JPS5939646B2 - Combustion safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a combustion safety device that is effective not only when combustion is extinguished, but also particularly when the air inside a combustion chamber is contaminated and is in a so-called oxygen-deficient state.

Configuration of conventional example and its problems Figure 1 shows a thermocouple type combustion safety device that has been most commonly used in the past. In other words, 1 has a flame port 2 attached to the upper end and a nozzle 3 attached to the other end. Primary air port 4 on the peripheral wall
5 is a gas supply pipe, and 6 is a thermocouple, which is electrically connected to a solenoid valve (not shown) provided in the middle of the gas supply pipe 5.

In the above device, the gas enters from the gas supply pipe 5 and is ejected into the burner body 1 through the nozzle 3, and the ejector action accompanying the ejection causes primary air to be sucked through the primary air port 4. Further, secondary air is received at the burner port 2 and combusted to form a flame 7.

The above combustion method is generally called the Bunsen method.
Flame 7 is formed by 1 flame A and 2 flame S.

The thermocouple 6 is heated by this flame and generates a thermoelectromotive force that can keep the solenoid valve open. Therefore, when the combustion flame 7 is extinguished due to wind, etc., the solenoid valve is closed for safe operation. It is something.

In addition, the flame 7 is blown away when the oxygen concentration in the combustion air decreases, even in a so-called oxygen-deficient state, and therefore the thermoelectromotive force of the thermocouple 6 decreases, closing the solenoid valve.
A kind of oxygen deficiency safety operation can be expected.

However, expecting a completely safe operation due to lack of oxygen from the above-mentioned device, which was originally intended as a countermeasure against blowouts caused by wind, etc., had the following major problems.

The first point is that if flame 7 is blown away,
This occurs depending on the mode of air flow, and the above-mentioned blown-off oxygen concentration value in the air, the so-called "blown-off oxygen concentration value," varies greatly, making it unreliable as an oxygen deficiency safety measure. can give.

The second problem is that even if the flame 7 is once blown away, it can be easily re-ignited by the combustion heat of the main burner, making it susceptible to the influence of surrounding conditions.

A third point is that the blown-off oxygen concentration value varies depending on the type of gas.

In other words, when comparing methane-based gas (natural gas) and hydrogen-based gas (city gas), the former gas is much more likely to cause blow-off than the latter gas, and the latter hydrogen-based gas in particular causes primary flame damage. Even if the flame tries to blow off, the secondary flame remains at the flame mouth, resulting in stable combustion with a low oxygen concentration.

For this reason, the blown-off oxygen concentration values for both gases are large (
It's going to be different.

OBJECT OF THE INVENTION The present invention solves such conventional problems, and aims to blow out flames without being affected by external influences, and in particular, to enable detection of oxygen deficiency in hydrogen-based gases. do.

Structure of the Invention In order to achieve this object, the present invention configures a burner so that a primary flame (inner flame) and a secondary flame (outer flame) are formed at a certain distance, and the heating area of the primary flame is A primary flame detection element such as a thermocouple and a flame rod nut is installed in the primary flame detection element, and this primary flame detection element is connected to a fuel control valve.When the oxygen concentration in the air decreases, the primary flame is blown out and the primary flame is blown out. It has the effect of changing the output of the flame detection element and closing the fuel control valve.

Description of examples An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, reference numeral 11 denotes a burner body for ignition, etc., which is provided in close proximity to the main burner, and is composed of an inner cylinder 12 and an outer cylinder 13.

The outer cylinder 13 has a secondary flame port 14 at the upper end, and a flange 15 extending inward from the opening edge at the lower end.

Reference numeral 16 denotes an additional envelope that is diagonally connected to the outer cylinder 13.

On the other hand, the inner cylinder 12 has a primary burner port 17 at its upper end that faces into the outer cylinder 13 and is located a certain distance below the secondary burner port 14, and further has a primary air port 18 formed in the lower peripheral wall. be.

The inner cylinder 12 has a flange 19 provided in the middle thereof.
After contacting the upper surface of the flange portion 15 of the outer cylinder 13, the inner cylinder 1
By pressing a nut 21 screwed onto the threaded portion 20 of No. 2 onto the lower surface of the flange portion 15 via a packing 22, the nut 21 can be removably attached to the outer cylinder 13.

23 is a gas nozzle attached to the lower opening of inner 12, 24
1 placed near the primary flame opening 17 via the envelope 16
Next flame detection element (hereinafter referred to as a thermocouple).

) and is electrically connected to the solenoid valve of the gas supply path.

In the above configuration, the gas ejected from the gas nozzle 23 and the primary air sucked from the primary air port 18 are
2 and burns at the primary flame port 17 to form 1 flame A.

Furthermore, this combustion gas is ejected from the secondary flame port 14 of the outer cylinder 13, obtains air from the surroundings, that is, secondary air, and burns to form a second flame B.

The thermocouple 24 is located in contact with or in close proximity to the hottest flame surface of flame A, and therefore
When the flame A is formed, its heating generates a thermoelectromotive force capable of opening and holding the solenoid valve.

By the way, one flame A, which is originally independent, is composed only of premixed coal, and is very sensitive to oxygen concentration.

Further, since the single flame A is covered by the outer cylinder 13, it is not affected by surrounding influences such as the influence of the main burner or the influence of secondary air flow.

Therefore, when the oxygen concentration in the primary air becomes below a certain level,
1 Since the flame A is blown away, the thermoelectromotive force of the thermocouple 24 disappears, closing the solenoid valve and cutting off the subsequent gas supply.

2.Flame B is a diffusion flame, and 1.flame A is not sensitive to oxygen concentration (2) Flame B remains even after 1.flame A is blown away.

Next, if there is a change in gas quality, it can be easily dealt with by replacing the gas nozzle 23 and the inner cylinder 12.

At this time, the diameter of the inner cylinder 12, to be more precise, the primary flame port 17
By appropriately setting the aperture of the gas, the same "blown-off oxygen concentration value" can be obtained for the combustion speed of various gases, and variations depending on the gas type can be prevented.

In addition, since hydrogen-based gas has a much higher combustion speed than other gases, it is necessary to take a structural measure to make the one-deletion port 17 more likely to be blown away.

For example, deletion 1-17 may be made into a knife shape as shown in FIG. 3, or an orifice shape as shown in FIG. 4.

Next, the secondary flame B formed at the 2-deletion port 14 is the primary flame A.
It is preferable to leave it for 30 to 60 seconds after it is blown off.

That is, by maintaining the above-mentioned two deletions B, even if gas is ejected from the main burner until the primary flame A is blown away and the thermocouple 24 closes the solenoid valve, it will be ignited by the secondary flame B. This can prevent poisoning and explosions caused by raw gas leakage.

In FIG. 5, the 2-deletion hole 14 is made step-shaped for this purpose, and the stepped portion improves the ability to retain the 2-deletion, and in FIG. A flame impingement body 26 is disposed opposite to the two-hole opening 14 via a plurality of elastic legs 25 to suppress blow-off of the secondary flame B.

Furthermore, FIGS. 7 and 8 show a case in which a cooling means is provided in the outer cylinder 13 in order to prevent the inside of the outer cylinder 13 from being overheated due to the influence of the combustion heat of the main burner and deteriorating the blow-off characteristics of the primary flame A. In Fig. 7, a wind cylinder 27 is provided on the outside of the outer cylinder 13 so that convection air flows through the gap t between the two, and Fig. 8 shows the part of the outer cylinder that is not exposed to the combustion heat of the main burner. 13
radiating fins 28 are provided from the outside.

It is also conceivable that the outer cylinder 13 be made of a heat insulating material such as porcelain as shown in FIG.

In the above embodiments, a thermocouple was used for primary flame detection, but other devices may also be used, such as a temperature-resistance element such as a thermistor, a thermally responsive element such as a bimetal element, a liquid-expandable heat-sensitive element, or a CDS element. A similar effect can be expected by employing an oxygen sensor such as an ion current sensing element such as a photosensitive element frame or rod that responds to light generated from a flame, or tin oxide.

Furthermore, in the above embodiment, the inner cylinder 12 is made into a cylindrical shape, and the primary air port 17 is opened in the lower part at a right angle to the inner cylinder 12, and the gas nozzle is exposed. As long as the structure is covered with the outer cylinder 13 in order to achieve this, it is possible to use not only the above embodiment but also a burner structure having a general mixing pipe for premixing a predetermined primary air. Similar effects can be obtained even when configured as a main burner.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention includes an inner cylinder having a flame port on one side and a primary air port facing from a gas nozzle on the other side, and a secondary air port at a certain distance from the first flame port. a burner body consisting of an outer cylinder having a flame port formed therein; a primary flame detection element that detects one flame formed in the one flame port; and a valve that controls fuel supplied to the gas nozzle by the primary flame detection element. By configuring the following, the following effects can be obtained.

(1) In Bunsen flame, there is a supply of secondary air, and in hydrogen-based gas, combustion is stable even when the oxygen concentration decreases, but since the flame changes depending on the oxygen concentration and is formed with premixed coal, hydrogen-based gas Oxygen deficiency conditions can be detected early even in gases with high combustion speeds, such as gases with high combustion rates.

(2) The first flame is covered by an outer cylinder and is not affected by the flow of secondary air.

Also, for the same reason, when the present invention is used as a pilot burner, it is not affected by the main burner.

(3) Furthermore, by making the inner cylinder freely attachable and detachable, combustion settings can be freely set for more gas types.

(4) Furthermore, by forming one flame port into an acute-angled or constricted shape, one flame can be blown out more quickly when the oxygen concentration decreases.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of a conventional combustion safety device, Fig. 2 is a sectional view of a combustion safety device showing an embodiment of the present invention, and Figs. 3 and 4 show other embodiments of the inner cylinder. Partially cutaway front view shown, No. 5
Figure 6 is a partially cutaway front view showing an embodiment of the outer cylinder, and Figure 7 is a partially cutaway front view showing an embodiment of the outer cylinder.
The figure is a sectional view showing still another embodiment of the outer cylinder, and FIGS. 8 and 9 are front views showing still other embodiments of the outer cylinder. 11...Burner body, 12...Inner cylinder,
13...Outer cylinder, 14...Secondary flame port, 1
7...1 flame port, 18...primary air port, 23...gas nozzle, 24...primary flame detection element (thermocouple).

Claims (1)

[Scope of Claims] 1. An inner cylinder having one flame port facing from the gas nozzle on one side and a primary air port on the other side, and an outer cylinder having two flame ports formed at a certain distance from the first flame port. A combustion safety device comprising: a burner body consisting of a cylinder; a primary flame detection element for detecting one flame formed in the one flame port; and a valve for controlling fuel supplied to a gas nozzle by the primary flame detection element. 2. The combustion safety device according to claim 1, wherein the inner cylinder is configured to be detachable. 31. The combustion safety device according to claim 1, wherein the edge of the flame port has an acute angle. 41. The combustion safety device according to claim 1, wherein the edge of the flame port is formed into a constricted shape.