JP4858264B2 - Powder airflow mixing apparatus and mixing method - Google Patents

Description

  The present invention relates to an airflow mixing device for a granular material that can be mixed and transported uniformly and continuously with high productivity without being crushed by a stirring blade or the like.

  Conventionally, as a mixing device for powder and granular material, a mixing device using blades as stirring means is often used. However, in this type of mixing device, the powder and particles to be mixed are pulverized by the stirring blades. There has been a problem that the quality is deteriorated, for example, the particle size, the particle size, and the particle size distribution are changed, and the physical properties of the obtained mixture of the granular materials are changed. In addition, many devices are used to mix powder particles by charging powder particles weighed at a predetermined weight ratio and rotating for a certain period of time. There is a problem that productivity is poor because the work is different. Further, when these apparatuses are used, there is a problem that a staying portion is formed in the apparatus and uniform mixing cannot be performed.

In order to solve such a problem, Patent Document 1 discloses that another airflow is supplied from a slit formed in the peripheral wall of the cylindrical tube while flowing an air flow including the granular material in the axial direction of the tapered cylindrical tube. An apparatus for introducing pressurized air containing the is described. Further, Patent Document 2 describes an apparatus capable of simultaneously sucking powder particles into a mixing tank having an air discharge port and a mixed powder discharge port and transporting, mixing and discharging the powder particles in parallel. Has been. Patent Document 3 describes an apparatus for supplying powder particles to a spherical vortex chamber into which a stream of air is introduced in a tangential direction, mixing the mixture by rotating the air stream, and discharging the mixture from an introduction pipe inserted into the spherical vortex chamber. ing. Patent Document 4 discloses that a thermoplastic resin pellet and a fatty acid metal salt are mixed at 20 ° C. to 50 ° C. and then transported at a high density (high pressure) to form a film layer of the fatty acid salt on the pellet. A method for eliminating salt shedding is described.
JP-A 63-267424 JP-A-9-155171 JP-A-6-39261 PCT / US1993 / 08004

  However, in the mixing apparatus and method described in Patent Document 1, the apparatus becomes complicated, and it is difficult to perform cleaning when changing the type of the granular material. Further, in the airflow mixing apparatus described in Patent Document 2, the powder is transported and mixed by the airflow. However, since the airflow outlet and the powder outlet are separately provided, the powder is discharged from the airflow outlet. There was a problem of being discharged. Moreover, in the mixing apparatus described in Patent Document 3, there is a problem in that the time during which the powder particles are rotated in the spherical vortex chamber varies and uniform mixing cannot be performed. Further, in the mixing method described in Patent Document 4, a device capable of generating an air flow at a high pressure is necessary to pneumatically transport the granular material at a high density (high pressure), which increases the cost. was there.

  In view of the background of the prior art, the present invention is capable of mixing and transporting powder particles uniformly and continuously with good productivity without crushing by stirring blades, etc. When changing the type of powder particles It is intended to provide an airflow mixing device for a granular material that can be easily cleaned.

  The present invention employs the following means in order to solve such problems.

  That is, the airflow mixing device for a granular material according to the present invention includes an introduction pipe for supplying an airflow containing the granular material present at a predetermined weight ratio, and an airflow in which one end is sealed and the other end includes the granular material. An airflow mixing device comprising a cylindrical tube that is a discharge port of the gas pipe, wherein the cylindrical tube is attached with the introduction pipe in the tangential direction and has a larger diameter than the introduction pipe. It is characterized by this.

A preferred embodiment of the airflow mixing device for such a granular material is:
(1) When the diameter of the introduction pipe is D, the diameter of the cylindrical pipe is 2D to 4D.
(2) The diameter of the discharge port of the cylindrical tube has a taper that is the same as the diameter of the introduction tube,
(3) When the diameter of the introduction tube is D, the axial length of the cylindrical tube toward the discharge port is 2D to 3D from the introduction tube wall;
(4) The introduction pipe is provided with a hopper for supplying the granular material,
(5) The gas that mixes and transports the granular material is at least one selected from dehumidified air, inert gas, and air;
It is.

  Moreover, the airflow mixing method of the granular material of the present invention is characterized by using such an airflow mixing device for the granular material.

  A preferable embodiment of the air-flow mixing device for such powder is that the powder is a thermoplastic resin pellet and a fatty acid metal salt.

  According to the airflow mixing device of the granular material of the present invention, the granular material can be mixed and transported uniformly and continuously with good productivity without crushing by a stirring blade or the like, and the type of the granular material is changed. It can be easily cleaned when you do.

  In particular, according to the present invention, it is suitable for mixing powder materials such as plastic materials, medical drugs, processed food materials, and the like. The mixing in the above and the discharging of the powder and particles already mixed in the powder and particle mixing space can be performed simultaneously and continuously.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic explanatory view showing the configuration of an embodiment of an airflow mixing apparatus for granular material according to the present invention. FIG. 2 is a view of a part of the introduction tube and a part of the cylindrical tube, the taper, and the discharge tube of the airflow mixing apparatus for the granular material shown in FIG. 1, and is a view perpendicular to the axial direction of the cylindrical tube. FIG. 3 is a view of a part of the introduction tube and a part of the cylindrical tube, the taper, and the discharge tube of the airflow mixing device for the granular material shown in FIG. 1, and is a view in the horizontal direction with respect to the axial direction of the cylindrical tube. FIG. 4 is a diagram showing an example of an embodiment of the present invention.

  In FIG. 1, an airflow mixing device 1 of the present granular material includes an airflow generating device 2, granular material supply devices 3 a and 3 b, a hopper 4, an introduction tube 5, a cylindrical tube 6 having a tapered portion 7, and a discharge tube 8. . 2 and 3, the introduction tube 5, the cylindrical tube 6, the taper portion 7, and the discharge tube 8 correspond to those in FIG.

  In the present invention, the granular material is weighed at a predetermined weight ratio by the granular material supply devices 3 a and 3 b and supplied to the hopper 4. The granular material supplied to the hopper 4 is premixed while being transported through the introduction pipe 5 by the airflow generated by the airflow generator 2. The air stream containing the granular material transported and premixed through the introduction pipe 5 is introduced into the cylindrical pipe 6 from the tangential direction of the cylindrical pipe, and is rotated along the wall of the cylindrical pipe 6. Mixed. The airflow containing the powder and particles mixed in the cylindrical tube 6 passes through the tapered portion 7 of the cylindrical tube 6 and is discharged from the discharge tube 8.

  The embodiment of the present invention shown in FIG. 1 will be described below.

  The airflow generation device 2 in the present invention may be anything as long as it satisfies a predetermined flow rate and pressure, and for example, a blower or a compressor can be used. Any type of airflow may be used, but for example, dehumidified air, nitrogen gas, air, or the like can be used. The flow rate of the air flow is preferably 20 to 30 m / sec when, for example, nylon resin pellets, which are thermoplastic resins, are transported by the air flow, but can be selected depending on the processing amount and specific gravity of the granular material.

  The granular material supply devices 3a and 3b in the present invention may be anything as long as they can quantitatively supply the granular material, and for example, a weight-type screw feeder, a positive displacement screw feeder, a rotary valve, or the like can be used. However, when using a positive displacement screw feeder or a rotary valve that does not detect the weight, it is preferable to know the relationship between the screw rotation speed and the discharge amount in advance.

  The hopper 4 in the present invention may be anything as long as it can supply powder particles to the introduction pipe 5, and the diameter of the discharge port 8 can be selected according to the processing amount and particle diameter of the powder particles. Further, if the granular material has a characteristic of bridging in the hopper 4, a knocker may be attached to the outside of the hopper 4 to prevent bridging.

 The diameter of the introduction tube 5 in the present invention can be selected depending on the specific gravity, particle diameter, and processing amount of the granular material. The introduction pipe 5 may be made of any material such as metal or plastic, but is preferably a material obtained by hardening stainless steel in order to prevent wear of the powder or rust from entering the powder.

  If the diameter of the cylindrical tube 6 in the present invention is too small, the air flow including the powder particles does not rotate in the cylindrical tube, and if it is too large, the flow velocity of the air flow in the cylindrical tube decreases and the particles are not transported and stays. Since it will obstruct | occlude eventually, 2D-4D is preferable with respect to the diameter D of an inlet tube.

  The installation position of the introduction pipe 5 in the axial direction of the cylindrical pipe 6 is preferably a position close to the sealing side of the cylindrical pipe 6, and the inner wall of the introduction pipe 5 has a distance of 0D from the inner wall on the sealing side of the cylindrical pipe 6. It is preferable to install at a position of about 0.5D.

  If the length of the cylindrical tube 6 is too short, the rotation time of the air flow including the powder particles is shortened and uniform mixing cannot be performed. If the length is too long, the powder particles are caused by energy loss due to rotation or the like at the stage toward the discharge port. It is preferable that the length from the inner wall of the introduction pipe 5 on the discharge port side of the cylindrical pipe 6 is 2D to 3D with respect to the diameter D of the introduction pipe 5.

  The diameter on the discharge side of the tapered portion 7 installed on the discharge port side of the cylindrical tube 6 in the present invention is preferably the same as the diameter of the discharge tube 8. The angle of the taper portion 7 is preferably in the range of 45 degrees to 90 degrees in order to smoothly transport the airflow including the granular material to the discharge port 8.

Also, the material of the cylindrical tube 6 and the tapered portion 7 may be any metal or plastic as in the case of the introduction tube 5, but in order to prevent abrasion with the granular material, rust and the like from being mixed into the granular material, What hardened stainless steel is preferable.
Further, the cylindrical tube 6 is not limited to a cylindrical shape, and as shown in FIG. 4, the tapered portion 7 of the cylindrical tube 6 may be made as long as possible so as to have a substantially truncated cone shape.

  Since the diameter of the discharge pipe 8 is transported at the same flow rate as the airflow in the introduction pipe 5, the diameter is preferably the same as that of the introduction pipe 5.

  Next, the effects of the present invention will be specifically described by way of examples.

  In this example, nylon resin pellets and calcium stearate were mixed. In this example, the nylon resin pellets and calcium stearate obtained from the discharge pipe were sampled, and the weight of calcium stearate adhering to the nylon resin pellets was confirmed. The implementation conditions and the evaluation method will be described in detail below.

[Nylon resin pellet characteristics]
It describes about the used nylon resin pellet.
Material: Nylon resin pellet (Toray Industries, Inc. Amilan (R) CM1016G30FB1)
Particle size: φ3mm × 3.5mmL
Specific gravity: 1350kg / m ³

[Calcium stearate properties]
The calcium stearate used is described.
Material: Calcium stearate (Katayama Chemical Co., Ltd.)
Particle size: Fine powder (size passing through 99% of 200 mesh)
Specific gravity: 0.15 to 0.25 g / ml

[Conditions]
Describe the implementation conditions.
Nylon resin pellet throughput: 500 kg / h
Calcium stearate treatment amount: 0.15 kg / h
Airflow and granular material flow velocity: 24 m / sec

[Introducing pipe 5, cylindrical pipe 6, taper 7, outlet 8]
The introduction pipe 5, the cylindrical pipe 6, the taper 7, and the discharge port 8 will be described.
Introduction pipe 5 length: 5m
Introduction pipe 5 nominal diameter: 50A
Cylindrical tube 6 length: 150 mm
Cylindrical tube 6 nominal diameter: 100A
Taper 7 angle: 60 °
Discharge pipe 8 length: 10m
Inlet tube 5, cylindrical tube 6, taper 7, discharge tube 8 Material: Tuftride treatment on the inner surface of SUS304

[Evaluation methods]
Describe the evaluation method.
(1) 100 g of nylon resin pellets and calcium stearate obtained from the discharge pipe 8 are randomly sampled and placed in an Erlenmeyer flask with a stopper.
(2) Put 100 cc of methanol into a conical stoppered flask containing a sample and shake it 20 times up and down.
(3) Put only methanol into the eggplant flask.
(4) Repeat steps (2) and (3) until the cloudiness disappears when methanol is added.
(5) Concentrate the methanol charged into the eggplant flask.
(6) Put concentrated methanol into a platinum crucible and heat to dryness.
(7) The weight of calcium stearate dried in the crucible is measured. Then, the ratio with respect to the weight (= 0.03g) when it was able to mix uniformly ideally is evaluated.

  For example, when the weight of calcium stearate dried in the crucible is 0.02 g, the ratio is 67%.

[Example 1]
Using the airflow mixing apparatus described in FIGS. 1 to 3, the nylon resin pellets and calcium stearate were mixed and sampled under the above conditions and the following procedure.
(1) The airflow generator 2 generates an airflow.
(2) Nylon resin pellets and calcium stearate are charged into the hopper 4 using the granular material supply devices 3a and 3b shown in FIG.
(3) Confirm that the weight of the granular material discharged from the discharge pipe 8 for a certain period of time is equivalent to the weight of the granular material charged in the operation of (2) (within ± 0.1%). .
(4) Sampling 100g of the granular material discharged from the discharge pipe 8.
(5) Sampling is performed 5 times every 10 minutes from the first sampling.

[Comparative Example 1]
Mixing and transportation were performed in the same manner as in Example 1 except that the introduction tube and the discharge tube were directly connected without installing the cylindrical tube 6 and the taper 7. The results are shown in Table 1.

  From the results in Table 1, it can be seen that the variation in Example 1 is smaller than that in Comparative Example 1, and the mixture is uniformly mixed.

  According to the present invention, it is suitable for mixing powder materials such as plastic materials, medical drugs, and processed food materials, but it can also be applied to mixing pigments. However, the application range is not limited to these.

It is a schematic explanatory drawing which shows the structure of embodiment of the airflow mixing apparatus of the granular material of this invention. FIG. 3 is a view of a part of an introduction pipe and a part of a cylindrical pipe, a taper, and a discharge pipe of the airflow mixing device for a granular material of the present invention, and is an explanatory view in a direction perpendicular to the axial direction of the cylindrical pipe. It is a figure of a part of introduction pipe, a cylindrical pipe, a taper, and a discharge pipe of an airflow mixing device of a granular material of the present invention, and is an explanatory view of a horizontal direction to an axial direction of a cylindrical pipe. It is explanatory drawing which shows an example of the Example of the airflow mixing apparatus of the granular material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airflow mixing apparatus of granular material 2 Airflow generator 3a, 3b Powder supply apparatus 4 Hopper 5 Introducing pipe 6 Cylindrical pipe 7 Tapered part 8 Discharge pipe

Claims (8)

Airflow mixing comprising an introduction tube for supplying an airflow containing powder particles present at a predetermined weight ratio, and a cylindrical tube having one end sealed and the other end serving as an air discharge outlet containing the powder particles The cylindrical tube is provided with the introduction pipe in the circumferential tangential direction and has a larger diameter than the introduction pipe, and the air-flow mixing of the granular material is characterized in that apparatus. The airflow mixing device for a granular material according to claim 1, wherein the diameter of the cylindrical tube is 2D to 4D, where D is the diameter of the introduction tube. The airflow mixing device for a granular material according to claim 1 or 2, wherein the discharge port of the cylindrical tube includes a tapered portion for connection to a discharge tube having a smaller diameter than the discharge port. The powder according to any one of claims 1 to 3, wherein when the diameter of the introduction pipe is D, the axial length of the cylindrical pipe toward the discharge port is 2D to 3D from the introduction pipe wall. Granular airflow mixing device. The air flow mixing device for a granular material according to any one of claims 1 to 4, wherein the introduction tube includes a hopper for supplying the granular material. The gas mixing device for a granular material according to any one of claims 1 to 5, wherein the gas for mixing and transporting the granular material is at least one selected from dehumidified air, inert gas, and air. An airflow mixing method for a granular material using the airflow mixing device for a granular material according to any one of claims 1 to 6. The method of mixing air particles according to claim 7, wherein the particles are thermoplastic resin pellets and fatty acid metal salts.

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