JPS6113529B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a burner for small appliances such as home hot air heaters and hot water boilers. (1) The inside of the vaporization chamber is coated with a paint that has a catalytic action and is made by adding alkali to an inorganic heat-resistant paint. By doing so, it is possible to prevent tar adhesion, CO, soot generation, etc., and achieve complete combustion. (2) Simple structure, quick ignition start-up, and stable blue combustion. (3) It is safe and easy to ignite and extinguish, and there is no risk of explosion. (4) The purpose is to make it small and compact. Conventionally, there are many types of liquid fuel burners for small home appliances, but they can be broadly categorized into:
Pot-type burners, vaporization-type burners that heat, gasify, and burn fuel using an electric heater, wick-type burners that soak fuel into a wick made of braided glass fiber, suck air through natural draft, and burn it, etc. There is. Pot type burner A metal pot serves as the evaporator. Fuel is supplied into the pot, and the flame after ignition heats the bottom of the pot and evaporates the fuel to continue combustion. Since the fuel gathers in the center of the pot, that is, there is no suction of fuel to the entire surface of the pot, it takes about 10 minutes from ignition to steady combustion.Although the pot has a relatively simple structure and low cost, As a result, the fuel that accumulates in the center is carbonized at high temperatures.
Tar is easily generated and soot due to incomplete combustion.
CO, easily generates odor. Furthermore, even if the fuel supply is stopped and the fire is extinguished, the fuel remaining at the bottom of the pot will gradually evaporate, but during this time, as mentioned above, tar formation will be extremely accelerated. Next, the vaporization burner, which has a special vaporization device incorporating a 400W to 1KW electric heater, premixes the vaporized fuel gas and air, producing blue-fire combustion with low combustion noise similar to city gas or propane gas. However, during ignition operation, from the time the electric heater is energized until the vaporization device reaches a temperature at which it can vaporize the fuel.
It takes 10 to 20 minutes and it is impossible to start combustion immediately. Furthermore, it is necessary to keep the temperature of the vaporized gas constant during combustion, and the vaporization device requires a complicated and expensive temperature control device. If the temperature of the vaporized gas is too low due to tar adhering to the vaporization section, it may re-liquefy before reaching the combustion section, resulting in insufficient combustion, or the air-fuel ratio may become unbalanced, resulting in blowout. In addition, tar formation is promoted while reaching the vaporization section and combustion section.
On the other hand, if the temperature of the vaporized gas is too high, the balance between the ejection speed of the premixed gas and the combustion speed in the combustion section having slits etc. is lost, and flashback is likely to occur. A wick burner is a typical combustion device that uses an evaporator, and is a wick made of a braided glass or cotton wick, which is impregnated with material and burned in a natural draft. Recently, it has been widely used in stoves, etc., but as the combustion is kept balanced by natural draft, combustion is extremely unstable, and tar and odor are the biggest problems, especially tar on the lamp wick. Adhesion is becoming difficult. In this case, the combustion gas is forcibly discharged outside, but it is very difficult to stabilize the combustion when using a blower that forcibly supplies combustion air. Therefore, the present invention aims to provide a novel liquid fuel combustion apparatus that eliminates the above-mentioned conventional drawbacks, and one embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a side sectional view of an embodiment of the present invention.
In the figure, reference numeral 1 denotes an outer cylinder, which is provided with a fuel supply pipe 2 and a fuel return pipe 3. 4 is an ignition heater and has a coil 5 that becomes red hot when energized. Further, the outer cylinder 1 is provided with a partition plate 6 and a guide 7.
Reference numeral 8 denotes a surface coated with heat-resistant paint, which serves as a vaporization chamber on the inner side of the outer cylinder 1. Reference numeral 9 denotes an inner cylinder having a hole 10 and a shaft 11 fixed thereto. 12
is a blower cylinder located outside the inner cylinder 9 and fixed to the outer cylinder 1. Reference numeral 13 denotes an air intake port, and 14 denotes a middle cylinder through which air is spun and ejected through a plurality of small holes 15 cut and raised. Further, one end of the middle cylinder 14 is fixed to the inner cylinder 9. Reference numeral 16 denotes a swirling flame formed, and reference numeral 17 denotes a mixing chamber formed between the heat-resistant paint coating surface 8 and the middle cylinder 14, in which vaporized gas and air from the middle cylinder 14 are mixed. Reference numeral 18 denotes a combustion chamber formed between the heat exchanger 20 and the middle cylinder 14, in which the premixed gas obtained in the mixing chamber 17 is combusted by the air swirling and jetting out from the middle cylinder 14. 19 is a sealing material between the outer cylinder 1 and the heat exchanger 20, 2
1 is a hot water outlet, 22 is a water supply port, and 23 is a combustion gas discharge port. In FIG. 2, 24 is a blower, 25 is a pump that supplies a fixed amount of fuel, and 26 is an oil tank. FIG. 3 shows a cross section of the middle cylinder 14. Next, the operation will be explained. First, the ignition heater 4, the blower 24, and the pump 5 are energized. The coil 5 of the ignition heater 4 becomes red hot, and fuel is supplied from the tank 26 at a set flow rate through the fuel supply pipe 2 to the vaporization chamber 8 on the inner side of the outer cylinder 1 coated with heat-resistant paint, where it vaporizes on the coating surface. , the flame ignited by the red-hot coil 5 enters the middle cylinder 14 in the mixing chamber 17.
Yellow flame combustion is carried out by the air supplied by the fuel, but the temperature rises, vaporization of the fuel is promoted, and the combustion flame moves from the mixing chamber 17 to the combustion chamber 18 within about 30 seconds. That is, the combustion chamber automatically changes from yellow combustion in the mixing chamber 17 to blue combustion in the combustion chamber 18. When the amount of vaporized gas generated increases, a mixed gas state of vaporized gas and air from the middle cylinder 14 occurs in the mixing chamber 17, and this premixed gas is not combusted and reaches the combustion chamber 18, where it is swirled and ejected from the middle cylinder 14. The addition of air causes green flame combustion. During steady blue flame combustion, the vaporization surface is heated by radiant heat and heat conduction from the flame, promoting vaporization of the fuel and continuing combustion. Also, when extinguishing a fire, stop the pump 25 and cut off the fuel supply, and the fire will be extinguished within 60 seconds. If you want to extinguish the fire even more instantaneously,
When the pump 25 is stopped, the inner cylinder 9 is moved by the shaft 11 and a part of the inner cylinder 9 is brought into contact with the partition plate 6 of the outer cylinder 1, thereby generating gas from the vaporizing surface (vaporizing part) coated with heat-resistant paint. Cut off vaporized gas. The overall configuration of the present invention is shown in FIG. 2, where an oil tank 26 is provided at a lower position than the outer cylinder 1, and a pump 25 supplies fuel to the vaporization section. In the event that the coil portion 5 of the ignition heater 4 is broken and cannot be ignited, the fuel is configured to accumulate in the lower part of the outer cylinder 1 and be led to the oil tank 26 through the return pipe 3. The biggest problem with liquid fuel combustion equipment is tar that adheres to the vaporization section and fuel supply hole.
This is the generation of carbon (soot), CO, and odor. In particular, the influence of contaminated oil or foreign oil is extremely large. Although various attempts have been made to address these problems, at present no definitive method has been found. The present invention is made of an alkali metal silicate, an acidic metal phosphate, and a metal oxide pigment with excellent heat resistance, and has an extremely excellent catalytic effect <tar suppression effect> on an inorganic heat-resistant paint containing an alkali.
By coating the vaporization part with this type of heat-resistant paint (catalyst), we have created a combustion device that prevents tar adhesion and carbon precipitation, and can perform ideal oil combustion without generating CO or odor. This is what we do. When surface-treating the entire surface of the vaporization section (evaporation section) of a liquid fuel combustion device with a heat-resistant paint with excellent catalytic effect (inorganic heat-resistant paint coating), the requirements are heat resistance, oil resistance, thermal shock resistance, and adhesion. Such as gender. Regarding heat resistance, alkali metal silicate <
Our inorganic heat-resistant paint, which consists of sodium silicate, acidic metal phosphate, and metal oxide pigments, has already been applied to our gas stoves, stove burner caps, and trivets, and has a considerable track record. Burner caps are heated to around 500 degrees Celsius, and the tips of the trivets' claws, in particular, are exposed directly to the flame, reaching a temperature close to red-hot, and the color may fade slightly even after long-term use. There is no problem at all with respect to heat resistance and long-term thermal stability. Furthermore, even if alkali is added to this heat-resistant paint,
The paint itself has basic components and can be mixed in any proportion, and it has been confirmed that there is no change in heat resistance after addition. Potassium carbonate <
The results of thermogravimetric analysis of paints with K ₂ CO ₃ >5wt% added using a thermobalance show that from the start of heating
Up to about 200℃, a slight weight loss is observed due to the scattering of contained moisture, but when heated further to about 600℃, no weight change is observed at all, indicating that even with the addition of alkali, the thermal stability of the heat-resistant paint is affected. It has no effect at all. Regarding oil resistance, we confirmed the change over time in the hardness (crushing strength: using a Kiya-type manual hardness tester) of paints that were cured by immersing them in kerosene or light oil. The paint to which 5wt% of potassium carbonate <K ₂ CO ₃ > was added as an alkali was prepared into a dice shape of 5 mm x 5 mm x 5 mm and was used as a sample. In the continuous immersion test for 6 months, there was very little change in hardness, and the initial 15 kg (number of samples =
10) is 13.8Kg (same) when immersed in kerosene.
In light oil, it maintains a strength of 13.5 kg (same).
It was confirmed that there was no concern about the paint softening or collapsing even after long-term immersion. It is soaked in fuel oil during the off-season,
This means that there is no need to worry about it even if it is left alone. Regarding thermal shock resistance, during use, the material was subjected to repeated ignition and extinguishing, and changes in hardness due to repeated heating and cooling were confirmed. The sample used was the same as the one used to evaluate oil resistance, and was heated at 300℃ for 8 hours - 10℃16
A total of 1000 cycles were carried out, with time cooling as one cycle, and the weight was maintained at 12.9 kg, which was extremely good. Furthermore, regarding thermal shock resistance when formed on a paint film, K ₂ CO ₃ 5wt as an alkali is added to the heat-resistant paint.
% was added and applied on a metal plate, and a heat shock test was conducted. The test piece is a 20mm x 50mm SPCC coated with paint 30 mm thick.
A sample coated with μ was prepared and evaluated. each sample at 100℃, 200℃, 300℃, 350℃,
One cycle consisted of heating to 400°C and then rapidly cooling in water, and 10 cycles were repeated at each temperature to check for cracks and peeling of the coating. As a result, no change in the coating film was observed at any temperature, and the thermal shock resistance and adhesion of the coating film were extremely good regardless of whether or not alkali was added. As mentioned above, even when alkali is added to this heat-resistant paint, its heat resistance, long-term thermal stability, oil resistance, thermal shock resistance, and adhesion remain unchanged and maintain sufficient performance as a heat-resistant paint. ing. Figures 5 and 6 show the results of oil resistance and impact resistance. Next, we will discuss the tar suppression effect (performance) of this heat-resistant paint with alkali added. FIG. 4 is a cross-sectional view of the reactor. In the figure, 27 is the device body, 28 is the oil supply pipe, and 29
30 is a primary air supply pipe, 30 is a secondary air supply pipe, and 31 is a flame hole. The main body 27 includes a vaporizing section 32
It consists of a premixing section 33 and a combustion section 34 having flame holes 31. The primary air supply pipe 29 has a plurality of ejection holes 35
have. Reference numeral 36 denotes a heating heater, which heats and maintains the device 27 at a constant temperature, sends a constant amount of fuel to the fuel supply pipe 28, 8 μm, and starts combustion through the primary air supply pipe 29 and the secondary air supply pipe 30. The fuel is vaporized and mixed as it rises, igniting it at the flame hole part 31.
It is made to burn. Also, the flame hole part 31
It also serves as a sampling part to confirm how the vaporized gas has changed and to collect gas. To check the tar suppression effect, check the bottom surface of the vaporizing section 32.
It was spread over a surface and burned in a reaction device 27 for a certain period of time, and the degree of tar and carbon adhering to each part was compared. The implementation method was to heat and maintain the device at a temperature of 300℃, and in order to check for tar in a short time, light oil was burned for 2 hours, and then the tar attached to the vaporization part and around the combustion supply hole was observed, and the acetone After cleaning with acetone and extracting the tar, we compared the effectiveness of acetone based on the degree of coloring (degree of solubility of tar). In addition, after the paint is cured, it is crushed to a predetermined particle size.
It is classified and a certain amount of it is used. The degree of coloring was determined by measuring absorbance at a wavelength of 420 mμ using a spectrophotometer. Alkali metal silicate (sodium silicate),
This heat-resistant paint, which contains acidic metal phosphate and metal oxide pigments with excellent heat resistance, already has a considerable track record in practical use, and has excellent heat resistance,
It must have excellent impact resistance and adhesion, and these properties must not be impaired by additives. Particularly when applied as a coating, paintability as a paint is also an important factor, and it is most important to take into account the above-mentioned characteristics as well as performance. Table 1 shows each composition that was evaluated.

【table】

【table】

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[Table] Among the inorganic heat-resistant paints with alkali added, the one with K ₂ CO ₃ added was particularly good.
Table 2 shows the absorbance measurement results at 420 pμ of acetone extracts for representative samples with good results. <Both were extracted with 100cc of acetone. >When burning liquid fuel, the decomposition of hydrocarbons results in by-products of tar and carbon, which are caused by unsaturated hydrocarbons polymerizing to become polycyclic aromatics and turning into tar. Alternatively, this is because the C--C bond is directly cut to generate carbon, which is then deposited and precipitated. In these reactions, it is said from experience that it is possible to burn carbon etc. even at fairly low temperatures in the presence of alkali, etc., and there are many introductions and proposals in literature and special reports. The effect of potassium carbonate (K ₂ CO ₃ ) is not clear, but K (potassium) has a much higher reactivity with O ₂ , H ₂ , C, CO, or water vapor than other substances. This is thought to be due to a synergistic effect with the basic heat-resistant paint. When other alkalis shown in Table 1 are added to paints, they have poor solubility and may cause sedimentation, or a sudden increase in viscosity or hardening, which may impede paintability. So it's not desirable. Figure 7 shows the results regarding the influence of the amount of potassium carbonate <K ₂ CO ₃ > added. In particular, the addition of potassium carbonate can be expected to have an extremely large effect on tar suppression, but from the viewpoint of performance, paintability, and physical properties, the amount added should be 1 to 20 wt% (preferably 5 to 15 wt%) of the total amount. ) is appropriate; anything above this is not preferred as it tends to affect paintability and deteriorate performance. As mentioned above, this heat-resistant paint with alkali added has good heat resistance, oil resistance, thermal shock resistance, adhesion,
Furthermore, the tar suppression effect was extremely excellent, and the durability evaluation using an actual combustion device (continuous combustion test) also showed good results. Apply this heat-resistant paint containing 5 wt% of potassium carbonate <K ₂ CO ₃ > to the inside of the combustion equipment vaporization chamber (there are no particular restrictions on the coating method. (pretreatment is necessary), 8 times a day
We conducted a continuous combustion test for 3 months, but no tar adhesion or carbon precipitation was observed.
The initial goal of controlling tar was fully achieved. The problem of tar adhesion, which was the biggest problem with conventional liquid fuel combustion equipment, has been completely solved by a never-before-seen decomposition solution created by improved heat-resistant paint, which is of great industrial value. It has a high value.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a liquid fuel combustion device showing an embodiment of the present invention, Fig. 2 is a side view of the main fuel supply section, Fig. 3 is a sectional view of the middle cylinder, and Fig. 4. is a cross-sectional view of the reactor, Figure 5 is a diagram showing changes in hardness due to immersion in kerosene and light oil, Figure 6 is a diagram showing changes in hardness due to heat shock test, and Figure 7 is a diagram showing the amount of K ₂ CO ₃ added and tar suppression effect. FIG. 1... Outer cylinder, 2... Oil supply pipe (paint supply means), 4... Ignition heater, 5... Coil, 6...
Partition plate, 7... Guide, 8... Vaporization chamber, 9... Inner tube, 12... Blower tube, 14... Middle tube (air supply means).

Claims (1)

[Scope of Claims] 1. A mixing chamber for mixing vaporized gas of liquid fuel and combustion air, a fuel supply means for supplying liquid fuel to the mixing chamber, and an air supply means for supplying combustion air to the mixing chamber. The inner surface of the vaporization chamber in the mixing chamber is coated with an inorganic heat-resistant paint consisting of an alkali metal silicate (sodium silicate), an acidic metal phosphate, a metal oxide pigment with excellent heat resistance, and further containing an alkali. Coated liquid fuel combustion device. 2. Claim 1, in which the inside of the vaporizer chamber is coated with an inorganic heat-resistant paint to which one or more selected from the group of alkali metals or alkaline earth metal oxides, hydroxides, or carbonates is added as an alkali. The liquid fuel combustion device described. 3. The liquid fuel combustion device according to claim 2, wherein the inside of the vaporization chamber is coated with an inorganic heat-resistant paint to which potassium carbonate <K ₂ CO ₃ > is added. 4. Claim 3, in which the inside of the vaporization chamber is coated with an inorganic heat-resistant paint containing potassium carbonate (K ₂ CO ₃ ) in an amount of 1 to 20% of the total amount by weight.
The liquid fuel combustion device described in .