CN116648308A

CN116648308A - Exhaust guide, vertical pulverizer, and exhaust method

Info

Publication number: CN116648308A
Application number: CN202180080727.3A
Authority: CN
Inventors: 安藤文典; 堀田滋; 笠井大辅
Original assignee: Kawasaki Jukogyo KK
Current assignee: Kawasaki Motors Ltd
Priority date: 2020-12-01
Filing date: 2021-11-30
Publication date: 2023-08-25
Also published as: WO2022118863A1; DE112021006244T5; JPWO2022118863A1

Abstract

The exhaust gas guide of the present invention is used in a vertical pulverizer having a separator for classifying powder by a rotor, and discharges gas mixed with the powder. The exhaust guide includes a housing and a core. A gas flow passage is formed inside the housing. The core is disposed inside the housing. An opening for introducing gas from below into the interior of the housing is formed in the housing. The outer peripheral portion of the housing has a curved portion and a straight portion. The straight line portion is connected with the curved line portion in a tangential direction. The center line of the gas flow passage corresponding to the straight portion is offset from the center of the core portion in a plan view. An exhaust port for exhausting gas is formed at a terminal end of the gas flow passage corresponding to the straight portion.

Description

Exhaust guide, vertical pulverizer, and exhaust method

Technical Field

The present disclosure relates to gas venting in a vertical pulverizer.

Background

In a vertical mill for milling a raw material, a structure in which a gas inlet and a gas outlet are formed is known. Patent document 1 discloses such a vertical pulverizer.

In patent document 1, a gas inlet is provided at a lower portion of a vertical mill, and a product outlet is provided at an upper housing of the vertical mill. The raw material pulverized by the pulverizing roller is blown up by the gas introduced from the gas introduction port. The blown-up raw material is classified by a separator having a rotating part. The classified powdery raw material is taken out from the product take-out port together with the gas.

The separator is accommodated in the upper housing. The upper housing covers over the separator. The upper housing includes a base having a center point. In patent document 1, the center point of the base is disposed eccentrically with respect to the rotation center axis of the separator.

In patent document 1, the offset of the theoretical classification point in the circumferential direction of the separator can be eliminated by this eccentric arrangement, so that the particle size width of the particle size distribution of the product can be reduced, and the product quality can be improved.

[ Prior Art literature ]

[ patent literature ]

Patent document 1: japanese patent No. 6497079

Disclosure of Invention

Problems to be solved by the invention

In the vertical pulverizer as in patent document 1, a swirling airflow generated by rotation of a rotor causes a pressure loss when passing through an upper housing disposed above the rotor. This pressure loss causes an increase in power consumption of the blower fan and the like.

In patent document 1, the base of the upper case is disposed eccentrically, but this is to reduce the size width of the classification, and the pressure loss is not considered. Therefore, a structure that is more energy-saving is required.

The present disclosure has been made in view of the above circumstances, and an object thereof is to reduce pressure loss of an air flow and improve energy saving performance in an exhaust guide of a vertical pulverizer.

Solution for solving the problem

As described above, the solution to the problem of the present disclosure and the effects thereof will be described below.

According to a first aspect of the present disclosure, there is provided an exhaust guide of the following structure. That is, the exhaust gas guide is used in a vertical pulverizer having a separator for classifying powder by a rotor, and discharges gas mixed with the powder. The exhaust guide includes a housing and a core. The housing is internally formed with a gas flow passage. The core is disposed inside the housing. An opening for introducing gas from below into the interior of the housing is formed in the housing. The outer peripheral portion of the housing has a curved portion and a straight portion. The straight line portion is connected with the curved line portion in a tangential direction. The center line of the gas flow passage corresponding to the straight portion is offset from the center of the core portion in a plan view. An exhaust port for exhausting gas is formed at a terminal end of the gas flow passage corresponding to the straight portion.

According to a second aspect of the present disclosure, there is provided an exhaust method for exhausting gas mixed with powder in a vertical pulverizer having a separator classifying the powder by a rotor. The vertical crusher includes a housing and a core. The housing is internally formed with a gas flow passage. The core is disposed inside the housing. An opening for introducing gas from below into the interior of the housing is formed in the housing. The outer peripheral portion of the housing has a curved portion and a straight portion. The straight line portion is connected with the curved line portion in a tangential direction. The center line of the gas flow passage corresponding to the straight portion is offset from the center of the core portion in a plan view. The exhaust method includes a first process, a second process, and a third process. In the first step, a gas is introduced into the interior of the case from the opening. In the second step, the gas inside the case is caused to flow in the order of the curved portion and the straight portion. In the third step, the gas flowing along the straight portion is discharged from the gas outlet.

In this way, the introduced gas rises while swirling, and is discharged from the exhaust port so as not to interfere with the swirling, so that variation in the velocity of the gas flow in the vicinity of the exhaust port can be suppressed. As a result, the pressure loss of the exhaust guide can be effectively reduced, and energy saving can be achieved. Further, since turbulence of the air flow can be reduced in the exhaust guide, abrasion of the inner wall can be suppressed, and durability is excellent.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, in the exhaust guide of the vertical pulverizer, the pressure loss of the air flow can be reduced, and the energy saving performance can be improved.

Drawings

Fig. 1 is a perspective view showing the overall structure of a vertical crusher according to an embodiment of the present disclosure.

Fig. 2 is a perspective view of the exhaust guide as viewed from above.

Fig. 3 is a top view of the exhaust guide.

Fig. 4 is a perspective view of the exhaust guide as seen from below.

Fig. 5 is a diagram illustrating a flow velocity distribution of an air flow at an exhaust port in an exhaust guide of a comparative example.

Fig. 6 is a diagram illustrating a flow velocity distribution of the air flow at the exhaust port in the exhaust guide of the present embodiment.

Detailed Description

Embodiments of the present disclosure are described below with reference to the drawings. Fig. 1 is a perspective view showing the overall structure of a vertical crusher 1 according to an embodiment of the present disclosure. Fig. 2 is a perspective view of the exhaust guide 16 as viewed from above. Fig. 3 is a top view of the exhaust guide 16. Fig. 4 is a perspective view of the exhaust guide 16 as seen from below.

The vertical crusher 1 shown in fig. 1 can crush an input object. Examples of the object to be pulverized include cement, slag, coal, and the like, but are not limited thereto.

The vertical crusher 1 includes a speed reducer 2, a lower casing 3, an upper casing 4, a rotary table 5, crushing rollers 6, a hydraulic cylinder 9, a coarse powder return guide 11, a charging chute 12, a separator 15, and an exhaust guide 16. In order to easily understand the structure and the like inside the vertical crusher 1, a part of the structure is shown in a chain line in a three-dimensional manner in fig. 1.

A rotary table 5 is mounted on the upper portion of the speed reducer 2. The turntable 5 is supported rotatably about a rotation axis in the up-down direction.

A motor 60 as a drive source is disposed near the speed reducer 2. The rotation of the output shaft of the motor 60 is transmitted to the speed reducer 2 via the transmission shaft 61. The speed reducer 2 reduces the rotation input from the motor 60, and transmits the rotation to the turntable 5.

The rotary table 5 is formed in a circular shape in a plan view. The rotary table 5 can receive the objects to be crushed, which are put into the vertical crusher 1, on the upper surface. The pulverizing rollers 6 are disposed so as to be placed on the peripheral portion of the upper surface of the rotary table 5. The number of the pulverizing rollers 6 is arbitrary. The lower casing 3 is disposed so as to surround the turntable 5 and the space above it. A plurality of pulverizing rollers 6 are located in the inner space of the lower housing 3.

Around the speed reducer 2 (outside the lower case 3), a bracket 7 is provided so as to correspond in position to each pulverizing roller 6. A pressing arm 8 is rotatably supported by the holder 7, and the pressing arm 8 is configured to press the grinding roller 6 against the rotary table 5.

The pressing arm 8 is formed to be elongated in the up-down direction. The pressing arm 8 is supported by the bracket 7 at its longitudinal middle portion so as to be rotatable about a horizontal axis. The lower end of the pressure arm 8 is connected to a hydraulic cylinder 9. The upper end of the pressing arm 8 is connected to a support member 10 described later.

The support member 10 is a cylindrical member, and its axis is arranged along the radial direction of the turntable 5 in a plan view. The support member 10 is rotatably supported by the bracket 7. The front end portion of the support member 10 is inserted into the inside of the lower case 3. The pulverizing roller 6 is supported in a cantilever shape at the front end portion of the supporting member 10.

One end of the hydraulic cylinder 9 is connected to the ground, and the other end is connected to the pressurizing arm 8. When driven in the direction of the contraction hydraulic cylinder 9, the pressing arm 8 and the support member 10 can apply a force in the direction of bringing the grinding roller 6 closer to the turntable 5.

A funnel-shaped coarse powder return guide 11 is disposed above the rotary table 5. The lower part of the coarse powder return guide 11 is formed in a small diameter cylindrical shape. A downward opening is formed in the lower end portion of the coarse powder return guide 11, and the downward opening is opposed to the upper surface center portion of the turntable 5.

A cylindrical input chute 12 is connected to the middle of the lower part of the coarse powder return guide 11. The input chute 12 is disposed so as to extend through the upper case 4. An inlet 13 is formed at an end of the inlet chute 12 outside the upper case 4.

The upper portion of the coarse powder return guide 11 is formed in a hollow cone shape having a diameter that increases as it goes upward. The upper end of the coarse powder return guide 11 is opened upward.

A separator 15 is disposed at an upper portion of the vertical crusher 1. The separator 15 includes fixed blades 14 and a rotor 31.

The fixed blades 14 are provided in plurality above the outer peripheral portion in the opening formed in the upper end of the coarse powder return guide 11. The plurality of stationary blades 14 are arranged in a circumferential direction at appropriate intervals so as to substantially follow the outer periphery of the opening of the coarse powder return guide 11. Each of the fixed blades 14 is formed elongated in the up-down direction.

The rotor 31 is disposed inside the upper case 4 and suspended and supported above the coarse powder return guide 11. The rotor 31 is rotatable about a rotation axis in the up-down direction. The rotor 31 includes a plurality of rotating blades 33. The plurality of rotary blades 33 are arranged in a circumferential direction at appropriate intervals. Each of the rotary blades 33 is formed to be elongated in the up-down direction. The rotating blades 33 are located immediately on the inner peripheral side of the fixed blades 14.

The central shaft 34 of the rotor 31 is fixed to a transmission shaft 35 for transmitting rotational force to the rotor 31. The drive shaft 35 is coupled to a suitable drive source (not shown). Thereby, the rotor 31 can be rotated in the thick arrow direction of fig. 1.

An annular frame 36 is disposed on the outer peripheral side of the upper portion of the center shaft 34. The ring frame 36 is fixed to the central shaft 34 by a plurality of rod-like members 37. Each rod-like member 37 is formed elongated in the radial direction. The plurality of rod-like members 37 are arranged in a circumferential direction at appropriate intervals. The upper end of each rotary vane 33 is fixed to the annular frame 36.

A bottom plate 38 is fixed to a lower portion of the center shaft 34. The bottom plate 38 is formed in a tapered shape having a diameter that increases as it decreases. The lower end of each rotary blade 33 is fixed to the outer peripheral portion of the bottom plate 38.

The space between the central shaft 34 and the rotating blades 33 is open at the upper side and closed at the lower side by a bottom plate 38. The inner space of the rotor 31 is connected to the inner space of the exhaust guide 16 disposed above the rotor 31.

A hollow exhaust guide 16 is fixed above the upper case 4. The internal space of the exhaust guide 16 is opened downward. The open portion is connected to the inside of the upper case 4. An exhaust port 41 directed obliquely upward is formed in the exhaust guide 16. The structure of the exhaust guide 16 will be described later in detail.

An inlet 71 for introducing gas (hot air) into the lower case 3 is formed in the lower portion of the lower case 3.

Next, the operation of the vertical crusher 1 according to the present embodiment will be described by way of example in the case where the vertical crusher is applied to a fine grinding process of cement manufacturing equipment.

When the vertical crusher 1 starts to operate, the rotary table 5 and the rotor 31 rotate. In this state, a mixture of clinker, which is an intermediate product of cement, and a secondary raw material such as gypsum is fed into the inlet 13 of the vertical crusher 1.

The clinker and the secondary raw material to be charged drop from the lower end of the coarse powder return guide 11 to the center of the rotary table 5 via the charging chute 12 and the coarse powder return guide 11. The clinker and the secondary raw material are rotated together with the rotary table 5, and moved to the outer peripheral side by centrifugal force. As a result, the clinker and the secondary raw material are crushed by the crushing roller 6 located on the outer peripheral side of the rotary table 5.

The pulverized and pulverized clinker and the powder of the secondary raw material (hereinafter simply referred to as powder) are blown up by the gas supplied from the inlet 71. The powder is guided to the outer peripheral side of the fixed blades 14 by the cone-shaped portion of the upper part of the coarse powder return guide 11, and then passes between the fixed blades 14 from the outer periphery to the inner periphery together with the gas. The powder can pass through the rotating blades 33 which rotate as long as it is sufficiently fine. The powder passing through the gaps of the rotating blades 33 is discharged upward from the space on the inner peripheral side of the rotating blades 33, and is supplied into the exhaust guide 16. The powder-mixed gas supplied to the exhaust guide 16 is discharged from the exhaust port 41.

In the case where the powder cannot pass through the gap of the rotating blade 33 due to being large, the powder falls down due to its own weight toward the upward opening formed on the coarse powder return guide 11. The coarse powder falls down again from the lower end of the coarse powder return guide 11 to the upper surface center portion of the rotary table 5, and is crushed again by the crushing roller 6.

A bag filter, not shown, and a suction fan are connected to the exhaust port 41. The clinker and the auxiliary raw material powder are collected by a bag filter and delivered as finished cement. Instead of the suction fan, a propulsion fan may be provided upstream of the inlet 71.

The plurality of stationary blades 14 are each oriented in an inclined manner with respect to the circumferential direction. In addition, the rotating blades 33 move along a circular path on the inner circumferential side of the fixed blades 14 in close proximity with the rotation of the rotor 31. Thus, a swirling flow component swirling in the direction of the thick arrow in fig. 1 is imparted to the gas passing through the fixed vane 14 and the rotating vane 33 in this order. Thus, the powder-mixed gas flows spirally from the inside of the rotor 31 to the inside of the exhaust gas guide 16.

The exhaust guide 16 has such a characteristic shape in order to smoothly discharge the gas having the swirling component from the exhaust port 41. Next, the exhaust guide 16 will be described in detail mainly with reference to fig. 2 to 4.

The exhaust guide 16 includes a hollow housing 42. An annular opening 43 is formed below the housing 42. Through this opening 43, the gas mixed with the powder flows from the separator 15 on the lower side into the interior of the housing 42.

A cylindrical portion (core portion) 44 is fixed to a substantially central portion of the housing 42. The cylindrical portion 44 defines the inner peripheral side of the swirl-shaped gas flow passage in the case 42.

The cylindrical portion 44 is disposed with its axis directed in the up-down direction. The center of the cylindrical portion 44 coincides with the center of the annular opening 43. The upper and lower sides of the cylindrical portion 44 are open. Although the drive shaft 35 is omitted from fig. 2 later, the drive shaft 35 passes through the inside of the cylindrical portion 44. The central axis of the cylindrical portion 44 coincides with the rotation axis of the rotor 31 in the separator 15.

As shown in fig. 2, the outer periphery of the housing 42 has a first portion 45a having a constant diameter, a second portion (curved portion) 45b having a diameter that increases in the circumferential direction as approaching the exhaust port 41, and a linear third portion (linear portion) 45c connected to the terminal end of the second portion 45b.

The first portion 45a corresponds to an upstream portion of the gas flow passage in the exhaust guide 16. Since the diameter of the housing 42 is constant in the first portion 45a, the distance between the cylindrical portion 44 and the side wall of the outer peripheral portion of the housing 42 is substantially constant. In the first portion 45a, the outline of the outer peripheral portion of the opening 43 in plan view substantially coincides with the outline of the outer peripheral portion of the housing 42.

In a region corresponding to the first portion 45a, a screw guide (guide portion) 46 is fixed between the cylindrical portion 44 and the housing 42. The spiral guide 46 is formed in a spiral shape so as to be upward with a phase change, and the phase changes so as to be close to the downstream side of the gas flow passage in the exhaust guide 16. The upper end of the screw guide 46 is connected to the underside of the upper wall of the housing 42. The spiral guide 46 can guide the gas flowing from the opening 43 into the vicinity of the upstream end of the gas flow path of the exhaust guide 16 to smoothly swirl and flow in the housing 42.

The second portion 45b corresponds to a middle portion of the gas flow passage in the exhaust guide 16. In the second portion 45b, the diameter of the housing 42 increases smoothly as approaching the circumferential side (downstream side of the flow passage). Thus, the second portion 45b is swirling in a plan view.

In the second portion 45b, the distance between the cylindrical portion 44 and the outer peripheral portion of the housing 42 gradually increases as going downstream. As a result, the flow passage cross-sectional area increases as going downstream. The center line of the flow passage in plan view is formed in a spiral shape that changes so as to be separated from the center of the cylindrical portion 44 as going downstream.

The space between the lower end of the second portion 45b of the housing 42 and the edge portion of the opening 43 is closed by a closing plate 47. The center of the annular opening 43 coincides with the center of the cylindrical portion 44. By closing between the portion protruding to the outer peripheral side in the case 42 (the second portion 45 b) and the edge portion of the opening 43 using the closing plate 47, leakage of gas from the lower portion of the case 42 can be prevented.

The third portion 45c corresponds to a downstream portion of the gas flow passage in the exhaust guide 16. The third portion 45c is connected to an end of the curved (arc-shaped) second portion 45b in the tangential direction.

The linear flow path corresponding to the third portion 45c is curved so as to incline obliquely upward in the middle of the longitudinal direction. The exhaust port 41 is formed at a terminal end of the downstream portion.

The linear flow passage corresponding to the third portion 45c is formed so that its cross section is rectangular. As shown in fig. 3, the center line 48 of the flow path is offset to one side with respect to the center of the cylindrical portion 44 in a plan view. The partial flow path of the third portion 45c may be formed so that its cross section is circular.

In the above-described structure, the gas is introduced into the case 42 through the opening 43 (first step). Specifically, the gas flows spirally through the opening 43 to the space corresponding to the first portion 45a or the second portion 45b. The gas flows along the second portion 45b, that is, along a portion of a vortex shape in which the diameter of the outer peripheral portion of the housing 42 increases as going downstream. The flow path cross-sectional area is simply increased by the increased diameter, and the swirl is not hindered, so that the deviation of the velocity of the air flow is not easily caused. The gas flows in the order of the second portion 45b and the third portion 45c (second process). The diameter of the second portion 45b is set so that the flow rate does not rise even when the second portion merges with the gas from below as it goes downstream. Since the second portion 45b is connected to the third portion 45c in the tangential direction, turbulence of the air flow hardly occurs at the connection portion. Then, the gas is discharged obliquely upward from the gas outlet 41 (third step).

By using the exhaust guide 16 having such a structure, pressure loss at the time of passage of the air flow can be effectively suppressed. This can realize, for example, energy saving of the blower fan provided on the downstream side of the exhaust guide 16. In addition, since the deviation in the velocity of the air flow (in other words, the disturbance of the air flow) is suppressed, the powder can be prevented from striking the inner wall of the housing 42 with a strong force. As a result, abrasion inside the housing 42 can be reduced.

Fig. 5 and 6 show the results of obtaining flow velocity distributions of the exhaust ports 41 and 41z by a simulation analysis based on numerical fluid mechanics, respectively, for the exhaust guide 16z of the comparative example and the exhaust guide 16 of the present embodiment.

The exhaust guide 16z of the comparative example will be briefly described. In the exhaust guide 16z of the comparative example, the center line of the linear flow path facing the exhaust port 41z is disposed so as not to be offset from the center of the cylindrical portion 44z disposed inside the housing 42 z. The housing 42z does not have a helical second portion 45b as in the illustrated embodiment. The linear flow path toward the exhaust port 41z is connected to the housing 42z in the radial direction, not to the outer periphery of the housing 42z in a tangential manner.

In each of the exhaust ports 41 and 41z, a portion having a flow velocity greater than a predetermined value is indicated by hatching. In the exhaust guide 16z of the comparative example, it is found that the flow velocity is particularly high in the portion (a-B side) on the outer peripheral side in the swirling direction of the gas, in which the flow velocity is increased, in the exhaust port 41z, over a wide range. On the other hand, in the exhaust guide 16 of the present embodiment, it is known that the occurrence of the flow rate increasing portion is effectively suppressed in the exhaust port 41.

As described above, the exhaust guide 16 according to the present embodiment is used in the vertical mill 1 having the separator 15 for classifying the powder by the rotor 31, and exhausts the gas mixed with the powder. The exhaust guide 16 includes a housing 42 and a cylindrical portion 44. A gas flow passage is formed in the housing 42. The cylindrical portion 44 is disposed inside the housing 42. The housing 42 is formed with an opening 43 for introducing gas from below into the interior of the housing 42. The outer peripheral portion of the housing 42 has a curved second portion 45b and a linear third portion 45c. The third portion 45c is connected to the second portion 45b in a tangential direction. The center line 48 of the gas flow passage corresponding to the third portion 45c is offset from the center of the cylindrical portion 44 in plan view. An exhaust port 41 for exhausting gas is formed at a terminal end of the gas flow passage corresponding to the third portion 45c.

In this way, the introduced gas rises while swirling, and is discharged from the exhaust port 41 so as not to interfere with the swirling, so that variation in the velocity of the gas flow in the vicinity of the exhaust port 41 can be suppressed in particular. As a result, the pressure loss in the exhaust guide 16 can be effectively reduced, and energy saving can be achieved. In addition, since uneven wear of the inner wall of the exhaust guide 16 can be suppressed, durability is good.

In the exhaust guide 16 according to the present embodiment, the second portion 45b is formed in a spiral shape so that the distance from the center of the cylindrical portion 44 increases as approaching the third portion 45c in the circumferential direction.

Thus, the swirling flow smoothly flows in the casing 42, and thus the pressure loss can be further reduced.

The exhaust guide 16 of the present embodiment includes a closing plate 47, and the closing plate 47 closes the lower side of the housing 42 between the second portion 45b of the outer peripheral portion of the housing 42 and the edge portion of the opening 43.

Thereby, in the scroll portion of the second portion 45b, the air flow can be prevented from leaking from the lower portion of the housing 42.

The exhaust guide 16 of the present embodiment includes a spiral guide 46. The spiral guide 46 is disposed above at least a part of the swirling gas flow path from the opening 43 to the outlet 41.

Thus, the gas introduced into the case 42 through the opening 43 can be guided so as to smoothly flow along the swirl-shaped gas flow path.

The vertical crusher 1 of the present embodiment includes an exhaust guide 16 and a separator 15. The separator 15 sorts the powder by the rotor 31.

This allows the gas mixed with the classified powder to be smoothly discharged from the gas outlet 41.

The preferred embodiments of the present disclosure have been described above, but the structure may be modified as follows, for example.

The closing plate 47 may be formed in an inclined shape. The direction of the inclination may be arbitrary, and for example, the closing plate 47 may be inclined in a downward manner as approaching the opening 43. Since the closing plate 47 is inclined, powder is less likely to accumulate on the upper surface of the closing plate 47, and thus maintainability is improved.

The second portion 45b may not be formed in a spiral shape, but may be formed in a constant diameter similar to the first portion 45 a.

The first portion 45a may not be formed to have a constant diameter, but may be formed to have a spiral shape similar to the second portion 45b.

Instead of the cylindrical portion 44, a rod-shaped column portion, for example, may be disposed inside the case 42.

The helical guide 46 may also be omitted. The same effect can be exerted by forming the upper wall of the housing 42 in a spiral shape to serve as a guide portion.

The lower end of the input chute 12 may not be connected to the middle portion of the coarse powder return guide 11. In this case, the clinker and the secondary raw material charged into the charging port 13 directly fall from the lower end of the charging chute 12 onto the rotary table 5.

In the above embodiment, the vertical crusher 1 is configured such that the rotation direction of the rotor 31 is the direction of the bold arrow in fig. 1. However, the vertical crusher 1 may be configured such that the rotation direction of the rotor 31 is opposite to the above-described direction.

Claims

1. An exhaust gas guide for use in a vertical pulverizer having a separator for classifying powder by a rotor, the exhaust gas guide discharging gas mixed with the powder, the exhaust gas guide comprising:

a housing having a gas flow passage formed therein; and

a core portion disposed inside the housing,

an opening for introducing gas from below into the interior of the housing is formed in the housing,

the outer peripheral portion of the housing has a curved portion and a straight portion connected to the curved portion in a tangential direction,

the center line of the gas flow passage corresponding to the straight portion is offset from the center of the core portion in a plan view,

an exhaust port for exhausting gas is formed at a terminal end of the gas flow passage corresponding to the straight portion.

2. The exhaust gas guide according to claim 1, wherein,

the curved portion is a scroll-like portion that increases in distance from the center of the core in the circumferential direction as approaching the straight portion.

3. The exhaust gas guide according to claim 2, wherein,

the seal plate seals the lower side of the housing between the scroll portion of the outer peripheral portion of the housing and the edge portion of the opening.

4. The exhaust gas guide according to claim 3, wherein,

the closing plate is inclined.

5. The exhaust guide according to claim 1 or 2, characterized in that,

the gas flow passage has a spiral guide portion disposed above at least a part of the swirl gas flow passage extending from the opening to the exhaust port.

6. A vertical crusher, comprising:

the exhaust guide according to any one of claims 1 to 5; and

the separator classifying the powder by the rotor.

7. A method for exhausting gas mixed with powder in a vertical pulverizer having a separator for classifying the powder by a rotor, characterized in that,

the vertical crusher has:

a housing having a gas flow passage formed therein; and

a core portion disposed inside the housing,

the exhaust method comprises the following steps:

a first step of introducing a gas into the case from the opening;

a second step of flowing the gas inside the case along the curved portion and the straight portion in this order; and

and a third step of discharging the gas flowing along the straight portion from the gas outlet.