JPH08629B2 - How to eliminate foreign matter trapped in a rotary valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for eliminating foreign matter trapping in a rotary valve, and more particularly to a method for eliminating foreign matter trapping between a blade of a rotary valve and a casing. is there.

[Conventional technology]

BACKGROUND ART Conventionally, a rotary valve has been often used as a means for quantitatively transferring coal or other powdery particles or transferring them while air-sealing.

FIG. 2 shows a system diagram when such a rotary valve is incorporated in a coal (fuel) supply device of a coal-fired fluidized bed boiler.

In this figure, coal cut out from a coal bunker 1 by a fixed amount by a screw feeder 2 below the coal bunker 1 flows into a pipe line 3 having a rotary valve 6 interposed therein, and the rotary valve 6 causes the inside of the pipe line 3 to flow. It is transferred to the coal dryer 5 while being air-sealed. The coal dried in the coal dryer 5 is sent from the pipeline 4 to the coal crusher 7, is crushed to a predetermined particle size, and is further passed through the pipeline 8 to the coal splitter 10.
Sent to. Here, coal is distributed to a plurality of coal supply pipes 11 and is pneumatically transported in the pipes 11 by the exhaust gas of the coal dryer 5 supplied from the pipes 9 to generate a coal-fired fluidized bed boiler.
It is supplied to 12 fluidized combustion chambers 12a. In this fluidized combustion chamber 12a, a fluidized medium such as sand is fluidized by the air for combustion and fluidization supplied from the lower portion through a dispersion plate to form a fluidized bed, and coal is continuously supplied into this. It is used for combustion. The combustion heat is transferred to the heat transfer tube via the fluid medium, and the water in the heat transfer tube evaporates to obtain steam. The combustion exhaust gas is sent to an upper desulfurization chamber 12b, desulfurized in a fluidized bed such as coal stone formed there, and then discharged. The rotary valve 6 transfers and supplies coal to the coal dryer 5 while sealing the hot air supplied from the pipe 13 to the coal dryer 5.

Such a rotary valve 6 is constructed as shown in FIG. In the figure, a shaft 16 is rotatably supported at both ends outside the casing 15 at the center of the casing 15, and a rotor 17 is fixedly attached to the shaft 16. A plurality of blades 18 (in this embodiment, 8 blades) are provided on the outer circumference of the rotor 17 at equal intervals in the circumferential direction.
The blades 18 are radially mounted, and the tips of the blades 18 are rubbed against the inner wall of the casing 15 and rotatably provided in the casing 15 by the rotation of the shaft 16. Axis 16
Although not shown, the roller chain is suspended between the sprocket attached to the shaft end of the motor and the sprocket attached to the shaft end of the motor with reduction gear, and the motor is rotated by driving the motor with reduction gear. To be done.

Then, coal is supplied from the above-mentioned pipe 3 through the inlet 6a of the rotary valve 6 into the space 19 formed by the adjacent blades 18, and the blades 18 are continuously rotated in the direction of the arrow shown in the drawing to the outlet 6b side. Sent to the outlet 6b, and then the pipeline 3
The inside is continuously supplied to the coal dryer 5. Thus, while the rotary valve 6 is sending coal, the inlet 6a side and the outlet 6b side are air-sealed.

The coal sent by the rotary valve 6, that is, the coal in the coal bunker 1 (for example, particle size of 50 mm or less) is sieved in advance to remove particles having a particle size of a predetermined value or more, and the metal piece is provided in the middle of the pipe line 3. It is removed by the magnet plate 3a, but in this coal this sieve and magnet plate
It is rare that foreign matter such as slender stones that do not cover 3a or metal pieces such as iron pieces and wires enter.

[Problems to be Solved by the Present Invention]

When such foreign matter is mixed in the coal supplied to the rotary valve 6, a stone 20 as the foreign matter is caught between the tips of the blades 18 and the casing 15 as shown in FIG. As a result, the electric motor with reduction gear for driving the rotary valve 6 becomes overloaded, the thermal relay flies and trips, and the rotary valve 6 stops. In such a situation, for example, it is necessary to open the inspection port of the rotary valve 6 to take out the clogged stone, and to recover the thermal relay of the electric motor control panel. It is troublesome, and the coal (fuel) supply system must be stopped for a relatively long time, which hinders continuous operation of the fluidized bed boiler 12, which is a serious problem.

The present invention has been made in view of the above problems, and an object thereof is to provide a method capable of automatically eliminating a bite even when a foreign substance such as a stone is bitten by a blade. It is what

[Means for solving the problem]

In order to achieve the purpose of steam, the present invention is as follows: (1) When a powder or granular material is transferred using a rotary valve in which a plurality of blades arranged at intervals in the circumferential direction are rotatably provided inside a casing. A method for eliminating the foreign matter when the blade of the rotary valve bites foreign matter, comprising the steps of: when a drive overload current of the blade of the rotary valve is detected (step 102); Is stopped (step 105), the blades of the rotary valve are stopped by a timer for a predetermined time (steps 103 and 106), the blades are reversed after the elapse of the set time of the timer (step 107), and the reverse rotation is started. At the same time, a timer is used to detect the blade drive overload current for a predetermined time (steps 108 and 109), and when the blade drive overload current is detected in this process as well. Also, the blades are stopped for a predetermined time by a timer (step 11
(0, 111), the blades are normally rotated after the elapse of the set time of the timer (step 112), and at the same time when the normal rotation is started, the blade detects the drive overload current of the blades for a predetermined time (steps 113, 114). The blade drive overload current detection time in steps 113 and 114 is set longer than the blade drive overload current detection time in steps 108 and 109, and the blade drive overload current is detected in steps 113 and 114. If not, the supply of the granular material to the rotary valve is restarted (step 116), and when the drive overload current of the blade is detected, the process returns to step 103 and subsequent steps so that the foreign matter of the blade is caught. It was configured to resolve.
(2) In the method (1), the steps 102, 1
The number of times the drive overload current of the blade is detected at 09 and 114 is added (step 104), and when the rotation exceeds a predetermined value (step 117), the rotary valve is stopped (step 118). It was constructed so that foreign matter could be caught in the blades by inspection.

[Action]

In the above configuration (1), when the overload current is detected by the current detector or the like in step 102 while the rotary valve continues to operate, the supply of the powder or granular material to the rotary valve is stopped in step 105. , At the same time, step 103
The rotation of the blade is stopped at and the timer is activated at step 106, and the blade is stopped for a predetermined time, for example, 4 seconds. Then, when the timer setting time has passed, the blade is reversely activated in step 107. Simultaneously with the start of this reverse rotation, the timer is activated in step 108, and the overload current is detected in step 109 within the set time of this timer, for example, within 4 seconds. Within the set time in the steps of 108 and 109, even when the overload current is detected or not detected, that is, when the bite is eliminated or not eliminated, in any case, In step 110, the blade reverse rotation is stopped. And
In this step 110, at the same time when the blade is stopped,
Similar to 03 and 106, the timer is activated in step 111 and the blade is stopped for a predetermined time, for example, 4 seconds. When this timer setting time has passed, the blade is returned to the normal rotation start at step 112, and at the same time as the normal rotation start, the timer is activated at step 113 and the set time of this timer,
For example, the overload current is detected in step 114 within 10 seconds. The timer setting time in step 113 is set longer than the timer setting time in step 108. Then, when the overload current is not detected within the set time in steps 113 and 114, that is, when there is no jamming or when the jamming is eliminated, the powder to the rotary valve is discharged in step 116. The supply of granules is restarted. Also, if overload current is detected,
That is, if the bite is still not eliminated, the process returns to step 103 and the subsequent steps are repeated to eliminate the foreign substance from the blade.

Therefore, in the method for eliminating foreign matter from being caught in the blades of the rotary valve having such a configuration, steps 107, 108, 10
Even if the bite is eliminated during the bite elimination process by the first reverse rotation in 9, the blade rotation is returned to the normal rotation in step 112, and the overload current is generated at the predetermined time in steps 113 and 114 during this normal rotation. Is detected, and the operation is restarted after confirming that no overload current has finally occurred, so the subsequent supply of powder and granules can be performed stably and continuously. It becomes possible. That is, in this case, by setting the timer establishment time in step 113 longer than the timer setting time in step 108, it is possible to sufficiently eliminate the factor of biting during this time, and Since it is sufficiently confirmed that there is no recurrence of packing, it is possible to stably and continuously supply the powder or granules after restarting the supply of the powder or granules.

Even when the bite is not eliminated during the bite elimination process by the first reverse rotation in steps 107, 108, and 109, the normality in steps 112, 113, and 114 is larger than that in the reverse rotation in steps 107, 108, and 109. Since the rolling time is long, the probability that the bite will be eliminated in this second attempt to eliminate the bite (trie) is high, so that the bite is totally eliminated in a short time and the bite is eliminated. Can be done efficiently.

It should be noted that at the time of stopping at step 103 and at the time of stopping at 110, step switching is performed when switching from forward rotation to reverse rotation and when switching from reverse rotation to forward rotation, respectively.
Since the rotation direction is switched by a timer in 106 and 111 after a predetermined time, the safety of the drive source, the rotary valve body, etc. can be improved without the speed reducer of the motor with a reducer for driving the blades suddenly rotating in the opposite direction. Reserved.

In the above configuration (2), the coil is prevented from being damaged by heat generated by the blade driving electric motor by stopping and starting the foreign material by repeating the operation only a predetermined number of times. Damage to the blades and casing of the rotary valve due to the drive in the engaged state is prevented, and the safety of the device is maintained.

〔Example〕

FIG. 1 is a flow chart showing an embodiment of the method of the present invention.

When the operation of the coal-fired fluidized-bed boiler 12 and its coal supply system is started (step 100), it is determined in step 101 whether the bite elimination control device is automatic or manual, and it becomes automatic. If so, go to step 102.
In addition, normally, during the operation of the fluidized bed boiler 12, the automatic-manual changeover switch of the bite elimination control device is set to be automatic. Then, when the rotary valve 6 bites the foreign matter 20 as shown in FIG. 3 and the shock relay which is the current detector operates to detect the overload current, the rotary valve 6 is stopped (step 103), and In step 104, 1 is added to the shock relay actuation number counter, and the counter number becomes 1. The counter number is set to 0 at the start of operation. At the same time, the coal screw feeder 2 is stopped (step 105). Simultaneously with the stop of the rotary valve 6, the timer starts counting in step 106, and when 4 seconds elapse, the rotary valve 66 is started in reverse rotation by the timer signal (step 107). In addition,
The reason why the rotary valve 6 is stopped and the reverse rotation is not started immediately in step 103 is that the motor with reduction gear is still rotating by its inertia even when a stop signal is given, but if the reverse rotation is suddenly activated at this time, This is because in order to damage the teeth and the like, in consideration of safety, the reverse rotation is started after the electric motor with reduction gear is completely stopped.

Reverse rotation start is started in step 107 and at the same time step 1
The timer starts counting at 08, and if the set time of this timer falls, the foreign matter is caught within 4 seconds and the bite is resolved. If the shock relay does not operate at steps 108 and 109, proceed to step 110. The rotary valve 6 is stopped. In addition, when the foreign matter that has been caught comes out from between the blade 18 and the casing 15 by the reverse rotation, the space 19 between the adjacent blades 18 is
It drops in and the bite is eliminated. Further, in step 109, if the foreign matter biting is not yet resolved and the shock relay operates to detect the overload current, in step 104, the shock relay operation number counter is further incremented by 1,
That is, 1 is added to 1 at the previous time to set the counter number to 2, and in this case as well, the routine proceeds to step 110, where the rotary valve 6 is stopped.

The rotary speed of the rotary valve 6 is, for example, 16 rpm, and the rotary speed of the rotary valve 6 is about 0.9 rotation in 4 seconds of this reverse rotation period.

Then, in the same way as in the previous steps 103 and 106, the timer starts counting in step 111 at the same time when the rotary valve 6 is stopped, and when 4 seconds of the set time is exceeded, step 112
Then, the rotary valve 6 is returned to the normal rotation start at this time, and at the same time, the timer is started to count in step 113, and step 114 is started within 10 seconds of the set time of this timer, for example.
Check if the shock relay is working. The rotary valve 6 makes about 2.2 revolutions in these 10 seconds. That is, when the shock relay does not operate due to the reverse rotation of the previous step 107 and the bite is eliminated in the step 109, the final confirmation that the bite is eliminated by the steps 113 and 114. If there is no actuation within 10 seconds, the shock relay actuation counter is reset in step 115 and the value is reset to zero. At the same time, in step 116, the coal screw feeder 2 is activated, the operation of the coal supply system is restarted, and the coal is started to be supplied to the fluidized bed boiler 12. Also, the previous step
When the shock relay is activated by 109, if the shock relay is not activated within 10 seconds in step 114, that is, if the bite is eliminated at this stage, similarly go to steps 115 and 116, and The operation of the supply system is restarted and the coal is supplied to the fluidized bed boiler 12.

On the other hand, if the bite is still unresolved in step 114 and the shock relay operates, the shock relay actuation counter is incremented by 1 in step 104, and 1 is added to the previous 2 to increase the counter number. At the same time, the routine returns to step 103 and the rotary valve 6 is stopped. The same process is repeated thereafter, and the foreign matter trapping and confirmation operation are performed. Then, during such an operation, when the count number becomes 4 in the shock relay actuation number counter operation in step 104, the step
If this is judged at 117 and it becomes 4 or more, step 1
At 18, the rotary valve 6 is stopped and the rotary valve 6 is inspected on site. The reason why the rotary valve 6 is stopped when the shock relay actuation count is 4 is that the electric motor generates heat when the stop and start (reverse rotation, forward rotation) are repeated a predetermined number of times or more, and there is a risk of coil damage. Because. Of course, the number of times is not limited to this numerical value, and may vary depending on the type of the electric motor, the capacity and the timer setting time of steps 108 and 113, and an appropriate number of times can be set according to them.

When the bite clearance control device is manually operated in step 101, if the rotary valve 6 bites a foreign object during operation, the operation of the shock relay is determined in step 119, and the rotary valve 6 is stopped in step 118. The coal screw feeder 2 is stopped in step 105.

According to the experimental results, the foreign matter 20 such as the ordinary stone as shown in FIG. 3 is almost always caught in the blade 18 by only reversing the blade 18 once. Further, when the foreign matter 20 is a relatively elongated one such as a wire, the blade 18 is effectively removed by repeating the rotation of the blade 18 in the reverse rotation and forward rotation several times, and the bite is often eliminated. It was In addition, a relatively long and flexible foreign substance such as such a wire is used for the tip of the blade 18 and the casing as shown in FIG.
In addition to being pinched between the blades 15 and biting, it may be pinched between the inner surface of the casing 15 and the end face in the width direction of the blade 18, and in such a case, as described above, the blade 18 In many cases, the biting is effectively released by repeating the reverse rotation and the forward rotation several times. The trapped foreign matter is rotated in the reverse or forward direction
When it is disengaged from between the blade 18 and the casing 15, it falls into the space 19 between the blades 18 and the blades 18 adjacent to each other, and the trapping is eliminated.

In addition, in the present embodiment, the case where the timer set time (bite elimination operation time) in step 108 and step 113 is set to 4 seconds and 10 seconds, respectively, is shown, but the present invention is not limited to this. An appropriate time can be set depending on the shape, type, etc. of the foreign matter mixed in the transferred material such as coal. In the present embodiment, the first step 10
The bite elimination operation time at 8 and 109 is, for example, 4 seconds, and the bite elimination operation time at the second steps 113 and 114 is, for example, 10 seconds. The first time is shortened and the second time is lengthened. By doing so, it is possible to more efficiently eliminate the bite.

Further, in the present embodiment, the foreign matter trapping elimination operation described above,
That is, since it is possible to end the repetitive operations of reverse rotation, stop, and forward rotation within 30 to 60 seconds, there is almost no effect on the operation of the fluidized bed boiler 12, and the fluidized bed boiler is
12 can be driven during this time. That is, the combustion chamber
Since the fluidized medium in 12a has a high amount of heat possessed, even if the supply of fuel (coal) is stopped during this period, it is not greatly affected by steam generation, and after the bite is removed, it remains as it is. The coal supply can be started and the operation can be continued.

〔The invention's effect〕

As is clear from the above description, according to the configuration of claim 1, when foreign matter is caught in the blade in the normal rotation state, the blade reverses at least in steps 107, 108 and 109 and step 112 from the normal rotation state. , 113, 114 are normally rotated (returned to the original rotation) of the blades, it is possible to more reliably eliminate the trapping of foreign matter. That is,
Even when the bite is not eliminated during the bite elimination process by the first reverse rotation in steps 107, 108, and 109, the step 112,
Since the forward rotation time at 113 and 114 is lengthened, the probability that the bite will be eliminated by this second attempt to eliminate the bite is increased,
Therefore, it is possible to perform the bite elimination as a whole in a short time and efficiently perform the bite elimination.

Further, even when the bite is eliminated during the bite elimination process by the first reverse rotation in steps 107, 108, and 109,
In step 112, the rotation of the blades is returned to normal rotation, and during this normal rotation, the presence or absence of overload current is detected for a predetermined time by steps 113 and 114, and finally there is no occurrence of overload current. Since the operation is restarted after confirming that, it is possible to stably and continuously supply the powdery particles thereafter. That is, in this case, by making the timer setting time in step 113 longer than the timer setting time in step 108, it is possible to sufficiently eliminate the factor of biting during this period,
Since it is sufficiently confirmed that there is no recurrence of biting, it is possible to stably and continuously supply the powdery particles after restarting the supply of the powdery particles.

It should be noted that at the time of stopping at step 103 and at the time of stopping at 110, when switching from normal rotation to reverse rotation, and
When switching from reverse rotation to forward rotation, step 106
Since the rotation direction is switched by the timer in 111 and 111 after a predetermined period of time, the safety of the drive source and the rotary valve body etc. can be improved without the speed reducer of the motor with a reducer for driving the blades being suddenly rotated in the opposite direction. Can be secured.

The above-mentioned bite elimination operation can be performed automatically and can be performed in a short time.The foreign substance bite elimination time can be shortened compared to the conventional inspection at the time of foreign substance biting and foreign substance removal work. It can be remarkably shortened and the transport efficiency of powder and granules can be improved.

Therefore, when this method is applied to, for example, a rotary valve of a coal (fuel) supply system of a coal-fired fluidized bed boiler, it is not necessary to completely stop the operation of the boiler, and the boiler can be continuously operated. It is possible to improve the operation management.

According to the configuration of claim 2, in addition to the above effect, further, stop and start due to foreign matter being caught are repeated only a certain number of times, so that damage to the coil due to heat generation of the blade driving motor is prevented, It is possible to prevent the blade of the rotary valve and the casing from being damaged by the drive of the electric motor as well as the drive in which foreign matter is caught, and it is possible to maintain the safety of the device.

[Brief description of drawings]

FIG. 1 is a flow chart showing an operation sequence for eliminating foreign matter trapping in an embodiment of the present invention, FIG. 2 is a system diagram of a fuel supply device to which the present invention is applied, and FIG. 3 is a rotary valve to which the present invention is applied. FIG. 1 ... Coal banker, 2 ... Coal screw feeder, 5
...... Coal dryer, 7 ...... Coal crusher, 10 ...... Coal splitter, 11 ...... Coal supply pipe, 12 ...... Coal-fired fluidized bed boiler, 6 ...... Rotary valve, 15 ...... Casing,
18 …… feather, 19 …… space, 20 …… stone (foreign matter).

Claims (2)

[Claims] 1. A rotary valve in which a plurality of blades arranged at intervals in the circumferential direction are rotatably provided inside a casing, and when the powder or granular material is transferred, the blades of the rotary valve catch foreign matter. Then, when the drive overload current of the blade of the rotary valve is detected (step 102), the supply of the granular material to the rotary valve is stopped (step 105). At the same time, the blade of the rotary valve is stopped by the timer for a predetermined time (steps 103 and 106), and the blade is rotated in reverse after the set time of the timer has elapsed (step 107). The overload current is detected (steps 108 and 109), and the blade is driven for a predetermined time by the timer whether or not the blade drive overload current is detected during this process. Only is stopped (step
110, 111), the blades are normally rotated after the elapse of the set time of the timer (step 112), and at the same time as the start of the normal rotation, the timer detects the blade drive overload current for a predetermined time (steps 113, 114). The blade drive overload current detection time in steps 113 and 114 is set to the steps 108 and 109.
The blade drive overload current detection time is set longer than the blade drive overload current detection time, and when the blade drive overload current is not detected in steps 113 and 114, the supply of the granular material to the rotary valve is restarted (step 116). A method for eliminating foreign matter trapping in a rotary valve, wherein when foreign matter drive overload current is detected, the procedure returns to step 103 and subsequent steps to eliminate foreign matter trapping in the blade. 2. The number of times the blade drive overload current is detected in steps 102, 109 and 114 is added to each other (step
104), when the number of times exceeds a predetermined value (Step 1
17. The method for eliminating foreign matter trapping in a rotary valve according to claim 1, wherein 17) stops the rotary valve (step 118) and checks the rotary valve to eliminate foreign matter trapping in the blade. .