CN215723122U - Vertical coal-fired boiler with changed heat exchange mode - Google Patents
Vertical coal-fired boiler with changed heat exchange mode Download PDFInfo
- Publication number
- CN215723122U CN215723122U CN202122198155.9U CN202122198155U CN215723122U CN 215723122 U CN215723122 U CN 215723122U CN 202122198155 U CN202122198155 U CN 202122198155U CN 215723122 U CN215723122 U CN 215723122U
- Authority
- CN
- China
- Prior art keywords
- heat exchange
- boiler
- smoke chamber
- vertical
- tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The utility model provides a vertical coal-fired boiler with a changed heat exchange mode, which comprises: the vertical furnace body is internally provided with boiler water; the furnace pipe is arranged in the vertical furnace body, the bottom of the furnace pipe is provided with a combustion device, and a feed inlet and an ash outlet are arranged on the furnace pipe and used for generating smoke with heat; the smoke chamber is arranged above the furnace pipe, the air inlet end of the smoke chamber is communicated with the furnace pipe, and the air outlet end of the smoke chamber is connected with the chimney and discharges smoke; the heat exchange tube is provided with the smoke chamber and the heat exchange tube with the fins, smoke enters the smoke chamber to exchange heat with boiler water circulating in the heat exchange tube, and the smoke vertically scours the fin tubes, so that higher heat exchange efficiency can be obtained; the side wall of the smoke chamber is contacted with boiler water, and heat exchange can be carried out similarly, so that the heat exchange efficiency is further improved.
Description
Technical Field
The utility model relates to the technical field of boilers, in particular to a vertical coal-fired boiler shell boiler with a heat exchange mode changed.
Background
The boiler shell boiler is an important industrial boiler product in China. Generally, it means: the fixed pressure-bearing boiler with water as medium and evaporating heating surface mainly arranged in the boiler shell or boiler shell and with boiler furnace (hearth). In a shell boiler, burning flames or flue gas flow in a pipe, and working media flow outside the pipe, and generally, the boiler is a horizontal fire-tube boiler.
A vertical coal-fired boiler is a water tube boiler. The problems that a large number of water pipes need to be arranged in order to improve the heat exchange efficiency, the heat exchange efficiency is low, the evaporation rate per unit area is low, the manufacturing workload is large, pipe holes for the smoke pipes to be filled in need to be drilled in the pipe plates, and the pipe plates are prone to cracking and the like exist.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a vertical coal-fired boiler shell boiler with a changed heat exchange mode, which can improve the heat exchange efficiency;
the utility model provides a vertical coal-fired boiler with a changed heat exchange mode, which comprises:
the vertical furnace body is internally provided with boiler water;
the furnace pipe is arranged in the vertical furnace body, the lower part of the furnace pipe is provided with a combustion device, and a feed inlet and an ash outlet are arranged on the furnace pipe and used for generating smoke with heat;
the smoke chamber is arranged above the furnace pipe, the air inlet end of the smoke chamber is communicated with the furnace pipe, and the air outlet end of the smoke chamber is connected with the chimney and discharges smoke;
the heat exchange tube is a fin tube provided with fins for increasing the heat exchange area on the outer side, a plurality of fin tubes are arranged at intervals and arranged in the smoke chamber, two ends of the heat exchange tube are connected with the smoke chamber and communicated with the outside of the smoke chamber, and boiler water flows in the heat exchange tube.
In a preferred embodiment, one end of the heat exchange tube is provided with a flared opening with the diameter larger than or equal to the diameter of the fins, so that the different-diameter fin tubes with different calibers at two ends are formed, and two opposite side walls of the smoke chamber are respectively provided with mounting holes corresponding to two ends of the heat exchange tube.
In a preferred embodiment, the flare is cylindrical or conical or flat.
In a preferred embodiment, the heat exchange tubes are arranged in an array or staggered arrangement or a combination of the two.
In a preferred embodiment, the heat exchange tubes are arranged perpendicular to the direction of flue gas flow.
In a preferred embodiment, the ash outlet is arranged at the bottom of the furnace pipe and communicated with an ash door arranged on the vertical furnace body, a through hole is formed in the combustion device, and a guide plate which inclines gradually towards the ash outlet is arranged below the combustion device.
In a preferable embodiment, a partition plate used for changing the flow direction of flue gas is arranged in the flue gas chamber, the partition plate divides the flue gas chamber into a process space and a return space, an opening is formed in one end of the partition plate and used for communicating the process space with the return space, the bottom of one end, far away from the opening, of the process space is communicated with the furnace pipe, and one end, far away from the opening, of the return space is communicated with the chimney.
In a preferred embodiment, the heat exchange tube and the partition plate are both vertically arranged, and the chimney is arranged at the top of the smoke chamber and is communicated with the outside of the vertical furnace body.
In a preferred embodiment, the heat exchange tube and the partition plate are both horizontally arranged, and the chimney is arranged at the top of the smoke chamber and is communicated with the outside of the vertical furnace body.
In a preferred embodiment, the heat exchange tube is horizontally arranged, one end of the partition board, which is far away from the opening, is horizontally arranged, one end of the partition board, which is close to the opening, is upwards obliquely arranged, the air outlet end of the smoke chamber is arranged at the lower part of the side wall of the return space, and the chimney is arranged outside the vertical furnace body and is communicated with the air outlet end of the smoke chamber.
According to the technical scheme, the smoke chamber and the heat exchange tube with the fins are arranged, smoke enters the smoke chamber to exchange heat with boiler water circulating in the heat exchange tube, and the smoke vertically scours the fin tubes, so that higher heat exchange efficiency can be obtained; the side wall of the smoke chamber is contacted with boiler water, and heat exchange can be carried out similarly, so that the heat exchange efficiency is further improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic structural view of example 1 of the present invention;
FIG. 2 is a top view of example 1 of the present invention;
FIG. 3 is a schematic structural view of example 2 of the present invention;
FIG. 4 is a schematic structural diagram of embodiment 3 of the present invention;
FIG. 5 is a schematic structural view of a heat exchange tube according to the present invention;
FIG. 6 is an enlarged view of a portion of FIG. 5;
FIG. 7 is a schematic view of the installation of the heat exchange tube of the present invention;
FIG. 8 is a schematic view of an arrangement of heat exchange tubes according to the present invention;
description of reference numerals:
1. a vertical furnace body; 2. a smoking chamber; 3. a furnace pipe; 4. a heat exchange pipe; 5. a chimney; 6. a flue pipe is connected; 7. a furnace door; 8. a grey door; 9. a combustion device; 10. a guide plate; 11. a partition plate; 12. an opening; 13. and (4) flaring.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. Furthermore, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1:
as shown in fig. 1-2 and 5-8, the present invention provides a vertical coal-fired boiler with a changed heat exchange manner, comprising:
the bottom of the vertical furnace body 1 is provided with a base, boiler water is arranged in the base, a water inlet and a steam outlet (water outlet) are arranged on the base, and the base is connected with steam (water) utilization equipment;
the furnace 3 is arranged in the vertical furnace body 1 and horizontally arranged, the lower part of the furnace is provided with a combustion device 9, the combustion device 9 can be a mechanical combustion device such as a fixed grate or a drawing plate jacking grate, the combustion device 9 is provided with a through hole which is a strip-shaped through hole, fuel is placed on the combustion device 9 for combustion, slag leaks from the strip-shaped through hole after full combustion, a space is arranged below the combustion device 9, the fuel is coal, the combustion device 9 is provided with a feed inlet and an ash outlet which are used for generating smoke with heat, the feed inlet is connected with a furnace door 7 arranged on the vertical furnace body 1, and the ash outlet is arranged below the combustion device 9 and used for discharging the slag;
the smoke chamber 2 is arranged in the vertical furnace body 1 and above the furnace pipe 3, the air inlet end of the smoke chamber is communicated with the furnace pipe 3, the air inlet end is communicated with the furnace pipe 3 through a vertically arranged flue connecting pipe 6, and the air outlet end is connected with the chimney 5 and discharges smoke; the fuel is fully combusted in the furnace pipe 3, and heat and smoke generated by combustion enter the smoke chamber 2 to exchange heat with boiler water so as to heat the boiler water;
the heat exchange tube 4 is a fin tube, fins for increasing the heat exchange area are arranged on the outer side of the heat exchange tube 4 and are integrally rolled with the heat exchange tube 4, the fins are arranged on the outer side of the heat exchange tube 4 at intervals, and the extending direction of the fins is vertical to the extending direction of the heat exchange tube 4, so that the heat exchange efficiency is further increased; the boiler water heating device is characterized in that a plurality of pipes are arranged at intervals in the smoke chamber 2, two ends of each pipe are connected with the smoke chamber 2 and communicated with the outside of the smoke chamber 2, boiler water flows through the pipes, boiler water flowing through the heat exchange pipes 4 is heated by smoke in the smoke chamber 2, the design mode of a traditional boiler is changed, the smoke enters the smoke chamber to heat the boiler water positioned on the outer side of the smoke pipe, the smoke enters the smoke chamber 2 to exchange heat with the heat exchange pipes 4 to heat the boiler water positioned in the heat exchange pipes, and the surface area of the boiler water in contact with a heat source is increased; boiler water is divided into a plurality of strands to enter the heat exchange tubes 4, the water with the same volume is divided into a plurality of strands to be heated simultaneously, the heating is faster than the heating by stacking together, and the outer surface of the smoke chamber 2 is also contacted with the boiler water and can also be subjected to heat transfer, so that the heat exchange efficiency is further increased.
One end of the heat exchange tube 4 is provided with a flared opening 13 with the diameter larger than or equal to the diameter of the fins to form a reducing fin tube with different calibers at two ends, and two opposite side walls of the smoke chamber 2 are respectively provided with mounting holes corresponding to two ends of the heat exchange tube 4. Namely, one end of the heat exchange tube 4 corresponds to the diameter of the original heat exchange tube, the other end of the heat exchange tube corresponds to the flaring 13, one end of the heat exchange tube 4 with the original diameter is placed into the smoke chamber 2 from the mounting hole corresponding to the flaring 13 and is connected with the corresponding mounting hole, and the two ends of the heat exchange tube 4 are hermetically connected with the mounting hole. Because the heat exchange tube 4 is externally provided with fins, if an assembly method of the reducing heat exchange tube is not adopted, the upper steel plate of the smoke chamber 2 cannot be welded, the heat exchange tube 4 with the fins is assembled in the smoke chamber 2, and then the upper steel plate of the smoke chamber 2 is assembled, so that a lot of inconvenience is brought, so that the concept of the reducing fin tube is provided, namely, one end of the reducing fin tube is made into a shape with the diameter size of a normal heat exchange tube 4, the other end of the reducing fin tube is made into a shape with the diameter being slightly larger than the outer diameter of the fins (1-2mm), and the flaring 13 is welded with the heat exchange tube.
The flared end 13 has a cylindrical shape or a conical shape or a flat plate shape, and the cylindrical shape or the conical shape is welded to the end of the heat exchange tube 4 and the flat plate shape is welded to the outer side of the heat exchange tube 4.
The heat exchange tubes 4 are arranged in an array or staggered arrangement or the combination of the two. According to the requirements of boiler design on the number of tubes on the convection heating surface of the boiler, the flow rate and the flow direction of flue gas are adjusted, the array flow rate is fastest, and the flow direction is a straight line; the flow speed is slow in the staggered arrangement, the flow direction is the cross flow direction, the retention time of the smoke in the smoke chamber 2 is prolonged, and the heat exchange is sufficient.
The heat exchange tube 4 is arranged perpendicular to the flowing direction of the flue gas. The flue gas longitudinally scours the convection bank to fully utilize the heating surface, thereby improving the thermal efficiency of the boiler and increasing the temperature and the pressure quickly; and is beneficial to water circulation; the pressure bearing capacity of the smoke chamber 2 is improved.
The ash outlet is arranged at the bottom of the furnace pipe 3 and communicated with the ash door 8 arranged on the vertical furnace body 1, the ash outlet is preferably arranged at one side close to the feed inlet, a through hole is formed in the combustion device 9, a side direction is arranged below the combustion device 9, the ash outlet is gradually inclined towards the guide plate 10, the guide plate 10 extends to the bottom of the ash outlet, the guide plate 10 covers the bottom of the lower part of the combustion device 9, the guide plate 10 is inclined towards the ash outlet, one end close to the ash outlet is lower than one end far away from the ash outlet, fuel is combusted on the combustion device 9, the strip-shaped through hole arranged on the combustion device 9 after ash is formed in a combustion mode leaks to the guide plate 10 below, then slides towards the ash outlet along the inclined direction of the guide plate 10, and is discharged from the ash door 8.
Be equipped with the baffle 11 that is used for changing the flue gas flow direction in the smoke chamber 2, the center of the smoke chamber 2 that baffle 11 set up has increased the time that the flue gas dwelled in smoke chamber 2, increases heat exchange efficiency, and baffle 11 is made for heat-resisting material, and baffle 11 separates smoke chamber 2 for process space and return stroke space, and the one end of baffle 11 is equipped with opening 12 and is used for communicateing process space and return stroke space, the one end bottom and the stove courage 3 intercommunication of opening 12 are kept away from to the process space, the one end and the chimney 5 intercommunication of opening 12 are kept away from to the return stroke space. At the moment, the flue gas enters the process space from the furnace pipe 3, then enters the return space through the opening 12, and is discharged out of the vertical furnace body 1 through the chimney 5, so that the three-return boiler is formed.
The heat exchange tubes 4 and the partition plates 11 are both vertically arranged, the chimney 5 is arranged at the top of the smoke chamber 2 and is communicated with the outside of the vertical furnace body 1, and the furnace body is a vertical furnace body, so that the extending direction of the heat exchange tubes 4 is consistent with the extending direction of the vertical furnace body 1, higher heat exchange tubes 4 can be arranged, the volume of boiler water for heat exchange is increased, and the heat exchange efficiency is increased; the partition plate 11 is vertically arranged, the flue gas firstly enters the process space, then flows transversely, enters the return space through the opening 12, flows transversely in the reverse direction, and is discharged from the chimney 5 at the top of one end, and the flowing direction of the flue gas is vertical to the direction of the heat exchange tube 4.
Example 2:
as shown in FIG. 3, the heat exchange tubes 4 and the partition plate 11 are horizontally arranged, and the chimney 5 is arranged on the top of the smoke chamber 2 and communicated with the outside of the vertical furnace body 1. The direction that the heat exchange tube 4 set up makes the flue gas all perpendicular with heat exchange tube 4 when rising and lateral flow, and furthest guarantees heat exchange efficiency.
Example 3:
as shown in fig. 4, the heat exchange tube 4 is horizontally arranged, one end of the partition plate 11 far away from the opening 12 is horizontally arranged, one end close to the opening 12 is upwards obliquely arranged, gaps are arranged between the partition plate and a top plate and side plates of the smoke chamber 2 for smoke to pass through, the air outlet end of the smoke chamber 2 is arranged at the lower part of the side wall of the return space, and the chimney 5 is arranged outside the vertical furnace body 1 and communicated with the air outlet end of the smoke chamber 2. The flue gas enters the process space from the furnace pipe 3, transversely moves upwards firstly, enters the return space through the opening 12, because the partition plate 11 tilts upwards, the smoke chamber 2 starts to enter the return space and then is positioned at the upper part of the return space, transversely moves downwards again, the flue gas with heat originally moves upwards, and the air outlet end of the smoke chamber 2 is arranged at the lower part of the return space, so that the retention time of the flue gas in the smoke chamber 2 can be prolonged, and the heat exchange efficiency is increased.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A vertical coal-fired boiler shell boiler capable of changing a heat exchange mode is characterized by comprising:
the vertical furnace body is internally provided with boiler water;
the furnace pipe is arranged in the vertical furnace body, the lower part of the furnace pipe is provided with a combustion device, and a feed inlet and an ash outlet are arranged on the furnace pipe and used for generating smoke with heat;
the smoke chamber is arranged above the furnace pipe, the air inlet end of the smoke chamber is communicated with the furnace pipe, and the air outlet end of the smoke chamber is connected with the chimney and discharges smoke;
the heat exchange tube is a fin tube provided with fins for increasing the heat exchange area on the outer side, a plurality of fin tubes are arranged at intervals and arranged in the smoke chamber, two ends of the heat exchange tube are connected with the smoke chamber and communicated with the outside of the smoke chamber, and boiler water flows in the heat exchange tube.
2. The vertical coal-fired boiler shell and tube boiler of claim 1, characterized in that one end of the heat exchange tube is provided with a flared opening with a diameter larger than or equal to the diameter of the fins, forming a reducing fin tube with two different end diameters, and two opposite side walls of the smoke chamber are respectively provided with mounting holes corresponding to two ends of the heat exchange tube.
3. The vertical coal-fired shell boiler for changing the heat exchange mode according to claim 2, wherein the flaring is cylindrical or conical or flat.
4. The vertical coal-fired boiler shell and tube boiler of changing the heat exchange mode of claim 1, wherein the heat exchange tubes are arranged in an array or in a staggered arrangement or in a combination of the two.
5. The vertical coal-fired boiler shell and tube boiler of changing the heat exchange mode of claim 1, characterized in that the heat exchange tube is arranged perpendicular to the flow direction of the flue gas.
6. The vertical coal-fired boiler shell and pot boiler capable of changing the heat exchange mode according to claim 1, characterized in that the ash outlet is arranged at the bottom of the furnace and is communicated with an ash door arranged on the vertical boiler body, the combustion device is provided with a through hole, and a guide plate which is gradually inclined towards the ash outlet is arranged below the combustion device.
7. The vertical coal-fired boiler shell and boiler capable of changing the heat exchange mode according to any one of claims 1 to 6, characterized in that a partition plate for changing the flow direction of flue gas is arranged in the flue chamber, the partition plate divides the flue chamber into a process space and a return space, an opening is formed in one end of the partition plate and used for communicating the process space with the return space, the bottom of one end, far away from the opening, of the process space is communicated with the boiler furnace, and the end, far away from the opening, of the return space is communicated with the chimney.
8. The vertical coal-fired boiler shell and tube boiler of change heat transfer mode of claim 7, characterized in that, the heat exchange tube and the baffle all set up vertically, the chimney sets up in the top of smoke chamber and with the outside intercommunication of vertical furnace body.
9. The vertical coal-fired boiler shell and tube boiler of changing the heat exchange mode of claim 7, characterized in that the heat exchange tube and the baffle are both horizontally arranged, and the chimney is arranged on the top of the smoke chamber and is communicated with the outside of the vertical boiler body.
10. The vertical coal-fired boiler shell and boiler with the changed heat exchange mode according to claim 7, characterized in that the heat exchange tube is horizontally arranged, one end of the clapboard, which is far away from the opening, is horizontally arranged, one end of the clapboard, which is close to the opening, is upwards obliquely arranged, the air outlet end of the smoke chamber is arranged at the lower part of the side wall of the return space, and the chimney is arranged outside the vertical boiler body and is communicated with the air outlet end of the smoke chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122198155.9U CN215723122U (en) | 2021-09-10 | 2021-09-10 | Vertical coal-fired boiler with changed heat exchange mode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122198155.9U CN215723122U (en) | 2021-09-10 | 2021-09-10 | Vertical coal-fired boiler with changed heat exchange mode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215723122U true CN215723122U (en) | 2022-02-01 |
Family
ID=80018576
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122198155.9U Active CN215723122U (en) | 2021-09-10 | 2021-09-10 | Vertical coal-fired boiler with changed heat exchange mode |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215723122U (en) |
-
2021
- 2021-09-10 CN CN202122198155.9U patent/CN215723122U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN215723122U (en) | Vertical coal-fired boiler with changed heat exchange mode | |
| CN216010795U (en) | Shell type coal-fired water pipe boiler with changed heat exchange mode | |
| CN216159014U (en) | Vertical oil-gas boiler shell boiler adopting novel heat exchange mode | |
| CN110657414A (en) | Direct-flow steam generator | |
| KR200284927Y1 (en) | High Efficiency Heat Recovery Apparatus | |
| CN215765001U (en) | Shell type oil-gas water pipe boiler adopting novel heat exchange mode | |
| CN113623625A (en) | Vertical oil-gas boiler shell boiler adopting novel heat exchange mode | |
| CN2847050Y (en) | Double boiler tube transverse water coal slurry burning boiler | |
| CN113654020A (en) | Shell type oil-gas water pipe boiler adopting novel heat exchange mode | |
| CN201443861U (en) | Horizontal counter-heating coal-burning atmospheric pressure hot water boiler | |
| CN206320785U (en) | Forced circulation burning coal powder hot-water boiler | |
| CN214009205U (en) | Energy-saving device for coal-fired boiler | |
| CN213578094U (en) | Pipe wall type strong boiler | |
| CN214536856U (en) | Full-premixing water-cooling combustion vacuum boiler | |
| CN212132407U (en) | Biomass boiler structure | |
| CN219955661U (en) | High-efficiency gas hot-blast stove | |
| CN214406486U (en) | Medium-large type non-drum header type integral gas-fired hot water boiler | |
| CN214619472U (en) | Enhanced heat transfer vertical pipe type water-cooling gas steam generator | |
| CN220892206U (en) | Self-contained angular tube steam boiler and heating system thereof | |
| KR102504737B1 (en) | Downward Combustion Apparatus for Solid Fuel | |
| RU200074U1 (en) | HEAT EXCHANGER FOR WATER BOILER | |
| CN208025489U (en) | A kind of full film type wall boiler water wall loop structure | |
| CN211424347U (en) | Steam-driven heat injection boiler | |
| CN106765293A (en) | Forced circulation burning coal powder hot-water boiler | |
| CN216384597U (en) | Heat exchange coil and full-premix condensation wall-mounted furnace heat exchanger using same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |