JPH071087B2 - Combustion device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a combustion device such as an FF warm air heater, a hot water boiler, and the like.

2. Description of the Related Art Generally, as shown in FIG. 4, a combustion device of this type has an air supply fan 33 driven by a motor 32 and a mixing plate 34 in a burner case 31, and burns naturalized gas that has been naturalized in a vaporization section 35. Burn at mouth 36. At this time, the combustion primary air is supplied from the air supply fan 33 to the inside of the vaporization unit 35, and the combustion secondary air is also supplied from the outside of the vaporization unit 35 by the air supply fan 33 to the secondary air holes of the vaporization unit 35. It is adapted to be supplied to the central portion of the flame mouth portion 36 via 37.

Problems to be Solved by the Invention However, this type of combustion device has a heat exchanger.
When used in equipment such as FF warm air heaters and hot water boilers, equipment that can switch between strong and weak combustion or change the combustion amount is designed to save energy and effectively use energy by designing high heat exchange efficiency of the equipment. Dew condensation of combustion gas occurs in the heat exchanger or the exhaust pipe during weak combustion. Therefore, there is a problem that the thermal efficiency at the time of strong combustion cannot be set high, or the variable range of the combustion amount of strong to weak cannot be made large. Also, in cold regions, condensed water may freeze in the exhaust pipe,
When this condensation occurs, there is a problem that exhaust gas enters the room and causes a serious accident.

The present invention solves such a conventional problem, and is intended to prevent dew condensation in the heat exchanger or the exhaust pipe during weak combustion.

Means for Solving the Problems In order to solve the above problems, the combustion apparatus of the present invention includes a burner case having a combustion section, an exhaust pipe or a heat exchanger provided on the downstream side of the burner case, and A main blower for supplying primary air for combustion to the combustion section, a sub blower provided separately from the main blower for supplying secondary air to the combustion section, a rotation speed control device for the sub blower, and the exhaust pipe Alternatively, a temperature sensor or a condensation sensor provided in the heat exchanger is provided, and when the sensor detects a predetermined temperature or a condensation state, the rotation speed control device adjusts the amount of air from the auxiliary blower to increase. .

Action The present invention, while maintaining a good combustion state by the above configuration,
The secondary air, which does not significantly affect the combustion performance, is adjusted to an appropriate value to prevent dew condensation by a sensor installed in a part of the heat exchanger or in the exhaust pipe. That is, during strong combustion, the amount of secondary air is minimized to minimize the excess air ratio and obtain high thermal efficiency. On the other hand, as the temperature shifts to weak combustion and the temperature of the exhaust pipe immediately before reaching the dew condensation temperature or immediately before dew condensation, the amount of secondary air is increased and the excess air ratio is gradually increased to lower the heat exchange efficiency and reduce the exhaust pipe temperature. To prevent condensation within the exhaust pipe.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a burner case, which has a combustion section 1a composed of a vaporization section 2 and a flame mouth section 3, a mixing plate 4 provided inside the vaporization section 2, and a motor 6 for driving a sub blower 5. is doing. A main blower 8 is connected to the side surface of the burner case 1 via a duct 7. 9 is an ignition electrode, 10
Is a frame rod. FIG. 2 is an example in which the combustion apparatus of the present invention is used in a hot water boiler, and the heat exchanger 12 provided in the main body 11 is connected to the downstream side of the burner case 1. A temperature or condensation sensor 13 is installed in the exhaust passage of the heat exchanger 18.
The temperature of the auxiliary blower 5 is changed by the temperature or the condensation sensor 13. Therefore, 14 is a rotation control device that performs tap angle switching or phase angle control by SCR, 15
Is a rotation control device of the main blower 8, 16 is a hot water outlet, and 16b is a hot water inlet.

In the above configuration, the primary air supplied from the main blower 8 in the vaporization unit 2 is agitated by the mixing plate 4 with the fuel supplied from the fuel pump (not shown) through the oil supply pipe 17, and the flame nozzle It is ejected from the portion 3 and ignited and burned by the ignition electrode 9. On the other hand, the auxiliary blower 5 is coaxial with the mixing plate 4 and is rotated by the motor 6, and intakes air from the secondary air supply port 19 and the vaporizing cylinder fixing plate 21.
It is jetted to the central portion 3a of the flame nozzle 3 through the hole 21a on the outer periphery of the nozzle and the hole 2a provided on the outer periphery of the vaporizing portion 2 and is supplied as secondary air.

When the combustion mode shifts to weak combustion, the rotation speed of the main blower 8 is adjusted according to the discharge amount of the fuel pump (not shown) to control the primary air amount to an appropriate level, but the auxiliary blower 5 and the mixing plate 4 are used.
The motor 6 that drives the temperature or condensation sensor 13
It is changed to an appropriate value by. That is, in the case of weak combustion, the heat exchange becomes too good and the exhaust gas temperature decreases, so
When the temperature attached to the exhaust side of the vehicle or the dew condensation sensor 13 is near the dew condensation limit temperature, the sensor 13 detects this and increases the rotation speed of the motor 6 through the rotation control device 14 to increase the secondary air amount. Let As a result, the excess air ratio increases, so that the amount of exhaust gas increases, the heat exchange efficiency decreases, and the exhaust pipe temperature rises.

Next, another embodiment of the present invention will be described with reference to FIG. In FIG. 3, the point different from the above embodiment is that a part of the primary air supplied through the duct 7 is sucked through the hole 18a of the partition plate 18 and is supplied as secondary air by the auxiliary blower 5. That is the point. According to this configuration, the air supply system is unified into one, which is advantageous in the configuration in the case of a closed combustion device such as an FF warm air heater. Further, since the secondary air supply port 19 and related parts are eliminated, there is an advantage that the structure can be simplified.

Further, if a small-diameter air hole 20a is provided in a part of the shelter 20, the air supplied from the sub-blower 5 will be in the central portion of the flame mouth portion 3.
In addition to being supplied as secondary air from 3a, the air holes 20a
As a result, it can be supplied as tertiary air. As a result, the excess air ratio during weak combustion can be set to a higher value with almost no effect on the combustion state, which is effective in preventing dew condensation in the exhaust pipe.

EFFECTS OF THE INVENTION As described above, according to the combustion apparatus of the present invention, even in a combustion apparatus designed with high efficiency, when dew condensation starts to occur during “weak” combustion, the amount of secondary air is increased to raise the exhaust temperature. Therefore, dew condensation can be prevented. Particularly, in the present invention, the excess air ratio is increased during weak combustion, so the dew condensation temperature of the exhaust gas is lowered, and this synergistic effect can prevent dew condensation more reliably. Therefore, it is possible to expand the variable range (TDR) of strong to weak combustion amount, which enables comfortable heating, energy saving, and reduction of the on / off frequency of equipment.

[Brief description of drawings]

FIG. 1 is a sectional view of a combustion apparatus according to an embodiment of the present invention,
FIG. 2 is a cross-sectional view when the same combustion device is used in a hot water boiler, and FIG. 3 is a cross-sectional view of the combustion device in another embodiment,
FIG. 4 is a sectional view of a conventional combustion device. 1 ... Burner case, 1a ... Combustion section, 5 ... Sub-blower,
8 ... Main blower, 12 ... Heat exchanger, 13 ... Sensor.

Claims (1)

[Claims] 1. A burner case having a combustion section, and an exhaust pipe or a heat exchanger provided on the downstream side of the burner case,
A main blower for supplying primary air for combustion to the combustion section, an auxiliary blower provided separately from the main blower for supplying secondary air to the combustion section, a rotation speed control device for the auxiliary blower, and the exhaust gas. It is equipped with a temperature sensor or a condensation sensor provided in a pipe or a heat exchanger, and when the above-mentioned sensor detects a predetermined temperature or a condensation state, the rotation speed control device adjusts so as to increase the amount of air from the auxiliary blower. Combustion device.