observed in the powder P. Furthermore, as a result of the powder P being able to be continuously supplied to the grinding chamber for a long period of time, stable grinding processing was possible.

[0124] Example 3 In Example 3, an air flow type pulverizer shown in Fig. 8 was used. In Example 3, a powder supply nozzle 1b shown in Fig. 3 was used.

[0125] The first mixed fluid suction port 5a was arranged at a position 2 mm above the bottom surface 8a, with the suction tube 5 (outer diameter 4 mm × inner diameter 3 mm) tilted 5° with respect to the vertical direction so that the opening faces downward. The dispersion assist gas ejection port 4a was arranged at a position where the dispersion assist gas C is ejected to the powder P below the first mixed fluid suction port 5a, with the dispersion assist gas ejection port 4a tilted 10° in the opposite direction to the suction tube 5 so that the opening faces downward. The dispersion assist gas ejection port 4a was arranged so that it was 2 mm higher in the vertical direction than the first mixed fluid suction port 5a. Other than the above, the same procedure as in Example 2 was carried out.

[0126] Also in Example 3, during the supply of the powder P, no clogging occurred due to the powder P clogging the inside of the suction tube 5 or the powder introduction tube 6, and no heat generation or combustion was observed in the powder P. Furthermore, as a result of the powder P being continuously supplied to the grinding chamber for a long period of time, stable grinding processing was possible.

[0127] Example 4 In Example 4, an airflow type pulverizer shown in Fig. 9 was used. In Example 4, a powder supply nozzle 1c shown in Fig. 5 was used.

[0128] In this embodiment, an opening with a diameter of 6 mm was provided in the center of the bottom surface portion 8a, which had a diameter of 1 cm, of the powder storage portion 8 used in Example 2, and the dispersion assist gas nozzle 4a was connected so as to face upward from the back side of the bottom surface portion 8a.

[0129] The first mixed fluid suction port 5a was disposed at a position 7 mm above the opening of the bottom surface portion 8a so that the first mixed fluid M containing the powder P and the dispersion assist gas C formed by the ejection of the dispersion assist gas C could be quickly sucked in. Other than the above, the same procedure as in Example 2 was carried out.

[0130] In Example 4 as well, the first mixed fluid M (powder P and dispersion assist gas C) was formed from the powder P by the injection of the dispersion assist gas C, and the first mixed fluid M was sucked into the first mixed fluid suction port 5a so as to flow quickly from bottom to top by the operation of the air flow type pulverizer. Moreover, during the supply of the powder P, no clogging occurred due to the powder P clogging the inside of the suction tube 5 or the powder introduction tube 6, and no heat generation or combustion of the powder P was observed. Moreover, as the powder P could be continuously supplied to the pulverization chamber for a long period of time, stable pulverization processing was possible.

[0131] Comparative Example 1 In Comparative Example 1, the powder supply nozzle 10 shown in Fig. 10 was used, and the powder P (composition: 70 mol% Fe-10 mol% Ni-20 mol% Co) having the same number average particle size as in Example 1 was pulverized in the same manner as in Example 1, except that the airflow type pulverizer in which the dispersion assist gas injection tube 4 and the suction tube 5 of the powder supply nozzle 1a are attached to the position moving section 160 was changed to an airflow type pulverizer using the powder supply nozzle 10 that also uses the hopper 9 and the powder conveying section 7. That is, the powder P was supplied to the hopper 9 from the powder conveying section 7 under the same supply speed condition of 10 g / min as in Example 1, and the airflow type pulverizer was operated.

[0132] As in Example 1, the pulverization process was started with the plan of supplying 100 g of powder P in 10 minutes, but within a few seconds of the start of the process, the inside of the hopper 9 was clogged with powder P as shown in Fig. 10, and the powder P was no longer supplied to the pulverization chamber. During the pulverization process, every time the hopper 9 was clogged with powder P, it was necessary to remove the clogged part in order to supply the powder P, and it took 60 minutes to pulverize 10 g of powder P. Since the process was stopped midway, it was not possible to perform a continuous and stable pulverization process.

[0133] Comparative Example 2 In Comparative Example 2, the powder supply nozzle 20 shown in FIG. 11 was used. The powder supply nozzle 20 was used to pulverize the powder P having the same number average particle diameter of 0.3 μm as in Example 1, except that the suction of the first mixed fluid M by the combination of the dispersion assist gas injection tube 4 and the suction tube 5 of the powder supply nozzle 1a was changed to the suction of the powder P by the sole use of the suction tube 5. That is, the first mixed fluid suction port 5a was brought into contact with the powder P (thickness: about 4 mm) contained in the powder storage section 8 from diagonally above, and the powder P was sucked in diagonally upward from below by the first mixed fluid suction port 5a by operating the air flow type pulverizer. The powder P (thickness: about 4 mm) contained in the powder storage section 8 was sucked in diagonally upward from below by the first mixed fluid suction port 5a while the first mixed fluid suction port 5a of the suction tube 5 was moved back and forth and left and right in sequence (not shown).

[0134] As in Example 1, the pulverization process was started with the plan of supplying 100 g of powder P in 10 minutes, but a few minutes after the start of the process, a blockage occurred in the suction tube 5 near the connection port 5b of the suction tube 5 and the powder supply nozzle 20. When the blocked suction tube 5 was removed and replaced with a new one, a blockage occurred again in the same place a few minutes later, and an operation to remove the blockage was performed. Ultimately, it took 15 minutes to pulverize 100 g of soft magnetic powder P, and it was not possible to perform a stable pulverization process continuously.

[0135] [summary] In Examples 1 to 4, the first mixed fluid M was formed from the powder P by using the dispersion assist gas injection pipe 4 and the suction pipe 5 in combination, and it was possible to suck it upward. The first mixed fluid M was formed in advance by ejecting the dispersion assist gas C, and small lumps of the powder P were not dispersed and sucked from the powder P as they were, so the powder P was not consolidated in the suction pipe or the powder supply nozzle, and therefore no blockage occurred during the process of sucking the powder P, making it possible to perform a continuous and stable pulverization process. In addition, because nitrogen gas was used as the dispersion assist gas C, even if a blockage occurred, heat generation or combustion of the powder P at the blocked portion can be prevented, making the pulverization process (disintegration process) safer.

[0136] In the first embodiment, an orthogonal robot was used as the position moving unit 160, so that the first mixed fluid suction port and the dispersion assist gas ejection port could move over the entire bottom surface of the powder storage unit that stores the powder. As a result, the powder stored in the powder storage unit could be supplied without any waste.

[0137] In addition, in Examples 2 to 4, a vibrating feeder was used as the powder transport section, making it possible to continuously supply the magnetic powder P to the powder storage section 8. This eliminated the need to constantly replenish the powder P, and made it possible to continuously supply the powder for a long period of time.

[0138] On the other hand, in the case of Comparative Example 1, it is presumed that the main cause of clogging by the powder P is that the powder P in the hopper 9 is not dispersed but is supplied as small lumps to the powder introduction tube 6 of the powder supply nozzle 10. In addition, it is also considered that one of the causes of clogging by the powder P is that the internal structure of the hopper 9 has a tapered shape that tapers toward the suction direction of the powder P, and thus the powder P is compressed by its own weight or negative pressure and packed densely. It is easy to predict that such clogging will occur not only with the powder P used this time, but also with other powders P, and it was considered that the use of the hopper 9 would significantly hinder the grinding process, especially in the case of powder P with low fluidity.

[0139] In Comparative Example 2, the number of cloggings was significantly reduced and the powder P could be pulverized, compared to the supply method using the hopper 9 in Comparative Example 1. However, the powder P was less stable in supply than in the supply methods using the dispersion assist gas injection pipe 4 and the suction pipe 5 in combination in Examples 1 to 4.

[0140] From the results of the examples, it was found that by using the powder supply nozzle, air flow pulverizer, and powder supply method using the powder supply method according to the present embodiment, a dispersion assist gas is sprayed onto the powder to form a first mixed fluid containing the powder and the dispersion assist gas, and the first mixed fluid is sucked upward through a suction tube to supply the powder into the air flow pulverizer, so that even if the powder has low fluidity, clogging can be effectively prevented and stable pulverization processing can be achieved. Also, even if the powder is mainly composed of particles that easily generate heat by oxidation (for example, Fe-based fine particles), heat generation and combustion can be effectively prevented during the powder supply process.

[0141] Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or amended examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0142] 1a, 1b, 1c, 10, 20: powder supply nozzle, 2: fluid injection section, 3: air supply pipe, 4: dispersion assist gas injection pipe, 4a: dispersion assist gas injection port, 5: suction pipe, 5a: first mixed fluid suction port, 5b: connection port, 6: powder introduction pipe, 7: powder conveying section, 8: powder storage section, 8a: bottom section, 8b: upper surface member, 9: hopper, 9a: supply end, 9b: introduction end, 15: piping support member, 21: introduction section, 22: injection port, 31: compressed gas inlet section, 32: throat section, 33: middle section, 34: diffuser section, 6 1: Connection part, 91: Supply port, 92: Inlet port, 100: Air flow type pulverizer, 110: Grinding chamber, 111: Circumferential wall, 112: Outer periphery, 120: Air injection nozzle, 121: Compressed gas inlet part, 122: Throat part, 123: Middle part, 124: Diffuser part, 130: Classification chamber, 140: Fine powder discharge tube, 141: Discharge port, 150: Pulverizer body, 160: Position moving part, A: Compressed gas, B: Suction direction of powder P and first mixed fluid M, C: Dispersion assist gas, F: Second mixed fluid, M: First mixed fluid, P: Powder

Claims

1. a dispersion assist gas injection pipe having a dispersion assist gas injection port for injecting a dispersion assist gas onto the powder; a suction pipe for suctioning a first mixed fluid in which the powder is dispersed in the dispersion assist gas by the dispersion assist gas; an introduction unit having a powder introduction tube that introduces the first mixed fluid sucked from the suction tube into a compressed gas, and a fluid injection unit having an injection port that injects a second mixed fluid containing the first mixed fluid and the compressed gas to the outside; an air supply pipe for introducing the compressed gas into the introduction portion; Equipped with the suction pipe has a first mixed fluid suction port that sucks the first mixed fluid, and a connection port that is connected to the powder introduction pipe; and a powder supply nozzle.

2. the dispersion assist gas ejection port is disposed so as to eject the dispersion assist gas toward the powder below the first mixed fluid suction port, The powder feed nozzle of claim 1 , wherein the first fluid mixture suction port opens downward.

3. The powder supply nozzle according to claim 2 , wherein the dispersion assist gas jetting port opens downward above the powder.

4. The powder supply nozzle according to claim 3 , wherein the first mixed fluid suction port is disposed protruding from within the dispersion assist gas jetting pipe so as to be surrounded by the dispersion assist gas jetting port.

5. The powder supply nozzle according to claim 2 , wherein the dispersion assist gas jetting port opens upward below the powder.

6. 3. The powder supply nozzle according to claim 1 or 2, wherein the air supply pipe, the introduction portion, and the nozzle are arranged in a straight line, a traveling direction of the compressed gas and a suction direction of the first mixed fluid containing the powder and the dispersion assist gas intersect at the introduction portion, and the first mixed fluid is sucked in by a negative pressure generated when the compressed gas passes through the air supply pipe, the introduction portion, and the nozzle in a straight line.

7. 3. The powder delivery nozzle of claim 1 or 2, wherein the suction tube is a metal tube or a plastic tube.

8. The powder delivery nozzle of claim 7 , wherein the plastic tube is flexible.

9. An airflow type pulverizer comprising the powder supply nozzle according to claim 1 or 2, the second mixed fluid jetted from the jet port is introduced into a grinding chamber for grinding powder in the second mixed fluid.

10. 10. The air flow type mill according to claim 9, further comprising a powder storage section for storing the powder used in forming the first mixed fluid.

11. While maintaining the relative positions of the first mixed fluid suction port and the dispersion assist gas injection port, 11. The air flow type pulverizer according to claim 10, further comprising a position moving unit that moves at least one of the powder storage unit, the first mixed fluid suction port, and the dispersion assist gas injection port.

12. 10. The air flow type pulverizer according to claim 9, further comprising a powder transport unit that transports the powder used in forming the first mixed fluid.

13. 1. A method of powder delivery using a powder delivery nozzle, comprising: The powder supply nozzle includes: a dispersion assist gas injection pipe having a dispersion assist gas injection port for injecting a dispersion assist gas onto the powder; a suction pipe for suctioning a first mixed fluid in which the powder is dispersed in the dispersion assist gas by the dispersion assist gas; an introduction unit having a powder introduction tube that introduces the first mixed fluid sucked from the suction tube into a compressed gas, and a fluid injection unit having an injection port that injects a second mixed fluid containing the first mixed fluid and the compressed gas to the outside; an air supply pipe for introducing the compressed gas into the introduction portion; Equipped with the suction pipe has a first mixed fluid suction port that sucks the first mixed fluid and a connection port that is connected to the powder introduction pipe, a gas supplying step of supplying the compressed gas from the gas supply pipe through the introduction part to the injection port; a powder pre-dispersion step of injecting the dispersion assist gas from the dispersion assist gas injection pipe onto the powder located below the first mixed fluid suction port to form the first mixed fluid containing the powder and the dispersion assist gas; a suction step of suctioning the first mixed fluid through the first mixed fluid suction port by a negative pressure generated in the air supply step; an introducing step of introducing the first mixed fluid into the compressed gas in the introducing portion to obtain a second mixed fluid; an injection step of injecting the second mixed fluid from the injection port to the outside; 13. A method for supplying powder comprising:

14. The powder supplying method according to claim 13 , further comprising a powder storing step of storing the powder used in forming the first mixed fluid.

15. The powder supplying method according to claim 13 or 14, further comprising a transporting step of transporting the powder used in forming the first mixed fluid.

16. 15. The powder supply method according to claim 13 or 14, wherein when the injection flow rate of the dispersion assist gas from the dispersion assist gas injection port is La (L / min) and the suction flow rate of the first mixed fluid sucked from the first mixed fluid suction port is Lb (L / min), the following formula (1) is satisfied. La≦Lb... Formula (1)

17. 15. The powder supplying method according to claim 13, wherein the dispersion assist gas is an oxygen-containing gas or an inert gas.

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