JPS59229112A - Premixture combustion device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of backfire and to increase a turn down ratio, by a method wherein the air ratio of air-fuel mixture of gas fuel and the air is varied depending upon a combustion load. CONSTITUTION:Gas fuel from a line 1 is mixed with the air for combustion, flowing through a line 3 by means of an ON-OFF valve 28 and a govenor 2, with the aid of a mixer 4. The air-fuel mixture is fed to a burner 6 from a pump 5 consisting of a reproduction pump and the like. By setting the pressure of gas fuel at a value higher than the atmosphere pressure by means of the governor 2, characteristic indicated by a line l1 is obtained. By decreasing the pressure of the gas fuel over the atmosphere pressure by means of the governor 2, characteristic of a line l2 is obtained. This permits prevention of the occurrence of backfire and causes increasing of a turn down ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a premix combustion device. Although the premix combustion device has advantages such as simple piping and high flame stability, it has the problem of causing flashback and being unable to maintain a large turndown ratio.

An object of the present invention is to provide a premix combustion device that can prevent the risk of flashback and increase the turndown ratio.

FIG. 1 is a system diagram of one embodiment of Honwamei. Gaseous fuel flows from pipe 1 through on-off valve 28 and governor 2 to pipe 8.
It is mixed in the mixer 4 with the combustion air from the air. This mixed gas is guided to the burner 6 from a pump 5, which is a regeneration pump or the like. The structure of the burner 6 is shown in FIG. 2, and has a cylindrical shape.
A flame stabilizing member 8 having a flame stabilizing hole 7 at its tip is provided.

The relationship between the air ratio of the mixed gas supplied to the burner 6 and the combustion load will be explained with reference to FIG. When the pressure of the gas fuel is set higher than the atmospheric pressure by the governor 2, the characteristics shown by the line nl are obtained. Further, when the pressure of this gas fuel is also reduced by the atmospheric pressure F by the governor 2, the characteristics of the line 12 are obtained. Combustion in the burner 6 can be carried out in the range w1 of the air ratio ml y rn Q. Line 11. In any of the characteristics of β2, in a low flow velocity range of the mixed gas where there is a risk of flashback, the mixture gas deviates from the combustion range Wl, thereby making it possible to prevent flashback.

FIG. 4 is a system diagram of an embodiment of the pond of the present invention.

Corresponding parts of the previous embodiments are given the same reference numerals.

In the characteristic shown by line 11, combustion can be performed by burner 9 outside the combustion range W1 of burner 6. The burner 9 burns an inner cylinder 10 and an outer cylinder 11. The inner cylinder 10 has a flame stabilizing member 12, and a mixed gas is supplied to this cylinder 10 from the pump 5. Air is supplied to the space 1B between the inner cylinder 10 and the outer cylinder 11 via a conduit 15 from a pump 14 such as a regeneration pump.

FIG. 5 is a system diagram of a further embodiment of the present invention. Corresponding parts of the embodiment described above are given the same reference numerals.

In this embodiment, the burner 16 can carry out combustion even in the combustion range Wl of the burner 6 described above and outside it, with the characteristic shown by the line β2 in FIG. This burner 16 includes an inner cylinder 17 and an outer cylinder 18.

A flame stabilizing member 19 is provided in the inner cylinder 17, and a mixed gas is supplied from the pump 5 into the inner cylinder 17. Inner cylinder 1
Gas fuel is pumped into the space 20 between the outer cylinder 7 and the outer cylinder 18 via a pipe line 21.

FIG. 6 is a system diagram of an embodiment of the present invention.

This embodiment is similar to FIG. 5, and corresponding parts have the same reference numerals. In this embodiment as well, it is possible to carry out combustion using the burner 22 both inside and outside the combustion range W1 of the burner 6 with the characteristics shown by the line 12. Gaseous fuel is fed under pressure to the pipe body 23 of the burner 22 from a pipe line 24 . Mixed gas is supplied from the pump 5 to a cylindrical body 25 surrounding the tube body 23 . This cylindrical body 25 has
A flame stabilizing member 26 is provided.

FIG. 7 shows an improved structure in which the pumps 5 and 14 shown in FIG. 4 are combined into one.

The impellers 119, 120 of the pumps 5 and 14 are fixed to a common drive shaft 118 and housed in a casing 128. The casing 128 has a substantially cylindrical shape Fy.
, and side covers 125 and 126 fixed to both ends of the main body portion 124.

At a central position along the axis within the body portion 124 is a drive shaft 1.
A partition wall 127 perpendicular to 18 is fixedly provided. In this way, the main part 124 and both side covers 125
Inside the casing 12B configured with = 126, there is a pair of spaces 148.
144 is formed. Both end surfaces of both impellers 119 and 120, side covers 125 and 126, and partition wall 127
The gap between them is made extremely small.

The outer peripheral edges of the site covers 125 and 126 are configured to bulge in opposite directions, and the bulges 128,
129 connection port 14'l, 142 has conduit 168.17
8 are connected respectively. The bulges 128 and 129 are formed around the entire axis 9 of the drive shaft 118. Connecting ports 139° and 140 are formed at the lower ends of the bulging portions 128 and 129 in FIG. be done. These ventilation passages 121, 122 are connected to the drive shaft l18.
are formed in mutually shifted angular ranges along the direction of rotation. Grooves 180 and 181 facing each ventilation passage 121 and 122 are formed on the outer peripheral edge of both impellers 119 and 120, separated from each other.
It is divided into a plurality of parts along the circumferential direction by partition plates 182 and 188 that lie within a plane that includes the axis of No. 8.

Rotation bearings 184 and 185 are provided at the center of the partition wall 127 and the side cover 126, and the drive shaft 118 passes through the partition wall 127 and the side cover 126 via the rotation bearings 184 and 185. Furthermore, casing 1
A rotational and thrust bearing 186 is provided at the center of the side cover 125 in 2a, and the end of the drive shaft 118 is received by this bearing 136. ,
It is directly connected to the output shaft Ja8 of the motor 137. Therefore, by driving the motor 137, the drive shaft 118 is rotationally driven. Note that the drive shaft 118 and the output shaft 138 of the motor 137 may be connected via a pulley, an endless belt, or a transmission means such as a gear. In this way, the pump 5 is configured in one part (the left side in FIG. 7) of the casing 123 that includes the ventilation passage 121, and the pump 14 is configured in the oil side part (the seventh part) of the casing 12B that includes the ventilation passage 122. (right side of the figure).

In such pumps 5 and 14, the mixed gas from the mixer 4 is sucked through the connection port 139 by the pump 5, compressed in the ventilation passage 1' 21, and then supplied to the inner cylinder 10 from the connection port 141. . In the pump 14, secondary air for combustion at atmospheric pressure is sucked through the connection port 140 and passed through the ventilation passage 122.
After being compressed inside, it is supplied to the outer cylinder 11 from the connection port 142 via the conduit 15.

In this way, high supply pressures can be obtained with the skewer pump. In the ventilation passages 121 and 122, heat is generated due to the compression of the mixed gas and the secondary air for combustion, but since these ventilation passages 121 and 122 are formed on mutually opposite sides of the casing 123, The heat dissipation from the surface is achieved smoothly, and the ventilation passages 121 and 122 are efficiently cooled.

FIG. 8 is a cross-sectional view of an embodiment of the pond of the present invention.

In the embodiment described above, the regeneration pump 5, 14 is driven by the motor 18.
In the pond embodiment of the present invention, the regeneration pump has casings 146, 147 attached to both ends of the motor 187 (left and right ends in FIG. 8). may be attached. Casing 1
46 and 147 include mutually opposing main body portions 148 and 149 that are substantially cylindrical with a bottom, and side covers 150 and 151 that are fixed to mutually separated sides of the main body portions 148 and 149, respectively. Therefore, the pump 5 is configured within the casing 46 and the pump 14 is configured within the casing 4
Constructed within 7. The regeneration pump is constructed similarly to the regeneration pump of the previous embodiment, with the pump 5.14 having a reservoir formed at both ends of the motor 187.

As described above, according to the present invention, since the air ratio of the gas mixture of gas fuel and air is changed according to the combustion load, flashback can be prevented and the turndown ratio can be increased. You can take it. Also, when the air ratio of the mixed gas is reduced as the combustion load decreases, air is separately supplied to the burner, and when the air ratio of the mixed gas is increased as the combustion load is reduced, gas fuel is separately supplied to the burner. This makes it possible to increase the turndown ratio and perform combustion.

[Brief explanation of drawings]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a sectional view showing the structure of the burner 6 of the embodiment shown in Fig. 1, and Fig. 3 shows the relationship between combustion load and air ratio. FIG. 4 is a system diagram of an embodiment of a pond according to the present invention, FIG. 5 is a system diagram of an embodiment of a pond according to the present invention, and FIG. 6 is a system diagram of an embodiment of a pond according to the present invention. FIGS. 7 and 8 are sectional views respectively showing the single component configuration of the pump 5.14 in the embodiment shown in FIG. 4...Mixer, 5,14...Pump, 6.9.16
゜22... Barna's agent Patent attorney Kei Nishikyo Department Part 1- Figure 2 Figure 3 +)'&'

Claims (3)

[Claims] (1) A premix combustion device characterized by supplying a mixed gas of gas fuel and air, the air-fuel ratio of which is changed according to the combustion load, to Sugi, No(-su). (2) A premix combustion device characterized by reducing the air ratio of a mixed gas of gas fuel and air as the combustion load decreases, and supplying this mixed gas and air to a burner. (3) A premix combustion device characterized in that the air ratio of a mixed gas of gas fuel and air is increased as the combustion load decreases, and the mixed gas and gas fuel are supplied to a burner.