JPH05677Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a structure for supplying air and gas mixture air to the burner of a furnace, and in particular to a gas flue that supplies gas to a gas mixing device and a gas mixing device. Regarding the wind duct structure of the furnace that streamlines the connection with the furnace.

[Conventional technology]

A wind duct system that supplies low-NOx combustion air to the burners of a furnace is generally configured as shown in FIG. 9. In the figure, air supplied by a high-pressure fan 1 is heated by an air preheater 2, passes through a secondary air passage 3, and is branched into an over air port 5 and a burner 6 provided in a furnace 4. Air for the burner 6 is fed to a wind box 7 provided in the furnace 4, and a gas flue 8 is connected to the secondary air duct 3 upstream of the wind box 7. A gas mixing device 9 is installed in the section,
Air fed from the secondary air passage 3 and gas fed from the gas flue 8 are mixed by this gas mixing device 9, and the mixed gas air is sent to the burner 6. Note that the reference numeral 10 in the figure is a ventilator for recirculating exhaust gas discharged from the furnace 4 to the bottom of the furnace 4.

The connection between the secondary air duct 3 and the gas flue 8 has conventionally been constructed as shown in FIGS. 5 to 8. That is, the secondary air passage 3 is divided into upper and lower parts by a partition plate 11, with the upper part serving as an air passage 12 communicating with the over air port 5, and the lower part serving as a gas mixed air passage 13 communicating with the wind box 7. There is. Inside this secondary air passage 3 is the partition plate 1.
1, three tubular gas mixing devices 9 each having a streamlined cross section are provided.
A plurality of gas outlet ports 14 opening inward are formed. The upper end of this mixing device 9 opens on the upper surface of the air flow path 12 and is connected to one end of the upper and lower branched upper part of the gas flue 8 via an inlet flue 15. On the other hand, one end of the lower side of the gas flue 8 is
It is connected to an opening formed on the lower surface of the gas mixing air flow path 13 of the mixing device 9 . The gas supplied from the gas flue 8 is fed into the mixing device 9 from above and below, enters the gas mixing air channel 13 via the gas outlet 14, is mixed with air, and is supplied to the wind box 7. . In addition, the reason why the cross-sectional shape of the mixing device 9 is streamlined is that it also serves as a flow rate measurement, and for this reason, the sides of the secondary air passage 3 in front and behind the part where the mixing device 9 is installed are formed with long straight parts. has been done. As a result, the connecting portions between the gas flue 8 and the mixing device 9 are provided above and below the secondary air duct 3, and a large space is required in the vertical direction of the connecting portions.

[Problem that the invention attempts to solve]

As mentioned above, in the conventional furnace air duct structure, the connection between the secondary air duct and the gas flue requires a large space in the vertical direction, and consideration must be given to downsizing the furnace equipment such as ducts. The problem was that the height of the furnace was unnecessarily high.

The present invention has developed a furnace air duct structure that can reduce the installation space of the secondary air duct and keep the height of the furnace low, without impairing the furnace performance such as gas mixing performance, flow rate measurement accuracy, or pressure loss value. The purpose is to provide.

[Means for solving problems]

In order to achieve the above object, the present invention has an air passage which is divided into upper and lower halves by a partition plate and has an air passage in the upper part and a gas mixed air passage in the lower part, and is connected to the gas mixed air passage. A furnace air duct consisting of a gas mixing device formed into a tubular shape with a streamlined cross section and a gas outlet, and a gas flue connected to the upper and lower end openings of the gas mixing device to supply gas. The structure is such that a mixer inlet flue is provided in the air flow path, communicating with the upper end opening of the gas mixer and connecting to the gas flue.

[Effect]

According to the present invention, the position where the gas flue is connected to the gas mixing device is inside the air flow path and on the side and bottom of the air duct, so the height of the air duct can be lowered and the installation space for the air duct can be reduced. can be made smaller. Furthermore, by providing a rectifying plate at the connection part in the air flow path between the gas flue and the gas mixing device,
The increase in pressure loss in the air flow path can be suppressed, and even if the height of the furnace is lowered, the performance of the furnace will not deteriorate.

〔Example〕

Hereinafter, an embodiment of a furnace air duct structure according to the present invention will be described with reference to the drawings.

An embodiment of the present invention is shown in FIGS. 1 to 4.
In these figures, the same or equivalent parts as in the conventional example shown in FIGS. 5 to 8 are denoted by the same reference numerals, and the explanation thereof will be omitted. The feature of this embodiment is the connection structure between the upper end of the gas flue 8 and the upper end of the gas mixing device 9, and other parts are the same as the conventional example. The upper end of the gas mixing device 9 is airtightly connected to the lower surface of the partition plate 11, and an opening 11a communicating with the gas mixing device 9 is formed in this portion of the partition plate 11. A mixer inlet flue 15 is provided in the air flow path 12 on the upper surface of the partition plate 11 so as to cover the opening 11a, and one end of this flue 15 is connected to the upper end of the gas flue 8. connected, and the other end is sealed. The lower end of the gas mixing device 9 is connected to the branched lower side of the gas flue 8, as is conventional. That is, the gas fed from the gas flue 8 enters the mixer inlet flue 15 and enters the gas mixer 9 through the opening 11a formed in the partition plate 11.
The gas is supplied from the upper end to the gas, and further enters the gas mixing air flow path 13 via the gas outlet 14 to be mixed with air. Further, on both sides of the mixing device inlet flue 15 in the air flow path 12 in a direction perpendicular to the air flow direction, a rectifying plate 16 having a slope formed between it and the partition plate 11 is provided.

According to this embodiment, the mixing device inlet flue 15 is
By providing it in the air flow path 12 of the next air passage 3,
There is no convex part at the top of the secondary air duct 3, and the vertical installation space for installing the secondary air duct 3 is approximately 1.5 m.
This makes it possible to reduce the height of the steel frame and duct indicator around the furnace 4.

Moreover, the pressure loss in the air flow path 12 due to the installation of the mixing device inlet flue 15 can be reduced by providing a rectifying plate 16 before and after the mixing device inlet flue 15 in the air flow direction. The pressure loss can be kept within the pressure loss (approximately 5 mmAg) that would otherwise occur. Further, the cross-sectional reduction ratio of the air flow path 12 can be kept small by changing the rectangular ratio and lowering the height without changing the cross-sectional area of the mixer inlet flue 15.

[Effect of idea]

As described above, according to the present invention, the height of the air duct can be reduced by providing the mixing device inlet flue within the air flow path that constitutes the air duct of the furnace.
The installation space for the wind duct can be reduced.
As a result, the height of the furnace can be lowered, making it easier to arrange surrounding piping, etc.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a wind duct gas mixing section according to an embodiment of the furnace air duct structure according to the present invention;
3 and 4 are a plan view, a front view, and a side view of FIG. 1, respectively, FIG. 5 is a perspective view showing a conventional air duct gas mixing section, and FIGS. 6, 7, and 8 are FIG. 5 is a plan view, a front view, and a side view, respectively, and FIG. 9 is a configuration diagram showing a fluid path of a flue duct of a furnace. 3...Wind duct, 4...Furnace, 8...Gas flue, 9
... Gas mixing device, 11 ... Partition plate, 12 ... Air flow path, 13 ... Gas mixing air flow path, 14 ... Gas outlet, 15 ... Mixing device inlet flue, 16 ...
rectifier.

Claims (1)

[Claims for Utility Model Registration] (1) An air duct that is divided into upper and lower halves by a partition plate and has an air passageway in the upper part and a gas mixture air passageway in the lower part, and communicates with the gas mixture air passageway. A furnace air duct consisting of a gas mixing device formed into a tubular shape with a streamlined cross section and a gas outlet, and a gas flue connected to the upper and lower end openings of the gas mixing device to supply gas. An air duct structure for a furnace, characterized in that a mixing device inlet flue communicating with the upper end opening of the gas mixing device and connected to the gas flue is provided in the air flow path. (2) The air duct structure for a furnace according to claim 1, wherein the flue at the entrance of the mixing device provided in the air flow path is covered with a rectifying plate.