JP4882170B2 - Inlet air flow detector for pulverized coal machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inlet air flow rate detecting device for a pulverized coal machine used for producing pulverized coal supplied to a pulverized coal fired boiler.
[0002]
[Prior art]
In a pulverized coal fired boiler, a vertical roller mill, a horizontal ball mill, or the like is used as a pulverized coal machine for pulverizing raw coal as a fuel into pulverized coal.
[0003]
As an example of a vertical roller mill, as schematically shown in FIG. 2 (a), a crushing table 5 is disposed in the vertical mill casing 2 and is rotationally driven by a drive motor 3 via a speed reducer 4. Thus, the raw coal 7 introduced through the raw coal input pipe 6 onto the pulverizing table 5 is made up of the pulverizing table 5 and a plurality of pulverizing rollers 8 arranged so as to be pressed onto the pulverizing table 5. On the other hand, an air supply duct 12 equipped with a flow rate adjusting damper 10 and a shut-off damper 11 in order from the upstream is connected to the air chamber 9 formed at the lower position of the crushing table 5. The air (primary air) introduced into the air chamber 9 through the air supply duct 12 is blown into the mill casing 2 through the blowout port 13 opened at a position around the crushing table 5. The pulverized coal 7b finely pulverized on the pulverizing table 5 is conveyed upward and supplied to the pulverized coal fired boiler through the pulverized coal pipe connected to the pulverized coal outlet 14 at the top of the mill casing 2. is there.
[0004]
Since the vertical roller mill 1 having such a configuration requires air at a flow rate corresponding to the mill load, the inlet air flow rate introduced into the air chamber 9 is detected by the air flow rate detection device 15 installed in the air supply duct 12. Based on the detected value, the flow rate adjusting damper 10 is opened and closed to control the air flow to be supplied.
[0005]
As shown in FIG. 2 (b), the air flow rate detection device 15 has a wide portion of a narrowed portion 12a formed at a position downstream of the flow control damper 10 of the air supply duct 12 and below the operation floor 16. The lower ends of the three detection pipes 17 arranged in the vertical direction with a required interval in the width direction are connected to the side plate portion via the draft seats 18 to communicate with the air supply duct 12, and The upper end of the detection pipe 17 is gathered in a detection header pipe 19 horizontally disposed above the operation floor 16, and the detection header pipe 19 is connected to the transmitter 20. The flow rate is detected by taking out air through the detection pipe 17 from a point and taking out the average value in the width direction.
[0006]
[Problems to be solved by the invention]
However, in the case of the conventional flow rate detection device 15 described above, in order to make the pressures in the three detection pipes 17 as uniform as possible, the detection header pipes 19 are arranged horizontally to make the lengths of the three detection pipes 17 equal. If the detection header pipe 19 is placed horizontally, the ash in the air sent through each detection pipe 17 is brought into the detection header pipe 19 and gradually accumulates to block the blockage. The flow rate may not be detected due to blockage. For this reason, it is necessary to periodically discharge the ash, but since the air escapes during operation, it is not possible to perform ash discharge. The fact is that we are cleaning.
[0007]
Therefore, the present invention prevents the detection header pipe from being blocked even if ash accumulates in the detection header pipe, and does not need to stop the operation when the ash is dispensed. Is.
[0008]
[Means for Solving the Problems]
The present invention, in order to solve the above problems, there are connected to the coal pulverizer to carry the pulverized coal to the outside to supply air to the raw coal was pulverized coal pulverizer to pulverized coal The lower ends of a plurality of detection pipes are connected in communication at a plurality of positions perpendicular to the air flow direction in the middle of the air supply duct, and the upper ends of the detection pipes are vertically arranged so that the ash is stored at the lower end. Connected to the position above the ash reservoir of the detection header pipe that is configured to communicate with the transmitter, and the connection position of each detection pipe having the upper end connected to the detection header pipe A stop valve can be opened and closed inside the detection header pipe at a position between the ash reservoir formed on the detection header pipe and a cap can be opened and closed at the lower end of the ash reservoir of the detection header pipe. , Each detection above The ash retrieved by flow deposited on the ash reservoir is brought into the detection header tube together with the air to be detected through the tube, and can be discharged from the lower end of the detection header tube during operation of the coal pulverizer configuration And
[0009]
Since the ash brought into the detection header pipe is stored in the ash reservoir on the lower end side, the detection header pipe is not blocked.
[0010]
Further, the upper portion of the ash reservoir portion formed in the lower end portion of the detection header tube, provided the check valve to be opened and closed, further, since the cap to the lower end of the ash reservoir are an openable and closable provided configuration, stop valve By closing and opening the cap, ash can be dispensed without losing air even during operation of the pulverized coal machine.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIGS. 1A and 1B show an embodiment of the present invention. In the vertical roller mill 1 having the same configuration as the vertical roller mill shown in FIG. A flow rate detection device 21 is installed in which a detection header pipe connected via a detection pipe is placed vertically and an ash accumulation part is provided at the lower end.
[0013]
More specifically, the flow rate detection device 21 is arranged in the width direction on the wide side plate portion of the throttle portion 12a formed at a position downstream of the flow rate adjustment damper 10 of the air supply duct 12 and below the operation floor 16. Three detection pipes 23 having lower ends communicated with each other through a draft seat 24 at a required interval, and upper ends of the three detection pipes 23 are connected to be vertically arranged at an upper position of the operation floor 16 and lower end portions. The detection header pipes 22 are made of ash reservoirs 26, and the detection pipes 23 are bent and arranged so that the air flow can be made uniform, and the lengths thereof are adjusted.
[0014]
The detection header pipe 22 is provided with a stop valve 25 such as a ball valve at a lower end position than the connection position of the detection pipe 23 so that the detection header pipe 22 can be opened and closed from the operation floor 16, and a portion below the stop valve 25 is provided. The ash reservoir 26 is formed and a cap 27 is detachably attached to the lower end. The upper end of the detection header tube 22 is in communication with the transmitter 20.
[0015]
1A and 1B, the same parts as those in FIGS. 2A and 2B are denoted by the same reference numerals.
[0016]
The flow rate detection device 21 having the above configuration is normally used with a cap 27 attached to the lower end of the detection header tube 22 and the stop valve 25 being opened.
[0017]
Thereby, when the vertical roller mill 1 is operated, a part of the air flowing in the air supply duct 12 is taken out into the detection header pipe 22 through the three detection pipes 23. The ash 28 brought into the detection header pipe 22 together with air falls by its own weight, passes through the open stop valve 25, and is stored in the ash storage section 26 at the lower end of the detection header pipe 22. Therefore, the brought-in ash 28 gradually accumulates in the ash reservoir portion 26 at the lower end, but the ash 28 does not collect on the upper side of the detection header 22 serving as an air flow path and is blocked. Therefore, the flow rate detection function can be maintained.
[0018]
Further, when discharging the ash 28 accumulated in the ash reservoir portion 26 of the detection header pipe 22, the stopper 27 is opened after the open stop valve 25 is closed, and the lower end cap 27 is removed so as to be discharged from the lower end. At this time, since the stop valve 25 is closed, air does not leak or escape from the detection header pipe 22. Therefore, the ash removal operation can be performed by closing the stop valve 25 even during the normal operation of the vertical roller mill 1, and it is not necessary to stop the operation.
[0019]
In the above, the detection pipe 23 is longer than the detection pipe 17 shown in FIGS. 2 (A) and 2 (B) due to the vertical placement of the detection header pipe 22, so that the ash 28 is brought in by increasing the pipe resistance. There is an advantage that the amount can be reduced.
[0020]
In the above embodiment, an example of adopting the vertical roller mill 1 to the air supply duct 12 has been described. However, the present invention can be similarly applied to the air supply duct of the horizontal ball mill, and other scopes do not depart from the gist of the invention Of course, various changes can be made.
[0021]
【Effect of the invention】
As described above, according to the inlet air flow rate detection device of the pulverized coal machine of the present invention, air is supplied to the pulverized coal machine that is pulverized into pulverized coal to convey the pulverized coal to the outside. at a plurality of perpendicular to the flow direction of the air at the intermediate position of the air supply duct is connected to the coal pulverizer, each lower end of the plurality of detection pipe communicatively connected, and the upper end of each of the detection pipe, vertical The ash reservoir is formed at the lower end and the upper end is connected to a position higher than the ash reservoir of the detection header pipe that is connected to the transmitter, and the upper end is connected to the detection header pipe. A stop valve is provided in the detection header pipe at a position between the connection position of each detection pipe and the ash reservoir formed on the detection header pipe so as to be openable and closable. Cap at the bottom Assemble the ash that is taken through the detection pipes and is brought into the detection header pipe together with the air whose flow rate is detected, and accumulated in the ash reservoir, during the operation of the pulverized coal machine. The ash brought in by air into the detection header tube can be stored in the ash reservoir, and the detection header tube is not blocked by ash accumulation, and the flow rate is reduced. The detection function can be maintained for a long period of time, the length of the detection pipe can be increased, the pipe resistance can be increased and the carry-in of ash can be reduced, and it can be stopped at the top of the ash reservoir. It provided a valve to be opened and closed, further, since the cap to the lower end of the ash reservoir are an openable and closable provided configuration, even during operation of the coal pulverizer by opening the cap to close the stop valve Payout can be performed in, it exhibits an excellent effect and the like.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an embodiment of an inlet air flow rate detection device for a pulverized coal machine according to the present invention, in which (A) is a schematic view of the whole, and (B) is a view taken in the direction of arrows I-I in (A). It is.
FIG. 2 shows an example of a vertical roller mill. (A) is a schematic diagram of the whole, and (B) is a schematic diagram of a conventional air flow rate detection device as viewed from the II-II direction of (A). is there.
[Explanation of symbols]
1 Vertical roller mill (pulverized coal machine)
7 Coal 7a Pulverized Coal 12 Air Supply Duct 22 Detection Header Pipe 23 Detection Pipe 25 Stop Valve 26 Ash Reservoir 27 Cap

Claims (1)

The flow direction of the air at the intermediate position of the air supply duct is connected to the coal pulverizer for the raw coal was pulverized by supplying air to the coal pulverizer to pulverized coal conveying the pulverized coal to the outside The lower ends of a plurality of detection pipes are connected in communication at a plurality of orthogonal positions, and the upper ends of the detection pipes are vertically arranged to form an ash reservoir at the lower end, and the upper ends communicate with the transmitter. than the ash reservoir of the detection header tube with Te connected to the upper position, further, between a connection position and the ash reservoir portion formed on the detection header pipes of said respective detection pipe connecting the upper end to the detection header pipe A stop valve is provided in the detection header pipe at the position of the position of the detection header so that it can be opened and closed, and a cap is provided at the lower end of the ash reservoir portion of the detection header pipe so as to be opened and closed. The That is brought to the detection header pipe ash deposited on the ash reservoir together with air, pulverized coal, characterized by having the structure can be discharged from the lower end of the detection header tube during operation of the coal pulverizer Machine inlet air flow rate detection device.

Images