JPS62238922A - Combustion control device - Google Patents

Abstract

PURPOSE:To sense an abnormal combustion state and enable a combustion to be restricted by a method wherein a temperature of a flame holding wall is detected to control a combustion by a burner. CONSTITUTION:A combustion plate 4 having a small group of flame ports G is placed in a flange 12 of a mixing box 14 and a refractory frame 43 acting as a flame holding wall is fitted outwardly to an outer peripheral edge of the combustion plate 4. A thermal sensitive element Th comprised of a bimetal is buried between a projecting part 43a formed at an upper end of the refractory frame 43 and the combustion plate 4. The thermal sensitive element Th is connected to an electromagnetic main valve through a lead wire. Due to this arrangement, if an abnormal combustion occurs, a heat from the flame is transmitted to the thermal sensitive element Th through the flame holding wall to cause the bimetal to be operated to close the main valve. The flame holding wall has a more superior flame holding characteristic due to the projection part 43 and if it shows a hot temperature, a temperature sensing action of the thermal sensitive element Th is made fast. With this arrangement, a fatal accident can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion control device for detecting combustion conditions and controlling combustion.

[Prior Art] In combustion devices such as domestic water heaters, the state of the gas flame is detected by an electrode-type frame, and the air-fuel ratio is detected by a thermocouple-type temperature-sensitive member. Safety is ensured against abnormal combustion.

[Problems to be solved by the invention] In this way, safety has been attempted, but since unstable thermofluid is used as fuel, in recent years, it has become necessary to prepare for the unlikely event of a malfunction. It is hoped that a device that will further enhance safety will be developed.

This invention is a combustion control device that has been created with a lot of ingenuity to meet these expectations, and has the advantage of being able to avoid situations related to abnormal combustion even in the unlikely event of a breakdown, further reinforcing safety. The purpose is to achieve the desired effect.

[Means for Solving the Problems] In order to achieve the above object, the combustion control device of the present invention, in an all primary air combustion type burner having a flame stabilizing wall and equipped with eight nozzles, controls the temperature of the flame stabilizing wall. The system employs a configuration that is characterized by detecting and controlling the combustion of the burner.

[Operation and Effects of the Invention] The combustion control device of the present invention detects the temperature of the flame-holding wall and controls the combustion of the burner. This is advantageous from a safety standpoint.

[Example 1] Figures 1 and 2 show an instantaneous gas water heater incorporating the combustion device of the present invention.

This instantaneous gas boiler includes a combustion box 10 whose interior is a combustion chamber, a forced-air gas combustion device (burner) 1 of an all-primary air combustion type that performs complete combustion only with secondary air, and a combustion box 10.
A heat exchanger equipped with a plate fin group 21 arranged at the upper part of the combustion box and having both ends welded to both walls of the combustion box, a combustion box 10 and a burner 1 are housed, and an outside air inlet 31 is provided at the lower part of the side wall. It includes a water heater case 3 and a control device 5 for a burner 1.

The combustion box 1o has an exhaust port 1 at the upper end that communicates with an exhaust pipe 11.
A mixing box 14, which is provided with 0A and whose lower end is open and whose interior is a mixing chamber 1A for fuel gas and air, is provided so as to close the lower end opening. A ceramic combustion plate 4 having a group of small nozzles G is placed on a flange 12 formed at the upper end of the mixing box 14.

The mixing box 14 is equipped with a blower 13 for supplying air and a gas vibrator 17 having an injection port 15, which constitutes the burner 1 described above.

In this embodiment, the small crater group G of the combustion plate 4 has holes of different diameters, and the frequency of vibration generated in each hole during combustion is dispersed to prevent resonance and reduce noise. . The combustion plate 4 is attached as follows. In other words, the ceramic fireproof frame 43 as a flame-holding wall is used as the combustion plate 4.
is fitted around the outer periphery of the The upper end of this refractory frame 43 forms a projecting portion 43a oriented toward the center. Furthermore, a frame-shaped fixture 45 is fitted onto the outside of the fireproof frame 43, and a flange 45G formed thereon is sandwiched between the flange 10B of the combustion box 1o and the flange 12 of the mixing box 14. A heat-sensitive element Fh made of bimetal, for example, is entirely buried in a portion located between the projecting portion 43a of the fireproof frame 43 and the combustion plate 4. This heat-sensitive element Th is connected to an electromagnetic main valve (not shown) via a lead wire. Therefore, when an accident such as abnormal combustion occurs, the heat from the flame is transmitted to the heat-sensitive element Th through the flame-holding wall, and the bimetal is activated to open the main valve. Such abnormal combustion can also be detected later by the frame rod 6 and the temperature sensing member 59, but in the event that both the frame rod 6 and the temperature sensing member 59 break down for some reason. Even if it is assumed that is negative, serious accidents can be avoided by using the heat sensitive element Th. This, so to speak, ensures safety in two stages, and safety is further reinforced. At this point, the humidity of the projecting portion 43a of the flame-holding wall has actually increased from 700 degrees Celsius in normal conditions to 750 to 800 degrees Celsius in abnormal conditions, while the heat-sensitive element Th of the flame-holding wall is In some parts, the temperature ranges from about 600 degrees Celsius during normal times to 750 to 800 degrees Celsius during abnormal times. For this reason, in the embodiment, it is advantageous in terms of temperature sensing agility that the heat sensitive element Th is arranged in a portion of the flame stabilizing wall that is exposed to a large temperature difference. Further, by providing the projecting portion 438 on the flame stabilizing wall, the flame stabilizing property is improved in that the flame does not spread out and is restrained by the flame stabilizing wall.

Generally, during combustion, the flame-holding wall around the combustion plate 4 is easily affected by temperature increase and is in a high temperature state. In addition, the flame-holding property of the flame-holding wall is improved due to the protruding portion 43a, and the heat-retaining property of the flame-holding wall is further improved.

This is why the temperature raising effect and the heat retention effect are synergistic, and the flame stabilizing wall reaches a high temperature as shown in the above-mentioned value, and the heat sensitive element Th becomes sensitive in terms of temperature sensing.

Furthermore, since the surface of the projecting portion 43a that faces the flame has a gently curved shape, it not only has the effect of reinforcing the flame-holding wall, but also allows the projecting portion to form a right angle during molding. In contrast, it is easier to mold, and the flow of thermal fluid is smoother, which is advantageous in terms of thermal efficiency. Further, as the flow of the thermal fluid becomes smoother, the noise generated due to the flow is suppressed.

On the other hand, the control device 55 has a pair of electric lights installed on the upper surface of the combustion plate 4 in order to detect the presence or absence of flame in the combustion device 1. i
A frame consisting of 6a and 6b [l Rad 6, a safety valve 51 and a flow control valve 53, two two-pole sparkers 55 and 57 which are igniters provided on the upper surface of the combustion plate 4, and the safety valve 51, rumor Control valve 53, ignition device 55.57
and a control circuit 50 that controls the motor M of the blower 13 and generates an output that automatically closes the safety valve 51 when the frame rod 6 detects a misfire or ignition error.
Equipped with.

Roughly speaking, a through hole 58 is formed in the center of the combustion plate 4 and extends vertically through the hole 58, and a temperature sensing member 59 made of a thermal lightning pair is installed in the through hole 58. For this purpose, the temperature sensing member 59 senses the temperature state of the flame and appropriately adjusts the opening and closing conditions of the air intake to maintain a predetermined air-fuel ratio.

3 and 4 show two other embodiments, -
As an example, as shown in Fig. 3, the heat-sensitive element Th has a heat-conducting part TC made of metal or the like at one end, and one end of this heat-conducting part TC forms the flame-holding wall, its peripheral surface, and the road surface. It is buried in this manner and exposed to the combustion plate 4.

In the remaining example, as shown in FIG. 4, in the heat-sensitive element Th, an ε1-shaped probing portion P protrudes in the direction of the combustion plate 4 from the heat conducting portion Tc embedded in the flame-holding wall.

In this way, the sacrifice of flame stabilization of the flame stabilizing wall can be kept to a minimum compared to the example shown in FIG. It is something. In this case, the probe portion P may also serve as a part of the sparker electrode or frame rod in order to reduce the number of parts.

Incidentally, the small nozzle groups G of the combustion plate 4 are not limited to those with different diameters, but may be composed of ones with the same diameter.

Further, although the fireproof frame 43 is formed separately from the combustion plate 4 in order to improve thermal shock resistance, it is not prohibited to form them integrally. Furthermore, the temperature sensing element Th may be a dish-shaped thermal response plate, a temperature fuse, or a thermistor. In addition, the applicable counter-staining can be implemented with various modifications without departing from the gist of the invention, such as being widely used not only in instantaneous gas water heaters but also in combustion devices in general.

[Brief explanation of drawings]

Figure 1 is a schematic longitudinal sectional view of the whole, Figure 2 is a perspective view of the main parts,
FIG. 3 is a vertical cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 4 is a view corresponding to FIG. 3 showing still another embodiment.

Claims (1)

[Claims] 1. A combustion control device in an all-primary air combustion type burner having a flame-holding wall and a group of craters, characterized in that the combustion of the burner is controlled by detecting the temperature of the flame-holding wall.