JPH0328621A - Combustion device - Google Patents

Abstract

PURPOSE:To contrive the miniaturization and noise control of a combustion device by placing a neutralizer on the bottom part of a fan casing to provide a drain device on the lowest part so as to communication an exhaust passage and the fan casing each other in the combustion device such as a hot water supply machine. CONSTITUTION:A great part of exhaust gas which burns in a furnace 13 to radiate in a heat exchanger 14 is collected in an exhaust hood 15 to release from an exhaust top 16. On the other hand, the residual exhaust gas is allowed to flow in a communicating pipe 21 to suck in a fan casing 23 by the use of negative pressure suction action produced by a rotating fan 10. And the exhaust gas is mixed with fresh air to supply to a burner 11 again. And combustion becomes slow by inactive gas and water vapor in the exhaust gas and the heat capacity of combustion gas increases to lower flame temperature. Accordingly, the production of NOx can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a combustion system of a domestic combustion device such as a water heater or a space heater, and particularly to a device for suppressing the production of nitrogen oxides.

BACKGROUND OF THE INVENTION Conventionally, this type of combustion equipment has been applied to large industrial boilers as shown in Figure 4. That is, the re-W4 ring passage 2 is provided by branching from the middle of the exhaust passage 1,
A relay fan 3 for transporting exhaust gas and a damper 4 for flow rate adjustment were installed along the way. The recirculated exhaust gas is mixed with fresh combustion air supplied from the blower fan 5, and is sent to the burner 7 together with fuel supplied from the fuel supply pipe 6, where it is combusted in the combustion chamber 8 and generates heat. After passing through the exchanger 9, it became exhaust gas and was released into the weather through the exhaust passage l. Here, the recirculated exhaust gas flow rate was controlled by the damper 4 so as to maintain stable combustion in response to various operating conditions of the boiler and to minimize the production of nitrogen oxides.

The invention attempts to solve a! However, in such a horizontal combustion apparatus, a plurality of fibers are required. In addition, a motor is required to drive the damper in order to adjust the flow rate of the re-circulated exhaust gas. Therefore,
Up until now, the combustion equipment had become larger, louder, and more expensive, and the corrosion of the inside of the combustion chamber and the fan due to the acidic water vapor during exhaust gas recirculation had made it difficult to use at home. It could not be used as a commercial combustion device.

Therefore, the present invention aims to simplify the exhaust gas recirculation system, downsize the combustion device, prevent an increase in noise, and further reduce costs. Means for Solving the Problems - In order to solve the problems described in E, the combustion apparatus of the present invention includes a fan installed at the lowest part to supply air to the burner, a burner on two vertical sides of the fan, and a combustion chamber. and a heat exchanger.
Exhaust passages are provided in close contact with each other in sequence, a connecting pipe is provided between the exhaust passage and the fan, the opening end on the fan side of the connecting pipe is opened into the casing of the fan, and the opening end of the connecting pipe on the fan side is opened into the casing of the fan. A neutralizing agent is placed at the bottom, and a water drainage device is installed at the bottom of the fan casing. Operation: The combustion system of the present invention has the structure described in E. When the fan is driven, a negative pressure region is generated near the fan suction port. Since the open end of the connecting pipe is provided near the fan suction 1'', when this negative pressure region is generated, the gas inside the connecting pipe will be drawn toward the fan. Since one end of the connecting pipe is connected to the exhaust passage, a part of the combustion exhaust gas flowing through the exhaust passage is guided to the fan through the connecting pipe, and is supplied to the burner while being combined with fresh air by the fan. It will be cleaned. This makes it possible to create a +11 air recirculation system without providing a new drive.

Additionally, because the opening end of the connecting pipe on the fan side is fixed to the fan casing, the exhaust gas from the connecting pipe will not leak outside the combustion section even in strong winds or when the fan starts or stops. Therefore, corrosion of the outer wall surface of the appliance and corrosion of the control circuit due to the exhaust gas can be prevented.

In addition, the recirculated exhaust gas contains acidic water vapor, which condenses inside the fan casing and accumulates at the bottom of the casing. However, by placing a neutralizing agent inside the fan casing and also installing a drainage device at the bottom of the casing, it is possible to neutralize the acidic condensation water that accumulates inside the casing due to the fan air pressure when the fan is operated. It can be discharged outside the device afterwards.

Embodiment Hereinafter, a case where an embodiment of the present invention is applied to a water heater will be explained based on the attached circle.

In Figures 1 to 3, the fan l installed at the bottom
On the vertical side of O - E, there is F' with burner Ik water pipe l2 wound around it.
Ram 2 combustion chamber 13, fin pipe heat exchanger 14,
An exhaust hood 15 that collects exhaust gas and an exhaust top l6 that forms an exhaust outlet are successively connected to each other in an airtight manner. A gas bronch 17 having a function of adjusting the flow rate of gas fuel is connected to the burner 11. A water filter 18 having a function of adjusting the amount of water entering is connected to the water inlet on the upstream side of the water pipe 12. Further, a hot water outlet pipe 19 is connected to the outlet of the heat exchanger 14, and a control block 20 is housed on the side of the main body of the water heater. Here, one end of the connecting pipe 2L is connected to the side of the exhaust hood 15, which is a part of the exhaust passage.

On the other hand, the other end of the connecting pipe 21 is fixedly installed in the fan casing 23 at a position near the intake port 22 of the fan 10 where a negative pressure region is generated. Further, a neutralizing agent 24 is disposed at the bottom of the casing 23 of the fan 10, and a wandering water device 25 is provided at the lowest part of the casing 23.

Next, the operation of the configuration of this embodiment will be explained. When the hot water tap is opened and water begins to flow through the main body of the water heater, water flow is detected within the water block 18, and the fan 10 is driven by a command from the control block 20 to supply combustion air to the burner 1L. Ru. The flow rate of the primary fuel is determined by the control block 20 according to the hot water supply load, and the gas block 17
After being controlled by , it is supplied to burner 1l. The supplied air and fuel are combusted in the combustion chamber 13 by the Pana 11, and become highly profitable combustion exhaust gas, which reaches the heat exchanger 14. Here, the water that has passed through the water bath 18 and the water pipe 12 is heated in the heat exchanger 14 by high-temperature exhaust gas, becomes hot water, passes through the hot water outlet pipe 19, and is supplied for hot water supply. On the other hand, most of the low-temperature exhaust gas from which heat has been removed is transferred to the exhaust hood 15.
is collected and released into the atmosphere from the haiku tonopu l6.

Here, a part of the exhaust gas in the exhaust hood 15 is transferred to the connecting pipe 21.
Ni'! Ilt is included.

On the other hand, when the fan IO is driven, a negative pressure region is generated near the fan intake port 22. The inside of the casing 23 also becomes a negative pressure region near the fan intake port, and the end of the connecting pipe 21 is also included in the negative pressure region. Therefore, due to this negative force, the exhaust gas in the wandering hood 15 enters the fan 10 through the connecting pipe 2l, is uniformly mixed with fresh combustion air in the casing 23, and is supplied to the burner 11 again. The inert gases and aquatic plants contained in the salmon in the exhaust gas cause slow combustion, and the heat capacity of the combustion gas increases, which lowers the flame temperature by 1.5 degrees and suppresses the production of nitrogen oxides. Ru.

Further, the recirculated exhaust gas contains acidic water vapor, and when the water vapor is sucked into the fan 10 side, dew condenses within the casing 23 of the fan 10 and accumulates at the bottom of the casing 23. This dew condensation water is neutralized by a neutralizing agent 24 such as magnesium provided inside the casing 23 of the fan 10, and then drained out of the appliance via a drainage device 25 by the air blowing pressure when the fan 10 is driven.

FIG. 3 shows the exhaust gas characteristics with and without IF gas recirculation.

By appropriately setting the pipe diameter and excess air ratio of the communication pipe 2L, the CO generation characteristics will deteriorate slightly, but the production of nitrogen oxides will remain low, and the noise level will increase at the same time.
It can be controlled.

Effects of the Invention As is clear from the above explanation, the combustion bag device of the present invention provides the following effects.

(1) Since an exhaust re-shield ring system is constructed by branching from the middle of the air passage and providing a communication pipe near the fan's intake port, a new power source is not required, noise is suppressed, and nitrogen oxides are removed. can be achieved.

(2) Since the method involves creating a new exhaust recirculation system by installing a new communication pipe that branches off from the middle of the exhaust route, it can be easily applied to existing combustion equipment, and the manufacturing process is also simple. (3) Since the opening end on the fan side of the connecting pipe is installed in the fan casing, the exhaust gas from the connecting pipe is routed to the outside of the combustion equipment even in strong winds or when the fan starts or stops. This prevents condensation and corrosion on the outer wall of the device, as well as condensation and corrosion on the control circuit.

(4) A neutralizing agent is placed inside the fan casing, and a drainage point is provided at the bottom of the fan casing, so acidic water vapor condensed inside the fan casing is neutralized and then removed when the fan is operated. The condensed water accumulated inside the fan can be used to prevent corrosion of the fan casing since it is discharged outside the device due to the calming pressure present in the fan. Also,
Since water is drained outside the device after neutralization, damage to the ring around the device installation can be prevented.

[Brief explanation of drawings]

Fig. 1 is an overall perspective view with some parts missing when an embodiment of the present invention is applied to a water heater, Fig. 2 is a partial sectional view showing the main parts near the fan suction port in Fig. 1, and Fig. 3 The figure is a comparative explanatory diagram showing combustion performance with and without exhaust gas recirculation, and FIG. 4 is an overall configuration diagram of a conventional example. lO...Fan, l1...Burner, 1
3... Combustion chamber, 14... Heat exchanger, l
5...IN air hood, 16...Haikyu top, 2l...Connecting pipe, 22...F, / suction port, 23...・Fan casing, 24・
...neutralizer, 25...{11 Water device.

Claims (1)

[Claims] A fan installed at the bottom that supplies air to the burner,
A burner, a combustion chamber, a heat exchanger, and an exhaust passage are provided vertically above the fan in close contact with each other, a connecting pipe is provided between the exhaust passage and the fan, and an open end of the connecting pipe on the fan side is provided. A combustion device, wherein a part is opened in a casing of the fan, a neutralizing agent is disposed at the bottom of the casing of the fan, and a drainage device is provided at the lowest part of the casing of the fan.