JP2009275882A - Purge air controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a purge air controller maintaining a long service life of a gate disk by eliminating abrasion of the gate disk, and preventing accumulating of ash in slits. <P>SOLUTION: The purge air controller includes a purge air supply source 1 supplying purge air to the slits 13, 14, a solenoid valve (a control valve) 2 supplying or stopping the purge air from the purge air supply source 1, an air cylinder (a gate driving means) 9 carrying out opening and closing operation of the gate disk 7, an air driving part 10 supplying air to the air cylinder 9 to drive a cylinder, a limit switch 6 detecting an opened or closed state of the gate disk 7, and a control unit (a control part) 5 controlling the solenoid valve 2 and the air driving part 10 on the basis of a signal of the limit switch 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a purge air control device, and more particularly, it is effective to use ash deposited in a slit existing between a gate disk and an ash conveyance pipe provided in an ash conveyance pipe for conveying ash generated from a flue gas desulfurization apparatus. It is related with the technology to remove automatically.

In a power plant, a boiler is heated using coal or heavy oil as fuel, and a generator is rotated using high-pressure steam generated therefrom as a power source. In particular, in a power plant that uses coal as a fuel, sulfur oxides contained in the flue gas are removed by a flue gas desulfurization device, and the flue gas is discharged. Moreover, in order to collect | recover the ash collect | recovered from flue gas desulfurization equipment, and to ship and ship, it is conveyed using ash conveyance piping from a power generation equipment to a jetty.
FIG. 9 illustrates a part of a conventional ash conveying pipe. The ash transport pipe 103 is provided with a gate disk 107 in the gate portion for transporting ash or stopping the transport. Further, since ash accumulates in the slits 113 and 114 when the gate disk 107 is closed, purge air is always supplied from the purge air supply source 101 to the slits 113 and 114 to remove the ash. The pressure of the purge air is appropriately adjusted by the manual valve 141 and supplied.
Patent Document 1 discloses that solid content in a fluid such as slurry that has entered the slit and the annular space is prevented from being consolidated, and that the adhesiveness between the knife plate and the seat ring is well maintained, and the cutoff performance is improved. An improved knife gate valve is disclosed.
JP 2004-124997 A

However, in the conventional ash conveying pipe shown in FIG. 9, purge air is constantly injected to remove the ash accumulated in the slits 113 and 114. Therefore, when the gate disk 107 is closed, the purge air is not When hitting the gate disk 107, the portion is worn and worn, and in the worst case, there is a problem of perforation.
In addition, the conventional technique disclosed in Patent Document 1 has a problem that the configuration of the seat ring is complicated in order to improve the adhesion between the knife gate and the seat ring.
The present invention has been made in view of such problems, and by detecting the opening and closing of the gate disk and injecting purge air only when the gate disk is open, wear of the gate disk is eliminated, and An object of the present invention is to provide a purge air control device that maintains a long life and prevents ash from accumulating in a slit.

In order to solve this problem, the present invention provides a gate disk that is provided in the middle of an ash conveying pipe that conveys the ash generated from the flue gas desulfurization apparatus, and that opens and closes the flow path of the ash conveying pipe. A purge air control device for removing ash accumulated in a slit existing between the ash conveying pipe and supplying or stopping a purge air supply source for supplying purge air to the slit and a purge air from the purge air supply source A control valve; and a gate drive means for opening and closing the gate disk; and a control part for controlling the control valve and the gate drive means, wherein the control part is in a state where the gate disk is in an open state. The control valve is controlled to supply the purge air to the slit.
The conventional purge air control device always injects purge air into the slit in order to remove ash accumulated in the slit. Therefore, there is no particular problem when the gate disk is open, but when the gate disk is closed, purge air is injected to a specific part of the gate disk, so that when the part is worn and extreme There was a problem of opening a hole. Therefore, in the present invention, the purge air is injected only when the gate disk is open, and the purge air injection is stopped when the gate disk is closed. Thereby, wear of the gate disk can be eliminated, the life of the gate disk can be kept long, and ash can be prevented from being deposited in the slit.

Claim 2 comprises a limit switch for detecting the open / closed state of the gate disk, and the controller controls the control valve to supply the purge air when the limit switch detects the opening of the gate disk, When the limit switch detects the closing of the gate disk, the purge valve is stopped by controlling the control valve.
To detect the opening and closing of the gate disk, it is possible to detect the movement of the gate disk. As a method, a striker is provided on the gate disk, and a limit switch is provided at the position of the striker when the gate disk is closed and the position of the striker when the gate disk is opened. Thus, the control means can accurately recognize the open / closed state of the gate disk by detecting the state of the limit switch.

According to a third aspect of the present invention, when the limit switch detects the opening start of the gate disk, the control unit controls the control valve to supply the purge air for a predetermined time, and the limit switch completes the opening of the gate disk. When this is detected, the purge air is continuously supplied by controlling the control valve again.
When the opening of the gate disk is started, ash enters the slit on the leading end side of the gate disk from the gap of the gate disk. In addition, a predetermined time is required until the gate disk passes through the slit on the gate disk end side. Therefore, in the present invention, when the gate disk passes through the slit on the leading end side of the gate disk, purge air is jetted for a predetermined time at that time. Since the purge air has a high pressure in the first injection, the ash removal capability is high. When the limit switch detects the completion of the gate disk opening, the purge air is continuously supplied again. Thereby, the ash deposited in the slit on the gate disk front end side can be efficiently removed.

According to a fourth aspect of the present invention, the limit switch includes: a closed limit switch that detects that the gate disk is completely closed; and an open limit switch that detects that the gate disk is completely opened; A change from a state in which the completion of closing of the gate disk is detected to a different state is regarded as a start of opening of the gate disk.
The gate disk has a predetermined length and requires a predetermined time to open and close. That is, when a closed limit switch for detecting that the gate disk is closed at a predetermined position and an open limit switch for detecting that the gate disk is opened at a predetermined position are provided, for example, the gate disk is at a predetermined position. If the closed limit switch is ON when the gate disk is closed, the fact that the closed limit switch is turned OFF from the ON state can be considered to have moved in the direction in which the gate disk is opened. That is, it can be regarded as the start of opening. Thereby, the moving direction of the gate disk can be detected from the two states of each switch.

According to a fifth aspect of the present invention, the control valve is constituted by an electromagnetic valve that opens and closes the valve depending on the presence or absence of an electric current.
In order to automatically control the supply and stop of the purge air, it is necessary to provide an electrically operated valve in the middle of the pipe of the purge air supply source. Therefore, in the present invention, the control valve is constituted by an electromagnetic valve. Thereby, opening and closing of a control valve can be controlled based on the signal from a control part.
A sixth aspect of the invention is characterized in that the gate driving means is constituted by an air cylinder driven by the force of air.
In general, the diameter of the ash transport pipe is considerably large in order to efficiently transport a large amount of ash. The width of the gate disk is required to be greater than this diameter, and a certain amount of strength is required to close the ash, which inevitably increases the weight. Since the gate driving means moves the gate disk up and down or left and right, a large driving power is required. Therefore, in the present invention, an air cylinder is used as the gate driving means. Thereby, it is possible to flexibly cope with a large driving force and a fluctuation in driving load.

According to the present invention, the purge air injection timing is performed when the gate disk is open, and when the gate disk is closed, the purge air injection is stopped. It is possible to maintain a long life and prevent ash from being deposited on the slit.
In addition, since the gate disk is provided with a striker, and the limit switch is provided at the position of the striker when the gate disk is closed and the position of the striker when the gate disk is opened, the control means can detect the state of the limit switch. Can accurately recognize the open / closed state of the gate disk.
Moreover, when the gate disk passes through the slit on the front end side of the gate disk, purge air is jetted for a predetermined time at that time, and when the limit switch detects the completion of opening of the gate disk, the purge air is continuously supplied again. Ashes accumulated in the slit on the front end side of the disk can be efficiently removed.
Further, if the closed limit switch is ON when the gate disk is closed at a predetermined position, the fact that the closed limit switch is turned OFF from the ON state is considered to have moved in the direction in which the gate disk is opened. I can lose weight. That is, since it can be regarded as the start of opening, the moving direction of the gate disk can be detected from the two states of each switch.
In addition, since the control valve is configured by an electromagnetic valve, the opening and closing of the control valve can be controlled based on a signal from the control unit.
In addition, since an air cylinder is used as the gate driving means, it is possible to flexibly cope with large driving force and fluctuations in driving load.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
FIG. 1 is a schematic view for explaining a state in which the gate disk is closed by the purge air control device of the present invention. This purge air control device is provided in the middle of an ash conveyance pipe 3 that conveys ash generated from a flue gas desulfurization apparatus (not shown), and includes a gate disk 7 that opens and closes the flow path of the ash conveyance pipe 3 and the ash conveyance pipe 3. A purge air control device that removes ash deposited in the slits 13 and 14 existing between them, a purge air supply source 1 that supplies purge air to the slits 13 and 14, and an electromagnetic that supplies or stops purge air from the purge air supply source 1 A valve (control valve) 2, an air cylinder (gate driving means) 9 that opens and closes the gate disk 7, an air drive unit 10 that supplies air to the air cylinder 9 to drive the cylinder, and opens and closes the gate disk 7 Limit switch 6 that detects the state, and a control unit that controls the solenoid valve 2 and the air drive unit 10 based on a signal from the limit switch 6 Is constituted by a control unit) 5, a.
The slits 13 and 14 are provided with seal members 11a and 11b and 12a and 12b, respectively, so that the ash 4 does not flow from the flow paths 4a and 4b when the gate disk 7 is closed as shown in FIG. Yes. Further, the limit switch 6 includes a closed limit switch 6a that detects a state in which the gate disk 7 is completely closed, and an open limit switch 6b that detects a state in which the gate disk 7 is completely opened.
In FIG. 1, the closed limit switch 6a is ON and the open limit switch 6b is OFF. At this time, the control unit 5 closes the valve of the electromagnetic valve 2 so that the purge air from the purge air supply source 1 does not flow into the pipe 16.

FIG. 2 is a schematic view for explaining a state in which the purge air control device of the present invention opens the gate disk. The same components will be described with the same reference numerals as in FIG. In FIG. 2, the control unit 5 drives the air cylinder 9 in the direction of arrow B through the air driving unit 10 to open the gate disk 7. Thereby, the limit switch 6a is turned OFF and the limit switch 6b is turned ON. At this time, the control unit 5 opens the valve of the electromagnetic valve 2 and supplies the purge air from the purge air supply source 1 to the pipe 16.
That is, the conventional purge air control device always injects purge air into the slit in order to remove the ash accumulated in the slit. Therefore, there is no particular problem when the gate disk is open, but when the gate disk is closed, purge air is injected to a specific part of the gate disk, so that when the part is worn and extreme There was a problem of opening a hole. Therefore, in this embodiment, the purge air injection timing is performed when the gate disk 7 is open, and when the gate disk 7 is closed, the purge air injection is stopped. Thereby, wear of the gate disk 7 can be eliminated, the life of the gate disk 7 can be kept long, and ash can be prevented from being deposited in the slits 13 and 14.
Further, the opening / closing of the gate disk 7 can be detected by detecting the movement of the gate disk 7. As the method, a closed limit switch 6a and an open limit switch are provided at the position of the striker 8 when the gate disk 7 is closed and the position of the striker 8 when the gate disk 7 is opened and the position of the striker 8 when the gate disk 7 is opened. It becomes possible by providing 6b. Thus, the control unit 5 can accurately recognize the open / closed state of the gate disk 7 by detecting the state of the limit switch 6.

  FIG. 3 is a view for explaining the flow path around the slit, FIG. 3 (a) is a view showing the flow path when the tip of the gate disk 7 is removed from the slit 13, and FIG. It is a figure which shows a flow path when the front-end | tip of the gate disk 7 slips out from. As shown in FIG. 3 (a), when the tip of the gate disk 7 is removed from the slit 13, if the purge air is injected from the air injection port 16a, a flow path a is generated in the ash transport pipe 3 and rides on the flow. Thus, purge air is generated as in the flow path b. Further, as shown in FIG. 3 (b), when the tip of the gate disk 7 is removed from the slit 14, when the purge air is injected from the air injection port 16b, the flow path a is generated in the ash conveying pipe 3. Along with this flow, purge air is generated as in the flow path c. Thus, by providing the injection ports 16a and 16b for injecting purge air in the slits 13 and 14, ash accumulated in the slits can be efficiently removed.

FIG. 4 is a flowchart for explaining the operation of the purge air control apparatus according to the first embodiment of the present invention. FIG. 5 is a timing chart of each part corresponding to the flowchart of FIG. This will be described with reference to FIGS.
First, it is assumed that the gate disk 7 is closed. At this time, the solenoid valve 2 is closed. From this state, the control unit 5 controls the air drive unit 10 to open the gate disk 7 (S1). When the gate disk 7 starts to open (point a), the closed limit switch 6a is turned off (point b) (YES in S2). When detecting that the closed limit switch 6a is turned OFF, the control unit 5 opens the electromagnetic valve 2 (point c) (S3). As a result, purge air is injected into the slit 13 (point d) to remove accumulated ash. At this time, the purge air has a high pressure immediately after injection, but gradually decreases to a constant value. Since the gate disk 7 continues to open, the control unit 5 monitors whether the open limit switch 6b is turned on (S4). When the open limit switch 6b is turned on (point e) (YES in S4), a predetermined time t is counted (S5), and the air drive unit 10 is controlled to stop the gate disk 7 (point f). (S6). Here, the predetermined time t may be zero. In this state, the opening of the gate disk 7 is completed, and purge air is continuously injected into the slits 13 and 14.

  Next, when the control unit 5 determines that the gate disk 7 is to be closed, the air drive unit 10 is controlled to close the gate disk 7 (point g) (YES in S7). Then, it is monitored whether the open limit switch 6b is turned off (S8). When the open limit switch 6b is turned off (point h) (YES in S8), the solenoid valve 2 is closed (point i) and the purge air is stopped. (J point) (S9). In this state, since the gate disk 7 continues the closing operation, the control unit 5 monitors whether the closing limit switch 6a is turned on (S10). When the closing limit switch 6a is turned on (point k), the closing operation of the gate disk 7 is stopped (point l) (S11). Thereafter, when the control unit 5 determines to release the gate disk 7 (YES in S12), the process returns to step S1 and is repeated.

FIG. 6 is a flowchart for explaining the operation of the purge air control apparatus according to the second embodiment of the present invention. FIG. 7 is a timing chart of each part corresponding to the flowchart of FIG. This will be described with reference to FIGS.
First, it is assumed that the gate disk 7 is closed. At this time, the solenoid valve 2 is closed. From this state, the control unit 5 controls the air drive unit 10 to open the gate disk 7 (S11). When the gate disk 7 starts to open (point a), the closed limit switch 6a is turned off (point b) (YES in S12). When detecting that the closed limit switch 6a is turned OFF, the control unit 5 opens the electromagnetic valve 2 for a predetermined time (point c) after the time t1 has elapsed (YES in S13) (S13).
As a result, purge air is injected into the slit 13 (point d) to remove accumulated ash. At this time, the pressure of the purge air is high immediately after injection, but gradually decreases. Since the gate disk 7 continues to open, the control unit 5 monitors whether the open limit switch 6b is turned on (S14). When the open limit switch 6b is turned on (point e) (YES in S15), the solenoid valve 2 is opened (point f) (S16). As a result, purge air is injected into the slit 14 (g point) to remove the accumulated ash. Next, the predetermined time t2 is counted (S17), and the air drive unit 10 is controlled to stop the gate disk 7 (point h) (S18). Here, the predetermined time t2 may be zero. In this state, the opening of the gate disk 7 is completed, and purge air is continuously injected into the slits 13 and 14.

Next, when the control unit 5 determines to close the gate disk 7, the air drive unit 10 is controlled to close the gate disk 7 (point i) (YES in S19). Then, it is monitored whether the open limit switch 6b is turned off (S20). When the open limit switch 6b is turned off (point j) (YES in S20), the solenoid valve 2 is closed (point k) and the purge air is stopped. (S21). In this state, since the gate disk 7 continues the closing operation, the control unit 5 monitors whether the closing limit switch 6a is turned on (S22). When the closing limit switch 6a is turned on (point l), the closing operation of the gate disk 7 is stopped (point m) (S23). Thereafter, when the control unit 5 determines to release the gate disk 7 (YES in S24), the process returns to step S11 and is repeated.
That is, when the opening of the gate disk 7 is started, ash enters the slit 13 on the distal end side of the gate disk 7 from the gap of the gate disk 7 (see FIG. 3A). In addition, a predetermined time is required until the gate disk 7 passes through the slit 14 on the terminal side of the gate disk 7. Therefore, in the present invention, when the gate disk 7 passes through the slit 13 at the front end side of the gate disk 7, purge air is jetted for a predetermined time at that time (see S14). Since the purge air has a high pressure in the first injection, the ash removal capability is high.
When the open limit switch 6b detects that the gate disk 7 has been opened, the purge air is continuously supplied again. Thereby, the ash deposited on the slit 13 on the front end side of the gate disk 7 can be efficiently removed.
The gate disk 7 has a predetermined length and requires a predetermined time to open and close. That is, when a closed limit switch 6a for detecting that the gate disk 7 is closed at a predetermined position and an open limit switch 6b for detecting that the gate disk 7 is opened at a predetermined position are provided. Assuming that the closed limit switch 6a is ON when 7 is closed at a predetermined position, the fact that the closed limit switch 6a is turned OFF from the ON state indicates that the gate disk 7 has moved in the opening direction. I can lose weight. That is, it can be regarded as the start of opening. Thereby, the moving direction of the gate disk 7 can be detected from the two states (ON / OFF) of each switch.

FIG. 8 is a view showing an embodiment of the ash conveying pipe using the purge air control device of the present invention. In this embodiment, the raw powder 21 is switched from the recovered raw powder silo 20 to the pier side 33 and the sea sand side 29, and the case where the purge air control device of the present invention is attached to the pipe 31 on the sea sand side 29 will be described. To do. In the middle of the pipe 31 on the sea sand side 29, the air cylinder 22 opens and closes the gate disk 23 to convey the raw powder 24 to the flow path or stop it. Since the tube 31 is disposed obliquely, the raw powder is easily deposited in the slit 25 formed in the middle of the tube 31. Therefore, an injection port is provided in the slit 25 and is connected from the control air 30 via the main valve 27 and the electromagnetic valve 26.
With this configuration, when the gate disk 23 is opened, the solenoid valve 26 is opened so that purge air is injected from the injection port. Further, when the gate disk 23 is closed, the electromagnetic valve 26 is closed so that purge air is not injected from the injection port. Although the limit switch is not shown in the figure, it goes without saying that the gate disk 23 is provided with a limit switch as shown in FIG. 1 and the gate disk 23 and the electromagnetic valve 26 are controlled based on the signal.

It is a schematic diagram for demonstrating the state which the purge air control apparatus of this invention closed the gate disk. It is a schematic diagram for demonstrating the state which the purge air control apparatus of this invention open | released the gate disk. (A) is a figure which shows a flow path when the front-end | tip of the gate disk 7 slips out from the slit 13, (b) is a figure which shows a flow path when the front-end | tip of the gate disk 7 slips out from the slit 14. It is a flowchart explaining operation | movement of the purge air control apparatus which concerns on the 1st Embodiment of this invention. 5 is a timing chart of each unit corresponding to the flowchart of FIG. 4. It is a flowchart explaining operation | movement of the purge air control apparatus which concerns on the 2nd Embodiment of this invention. It is a timing chart of each part corresponding to the flowchart of FIG. It is a figure which shows the Example of the ash conveyance piping using the purge air control apparatus of this invention. It is a figure explaining the problem in the conventional purge air control apparatus.

Explanation of symbols

  1 Purge air supply source, 2 Solenoid valve, 3 Ash transfer piping, 4 Ash, 5 Control unit, 6 Limit switch, 7 Gate disk, 8 Striker, 9 Air cylinder, 10 Air drive unit, 11, 12 Seal member, 13, 14 Slit, 15, 16 tube

Claims (6)

Ash deposited in the slit between the ash transport pipe provided in the middle of the ash transport pipe for transporting the ash generated from the flue gas desulfurization apparatus and opening and closing the flow path of the ash transport pipe Purge air control device for removing
A purge air supply source for supplying purge air to the slit; a control valve for supplying or stopping purge air from the purge air supply source; a gate driving means for opening and closing the gate disk; and the control valve and the gate driving means. A control unit for controlling,
The said control part controls the said control valve so that the said purge air may be supplied to the said slit when the said gate disk is an open state, The purge air control apparatus characterized by the above-mentioned. It has a limit switch that detects the open / closed state of the gate disk,
The control unit controls the control valve to supply the purge air when the limit switch detects the opening of the gate disk, and controls the control valve to detect the closing of the gate disk when the limit switch detects the closing of the gate disk. The purge air control device according to claim 1, wherein the purge air is stopped.   The control unit controls the control valve to supply the purge air for a predetermined time when the limit switch detects the opening start of the gate disk, and again when the limit switch detects the opening completion of the gate disk. The purge air control device according to claim 1 or 2, wherein the purge air is continuously supplied by controlling the control valve. The limit switch comprises a closed limit switch for detecting that the gate disk has been closed, and an open limit switch for detecting that the gate disk has been opened.
4. The purge air control device according to claim 2, wherein the closing limit switch is regarded as a start of opening of the gate disk due to a change from a state in which the closing completion of the gate disk is detected to a different state. .   The purge air control device according to any one of claims 1 to 3, wherein the control valve is configured by an electromagnetic valve that opens and closes the valve depending on the presence or absence of an electric current.   2. The purge air control device according to claim 1, wherein the gate driving means is constituted by an air cylinder driven by air force.

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