JP2016036764A - Pneumatic pulverization device and low temperature pulverization method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic pulverization device and a low temperature pulverization method using the same capable of performing pulverization to a prescribed particle size without causing the thermal denaturation of a grain such as a soybean.SOLUTION: A pneumatic pulverization device includes: a pneumatic pulverizer having two rotary vanes 15, 16 rotating at a high speed and being disposed at the inside of a casing 9 consisting of a cylindrical body 7 and a tapered front lid 8; a raw material supplier continuously supplying a raw material from the back side of the cylindrical body; and a suction unit sucking pulverized matter from the front part of the tapered front lid. A cooling means, for example a cooling jacket circulated with a cooling liquid, capable of suppressing pulverization temperature to 55°C or lower is disposed in the casing.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an airflow crushing facility suitable for crushing soybeans and other cereals and a low-temperature crushing method using the same.

  For example, to produce soy milk for beverages from soybeans, soybeans are pulverized and put into warm water to elute nutrients such as soybean protein. In order to eliminate the powdery and rough feeling from the soy milk beverage, it is necessary to pulverize soybeans to a predetermined particle size or less.

  Conventionally, pin mills, hammer mills, axial flow mills and the like have been generally used for grinding soybeans and other grains. However, with these pulverizers, it has been difficult to obtain a pulverized product having a sharp particle size distribution with little coarse powder. Moreover, it has been almost impossible to finely pulverize raw materials containing a large amount of lipids such as raw soybeans with these pulverizers.

  As an apparatus for refining particles, an airflow crusher such as a jet mill using high-pressure compressed air or steam has been developed (for example, Patent Document 1). In jet mills, particles are made fine by colliding particles using high-pressure air or steam. Such an air pulverizer is utilized for miniaturization of pharmaceuticals and toners. However, since a large amount of high-pressure air or the like is required, facilities such as a large-sized high-pressure compressor are required, and the grinding cost is relatively high because the grinding ability is small. Therefore, it is suitable for pulverizing expensive products such as pharmaceuticals, but is not suitable for pulverizing general food materials.

  Therefore, an airflow crusher (for example, Patent Document 2) in which two high-speed rotating blades are provided inside a casing has been developed as a crusher suitable for crushing food materials. The airflow pulverizer having this structure generates a strong centrifugal airflow between two rotor blades, and pulverizes the pulverized material by vigorously colliding with the airflow. The pulverized material is sucked out from the front end of the casing. It is like that.

  However, in order to eliminate the rough feeling of soy milk, to pulverize soybeans to an average particle size of 20 to 40 μm, 100 μm and 95% pass (95% passes through a sieve with an opening of 100 μm), the rotational speed of the rotary blade is increased. It is necessary to make the particles collide fairly intensely. For this reason, frictional heat due to collision is generated, and it is inevitable that the grinding temperature rises. In particular, when trying to make a fine powder of cereals such as soybeans, lipid oozes due to temperature rise, making it difficult to grind, lowering protein solubility, increasing viscosity and being powdery There was a problem such as becoming a flavor.

  Since raw soybeans contain moisture in addition to lipids, the moisture evaporates during pulverization, and the inside of the casing is cooled by latent heat of evaporation. However, since the latent heat of evaporation varies greatly depending on the moisture content of soybeans and the temperature and humidity during grinding, it has been difficult to stabilize the quality of the ground product.

  In addition, soy beans and the like have different components depending on the varieties, and even in the same variety, there are variations in grain size and contained components. In particular, since dispersion of lipids and sugars greatly affects the crushing conditions, it was very difficult to finely pulverize so as to obtain a stable particle size distribution.

JP-A-1-124361 JP 2011-206621 A

  Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and to provide an airflow grinding facility capable of finely grinding a grain such as soybean to a predetermined particle size without causing heat denaturation, and a low-temperature grinding method using the same. Is to provide.

  The airflow crushing equipment according to claim 1, which has been made to solve the above-mentioned problems, includes an airflow crusher provided with two rotating blades rotating at high speed inside a casing formed of a cylindrical main body and a tapered front lid. An airflow crushing facility comprising a raw material feeder that continuously feeds the raw material from the back side of the cylindrical main body, and a suction duct that sucks and collects the crushed material from the front part of the tapered front lid, wherein the casing is And a cooling means capable of suppressing the pulverization temperature to 55 ° C. or lower. As in claim 2, the cooling means can be a cooling jacket for circulating the coolant.

  Further, a low temperature pulverization method according to claim 3, which has been made to solve the above problems, uses the airflow pulverization equipment according to claim 1 or 2, and uses the current value of the power motor of the airflow pulverizer as a parameter. The pulverization is performed while the supply amount is feedback-controlled.

  According to a fourth aspect of the present invention, there is provided a low-temperature pulverization method using the airflow pulverization equipment according to the first or second aspect, wherein the pulverization is performed while feedback control of the supply amount of the raw material feeder using the internal temperature of the casing as a parameter. It is. A low-temperature pulverization method according to a fifth aspect is characterized by using the airflow pulverization equipment according to the first or second aspect and pulverizing while supplying cold air or dehumidified air together with the raw material. In addition, as described in claim 6, it is preferable to perform feedback control so that the suction air volume of the suction duct is constant.

  Since the airflow pulverization equipment of the present invention is provided with a cooling means that can suppress the pulverization temperature to 55 ° C. or less in the casing, it is possible to finely pulverize grains such as soybeans to a predetermined particle size without causing thermal denaturation. In particular, as in the second aspect, the heat denaturation can be effectively suppressed by using a cooling jacket for circulating the cooling liquid as the cooling means and circulating the cooling water or the antifreezing liquid at 10 ° C. or less, for example.

  The low-temperature pulverization method of the present invention uses an airflow pulverizer in which a cooling means capable of suppressing the pulverization temperature to 55 ° C. or less is provided in the casing, and uses the current value of the power motor of the airflow pulverizer as a parameter or the internal temperature of the casing. As a parameter, the feed amount of the raw material feeder is feedback controlled. With this control, the amount of frictional heat generated during pulverization can be suppressed, heat denaturation can be suppressed more effectively, and pulverization efficiency can be improved by supplying an optimal amount of raw material.

  Further, as in claim 5, by performing pulverization while supplying cold air or dehumidified air together with the raw material, the raw material can be pulverized at a low temperature without being affected by the outside air temperature. In either case, the pulverization particle size can be made constant by performing feedback control so that the suction air volume of the suction duct is constant.

1 is an overall view showing a first embodiment of the present invention. It is a horizontal sectional view of an airflow crusher. It is a general view which shows the 2nd Embodiment of this invention. It is a general view which shows the 3rd Embodiment of this invention.

Embodiments of the present invention will be described below.
FIG. 1 is an explanatory diagram of an embodiment of the present invention, wherein 1 is a raw material hopper, 2 is a raw material supply machine, 3 is an airflow crusher, 4 is a suction duct, and 5 is a pulverized material collection hopper. In addition, although the raw material used by each embodiment is a soybean, other cereals, such as a red bean and rice, may be sufficient.

  The soybean as a raw material is fed from a raw material hopper 1 into a raw material supply machine 2 installed below the raw material hopper 1 and further supplied to an airflow crusher 3. The raw material supply machine 2 is a vibration type quantitative supply device, and the raw material supply amount is controlled by a control device 6 as described later.

  FIG. 2 shows details of the airflow crusher 3. The airflow crusher 3 includes a casing 9 including a cylindrical main body 7 and a tapered front lid 8. A rotating shaft 10 having a cantilever structure is provided inside the casing 9, and a pulley 11 is fixed to an end portion of the rotating shaft 10. A power motor 12 drives the rotating shaft 10 by winding a belt 14 between a driving pulley 13 and a pulley 11 fixed to the output shaft.

  Two rotary blades are attached to the rotary shaft 10. The first rotary blade 15 is disposed inside the cylindrical main body 7 of the casing 9, and the second rotary blade 16 is disposed inside the tapered front lid 8 of the casing 9. As shown in FIG. 2, the end of the cylindrical body 7 is a tapered portion 17 in the opposite direction of the tapered front lid 8, and the tip surface of the first rotary blade 15 is inclined at the same angle as the tapered portion 17. It is considered as a surface. Similarly, the tip surface of the second rotor blade 16 is inclined with the same angle as the tapered portion 18 of the tapered front lid 8. Each of the rotary blades 15 and 16 is a divided blade whose tip side is divided in the circumferential direction, and the number of divided blades is preferably 3-8.

  A raw material supply port 19 is formed in the side wall of the cylindrical main body 7, and the raw material is supplied into the casing 9 from a small hopper 20 disposed on the outlet side of the raw material supply machine 2. The raw material is coarsely pulverized by the first rotary blade 15 rotating at a high speed of 3000 to 8000 rpm, and enters the space 21 sandwiched between the first rotary blade 15 and the second rotary blade 16. A strong centrifugal airflow is formed in the space 21, and the coarsely pulverized particles collide violently with each other and the airflow pulverization is performed. As a result, the particles become fine powder and move into the tapered front lid 8 from the gap between the second rotary blade 16 and the tapered front lid 8. As shown in FIG. 1, a suction duct 4 is connected to the tip of the tapered front lid 8, and fine powder is sucked through the suction duct 4 and collected in the pulverized material collection hopper 5.

  In the airflow crusher 3 of this embodiment, the tapered front lid 8 can be opened and closed around the hinge 22. A lock screw 23 is provided on the opposite side of the hinge 22 so that the tapered front lid 8 can be fixed in a closed state. The tapered front lid 8 is connected to the cylindrical main body 7 via a slide pin 24 and can move a small distance in the axial direction. The hinge 22 is also slidable in the axial direction. For this reason, by interposing the spacer 25 between the tapered front lid 8 and the cylindrical main body 7, the fixing position of the tapered front lid 8 can be moved slightly in the axial direction with respect to the cylindrical main body 7. . As a result, it is possible to adjust the classification performance by changing the gap between the second rotor blade 16 and the inner peripheral surface of the tapered front lid 8.

  The structure of the airflow crusher 3 described above is basically the same as that disclosed in Patent Document 2. However, in the present invention, in order to perform low temperature pulverization, the following devices are added.

  First, the casing 9 is provided with a cooling means that can suppress the pulverization temperature to 55 ° C. or lower. That is, a cooling jacket 26 is formed on the outer peripheral portion of the cylindrical main body 7, and a cooling jacket 27 is also formed on the outer peripheral portion of the tapered front lid 8. A coolant is circulated in the cooling jackets 26 and 27, respectively. As the cooling liquid, water of 10 ° C. or lower can be used. However, when the temperature of the cooling liquid is desired to be 0 ° C. or lower, an antifreeze liquid is used. By setting it as such a structure, the grinding | pulverization temperature in the casing 9 is maintained at 55 degrees C or less. When this temperature exceeds 55 ° C., heat denaturation of soybean is started, which is not preferable. The internal temperature of the casing 9 is measured by the temperature sensor 30 and feedback control is performed on the circulating amount of the coolant.

  In addition, since the heat removal by the cooling jackets 26 and 27 is performed through the wall surface of the casing 9, the heat conductivity and heat transfer coefficient of the wall surface influence the cooling effect. For this reason, the casing 9 in the vicinity of the cooling jackets 26 and 27 can be formed of a metal having a high thermal conductivity. Further, in order to avoid the formation of a heat insulating layer due to the pulverized fine powder adhering to the inner surface of the casing 9, the adhering matter can be removed by periodically applying vibration, air jet or the like. Further, it is preferable that the operation is stopped when the operation is performed for a predetermined time, the tapered front lid 8 is opened, and the deposit on the inner surface is scraped off with a scissors or the like.

  In the first embodiment shown in FIG. 1, the current value of the power motor 12 of the airflow crusher 3 is taken out from the control panel 28, and the control device 6 feedback-controls the supply amount of the raw material feeder 2 using this current value as a parameter. doing. That is, fluctuations in the raw material components, moisture content, pulverization temperature, and the like become pulverization load fluctuations, and these load fluctuations appear as fluctuations in the current value of the power motor 12. For this reason, not only the pulverization temperature in the casing 9 is maintained at 55 ° C. or lower as described above, but also the control is performed to reduce the pulverization load by decreasing the supply amount of the raw material supplier 2 when the current value increases. Thus, stable low-temperature pulverization becomes possible.

  In the second embodiment shown in FIG. 3, the feed amount of the raw material feeder 2 is feedback-controlled using the internal temperature of the casing 9 measured by the temperature sensor 30 as a parameter. That is, when the internal temperature of the casing 9 measured by the temperature sensor 30 exceeds the set value, not only the circulation amount of the coolant is feedback-controlled, but also the supply amount of the material supply machine 2 is feedback-controlled. The supply amount is set to an optimum amount. This second embodiment can be implemented in combination with the first embodiment.

  In 3rd Embodiment shown in FIG. 4, it grind | pulverizes, supplying cold air or dehumidified air to the airflow grinder 3 with a raw material. In FIG. 4, cold air or dehumidified air supplied from the cold air generator 29 is supplied to the raw material hopper 1 and the raw material supply machine 2, but may be supplied from a small hopper 20 disposed on the outlet side of the raw material supply machine 2. it can. This enables grinding in a low temperature atmosphere. This third embodiment can also be implemented in combination with the first embodiment or the second embodiment. As the cold air, it is preferable to use air having a temperature of 10 ° C. or more lower than the temperature in the room where the airflow crusher 3 is installed. It is also possible to use dehumidified air instead of cold air. If the dehumidified air is supplied to the inside of the casing 9, the cooling effect by the latent heat of vaporization can be stabilized.

  The classification performance of the airflow crusher 3 depends on the suction conditions of the suction duct 4. Therefore, in any embodiment, as shown in FIG. 4, an air flow meter or an air pressure meter 32 is arranged in front of the suction blower 31 connected to the pulverized material collection hopper 5 to detect a change in the air flow. The suction blower 31 is preferably feedback-controlled by the controller 33 so that the suction air volume is constant. In FIG. 4, a bag filter 34 is installed inside the pulverized material collection hopper 5, and an air flow meter or an air pressure meter 32 is arranged inside a duct 35 connecting the upper chamber and the suction blower 31. With such an arrangement, the pulverized fine powder can be collected in the lower container 36 without the fine powder adhering to the air flow meter or the duct 35.

  According to the airflow crushing equipment of the present invention described above and the low-temperature crushing method using the same, a grain such as soybean can be finely pulverized to a predetermined particle size without causing thermal denaturation. Specifically, for example, raw soybean can be efficiently pulverized so that the ratio of median diameter is 20 to 40 μm and the particle diameter is 100 μm or less is 95% or more.

DESCRIPTION OF SYMBOLS 1 Raw material hopper 2 Raw material supply machine 3 Airflow crusher 4 Suction duct 5 Ground material collection | recovery hopper 6 Control apparatus 7 Cylindrical main body 8 Tapered front lid 9 Casing 10 Rotating shaft 11 Pulley 12 Power motor 13 Drive pulley 14 Belt 15 1st Rotary blade 16 Second rotary blade 17 Tapered portion 18 Tapered portion 19 Raw material supply port 20 Small hopper 21 Space 22 Hinge 23 Lock screw 24 Slide pin 25 Spacer 26 Cooling jacket 27 Cooling jacket 28 Control panel 29 Cold air generator 30 Temperature sensor 31 Suction blower 32 Air flow meter or air pressure meter 33 Air flow controller 34 Bag filter 35 Duct 36 Container

Claims (6)

An airflow crusher provided with two rotating blades rotating at high speed inside a casing composed of a cylindrical main body and a tapered front lid, and a raw material supply machine for continuously supplying raw materials from the back side of the cylindrical main body , An airflow crushing equipment comprising a suction duct for sucking and collecting the crushed material from the front part of the tapered front lid,
The casing is provided with a cooling means capable of suppressing the pulverization temperature to 55 ° C. or less, and the airflow pulverization equipment is characterized in that   An airflow crushing facility, wherein the cooling means is a cooling jacket for circulating a coolant.   A low-temperature pulverization method using the airflow pulverization equipment according to claim 1 or 2, wherein the pulverization is performed while feedback-controlling the supply amount of the raw material supplier using the current value of the power motor of the airflow pulverizer as a parameter.   A low-temperature pulverization method using the airflow pulverization equipment according to claim 1 or 2, wherein the pulverization is performed while feedback-controlling the supply amount of the raw material supplier using the internal temperature of the casing as a parameter.   A low-temperature pulverization method, wherein the air pulverization equipment according to claim 1 or 2 is used for pulverization while supplying cold air or dehumidified air together with raw materials.   6. The low-temperature pulverization method according to claim 3, wherein feedback control is performed so that the suction air volume of the suction duct is constant.