JP2000028137A - Vaporization control device of vaporizing type combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vaporization control device that enables a satisfactory ignition and combustion regardless of the temperature of liquid fuel at a starting time of an operation and the amount of residual liquid fuel inside a vaporizer. SOLUTION: In a vaporization control device of a vaporizing type combustion apparatus comprising a vaporizer for vaporizing liquid fuel, an heater 2 for heating the vaporizer, and a temperature-detecting means 16 detecting the temperature of the vaporizer, the device is provided with a time-measuring means measuring a time period in which the temperature detected by the temperature- detecting means 16 reaches a first predetermined temperature since energization of the heater 2 is started. The minimum time that is required until the vaporizer accumulates a quantity of heat by which a combustion operation is possible is predetermined as a reference preheating time. The device is provided with a judging means that halts energization of the reater 2 when the time period measured by the time-measuring means is shorter than the reference preheating time, then, that starts the combustion operation when the temperature of the vaporizer reaches a second predetermined temperature, and that energizes the heater 2 again when it does not reach the second predetermined temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vaporization control apparatus for a vaporization type combustor for vaporizing and burning liquid fuel.

[0002]

2. Description of the Related Art An evaporative combustor of this type will be described with reference to FIGS. Reference numeral 2 denotes a cylindrical heating element, and an inner tube 3 is disposed in a hollow portion of the heating element 2 to form a first-stage vaporization chamber 4. Inner tube 3
The shallow groove is finely formed on the inner wall surface for the purpose of expanding the heat transfer area. The shallow groove may be of any shape as long as it can greatly increase the heat transfer area (for example, 1.5 times or more), but the depth of the groove is 0.5 mm or less, preferably about 0.2 mm, and It is formed spirally or linearly in the axial direction of the vaporizing chamber 4.

[0005] Reference numeral 5 denotes a second-stage vaporization chamber, in which a middle tube 6 and an outer tube 7 are arranged concentrically outside the heating element 2. The upstream side of the rear-stage vaporization chamber 5 is turned back and communicates with the front-side vaporization chamber 4 and has a vent 8 on the downstream side. A jet pipe 10 having a nozzle 9 at the tip is connected to the vent 8, and the nozzle 9 is configured to open when the solenoid body 11 sucks the valve rod 12. Reference numeral 13 denotes a heat transfer cylinder having a shape as shown in FIG. A plurality of small passages 14 are formed. In addition, 15 is a filler, 18 is a tank, 19 is an oil feed pump,
Reference numeral 20 denotes one side upstream of the inner pipe 3, and the other side is an oil feed pipe communicating with the oil feed pump 19, and 17 is a burner.

[0004] In the above-described structure, when the heating element 2 is energized, heat from the heating element 2 is transmitted to the inner pipe 3 and the middle pipe 6, so that the temperatures of the first and second vaporization chambers 4 and 5 rise. . After a lapse of a certain time, when the vaporizer temperature detected by the temperature detecting means 16 reaches a predetermined temperature, the oil feed pump 19 is driven, and the kerosene in the tank 18 flows into the preceding vaporization chamber 4 through the oil feed pipe 20. The kerosene that has flowed into the pre-evaporation chamber 4 flows down while increasing the temperature, and evaporates on the way to become a vaporized gas. This vaporized gas enters the ejection pipe 10 from the second-stage vaporization chamber 5 via the vent 8, is ejected from the nozzle 9 to the burner 17, and ignites and burns.

[Problems to be solved by the invention]

[0005] In the conventional vaporizer, the amount of vaporized gas ejected, that is, the amount of combustion can be varied by controlling the amount of liquid fuel delivered from the oil pump 19. 4 (a) and 4 (b) show the vaporized state of the liquid fuel inside the vaporizer 1, where the black arrows indicate the flow of the liquid fuel and the white arrows indicate the flow of the gasified liquid fuel. Is shown. The heat transfer cylinder 13 is omitted for the sake of explanation. (A) is when the delivery amount of the liquid fuel is the maximum, and since the liquid fuel contacts the heat transfer cylinder 13 widely and increases the heat absorption amount, the boundary oil level rises. On the other hand, (b) shows a state in which the amount of liquid fuel sent out is the minimum, and the liquid fuel heated during the passage through the pre-evaporation chamber 4 comes into contact with the heat transfer cylinder 13 heated to a high temperature, thereby quickly. Since the gas is sequentially vaporized, the boundary oil level between the liquid fuel and the vaporized gas is kept low. Thus, the boundary oil level between the liquid fuel and the vaporized gas rises and falls according to the amount of combustion.

Therefore, when the combustion is stopped, the amount of liquid fuel remaining in the carburetor 1 also changes, which affects the heat transfer state inside the carburetor 1 when restarting the operation, and the temperature detection means 16 Even if the detected vaporizer temperature reaches the predetermined temperature,
In some cases, normal ignition and combustion operations could not be performed.

FIGS. 10 and 11 show vaporizer temperature and heating element control operations in the conventional control. FIG. 10 shows a case where the combustion operation is started in a state where almost no liquid fuel remains in the carburetor 1. When the power supply to the heating element 2 is started by the operation start operation, the heat from the heating element 2 is reduced. At the same time as being transmitted from the middle tube 6 to the outer tube 7 via the heat transfer tube 13 to the outer tube 7, the vaporized gas of the liquid fuel slightly remaining in the vaporizer is used as a heat medium.
The temperature of the temperature detecting means 16 provided on the ejection pipe 10 is raised. In this case, since the heat transfer coefficient of the vaporized gas as the heat medium is low, the time required for the vaporizer temperature to reach the predetermined temperature at which the combustion operation can be started becomes longer, but the amount of heat accumulated in the vaporizer 1 reaches the predetermined temperature. Therefore, a sufficient amount of heat to start the combustion operation can be secured. Therefore, there is no undershoot in which the temperature of the vaporizer decreases after ignition, and the liquid fuel is completely vaporized and good combustion is performed.

On the other hand, FIG. 11 shows a case where a large amount of liquid fuel remains in the vaporizer 1, but since the liquid fuel having a much higher heat transfer coefficient than the vaporized gas becomes the heat medium, the heating element 2 The heat transfer from the first to the temperature detecting means 16 is accelerated, and the temperature detecting means 16 detects the predetermined temperature in a shorter time than usual. However, the amount of heat accumulated in the carburetor 1 decreases in proportion to the time required to reach the predetermined temperature, and is insufficient for starting the combustion operation. Therefore, if liquid fuel is supplied to the carburetor 1 at the start of the combustion operation, the amount of heat of the carburetor 1 required to vaporize the liquid fuel is significantly short.
The undershoot of the carburetor temperature after the start of combustion becomes very large, so that the combustion cannot be continued and the fire may be extinguished.

Therefore, the present invention addresses such a situation,
An object of the present invention is to provide a vaporization control device of a vaporization type combustor capable of performing good ignition and combustion regardless of the amount of liquid fuel remaining in the vaporizer at the start of operation.

[0010]

According to the present invention, there is provided a vaporizer for vaporizing a liquid fuel, a heating element for heating the vaporizer, and a temperature detecting means for detecting a vaporizer temperature. A vaporization control device for a vaporization-type combustor for supplying liquid fuel to the vaporizer to vaporize and burn the fuel, wherein a temperature detected by the temperature detection means reaches a first predetermined temperature after energization of the heating element is started. Time-measuring means for measuring the time until, and the minimum time required until the carburetor accumulates the amount of heat that can start the combustion operation is set as a reference preheating time, and the time measured by the timekeeping means is equal to or less than the reference preheating time. In the case of, energization of the heating element is stopped for a predetermined time, and thereafter,
When the vaporizer temperature has reached a second predetermined temperature, a combustion operation is started, and when the vaporizer temperature has not reached the second predetermined temperature, determination means for re-energizing the heating element is provided. The present invention relates to a vaporization control device for a vaporizing combustor.

The time for re-energizing the heating element is not less than the remaining time obtained by subtracting the time measured by the timer from the reference preheating time, and the vaporizer temperature falls within the re-energizing time. 2. The vaporization control device for a vaporization type combustor according to claim 1, wherein a combustion operation is started when the temperature reaches a second predetermined temperature.

[0012]

According to this structure, when the time required for the vaporizer temperature to reach the first predetermined temperature is equal to or shorter than the reference preheating time, the power supply to the heating element is temporarily stopped, and after the predetermined time elapses, If the carburetor temperature has reached the second predetermined temperature, it is determined that the carburetor has warmed to some extent and the combustion operation is started, but if the carburetor temperature has not reached the second predetermined temperature, a large amount of It is determined that the temperature detecting means has detected the first predetermined temperature in a short time shorter than the reference preheating time since the liquid fuel has remained, and the heating element is energized for a further predetermined time. Irrespective of the state, good ignition and combustion are always possible.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

1 and 2, the carburetor 1 has a heating element 2 in a middle tube 6 and a nozzle 9 which is opened and closed by a valve rod 12 movable by a solenoid 11 at the tip.
16 is a temperature detecting means for detecting the temperature of the vaporizer 1, and 17 is a burner for burning the vaporized gas. Reference numeral 18 denotes a tank storing liquid fuel, and an oil feed pump 19 is provided on the tank 18. Reference numeral 20 denotes an oil supply pipe that supplies the liquid fuel pumped by the oil supply pump 19 to the vaporizer 1.

FIG. 5 is a diagram showing the configuration of the control unit 21. The time measuring means 22 measures the time from the start of energization to the heating element 2 to the output of a signal indicating that the temperature detecting means 16 has detected a certain temperature. It is supposed to. The judging means 23 determines the heating element 2 based on the outputs of the timekeeping means 22 and the temperature detecting means 16.
It is determined whether it is necessary to stop energizing the power supply and re-energize it, and output a signal to the combustion control means 24. In response to the output signal from the determination means 23, the combustion control means 24 energizes the heating element 2, drives the oil feed pump 19, and further energizes the solenoid body 11.

In the above-described configuration, when an operation start operation is performed by an operation switch (not shown), the combustion control means 24 starts energizing the heating element 2 in response to an instruction from the control unit 21, and the vaporizer 1 is heated. . When the vaporizer temperature detected by the temperature detecting means 16 satisfies a predetermined condition, the oil feed pump 19 is driven, and the liquid fuel is sent to the vaporizer 1 through the oil feed pipe 20 to become a vaporized gas. When the valve rod 12 moves backward, the vaporized gas is ejected from the opened nozzle 9 to the burner 17 and combustion starts at the same time.

Next, the operation of the above configuration will be described with reference to the flowchart of FIG. When an operation switch (not shown) is pressed and an operation start operation is performed, the combustion control unit 24 starts energizing the heating element 2 according to an instruction from the control unit 21 and the vaporizer 1 is heated (step 1). The timing operation is started by the timing means 22 (step 2).

The judging means 23 judges whether the vaporizer temperature detected by the temperature detecting means 16 has reached a first predetermined temperature (step 3), and terminates the timekeeping if it has reached the first predetermined temperature (step 3). Step 4) The measured time is compared with the reference preheating time (Step 5). The reference preheating time is defined as the time required for the carburetor 1 to accumulate a heat amount at which the combustion operation can be started. It is the minimum required time.

Further, when the measured time is equal to or longer than the reference preheating time, the judging means 23 considers that the carburetor 1 has completed the preheating normally and drives the oil feed pump 19 to shift to the start of the combustion operation. If the measured time is less than the reference preheating time, the temperature detecting means 16 is used when the vaporizer 1 is slightly warmed immediately after the fire is extinguished or because a large amount of liquid fuel remains inside the vaporizer 1. Can detect the first predetermined temperature in a short time that is shorter than the reference preheating time. In the latter case, the temperature detecting means 16 detects the first predetermined temperature. However, since the time for actually heating the vaporizer is insufficient, if the combustion operation is started in this state, the vaporizer temperature will be reduced. A large undershoot occurs, leading to poor combustion.

Therefore, when the measured time is less than the reference preheating time, the judging means 23 stops energizing the Td heating element 2 for a predetermined time (step 6), and then sets the vaporizer temperature to the second predetermined temperature. It is determined whether it has reached (step 7). When the vaporizer 1 is slightly warmed immediately after the fire is extinguished, the vaporizer 1 is sufficiently heated by the heating element 2, and after a predetermined time Td due to residual heat, the vaporizer temperature becomes the second temperature. Since the temperature has reached the predetermined temperature, the combustion operation is started.
On the other hand, if a large amount of liquid fuel remains in the vaporizer 1, the heating by the heating element 2 is insufficient, and the vaporizer temperature does not reach the second predetermined temperature even after the elapse of Td. It is determined that it is necessary to perform the re-energization, and the re-energization time T is determined by the combustion control means 24 (step 8), and re-energization to the heating element 2 is started (step 9). Thereafter, the combustion operation is started if the vaporizer temperature reaches the second predetermined temperature (step 10) or if T seconds have elapsed from the start of re-energization (step 11).

Here, the predetermined time Td is a time determined for the purpose of preventing an abrupt temperature rise (overshoot) of the vaporizer temperature due to re-energization of the heating element 2. Is set so that the cumulative energization time from the start of energization for the first time is equal to or longer than the reference preheating time, that is, the sum of the time measured until the vaporizer temperature reaches the first predetermined temperature is equal to or longer than the standard preheating time. Is determined to be However, if the vaporizer temperature is
When the predetermined temperature is reached, the power supply to the heating element 2 is immediately stopped and the combustion operation is started.

FIGS. 7 to 9 are for explaining a specific state of the vaporizer 1 according to the present invention. FIG. 7 shows a case where the temperature detecting means 16 detects the first predetermined temperature in a time shorter than the reference preheating time. FIG. 3 is a time chart showing a vaporizer temperature and a heating element control operation. Here, the reference preheating time is T,
An example in which a predetermined time for stopping the energization of the heating element 2 is set as Td is shown. Note that T and Td are determined by the amount of heat of the vaporizer 1.

FIG. 7 shows a case where the vaporizer 1 is slightly warmed immediately after the fire is extinguished. Since the time A until the vaporizer temperature reaches the first predetermined temperature is shorter than the reference preheating time T, the predetermined time Td The energization of the heating element 2 is stopped. However, since the vaporizer 1 is sufficiently heated, the temperature of the vaporizer after the power supply to the heating element 2 is stopped has reached the second predetermined temperature, and after the power supply to the heating element 2 is stopped, After the elapse of Td, the oil feed pump 21 is driven to start the combustion operation.

FIG. 8 shows a case in which a large amount of liquid fuel remains in the carburetor 1. The time A until the carburetor temperature reaches the first predetermined temperature is shorter than the reference preheating time T, so that the Td heating element is used. Although the energization to 2 has been stopped, the subsequent vaporizer temperature has not reached the second predetermined temperature. Therefore, the heating element 2 is re-energized for the remaining time B1 (B1 = TA), which is obtained by subtracting the time A required until the vaporizer temperature reaches the first predetermined time from the reference preheating time T, and then starts the combustion operation.

In FIG. 9, the re-energization time T is determined and the heating element 2 is re-energized in the same manner as in FIG.
Since the vaporizer temperature has reached the second predetermined temperature at 2 (B2 <B1), the combustion operation starts immediately.

[0026]

As described above, the vaporization control device for a vaporization type combustor according to the present invention sets the reference preheating time as the minimum time required for the vaporizer to accumulate the amount of heat that can start the combustion operation. Comparing the time from when the heating element is energized to when the vaporizer reaches the first predetermined temperature with the reference preheating time, and decides whether to start the combustion operation or re-energize the heating element based on the result. With such a configuration, excellent ignition and combustion can be obtained regardless of the amount of liquid fuel remaining in the vaporizer at the start of the combustion operation, and excellent effects such as improving the durability of the vaporizer can be obtained. Play.

According to the second aspect of the present invention, the re-energizing time of the heating element is determined from a minimum time required for the carburetor to accumulate a heat amount at which the combustion operation can be started, and the re-energizing is further performed. Since the combustion operation is started immediately when the vaporizer temperature reaches the second predetermined temperature within the time, it is possible to obtain better ignition / combustion, and to reduce the time from the start of operation to the ignition. The present invention realizes a very practical vaporization control device for a vaporization type combustor because it is not made longer than necessary.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional example and a vaporizer of the present example.

FIG. 2 is a schematic explanatory view of a vaporizer, an oil feed pump, a tank, and a burner according to a conventional example and this embodiment.

FIG. 3 is a perspective view of a heat transfer cylinder of the vaporizer of the conventional example and the present embodiment.

FIG. 4 is an explanatory diagram of a vaporized state of liquid fuel in the vaporizers of the conventional example and the present embodiment.

FIG. 5 is a block diagram showing a main part of the embodiment.

FIG. 6 is a flowchart illustrating a heating element control method according to the present embodiment.

FIG. 7 is a time chart showing a vaporizer temperature and a heating element control operation when the vaporizer is slightly warmed in the embodiment.

FIG. 8 is a time chart showing a vaporizer temperature and a heating element control operation when a large amount of liquid fuel remains in the vaporizer in this embodiment.

FIG. 9 is a time chart showing a vaporizer temperature and a heating element control operation when a large amount of liquid fuel remains in the vaporizer in the present embodiment.

FIG. 10 is a time chart showing a vaporizer temperature and a heating element control operation when ignition occurs in a conventional example.

FIG. 11 is a time chart showing a carburetor temperature and a heating element control operation when ignition is performed in a state where a large amount of liquid fuel remains in the carburetor in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vaporizer 2 Heating element 16 Temperature detection means 22 Timing means 23 Judgment means 1 Vaporizer 2 Heating element 3 Inner pipe 4 Front vaporization chamber 5 Rear vaporization chamber 6 Medium pipe 7 Outer pipe 8 Vent 9 Nozzle 10 Spouting pipe 11 Solenoid DESCRIPTION OF SYMBOLS 12 Valve rod 13 Heat transfer cylinder 14 Small passage 15 Filler 16 Temperature detection means 17 Burner 18 Tank 19 Oil feed pump 20 Oil feed pipe 21 Control unit 22 Clocking means 23 Judgment means 24 Combustion control means 25 26

Claims (2)

[Claims] 1. A vaporizer for vaporizing a liquid fuel, a heating element for heating the vaporizer, and temperature detecting means for detecting a vaporizer temperature, wherein the liquid fuel is supplied to the vaporizer to be vaporized and burned. In the vaporization control device for a vaporization type combustor, the time elapses from the time when the heating element is energized to the time when the temperature detected by the temperature detection means reaches a first predetermined temperature; and The minimum time required to accumulate the amount of heat that can start operation is the reference preheating time,
When the time measured by the time measuring means is equal to or shorter than the reference preheating time, the power supply to the heating element is stopped for a predetermined time, and then, when the vaporizer temperature has reached a second predetermined temperature, a combustion operation is performed. A vaporization control device for a vaporization-type combustor, wherein a determination unit is provided to start the operation and to re-energize the heating element when the temperature has not reached a second predetermined temperature. 2. The time for re-energizing the heating element is equal to or longer than the remaining time obtained by subtracting the time measured by the timer from the reference preheating time, and the vaporizer temperature is reduced within the re-energizing time. 2. The vaporization control device according to claim 1, wherein the combustion operation is started when the temperature reaches the second predetermined temperature.