JPH01123914A - Liquid fuel combustion device - Google Patents

Abstract

PURPOSE:To make the absolute value of an electric current value large, to minimize influences due to the irregularity of the mounted position of a frame rod and the like, and to make it easy to detect a combustion state by forming the frame rod disposed relative to a cylindrical burner body in the form of a ring so as to face the entire area of the circumference of the burner body. CONSTITUTION:With respect to the gaps between a frame rod 13A disposed in the form of a ring and a burner body 2, even if the gap C on one side becomes large due to, for example, the irregularity of a mounted position, the gap D on the opposite side becomes small by the same distance, and accordingly the sum of these gaps, i.e., the value of [C+D], becomes constant. In other words, the mean value of the gaps in a circumferential shape becomes always constant, and hence an ionic current If flowing between the frame rod 13A and the burner body 2 is substantially unaffected by the diversity of the gaps. Also, since the frame rod 13A is disposed in the ring form with respect to the cylindrical burner body 2, the frame rod 13A can correspond with the burner body 2 at the ratio of 1:1 in the circumferential direction of the burner body 2 to enable the ion of flames to be absorbed. Accordingly, no interference of taking in the ion occurs between the frame rod 13A and the burner body 2, and the ionic current If can be obtained most effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to liquid fuel combustion devices such as oil combustors.

Conventional technology In recent years, home heating systems that utilize combustion heat have become more and more user-friendly and more comfortable. Increasingly, air is mixed with indoor air and used for heating purposes as warm air.

An example of a conventional liquid fuel combustion device used in the home heater will be described below with reference to the drawings.

In FIGS. 4 and 5, reference numeral 1 denotes a vaporization cylinder that vaporizes fuel, premixes it with combustion air, and supplies it to a combustion section, and a cylindrical burner body 2 is placed on the top. The burner body 2 is provided with an integrated, narrow-shaped mixing section 3, and a plurality of flame holes 4 on the side wall of the mixing section 3 through which premixed vaporized gas is ejected. Reference numeral 5 denotes a pressure equalizing plate that covers the narrow-shaped mixing section 3 within the burner body 2, and 6 a perforated cylinder stretched tightly against the outer peripheral side wall of the burner body 2, which is made of wire mesh or other porous material. , covering the flame hole 4. Reference numeral 7 denotes a burner cap that closes the upper end opening of the burner body 2, and an inner lid 8 is disposed inside the burner cap to form a heavy lid structure. Here, the perforated cylinder 6 stretched over the outer peripheral side wall of the burner body 2 has its lower end connected to the flange 1a of the vaporizing cylinder 1, and its upper end connected to the burner body 2 by the bent edge 7a of the Pana cap 73 hedge. Closely supported. Reference numeral 9 denotes a sheathed heater for heating the vaporization cylinder 1 to a certain temperature or higher, and is embedded in the upper peripheral wall of the vaporization cylinder 1. Reference numeral 10 denotes an earth ring disposed to cover the premixed gas ejected from the outer periphery of the burner body 2 from below. 1
1 is below the carburetor cylinder 1! A deep dish-shaped burner case that covers and supports the ignition electrode 12 and the flame rod 1.
3 is installed. The ignition electrode 12 and flame iron 13 are insulated from the burner case 11 by covering the mounting portions with insulators 12a and 13a, respectively.

The frame rod 13 is configured such that its tip is bent into a U-shape and opposed to a part of the flame hole 4 of the burner body 2 at a distance, and a DC voltage is applied between it and the burner body 2. be.

In the above configuration, fuel injected into the vaporization cylinder 1 by a pump or the like collides with the wall surface of the vaporization cylinder 1, which is kept at a high temperature by the sheathed heater 9, and is diffused and vaporized. It is premixed with the combustion air sent into 1. This premixed vaporized gas is mixed almost uniformly in the process of passing through the mixing part 3 of the burner body 2 and the small holes of the pressure equalizing plate 6, and is ejected through the flame hole 4 of the burner body 2. When a discharge spark is emitted from the ignition electrode 12 to the ejected premixed vaporized gas, combustion starts, and a flame is formed that closely adheres to the surface of the porous cylinder 6 around the outer periphery of the flame hole 4. Here frame rod 1
When an M current voltage is applied between the burner body 2 and the burner body 2, a minute current flows as shown by the arrow H in FIG. 5 by attracting ions generated in the surrounding flame. Since the sensitivity of this current changes depending on the state of the ions, that is, the state of combustion, ignition, misfire, etc. can be detected by measuring this current.

Among the problems to be solved by the invention, the conventional configuration described above has the following problems. That is, the current direct current obtained by applying a direct current voltage between the frame rod 17 and the burner body 2 is
In addition to the combustion state, the relative position with respect to the flame surface or the distance between the shibana body 2 and the frame rod 13 varies greatly. The gap G between the two is empirically 3 to 4 mm.
They should be kept at least 5 degrees apart, but this distance changes due to variations in installation, deformation over time, etc., and current directivity becomes unstable. Further, the amount of ions generated in the flame increases in the portion where the burning rate is high.

It increases when the flame combustion conditions are the best, near the boundary between the primary and secondary flames, and where the flame volume is large. However, as the combustion speed increases, the flame comes into close contact with the short Shibana body 2, so if the gap G is made large, the flame rod 13 will move away from the flame surface, and the absolute suppression of the current value will be low. Also, the changes will be less.

In particular, in the case of weak combustion with a low combustion load, it is difficult to detect the combustion state by direct current.

For example, if it is determined that the combustion balance has been disrupted and combustion is to be stopped when the current value falls below the calming threshold, the threshold must be set to a value that is lower than the normal end with some margin. However, in the case of the above-mentioned weak combustion, the gap G may vary due to installation variations or change over time, causing early or late disconnection when the combustion state is detected, resulting in C○ and odor. There were problems in that combustion continued even when the combustion balance was disrupted, and combustion stopped even when combustion was in a good range.

As a countermeasure for this problem, if the surface area of the frame rod 13 is made narrow, the ion absorption will be improved. Therefore, if the tip of the frame rod 13 is bent into a U-shape as in this conventional example, or if a plurality of such rods are arranged. However, the nearby frame rod 1
The three comrades competed for ions and interfered, and the positional variations increased, making it less effective.

The present invention solves these conventional problems by applying a DC voltage between the frame rod and the burner body, increasing the absolute resistance to the poor current flow, and reducing the effects of installation variations. This makes detection easier and more reliable.

Means for Solving the Problems In order to solve the above-mentioned problems, the liquid fuel combustion device of the present invention has a frame rod disposed opposite to a cylindrical burner body so as to face the entire circumference of the burner body. It is formed into a ring shape.

7. Effect of the Invention The present invention has the above-described structure, so that the flame rod can effectively absorb ions in the flame without interference, and the absolute value of the current value generated thereby becomes large. In addition, the average value of the gap between the burner body and the frame rod can be kept constant at all times, reducing the effects of installation variations. Therefore, the combustion state can be easily detected with a simple flame rod with a large margin.

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to the drawings.
The same parts as those in the conventional example are denoted by the same reference numerals, and the explanation thereof will be omitted, and only the different parts will be explained.

In FIGS. 1 and 2, 13A is a frame rod disposed around the burner body 2, which is formed into a ring shape, and a conductor 1 disposed on the upper flat part of the burner case 11.
4.15.16 are welded and supported. The above-mentioned conductors 14, 15, 16 have their mounting parts connected to insulators 14a, respectively.
, 15a, and 16a, and is insulated by the burner case 11 and the like. Further, the conductor 14 has its lower end penetrated through the insulator 14a and connected to a controller (not shown), and is configured to apply a DC voltage between the frame rod 13 and the burner body 2. .

Next, a simple equivalent circuit configured to apply this DC voltage will be explained using FIG. 3.

15 is a direct current applied voltage ef applied between the flame rod 13 and the burner body 2, where the flame rod side is e and the current flowing through the flame (hereinafter referred to as ion current)
The force f flows in the direction of arrow E.

Reference numeral 16 indicates flame rectification Df, which indicates the rectification effect caused by the flow of ions in the flame. 17 is the flame resistance Rf of the resistance component when flowing through the flame, and the relationship between these is expressed as follows.

Flame resistance "Rf17 - DC applied voltage e f 15 / ion current If Here, if the balance of combustion is disrupted, it becomes difficult for the ion current If to flow, and the flame resistance R lower becomes large. Therefore, the chain consisting of the flame resistance Rf ( When the temperature exceeds 9 h/h, it is judged that the balance of combustion has been lost, and combustion is stopped.

In the above configuration, the gap between the ring-shaped frame rod 13A and the burner body 2 is such that even if the gap C on one side becomes large due to uneven installation, the gap on the other side will be the same distance. The sum of the gaps, that is, rc
+ DJ status will remain constant. Since the average value of the circumferential gap is always constant, the ionic current If flowing between the frame rod 13 and the burner body 20 is hardly affected by variations in the gap.

Also, the frame rod 1 is connected to the cylindrical burner body 2.
Since 3A is arranged in a ring shape, the frame rod 13A
corresponds one-to-one with respect to the circumferential direction of the burner body 20, and absorbs flame ions. Therefore, interference such as competing for ions does not occur, and the ion current If can be obtained most effectively, and its absolute chain becomes large, so that the normal chain has a margin with respect to the partition plate.

On the other hand, since the flame rod 13A is located around the outer periphery of the burner body 2, the flame formed on the surface of the porous tube 6 is maintained, that is, the flame is stabilized. Since the frame rod 13A is located over the entire outer periphery of the burner body 2, the flame stabilizing effect acts over the entire periphery of the porous cylinder 6. Therefore, combustion becomes stable, and at the same time, there is no need to take into consideration changes such as changing the shape of only the flame hole in that part, unlike conventional models where the flame rod is only in one part, and the shape of the flame hole in the burner head. becomes simple.

Effects of the Invention As described above, according to the present invention, it is possible to effectively obtain an ion current with a frame rod of a simple shape, and the influence of variations in the gap between the frame rod and the burner body due to variations in mounting can be avoided. can be reduced. Therefore, the combustion balance can be easily and reliably detected with one margin, and the liquid fuel combustion apparatus can be used safely for a long period of time.

[Brief explanation of the drawing]

FIG. 1 shows a liquid fuel fuel 11 in an embodiment of the present invention.
. 2 is a plan view of the same, FIG. 3 is an equivalent circuit diagram of the ion current, FIG. 4 is a sectional view of the main part showing a conventional example, and FIG. 5 is a plan view of the same. 1... Carburizer cylinder, 2... Burner body,
13A...Frame rod.

Claims (1)

[Claims] A vaporization tube that vaporizes liquid fuel and premixes the vaporized gas and combustion air, a cylindrical burner body that burns the premixed gas from the vaporization tube, and a premixed gas formed around the outer periphery of the burner body. a flame rod for detecting a combustion state of a burner body, the flame rod being formed in a ring shape so as to be located over the entire circumference of a burner body.