JP2003314820A - Exhaust hood for combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust hood for a gas water heater miniaturizing the gas water heater and improving the heat efficiency. <P>SOLUTION: Combustion exhaust air rising after passing through a heat exchanger 6 is once guided rearward and then frontward, and released outdoor from an exhaust port 20, while a part of the combustion exhaust air is fed from the front part to the exhaust port 20 without being once guided rearward, and released outdoor from a hole 25 in a straightening vane 22, so that the combustion gas produced from the burner 4 is made to uniformly pass on the whole surface of the heat exchange fin 7 and exhausted. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust hood for a combustor, and more particularly to an exhaust hood provided above a fin tube type heat exchanger.

[0002]

2. Description of the Related Art As an example of this type of combustor, an outdoor-installed gas water heater is equipped with a combustor that forcibly supplies and exhausts gas because it requires a high hot water supply capacity. Exhaust hood is installed in. FIG. 6A shows an example in which a conventional gas exhaust water heater 60 is provided with a conventional exhaust hood 61. As shown in FIG. 3A, the gas water heater 60
Is equipped with a fin tube type heat exchanger 63 in which a plurality of fins 64 are arranged at intervals, and the heat exchanger 63 is inserted into the heat exchanger 63 by heating the heat exchanger 63 with combustion gas of a burner. This is to heat the water flow of the above and to discharge the hot water.

An exhaust hood 61 for discharging combustion exhaust gas from the gas burner is provided above and behind the heat exchanger 63 so as to cover the heat exchanger 63. The exhaust hood 61 has a substantially rectangular parallelepiped box shape with an open bottom surface, and an exhaust top 68 is provided on the front surface thereof. The exhaust top 68 is formed with an exhaust port 69 whose front surface is entirely or partially opened. Both side walls of the exhaust hood 61 are vertical wall surfaces that are closed to the outside air.

Inside the exhaust hood 61, there are provided a top plate 70 and a current plate 71, which guide all the generated combustion exhaust gas to the rear and then to the front, as indicated by the dotted line arrow. It is formed in a curved shape so as to be discharged to the outside through the exhaust port 69, and as shown in the drawing, the space O on the front side is narrow and the space P on the back side is wide. The rectifying plate 71 is provided to smoothly discharge the combustion exhaust to the outdoors, and the like. The sloping portion 71a that is inclined so as to slightly rise rearward from the front end edge with respect to the horizontal direction, and the sloping portion 71a A bent portion 71b that bends in an arc shape upward from the end and then bends in a curved line until it folds forward to the inclined portion 71a, and horizontally from the end toward the discharge port 69 so as to overlap the inclined portion 71a. It is composed of an inclined portion 71c which is inclined so as to slightly descend.

[0005]

Recently, the body of the device has been made compact, and, for example, the height of the exhaust hood as shown in FIG. A gas water heater 72 was proposed. However, when the size is reduced, the space O becomes too narrow, and the flow of the combustion gas generated from the burner is diverted backward while passing through the fins. There was a problem that the contact with the surface was not good and the thermal efficiency deteriorated. Therefore, it is desired to realize downsizing without lowering the thermal efficiency.

The present invention has been made to solve these problems, and it is an object of the present invention to provide an exhaust hood for a combustor, which can realize miniaturization of the combustor and improve thermal efficiency.

[0007]

In order to solve the above problems, an exhaust hood of a combustor according to claim 1 is provided above a fin tube type heat exchanger heated by combustion gas of a burner, An exhaust hood that discharges the combustion exhaust gas after replacement.The combustion exhaust gas that passes through the heat exchanger and rises is guided backwards and then forwards to escape outside through the exhaust port. Regarding combustion exhaust, it is sent to the exhaust port from the front without being guided to the rear once and allowed to escape to the outside, so that the combustion gas generated from the burner is exhausted by flowing almost uniformly over the entire surface of the heat exchange fins. What is done is the gist.

According to the exhaust hood of the combustor having the above-mentioned structure, the combustion exhaust gas that passes through the heat exchanger and rises is once guided to the rear and then to the front so as to escape to the outside through the exhaust port. However, some of the combustion exhaust gas is sent to the exhaust port from the front and escaped to the outdoors without being guided to the rear. Therefore, the combustion gas generated from the burner is
The heat exchange fins flow through the entire surface of the heat exchange fins substantially uniformly and are exhausted.

In this case, after the combustion exhaust gas after heat exchange is guided rearward by the straightening vanes, it is folded back in a U shape and is guided forward and sent to the exhaust port, and the combustion exhaust gas is rearwardly guided. It is preferable to provide a sub-exhaust flow path that leaks a part of the combustion exhaust gas from the front side portion of the current plate and sends it to the exhaust port.

Then, even if the height of the exhaust hood is low, a part of the combustion exhaust gas leaks from the lower part of the front side of the baffle plate and is sent to the exhaust port, so that the flow of the combustion gas generated from the burner exchanges heat. Does not deviate backwards while passing fins. Therefore, the contact between the combustion gas and the heat exchange fin surface is good even at the front upper side of the heat exchange fin.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 schematically shows the internal structure of a gas water heater to which an embodiment of the present invention is applied. (A) is a front view thereof, and (b) is a side view thereof. FIG. 2 is an external perspective view of the exhaust hood of the gas water heater according to the embodiment of the present invention, and FIGS.
It is the side view, the front view, and the top view, respectively.

In these figures, a forcedly-exhaust type gas water heater 1 installed outdoors is provided with a gas pipe 2 for supplying combustion gas, a water supply pipe 3 for passing water, and a gas burner 4 for burning gas. And an inner shell 5 that surrounds the gas burner 4 and forms a combustion chamber.
And a heat exchanger 6 provided above it, in which a plurality of heat exchange fins 7 are juxtaposed at predetermined intervals, an exhaust hood 8 provided above the heat exchanger 6, and a water supply pipe 3 connected to penetrate the heat exchange fins 7. A heat transfer pipe 9, a hot water supply pipe 10 connected to the heat transfer pipe 9 to communicate with a hot water supply faucet, a blower fan 11 for sending combustion air and urging exhaust air, and a controller 12 for hot water supply control. , A cover body 13 for accommodating the inside of the main body and protecting it from rain and wind.

First, when the water supply pipe 3 extends upward from the lower part of the main body and spirally winds around the inner case 5, the heat transfer pipe penetrates through a plurality of heat exchange fins 7 provided at equal intervals in the heat exchanger 6. After passing through the heat exchanger 6, the heat transfer pipe 9 continues to the hot water supply pipe 10 and extends downward and is connected to the hot water supply connection port 14. Therefore, the gas water heater 1 is heated by the combustion gas generated by the gas burner 4 when water passes through the water supply pipe 3 and the heat transfer pipe 9 of the heat exchanger 6, and then passes through the hot water supply pipe 10 to reach the gas water heater. It is constructed so that it is guided to the outside of the main unit and discharged as hot water in an indoor kitchen or bathroom. The hot water temperature is detected by the thermistor 15. The gas pipe 2 is provided with a source solenoid valve 16 that starts and stops gas supply and a proportional solenoid valve 17 that opens and closes according to the gas supply amount. The hot water temperature, the gas supply amount, the fan rotation speed, and the like are appropriately adjusted by each unit according to a control command from the control unit 12. In the following description, the combustion gas generated from the gas burner 4 is particularly referred to as "combustion exhaust gas" after passing through the heat exchanger.

In the gas water heater 1 having the above structure,
The exhaust hood 8 is provided above the heat exchanger 6 so as to cover it, and discharges the combustion exhaust gas that has passed through the heat exchanger 6 to the outside. The exhaust hood 8 includes a connection frame portion 18 that covers the heat exchanger 6.
An exhaust top 21 provided with a top plate 19 which is above the exhaust path of the combustion exhaust, and an exhaust port 20 for discharging the combustion exhaust.
And a straightening plate 22 that forms the upper and lower sides of the exhaust path of the combustion exhaust,
Side walls 2 standing upright from the side walls of the connecting frame portion 18 so as to face each other.
It consists of 3 mag.

The top plate 19 is continuous with a rear surface portion 19a standing up from a rear surface on the rear side of the connecting frame portion 18 and slightly closer to the front side, and is continued as it is, and is bent forward in a convex arc shape when viewed from the inside of the exhaust hood. The bent portion 19b that descends toward the front side portion 19c that continues from the bent portion 19b and is connected to the exhaust top 21 in a substantially horizontal state is formed of a single metal plate.

The exhaust top 21 includes a top plate 19 and a connecting frame portion 1.
It is attached to the front side of 8 so as to cover them,
The inside is a substantially rectangular parallelepiped hollow. The front end of the straightening vane 22 and the central guide 24 project inside the exhaust top 21, and the central guide 24 gradually extends from both sides in the longitudinal middle of the straightening vane 22 toward the front side. It is provided to be narrow. Further, the exhaust port 20 is formed in a chamfered rectangular shape at the center of the front surface of the exhaust top 21.

The current plate 22 is provided inside the exhaust hood 8 in order to stabilize and uniformize the combustion exhaust flow of the exhaust hood 8 and to improve the thermal efficiency, and is attached by cutting and bending one metal plate material. . The current plate 22 is a rising portion 22a that is bulged from the front side portion of the connecting frame portion 18 and then linearly inclined slightly upward with respect to the horizontal direction.
And a bent portion 22b that continuously bends upward from the end thereof in an arc shape and then curves forward to a portion A extremely close to the rising portion 22a, and a horizontal portion from the end thereof toward the exhaust port 20. Horizontal part 2 that extends in the same direction
2c. And the horizontal part 22c is comprised so that it may become narrow gradually toward the front.

At a portion B of the straightening plate 22 immediately after it is bulged like a bulge, a hole 25 composed of a burring hole whose inner peripheral surface is bulged upward is communicated with the exhaust port 20, and one side wall 23 to the other side. It is formed in two rows at equal intervals up to the side wall 23. Burring holes are used to prevent rain and wind intrusion and pressure loss. The position where the hole 25 is formed is “a position that is substantially right above a site where the combustion exhaust gas is not efficiently heat-exchanged if the hole 25 is not provided”. It is almost directly above the portion indicated by the C portion (corresponding to the O portion in FIG. 6B). Therefore, by providing the hole 25 as the inlet of the combustion exhaust gas, the flow of the combustion gas generated from the burner does not divert backward while passing through the fins.
Even in the portion C, the contact between the combustion gas and the fin surface becomes good.

The central guide 24 is for guiding exhaust gas to the center and guiding it to the exhaust port, and is formed by cutting out a metal plate material and bending it. The central guide 24 is located in the exhaust top 21 inside the exhaust top 21 while gradually approaching a narrow width from both sides in the front view in a state of standing upward from a portion D on both sides in the front view of the horizontal portion 22c and corresponding to a substantially middle portion in the front-rear direction. It extends to just before the exhaust port 20.

The combustion exhaust path is constructed as follows. That is, the top plate 19, the flow straightening plate 22, the central guide 24, the exhaust top 21, and the side wall 23 constitute an upper main exhaust flow path, and the flow straightening plates 22 (22a, 22a).
b, 22c), the exhaust top 21, and the side wall 23 form a lower auxiliary exhaust flow path. The combustion exhaust that has passed through the main exhaust passage is mainly discharged from the upper side of the exhaust port 20 guided by the central guide 24, and the combustion exhaust that has passed through the lower path is mainly discharged from the lower side of the exhaust port 20. Will be.

The operation of the gas water heater 1 having the above structure will be described. When the hot water tap is opened indoors, the control unit 12
Detects this, sends a control command to each part of the apparatus, and burner combustion heating and hot water supply start together with water supply. Heat transfer tube 9
When the water is heated to a desired temperature in, the combustion exhaust after being used for the heating rises and flows into the exhaust hood 8, and a part of the combustion exhaust is guided to the main exhaust passage, Most of the combustion exhaust that is guided to the main exhaust flow path is
After being guided to the rear once, it is guided to the front and discharged from the exhaust port 20 to the outside (arrow Z1). On the other hand, the exhaust hood 8
Part of the combustion exhaust gas flowing into the exhaust gas flows into the auxiliary exhaust gas passage through the hole 25, is guided forward through the auxiliary exhaust gas passage, and is exhausted to the outside through the exhaust port 20 (arrow Z2).

When the thermal efficiency of the gas water heater 1 was measured,
A good value of 82% was obtained. Since the combustion exhaust gas is allowed to escape to the outside through the hole 25, the size (especially height) of the exhaust hood 8 can be made smaller than that of the conventional one.

Although a preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. is there. That is, the shape and the number of the holes 25 are not limited to those in the above embodiment, and the holes 2
If No. 5 is not provided, there is no limitation as long as it is located at a position almost directly above the site where the combustion exhaust gas is not efficiently heat-exchanged. Therefore, when a plurality of holes are formed, the opening method and size may be different for each hole.

[0024]

The exhaust hood of the combustor according to the first aspect of the present invention is designed so that the combustion gas generated from the burner is made to flow substantially evenly over the entire surface of the heat exchange fins and exhausted. There is an effect that the thermal efficiency can be improved.

According to a second aspect of the present invention, the exhaust hood of the combustor has a sub-exhaust flow passage for leaking a part of the combustion exhaust from the front side portion of the straightening plate for guiding the combustion exhaust to the rear and sending it to the exhaust port. Since it is provided, the contact between the combustion gas and the fin surface is good even in the lower part of the front side of the current plate, so that there is an effect that the size can be reduced.

[Brief description of drawings]

FIG. 1 schematically shows an internal structure of a gas water heater according to an embodiment of the present invention, in which (a) is a front view,
(B) is a side view.

2 is an external perspective view of an exhaust hood of the gas water heater shown in FIG.

FIG. 3 is a side view showing a structure of an exhaust hood of the gas water heater shown in FIG.

FIG. 4 is a front view showing a structure of an exhaust hood of the gas water heater shown in FIG.

5 is a top view showing a structure of an exhaust hood of the gas water heater shown in FIG. 1. FIG.

6 (a) and 6 (b) are side views showing the internal structure of a conventional exhaust hood of a gas water heater.

[Explanation of symbols]

8 Exhaust hood 18 Connection frame part 19 Top plate (19a back part, 19b bent part, 19c
Front side part 20 Exhaust port 21 Exhaust top 22 Straightening plate (22a rising part, 22b bent part, 22
c horizontal part) 23 side wall 24 central guide 25 hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsutomu Honma             Paloma work, 6-23, Taoyuan-cho, Mizuho-ku, Nagoya             Business F-term (reference) 3L037 AA02 AC11 AC18

Claims (2)

[Claims] 1. An exhaust hood which is provided above a fin-tube heat exchanger heated by combustion gas of a burner and discharges combustion exhaust gas after heat exchange, and which rises after passing through the heat exchanger. Combustion exhaust gas is guided backwards and then forwards to escape from the exhaust port to the outside, while some combustion exhausts are sent to the exhaust port from the front and escaped to the outdoors without being guided backwards. As a result, the exhaust hood of the combustor is characterized in that the combustion gas generated from the burner is made to flow substantially evenly over the entire surface of the heat exchange fins and exhausted. 2. A main exhaust passage that guides the combustion exhaust gas after heat exchange to the rear by a flow straightening plate and then folds back in a U shape to send the exhaust gas to the exhaust port, and a flow straightener that guides the combustion exhaust gas to the rear. The exhaust hood of the combustor according to claim 1, further comprising: an auxiliary exhaust flow path that leaks a part of the combustion exhaust from the front side portion of the plate and sends it to the exhaust port.