JP6514656B2 - Pulverizer with classification function - Google Patents

Description

  The present invention relates to a pulverizing apparatus with a classification function, which pulverizes resin, minerals and the like in a pulverizing unit attached to the circumference of a pulverizing rotor that rotates in a pulverizing chamber.

  2. Description of the Related Art As a pulverizing apparatus conventionally used, there is one in which an object to be treated is pulverized with a pulverizing rotor inside a cylindrical pulverizing chamber and a liner attached to the circumferential surface of the pulverizing chamber. In addition, there has also been developed a pulverizing apparatus which classifies the pulverized material to be treated and guides the material which has not reached the predetermined particle size to the pulverizing rotor again.

  For example, in the pulverizing apparatus provided with the classification function of Patent Document 1, an object to be treated pulverized by the pulverizing rotor in the lower part of the apparatus passes the outer periphery of the powder processing chamber and is air-fed transported to the classifying section via the bypass path. Ru.

  Further, as in a pulverizing apparatus having a classification function of Patent Document 2, one is known which is configured of a louver blade (classification blade) in which a classification portion is disposed on a circular top plate circumference. In this pulverizing apparatus, the pulverized material to be treated is classified by the swirling flow generated by the classification blade.

JP 2007-209934 A Unexamined-Japanese-Patent No. 2010-094574

  However, in a fixed classifier such as Patent Document 2, when trying to classify in a particle size region coarser than before, it is necessary to slow the airflow velocity (discharge velocity) in the turning direction, in which case the outer diameter of the device It was necessary to increase the size and height of the classification blade. When the outer diameter of the device is increased, there is a problem that the size of the entire device is increased. In addition, when the height of the classification blade is increased, the variation of the airflow velocity in the turning direction becomes large depending on the distance from the top plate, and the classification point (classification particle diameter) becomes different. Therefore, there is a problem that sharp particle size distribution can not be obtained.

  The present invention has been made in view of the above-mentioned point, and the object of the present invention is to provide an object to be treated in a coarse particle size range with a classification function and a sharp particle size distribution without increasing the size of the apparatus. To make it possible to obtain

  In order to achieve the above object, in the present invention, in the classification section, a cylindrical body is provided between the lower guide section of the classification blade and the upper discharge pipe.

Specifically, the pulverizing apparatus with classification function of the first invention is
An outer casing,
An inner casing forming a space at least a part of which is separated from the outer casing;
An input port for inputting an object to be processed communicated with the inner casing;
A grinding chamber provided below the inner casing and provided with a grinding unit for grinding an object to be treated;
An air flow inlet communicating with the grinding chamber;
A blow-up passage formed between the inner casing and the outer casing and passing an object crushed and blown up in the grinding chamber;
A classification portion provided on an upper portion of the inner casing and having a plurality of classification vanes for swirling an air flow including an object to be treated which is carried from the blow-up passage and classifying the object to be treated;
And a discharge pipe for discharging the processing object classified in the classification section;
The above classification section
A cylindrical body disposed radially inward of the classification blade and having a central through hole communicating with the discharge pipe and a lower surface ;
A clearance is provided below the lower surface of the cylindrical body, and a circular guide portion for guiding an air flow to the discharge pipe through the clearance and the central through hole is provided .

  According to the above configuration, the air containing the object to be treated must pass through the narrow gap between the guide portion and the cylindrical body, so the velocity of the air flow toward the center increases, and the height and width of the classification vanes It is possible to classify in the coarse particle size region without changing the. In addition, since the air including the object to be treated is guided to the discharge pipe through the space between the guide portion and the cylindrical body in a state of being sufficiently rectified at the outer periphery of the cylindrical body, the variation of the air flow velocity in the turning direction is small and sharp. Particle size distribution can be obtained.

In the second invention, in the first invention,
The upper surface of the guide portion has a tapered side surface, and the clearance between the side surface and the lower surface of the cylindrical body gradually narrows radially inward.

  According to the above configuration, the speed of the air flow in the central direction can be reliably increased with a simple configuration.

In the third invention, in the first or second invention,
The lower surface of the space having the classification blade is provided below the lower end of the cylindrical body.

According to the above configuration, as in the prior art, the air containing the object to be treated can be prevented from short-passing and reaching the discharge pipe without being rectified.

  As described above, according to the present invention, a cylinder having a central through hole communicating with the discharge pipe between the discharge pipe and a circular guide portion provided at the bottom of the classification portion to guide the air flow to the discharge pipe By providing the body, it is possible to obtain a sharp particle size distribution without increasing the size of the apparatus for the treatment in the coarse particle size range.

It is an I section enlarged sectional view of FIG. It is a figure showing an outline of a grinding system containing a grinding device concerning an embodiment of the present invention. It is sectional drawing which shows a crushing apparatus. It is a top view which expands and shows a cylinder and a classification blade.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

-Configuration of grinding system-
FIG. 2 shows an outline of a grinding system 10 including a grinding device 1 with a classification function according to an embodiment of the present invention. The grinding system 10 includes a feeder 2 for supplying the raw material to the grinding device 1. The raw material as an object to be treated supplied from the supply device 2 is configured to be supplied to the inlet 11 a of the pulverizing device 1 through the supply rotary valve 3. On the other hand, the object to be treated pulverized by the pulverizing apparatus 1 is transported to the bag filter 4 together with the air flow from the exhaust fan 6. The air flow and the crushed product are separated in the bag filter 4 so that the bag filter rotary valve 5 can be operated and taken out. An exhaust fan 6 is connected to the downstream side of the bag filter 4 so that the air in the grinding system 10 is exhausted to the atmosphere. Below the pulverizing apparatus 1, a drive unit 7 is provided.

  As shown in FIG. 3, the pulverizing apparatus 1 has a cylindrical outer casing 1a, and a cylindrical inner casing 1b smaller in diameter than the cylindrical outer casing 1a is coaxially fixed in the outer casing 1a. Below the inner casing 1b, a grinding chamber 11 is likewise coaxially connected. For example, in the tangential direction of the grinding chamber 11, two air flow inlets 11b are formed symmetrically at the central axis. The air flow inlet 11b may be provided at one place, and it is not necessary to form the air flow inlet 11b in the tangential direction.

  At the lower part of the grinding chamber 11, the grinding rotor 12 is adapted to rotate. The grinding rotor 12 is driven by a drive unit 7 provided below the grinding chamber 11. Although not shown in detail, the grinding rotor 12 is configured to be rotated by the power of the grinding electric motor 13 (shown only in FIG. 2). A cylindrical grinding liner 17 is fixed to the inner peripheral surface of the grinding chamber 11, for example. On the other hand, a plurality of crushing parts 18 are attached to the outer periphery of the crushing rotor 12 so that the tip end approaches the crushing liner 17.

  Further, at the upper part of the inner casing 1b, there is disposed a classification portion 16 which plays a role of swirling the air flow from the blow-up passage 1c and dropping an object to be treated which has not reached a predetermined particle size and returning it to the inner casing 1b. There is. Between the classification portion 16 and the grinding chamber 11, an inlet 11a for introducing an object to be treated is provided so as to communicate with the inner casing 1b. The insertion port 11a is formed in the inside of a cylindrical body inserted so as to have an appropriate insertion angle with respect to the outer casing 1a, and is in communication with the inner casing 1b through the outer casing 1a. On the other hand, a discharge pipe 11 c for discharging the object to be processed extends upward from the center of the upper end of the classification portion 16.

  The air flow from the air flow introduction port 11b passes through a predetermined passage and travels to the crushing chamber 11, and while blowing up the object to be treated, a blow-up passage 1c formed between the outer casing 1a and the inner casing 1b that divides the inside thereof. The air is conveyed to the upper classification unit 16 through the above, and the object of the predetermined particle size is discharged out of the apparatus through the discharge pipe 11c. On the other hand, those which have not reached the predetermined particle size fall into the inner casing 1 b and are crushed again in the grinding chamber 11.

  And as a feature of this embodiment, the classification part 16 has a circular guide part 20 which guides the air flow to the discharge pipe 11 c at its bottom part. A cylindrical body 21 having a central through hole 21a communicating with the discharge pipe 11c is provided between the guide portion 20 and the discharge pipe 11c. The radius r1 of the cylindrical body 21 is smaller than the radius r0 of the circle formed by the tips of the plurality of classification blades 22.

  The guide portion 20 is, for example, a truncated cone and has a tapered side surface 20a. For example, between the side surface 20a and the peripheral edge of the central through hole 21a on the lower surface of the cylindrical body 21 gradually inward in the radial direction It has become narrow. The guide portion 20 may have a conical shape with a pointed tip. If it is conical it is difficult for sediment to accumulate. The radius r2 of the guide portion 20 is desirably the same as the radius r1 of the cylindrical body 21, but may be smaller than the radius r1 of the cylindrical body 21. In addition, as shown in FIG. 4, the disk-shaped top plate 21b of the cylindrical body 21 has a magnitude | size which covers the classification blade 22, for example.

-Need to incline the guide part-
Next, the necessity of inclining the tapered side surface 20 a of the guide portion 20 will be described with reference to FIGS. 1, 3 and 4.

First, the classified particle diameter D (m) is obtained as shown in equation (1). Where: μ: viscosity coefficient of fluid (kg / m 2 sec), ss: density of powder (kg / m ³ ), ρ f: density of fluid (kg / m ³ ), Vt: air flow in the rotational direction (particles) Velocity (m / s), Vr: velocity of air flow toward the center (m / s), r: radius (m)

Equation 1

  As in the pulverizing apparatus 1 of the present embodiment, in the case of centripetal rotational flow, the relationship between the velocity distribution (Vt) in the rotational direction and the radius (r) is as shown in equation (2). In this equation (2), the velocity distribution (Vt) in the rotational direction is in a relationship in which the velocity becomes faster toward the center. At this time, in the case of an ideal rotational flow without energy loss, n = 1.

Equation 2

  Assuming that the clearance C at the lower part of the cylindrical body 21 is constant, the classification point (classification particle diameter D) varies depending on the position of the radius r. When more precise classification is required, it is desirable to make the classified particle size constant at any radius r. Therefore, the side surface of the guide portion 20 is tapered at an angle α. The angle α is, for example, α = 17 ° when the outer diameter of the cylindrical body 21 is 250 mm and the minimum clearance C is 10 mm. Further, the difference h ′ in height between the lower surface of the space where the classification blade 22 is located and the lower end of the cylindrical body 21 needs to be larger than zero. As in the prior art, it is for avoiding short paths without being rectified and reaching the discharge pipe 11c.

-Operation of grinding device-
In the grinding system 10 according to the present embodiment, as shown by the outlined arrows in FIG. 3, the object introduced into the feeder 2 is introduced from the feeder 2 into the inlet 11 a at the top of the grinding chamber 11.

  Then, the input material to be processed is lowered in a funnel 1 d attached to the bottom of the inner casing 1 b and dropped onto the grinding rotor 12.

  The material dropped onto the grinding rotor 12 is conveyed to the outer periphery by centrifugal force, and is ground between the grinding portion 18 and the grinding liner 17.

  The crushed material is blown up by the air flow introduced from the bottom of the crushing chamber 11, as shown by thin solid arrows in FIG. 3, and the blow-up passage 1c in the gap between the inner casing 1b and the outer casing 1a. Are introduced into the classification section 16 and classified.

  Specifically, the crushed object to be treated is carried by air flow and enters from the circumferential side of the classification portion 16, and is swirled by the swirling flow by the classification blade 22 inside the classification portion 16. An object to be treated having a large particle size which has not reached the predetermined particle size collides with the inner peripheral surface of the classification blade 22 and falls into the grinding chamber 11 again.

  In the present embodiment, since the cylindrical body 21 is provided, the air including the object to be processed toward the discharge pipe 11 c is between the tapered side surface 20 a of the guide portion 20 and the lower surface of the cylindrical body 21. I need to go through. Since the minimum clearance C between the tapered surface and the lower surface of the cylindrical body 21 is set small, the velocity Vr of the air flow in the central direction becomes faster, and the object to be treated having a larger particle size than the conventional one is the cylindrical body 21. The gas is discharged from the discharge pipe 11c through the central through hole 21a.

  Next, the object to be treated pulverized by the pulverizing apparatus 1 is transported to the bag filter 4 from the exhaust pipe 11 c together with the air flow from the exhaust fan 6. The air flow and the crushed product are separated in the bag filter 4 and the bag filter rotary valve 5 is operated to take out the crushed product.

-Function of classification part-
First, in the conventional classification section without cylindrical body 21, for example, in the case where the classification particle diameter is planned in the range of 7 to 40 μm under the condition of powder density of 1000 kg / m ³ and treatment air volume of 10 m ³ / min, classification, for example It can be planned with a blade height h = 200 mm, a radius r = 200 mm and an inner diameter of the discharge tube 130 mm. At this time, the speed of the air flow in the rotational direction, that is, the speed Vt discharged from the tangential direction needs to be adjusted in the range of 5 to 30 m / s. The adjustment makes it possible to control the classification particle diameter by making the dimension B between the classification vanes variable between 3.5 and 21 mm. However, in order to plan in an even coarser particle size area, it is necessary to slow the discharge speed Vt. In that case, it is necessary to increase the B dimension or to increase the height h of the discharge portion (classification blade). In order to increase the B dimension, the entire crushing apparatus 1 becomes large. In addition, when the h dimension is increased, the variation of the air flow velocity in the turning direction becomes large due to the distance from the top 21b, and a sharp particle size distribution can not be obtained.

  Therefore, as described above, in the present embodiment, since the cylindrical cylindrical body 21 is provided on the inner side in the radial direction of the classification blade 22, the air including the object to be processed is always between the guide portion 20 and the cylindrical body 21. Need to pass through a narrow clearance C of For this reason, the velocity Vr of the air flow in the center direction is increased, and the coarse particle size region can be classified without changing the height h of the classification blade 22 and the gap B between the classification blades 22. When the clearance C between the side surface 20a of the guide portion 20 and the lower surface of the cylindrical body 21 is, for example, 20 mm, it is found that the classification particle diameter can be adjusted in the range of 23 to 137 μm under the same conditions as the conventional classification portion. Furthermore, since it is led to the discharge pipe 11c in a state of being sufficiently rectified around the cylindrical body 21, a sharp particle size distribution can be obtained.

  As described above, according to the present invention, the central portion communicated with the discharge pipe 11c between the circular guide portion 20 provided at the bottom of the classification portion 16 and guiding the air flow to the discharge pipe 11c and the discharge pipe 11c. By providing the cylindrical body 21 having the through holes 21a, it is possible to obtain a sharp particle size distribution without increasing the size of the pulverizing apparatus 1 for the material to be treated in the coarse particle size range.

(Other embodiments)
The present invention may be configured as follows for the above embodiment.

  That is, the method of pulverization is a method (rotational type) having the pulverization rotor 12 in the pulverization chamber 11, and in addition to the method of pulverization, crushing, and grinding between the pulverizing unit 18 and the pulverizing liner 17 It is also possible to adopt a vortex flow type or the like in which the object to be treated is rotated on the swirling flow and collides with the grinding liner 17 without providing the reference numeral 12.

  The above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications and uses.

1 Pulverizer (classifier with classification function)
1a Outer casing
1b inner casing
1c passage
1d funnel
2 Supply machine
3 Rotary valve for supply
4 bug filter
5 Rotary valve for bag filter
6 Exhaust fan
7 Drive
10 grinding system
11 grinding chamber
11a input port
11b Airflow inlet
11c Exhaust pipe
12 grinding rotor
13 Electric motor for grinding
16th class
17 Grinding liner
18 Pulverizing unit
20 Guide section
20a side
21 cylinder
21a central through hole
21b top board
22 classification blades

Claims (2)

An outer casing,
An inner casing forming a space at least a part of which is separated from the outer casing;
An input port for inputting an object to be processed communicated with the inner casing;
A grinding chamber provided below the inner casing and provided with a grinding unit for grinding an object to be treated;
An air flow inlet communicating with the grinding chamber;
A blow-up passage formed between the inner casing and the outer casing and passing an object crushed and blown up in the grinding chamber;
A classification portion provided on an upper portion of the inner casing and having a plurality of classification vanes for swirling an air flow including an object to be treated which is carried from the blow-up passage and classifying the object to be treated;
And a discharge pipe for discharging the processing object classified in the classification section;
The above classification section
A cylindrical body disposed radially inward of the classification blade and having a central through hole communicating with the discharge pipe, and a bottom plate defining the periphery of the central through hole ;
Than the bottom plate of the cylindrical body is provided with a gap downward, and a circular guide portion for inducing air flow into the discharge pipe through the clearance and the central through-hole,
An upper surface of the guide portion has a tapered side surface, and a clearance between the side surface and the bottom plate of the cylindrical body gradually narrows radially inward. . The pulverizing apparatus with classification function according to claim 1
Upper surface of the member to form a space with the classification blade, classifying function with milling apparatus characterized by being provided in the upper side than the lower end of the cylinder.

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