JPH1099702A - Liquid jetting device in roller mill and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the self-excited vibration in a roller mill and to stably use the roller mill. SOLUTION: In gaps between adjacent pulverizing rollers 1, 1, air nozzles 12 and water nozzles 16 are installed. In this case, in one gap, either the air nozzle 12 or the water nozzle 16 is installed, or both of them are installed. Water and air are not simultaneously, and according to a state of the coal layer in the pulverizing part of a mill and operating conditions of the mill, the two fluids are properly used and jetted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller mill and, more particularly, to a technique for spraying a fluid onto a raw material powder layer in a pulverizing section to prevent vibration, that is, a fluid ejecting apparatus and method.

[0002]

2. Description of the Related Art In coal-fired boilers, low-pollution combustion (low N
Ox, low-ash unburned components) and wide-area load operation are performed, and accordingly, pulverized coal machines (mills) are also required to have high crushing performance and reliability.

[0003] As one type of mill for finely pulverizing lump such as coal, cement raw material or new raw material, a vertical roller mill which pulverizes with a rotating table and a plurality of tire-type pulverizing rollers has recently been used. It is widely used, especially in Japan.

Here, a general configuration of a roller mill will be described with reference to FIG.

[0005] This type of mill is provided at a lower portion of a cylindrical housing 6 and is driven by a motor and rotates at a low speed through a speed reducer. A plurality of pulverizing rollers 1 are rotated by applying a load by hydraulic pressure or a sprig or the like to a position equally divided in a circumferential direction on an upper surface of the pulverizing roller.

The raw material 4 supplied to the center of the rotary table 2 from the raw material supply pipe (center chute) 5 moves to the outer periphery of the rotary table 2 by drawing a spiral trajectory on the rotary table 2 by centrifugal force and rotates. It is bitten between the pulverizing race of the table 2 and the pulverizing roller 1 and pulverized to form the raw material powder layer 3.

A hot air (primary air) 8 is guided through a duct to a lower portion of the housing 6, and the hot air 8 blows up between a throat vane 9 of an air throat between the rotary table 2 and the housing 6. ing.

The crushed powder is dried while rising inside the housing 6 by hot air 8 blown up from an air throat. The granular material transported above the housing 6 falls from the coarse material by gravity (primary classification), and is pulverized again in the pulverizing unit.

The slightly fine particles passing through the primary classifier are classified again by a fixed classifier (cyclone separator) or a rotary classifier (rotary separator) 7 provided on the upper part of the housing 6. Fine powder smaller than a predetermined particle size is conveyed by an air current and sent to a pulverized coal burner in a boiler.

[0010] The coarse powder having a predetermined particle size or more that has not passed through the classifier falls onto the rotary table 2 by the action of gravity and is pulverized again together with the raw material just supplied into the mill.
In this way, pulverization is repeated in the mill, and product fine powder is generated.

A problem that arises when the roller mill is operated with a low load or when the load is reduced or stopped is the vibration of the mill.

This vibration phenomenon is a kind of friction vibration caused by the sliding of the coal seam and the roller, and the vibration type is self-excited vibration. In the case of constant load operation, this vibration often increases in ordinary coal during low load operation (conditions with little coal hold-up in the mill),
Depending on the type of coal, it can also occur at very high loads.

In a roller mill of a type that supports a crushing roller so as to be capable of pendulum movement, a crushing roller is supported via a roller bracket so as to be capable of pendulum movement with a roller pivot as a support shaft. The function of this pendulum movement is very important. When the crushing roller bites a hardly crushable foreign substance such as an iron piece, the crushing roller can avoid an impact by performing a pendulum movement.

Further, when the crushing roller or the crushing race is worn and deformed, the pendulum motion also has an effect of automatically and centrally finding an appropriate pressing position (the positional relationship between the crushing roller and the crushing race).

Generally, under high load and steady grinding conditions,
The crushing roller has almost no pendulum movement.

As described above, when the grinding roller actively engages when the mill is started or when the load is increased, the grinding roller makes a pendulum motion at a slow speed. Not directly involved in the occurrence of

On the other hand, intense self-excited vibration is likely to occur when the mill is under a reduced load or when the mill is stopped. In the process of rapidly reducing the load in this way, the coal layer in the pulverizing section is small and fine, and the rolling of the pulverizing roller tends to be extremely unstable.

FIG. 13 schematically illustrates a pattern of occurrence when the amount of coal supplied changes in the process from the time of constant high load operation to the stop of the mill.

First, after the start of the load reduction, self-excited vibration is generated in the process of the load reduction as follows. Further, after the coal feeder stops, self-excited vibration occurs. These are intense self-excited vibrations.

On the other hand, when the crushing section of the mill is almost empty,
A forced vibration is generated as shown in FIG. Although this forced vibration does not have a self-amplifying property, it is more desirable that the vibration be suppressed to a low level.

As a conventional countermeasure against vibration, there is a technique (air blow method) of blowing air to a powder layer of a pulverizing section (for example, Japanese Patent Publication No. Hei 6-85880 shown in FIG. 15). This technique suppresses self-excited vibration by the action of flying fine powder in the powder layer or deforming the powder layer by the force of the air flow.

In FIG. 15, reference numeral 1401 denotes a rotary table; 1402, a crushing roller; 1403, an air ejection hole; 1404, a casing;
Reference numeral 406 denotes a sensor.

On the other hand, although this is also a measure against vibration, there is a technique of spraying water to the coal seam in the pulverizing section (pulverizing section water injection) (Japanese Patent Publication No. 6-85881 shown in FIG. 16). This technique aims to stabilize the trajectory of the crushing roller by moistening the powder layer so that the powder layer does not easily collapse. In FIG. 16, reference numeral 1502 denotes a liquid ejection nozzle.

However, only one of these techniques cannot cope with vibration suppression during the mill stop process as shown in FIG. For example, it is difficult to apply the air blow method to the vibration during the load reduction process. During the unloading process, many coal seams accumulated in the mill are discharged to the furnace,
The temperature and pressure of the main steam fluctuate.

On the other hand, if air blowing is performed, coal output is further increased, and disturbance to the pressure and temperature characteristics of the main steam increases, which is not preferable. Therefore, it can be said that in the process of reducing the load, it is better to inject the water in the pulverizing section, which acts to suppress coal output.

With respect to self-excited vibration after stopping the coal feeder, if water is injected into the pulverizing section, the coal seam on the rotary table may become wet and solidified, and may remain as residual coal even after the mill is stopped.
Such residual charcoal may be ignited by hot air input during restart.

Therefore, the pulverizing section injection method cannot be used after the coal feeder is stopped. After the stop of the coal feeder, the air blow method is preferable in order to remove the coal seam on the rotary table as soon as possible.

The air blow method is intended to remove fine powder by breaking the coal seam, whereas the water injection method in the pulverizing section is a method of hardening even a coal seam containing fine powder so that it is hard to break and becomes stable. Both methods do not work at the same time. In other words, the air blow method and water injection method shown here are:
It is necessary to use them properly.

[0029]

When the self-excited vibration as described above occurs in the roller mill, (1) the reliability of the mill itself and peripheral equipment is impaired.

(2) Employees in the plant feel discomfort.

Because of the above problems, it is necessary to prevent the occurrence of self-excited vibration.

On the other hand, in order to avoid the self-excited vibration, (1) reduce the rotation speed of the classifier.

(2) Reduce the grinding load.

Although measures such as these are effective, in any case, the grain size at the mill outlet becomes coarse, and in the pulverized coal-fired boiler, the combustion characteristics in the boiler furnace deteriorate. That is, combustion is sacrificed. Therefore, the problem of self-excited oscillation hinders improvement of combustion characteristics such as reduction of NOx concentration in exhaust gas, unburned portion in ash, or CO concentration.

An object of the present invention is to provide a fluid jet apparatus and method for a roller mill which can prevent self-excited vibration in the roller mill and stably operate the roller mill.

[0036]

In order to achieve the above-mentioned object, the present invention employs the following means.

Dedicated nozzles for jetting water and air are provided in the mill, and air jets and water spray are sprayed from these nozzles onto the powder layer on the rotary table. These nozzles
A plurality of crushing rollers are provided in gaps. In the case of a roller mill having three crushing rollers, there are also three gaps where nozzles are provided. With respect to three gaps in the mill, air is sprayed into one gap and water is sprayed into the remaining two gaps. Alternatively, water can be sprayed into one gap and air can be injected into the other two gaps.

On the other hand, nozzles for water injection and air injection are arranged side by side in all three gaps. That is, it is possible to provide three nozzles for water injection and three nozzles for air injection, respectively, for a total of six nozzles.

Water and air are not injected at the same time. Water and air are selectively used according to the state of the coal seam in the pulverizing section of the mill and the operating conditions of the mill.

For example, in the process of stopping the mill, water is injected in the process of reducing the load (reducing the amount of coal supplied), and after the coal feeder is stopped, air is injected.

In this manner, by properly using the ejection of both fluids, self-excited vibration is prevented from being generated under any operating conditions.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the structure of a roller mill provided with a fluid ejection device according to the present invention.

An air nozzle 12 and a water nozzle 16 are provided in the biting portion of each crushing roller. The air is applied to the raw material powder layer 3 on the turntable 2, which causes the generation of vibration.
The air is blown off (air blown), is guided from the air header 10 through the air supply pipe 11, is jetted from a plurality of air nozzles 12, and collides with the raw material powder layer 3 as an air jet 13.

The water is used to moisten the raw material powder layer on the turntable 2 to reduce the fluidity and to stabilize the raw material powder layer. The water is supplied from the water nozzle 16 through the water supply header 14 and the water supply pipe 15. The water is sprayed on the raw material powder layer 3 as indicated by reference numeral 17.

Other configurations and functions of the roller mill are the same as those shown in FIG. 14, and thus are omitted here and will be described later.

The feature of the present invention resides in that air injection (air blowing) and water injection are performed in combination on the raw material powder layer 3 in the same roller mill as described below.

FIG. 2 shows the first embodiment, and is a view from above a pulverizing unit. In this crushing section,
The crushing roller 1 is moved 3 degrees in the circumferential direction of the rotary table 2.
Are arranged. Since there are three grinding rollers 1, there are also three gaps between the grinding rollers 1 and 1. An air nozzle 12 is provided in one gap, and an air jet 22 is ejected. This air is compressed air 18 and is led through a compressed air supply line 20.

On the other hand, the water nozzle 1
6 are provided, and at these positions, toward the powder layer 3,
Water is sprayed as indicated by reference numeral 23. The water 19 is supplied through a water supply line 21 that is provided so as to wind around the housing 6. FIG. 3 shows a second embodiment. Contrary to the first embodiment shown in FIG. 2, in three gaps, one spray has a water spray 23,
An air jet 22 is blown onto the powder layers in the other two gaps.

As in the first embodiment shown in FIG. 2, both compressed air 18 and 19 are introduced into a mill through a compressed air supply line 20 and a water supply line 21 which are piped so as to be wound around the housing 6, and air nozzles are respectively provided. The water is sprayed from the water nozzle 12 and the water nozzle 16 toward the coal seam in the pulverizing section.

The water 19 and the compressed air 18 are not sprayed at the same time, but are sprayed selectively according to the state of the coal seam in the pulverizing section and the operating conditions of the mill. To prevent the occurrence of

FIG. 4 shows an embodiment according to the third embodiment in which an air nozzle 12 and a water nozzle 16 are arranged in parallel in three gaps between the crushing rollers 1 and 1. is there. That is, there are three air nozzles 12 and three water nozzles 16 each.

In this figure, from three air nozzles 12,
The situation where an air jet is injected is schematically depicted. The supply of the water 19 is stopped, and only a small amount of air for preventing blockage is leaked from the water nozzle 16. Both compressed air 18 and water 19 are supplied to the mill housing 6.
It is piped so that it can be wound around. The jet is injected from the air nozzle 12 and the water nozzle 16 through the compressed air supply line 20 and the water supply line 21, respectively, and makes the jet collide with a coal seam (omitted in this figure).

FIG. 5 shows the air nozzle 12 and the water nozzle 16.
1 schematically illustrates a supply system of compressed air 18 and water 19 with respect to FIG.

In this embodiment, the water line valve 24
Is “open”, and a water spray 23 is jetted from the water nozzle 16. Further, the air line valve 25 is closed, and nothing is ejected from the air nozzle 12.

Water supply line 21 and compressed air supply line 2
0, a communication valve 26 is interposed. By opening the communication valve 26, one of the water 19 and the air 18 is concentrated from both of the water nozzle 12 and the air nozzle 16. It can be sprayed.

For example, when only water 19 is injected from both nozzles 12 and 16, the water line valve 24 is closed,
The communication valve 26 is opened.

FIG. 6 shows another embodiment different from the supply system shown in FIG. In this example, the compressed air supply line 20 and the water supply line 21 are not connected, and each fluid is ejected from the independent air nozzle 12 and water nozzle 16. The water supply line 21 is provided with a line for guiding the leak air 28,
Is not injected, the leak air 28 is kept flowing to prevent the water nozzle 16 from being clogged. When water 19 is injected from the water nozzle 16, the leak air valve 27 is closed to stop the flow of the leak air 28.

Injecting and moistening the powder layer 3 is intended to strengthen the powder layer 3 by increasing the adhesion between the particles. When a small amount of water adheres, as shown in FIG. 7, a water film cross-link 30 is formed, and the coal particles 29 are formed by the action of surface tension.
They come to attract each other. In the grinding section of the roller mill,
Since the powder layer 3 always moves while being mixed, FIG.
The phenomenon that has occurred on the surface portion of the substrate 3 permeates into the entire powder layer 3.

In this way, the entire powder layer 3 in the pulverizing portion of the roller mill or the powder layer 3 in the biting portion of the pulverizing roller 1 is moistened, and the powder layer 3 becomes firm and stable.

By the above operation, the powder layer 3 does not collapse even by the rolling of the grinding roller 1, and self-excited vibration can be prevented.

The air blow method in which an air stream is blown to the powder layer 3 in the pulverizing section aims at the following operation.

(1) The fine particles are blown off from the powder layer 3 (a kind of classifying action) to make the powder layer 3 coarse, stable and hard to collapse.

(2) The periodic shape of the powder layer 3, which is a feedback system for self-excited vibration, is broken and changed by the force of the air flow, thereby eliminating self-excited vibration.

FIG. 8 schematically illustrates a state in which an air jet is jetted and blown from the air nozzle 12 to the raw material powder layer 3 at the biting portion of the crushing roller.

The air jet 13 collides with the raw material powder layer 3, disturbs the powder layer 3, and blows off fine powder in the powder layer 3 as indicated by reference numeral 31. When the fine powder is mixed in the powder layer 3, the powder layer 3 easily flows and collapses. The operation in the air blow is such that the fine powder is blown off from the powder layer 3 at the biting portion of the crushing roller 1 so that the crushing roller 1 bites coarse particles as indicated by reference numeral 32.

With the above-described operation, the powder layer 3 into which the grinding roller 1 bites is stable and hard to collapse, so that the occurrence of self-excited vibration is suppressed.

FIG. 9 shows that even with the same action of air blow,
It is a diagram schematically illustrating a behavior of changing a shape of a powder layer by air blowing.

When the pulverizing roller 1 on the upstream side vibrates (α), the raw material powder layer 3 changes periodically under the influence of the vibration, and becomes a wavy powder layer 33. Such a wavy powder layer 33
Is a phenomenon called "corrugation", but when the downstream grinding roller bites the wavy powder layer 33, it vibrates in the same manner as the upstream grinding roller 1.

This phenomenon is the feedback mechanism of the self-amplification system. As the wave-like deformation of the raw material powder layer 3 develops, the self-excited vibration is amplified.

The air jet 13 ejected from the air nozzle 12
Collides with the raw material powder layer 3 so that the powder layer 3
The feedback system is divided by deformation as shown in FIG. Even when the crushing roller 1 causes self-excited vibration, the developed self-excited vibration does not reach due to the action of deforming the powder layer 3 as described above.

When this air blow is performed on the powder layer in the pulverizing section, the action of removing fine particles in FIG. 8 and the action of deforming the powder layer in FIG. 9 do not occur independently of each other. While they are mixed.

FIG. 10 shows the effect of suppressing self-excited vibration during the load reduction process (FIG. 13), and compares the embodiment of the present invention with the conventional technology (in the case of no countermeasures). .

The amplitude δ _OC1 was made dimensionless by dividing by the amplitude δ _OC1 * of the self-excited vibration at the time of no measures.

That is, the amplitude level without any countermeasures is
δ _OC1 / δ _OC1 * = 1. From these results, by implementing the present invention, δ _OC1 / δ _OC1 * = 0.31
It can be seen that the vibration can be reduced to the level of.

In the present invention, in this deloading process,
Water is injected into the crushing section, and the above-described vibration suppression effect is due to the wetting of the coal seam.

FIG. 11 summarizes the effect of suppressing self-excited vibration (of FIG. 13) generated after stopping the coal feeder.

Also in this vibration, the amplitude δ _{OC2 is changed} to the amplitude δ _OC2 * when no measures are taken. Dimensionless by dividing by. That is, the amplitude level in the case of no measures is δ
_OC / δ _OC * = 1.

In the embodiment of the present invention, after the coal feeder is stopped, the injection from the pulverizing section is switched to the air blow. Due to the action of air blow, the amplitude level is changed to δ _OC2 /
It is also clear from this result that δ _OC2 * can be significantly reduced to 0.22.

As described above, even after the deloading process and after the coal feeder was stopped, the self-excited vibration substantially disappeared, and the effect of the present invention has been demonstrated.

As shown in FIG. 13, during the process of purging and emptying the powder layer from the pulverizing section, the forced vibration becomes intense. This vibration has no problem because it does not have a self-amplifying property, but it is preferable that the level of forced vibration be low.

In the present invention, even in the process of emptying the pulverizing section, air blow is performed to expel the powder layer from the pulverizing section as soon as possible and to reduce the forced vibration. This air blow is continuously performed after the stop of the coal feeder ().

FIG. 12 shows the result of comparison with the case where no countermeasure is taken. It can be seen that the present invention can reduce the amplitude of the forced vibration to about 1/3.

Assuming that the amplitude at the time of no countermeasure is δ _OC3 / δ _OC3 * = 1, according to the present invention, not only the self-excited vibration generated when a certain amount of powder layer exists in the pulverizing part, but also the mill This proved to be effective in reducing the forced vibration generated immediately before the stop.

The embodiment of the present invention has been described above with reference to a roller mill (FIG. 1) in which three grinding rollers are supported below a triangular pressure frame having an integral structure.

The fluid jetting apparatus and method according to the present invention are applied to a roller mill in which each grinding roller is independently supported by an arm like a cantilever (for example, FIGS. 15 and 1).
6) can be applied almost directly to the self-excited vibration.

In the present invention, if water is injected into the coal bed of the pulverizing section, the surface of the coal particles becomes slightly wet, so that the adhesion between the particles increases, the mechanical strength of the entire coal bed increases, and the coal bed hardly collapses. Become. Therefore, the crushing roller stably rolls on the coal seam, and as a result, self-excited vibration does not occur. In the process of reducing the load on the mill, the coal bed in the pulverizing section becomes finer with time, and the vibration becomes extremely liable to occur. However, the coal bed having fine particles is stabilized by water injection into the pulverizing section.

On the other hand, the air blow method blows off fine powder in a coal seam in a pulverizing section. A coal bed containing fine powder is likely to flow and is unstable. After the coal feeder is stopped, if the fine powder is blown off and removed from the coal seam by air blow, the coal seam becomes coarse and firm, and self-excited vibration does not occur.

As described above, after the coal feeder is stopped, the rotary table may be directly wetted with water (this may be a cause of corrosion destruction), and the rotary table may be further solidified with water. If it remains above, there is also a danger of ignition due to hot air being injected at restart.

The air blow performed instead is a method of discharging excess pulverized coal in the pulverizing section into the furnace, and is therefore effective from the viewpoint of accelerating the purging of residual coal.

By the operation described above, if the operation of switching between water injection into the pulverized section coal seam and air blow is performed as in the present invention, particularly in the process of stopping the mill (burner extinguishing), even during the reduction of the load, the coal supply is continued. Even after the machine stops and the mill stops (rotation of the rotary table stops), occurrence of self-excited vibration can be prevented. The metal pulverized surface of the turntable does not get wet, and the residual coal can be purged perfectly.

[0091]

The effects of implementing the present invention are summarized as follows.

(1) The mill can be operated quietly without causing self-excited vibration during steady operation at low load or high load, and under any operation conditions such as a mill stop process.

(2) Operational restrictions such as a reduction in the number of revolutions of the classifier and a reduction in the hydraulic pressure applied to the crusher are eliminated. As a result, the pulverizing ability is improved, the particle size at the mill outlet is reduced, and the amount of coal dropped from the air throat is reduced.

(3) Quiet operation is possible even with coal that is likely to cause vibration, and relatively flame-retardant coal having a high fuel ratio can be pulverized to a fine particle size.

(4) In connection with the effect (2), the combustion characteristics are improved, so that NOx and unburned ash are reduced.

(5) Since the vibration can be prevented, the reliability of the mill itself and peripheral equipment is improved.

(6) Even when air blowing is not performed, that is, when high-speed air is not injected, the nozzle is not clogged by the action of air leak.

(7) Since the residual coal accumulated in the mill can be effectively purged, troubles such as spontaneous ignition and explosion of the coal in the mill can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a roller mill equipped with a fluid ejection device according to the present invention.

FIG. 2 is a configuration diagram illustrating a first embodiment of a fluid ejection device in a roller mill.

FIG. 3 is a configuration diagram showing a second embodiment of the fluid ejection device in the roller mill.

FIG. 4 is a configuration diagram showing a third embodiment of a fluid ejection device in a roller mill.

FIG. 5 is a configuration diagram illustrating an example of a fluid supply system.

FIG. 6 is a configuration diagram showing another example of the fluid supply system.

FIG. 7 is a schematic diagram showing a mechanism of a pulverizing unit by water injection.

FIG. 8 is a schematic diagram showing a behavior of a powder layer of a pulverizing unit by air injection.

FIG. 9 is a schematic diagram showing a behavior of a powder layer of a pulverizing unit by air injection.

FIG. 10 is an explanatory diagram showing effects obtained by implementing the present invention.

FIG. 11 is an explanatory diagram showing effects obtained by implementing the present invention.

FIG. 12 is an explanatory diagram showing effects obtained by implementing the present invention.

FIG. 13 is a characteristic diagram for explaining a problem of vibration occurring in a conventional roller mill.

FIG. 14 is an overall schematic view of a general roller mill.

FIG. 15 is a configuration diagram of a main part of a roller mill according to a conventional example.

FIG. 16 is a main part configuration diagram of a roller mill according to another conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 crushing roller 2 rotating table 3 raw material powder layer 4 crushed raw material 5 raw material supply pipe 6 housing 7 rotation classifier 8 hot air 9 throat vane 10 air header 11 air supply pipe 12 air nozzle 13 air jet 14 water supply header 15 water supply pipe 16 water Nozzle 17 Watering 18 Compressed air 19 Water 20 Compressed air supply line 21 Water supply line 22 Air jet 23 Water spray 24 Water line valve 25 Air line valve 26 Communication valve 27 Valve for leak air 28 Leak air 29 Coal particles 30 Crosslink of water film 31 Fine powder Blow off 32 Coarse coarse particles 33 Wavy powder layer 34 Deformation of powder layer

Continued on the front page (72) Inventor Hiroyuki Kaku 3-36 Takara-cho, Kure-shi, Hiroshima Pref. Inside the Kure Laboratory, Babkotsuk Hitachi, Ltd. (72) Inventor Hideo Mitsui 6-9 Takara-cho, Kure-shi, Hiroshima Pref. (72) Inventor Tadashi Hasegawa 6-9 Takaracho, Kure City, Hiroshima Prefecture Babkotsuk Hitachi Kure Plant

Claims (8)

[Claims] 1. A rotary table in a cylindrical housing having a tire-type crushing roller and a crushing race, which is a groove for rolling the crushing roller in conjunction with the crushing roller, is engraved in a circumferential direction. For the powder layer formed in the crushing section of the roller mill that crushes solid fuels and solid raw materials such as coal,
A fluid ejecting apparatus for a roller mill, wherein a water nozzle and an air nozzle for ejecting water and air independently from each other are provided toward a pulverizing section in the mill. 2. The fluid jet apparatus according to claim 1, wherein a water nozzle and an air nozzle are provided between each of the pulverizing rollers. 3. The fluid jet apparatus according to claim 2, wherein one of a water nozzle and an air nozzle is provided in a gap between each of the pulverizing rollers. 4. The fluid ejecting apparatus according to claim 3, wherein at least one water nozzle and one air nozzle are provided. 5. The fluid jet device according to claim 2, wherein nozzles for water and air are arranged in pairs in a gap between the crushing rollers. 6. A rotary table in a cylindrical housing having a tire-type grinding roller and a grinding race engraved in a circumferential direction, the grinding race being a groove for rolling the grinding roller in conjunction with the grinding roller. For the powder layer formed in the crushing section of the roller mill that crushes solid fuels and solid raw materials such as coal,
In the fluid injection method of spraying a fluid from a nozzle, a water nozzle and an air nozzle, which independently spray water and air, are installed toward a pulverizing unit in a mill, and water and air are not sprayed at the same time. A fluid injection method in a roller mill, characterized in that the two fluids are selectively used according to the state of the coal seam in the pulverizing section and the operating conditions of the mill. 7. The method according to claim 6, wherein water injection is performed by a water nozzle during a load reduction in a mill stop process, and air injection is performed by an air nozzle after the coal feeder is stopped. Fluid injection method in roller mill. 8. A rotary table in a cylindrical housing having a tire-type crushing roller and a crushing race, which is a groove for rolling the crushing roller in conjunction with the crushing roller, is engraved in a circumferential direction. For the powder layer formed in the crushing section of the roller mill that crushes solid fuels and solid raw materials such as coal,
In a fluid injection method of spraying a fluid from a nozzle, a water nozzle and an air nozzle for separately injecting water and air are installed toward a pulverizing unit in a mill, and a water supply line and an air supply line are connected via a valve. A fluid jetting method in a roller mill, characterized in that the nozzles are connected to each other so that only water or only air can be jetted from all nozzles.