JPH08121702A - Steam generator - Google Patents

Abstract

PURPOSE: To improve the combustion characteristic, combustion controllablility and steam producting efficiency by constituting a steam passage between a steam chamber and a steam nozzle in such a manner as to be surrounded by an exhaust passage of a combustion chamber in a steam generator used for an inhaler, a humidifer and the like which utilize heat obtained by combustion. CONSTITUTION: The steam generator gasifies liquefied gas in a fuel tank 19 by means of a gas nozzle 21 to jet gas, and the jet of the fuel gas is mixed with air by means of a mixing device 23 before being fed to a combustion chamber 14. By utilizing combustion heat generated by a catalyst 24 within the combustion chamber 14 water supplied from a water tank 11 is evaporated in a steam chamber 13 and steam is jetted through a steam nozzle 17. A steam pipe 15 extending from the steam chamber 13 to the steam nozzle 17 and an accumulator 16 are disposed in such a manner as to be surrounded an exhaust chamber 27. The steam pipe 15 and the accumulator 16 are heated by combustion gas of high temperature so that steam generated in the steam chamber 13 is prevented from being condensed to improve steam generating efficiency.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam generator used in an inhaler, a humidifier, etc., which utilizes heat obtained by catalytically burning a liquefied fuel gas.

2. Description of the Related Art A conventional steam generator has a structure as shown in FIG. Water for steam generation is stored in the water tank 1. The water in the water tank 1 is supplied to the steam chamber 3 via the water supply pipe 2. A heater 4 is provided on the wall surface of the steam chamber 3, and the water in the steam chamber 3 is heated by the heater 4 to become steam. The high-pressure steam generated in the steam chamber 3 passes through the steam pipe 5 and the accumulator 6 and is ejected from the steam nozzle 7. The steam chamber 3 and the water tank 1 are connected by a communication pipe 8, and the pressure in the steam chamber 3 acts on the water tank 1 so that water can be smoothly supplied from the water tank 1 to the steam chamber 3. There is.

The conventional steam generator uses an electric heater as a heating source. Electric power consumption of several hundred watts is required to generate steam, and it is difficult to use dry batteries or accumulators, and a power cord is indispensable. For this reason, there are problems that the place to use is limited and the usability is poor. Although the above problems can be solved by using the combustion heat of liquid fuel gas or the like as the heating source, good combustion characteristics and combustion control are difficult, and steam generated in the steam chamber is supplied to the steam nozzle. However, dew condensation occurs in the steam passage, which causes a new problem that the efficiency of steam generation is reduced. It is an object of the present invention to provide a steam generator capable of solving the above-mentioned problems of the prior art and having excellent combustion characteristics, combustion controllability, and steam generation efficiency.

According to a first aspect of the present invention, a fuel tank for storing liquefied fuel gas, a gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, and a fuel gas and air ejected from the gas nozzle are provided. A mixing device for mixing, a combustion chamber to which a mixed gas is supplied, a catalyst arranged in the combustion chamber, a water tank for storing water for steam generation, and a combustion heat generated by the catalyst from the water tank. A steam chamber for evaporating water and a steam nozzle for ejecting steam generated in the steam chamber are provided, and a steam passage formed between the steam chamber and the steam nozzle is surrounded by an exhaust passage of a combustion chamber. A second invention of the present application is a fuel tank for storing liquefied fuel gas, a gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, and a gas flow rate adjusting means arranged between the gas nozzle and the fuel tank.
A mixing device that mixes air with fuel gas ejected from a gas nozzle, a combustion chamber to which the mixed gas is supplied, a catalyst arranged in the combustion chamber, a water tank for storing water for steam generation, and a catalyst generated A steam chamber that evaporates the water supplied from the water tank by the heat of combustion and a steam nozzle that ejects the steam generated in the steam chamber.The steam chamber is installed on the wall surface of the combustion chamber, and the combustion chamber faces the steam chamber. A temperature detecting section is installed on the wall surface, and the gas flow rate adjusting means is controlled by a signal from the temperature detecting section. A third invention of the present application is a fuel tank for storing a liquefied fuel gas, a gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a gas flow rate adjusting means arranged between the gas nozzle and the fuel tank, and a gas nozzle for ejecting the gas. A mixing device that mixes fuel gas and air, a combustion chamber to which the mixed gas is supplied, a catalyst that is placed in the combustion chamber, a water tank that stores water for steam generation, and water that is generated by combustion heat generated by the catalyst. A steam chamber for evaporating the water supplied from the tank, a steam nozzle for ejecting steam generated in the steam chamber, and a pressure detection unit in the steam chamber are provided, and the gas flow rate adjusting means is controlled by a signal from the pressure detection unit. To do. A fourth invention of the present application is a fuel tank for storing liquefied fuel gas, a gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a mixing device for mixing the fuel gas ejected from the gas nozzle with air, and a mixed gas. The supplied combustion chamber, the catalyst placed in the combustion chamber, the water tank that stores water for steam generation, and the combustion heat generated by the catalyst evaporates the water supplied from the water tank via the water supply channel. It is equipped with a steam chamber and a steam nozzle that ejects the steam generated in the steam chamber, the steam chamber is installed on the wall of the combustion chamber, and the connection on the steam chamber side of the water supply channel is provided near the combustion chamber inlet. is there.

In the present invention, the fuel gas ejected from the nozzle sucks the surrounding air by the attraction of the gas flow, mixes it uniformly in the mixing chamber, and is supplied to the combustion chamber. The mixed gas supplied to the combustion chamber flows in the combustion chamber and comes into contact with the catalyst maintained at a high temperature to perform catalytic combustion. On the other hand, the water in the water tank is supplied to the steam chamber via the water supply pipe. Since the wall surface of the steam chamber and the wall surface of the combustion chamber are connected, the water in the steam chamber is heated by the combustion heat generated in the combustion chamber and becomes steam. High-pressure steam generated in the steam chamber passes through the steam pipe and accumulator and is ejected from the steam nozzle. The steam chamber and the water tank are connected by a communication pipe, and the pressure in the steam chamber acts on the water tank so that water can be smoothly supplied from the water tank to the steam chamber. The combustion gas is released from the exhaust port to the atmosphere, but in the first aspect of the invention, the steam pipe and the accumulator are arranged in the exhaust path from the combustion chamber outlet to the exhaust port. Since the combustion gas has a higher temperature than the steam temperature, there is almost no condensation of the steam during the transportation of the steam from the steam chamber to the steam nozzle, and the steam generation efficiency can be improved. In a combustion device that uses liquid fuel gas filled in a gas cylinder as a fuel, the amount of gas supplied for combustion changes due to changes in the pressure inside the gas cylinder. The pressure change in the gas cylinder depends on the temperature of the gas cylinder. Therefore, the combustion amount changes due to changes in the temperature and changes in the temperature of the gas cylinder due to feedback of combustion heat during use. On the other hand, when water is constantly supplied to the steam chamber from the water tank, steam is generated in proportion to the amount of heat supplied to the steam chamber. Therefore, in order to eject stable steam from the steam nozzle, it is necessary to perform control so that the combustion amount becomes constant. Therefore, in the second invention, the steam chamber is installed on the wall surface of the combustion chamber, and the temperature detecting unit is installed on the wall surface of the combustion chamber facing the steam chamber. Since water is constantly vaporized in the steam chamber, the amount of combustion on the wall of the steam chamber is almost constant regardless of the amount of combustion. For this reason, the temperature of the side wall surface of the steam chamber of the combustion chamber is less likely to be affected by the combustion amount. On the other hand, the wall surface of the combustion chamber facing the steam chamber is unlikely to be affected by the wall temperature of the steam chamber, and therefore the temperature of the wall surface of the combustion chamber changes according to the change in the combustion amount. This temperature change is detected by the temperature detection unit installed on the wall surface of the combustion chamber, and the signal from the temperature detection unit is used to operate the gas flow rate adjusting means to supply the gas to the combustion chamber even if the pressure inside the gas cylinder changes. Since the amount of gas can be made constant, a certain amount of steam can be stably ejected from the steam nozzle. As described above, the wall temperature of the steam chamber is substantially constant without being affected by the amount of combustion in the combustion chamber. On the other hand, since the pressure in the steam chamber changes according to the amount of steam generated, it changes according to the change in the combustion amount. Therefore, in the third invention, this pressure change is detected by the pressure detection unit in the steam chamber provided on the path between the steam chamber and the steam nozzle, and the gas flow rate adjusting means is operated by the signal from the pressure detection unit, whereby the inside of the gas cylinder is operated. Even if the pressure changes, the amount of gas supplied to the combustion chamber can be made constant, so that a constant amount of steam can be stably ejected from the steam nozzle. In such catalytic combustion, the flow velocity of the air-fuel mixture supplied to the combustion chamber is very low, and therefore most of the air-fuel mixture is burned in the upstream portion of the catalyst, and the temperature of the catalyst in this portion becomes high. Therefore, a temperature distribution exists in the combustion chamber in the flow direction. In order to efficiently generate steam, it is necessary to supply water to a place where the temperature of the combustion chamber is high. Therefore, in the fourth invention, the steam chamber is installed on the wall surface of the combustion chamber, and the connection portion on the steam chamber side of the water supply passage is provided near the inlet of the combustion chamber. With such a structure, water is supplied to a portion where the temperature of the catalyst is high, so that steam generation efficiency can be improved.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of an embodiment of the present invention,
The configuration of the first invention will be described below together with the operation. Water for steam generation is stored in the water tank 11. The water in the water tank 11 is supplied to the steam chamber 13 via the water supply pipe 12. The steam chamber 13 is connected to the combustion chamber 14 by a wall surface 14a. The water in the steam chamber 13 is heated by the combustion heat generated in the combustion chamber 14 and becomes steam. The high-pressure steam generated in the steam chamber 13 passes through the steam pipe 15 and the accumulator 16 and is ejected from the steam nozzle 17. Accumulator 1
6 has a function of absorbing pressure fluctuation when steam is generated and realizing stable steam generation. The steam chamber 13 and the water tank 11 are connected by a communication pipe 18, and the pressure in the steam chamber 13 acts on the water tank 11 so that water can be smoothly supplied from the water tank 11 to the steam chamber 13. There is. Liquefied fuel gas such as propane and butane is stored in the gas tank 19. The fuel gas in the gas tank 19 is ejected from the gas nozzle 21 through the gas passage 20. A gas flow rate adjusting valve 22 is provided between the gas tank 19 and the gas nozzle 21 so that the flow rate of the fuel gas supplied from the gas tank 19 can be controlled. The fuel gas ejected from the gas nozzle 21 sucks the surrounding air by the attracting action of the gas flow, uniformly mixes it in the mixing device 23, and the combustion chamber 1
4 is supplied. The combustion chamber 14 is composed of a metal housing,
The catalyst 24 is provided inside, and the air-fuel mixture is burned on the surface of the catalyst 24 to generate combustion heat. A platinum group metal and a metal oxide such as nickel, cobalt, iron, manganese, and chromium are used as the catalyst supported on the catalyst body 24. Particularly preferable are platinum group metals such as platinum, palladium, and rhodium. The fuel gas is supplied from the gas nozzle 21 to the mixing device 23, the air sucked by being attracted to the jetting force of the fuel gas and the fuel gas are mixed by the mixing device 23, and the mixed gas is supplied to the combustion chamber 14. An ignition device 25 is provided on the side of the combustion chamber 14 opposite to the air-fuel mixture inlet, and the spark is blown from the plug at the tip of the ignition device 25 to ignite the mixed gas. The catalytic body 24 is formed by the flame formed downstream of the catalytic body 24.
Is heated and the temperature of the catalyst body 24 reaches the activation temperature,
The catalytic combustion starts on the surface of the catalyst body 24, the mixed gas is not supplied to the flame, and the flame disappears. After that, the combustion chamber 14
The mixed gas supplied into the interior of the combustion chamber 14 is used as the catalyst body 24.
Perform catalytic combustion as a whole. Combustion gas is discharged from the combustion chamber outlet 26 through the exhaust chamber 27 and the exhaust passage 28, and is discharged from the exhaust port 29 to the atmosphere. When the temperature of the combustion chamber 14 rises, the combustion heat generated by the combustion is transferred to the steam chamber 13 via the wall surface 14a. Due to this combustion heat, the water supplied from the water tank 11 becomes steam and is supplied to the steam nozzle 17,
Eject steam into the atmosphere. In the steam path reaching the steam nozzle 17, the high-temperature steam generated in the steam chamber 13 may come into contact with the low-temperature wall surface of the steam path, the temperature of the steam lowers, and dew condensation may occur on the steam path wall surface. When such a phenomenon occurs, it becomes difficult for all the steam generated in the steam chamber 13 to be ejected from the steam nozzle 17, and the steam generation efficiency is significantly reduced. Therefore, in the first invention, the steam chamber 1
An exhaust chamber 27 surrounds the steam path from 3 to the steam nozzle 17, that is, the steam pipe 15 and the accumulator 16. In general, catalytic combustion is performed at a temperature of 300 ° C to 800 ° C, and the boiling point of water is 100 ° C. Therefore, the temperature of the combustion gas discharged from the combustion chamber outlet 26 is higher than the temperature of the steam. It has become. Therefore, as in the present invention, the steam pipe 15 and the accumulator 16 are provided in the exhaust path.
And the like are provided, the wall surfaces of the steam pipe 15 and the accumulator 16 are heated by the combustion gas with the high temperature combustion gas, so that the wall temperature of the path through which the steam passes can be maintained higher than the temperature of the steam. Therefore, the steam generated in the steam chamber 13 does not condense on the way along the path, and almost the entire amount of steam
It can be jetted from 7 liters, and the steam generation efficiency can be significantly improved. Next, the second invention will be described. When a liquefied fuel gas such as propane or butane is filled in a gas cylinder or the like, a liquid phase and a gas phase are mixed. At this time, the pressure in the cylinder depends only on the temperature. The relationship between temperature and pressure in the case of isobutane is shown in FIG. Figure 2
As shown in, when the temperature changes from 10 ℃ to 40 ℃,
The pressure also changes from 2.2 kg / cm ² to 5.5 kg / cm ² . On the other hand, the gas ejection amount q from the nozzle is given by the equation (1). q = 123.1a (h / d) ^1/2 (1) where a is the area of the gas outlet, d is the specific gravity of the gas, and h
Is the gas ejection pressure. Therefore, the ejection amount from the gas nozzle is proportional to the 1/2 power of the pressure in the gas tank. The combustion amount changes at the above-mentioned rate due to a change in temperature and a temperature change in the gas tank due to feedback of combustion heat during use. On the other hand, when water is constantly supplied from the water tank 11 to the steam chamber 13, the amount of steam generated changes in proportion to the combustion heat supplied from the combustion chamber 14 to the steam chamber 13. Therefore, when the combustion amount changes in accordance with the temperature change of the gas tank 11, the steam generation amount also changes. On the other hand, since the boiling point of water is constant at 100 ° C., even if the amount of combustion changes and the amount of steam generated changes, the temperature of the wall surface of the steam chamber becomes almost constant. FIG. 3 shows an example of the relationship between the amount of combustion and the wall temperature of the combustion chamber. The dashed line in the figure shows the temperature characteristics of the wall surface 14a of the combustion chamber connected to the steam chamber 13, and the solid line shows the temperature characteristics of the wall surface 14b of the combustion chamber 14 facing the steam chamber 13. The wall temperature of the combustion chamber wall surface 14a connected to the steam chamber 13 does not change much even if the combustion amount changes, similarly to the fact that the steam chamber is hardly affected by the change in the combustion amount. On the other hand, since the combustion chamber wall surface 14b facing the steam chamber 13 is not in direct contact with the steam chamber 13, it is hard to be affected by the steam chamber 13 and the change of the combustion amount is relatively good, and the change of the wall temperature is relatively good. You can see that it appears as. Therefore, in the second invention, the steam chamber 1 is provided on the combustion chamber wall surface 14a.
3 is installed, and the temperature detecting unit 30 is installed on the combustion chamber wall surface 14b facing the steam chamber 13. The wall surface 14b of the combustion chamber facing the steam chamber 13 is unlikely to be affected by the wall temperature of the steam chamber 13, so that the wall surface 14b of the combustion chamber 14b changes depending on the change in the combustion amount.
Temperature changes. This temperature change is detected by the temperature detection unit 30 installed on the combustion chamber wall surface 14b, and the gas flow rate control valve 22 is operated by the signal from the temperature detection unit 30 to change the pressure in the gas tank 11, Since the amount of gas supplied to the combustion chamber 14 can be made constant, a certain amount of steam can be stably ejected from the steam nozzle 17. Next, the third invention will be described.
As described above, the pressure of the gas tank 11 changes due to the influence of the air temperature and the combustion heat, and the combustion amount changes according to the change amount. Since the boiling point of water is constant at 100 ° C., even if the combustion amount changes, the wall temperature of the steam chamber 13 hardly changes. However, the amount of vapor evaporated in the vapor chamber 13 changes according to the amount of combustion. Since the pressure loss in the steam path from the steam chamber 13 to the steam nozzle 17 is a constant value, the change in the amount of steam corresponds to the change in the pressure in the steam chamber 13. Therefore, the combustion amount can be detected by detecting the pressure in the steam chamber 13. Therefore, in the third invention, this pressure change is detected by the pressure detection unit 31 in the steam chamber 13 provided on the path between the steam chamber 13 and the steam nozzle 17, and the pressure detection unit 3 is detected.
Even if the pressure in the gas tank 11 changes by operating the gas flow rate control valve 22 by the signal from 1,
Since the amount of gas supplied to the combustion chamber 14 can be made constant, a certain amount of steam can be stably ejected from the steam nozzle 17. In this embodiment, the pressure detection unit 31
Is provided in the steam chamber 13, but the steam pipe 15, the communication pipe 18 and the water tank 11 which are related to the pressure in the steam chamber 13 are provided.
The same effect can be obtained by providing the pressure detection unit 31 in the above. Fourthly, the invention will be described. In such catalytic combustion, the flow velocity of the air-fuel mixture supplied to the combustion chamber 14 is very low, and therefore most of the air-fuel mixture is burned in the upstream portion of the catalyst body 24, and the temperature of the catalyst in this portion is high. become. Therefore, a temperature distribution as shown in FIG. 4 exists in the combustion chamber 14 in the flow direction. From this temperature distribution, it can be seen that the catalytic combustion reaction mainly takes place in the upstream portion of the catalyst, and the purifying action becomes predominant from the midstream to the downstream of the catalyst. In order to efficiently generate steam, it is necessary to supply water to a place where the temperature of the combustion chamber 14 is high, that is, a place where the catalytic combustion reaction is mainly performed. Therefore, in the fourth invention, the steam chamber 13 is installed on the combustion chamber wall surface 14a, and the steam chamber side connecting portion 12a of the water supply pipe 12 is provided.
Is provided near the combustion chamber inlet 14c. With such a structure, water is supplied to a portion where the temperature of the catalyst is high, so that steam generation efficiency can be improved.

As is apparent from the above description,
The present invention is provided with a fuel tank for storing liquefied fuel gas, a gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a mixing device for mixing the fuel gas ejected from the gas nozzle with air, and the mixed gas. Combustion chamber, catalyst placed in the combustion chamber, water tank for storing water for steam generation, steam chamber for evaporating water supplied from the water tank by combustion heat generated by the catalyst, and steam chamber Equipped with a steam nozzle for ejecting the generated steam, the steam passage formed between the steam chamber and the steam nozzle is surrounded by the exhaust passage of the combustion chamber, or
A gas flow rate adjusting unit arranged between the gas nozzle and the fuel tank, a steam chamber is installed on the wall of the combustion chamber, a temperature detecting unit is installed on the wall of the combustion chamber facing the steam chamber, and a gas flow rate is generated by a signal from the temperature detecting unit. It controls the adjusting means, and further comprises a pressure detecting section in the steam chamber, controls the gas flow rate adjusting means by a signal from the pressure detecting section, and connects the connection section on the steam chamber side of the water supply passage to the vicinity of the combustion chamber inlet. By providing it, the combustion controllability is improved and stable steam generation is realized.
The steam generation efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a steam generator according to an embodiment of the present invention.

FIG. 2 Correlation diagram of butane gas temperature and pressure

FIG. 3 is a correlation diagram between the combustion amount and the wall temperature of the steam generator according to the embodiment of the present invention.

FIG. 4 is a temperature distribution diagram of a catalyst body of a steam generator according to an embodiment of the present invention.

FIG. 5 is a vertical sectional view of a conventional steam generator.

[Explanation of symbols]

 11 Water Tank 12 Water Supply Pipe 13 Steam Chamber 14 Combustion Chamber 17 Steam Nozzle 19 Gas Tank 21 Gas Nozzle 22 Gas Amount Control Valve 24 Catalyst Body 26 Exhaust Chamber 29 Exhaust Port 30 Temperature Detector 31 Pressure Detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Suzuki, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Within Seiko Co., Ltd.

Claims (4)

[Claims] 1. A fuel tank for storing liquefied fuel gas,
A gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a mixing device for mixing the fuel gas ejected from the gas nozzle and air, a combustion chamber to which the mixed gas is supplied, and a catalyst arranged in the combustion chamber A water tank for storing water for steam generation, and a steam chamber for evaporating the water supplied from the water tank by combustion heat generated by the catalyst,
A steam generator comprising a steam nozzle for ejecting steam generated in the steam chamber, wherein a steam passage formed between the steam chamber and the steam nozzle is surrounded by an exhaust passage of the combustion chamber. 2. A fuel tank for storing liquefied fuel gas,
A gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a gas flow rate adjusting means arranged between the gas nozzle and the fuel tank, a mixing device for mixing the fuel gas ejected from the gas nozzle with air, and a mixed gas Are supplied to the combustion chamber, a catalyst arranged in the combustion chamber, a water tank for storing water for steam generation, and steam for evaporating the water supplied from the water tank by the combustion heat generated by the catalyst. A chamber and a steam nozzle for ejecting steam generated in the steam chamber, the steam chamber is installed on the wall surface of the combustion chamber, and a temperature detection unit is installed on the combustion chamber wall surface facing the steam chamber, A steam generator, wherein the gas flow rate adjusting means is controlled by a signal from a temperature detecting section. 3. A fuel tank for storing liquefied fuel gas,
A gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a gas flow rate adjusting means arranged between the gas nozzle and the fuel tank, a mixing device for mixing the fuel gas ejected from the gas nozzle with air, and a mixed gas Are supplied to the combustion chamber, a catalyst arranged in the combustion chamber, a water tank for storing water for steam generation, and steam for evaporating the water supplied from the water tank by the combustion heat generated by the catalyst. Chamber, a steam nozzle for ejecting steam generated in the steam chamber, and a pressure detection unit in the steam chamber, and the gas flow rate adjusting unit is controlled by a signal from the pressure detection unit. Generator. 4. A fuel tank for storing liquefied fuel gas,
A gas nozzle for vaporizing and ejecting the liquefied gas in the fuel tank, a mixing device for mixing the fuel gas ejected from the gas nozzle and air, a combustion chamber to which the mixed gas is supplied, and a catalyst arranged in the combustion chamber A water tank for storing water for steam generation, a steam chamber for evaporating water supplied from the water tank via a water supply channel by combustion heat generated by the catalyst, and steam generated in the steam chamber A steam generating device comprising a steam nozzle for ejecting the steam, the steam chamber being installed on a wall surface of the combustion chamber, and a connection portion of the water supply passage on the steam chamber side being near the combustion chamber inlet.