JPS5818055Y2 - Forced supply and exhaust gas combustor - Google Patents

Description

[Detailed explanation of the invention] This invention relates to a forced exhaust gas combustor, which uses an exhaust fan installed in an exhaust stack connected to the top of the device body to exhaust combustion waste gas and exhaust air during combustion in the main burner. If a thermal switch that opens at a preset safe temperature or higher and closes the gas safety valve is attached to the thermal switch mounting part that has a ventilation hole located at an appropriate position on the surrounding wall on the suction side of the fan, and an exhaust failure occurs. The present invention is applied to a forced air supply/exhaust type gas combustor equipped with a safety device that detects exhaust gas swell with the thermal switch, closes the gas safety valve, and cuts off the gas supply.

Conventionally, in this type of gas combustor, after the main burner is extinguished, the exhaust fan stops and the heat exchanger etc. retains a large amount of heat.The residual heat causes the exhaust stack to rise to a high temperature, and the thermal switch is activated as a safety device. The problem was that the gas safety valve would close when activated.

Although this drawback can be overcome by increasing the sensing temperature of the thermal switch, in this case the amount of waste air released indoors increases accordingly, which is not desirable from a safety standpoint.

This idea was developed in a forced supply/exhaust type gas combustor equipped with the above safety device by allowing the exhaust fan to rotate as needed even after the main burner has been extinguished, thereby eliminating the need for the safety device when the device is used under normal exhaust conditions. This corrects the drawbacks of the conventional system by making it inoperable.

An embodiment in which this invention is applied to a water heater will be described below based on the drawings.

In the drawings, reference numeral 1 denotes an exhaust fan installed in a fan case 8 attached to the upper part of the exhaust pipe 2, and is rotated by a motor M.

Further, the exhaust pipe 2 is connected to the water heater main body 3 with a baffle 4 interposed therebetween.

Reference numeral 6 denotes a thermal switch mounting part which is provided at an appropriate position on the peripheral wall of the exhaust fan 1 in the exhaust pipe 2 on the suction side and has a large number of ventilation holes 5. Install a thermal switch that detects and operates the safe temperature.

In FIGS. 1, 3, and 4, Sl indicates a gas safety valve 1 which is attracted and held open by an electromagnet 11 magnetized by the thermoelectromotive force of a thermocouple 10 heated by a pilot burner 9.
A well-known normally closed thermal switch (
The first thermal switch (hereinafter referred to as a first thermal switch) has a contact that opens by the action of a bimetal or the like at a temperature higher than a preset safe temperature.

That is, leakage of combustion exhaust gas from the vent hole 5 into the installation chamber is accurately detected and the gas safety valve 12 is closed at a safe temperature.

S2 is a normally open type second thermal switch having a contact that closes at a temperature higher than a set temperature lower than the safe temperature, and the second thermal switch S2 is installed below the first thermal switch S1 in the thermal switch mounting part. If there is a large temperature rise after the hot water supply stops, that is, after the main burner 13 disappears, this temperature is sensed and the exhaust fan 1 is rotated at the set temperature. Second thermal switch S,, S
, to eliminate the drawback that the first thermal switch S1 is activated after a one-time stop.

Further, the second thermal switch S2 is connected in parallel with a limit switch S3 that is activated during combustion in the main burner 13 to control the exhaust fan 1.

In the embodiment shown in FIG. 1, the exhaust fan 1 is controlled by gas pressure detection, and when the main gas valve 23, which is opened and closed by the pressure of flowing water, opens, the gas presses the diaphragm of the gas pressure switch 24. The structure is such that the contact of the limit switch S3 is turned on, and the contact of the transformer relay 22 is also turned on at the same time, causing the exhaust fan 1 to rotate.

Here, instead of the gas pressure sensing type, a water pressure sensing type may be used.

In the figure, reference numeral 14 denotes an exhaust extension pipe connected to the fan case 8, which passes through the wall 15 and is guided outside, and has an exhaust top (
(not shown).

16 is a fin-and-tube type heat exchanger, 17 is a gas introduction pipe, 18 is a water supply pipe, 19 is a hot water outlet pipe, and 20 is a water governor.

Since this invention is configured as described above, the main burner 13 burns during tapping, the contacts of the limit switch S3 and the transformer relay 22 close, the motor M of the exhaust fan 1 rotates, and the first... The flow of air supply and exhaust is shown by arrow a in FIG.

In addition, when the exhaust fan 1 stops due to a suspension of hot water tap, the waste air flows through the ventilation hole 5 to the exhaust pipe 2, as shown by the arrow.
radially outward through the gap between the baffler 4 and the water heater main body 3 (see FIGS. 1 and 3). Flow through contact with S2.

Here, if the temperature rise after stopping the hot water tap is large, the second thermal switch S2 detects this in advance of the first thermal switch S1 and rotates the exhaust fan 1, and the first thermal switch S2 immediately rotates the exhaust fan 1. Second
Thermal switch S1. S2 is cooled, the first thermal switch S□ does not operate, and the gas safety valve 12 does not close.

That is, in the gas combustor of this invention, the first. Second thermal switch S1. Since the temperature S2 is suppressed to a temperature slightly higher than the set temperature of the second thermal switch S2, it never becomes a safe temperature.

This eliminates the conventional drawback that the gas supply is cut off after the twin burners are extinguished during normal use unless the safety temperature is raised considerably.

Here, if the exhaust fan 1 becomes unable to exhaust air due to a failure of the motor M, etc., the exhaust air flows indoors as shown by the arrow in the same way as above (exhaust air overflows), and the first thermal switch S1 rises to the set temperature. Since the gas safety valve 12 is activated and the gas safety valve 12 is closed, safety is ensured.

Although FIG. 1 shows an embodiment in which the baffle 4 with the exhaust pipe 2 attached is attached to the water heater main body 3 while maintaining a ventilation gap,
It is also possible to eliminate this ventilation gap by connecting the exhaust pipe 2 to the water heater body 3.
Of course, it is also possible to attach it directly to the.

1st. In Figure 3, 1. 2nd thermal switch S□
, S2 are mounted vertically on the same thermal switch mounting portion 6, but it goes without saying that they may be mounted on separate thermal switch mounting portions at appropriate locations.

According to this invention explained above, when the exhaust fan becomes unable to discharge combustion exhaust gas, the first thermal switch installed on the intake side of the exhaust fan in the exhaust stack detects a temperature rise above the safe temperature and activates. This cuts off the gas supply and prevents leakage of waste gas to ensure safety.After the main burner is extinguished, the residual heat inside the main burner causes the second thermal switch to raise the temperature above the set temperature, which is lower than the safe temperature. When this happens, the system detects this and activates the exhaust fan to rotate and exhaust the air, so the exhaust pipe and exhaust extension pipe are kept at a low temperature, making it ideal for disaster prevention, and making it possible to keep the safe temperature as low as possible, making it impossible to exhaust the air. The leakage of combustion waste gas indoors can be greatly reduced, resulting in significant improvements in safety and ease of use of the appliance.

[Brief explanation of drawings]

The drawings show one embodiment of this invention; Fig. 1 is an overall longitudinal sectional front view, Fig. 2 is a partially cutaway plan view of the exhaust fan, and Fig. 3 is an enlarged view taken along line X-X in Fig. 1. The sectional view and FIG. 4 are electrical circuit diagrams. 1...Exhaust fan, 2...Exhaust pipe, 3
・・・・・・Combustor main body, 4・・・・・・Baffler-5・
...Vent hole, 6...Thermal switch mounting part, Sl...1st thermal switch, S2.
...Second thermal switch.

Claims (1)

[Scope of utility model registration request] An exhaust stack equipped with an exhaust fan is installed on the gas combustor body, and while the main burner is burning, the exhaust fan exhausts the combustion waste air, and a ventilation hole is provided in the peripheral wall of the exhaust stack, which is the suction side of the exhaust fan. A perforated thermal switch mounting part was provided, and a first thermal switch was installed in the thermal switch mounting part to close a gas safety valve that has a contact that opens at a preset safe temperature or higher to prevent exhaust gas from flaring up due to poor exhaust. In the gas combustor, a forced supply/exhaust type gas characterized in that a second thermal switch having a contact point that closes at a temperature higher than a set temperature lower than the safe temperature and rotating an exhaust fan at the contact point is installed in the thermal switch mounting part. combustor.