JPS60240919A - Combustion device - Google Patents

Abstract

PURPOSE:To enable arbitrary setting of percentage of shut-off O2 in specified gas, by a method wherein a device comprises a flame rod, which is located in the vicinity of a burner port surface, a flame rod, which is located remoter from the burner port surface than the former flame rod, and a resistor which is connected in series to the flame rod positioned in the vicinity of the burner port surface. CONSTITUTION:A resistor 7 is connected in series to a flame rod 5 located in the vicinity of a primary burner port. Meanwhile, A flame rod 6 is located to the upper part of the burner port. The current value of the flame rod 6 is decreased over that of the flame rod 5 during the initial stage, but with the decrease in a percentage of O2, the current value is increased, and after it is increased to a peak value, it is decreased. Meanwhile, the flame rod 5, when it has no resistor connected thereto, has properties as shown by a solid line, and when the resistor is connected in series, the properties is a curved line as shown by a one-dotted line. Thus, a difference in a current value between the flame rod 5 having the resistor and the flame rod 6 is detected. When a difference is decreased to 0 or a negative value, combustion is brought to a stop. This enables arbitrary setting of percentage of the shut-off O2 in specified gas through a change in a resistance value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a safety device for detecting all combustion conditions in a combustion device using gas, oil, etc. as a heat source.

Conventional configurations and their problems Conventional combustion equipment uses sensors such as thermocouples and flame rods as safety devices to detect all combustion conditions, but most of these sensors do not detect levels. For example, a sensor output that is normally 10 μA is used to stop combustion by taking advantage of the fact that the output decreases to 3 μA at abnormal times (for example, at low 02% or incomplete combustion). (Fig. 1) However, when a flame rod is used in a primary burner, etc., the current value of the flame rod is low even under normal conditions, especially when using fuel with a high burning rate, and the current value is only around 1μ8. As shown in Figure 2, in trenches where low 02% decreases to some extent, the flame current value increases, and when it exceeds the -μ peak, the flame current value decreases.
In the case of μA output, if you try to set μAi for cutoff at low 02%, there is a risk of malfunction unless it is set to about 0.5pA, but at this time, cutoff 02% is low at around 15%, and 02% is low. It cannot be cut off at around -18%.

Therefore, there is a method of using two flame rods, one close to the flame hole surface and the other one away from the flame hole surface.In Figure 3, flame rod 1 is installed close to the flame hole surface. ,
The flame rod 2 is installed away from the flame hole surface. The characteristics of the flame current value in this case are as shown in FIG.

Since the flame rod 1 is close to the flame hole surface, the flame current value is relatively large at 02=21% and thereafter shows the curve shown in the figure. On the other hand, flame rod 2 is located away from the flame hole surface, so the flame current value at o2 = 21% is low, but as the oxygen deficiency gradually increases, the flame current value rises, and once the peak is exceeded, the current value increases. descends. At this time, paying attention to the fact that the current values of frame rod 1 and frame rod 2 are reversed, it is possible to interrupt the current value at the point where the current value is reversed. Currently, the cutoff is at 02 17%, but in order to be able to set the cutoff point around 02-18%, the installation position, shape, and combustion condition of the frame rod 1゜2 must be changed. However, the above approach had the disadvantage that it was difficult to adjust between gas types.

j Purpose of the Invention The present invention eliminates all the drawbacks of the prior art, and includes: when reaching low 0% combustion, the room temperature where the combustion device is installed increases;
Another object of this invention is to focus on the phenomenon in which the resistance value increases with temperature rise, and to facilitate correspondence between various gas types, and to be able to arbitrarily set the cutoff o2% for a specific gas.

Structure of the Invention In order to achieve the above object, the combustion apparatus of the present invention includes a flame rod provided near the burner flame hole surface, a flame rod provided farther from the flame hole surface than the flame rod, and a flame rod provided near the burner flame hole surface. It consists of a resistor connected in series to a frame rod installed nearby, and has the effect of making it easy to correspond between various gas types, and allowing the cutoff of 02% for a specific gas to be set arbitrarily. .

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 5 and 6 show the configuration and characteristic diagrams of the combustion device according to the present invention. In FIG. 5, 1 is a burner;
This is an all-fire combustion type burner.

Reference numeral 2 is a secondary combustion chamber for afterburning, and no CO is generated even during combustion at a low 0.2% and when the damper is switched. Normally, it burns in the flame hole 3, but when it becomes low 0.2% due to oxygen deficiency etc., it burns in the secondary flame hole 4. 5 is a flame rod provided near the primary flame hole, and a resistor 7 is connected in series to 5. On the other hand, the number of flame rods provided above the burner flame hole is 6. Said frame rod 5.6 exhibits the characteristics shown in FIG. That is, the current value of the frame rod 6 is initially lower than that of the frame rod 5, but as the current value gradually decreases by 0.2%, the current value increases, and after reaching a peak, the current value decreases. On the other hand, if no resistance is attached to the frame rod 5, the characteristic will be shown by the solid line, and if the resistance is connected in series, the characteristic will be shown by the dashed line.

That is, if a resistor is connected in series to the frame rod 5, 0
The μA at 2-21% is almost the same, but when oxygen is deficient and 02 decreases, the room temperature rises, 1, so the resistance increases as the temperature rises. When connected, the characteristics of the flame rod current value, especially the curve at the time of descent, can be arbitrarily controlled by the resistance value. That is, if a large resistance is applied, the drop will be faster, and if a small resistance is applied, the drop will be slow.

That is, various natural gas called 13A, gas called 6B, 6C, etc. are supplied, and by changing the value of the resistor 7 corresponding to each gas, the cutoff 02% can be set to around 18%. becomes possible. The method of blocking is as follows.

For example, the difference between the current values of the flame rod 5 and the flame rod 6 with the above-mentioned resistance attached is detected, and when the difference becomes O or negative, combustion is stopped. Of course, instead of being O or negative, it may be shut off when the temperature drops to a certain value, for example, 0.2μ.

In addition, in this example, the explanation was given for the full-order burner, but
Other combustion methods such as a Bunsen burner may also be used. That is, in the Bunsen burner, among the curves indicated by the solid line and the dashed-dotted line in FIG. 6, the characteristic of the initial upward curve is simply absent.

7. Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) By changing the resistance value, the 02% cutoff for a specific gas can be set arbitrarily.

(2) For correspondence between each gas type, for example, 6B and 13A
For example, by dividing the resistance into 6B and 13A, it is possible to set the cutoff 02% to around 18% for each gas.

[Brief explanation of drawings]

Figure 1 is a flame rod current value characteristic diagram of a conventional example, Figure 2 is a flame rod current value characteristic diagram of a full-order burner,
FIG. 3 is a configuration diagram using two conventional frame rods, FIG. 4 is a characteristic diagram of two conventional frame rods, FIG. 5 is a configuration diagram of a frame rod according to an embodiment of the present invention, and FIG. The figure shows the characteristics of the same frame rod. 1...burner, 5...flame rod close to the flame hole, 6...flame rod far from the flame hole, 7...resistance. Name of agent: Patent attorney Toshio Nakao and one other person VΔ
-Kuya vote sho 3 ward ward j dimension tsukasa Δ-kuyaku bury 3 Figure 5 to Figure 6 212019 tl tl t 15

Claims (1)

[Claims] A flame rod installed near the primary flame hole surface, a flame rod installed away from the primary flame hole surface, and a resistor connected in series to the flame rod installed near the primary flame hole surface. A combustion device configured to detect combustion based on a difference between a current value provided near the primary flame hole surface and a current value of a flame rod provided away from the primary flame hole surface.