JPH0252174B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal processing apparatus that uses liquefied gas such as butane gas as a fuel gas, and particularly relates to an improvement in an automatic ignition mechanism.

[Prior art]

Conventionally, thermal processing equipment using liquefied gas is
For example, Special Publication No. 55-29789 or Special Publication No. 55
The automatic ignition mechanism shown in Japanese Patent No. 6033 has been proposed, and generally known automatic ignition mechanisms include those using an electric ignition heater or those using a piezoelectric ignition plug.

However, those using electric ignition heaters have a problem in that the heater is cooled by the fast-flowing mixed gas, making ignition difficult. In order to prevent this, a high-output battery may be connected to the heater, but if this type of battery is incorporated into a thermal processing device, there is a problem that the device becomes large.

On the other hand, piezoelectric ignition plugs have the advantage of being able to reliably ignite even when the flow rate of the mixed gas is high, and because the ignition mechanism can be made compact, it can be easily incorporated into small thermal processing equipment. have.

However, in the conventional thermal processing equipment, the mixed gas discharged from the nozzle is ignited using a piezoelectric ignition plug to cause primary combustion with flames at the nozzle, and the combustion exhaust is subjected to secondary combustion using a combustion catalyst. Because of this method, the flame cannot be extinguished, resulting in poor thermal efficiency, and if the flow rate of the mixed gas is large, the flame may escape from the surrounding surface of the combustion catalyst.
There are problems such as interfering with work.

Therefore, the present applicant previously proposed in Japanese Patent Application No. 59-30064 a thermal processing device in which the temperature of the combustion catalyst is raised to the reaction temperature by flaming combustion, and then the shutter is closed to extinguish the flame. This has made it possible to flamelessly burn the entire amount of mixed gas using the combustion catalyst.

However, when a piezoelectric ignition plug is incorporated into a thermal processing apparatus having a shutter mechanism, there is a problem in that the apparatus configuration becomes extremely complicated and the cost increases.

[Purpose of the invention]

The present invention was developed in view of the current situation, and it is possible to incorporate an automatic ignition mechanism with a simple device configuration, and furthermore, after the combustion catalyst reaches the reaction temperature, the flame is automatically extinguished and the entire amount of mixed gas is combusted. The purpose of the present invention is to provide a thermal processing device using liquefied gas that can be burned flamelessly with a catalyst.

[Summary of the invention]

The present invention includes a gas ejection section that ejects fuel gas;
A cylindrical mixed gas that is installed on the exit side of the gas jetting part and uses the ejector action of the gas injected from the gas jetting part to draw in excess air from the outside compared to normal flaming combustion to generate excess air mixed gas. A generating section, a cylindrical ignition tube with an open end having a larger cross-sectional area than the mixed gas generation section, and a combustion catalyst disposed at the tip of the ignition tube for flameless combustion of the mixed gas are incorporated inside. A soldering iron tip and a piezoelectric ignition plug disposed in the ignition tube are provided, and the piezoelectric ignition plug ignites excess air mixed gas discharged from the mixed gas generation section to eliminate unstable air in the ignition tube. It is possible to perform flaming combustion for a short time, use the combustion heat to heat at least the base end of the combustion catalyst to the reaction temperature, and then automatically extinguish the flame after ignition by an automatic ignition mechanism. The feature is that the device configuration can be simplified.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, 1 is a gas tank for liquefied gas such as butane gas, which is attached to the base of a rod-shaped handle 2, and an injection valve 3 is attached to the base end of the tank.
is provided. Furthermore, an outlet valve 5 having a gas suction body 4 is assembled at the tip of the gas tank 1, as shown in FIG. As shown in FIGS. 1 and 2, this outlet valve 5 includes a flow rate control section 6 that rotates around the axis to control the discharge flow rate of gas, and a flow rate control section 6 that rotates around the axis to control the discharge flow rate of the gas. A valve opening/closing member 8 is provided for moving the nozzle 5a back and forth in the axial direction via a stopper 7 to open and close the outlet valve 5.
The valve opening/closing member 8 is connected to the handle 2 as shown in FIG.
It is pressed and biased to the right in the figure by a spring 9 incorporated therein.

As shown in FIGS. 1 and 2, the base end of a cylindrical outer case 10 made of stainless steel or the like is removably fixed to the tip of the handle 2 via a nut 11. A contact type soldering iron tip 12 is attached to the tip of the case 10 in a state where it is prevented from coming off toward the tip side.

On the other hand, the base end of a gas introduction metal pipe 14 is connected to the tip of the nozzle 5a of the outlet valve 5 via a flexible tube 13, as shown in FIG.
This gas introduction metal pipe 14 is attached to the outer case 10 with its base end fixed to the tip of the handle 2.
protrudes inward. At the tip of this gas introduction metal pipe 14, there is a mixed gas generation metal pipe 15.
The base end of the mixed gas generating pipe 15 is connected to the base end of a mixed gas deriving metal pipe 16.

In the mixed gas generating metal pipe 15, a first
As shown in the figure, an orifice 17 with a diameter of about 60 to 80 μm is provided for a gas pressure of, for example, 1.5 to 2 Kg/cm ² , and a sintered metal, for example, A filter 18 is incorporated therein, and an air suction hole 20 is provided on the outlet side of the orifice 17 for sucking external air into the mixed gas generating metal pipe 15 through an air port 19 provided in the outer case 10. There is. The air sucked through the air suction hole 20 and the fuel gas discharged from the orifice 17 are mixed in the mixed gas generation metal pipe 15, and a mixed gas containing more air than in normal flaming combustion is generated. It is becoming more and more common.

In other words, when the mixed gas burns with a stable flame at the tip of the mixed gas lead-out metal pipe 16, the volume ratio of fuel gas to air is about 1:30.
The volume ratio of fuel gas and air in the mixed gas discharged from the tip of the mixed gas deriving metal pipe 16 is:
Approximately 1:33~1:40, in other words, the air is 1~1:40.
The amount of mixed gas is about 30% excessive. This mixing ratio is determined experimentally according to the dimensions and shape of the thermal processing apparatus, and can be easily obtained by appropriately adjusting the diameter of the orifice 17 and the opening area of the air suction hole 20 with respect to the gas pressure.

At the tip of the mixed gas lead-out metal pipe 16,
As shown in FIG. 1, an ignition tube 21 in the shape of a cylinder with a bottom that is open only on the tip side is fixed, and the opening edge of the tip is in close contact with the base end of the soldering tip 12. is being fixed.

As shown in FIG. 1, this ignition tube 21 is made of, for example, mica ceramics, alumina ceramics,
It is made of an electrically insulating material with low thermal conductivity and a translucent material, such as zirconia ceramics, quartz glass, or crystal glass, and its cross-sectional area in the direction perpendicular to its axis is equal to that of the mixed gas deriving metal. The cross-sectional area of the pipe 16 is set larger than the similar cross-sectional area of the pipe 16, and the flow velocity of the excess air mixed gas discharged from the mixed gas deriving metal pipe 16 is reduced within the ignition tube 21.

As shown in FIG. 2, a piezoelectric spark plug 22 is installed in the ignition tube 21 to generate an electric discharge between it and the tip of the mixed gas lead-out metal pipe 16. The mixed gas output metal pipe 16 is connected to the (+) side of the piezoelectric ignition element 25 via a high voltage cable 24 passing through the mixed gas generating metal pipe 15,
It is connected to the (-) side of the piezoelectric ignition element 25 via the gas introduction metal pipe 14 and the ground wire 26 . Then, as shown in FIGS. 1 and 2, by pressing the ignition button 27 provided on the handle 2, electric discharge occurs between the piezoelectric spark plug 22 and the mixed gas lead-out metal pipe 16, and the mixture is mixed. The excess air mixture gas discharged from the gas outlet pipe 16 is ignited, causing an unstable short period of time (1
flammable combustion takes place for about 5 seconds). Due to this short-time flaming combustion, at least the base end portion of the combustion catalyst 28 incorporated in the tip 12 is heated to the reaction temperature (180 to 190°C),
After the flame is extinguished, the entire amount of excess air-mixed gas is flamelessly combusted at the combustion catalyst 28, and the combustion exhaust is distributed to the circumferential surface of the tip 12 as shown in FIG. It is designed to be discharged from an exhaust port 12a provided in the. Further, the combustion state in the combustion catalyst 28 is determined by the ignition pipe 21 at the tip of the outer case 10.
This can be confirmed through a viewing window 29 provided at a portion corresponding to the circumferential surface of the camera. For example, when the ignition tube 21 is an opaque milky white color, the ignition tube 21 receives reflected light due to combustion in the combustion catalyst 28 and becomes red, and the temperature level (that is, the combustion state) can be determined from the color change. It's summery.

As shown in FIGS. 1 and 3, the combustion catalyst 28 is made by supporting a noble metal catalyst such as platinum or palladium on the surface of a cylindrical carrier made of, for example, cordierite ceramics, which has square-shaped partitions inside. The support is designed to be thin enough to not pose a problem in practical use or production, and to be easily heated to the reaction temperature.

Next, the effect will be explained.

In use, first operate the flow rate control member 6 to set the opening degree of the outlet valve 5 to an appropriate value, and
The outlet valve 5 is opened by operating the valve opening/closing member 8. Then, the fuel gas in the gas tank 1 is guided into the mixed gas generation metal pipe 15 via the nozzle 5a of the outlet valve 5, the flexible tube 13, and the gas introduction metal pipe 14, and the filter 18 removes foreign substances. After that, it is injected from the orifice 17.

When fuel gas is injected from orifice 17,
Due to its ejector action, external air is sucked into the mixed gas generating metal pipe 15 through the air port 19 and the air suction hole 20, and an excess air mixed gas is generated within the mixed gas generating metal pipe 15. This excess air mixed gas is removed from the mixed gas outlet metal pipe 16.
It is discharged into the ignition tube 21 through.

In this state, when the ignition button 27 is operated to ignite, as shown in FIG. The gas mixture is ignited. Then, as shown in FIG. 4b, the excess air mixture gas in the ignition tube 21 causes unstable combustion accompanied by the flame 30 for a short period of time (1~ (about 5 seconds)
It is done. This flaming combustion causes the combustion catalyst 28
After the base end of the ignition tube 21 is heated to the reaction temperature and the flame 30 is extinguished, the entire amount of the excess air mixture in the ignition tube 21 is guided to the combustion catalyst 28 position and becomes flameless, as shown in FIG. 4c. Subjected to combustion.

By the way, when the amount of air in the mixed gas discharged from the mixed gas lead-out metal pipe 16 into the ignition tube 21 is set to the optimum value for flaming combustion, the tip of the mixed gas lead-out metal pipe 16 is fixed. A flame forms as a point, and in this case, it becomes stable flaming combustion, so the flame cannot be extinguished automatically.
The temperature of the iron tip 12 becomes low.

On the other hand, an excess air mixture results in unstable combustion with a flame 30 without a fixed point.
In this case, the flame 30 has a property that if there is a fixed point, it tries to burn starting from that fixed point, so when the base end of the combustion catalyst 28 becomes high temperature, it tries to use this part as the fixed point. . However, even if flaming combustion is attempted using the high-temperature part at the base end of the combustion catalyst 28 as a fixed point, no flame will be generated because the interior of the combustion catalyst 28 has a structure with many small axial through holes. The exhaust port 12a of the tip 12 cannot also be a fixed point because the temperature is low and the exhaust flow rate is high. Therefore, when the base end of the combustion catalyst 28 reaches a high temperature and starts an oxidation reaction, the flame 30 is completely extinguished, and from then on, excess air-mixed gas is directly supplied to the combustion catalyst 28. As a result, the entire amount of fuel gas is combusted within the iron tip 12, and complete flameless combustion is achieved using the combustion catalyst 28. The light from this combustion is reflected on the ignition tube 21, and for example, if the ignition tube 21 is milky white,
The ignition tube 21 will be dyed red. By checking this color through the viewing window 29, the state of flameless combustion by the combustion catalyst 28 can be determined.

Note that, since the excess air mixed gas is permanently supplied to the combustion catalyst 28 even after the oxidation reaction has started, problems caused by the excess air, such as a decrease in the temperature of the iron tip 12, become a problem.

However, in the case of flameless combustion using the combustion catalyst 28, more complete combustion can be obtained by slightly increasing the amount of air than in the case of normal flaming combustion, so there is no particular problem, and the amount of air is too large. If a decrease in the temperature of the iron tip 12 is expected, an adjustment ring is provided on the outer periphery of the mixed gas generation metal pipe 15, and this adjustment ring is used to reduce the opening area of the air suction hole 20 after flameless combustion starts. There is no particular problem if you do this.

Therefore, the combustion catalyst 2 is caused by the unstable flame 30.
8 can be heated to the oxidation reaction temperature, and the flame can be automatically extinguished at the same time that flameless combustion is started in the combustion catalyst 28.

In the above embodiment, the case where the soldering iron tip 12 is a contact type soldering iron tip was explained, but as shown in FIG. 5, the combustion exhaust gas from the combustion catalyst 28 is discharged as hot air from the discharge port 32a at the tip. The present invention can be similarly applied to the case of a non-contact type soldering iron tip 32, and the same effects as in the above embodiment can be expected.

Further, in the above embodiment, the case where only the cylindrical combustion catalyst 28 having square-shaped partitions inside was used, but due to variations in the product etc., the flame 3
It is conceivable that the time during which 0 is occurring becomes extremely short, and in this case, it is expected that flameless combustion will not necessarily be started with one ignition operation.

FIG. 6 shows an ignition catalyst 38, which is made to deal with such a situation, and is made by supporting a catalyst on a cotton-like or fibrous carrier having high heat resistance at the base end of the combustion catalyst 28. It is arranged.

Since the cross-sectional area of the carrier is extremely small, the ignition catalyst 38 is quickly and reliably heated to the oxidation reaction temperature even with an extremely short flame, and the flameless combustion heat here ensures that at least the proximal end of the combustion catalyst 28 is heated. can be heated up to the oxidation reaction temperature. Therefore, flameless combustion can be reliably started with a single ignition operation. Note that the combustion catalyst 28 is omitted,
The entire structure may be made up of only the ignition catalyst 38.

〔Effect of the invention〕

As explained above, the present invention ignites excess air mixed gas to cause unstable short-term flaming combustion in the ignition tube, and uses the combustion heat to heat at least the base end of the combustion catalyst to the reaction temperature. This makes it possible to incorporate an automatic ignition mechanism with a simple device configuration, and in addition, after the combustion catalyst reaches the reaction temperature, the flame is automatically extinguished and the entire amount of mixed gas is burned flamelessly with the combustion catalyst. can be done. Therefore, there is no risk of flames being generated outside the iron, and furthermore, an improvement in thermal efficiency can be expected.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts showing one embodiment of the present invention;
Fig. 2 is an external view showing the overall configuration, Fig. 3 is an enlarged perspective view of the combustion catalyst, Fig. 4 a, b, and c are explanatory diagrams sequentially showing the process from ignition to flameless combustion, and Figs. FIG. 6 is a sectional view showing other embodiments of the present invention. 1... Gas tank, 2... Handle, 5... Outlet valve, 10... Outer case, 12, 32... Soldering tip,
15...Mixed gas generation metal pipe, 16...Mixed gas derivation metal pipe, 17...Orifice, 18
... Filter, 19 ... Air port, 20 ... Air suction hole, 21 ... Ignition tube, 22 ... Piezoelectric spark plug, 25 ... Piezoelectric ignition element, 28 ... Combustion catalyst,
29... Peephole, 30... Flame, 38... Ignition catalyst.

Claims (1)

[Scope of Claims] 1. A gas ejector that ejects fuel gas and an ejector action of the gas injected from the gas ejector, which is provided on the outlet side of the gas ejector, are used to generate an excessive amount of gas than in normal flaming combustion from the outside. A cylindrical mixed gas generating section that sucks air to generate excess air mixed gas, and an open-ended cylindrical ignition that is provided at the tip of this mixed gas generating section and has a larger cross-sectional area than the mixed gas generating section. a soldering iron tip disposed at the tip of the ignition tube and having a combustion catalyst built therein for flamelessly burning the mixed gas; and a piezoelectric ignition plug disposed within the ignition tube; Excess air mixed gas discharged from the generation section is ignited by a piezoelectric ignition plug to cause unstable short-term flaming combustion within the ignition tube, and the combustion heat causes at least the base end of the combustion catalyst to react. A thermal processing device that uses liquefied gas to heat up to a certain temperature. 2. Claim 1, wherein the ignition tube is made of a translucent electrical insulating material.
A thermal processing device using liquefied gas as described in 1. 3. The liquefied gas according to claim 1 or 2, wherein the combustion catalyst has an ignition catalyst formed by supporting the catalyst on a fibrous carrier at least at its base end. Thermal processing equipment used. 4. Using the liquefied gas according to claim 1, 2, or 3, wherein the soldering iron tip is a contact type soldering iron tip that is heated by the heat of combustion in a combustion catalyst. Thermal processing equipment. 5. The iron tip according to claim 1, 2 or 3, wherein the iron tip is a non-contact type iron tip that discharges combustion exhaust gas from the combustion catalyst as hot air from the tip. A thermal processing device using liquefied gas.