JPS6229830A - Liquid fuel combustion device - Google Patents

Abstract

PURPOSE:To improve ignition performance and to stabilize combustion commencing at a time right after ignition, by a method wherein the preheating time of an evaporator is shortened and the temperature of gas during ignition is also always kept at a specific optimum value. CONSTITUTION:Liquid fuel is fed to an evaporator 3 incorporating an electric heater 7 with the aid of a feed oil pump 2 for evaporation, and fuel-air mixture produced through injection of evaporation gas through a nozzle 9 is guided to a burner 10 for combustion. In the device, a timer means generates a pump- driving instruction signal after a given time lapsed after making of a power source, and a pump-driving means drives the feed oil pump 2 for a specified time by means of the instruction signal. Further, a combustion-starting means instructs the starting of combustion by means of a signal from a temperature- detecting means 8 detecting the temperature of the evaporator is shortened and a gas temperature prevailing during ignition is also always kept at a specified optimum value, and ignition performance can be improved and combustion commencing at a time right after ignition can be stabilized.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a combustion device for liquid fuel used for heating, etc., in which liquid fuel (hereinafter referred to as fuel oil) is gasified in a vaporization device equipped with an electric heater. This invention relates to an oil combustor that injects oil from a nozzle into a burner mixing pipe and ignites it.

[Prior Art] Fig. 1 is a schematic configuration diagram showing a combustion apparatus according to the present invention. The fuel in the oil tank (1) is sent to the carburetor (3) by the oil pump (2). The vaporizer chambers 3) each have a vaporizing chamber (6) surrounded by a concentric annular cylindrical outer tube (4) and an inner tube (5).
) and is heated by nine cylindrical heaters (7). The temperature of the carburetor (3) is detected by a temperature sensor (8) attached to the outer tube (4), and the control circuit adjusts the input power to the heater (7) in response to the amount of fuel fed. Temperature is controlled. The fuel is vaporized in the vaporization chamber (6) and sent from the nozzle (9) to the burner (10).
The primary air is ejected into the mixing tube (11), mixed with the sucked primary air, and then combusted in the crater (12). (13)
is a spark plug that generates a high-voltage spark discharge. In addition,
(14) is a needle valve.

During combustion, the solenoid (15) draws air to the right in the drawing to open the nozzle (9), and the solenoid (l5)
The escape valve (16) provided at the rear of the nozzle (9) is closed, but at other times the nozzle (9) is closed and the relief valve (16)
is opened so that the fuel in the vaporization chamber (6) can return to the oil tank (1). In addition, after 9 ignition, the vaporization chamber (6
) to maintain the temperature of the fuel flowing into the tank at the optimum vaporization temperature.
The heater (7) is repeatedly turned on and off.

As described above, the liquid fuel is heated and vaporized in the vaporizer (3), and is ejected from the nozzle (9) provided in the vaporizer (3) to form a mixed gas with air, which is then sent to the burner (10). The combustion device that performs combustion is equipped with a temperature sensor (8) that detects the vaporizer temperature and a combustion start command device that commands the start of combustion based on the signal from the temperature sensor (8). After the power is turned on to the heater (7), when the temperature of the temperature sensor (8) rises to a certain temperature, high pressure discharge, pump drive, and energization of the solenoid are performed to start combustion. Common.

At the time of ignition, when the power is turned on to the heater (7), the heat emitted from the heater (7) is transferred from the internal v (5) to the vaporization chamber (6).
)→outer tube (4)→temperature sensor (8).

A portion of the fuel that was in the vaporization chamber (6) during the previous combustion has already been returned to the oil tank (1) through the relief valve (16) due to combustion stoppage, but some of it has already been returned to the vaporization chamber (6) due to preheating. As the temperature inside increases, the remaining fuel gradually vaporizes. Therefore, there is no liquid fuel in the vaporization chamber (6) (especially in the upper half), and of the above heat transfers, the transfer from the inner tube (5) to the outer tube (4) takes the longest time. It will be necessary,
This caused the preheating time to be long. On the other hand, when the temperature of the temperature sensor (8) reaches the ignition temperature and the command to start combustion is given, the center of the carburetor (3) is already in an overheated state, so fuel is not pumped here. If the vaporized gas is vaporized, the temperature of the vaporized gas will rise too much, the force of the gas ejected from the nozzle (9) will be strong, and excessive air will be sucked in at the burner (10) nozzle (12), resulting in excessive air combustion, so-called lifting. Problems occur, such as combustion occurring or the flame rod (17), which is supposed to be exposed to the flame to detect the flame, failing to detect the flame, causing the safety circuit to automatically stop the operation of the equipment.

If you attempt to prevent this by starting the ignition operation before the temperature sensor (8) has reached the specified ignition temperature, it will be necessary to determine how much kerosene from the previous combustion remains in the vaporizer. Because the gas temperature is not constant, the temperature rise varies and it is difficult to obtain a constant gas temperature.In addition, due to the influence of individual product variations during mass production, aging, etc.2. This was not an effective method for obtaining temperature.

[Problems to be Solved] Under the above-mentioned circumstances, 2. The present invention shortens the preheating time of the carburetor and at the same time maintains the gas temperature at a constant optimum temperature at the time of ignition. 2. Improving ignition performance. 9. Improving flammability immediately after ignition. The aim is to achieve stabilization.

[Means for solving the problem] In order to achieve the above object, the combustion device according to the present invention has the following features:
A device that uses an oil pump to feed liquid fuel into a vaporizer built into an electric heater, vaporizes it, and then blows the vaporized gas out of a nozzle to lead the mixed gas with air to a burner and burn it. , a timer means for generating a pump drive command signal after a predetermined time has elapsed after the power is turned on;
A pump drive means for driving the oil feed pump for a certain period of time in response to the command signal, a temperature detection means for detecting the temperature of the carburetor, and a combustion start command means for commanding the start of combustion based on the signal from the temperature detection means. It is preparation.

[Example] Examples of the present invention are shown in Fig. 1, Fig. 2, and Fig. 3. Fig. 2 shows various devices (means) during preheating when using the vaporizer heating means proposed in the present invention. This is a time chart showing the operation of the heater ().When the power switch is turned on, the heater (
7) is energized to increase the temperature of the vaporizer (3). At the same time, a timer device starts to accumulate time and sends a signal to the pump drive device when a predetermined amount of time has elapsed. The pump drive device thereby drives the oil feed pump (2) for a certain period of time and then stops it. The time specified by the timer device (section A in Figure 2) is such that when the combustion device and the vaporizer start preheating from normal temperature (room temperature), the temperature detection device, that is, the temperature sensor (8), is activated at least within this time. The temperature is set so that the combustion start command device does not issue a command to start combustion due to the temperature reaching the ignition temperature.

While the timer device is working (section A), the temperature inside the vaporization chamber (6) gradually increases, and some of the vaporization chamber (6) during the previous combustion
The fuel remaining in the tank is vaporized and returned to the oil tank (1) through the leakage valve (16). Therefore, almost no fuel in the vaporization chamber (6) exists in a liquid state.

Next, in section B in which the pump drive device operates the oil feed pump (2) during preheating, the fuel that has entered the vaporization chamber (6) mainly receives heat from the inner pipe (5) of the vaporizer (3). Temperature of the outer tube (4) of the vaporizer (3) and the temperature sensor (8) attached to the outer tube (4) in order to absorb and raise the temperature and move inside the vaporization chamber (6) while partially gasifying. rises rapidly. The third figure shows how the temperature of the temperature sensor (8) increases over time. It can be seen that by driving the oil feed pump (2), the temperature of the temperature sensor (8) increases faster and the total time until it reaches the ignition temperature is shortened.

If the fuel pump (2) continues to be driven even after the vaporization chamber (6) is filled with fuel oil and vaporized gas.

Since it returns to the oil tank (1) through the relief valve (16) while removing heat from the vaporization chamber (6), the vaporizer (
3) The temperature will decrease. For this reason, the period B during which the oil pump (2) continues to drive during preheating is sufficient to fill the vaporization chamber (6) with fuel and vaporized gas.

Although it is affected to some extent by the room temperature when preheating starts, the timing at which the temperature of the temperature sensor (8) reaches the ignition temperature is almost at the same time as or after the end of the oil feed pump (2) drive during preheating. The cumulative time of the timer device (section A) and the drive time of the oil feed pump (2) (section B) are set so that the operation is performed at a relatively early timing. Unnecessarily prolonging the time until ignition after the pump drive device stops will increase the temperature of the vaporized kerosene gas in the vaporization chamber (6), reducing the effectiveness of the present invention.
Because it is a thing, it must be avoided.

Effects of the Invention As explained above, the liquid fuel combustion device according to the present invention has both a means for driving an oil feed pump for a certain period of time after a predetermined period of time has elapsed after the start of preheating, and a means for detecting the vaporizer temperature. By operating the oil pump during preheating to allow kerosene to flow into the vaporizer and facilitate heat transfer to the temperature sensor, the waiting time until ignition can be shortened. Since the temperature of the gas is relatively uniform, the temperature of the gas ejected from the nozzle at the time of ignition does not temporarily become excessively high, resulting in good ignition performance and stability of the combustion state after ignition. Furthermore, since heat transfer from the heater to the temperature sensor is good, aging of the vaporizer and dimensional variations in vaporizer devices have little effect on preheating time.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of the liquid fuel combustion device according to the present invention, Figure 2 is a time chart showing the operation of each device during preheating, and Figure 3 is a graph showing the temperature of the temperature sensor of the vaporizer during preheating. It is. 3... vaporizer, 6... vaporization chamber, 7...
····heater. 8...Temperature sensor. Patent applicant Representative of Dainichi Industries Co., Ltd.
Fumio Sasaki 1' 1st Flash Figure 2

Claims (1)

[Claims] A device that uses an oil pump to feed liquid fuel into a vaporizer built into an electric heater, vaporizes it, and then blows the vaporized gas out of a nozzle to lead the mixed gas with air to a burner and burn it. , timer means for generating a pump drive command signal after a predetermined period of time has elapsed after the power is turned on;
A pump drive means for driving the oil feed pump for a certain period of time in response to the command signal, a temperature detection means for detecting the temperature of the carburetor, and a combustion start command means for commanding the start of combustion based on the signal from the temperature detection means. A combustion device characterized by comprising: