JP2767971B2 - Combustor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a combustor used for a heater or the like.

2. Description of the Related Art Generally, a combustor of this type needs to heat a vaporizing section 1 to an appropriate temperature in order to vaporize a liquid fuel as shown in FIG. Therefore, at the time of ignition, the vaporizer 1 is preheated to a predetermined temperature by energizing the heater 2 embedded in the vaporizer 1. When the temperature of the vaporizing section 1 reaches a predetermined temperature, fuel is injected into the vaporizing section 1 from the fuel supply nozzle 4 by a pump or the like. The fuel injected into the vaporizing section 1 is vaporized here, premixed with primary air for combustion sent into the vaporizing section 1 by a blower or the like, sent to the burner 3, ignited by an appropriate ignition means, and burned. To start. And when burning,
The temperature of the vaporizing section 1 is maintained by receiving heat from the burner section 3, and when sufficient heat cannot be obtained, the heater 2 is energized to maintain the temperature of the vaporizing section.

Problems to be Solved by the Invention However, it was very difficult to keep the temperature of the vaporizing section 1 constant in the above-mentioned combustor. In other words, the combustion state of the combustor changes from strong to weak, but when it is strong, the heat received from the burner section 3 is large, and when it is weak, the heat received is small. It was very difficult to keep the temperature of the vaporizing section 1 constant by receiving heat from the burner section 3. Particularly, in the case where the combustion air is supplied to the burner section 3 through the periphery of the vaporizing section, when the combustion air is taken in from outside, the temperature of the combustion air is greatly different between nighttime and daytime. There has been a problem that the temperature of the vaporizing section 1 is not constant, so that the electricity supply rate to the heater 2 is increased, the electricity cost is increased, and the combustion becomes unstable. Further, when the fire is extinguished, the temperature of the vaporizing section 1 is high, so that the nozzle 4 that has stopped supplying fuel has a higher temperature than during combustion due to the heat of the vaporizing section 1, and the fuel that has accumulated inside the nozzle 4 As a result, there was also a problem that the temperature became high and tar was formed, and the nozzle was clogged.

The present invention has been made to solve such a problem, and enables to keep the temperature of the vaporizing section almost constant without increasing the duty ratio to the heater, and to cool the vaporizing section in a short time at the time of fire extinguishing. It is intended to prevent tarring of fuel in the nozzle.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention sets a large amount of heat received by a vaporization unit that receives the heat of combustion of a burner unit, and further comprises a temperature detection unit provided in the vaporization unit. In addition to adjusting the degree of cooling of the vaporizing section based on the output from the controller, the temperature of the vaporizing section is maintained at a substantially constant level, and vaporizing section cooling means for maximizing the degree of cooling of the vaporizing section during fire extinguishing is provided.

According to the present invention, the vaporizing section is maintained at a substantially constant temperature regardless of the combustion state and the outside air temperature by cooling by the cooling means by the above configuration, and the power supply to the heater is reduced and the combustion becomes stable. In addition, the cooling time of the vaporizing section at the time of fire extinguishing is shortened, and the tarring of fuel in the nozzle can be prevented.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to an example in which a vaporization unit is cooled using secondary air for combustion.

In FIG. 1, reference numeral 11 denotes a bottomed cylindrical vaporizing / mixing cylinder (hereinafter, referred to as a vaporizing section). A fuel supply nozzle 12 and a primary combustion air supply pipe 13 are located at an eccentric position of a part of the peripheral wall. There is not. 14 is a heater buried in the vaporizing section 11, and 15 is a vaporizing section.
A burner portion covering the upper opening of 11 has a vertically elongated flame port 15a provided on a peripheral wall thereof. Reference numeral 16 denotes a burner cap covering the upper opening of the burner section 15, 17 a burner ring disposed around the burner section 15, 18 a burner case surrounding the vaporization section 11, and 19 a burner case 18. A cooling-side secondary air supply pipe for supplying combustion-use secondary air into the inside, a secondary air guide A 20 for guiding the secondary air to the outer periphery of the burner portion, a heating-side secondary air supply pipe 21 and a secondary air guide pipe 22 Guide the next air to the outer periphery of the burner 2
The secondary air guides B and 23 are secondary air supply pipes, and 24 is a damper for arbitrarily distributing the secondary air to the heating side and the cooling side, and is driven by a stepping motor or the like. Reference numeral 25 denotes a temperature detecting unit embedded in the vaporizing unit 11, and 26 denotes this temperature detecting unit.
A control unit that drives the damper 24 based on the output from the control unit 25 and keeps the temperature of the vaporizing unit almost constant. The control unit mainly includes a microcomputer for combustion control incorporating a sequence as shown in the flowchart of FIG. is there. The vaporizing section 11 is provided with a burner section by considering the configuration of the peripheral portion of the opening.
It is set so that the amount of heat received from 15 can be taken more than the conventional one.

In the above configuration, the fuel injected into the vaporizing section 11 by the pump or the like at the start of combustion is vaporized in the vaporizing section 11 which is heated to a high temperature by the heater 14, and is sent into the vaporizing section 11 by a blower or the like. Premix with primary air for combustion. The premixed gas flows into the burner section 15 while rotating in the vaporizing section 11, and is ejected from a flame port 15a on the side wall of the burner section. Then, when ignited by appropriate ignition means, combustion starts,
A flame is formed that closely adheres to 15a. Here, at the time of this ignition, the control unit 26 causes the secondary air to flow only to the heating side by the damper 24 based on the output from the temperature detection unit 25 because the temperature of the vaporization unit is low. The state is maintained until the target temperature is increased by receiving heat. After reaching the target temperature, based on the output from the temperature detection unit 25, the damper 24 and open or close in one of the directions,
The amount of secondary air flowing to the cooling side 19 is adjusted. That is, if the temperature of the vaporizing section 11 is high, a large amount of secondary air flows to the cooling side 19 to increase the degree of cooling by the step indicated by 27 in FIG. The degree of cooling is reduced by rotating the damper.

Next, at the time of fire extinguishing, the fuel supply from the nozzle 12 is stopped, and at the same time, the control
Drives the damper 24 to fully open the cooling-side secondary air supply pipe 19 for a predetermined time so that the secondary air flows only to the cooling-side secondary air supply pipe 19. Therefore, the vaporizing section 11 is cooled rapidly, and the temperature of the nozzle 12 is maintained at a temperature lower than the temperature at which fuel is tarified in the nozzle.

As described above, in this embodiment, the temperature of the vaporizing section can be maintained at a substantially constant temperature only by receiving heat from the burner during combustion, without relying on energization of the heater 14. And strong ~
A large margin can be provided for various fluctuation factors such as a weak change in the combustion state, a change in the combustion air temperature, and a variation in the accuracy of the parts. In addition, since the vaporizing section 11 can always be maintained near the target temperature, the durability is improved. In addition, when the fire is extinguished, the degree of cooling of the vaporizing section is maximized, so that the cooling time of the vaporizing section can be shortened and, at the same time, tarring of the fuel in the nozzle can be prevented. Further, in this embodiment, since the combustion air is used for controlling the temperature of the vaporizing section, it is not necessary to provide a separate air supply source for supplying the cooling air for the vaporizing section, which is advantageous in terms of cost.

Although the secondary air for combustion is used to cool the temperature of the vaporizing section 11 in the above embodiment, it may be simply air or water for cooling, as long as it cools the vaporizing section 11. Of course, it may be something like this.

Effect of the Invention As is clear from the description of the embodiment, according to the present invention, by controlling the cooling of the vaporizing section, the temperature of the vaporizing section can be easily maintained at a target value, and the energization rate to the heater can be reduced. At the same time, the combustion becomes stable. In addition, it is possible to increase the margin for various fluctuation factors, and furthermore, it is possible to always maintain the temperature of the vaporizing section at a substantially constant temperature. Furthermore, by cooling the vaporization section in a short time at the time of fire extinguishing, the temperature of the fuel supply nozzle facing the vaporization section can be prevented from rising, and the fuel does not tar in the nozzle and the nozzle is not clogged. The durability is also improved, the reliability during long-term use is high, and the electricity cost is low and the device is easy to use.

[Brief description of the drawings]

FIG. 1 is a sectional view of a combustor according to an embodiment of the present invention, FIG. 2 is a flowchart of the control unit, and FIG. 3 is a sectional view showing a conventional combustor. 11 …… Vaporization section, 15 …… Burner section, 18 …… Burner case,
19, 24, 26 ... cooling means, 19 ... cooling side secondary air supply pipe,
24 damper, 25 temperature detector, 26 controller.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23N 5/02 342 F23D 11/44

Claims (1)

(57) [Claims] A burner for burning a mixed gas of fuel gas and primary air; a vaporizer for receiving the heat of combustion of the burner to vaporize liquid fuel and supply the fuel gas to the burner; A temperature detecting unit that detects the temperature of the vaporizing unit, and adjusting the degree of cooling of the vaporizing unit based on the output from the temperature detecting unit to maintain the temperature of the vaporizing unit almost constant and maximize the degree of cooling of the vaporizing unit during fire extinguishing. A combustor provided with an evaporator cooling means.