JPS6243095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustor in which a heat exchange chamber is continuously attached to a combustion chamber.

[Conventional technology]

Conventionally, in the case where the exhaust stack is directly connected to the combustion chamber and does not use a heat exchange chamber or other part with large flow resistance, the pressure in the combustion chamber immediately escapes to the exhaust stack, resulting in a very small pressure rise. In those equipped with a heat exchange chamber, it was difficult for the pressure in the combustion chamber to escape to the exhaust stack.

When a pressure spray burner is attached to the burner installation port of the combustion chamber and the atomized fuel is directly ignited by the spark of the ignition electrode, the pressure in the combustion chamber rises rapidly because the fuel is combusted at a constant combustion rate immediately after ignition. .
For this reason, a configuration has been adopted in which air is sent into the combustion chamber by a combustion blower before ignition, forming an air flow from the combustion chamber to the exhaust stack via a heat exchange chamber, making it easier for exhaust gas to escape before ignition. Ta. In addition to countermeasures using such a burner operation system, an electromagnetic pump is used for the fuel pressurization pump, and AC voltage is applied during ignition to spray and ignite the fuel while the pressure of the fuel pressurization pump is low, resulting in a low combustion amount. There is a configuration in which after operating for 2 to 3 seconds, a half-wave rectified voltage is applied to operate at an appropriate pressure.

[Problem that the invention seeks to solve]

By the way, if the structure is such that the pressure in the combustion chamber does not easily escape to the exhaust pipe, the pressure in the combustion chamber will increase rapidly at the time of ignition, and combustion will start with a very loud bang, or the pressure in the combustion chamber will increase. When air cannot be supplied by the blower, the fire suffocates and extinguishes, and when the pressure in the combustion chamber drops, it ignites again and makes an abnormal sound, producing a large amount of black smoke.

As a countermeasure to this problem, rotating the combustion blower for a long time prior to fuel supply and ignition operations increases the time required for the burner to actually start operating after receiving an ignition signal, such as a temperature signal, and the combustion speed increases. This was very inconvenient for those who control temperature by intermittent operation.

In addition, in burners that use a fuel pressurization pump and spray nozzle, the diameter of the atomized fuel particles becomes larger as the ambient temperature and combustion pressure decrease, and a certain fuel pressure is required to ignite. . Even if ignition can be achieved reliably at low pressure at room temperature, if the ambient temperature drops, ignition will not be possible at this low pressure.When switching between AC voltage and half-wave rectified voltage, the pressure characteristics will be a in Figure 4b. If the curve is such that when ignition fails under AC voltage, it will eventually ignite only when the pressure increases after 2 to 3 seconds, and the atomized fuel sent to the combustion chamber by this flame for 2 to 3 seconds will be ignited at once. As the fuel ignited and burned, the pressure in the combustion chamber rose rapidly, producing a loud thud. Also, for a purpose different from this invention, an orifice and a pressure damper were attached to the bypass line connecting the pipe line to the spray nozzle and the suction side of the fuel pressurizing pump, but the pressure characteristics at this time are shown in Figure 4. As in the case of switching between AC voltage and half-wave rectified voltage as shown in curve c of b, a large amount of fuel was sent to the combustion chamber before ignition, and could not be used to improve the ignition sound.

[Means for solving problems]

This invention improves the above problems by obtaining optimal pressure characteristics for a combustor that has a heat exchanger connected to the combustion chamber. Heat exchange room 3 is heat exchange room 2
This is the exhaust stack installed on the 4 is a burner attachment port provided in the combustion chamber, and a pressure spray burner is attached to the burner attachment port 4.

5 is a fuel pressurizing pump for the pressure spray burner, 6 is a spray nozzle, 9 is an ignition electrode whose tip is located in front of the spray nozzle 6, 10 is an igniter that supplies high voltage to the ignition electrode 9, and 13 is a combustion air supply. It is a fan and constitutes a pressure spray burner.

5' is the discharge side of the fuel pressure pump 5 connected to the spray nozzle 6, 5'' is the suction side of the fuel pressure pump 5 connected to the fuel tank (not shown), and the discharge side is connected to the fuel pressure pump 5 by the branch pipe 12. Connect 5° and suction side 5″. 8 is a pressure damper attached to the branch pipe 12; 7 is a pressure detector attached to the branch pipe 12 between the discharge side 5' of the fuel pressurizing pump 5 and the pressure damper 8; The minimum pressure at which the burner can be ignited is detected and the circuit is opened. Also pressure detector 7
may be a pressure valve that opens when a constant force is applied by the force of a spring, and is composed of a switch 7' that detects a constant pressure and a solenoid valve 11, and the solenoid valve 11 opens when a constant pressure is detected. You can also use it as

[Explanation of action]

Since the present invention has the above-described configuration, when a spark is sent to the ignition electrode 9 during ignition operation and the fuel pressurizing pump 5 is activated, the pressure applied to the spray nozzle 6 suddenly rises to the set pressure of the pressure detector 7. This pressure was set as the minimum pressure that could ignite, so under normal conditions, ignition would occur before this pressure was reached. and pressure detector 7
After activation, the pressure damper 8 moves the piston against the built-in spring to increase the storage capacity, so the pressure applied to the spray nozzle 6 decreases the rate of increase in pressure by the amount that is released to the pressure damper 8, reducing the amount of fuel supplied to the combustion chamber 1. The flow rate also increases gradually. For this reason, the amount of combustion gas gradually increases, and the pressure characteristics change to a in Figure 4 a.
It became like a curve and the combustion chamber 1 pressure no longer suddenly increased. At this time, pressure damper 8
When the movement distance of the piston is short and the operation of the pressure damper 8 stops midway, the pressure characteristics will be as shown in curve b in Figure 4a, but in this case it is particularly problematic because time has passed since ignition. There isn't.

Furthermore, in the configuration of the present invention, instead of maintaining the pressure applied to the spray nozzle 8 at the time of ignition for a certain period of time,
Since the pressure is gradually increased by the pressure damper 8, even if the ambient temperature is low and ignition is not possible at the set pressure immediately after the ignition operation, the subsequent pressure increase will immediately adjust the conditions such as the particle size of the atomized fuel. transitions to a state where it can ignite, the actual ignition delay becomes very small, and the amount of fuel sent to the combustion chamber by the time of ignition is also small.

[Explanation of effects]

As described above, in the present invention, in a combustor in which a heat exchanger is installed in the combustion chamber to make it difficult for exhaust gas to escape, the pressure characteristics applied to the spray nozzle due to the action of the pressure detector and pressure damper are as shown in Figure 4a. The result was an a-curve, and the pressure in the combustion chamber rose rapidly after ignition, preventing abnormal temperatures during ignition.

In addition, even if ignition cannot be achieved with the pressure up to the time the pressure damper starts operating, the pressure characteristic is that it gradually increases, so as the pressure rises after the start of operation, the ignition pressure is immediately reached, so a large amount of fuel remains unignited in the combustion chamber. In addition to preventing abnormal noise at the time of ignition, the configuration of this invention has significantly improved ignition performance, making it possible to achieve quieter ignition at a wide range of ambient temperatures. This is an extremely practical invention that can be easily implemented without using any equipment.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the water heater equipped with this invention. FIGS. 2 and 3 are cross-sectional views showing embodiments of this invention. FIG. 4 is a spray pressure characteristic diagram. 1...Combustion chamber, 2...Heat exchange chamber, 3...Exhaust pipe, 4...Burner installation port, 5...Fuel pressure pump, 5'...Pump discharge side, 5''...Pump suction side, 6... spray nozzle, 7... pressure detector,
7'...Detection switch, 8...Pressure damper, 1
1... Solenoid valve, 12... Branch pipe.

Claims (1)

[Claims] 1. A heat exchange chamber 2 is provided continuous with the combustion chamber 1, an exhaust pipe 3 is attached to the heat exchange chamber 2, a burner attachment port 4 is provided in the combustion chamber 1, and a pressure In addition to installing the spray burner, a branch pipe 12 is provided that connects the discharge side 5' and the suction side 5'' of the fuel pressurizing pump 5 of the pressure spray burner, and a pressure damper 8 is installed in the branch pipe 12.
A heat exchanger characterized in that a pressure detector 7 which opens when a constant pressure is detected is attached to a branch pipe 12 between the discharge side 5' of the fuel pressurizing pump 5 and the pressure damper 8 in the combustor equipped with the combustor. Combustor with chamber. 2. The combustor with a heat exchange chamber according to claim 1, wherein the pressure detector 7 comprises a switch 7' which is switched when a constant pressure is detected, and a solenoid valve 11 which is operated by the switch 7'. 3. The combustor with a heat exchange chamber as set forth in claim 1, wherein the pressure detected by the pressure detector 7 is the lowest pressure at which ignition is possible.