JPH0914640A - Liquid fuel combustion device - Google Patents

Abstract

PURPOSE: To stabilize a combustion amount in a liquid combustion device such as a kerosene fan forced heater. CONSTITUTION: A liquid fuel combustion device feeds liquid fuel F in a liquid fuel tank A in a carburetor C by a pump B and a burner D to burn gasified fuel comprises a flame sensor 6 to detect conductivity of flame and output a signal responding to a combustion amount; and a pump drive control part to control a flow rate of the pump B by means of an output signal therefrom. This constitution prevents the occurrence of the mechanical change of a pump, and the change of a combustion amount occasioned by the increase of flow passage resistance due to accumulation of a solid in the fuel passage of the carburetor and stabilizes a combustion amount by controlling a flow rate of a pump. Further, since there is no need to individually regulate pumps, a manufacturing cost is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid fuel combustion apparatus used for heating, hot water supply, cooking and the like.

[0002]

2. Description of the Related Art Conventionally, a vaporization combustion system of supplying liquid fuel such as kerosene to a vaporizer by a pump, heating and vaporizing it, and then mixing and burning air is used for heating, hot water supply, cooking, etc. Widely used in.

The pump used in this case holds an intake port in a fuel tank, and a fuel flow path from the intake port to the discharge port is constituted, and a pulse is applied to an electromagnetic coil installed outside the fuel flow path. Pump that reciprocates the plunger in the fuel flow path by the magnetic force generated by repetitive supply of constant electric power, and supplies the fuel in the tank to the carburetor by the action of the check valve provided in the flow path. Is often used.

The vaporizer heats and vaporizes the liquid fuel supplied by a pump. As a heating heat source, a heater by electric power or self-combustion heat is used in combination with this heater.
The fuel vaporized by the vaporizer is mixed with air and burned by the combustor.

Now, in such a liquid fuel combustion apparatus, the flow rate of the pump is the combustion amount of the combustion apparatus,
It is important to fully demonstrate the performance of the equipment and ensure safety. However, it is difficult for the pump flow rate to realize the design target immediately with a large number of mass-produced pumps, so an adjustment process for adjusting the flow rate is performed for each pump, and as a result, the target is met. A method of obtaining the flow rate is implemented.

[0006] In this adjusting step, first, the flow rate of all pumps before adjustment, which are designed to have a flow rate higher than the target flow rate, is individually measured. Next, an adjustment resistor having a resistance value calculated from the relationship between the flow rate to be reduced and the supplied power is selected from the obtained difference between the measured flow rate and the target flow rate, and is selected and attached in series to the electromagnetic coil. Furthermore, the flow rate of the pump after adjustment is measured to confirm the flow rate of the finished product. The pump flow rate before the adjustment resistor is attached usually has a variation of about 30% with respect to the target flow rate, but after the attachment, it can be compressed to a variation of about 10%.

With the pump thus produced, it becomes possible to obtain a combustion device which can obtain a constant amount of combustion under certain conditions.
Under this basic characteristic, a combustion device that can freely control the combustion amount within a certain range is realized.

[0008]

Conventionally, the adjustment process performed to match the flow rate of the pump with the target is to measure the individual flow rate for all the pumps before the adjustment resistors are installed, and then measure the measured flow rate and the target flow rate. It is a complicated work to calculate the resistance value to be installed from the difference of the values, select the resistor of that resistance value and install it in the pump, and to measure the flow rate for confirmation, so it takes a lot of time, equipment and manpower. It had a problem of cost.

Further, in the above-mentioned conventional technique, the adjustment in the direction of decreasing the pre-adjustment flow rate is possible, but the adjustment in the direction of increasing the pre-adjustment flow rate is not possible. Therefore, the pre-adjustment flow rate is equal to the target flow rate. Pumps below 100% have drawbacks that cannot be applied.

Further, in order to adjust the flow rate of the pump, it is necessary to measure the flow rate at a constant drive pulse period, energization time, and voltage, while the drive pulse period, energization time, and voltage on the combustion device side are the combustion device. It was necessary for the side to make adjustments within the standard tolerance range.

Furthermore, it can be said that the flow rate under a certain standard condition is adjusted by adjusting the flow rate of the pump according to the above-mentioned prior art. However, when a new fuel is supplied to the fuel tank, the fuel viscosity due to the temperature is high. The problem that the flow rate of the pump increases or decreases, that is, the mechanical loss of the pump itself increases, or the flow resistance increases due to the accumulation of solids in the fuel flow path such as the carburetor, which reduces the flow rate over time. Has not been resolved.

The present invention eliminates the above-mentioned conventional drawbacks, improves the capacity of the combustion apparatus, and at the same time realizes significant cost reduction.

[0013]

A combustion apparatus of the present invention comprises a fuel tank, a pump which is driven by electric power, and which supplies liquid fuel in the fuel tank to a carburetor, and which is in communication with the discharge port of the pump. And a vaporizer for heating and vaporizing the liquid fuel supplied by the pump and a combustor connected to the vaporizer, and a flame sensor for detecting flame conductivity in the combustor, and a flame sensor for the flame sensor. A pump drive control unit for controlling the pump drive power based on the output is provided.

[0014]

In this type of combustion device, the flame sensor detects the presence of flame to confirm ignition at the time of ignition,
It has been used as a sensor for detecting misfire during combustion.

In the present invention, by utilizing the phenomenon that the flame conductivity changes depending on the amount of combustion, a flame sensor is used as a sensor for detecting the amount of combustion, and the output of this sensor is fed back to the pump drive control unit for pumping. The flow rate of the pump was adjusted by controlling the drive power supplied. The drive power control in this case is the pulse period,
It is possible to select any one of the energization time and the voltage, or a plurality of them, and it is possible to freely select and implement depending on the properties of the pump to be specifically used.

As a result, when there is a difference from the target flow rate in a pump that has not been subjected to conventional adjustment work, fuel temperature before vaporization, increase in mechanical loss of the pump, increase in resistance of fuel flow passage such as carburetor, etc. If the combustion amount changes due to
This change is detected by the flame sensor as a change in flame conductivity and is fed back to the pump drive control unit, so that the above change in the combustion amount can be corrected and held at the target combustion amount.

[0017]

EXAMPLE An example of the liquid fuel combustion apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall view of the essential part of the embodiment, in which A is a fuel tank, which comprises a fixed tank 1 and a cartridge tank 2.
Liquid fuel F in the fixed tank 1 is vaporized by a pump B into a vaporizer C.
Supplied to The vaporizer C heats and vaporizes the liquid fuel F by the heater 3, and ejects vaporized gas from the nozzle 4. D is a combustor which mixes vaporized gas and combustion air, and is ignited by an igniter 5 to burn. The combustor D is provided with a flame sensor 6 that detects the conductivity of flame and outputs a signal corresponding to the amount of combustion. Reference numeral 7 is a solenoid that opens and closes the nozzle 4 to control ejection of vaporized gas. Reference numeral E is a combustion control unit that controls each unit of the combustion apparatus.

FIG. 2 is a longitudinal sectional view showing the internal structure of the pump B of the embodiment shown in FIG. Here, 8 is a cylindrical cylinder, 9 is a suction cylinder connected to the lower part of this cylinder 8,
Reference numeral 10 is a suction port that opens at the lower end of the suction cylinder 9, 11 is a discharge joint connected to the upper portion of the cylinder 8, and 12 is a discharge port provided at the upper end of the discharge joint 11. The cylinder 8, the suction cylinder 9, and the discharge joint 11 are integrally formed to form a fuel flow path from the suction port 10 to the discharge port 12. Reference numeral 13 denotes a free piston-like plunger supported by a pair of support springs 14 and 15 so as to be capable of reciprocating inside the cylinder 8, 16 is a suction check valve arranged in the plunger 13, and 17 is a discharge check valve. A stop valve, 18 is an electromagnetic coil, 19 is a yoke, 20 and 21 are a pair of magnetic poles, and 22 is a terminal connected to the end of the electromagnetic coil 18.

In the above structure, when pulsed power is supplied to the electromagnetic coil 18, the electromagnetic coil 18 is supplied during the energization period.
Is excited to generate a magnetic flux, and the plunger 13 receives a magnetic attraction force to rise from the balanced state against the biasing force of the upper support spring 14. At this time, the liquid fuel F in the fixed tank 1 is sucked from the suction port 10 of the suction cylinder 9 and discharged from the discharge port 12. On the other hand, during the pulse pause period, the magnetic attraction force disappears, and the plunger 13 is pushed down by the repulsive force of the upper support spring 14. When the plunger 13 descends, the liquid fuel F in the suction cylinder 9 is introduced above the installation portion of the suction check valve 16. By repeating this operation, a fixed amount of the liquid fuel F is supplied from the fixed tank 1 to the carburetor C.

FIG. 3 is a vertical sectional view showing the internal structure of the vaporizer C of the embodiment shown in FIG. Reference numeral 23 denotes a fuel supply pipe, the lower end of which is connected to the discharge joint 11 of the pump B. A vaporization chamber 24 is provided with a porous body 25 for heat supply inside, and a heater 3 for heating and a thermistor 26 for temperature detection outside. 4 is a nozzle for jetting fuel into the combustor D, 27 is a return pipe whose lower end is arranged in the fixed tank 1, 28 is a solenoid coil, 29 is a magnetic material, 30 is a spring, 31 is a valve rod, and 32 is Needle valve 33 is a return valve.
These two valves are integrated with the magnetic body 29 by the valve rod 31, and when the solenoid coil 28 is energized, the magnetic body 29 is moved by the magnetic force to close the needle valve 32 and open the return valve 33, and the solenoid is closed. When the coil 28 is de-energized, the restoring force of the spring 30 causes the needle valve 32 to open and the return valve 33 to close.

FIG. 4 is a vertical sectional view showing the internal structure of the combustor D of the embodiment shown in FIG. Reference numeral 34 is an inlet from which vaporized fuel (indicated by a solid arrow) and air (indicated by a dashed arrow) supplied from the nozzle 4 of the carburetor C are introduced.
Reference numeral 35 is a mixing chamber in which the liquid fuel F and air are mixed, 36 is a flame opening portion, 37 is a combustion space, the igniter 5 is one that ignites by applying a high voltage during ignition and spark discharge, and the flame sensor 6 is a flame. It is a sensor that detects the conductivity of flame with the mouth 36 and outputs a signal.

FIG. 5 is a combustion control unit E of the embodiment shown in FIG.
FIG. The combustion control unit E includes a carburetor temperature control unit 38, a pump drive control unit 39, a combustion amount calculation unit 40, a solenoid control unit 41, and a signal from an operation switch 42, an oil detection sensor 43, a room temperature sensor 44, The operation of each part of the combustion device from ignition to combustion and extinction is controlled.

The carburetor temperature control unit 38 controls the electric power of the heater 3 in accordance with the output of the thermistor 26 for detecting the temperature of the carburetor C to heat the carburetor C to a temperature sufficient to vaporize the liquid fuel F. And keep it at an appropriate temperature.

The combustion amount calculation unit 40 determines the combustion amount from the output of the flame sensor 6 and outputs a correction signal to the pump drive control unit 39 according to the difference from the set target combustion amount.

The pump drive controller 39 repeatedly supplies pulsed electric power to the electromagnetic coil 18 of the pump B, and controls the energization time, pause time and voltage of the pulse to control the liquid fuel F.
The amount of supply of is adjusted.

The solenoid control unit 41 opens / closes the needle valve 32 and the return valve 33 by turning on / off the energization of the solenoid coil 28 to switch the supply passage of the liquid fuel F.

FIG. 6 is a graph showing the relationship between the combustion amount and the output voltage. The relationship is that when the combustion amount increases, the flame conductivity increases and the output voltage increases. The combustion amount calculation unit 40 determines the combustion amount from the output voltage based on this relationship, converts the difference from the target combustion amount at that time into an increase or decrease of the driving power of the pump, and sends a correction signal to the pump drive control unit 39. Is output.

In the operation of this embodiment, when the operation switch 42 is turned on, the solenoid coil 28 is energized, the needle valve 32 is closed and the return valve 33 is opened. next,
Supply of electric power to the heater 3 of the vaporizer C is started, and the vaporizer C
Is preheated. When the completion of preheating is detected by the thermistor 26, the drive of the pump B is started, the liquid fuel F is supplied to the vaporization chamber 24, and is heated and vaporized. At this time, the solenoid coil 28 is turned off and the needle valve 32 is opened.
The return valve 33 operates to close, the vaporized fuel is ejected from the nozzle 4 as a high-speed flow, is supplied to the combustor D while sucking the air in the adjacent space, and passes through the mixing chamber 35 to the combustion space from the flame port 36. Guided to 37. Since the igniter 5 has been repeatedly discharged from the time when the needle valve 32 is opened, it is ignited here to start combustion. When ignited, the flame sensor 6 detects a flame, the discharge of the igniter 5 is stopped, and thereafter, the combustion state is continued.

While the combustion is continuing, the flame sensor 6 detects the flame conductivity, and when the combustion amount is judged from the output, the combustion amount according to the detection of the room temperature or the like, or the combustion amount selected and artificially forced, etc. By correcting the pump drive power toward the target combustion amount of, the controlled combustion amount can be continuously executed.

However, the above control is not effective for a short time until the first correction is performed immediately after the start of combustion. Therefore, in order to avoid the occurrence of a bad odor, soot, or a dangerous combustion state due to variation in the flow rate of the pump B during this time period, combustion exceeding the allowable combustion amount in the combustor D is performed. The pump drive power at the start is the drive power of the pump B considered from the basic performance of the pump B and the combustor D used, for example, the variation in the flow rate of each pump is ± the maximum allowable combustion amount of the combustor D.
In the case of 15%, even if the pump has a flow rate of + 15%, it is set to a value that does not exceed the maximum allowable combustion amount. With this drive power, the pump with a flow rate of -15% will start at a flow rate of about 70% of the maximum allowable combustion amount, but after the first correction is performed, the combustion rate will increase toward the target flow rate. The amount can be corrected.

For safety, the above target combustion amount is
It is effective to set the maximum value and the minimum value of the pump drive power that are allowed due to the characteristics of the pump, and perform the correction within that range.

As a result of operating the pump having a flow rate variation of 30% which is not adjusted in the above embodiment by the combustion apparatus of the present invention, the variation in the combustion amount is corrected and controlled within the range of 10% which satisfies the actual use, It was confirmed that stable combustion was achieved.

[0034]

As described above, the liquid fuel combustion apparatus of the present invention communicates with the fuel tank, the pump which is driven by electric power, and which supplies the liquid fuel in the fuel tank to the carburetor, and the discharge port of this pump. Equipped with a vaporizer that heats and vaporizes the liquid fuel supplied by the pump, and a combustor that is connected to the vaporizer, and a flame sensor that detects the flame conductivity in the combustor, Since the pump drive control unit that controls the drive power of the pump based on the output of the flame sensor is provided, the work of individually adjusting the flow rate of the pump in advance, the drive pulse cycle of the combustion device, the energizing time, and the voltage Eliminates the need for adjustment work within the tolerance range, and has the basic ability to automatically correct fluctuations in the flow rate of the pump in either the decreasing or increasing direction toward the target flow rate. Those having an effect capable of reducing the substantial cost of the adjustment.

Even if there is a change in the fuel viscosity, a change in the mechanical loss of the pump or the carburetor, or a change in the combustion amount due to a change in the resistance of the fuel flow passage, the change in the conductivity of the flame caused by the change is large. The pump driving power is adjusted accordingly to correct the combustion amount and maintain a constant amount.

[Brief description of the drawings]

FIG. 1 is an overall view of a main part of a liquid fuel combustion apparatus according to a first embodiment of the present invention.

2 is a vertical cross-sectional view showing the internal structure of a pump B of the embodiment shown in FIG.

FIG. 3 is a vertical cross-sectional view showing the internal structure of the vaporizer C of the embodiment shown in FIG.

4 is a vertical cross-sectional view showing the internal structure of the combustor D of the embodiment shown in FIG.

5 is an internal configuration diagram of a combustion control unit E of the embodiment shown in FIG.

FIG. 6 is a graph showing the relationship between the output voltage of the flame sensor and the combustion amount.

[Explanation of symbols]

 A fuel tank B pump C vaporizer D combustor E combustion control unit F liquid fuel 1 fixed tank 2 cartridge tank 3 heater 4 nozzle 5 igniter 6 frame sensor 7 solenoid 8 cylinder 9 suction cylinder 10 suction port 11 discharge joint 12 discharge port 13 Plunger 14, 15 Support Spring 16 Intake Check Valve 17 Discharge Check Valve 18 Electromagnetic Coil 19 Yoke 20, 21 Magnetic Pole 22 Terminal 23 Fuel Supply Pipe 24 Vaporization Chamber 25 Porous Body 26 Thermistor 27 Return Pipe 28 Solenoid Coil 29 Magnetic Body 30 Spring 31 Valve rod 32 Needle valve 33 Return valve 34 Inlet 35 Mixing chamber 36 Flame opening 37 Combustion space 38 Vaporizer temperature control unit 39 Pump drive control unit 40 Combustion amount calculation unit 41 Solenoid control unit 42 Operation switch 43 Oil detection Sen 44 temperature sensor

Claims (1)

[Claims] 1. A fuel tank, a pump which is driven by electric power and supplies liquid fuel in the fuel tank to a carburetor, and a pump which is provided in communication with a fuel discharge port of the pump and which supplies the liquid fuel supplied by the pump. A vaporizer that heats and vaporizes it, and a combustor that is connected to the vaporizer, and a flame sensor that detects flame conductivity in the combustor, and drive power for the pump based on the output of the flame sensor. A liquid fuel combustion apparatus characterized in that a pump drive control unit for controlling the above is provided.