JPH0351619Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a water heater that improves hot water efficiency by providing a heat-resistant air-permeable solid serving as a ventilation resistor in a combustion cylinder.

(Conventional technology) Conventionally, this type of water heater
There is a publication number.

The above publication constructs a surface combustion burner by constructing a porous metal with a cooling pipe along the mixture formed at the bottom of the combustion cylinder, and also provides a ventilation resistor above the surface combustion burner. A combustion chamber is formed between the combustion burner and the ventilation resistor, and a heat exchanger made of a finned spiral tube is installed adjacent to the ventilation resistor, which allows for the miniaturization of the device by shortening the flame. At the same time, the sensible heat possessed by the combustion gas is converted into radiant energy by the ventilation resistor to form a strong radiant field, which acts on the heat exchanger by adding radiant heat transfer to forced convection heat transfer. This makes it possible to increase heat transfer efficiency.

(Problem that the invention aims to solve) However, in the case where the ventilation resistor is installed in this way, the main part of the radiant energy is directed upstream, that is, toward the combustion chamber, and as a result, the inside of the combustion chamber becomes extremely high temperature. Therefore, in the conventional type described above, the burner surface is cooled by the cold water flowing in the cooling pipe along the surface, so although there is no problem, the surrounding wall of the combustion chamber, which does not have any protection means, It is damaged by exposure to high temperatures and its durability is compromised.

Moreover, in the above-mentioned conventional water heater, the surface combustion burner is made of porous metal made of combustion metal, so the premixed gas flows from the mixing chamber unevenly.
It is difficult to obtain uniform combustion. Since cold water is passed through the cooling pipe that runs along the porous metal, the combustion surface may be cooled more than necessary, which may impair complete combustion. Since the heat exchanger is disposed close to the ventilation resistor, the exhaust gas that passes through the heat exchanger and is exhausted remains at a high temperature, resulting in not only a large heat loss but also a safety problem.

The present invention was developed in view of the above-mentioned problems of the conventional technology, and its purpose is to solve the above-mentioned problems at once, to provide excellent durability and safety, to ensure complete combustion, and to improve hot water efficiency. Our goal is to provide high quality water heaters.

(Means for Solving the Problems) In order to solve the above problems, the water heater of the present invention has a combustion chamber formed at the bottom of the combustion cylinder, which introduces fuel gas and all the air necessary for combustion, and premixes them. A surface combustion burner consisting of a mixing chamber and a wire mesh with a cooling pipe installed over the mixing chamber and connecting the cooling pipe outlet to the hot water supply pipe; A ventilation resistor installed at a required distance from the burner, a combustion chamber defined between the surface combustion burner and the ventilation resistor and provided with a heat insulating layer along the inner peripheral wall surface, and a combustion chamber above the ventilation resistor. A heat exchanger is installed at an appropriate distance from the ventilation resistor and its inlet is connected to a water supply pipe, and piping is installed along the outer peripheral surface of the combustion cylinder between the heat exchanger and the ventilation resistor. and a water pipe connecting the heat exchanger outlet to the cooling pipe inlet.

(Function) In the water heater configured as described above, the premixed gas is uniformly supplied to the surface of the wire mesh through the wire mesh, and is combusted uniformly on the wire mesh surface without unevenness. The inside of the combustion chamber becomes high in temperature due to the radiant heat of the ventilation resistor, but this heat is insulated by the heat insulating layer and is not directly transmitted to the peripheral wall of the combustion chamber.

In addition, the water flowing inside the cooling pipe cools the wire gauze and protects it from damage due to high temperatures, and the premixed gas passing through the wire gauze has a temperature lower than the ignition temperature at the point where it passes, thereby preventing backfire. However, since the water flowing through the cooling pipe is hot water heated by a heat exchanger, the premixed gas is not cooled more than necessary.

Furthermore, the heat of the combustion gas that has passed through the ventilation resistor is recovered by the water flowing through the water pipes before reaching the heat exchanger.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

This embodiment uses a surface combustion burner, in which the fuel gas and all the air necessary for combustion are introduced into a mixing chamber 6 formed at the bottom of the combustion tube 5, where they are mixed.
A premixed gas formed by mixing this fuel gas and combustion air is transferred to a mixing chamber 6 corresponding to the downstream side of the mixing chamber 6.
The premixed gas is raised through a wire mesh 7 provided on the upper side, and the premixed gas is combusted in a planar manner near the top surface of the wire mesh 7.

The combustion tube 5 is formed into a box shape with an open top, and the top opening is integrally equipped with an exhaust hood 9 having an exhaust port 8 opened in the front.

Further, the combustion tube 5 has an air supply port 10 at its bottom, and a gas supply port 11 for blowing fuel gas into the air supply port 10 from the surrounding area.

Inside the combustion tube 5, a wire mesh 7 is disposed above the bottom surface having the air supply port 10 and the gas supply port 11 at an appropriate distance from the bottom surface. A mixing chamber 6 for premixing the fuel gas and all the air necessary for combustion is formed between the two, and a ventilation resistor 2 is provided in an erected manner at a not-too-large distance above the wire mesh 7.
A combustion chamber 3 is formed between the wire mesh 7 and the wire mesh 7.

Thus, the mixing chamber 6, the wire mesh 7, and the combustion chamber 3
A surface combustion burner 1 is formed by this.

That is, the fuel gas supplied from the gas supply port 11 and all the air necessary for combustion supplied from the air supply port 10 are sufficiently premixed in the mixing chamber 6, and this premixed gas passes through the wire mesh 7 and is combusted. The ignition device 1, such as an igniter, flows upward into the chamber 3 and is installed in the chamber 3.
2, it is ignited and burns in a planar shape on the upper surface of the ventilation wire mesh 7.

The cooling pipe 13 is fixed to the upper surface of the wire mesh 7 mentioned above.

The ventilation resistor 2 is a solid plate made of a heat-resistant material, such as ceramic, and is provided with a large number of holes through which combustion gas can pass upward.
It is heated and scorched by the combustion of the burner 1, and the radiant heat makes the inside of the combustion chamber 3 high temperature to accelerate the combustion speed and prevent the occurrence of the lift phenomenon.

The combustion chamber 3 has a heat insulating material layer 4 along the inner surface of its peripheral wall.
will be established.

The heat insulating material layer 4 is made of a heat-resistant insulating material such as ceramic fiber formed into a rectangular cylindrical shape with both upper and lower sides open. The layer 4 is inserted and fitted into the combustion chamber 3, and is surrounded by the ventilation resistor 2 and the wire mesh 7 from above and below. It is held in place and its outer circumferential surface abuts against the inner circumferential surface of the combustion chamber 3 .

On the other hand, above the ventilation resistor 2, a fin heat exchanger 14 is installed inside the combustion tube 5 with an appropriate distance from the ventilation resistor 2. A water pipe 1 is installed on the outer peripheral surface of the peripheral wall of the combustion cylinder 5 between
5 is wound.

The water pipe 15 has an upstream end connected to the fin heat exchanger 14
The downstream end is connected to the hot water supply pipe 16, and the middle part is connected to the cooling pipe 13.

Note that the inlet of the fin heat exchanger 14 is connected to the water supply pipe 17.
connected to.

The cooling pipe 13 cools the wire mesh 7 with water flowing inside to protect it from damage due to high temperatures and also prevents the temperature of the wire mesh 7 from rising. This prevents backfire by keeping the temperature low, and also connects the water pipe 15 to the hot water supply pipe 16.
It also functions as a heat exchanger to heat the flowing hot water.

(Effects) Since the present invention has the above configuration, it has the following advantages.

(1) Since a heat insulating material layer is provided along the inner surface of the peripheral wall of the combustion chamber, even if the combustion chamber becomes extremely hot due to the radiant heat of the ventilation resistor, the peripheral wall of the combustion chamber is protected from the high temperature. Damage can be prevented.

(2) Since a heat insulating material layer is provided along the inner surface of the peripheral wall of the combustion chamber, heat radiation from the peripheral wall of the combustion chamber is prevented and heat loss is reduced.

(3) Since a surface combustion burner is constructed by installing a wire mesh above the mixing chamber, the premixed gas can be uniformly supplied to the combustion surface, eliminating uneven combustion and burning in a uniform surface. .

Therefore, the flame can be reliably shortened, and the device can be made smaller.

(4) Since hot water heated by a heat exchanger flows through the cooling pipes that run along the wire mesh, there is no possibility of overcooling the premixed gas passing through the wire mesh or the wire mesh, thereby inhibiting complete combustion.

(5) The heat exchanger was installed to be separated from the ventilation resistor for an appropriate amount of time, and a water pipe connecting the heat exchanger outlet and the cooling pipe inlet was wound around the combustion cylinder peripheral wall between the two.
Heat can be recovered from the combustion gas that has passed through the ventilation resistor using both the water pipe and the heat exchanger, and the heat can be exhausted.
Not only does it reduce heat loss and improve hot water efficiency, but it is also safer because the exhaust gas temperature is lower.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a water heater showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional side view. DESCRIPTION OF SYMBOLS 1... Burner, 2... Ventilation resistor, 3... Combustion chamber, 4... Heat insulation layer, 5... Combustion cylinder, 6... Mixing chamber, 7... Wire mesh, 13... Cooling pipe, 14... ...Heat exchanger, 15...Water pipe, 16...Hot water pipe, 17...
...Water pipe.

Claims (1)

[Scope of utility model registration request] a mixing chamber formed at the bottom of the combustion cylinder, which introduces fuel gas and all the air necessary for combustion and premixes them;
A surface combustion burner is constructed by installing a wire mesh with a cooling pipe along it over the mixing chamber, and the cooling pipe outlet is connected to the hot water supply pipe. a combustion chamber defined between the two by a surface combustion burner and the ventilation resistor and provided with a heat insulating layer along the inner circumferential wall surface; A heat exchanger is installed at an appropriate distance from the resistor and its inlet is connected to a water supply pipe, and piping is installed along the outer circumferential surface of the combustion cylinder between the heat exchanger and the ventilation resistor, and the heat exchanger is installed at an appropriate distance from the resistor. A water heater comprising a water pipe connecting an exchanger outlet to a cooling pipe inlet.