JP2951464B2 - Safety device for combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device used in a combustion apparatus such as a water heater for detecting a shortage of air supply and exhaust.

[0002]

2. Description of the Related Art In a combustion apparatus in which combustion air is sucked by a fan and burns at a predetermined air-fuel ratio, an air-supply filter is blocked by dust, oil, or the like, and the predetermined air-fuel ratio cannot be maintained. The amount may be insufficient. Ma
And, to be there also cause exhaust defective clogged fins of generated heat exchanger. Therefore, conventionally, a safety device for stopping the operation of the combustion equipment when such a defective air supply / exhaust is detected is incorporated. This defective supply / exhaust is detected using a wind pressure switch or the like that is turned on and off according to the pressure difference between the combustion chamber and the fan case. Recently, a two-stage system has been known in which a warning is output without stopping the combustion when the supply / exhaust level is low, and the combustion is stopped when the supply / exhaust level is high. I have.

[0003]

However, in the conventional apparatus, in order to catch such a supply / exhaust failure at two levels, a total of two sets of wind pressure switches having different operation levels of the contacts have to be provided. For this reason, the installation space for the wind pressure switch, the pressure guide tube, and the like must be widened, and it has been difficult to meet the recent demand for compactness. Also, the number of parts and the number of manufacturing steps increase, which leads to an increase in cost. An object of the present invention is to provide a safety device for a combustion apparatus, which solves the above-mentioned problem while maintaining a desired safe operation by using only one differential pressure sensor such as a wind pressure switch.

[0004]

According to the present invention, there is provided a safety device for a combustion apparatus for detecting a shortage of supply and exhaust of a combustion apparatus which burns by inhaling combustion air with a fan. Differential pressure detection means for detecting a pressure difference between the combustion chamber and the fan case or a pressure difference between the combustion chamber and the equipment case; a rotation number switching means for switching the rotation number of the fan to a plurality of stages during post-purge; When the predetermined pressure difference is not detected by the differential pressure detecting means when the rotation speed is high, the combustion stop mode is set. When the rotation speed is high, the predetermined pressure difference is detected. When the pressure difference is small, the abnormal mode discriminating means sets a warning mode when the predetermined pressure difference is not detected. In the combustion stop mode, combustion of the combustion equipment is prohibited. And gist further comprising an abnormality processing means for informing the abnormality without prohibited.

[0005]

According to the safety device for a combustion apparatus of the present invention having the above-described structure, the number of rotations of the fan is switched to a plurality of stages during post-purging by the rotation number switching means, and the pressure difference between when the number of rotations is large and when the number of rotations is small is reduced. (Pressure difference between the combustion chamber and the fan case or the equipment case) is detected by the differential pressure detecting means. If the predetermined pressure difference is not detected when the fan rotation speed is high, combustion of the combustion device is prohibited.If the predetermined pressure difference is detected when the fan rotation speed is high, but the rotation speed is low, If the predetermined pressure difference is not detected,
Notify abnormalities without prohibiting combustion. Generally, the pressure difference increases as the number of rotations of the fan increases, but if the supply / exhaust failure occurs, the pressure difference decreases as the degree of the supply / exhaust failure increases. Therefore, if the predetermined pressure difference cannot be obtained when the fan rotation speed is high, it is determined that the level is a dangerous supply / exhaust defective level, and combustion is prohibited, and the predetermined pressure difference cannot be obtained only when the fan rotation speed is low. In such a case, the abnormality is notified without prohibiting the combustion as a low level supply / exhaust defect.
As a result, two levels of detection can be performed by one differential pressure detecting means, so that downsizing, reduction in the number of parts, and the like can be achieved. In addition, by reporting abnormalities at low level,
There is no malfunction that suddenly stops the combustion equipment,
Very convenient.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of a safety device for a combustion apparatus according to the present invention will be described below. FIG. 1 is a schematic configuration diagram in which a safety device as one embodiment is applied to a water heater. The water heater 1 includes a combustion chamber 3 provided in the center of the appliance case 2, and a heat exchanger 5 that exchanges heat with water passed through a heat transfer tube (not shown) by combustion heat generated by a burner 4 in the combustion chamber 3. An exhaust hood 6 provided at an upper portion of the heat exchanger 5 and an exhaust pipe 7 for discharging combustion exhaust, and a fan 8 (at the bottom of the combustion chamber 3 for sucking combustion air and supplying the combustion air to the combustion chamber 3 ( In this embodiment, a sirocco fan) is provided. The combustion air is
The combustion chamber 3 is taken in from an air supply port 9 provided on the side of the appliance case 2 by the rotation of the fan 8, and dust is removed by an air supply filter 10 and then passed through a fan case 11.
Sent to

[0007] Fuel gas is supplied to the burner 4 by a gas conduit 12. The gas conduit 12 has a main solenoid valve 13 that only opens and closes a gas flow path, and a proportional solenoid valve 1 that is set to an opening in accordance with a control signal and adjusts to a desired gas supply amount.
4 are provided in series. Then, a motor (not shown) of the fan 8 is controlled (rotational speed control) so that an amount of combustion air corresponding to the gas supply amount is supplied to the combustion chamber 3.

In order to detect a shortage of supply and exhaust in the supply and exhaust system described above, a wind pressure switch 20 for detecting a difference between the pressure in the fan case 11 and the pressure in the combustion chamber 3 is provided. The wind pressure switch 20 includes a pressure guiding tube 21 communicating with the inside of the fan case 11 in the first chamber 22 of the diaphragm, and a pressure guiding tube 23 communicating with the inside of the combustion chamber 3 in the second chamber 2 of the diaphragm.
4, and the contact portion 25 is turned on when the pressure difference between them is equal to or higher than a predetermined pressure.

A controller 30 for controlling the combustion system and the supply / exhaust system is provided in the appliance case 2.
The controller 30 includes a CPU, a RAM, and a ROM that constitute a well-known arithmetic logic operation circuit (not shown), an input interface that inputs signals from various sensors, an output interface that outputs drive signals to various actuators, and the like. Microcomputer. In FIG. 2, the dashed line indicates the input / output relationship of only the configuration related to the supply / exhaust shortage detection process which is a feature of the present invention.
The controller 30 includes a remote controller 31 for remote operation.
Is connected. The remote controller 31 includes a normal temperature setting switch, an operation switch, and the like (not shown), and a warning lamp 32 (a warning buzzer may be used) for notifying a supply / exhaust failure.
Is provided. Note that a similar warning lamp 33 is provided on the water heater main body side.

Next, a description will be given of a supply / exhaust shortage detection process executed by the controller 30. This process is performed during post-purge after the end of combustion. In the post-purge period, as shown in FIG.
The rotation is performed at 0 rpm / min for a predetermined period (hereinafter, this period is referred to as a first period).
The motor is rotated at a speed of 000 rpm / min for a predetermined period (hereinafter, this period is referred to as a second period). Thereafter, the fan 8 is rotated at, for example, 1500 rpm / min for normal post-purging.

Then, the state (on or off) of the wind pressure switch 20 in each of the first and second periods is read, and as shown in Table 1, both the first and second periods (only in the first period). If the wind pressure switch 20 is on, the normal mode is set, and if the wind pressure switch 20 is off in the first period, but is turned on in the second period, a low-level air supply / exhaust condition is determined to be low. If it is off in both the first and second periods (or only the second period), it is determined that the supply / exhaust deficiency is at a high level, and the stop mode is set.

[Table 1]

When the warning mode is set, the warning lamps 32 and 33 blink to notify the user of the abnormality.
On the other hand, when the stop mode is set, subsequent combustion is prohibited to prevent danger due to incomplete combustion or the like. For this reason, when the air supply filter 10 is clogged due to long-term use and the air supply / exhaust is defective, the abnormality is first notified by the warning lamps 32 and 33, so that the air supply filter is stopped before the appliance stops. It is possible to return to normal by cleaning 10 etc., and it is very easy to use without trouble because hot water cannot be supplied suddenly.

Further, since the abnormality is detected in accordance with the pressure difference between the first and second periods in which the number of rotations of the fan is different, one wind pressure switch 20 can be used to detect abnormality at two levels of combustion inhibition and warning. Can be detected. As a result, there is no need to provide two sets of wind pressure switches as in the related art, and the water heater 1 can be made compact, and the number of manufacturing steps, the number of parts, and the like can be reduced. Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. For example, in the present embodiment, the pressure difference between the inside of the combustion chamber 3 and the inside of the fan case 11 is used. Can be.

[0014]

As described above, the safety device for a combustion apparatus according to the present invention switches the number of rotations of the fan to a plurality of stages during post-purge to reduce the differential pressure between when the rotation speed is high and when the rotation speed is low. Since detection is performed, a single wind pressure switch can detect abnormality at two levels, that is, combustion inhibition and warning. As a result, it is not necessary to provide two sets of wind pressure switches as in the related art, and it is possible to reduce the size of the combustion equipment and the number of manufacturing steps and parts. In addition, by notifying the abnormality at the time of the low level, there is no problem that the combustion is suddenly stopped, and the usability is very good.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a water heater as one embodiment.

FIG. 2 is a graph showing the number of rotations of a fan during post-purge.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water heater, 2 ... Appliance case, 3 ... Combustion chamber, 8 ... Fan, 11 ... Fan case, 20 ... Wind pressure switch, 30 ...
Controller, 32, 33 ... warning lamp.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-149029 (JP, A) JP-A-5-118532 (JP, A) JP-A-61-285316 (JP, A) 41949 (JP, U) Shokai Sho 57-120850 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23N 5/18 101 F23N 5/24 104 F23N 5/26 101

Claims (1)

(57) [Claims] A safety device for detecting insufficiency of supply and exhaust of combustion equipment that inhales and burns combustion air with a fan, wherein a pressure difference between a combustion chamber and a fan case or a pressure difference between a combustion chamber and an equipment case is detected. A differential pressure detecting means for detecting, a rotational speed switching means for switching the rotational speed of the fan to a plurality of stages during post-purging, and a predetermined rotational speed predetermined by the differential pressure detecting device when the rotational speed is high among the switched rotational speeds. When the pressure difference is not detected, the combustion stop mode is set. When the rotation speed is high, the predetermined pressure difference is detected. When the rotation speed is low, the warning mode is set when the predetermined pressure difference is not detected. Means and abnormality processing means for prohibiting combustion of the combustion equipment in the combustion stop mode and notifying the abnormality without prohibiting combustion in the warning mode. Safety device for combustion equipment.