JPS6317962Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a water heater that uses gas, oil, etc. as fuel.

Conventional Structure and Problems Conventionally, as shown in FIG. 1, water heaters have been developed that aim to improve efficiency by condensing water vapor in combustion exhaust gas. This is achieved by further arranging the second heat exchanger 6 above the heat exchanger (first heat exchanger 4) that surrounds the burner 1.
Although the aim was to increase the heat transfer area of the heat exchanger 6 and achieve high efficiency, condensed water came out in the second heat exchanger 6 because the water vapor in the combustion exhaust gas condensed.
Since this condensed water is acidic with a pH of 3 to 4, it must be neutralized with Mg or the like before being discharged outside the machine. The pH becomes acidic due to the presence of a large amount of NOx in the combustion exhaust gas, and unless this NOx is reduced, the condensed water will not become neutral.
Furthermore, since the second heat exchanger is disposed downstream after combustion is completed, there is a problem in that the overall size becomes large.

Purpose of the invention The present invention is intended to solve the above-mentioned conventional problems, and aims to increase the heat exchange efficiency and neutralize the condensed water of the water vapor in the exhaust gas.

Structure of the invention In order to achieve the above object, the water heater of the present application is provided with a first combustion chamber and a first heat exchanger to separate the combustion chambers into two combustion chambers downstream of the burner, and a first combustion chamber and a first heat exchanger are provided downstream of the first heat exchanger. has a configuration in which a second combustion chamber having a secondary air intake and a second heat exchanger are arranged, a condensed water receiver is provided below the second heat exchanger, the combustion section is separated into two stages, and the combustion section is separated into two stages. The first stage of the part is configured to perform combustion in the burner, and the second stage is configured to perform combustion in a second combustion chamber downstream of the first heat exchanger, increasing heat exchange efficiency by condensing water vapor in the combustion exhaust gas,
By reducing NOx in the combustion exhaust gas, the PH of the condensed water can be made neutral, and the neutralizing agent can be removed.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, a burner 1 is designed to burn downward, and the combustion chamber of the burner 1 is divided into a first combustion chamber 2 and a second combustion chamber 3. First combustion chamber 2
is attached to the burner 1 on one side, and the first heat exchanger 4 is attached on the other side. A second combustion chamber 3 having a secondary air intake port 5 is located downstream of the first heat exchanger 4, and a second heat exchanger 6 is installed downstream of the second combustion chamber 3. On the downstream side of the second heat exchanger 6, there is a condensed water receiver 7 and an exhaust fan 8. The water to exchange heat with the combustion gas passes through the second heat exchanger 6 from the water supply port 9,
Thereafter, the water flows from the first heat exchanger 4 to the hot water supply port 10 .

Next, in the above configuration, a mixture of gas and air is combusted in the burner 1, but in the first combustion chamber 2, the amount of air given to the gas is less than the theoretical air amount, and the rest is in the first combustion chamber 2. 2 combustion chamber 3
In order to obtain a predetermined excess air ratio, air is taken in through the secondary air intake port 5, and combustion is performed using the first heat exchanger 4 as a flame port. The first heat exchanger 4 exchanges heat mainly with sensible heat in the combustion exhaust gas, and heats the water flowing therethrough. Further, downstream from the first heat exchanger 4, the sensible heat and latent heat in the combustion gas combusted in the second combustion chamber 3 are transferred to the second combustion chamber 3.
The heat exchanger 6 exchanges heat and heats the water flowing in from the water supply port. At this time, if condensed water comes out from the second heat exchanger 6, the condensed water is discharged from the condensed water receiver 7 to the outside of the machine. If a premixture with a combustion form below the stoichiometric air amount is supplied, NOx will normally be large, but in this invention, the combustion section is separated into two stages, so the combustion temperature is lowered and NOx generation is reduced. being held down,
The pH of the condensed water becomes neutral and can be discharged directly from the machine. On the other hand, if a well-known combustion form is supplied with a premixture in excess of the theoretical air amount,
The secondary air intake port 5 is not required, and similarly, the first heat exchanger 4 exchanges mainly sensible heat, and the second heat exchanger 6 exchanges both sensible heat and latent heat. In this case, the production of NOx is suppressed by all primary combustion. or,
After heat exchange in the first heat exchanger 4, the second combustion chamber 6
A high-temperature zone is created again, and the residence time of the combustion exhaust gas increases, which accelerates CO oxidation and suppresses CO production.

Effects of the invention As described above, the present invention separates the combustion section into two stages, each with a heat exchanger and a combustion chamber, and uses the first heat exchanger to replace the flame hole in the second stage. 1 The flame temperature is lowered by the cooling effect of the heat exchanger.
The generation of NOx can be suppressed, and the condensed water whose latent heat has been recovered by the second heat exchanger can be made neutral, so there is no need to install a neutralizing agent such as Mg. Furthermore, since the CO generated in the second combustion chamber downstream of the first heat exchanger is oxidized and complete combustion is promoted, the entire device can be made more compact.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional water heater, and FIG. 2 is a block diagram of a water heater that is an embodiment of the present invention. 1... Burner, 2... First combustion chamber, 3... Second
Combustion chamber, 4...first heat exchanger, 5...secondary air intake, 6...second heat exchanger, 7...condensed water receiver.

Claims (1)

[Scope of utility model registration request] A first combustion chamber and a first heat exchanger are provided downstream of the burner, and a second combustion chamber and a second heat exchanger are provided downstream of the first heat exchanger.
A heat exchanger is arranged, a condensed water receiver is provided downstream of the second heat exchanger, and the combustion section formed by the burner is separated into two stages, and the first stage of the combustion section is connected to the burner. The second stage is a water heater formed in the first heat exchanger.