JPS6119792Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a gas mixing device installed in a boiler flue or air duct.

A gas mixing device is installed in the wind duct and flue of the boiler to maintain efficient operation according to the load condition of the boiler, and mixes fuel and combustion air and adjusts the flow rate.

FIG. 1 is a schematic vertical cross-sectional view of a conventional gas mixing device, and FIG. 2 is a cross-sectional view taken along the line X--X in FIG. In these figures, 1 is the A gas duct, 2 is the B gas duct, and 3 is the AB mixed gas duct.
These sections are connected in an inverted T-shape. Gases A and B are introduced into ducts 1 and 2, respectively, in the direction of the arrows shown in the figure, and dampers 4 and 5 for adjusting flow rates are provided in the passages, respectively. This damper 4,
Vanes 6 and 7 are rotatably attached to the shaft 5 so as to be perpendicular to the gas inflow direction. The joint part 8 of each duct 1 to 3 is a part where the A and B gases are mixed, and a chamber 9 that communicates with the B gas duct 2 is located in the communication part between the ducts 1 and 3, and is branched from the chamber 9. The nozzle 10 is arranged with its opening facing the duct 3 side.

The conventional gas mixing device configured in this way is
A gas indicated by a broken line arrow is introduced from a duct 1, and a B gas indicated by a solid line arrow is introduced from a duct 2. Then, the A gas is discharged from around the nozzle 10 and the B gas is discharged from the opening of the nozzle 10 and mixed, and the mixed A and B gases are supplied through the duct 3 to a downstream device (not shown), such as a boiler. FIG. 3 is an enlarged view of the Y section in FIG. 1 showing the mixing situation of A gas and B gas.

By the way, in the conventional gas mixing device, the flow rates of both the A and B gases were controlled by dampers 4 and 5 provided upstream of the mixing section 8, that is, in the ducts 1 and 2, respectively. Normally, the dimensions of the opening of the nozzle 10 in the mixing section 8 and the cross section of the space between the nozzles 10 are determined so that the mixing efficiency is optimized at the discharge flow rate of the A and B gases during economical operation of the boiler etc. With conventional flow rate control means, when the flow rate of A gas decreases during intermediate load operation, it is difficult to change the B gas flow rate in proportion to the change. The flow rates of the two gases were inconsistent, resulting in poor mixing of both gases, which adversely affected the performance of downstream equipment.

In addition, since the conventional gas mixing device has dampers 4 and 5 in the ducts 1 and 2,
Since the damper is sized to match the cross section of the ducts 1 and 2, the damper has to be sized to match the cross section of the ducts 1 and 2, resulting in an uneconomical size and the space required to install the damper. He was also having trouble making decisions.

The present invention eliminates these conventional drawbacks and creates a gas that allows both A and B gases to be mixed in an optimal state according to the various operating conditions of the boiler, thereby ensuring the performance of downstream equipment. This was made for the purpose of providing a mixing device.

An embodiment of the present invention will be described in detail below with reference to FIGS. 4 and 5.

FIG. 4 is a schematic vertical cross-sectional view showing one embodiment of the gas mixing device according to the present invention, which corresponds to the conventional FIG. 1, and FIG. 5 is an enlarged view of the Z section in FIG. 4.
In these figures, 1, 2, and 3 are A gas duct, B gas duct, and A and B mixed gas ducts, respectively.As in the past, these are connected in an inverted T-shaped cross section, and ducts 1 and 3 are connected. It is also the same as in the prior art that a chamber (not shown) communicating with the B gas duct 2 is located within the communication portion. The difference from the conventional one is that dampers are not provided in the ducts 1 and 2, and the nozzle 10, which is branched and communicated with the chamber (not shown), extends its opening toward the duct 3 side. At the same time, damper blades 11 are rotatably installed at each opening, and damper blades 12 are also installed at the most downstream side of the passage around the nozzle 10.

The present invention has such a configuration, and by adjusting the opening degrees of the damper blades 11 and 12, the flow velocity of both the A and B gases can be adjusted in any way. That is, the flow rate of A gas changes depending on the load of the boiler, but even when the flow rate of A gas decreases, the opening degree of the damper blade 12 is adjusted to adjust the flow rate of A gas at the discharge part to a desired value. However, in accordance with this, the flow velocity of the B gas discharged from the nozzle 10 can also be made constant by adjusting the damper blade 11. Further, as shown in FIG. 5, in the discharge portions of A gas and B gas, the flow of each gas becomes a very complicated flow, which multiplies the mixing effect.

Therefore, the flow velocity at the discharge portion can be kept constant regardless of any change in the flow rate, and both the A and B gases can be sufficiently mixed to obtain a complete gas mixture. Therefore, it is possible to always make full use of the performance of the downstream equipment.

In addition, since the control device for controlling the operation of the damper blades 11 and 12 can be placed in one place, maintenance is convenient and scaffolding is saved, and the number of blades is significantly reduced compared to conventional dampers. This is extremely advantageous economically, as the weight and capacity of the drive device can be reduced.

As described above, the present invention provides a gas mixing device that is highly effective in practical use.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional view showing a conventional gas mixing device, Fig. 2 is a schematic cross-sectional view taken along the line X-X in Fig. 1,
FIG. 3 is an enlarged view of the Y section in FIG. 1, and FIG. 4 is a schematic vertical cross-sectional view showing an embodiment of the gas mixing device according to the present invention.
FIG. 5 is an enlarged view of the Z section in FIG. 4. 1...A gas duct, 2...B gas duct, 3
... Mixed gas duct, 8 ... Mixing section, 9 ... B gas chamber, 10 ... Nozzle, 11, 12 ... Damper blade.

Claims (1)

[Scope of utility model registration request] A gas mixing device for mixing two types of gas, characterized in that a plurality of nozzles for spraying a second gas are arranged in a duct through which a first gas flows, with their openings facing downstream, and damper blades for opening and closing the flow path are installed at the openings of the nozzles and on the most downstream side between the nozzles.