JPH1089679A - Gas combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a burner cooling effect due to post-purging, to shorten a time up to re-ignition, and to improve handling operability by rotating a burner motor at higher revolution speed than that at the time of igniting for a predetermined time, and inhibiting restart of burning operation during this period. SOLUTION: A hot water supply cock 9 is opened during burning operation, and a water flow stop is sensed by a water flow switch 7. And, gas valves 4, 5 and a proportional valve 6 are closed, and the burning operation is stopped. At this time, a revolution speed of a burner motor 3 is set to higher revolution speed HH than a pre-purging revolution speed so far. Simultaneously, a re- ignition inhibit timer and a post-prepurging timer are set. When the closing operation of the cock 9 during the burning operation is instantaneous and the cock 9 is opened immediately after the closure, water flow check is repeatedly realized until the set timer is counted up. During the period, the motor 3 is rapidly rotated at the predetermined speed HH, and the heated burner 2 is forcibly cooled in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas combustion apparatus for burning a gas to supply hot water or heat.

[0002]

2. Description of the Related Art Conventionally, this type of gas combustion apparatus has a post-purge function of rotating a burner motor for a certain period of time to cool the burner section even when the combustion operation is stopped. In particular, in a combustion device such as a water heater in which a hot water tap is repeatedly closed and opened in a short time, the burner section is heated due to a continuous combustion state due to a delay in a detection operation of a flowing water switch. When a hot-water tap is closed and opened, a re-ignition prohibition time is provided to regulate re-ignition of the burner, so that the burner is cooled to some extent and then re-ignited. This is because if the re-ignition is performed while the burner is overheated, a flashback phenomenon occurs in which the fire burns inside the burner and explosion sounds are generated at the time of ignition, or the durability of the burner is significantly reduced due to overheating. This is because it occurs.

[0003]

However, in the conventional apparatus, during the re-ignition prohibition time, that is, during the post-purge,
Since the burner motor is rotating at the same speed as the number of revolutions (prepurge speed) that can supply the combustion air required for ignition, it takes time to cool down the burner due to insufficient air volume, and it takes too much time before re-ignition. And it was extremely inconvenient.

An object of the present invention is to solve the above-mentioned drawbacks, and to drive the burner motor at a rotation speed higher than the pre-purge rotation speed during the re-ignition prohibition time to improve the cooling effect, thereby increasing the time until re-ignition after stopping the combustion. It is an object of the present invention to provide a safe and easy-to-use gas combustor, which has a reduced length.

[0005]

That is, according to the present invention, in a gas combustion apparatus which performs a post-purge operation for cooling a burner by rotating a burner motor for a predetermined time after stopping the combustion operation, the burner motor is operated for a predetermined time when the combustion is stopped. The engine is rotated at a predetermined rotation speed higher than the rotation speed at the time of ignition, and the restart of the combustion operation is prohibited during this time.

[0006]

FIG. 1 is a system configuration diagram schematically showing a gas water heater to which the present invention is applied.

First, the configuration of a gas water heater will be described with reference to FIG. 1. Reference numeral 1 denotes a heat exchanger, and an internal burner unit 2 has gas valves 4 and 5 for gas supply and gas supply amounts. A gas pipe 13 provided with a gas proportional valve 6 for adjusting the pressure is provided, and a burner motor 3 for supplying combustion air to the burner section 2 is mounted below the gas pipe 13. Further, the water inlet side of the heat exchanger 1 is connected to a water pipe via a water supply line 11, and a flowing water switch 7 for detecting a water supply amount in the middle thereof.
Are arranged. On the other hand, the outlet side of the heat exchanger 1 is provided on the hot water supply line 1 on which a hot water supply sensor 8 for detecting the temperature of hot water is disposed.
2 is connected, and a hot water tap 9 is attached to a tip end thereof. An igniter 10 generates a discharge spark for ignition.

Although not shown, a remote control panel having a temperature setting switch, an operation switch, and the like is connected to the gas water heater, and is installed in a kitchen or the like to start or stop the equipment, or The setting of the hot water supply temperature and the like can be remotely controlled.

The above is the schematic configuration of the gas water heater. Next, the operation of the apparatus will be described based on the operation flowchart of FIG. 2 and the operation timing chart of FIG.

[0010] When the operation switch is operated, the equipment is started, and when the user opens the hot water tap 9, water flows in from the water supply pipe 11, the water flow is detected by the water flow switch 7, and the burner unit 2 is turned on. It is ignited and the water heater starts burning operation.
The water flowing through the water supply pipe 11 undergoes heat exchange in the heat exchanger 1 and is supplied from the hot water tap 9.

The details of the above-described ignition operation for the burner unit 2 will be described with reference to the operation timing chart of FIG.
First, the burner motor 3 is driven by opening the hot water tap 9 (step 21). When the burner motor 3 reaches a rotation speed capable of supplying combustion air necessary for igniting the burner unit 2 (that is, a prepurge rotation speed L), the gas valves 4 and 5 and the igniter 1
0, the proportional valve 6 is sequentially turned on, and the burner 2 is ignited (step 22). Thereafter, when ignition of the burner unit 2 is confirmed by a flame detector (not shown), the igniter 10 is turned off, and the igniter 10 is turned off according to the temperature difference between the set temperature of the temperature setting switch and the detected temperature of the hot water supply sensor 8. Thus, the combustion speed is controlled such that the number of revolutions of the burner motor 3 and the opening of the proportional valve 6 are controlled to maintain the hot water at the set temperature (step 23).

When the hot water tap 9 is closed during the combustion operation, the stop of the water flow is detected by the water flow switch 7, and the gas valves 4, 5 and the proportional valve 6 are all turned off to stop the combustion operation.
At this time, the revolving speed of the burner motor 3 is set to a higher revolving speed HH than the pre-purge revolving speed L, and at the same time, a reignition prohibition timer (for example, setting of 3 to 4 seconds) for prohibiting reignition of the burner unit 2 is performed. Then, a timer for securing the post-purge operation is set (step 24).

If the operation of closing the hot-water tap 9 during the combustion operation is instantaneous and the hot-water tap 9 is opened immediately after the closing, the re-ignition prohibition timer set in step 24 is counted up. Until then, the program repeatedly executes the processing of loop 20, that is, the running water check,
In the meantime, the burner motor 3 rotates at a high speed at a predetermined rotation speed HH and forcibly cools the heated burner unit 2 in a short time.
When the reignition prohibition timer expires, the rotation speed of the burner motor 3 is shifted to the original prepurge frequency L (step 2).
1) When the pre-purge rotation speed L drops, the gas valve 4
5, the proportional valve 6, and the igniter 10 are turned on to perform an ignition operation in the same manner as described above (step 22). After the burner unit 2 is ignited, reburn control is performed based on the hot water supply sensor 8 (step 2).
4).

As described above, when the ignition of the burner unit 2 is extinguished by the instantaneous plugging / unplugging operation of the hot water tap 9, the burner motor 3 is rotated at a rotation speed HH higher than the prepurge rotation speed L.
It is a feature of the present invention that the burner unit 2 is forcibly cooled by rotating the burner unit for a predetermined time to realize a faster reburning operation than in the past. By such control, a safe and easy-to-use gas water heater is provided. Becomes possible.

If the hot-water tap 9 is kept closed, steps 25 and 26 are sequentially executed, and the burner motor 3 rotates at a high speed until the re-ignition prohibition timer expires. Up to pre-purge rotation speed L
(Step 27). During this time, hot water tap 9
If the opening operation is not performed, the burner motor 3 stops (step 28).

[0016]

As described above, according to the present invention, when the combustion is stopped, the burner motor is rotated for a predetermined time at a predetermined rotation speed higher than the rotation speed at the time of ignition, and during this time, the reburn operation is prohibited. As a result, the effect of cooling the burner section by the post-purge is improved, the time until re-ignition is shortened, and the usability is improved.

In particular, even in the case of a combustion apparatus such as a gas water heater in which a hot water tap is repeatedly opened and closed in a short time, the combustion is performed after the burner is cooled down in a short time and reliably. Since the operation is restarted, the problems such as the flashback phenomenon at the time of re-ignition, the explosion sound or the decrease in the durability of the burner due to overheating as in the related art are eliminated, and the safety is further improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a gas water heater to which the present invention is applied.

FIG. 2 is a diagram showing the operation timing of the gas combustor of the present invention.

FIG. 3 is an operation flowchart of the gas combustor.

[Explanation of symbols]

 2 Burner section 3 Burner motor

Claims (1)

[Claims] 1. A gas combustion apparatus which performs a post-purge operation for cooling a burner by rotating a burner motor for a certain time after stopping a combustion operation, wherein the burner motor is rotated for a certain time at a predetermined time higher than the rotation speed at the time of ignition when the combustion is stopped. A gas combustion device which rotates at a rotation speed and prohibits restarting of the combustion operation during this time.