JPS62202928A - Combustion air control unit - Google Patents

Abstract

PURPOSE:To control combustion air so as to prevent the combustion from stopping caused by a sudden wind and condensed water and further a poor combustion from occurring by providing in the control unit an air control plate, and a bypass port opened in a primary air chamber for introducing a minimum and necessary volume of air thereinto. CONSTITUTION:At the time of a maximum combustion, air sent by a combustion fan 4 affords a dynamic pressure Pd(kg) to an air control plate 12 which is a leaf spring loaded in a primary air opening 11 opened in a primary air chamber 10. Then, the air control plate 12 is opened against the pressure of the spring and sends primary air to the primary air chamber 10. Upon this occasion, assuming that the spring constant be (k) and the distance between openings be X(mm), X equals Pd/k. When the spring constant (k) of the air control plate 12 and the opening degree of the primary air opening 11 and a bypass port 13 are selected suitably, combustion is not stopped by the sudden wind and condensed water even at a TDR point, and it becomes possible to prevent poor combustion such as lifting, back-fire or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a combustion device for supplying hot water or space heating by burning fuel such as gaff or petroleum at a high throttling ratio.

BACKGROUND OF THE INVENTION A water heater using a conventional combustion air control device of this type is shown in FIG. In the figure, 1 is a burner and 2 is a nozzle. 3 is a heat exchanger, 4 is a combustion fan that sends combustion air to the burner, 5
is a gas proportional valve, 6 is an air flow rate sensor, 7 is a temperature sensor, and 8 is a control circuit.

The control circuit 8 controls the proportional valve 5 to eliminate the difference between the temperature of hot water supplied from the heat exchanger 3 measured by the temperature sensor 7 and the set temperature. k is set, and the amount of air is measured by the air flow rate sensor 6 and fed back to the control circuit 8 to set it to a predetermined amount of air. In this way, a predetermined amount of gas supplied from the nozzle v2 and a predetermined air fiffi supplied from the combustion fan 4 are used to combust in the burner 1 and heat water in the heat exchanger 3 to supply hot water.

Problems to be Solved by the Invention With the above configuration, when the minimum combustion amount (CTDR point) is set to 1/4 to accommodate hot water supply in the kitchen, the air amount is also set to 1/4 in order to maintain combustion. I need to narrow it down to about 4. However, if the amount of air is less than 1/2, combustion may stop during gusts of wind, or a large amount of dew water will form, making hot water supply impossible.

The present invention solves such conventional problems, and controls combustion air so that even if the TDR point is made small, combustion will not be stopped due to gusts of wind or condensed water, and combustion defects will not occur. The purpose is to

Means for Solving the Problems For the above purpose, the combustion air control device of the present invention comprises: a nozzle for injecting fuel, a burner, a primary air chamber facing a mixing pipe of the burner and containing a nozzle /l/; an air chamber that includes the burner and a primary air chamber; a combustion fan that is joined to the air chamber and sends air to the burner; a primary air port that opens at a position facing the combustion fan in the primary air chamber; and a primary air port. It consists of an air control plate with spring pressure damped in the direction opposite to the air dynamic pressure sent from the combustion fan, and a bypass port opened in addition to the primary air chamber to send in the minimum required air.

At the time of maximum combustion, the air sent by the combustion fan applies dynamic pressure to the air control plate installed in the primary air port opening into the primary air chamber, and the air control plate opens against the spring pressure to control the primary air. Deliver primary air to the room. A mixture is created between the primary air and the fuel ejected from the nozzle, and is combusted in the burner together with secondary air sent through the air chamber by the combustion fan.

On the other hand, at the TDR point, the dynamic pressure of the air sent to the combustion fan decreases, the spring pressure prevails, the air control plate closes, and primary air is supplied from the bipanu L which opens into the primary air chamber.

At this time, the air control plate and the bypass port are appropriately set so that the primary air ratio (PA) at maximum combustion and at the TDR point is almost the same, and the amount of air is about 1/2 at the TDR point.

Example Embodiments of the present invention will be described below with reference to all accompanying drawings.

1 and 2 show an embodiment of the present invention (f) when applied to a water heater), in which the same members as in FIG. 4 are given the same reference numerals. 9 is an air chamber, 10 is a primary air chamber, 11 is a primary air port, 12 is an air control plate, 13 is a bypass port, and 14 is a burner mixing pipe.

The nozzle/1/2 connected to the proportional valve 5 is the mixing pipe 1 of the burner 1.
4, the nozzle/I/2 is included in the primary air chamber 10, and the burner 1 and the primary air chamber 1o are included in the air chamber 9. The combustion fan 4 is joined to the air chamber 9 and is located opposite a primary air port 11 that opens into a primary air chamber 10. At the primary air port 11, there is an air control plate 12 whose spring pressure is damped in a direction opposite to the air dynamic pressure sent from the combustion fan 4.
As shown in FIG. 2, the primary air chamber 10 is provided with a bypass port 13 for feeding the minimum required air. A heat exchanger 3 is provided downstream of the burner 1, and a temperature sensor 7 is installed at the outlet of the heat exchanger 3.

During maximum combustion, the air sent by the combustion fan 4 applies a dynamic pressure Pd (kg)' to the air control plate 12, which is a leaf spring, installed in the primary air port 11 opened in the primary air chamber 10. The air control plate 12 opens against the pressure and sends primary air to the primary air chamber 10. At this time, the spring constant is k (kg/mm
), and the aperture distance X=-. Although a plate spring is used for the air control plate 12 here, the same effect can be obtained by combining a plate and a spring. Next, at the TDR point, the desired hot water temperature and temperature sensor 7
The proportional valve 5 reduces the combustion rate to 1/4 so as to eliminate the difference between the detected temperature and the detected temperature.
At the same time, the control circuit 8 controls the combustion engine 4 to reduce the amount of air to about 1/2. Air volume is 1/
2, the dynamic pressure Pd' applied to the air control plate 12 is 1A, and the opening distance of the air control plate 12 is X'=1/4.
becomes. Therefore, it is possible to make the ratio of primary air to total air extremely smaller at the TDR point than at the time of maximum combustion.

The relationship between total air and primary air will be explained with reference to FIG. The excess air ratio m, which represents the total air, is set to 1.6 at maximum combustion and 3.2, which is 1/2 the amount of air at the TDR point, so that combustion does not stop due to gusts or condensation.

If there is no air control device of the present invention, the PA indicated by a dashed line
It changes from 509[+ to 10096 like this.

When PA becomes 100, for example, 13A gas causes combustion lift, and 6C gas causes backlash.

Due to the spring constant of the air control plate 12 of the present invention, the primary air port 1
1 and the bypass port 13, the PA will only change from 50 inches to 60 inches, as shown by the broken line in FIG. In this way, in fact, in the five water heaters, combustion does not stop due to gusts of wind or condensed water even at the TDR point, and it is possible to prevent combustion defects such as lift and back. becomes.

Effects of the Invention As described above, the combustion air control device of the present invention provides the following effects.

(1) The air excess ratio m is used to control the opening distance of the primary air using the air dynamic pressure sent from the combustion fan and the air control board.
Even if the primary air ratio (P
A) can be kept constant.

(2) Since the primary air ratio (PA) is constant, stable combustion can be maintained without lift or backing occurring at the maximum combustion time or at the TDR point.

(3) Since the PA is constant, there is no need to limit the amount of air, and combustion will not be stopped due to gusts of wind or condensed water.

(Since there are 4 bypass ports, even if the air control board is damaged, the minimum required amount of air is ensured and combustion defects will not occur.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a water heater employing a combustion air control device according to an embodiment of the present invention, Fig. 2 is a perspective view of the same essential parts, and Fig. 3 shows combustion amount, excess air ratio m, and primary air ratio. A characteristic diagram showing the relationship with PA, FIG. 4 is a configuration diagram of a conventional water heater. 1...Burner, 2...Nozzle, 4...
...Combustion fan, 9...Air chamber, 10...
...Primary air chamber, 11...Primary air port, 1
2...Air control board, 13...Bypass port, 14...Mixing pipe. Name of agent: Patent attorney Toshio Nakao and 1 other person7-
--Bar 1? --- Nozzle 4 --・Tsuba 50% --) Tnwo --- Air detection l θ --- Shiku Kutakukan / / --- 11 Water air port / 2 --- Ichiku Qla version / J --- Bypass U 14-h Brass Figure 1 Figure 2 Figure 3 In 7'y) (KcatlI) Figure 4

Claims (1)

[Claims] A nozzle and a burner that eject fuel, a primary air chamber that faces the mixing pipe of the burner and includes the nozzle, an air chamber that includes the burner and the primary air chamber, and a combustion fan that is joined to the air chamber and sends air to the burner. a primary air port opening at a position facing the combustion fan of the primary air chamber; and an air control plate installed in the primary air port and having a spring pressure braked in a direction opposite to the air dynamic pressure sent from the combustion fan. , a combustion air control device consisting of a bypass port that is open in addition to the primary air chamber and sends in the minimum required air.