JP4291781B2 - Combustion equipment - Google Patents

Description

  The present invention relates to a combustion apparatus that burns liquid fuel, and more particularly to a combustion apparatus that has a main tank outside the apparatus, pumps the liquid fuel from the main tank by a pump, and supplies the fuel tank to the fuel tank inside the apparatus.

  Conventionally, in a combustion apparatus that pumps liquid fuel from a main tank installed outside by a pump and supplies it to the fuel tank inside the apparatus, the liquid level of the liquid fuel supplied to the fuel tank is set to a float switch, etc. The operation of the pump is controlled by detecting by the liquid level detecting means.

  That is, since the driving timing of the pump is based on the detection signal of the float switch, if the float switch does not operate correctly, the pump will pump excessive fuel and the fuel will overflow from the fuel tank, causing a fire or the like. Therefore, in consideration of safety, a plurality of float switches are provided, or a plurality of operating points are provided in one float switch to detect an abnormal rise in the liquid level.

  FIG. 5 shows the configuration of a conventional combustion apparatus.

  The fuel tank 21 for storing liquid fuel is connected to a main tank (not shown) and an oil feeding pipe 22, and a pumping pump 23 for pumping the liquid fuel in the main tank to the fuel tank 21 is provided in the middle of the oil feeding pipe 22. ing. A pump drive unit 24 for driving the pumping pump 23 and a microcomputer 27 for controlling the operation of the pump drive unit 24 are provided.

  The fuel tank 21 is provided with a first float switch 25 and a second float switch 26 as means for detecting the liquid level in the fuel tank 21. Further, the first float switch 25 and the second float switch 26 have reed switches 28a, 28b, 28c that detect the liquid level of the fuel tank 21 and turn it on / off. 27.

  Next, the operation in the above configuration will be described. When the liquid fuel in the fuel tank 21 is consumed by combustion and the liquid level falls below a predetermined lower limit value, the first float switch 25 is activated and the reed switch 28a is turned on, and this signal is sent to the microcomputer 27. In response to this signal, the microcomputer 27 sends a signal to the pump driving means 24 to drive the pumping pump 23.

  The liquid fuel is supplied from the main tank to the fuel tank 21 through the oil feed pipe 22 by driving the pumping pump 23. When the liquid level of the fuel tank 21 reaches a predetermined upper limit value, the reed switch 28b is turned on. When the microcomputer 27 receives a reed switch ON signal, the microcomputer 27 controls the pump driving means 24 to stop driving the pumping pump 23. . As a result, the supply of the liquid fuel to the fuel tank 21 is stopped.

If the first float switch 25 fails and the reed switch 28b does not turn ON even if the liquid level exceeds a predetermined upper limit value, the liquid level will rise further. The rise is detected by the second float switch 26, and when the reed switch 28c is turned on, this signal is sent to the microcomputer 27 so that the pumping pump 23 is stopped.
JP-A-9-26165

  By providing a plurality of float switches in this way, even if one of them malfunctions or becomes clogged with dust, it can reliably detect the liquid level and stop driving the pump. It is configured as follows.

  However, there is no guarantee that both float switches will not operate normally. In the unlikely event that the reed switches 28b and 28c that detect the upper limit of the liquid level of both float switches are not turned ON, the pumping pump continues to supply liquid fuel to the fuel tank. It will overflow and cause a fire.

  The present invention is to solve the above-mentioned problems, and provides a highly safe combustion apparatus that can reliably stop the pumping pump and prevent fuel leakage even when the liquid level detecting means fails. For the purpose.

The present invention relates to a fuel tank for storing liquid fuel, a pump for pumping fuel into the fuel tank, pump drive means for driving the pump, and liquid level detection means for detecting the liquid level in the fuel tank. And a microcomputer for controlling the pump driving means by a detection signal of the liquid level detecting means, a burner portion for burning liquid fuel, and a flame detecting means for detecting a flame formed by the burner portion When the liquid level detecting means does not detect that the liquid level has exceeded the first predetermined value even after the first determination time has elapsed after the pump has driven the pump, the temporary running out determination is performed. The combustion apparatus is characterized by stopping driving of the pumping pump and stopping the combustion by performing a fuel shortage determination when the flame detecting means detects no flame.

  Further, the first determination time is a time during which liquid fuel does not overflow from the fuel tank even when the pump is further driven when the liquid level of the fuel tank is at a position where the operation of the pump is stopped. The combustion apparatus according to claim 1.

  The combustion apparatus according to claim 1, further comprising a notifying unit that notifies the user that the fuel has run out when the microcomputer performs a fuel shortage determination and stops combustion. is there.

  In addition, when the microcomputer receives the operation instruction for the first time after performing the fuel shortage main determination and stopping the combustion, the time for performing the fuel shortage temporary determination is set as the second determination time longer than the first determination time. It is a combustion apparatus of Claim 1 to 3 characterized by the above-mentioned.

Further, the second determination time is a time when the liquid level of the fuel tank becomes equal to or more than a first predetermined value after the pump is driven in a state where the microcomputer has determined that the fuel has run out. A combustion apparatus according to claim 4.

  6. The combustion apparatus according to claim 1, further comprising pump drive means input liquid level detection means for stopping the operation of the pump drive means without using a microcomputer.

  Since the present invention is configured as described above, it is possible to reliably stop the pumping pump when the liquid level detecting means fails, and the liquid level detecting means fails when there is sufficient fuel in the fuel tank. Even when the operation of the combustion apparatus is started without noticing that the oil is leaking, oil leakage due to excessive pumping of fuel can be prevented, so that the combustion apparatus is excellent in safety.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode of the present invention, which is considered preferable, will be briefly described by showing the effects of the present invention.

  In the present invention, when the liquid fuel in the fuel tank is below a predetermined amount and the liquid level detecting means detects no fuel, the pump is driven to supply the liquid fuel from the main tank outside the apparatus to the fuel tank. When the liquid level detecting means continues to detect the absence of fuel even after the first determination time has elapsed since the pumping pump is driven, a temporary determination of fuel shortage is made and the pumping pump is started. The driving is stopped, and then, when the flame detection means determines that there is no flame, the determination of running out of fuel is performed, and the operation of the combustion apparatus is stopped.

  That is, when the pump is driven, liquid fuel is supplied to the fuel tank. Therefore, if the liquid level detecting means is operating normally, the fuel should be detected after a while. However, in the case of failure, the liquid level detection means cannot detect the fuel. Therefore, if the liquid level detection means does not detect the fuel even after the first determination time has elapsed after the pump is driven, it is assumed that the liquid level detection means may be out of order. A temporary determination is made, and the pump is stopped to prevent further fuel supply.

  Therefore, it is possible to prevent the pumping pump from continuing to supply liquid fuel and overflowing from the fuel tank when the liquid level detecting means has failed.

  Further, when the fuel exhaustion temporary determination is made as described above and the pumping pump is stopped, sufficient liquid fuel remains in the fuel tank. If the combustion is stopped in this state, when the user issues a combustion start instruction without noticing that the liquid level detection means has failed, the pump is driven and the fuel tank is overloaded. There is a risk that fuel will be supplied and fuel will overflow.

  Therefore, after the pump is stopped, combustion in the combustion section is continued and fuel in the fuel tank is consumed, and combustion in the combustion section cannot be continued (the flame detection means is When it is determined that there is no flame, the final determination of running out of fuel is performed and combustion is stopped.

  Therefore, when combustion stops due to the fuel shortage judgment, there is very little liquid fuel remaining in the fuel tank, so the user is instructed to start combustion without noticing that the liquid level detection means has failed. Even if you put out the fuel, the fuel tank will not overflow.

  Specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a combustion apparatus according to the present invention. A main tank 1 provided outside the combustion apparatus, a fuel tank 2 for storing liquid fuel, and an oil feed pipe 3 connecting the main tank 1 and the fuel tank 2. A vaporizer 4 for vaporizing the liquid fuel, a burner unit 5 for burning the liquid fuel vaporized by the vaporizer 4, a flame detection means 6 for detecting a combustion flame formed by the burner unit 5, and a fuel tank 2 It has a fuel pump 7 for supplying the liquid fuel inside to the vaporizer 4.

  FIG. 2 is a block diagram of the portion related to the fuel supply, and controls the pump 8 for pumping the liquid fuel in the main tank 1 to the fuel tank 2, the pump driving means 9 for driving the pump 8, and the pump driving means 9. And a liquid level detection means (a liquid level detection means 11 for microcomputer input, a liquid level detection means 12 for pump drive means input) configured to detect the liquid level of the fuel tank 2.

  Normally, the driving of the pump 8 is controlled through the microcomputer 10 by a signal from the microcomputer input liquid level detection means 11, but for some reason, the microcomputer 10 cannot send a signal for stopping the pump drive means 9. When this occurs, the pump drive means input liquid level detection means 12 operates.

  FIG. 3 is a detailed view of the liquid level detection means described above. The liquid level detection means 11 for microcomputer input has a ring-shaped float 11a with a magnet embedded therein and a reed switch 11b. The float 11a rises / falls with the fluctuations of. When the liquid level is below the first predetermined value, the magnet embedded in the float 11a passes through the reed switch 11b, so that the reed switch 11b is turned on and a signal is sent to the microcomputer 10. The microcomputer 10 controls the pump driving means 9 by this signal to drive the pumping pump 8 for a predetermined time, and the level of the liquid level when the pumping pump 8 is driven for the predetermined time is H in the figure. Become.

  Similarly, the liquid level detecting means 12 for pump drive means input has a float 12a and a reed switch 12b, and the reed switch 12b is turned on when the liquid level exceeds a second predetermined value. The second predetermined value is set higher than the liquid level H when the reed switch 11b of the liquid level detecting means 11 for microcomputer input is operated and the pumping pump 8 is driven for a predetermined time. When it becomes impossible to send a signal for stopping the pump driving means 9 from 10 and the liquid level continues to rise, the reed switch 12b is turned on. Then, the signal is directly sent to the pump driving means 9, and the power switch 13 of the power source for driving the pumping pump 8 is turned off.

  Next, the operation in the above configuration will be described.

  When there is a sufficient amount of liquid fuel in the fuel tank 2, the reed switch 11b of the microcomputer input liquid level detection means 11 is OFF and the pumping pump 8 is stopped.

  When the operation of the combustion apparatus is instructed, heating of the vaporizer 4 is started first. When the temperature reaches a temperature at which the vaporizer 4 can vaporize the liquid fuel, the liquid fuel stored in the fuel tank 2 is discharged. Pumped by the fuel pump 7 and supplied to the vaporizer 4. In the vaporizer 4, the liquid fuel is heated to form a vaporized gas, and this vaporized gas is supplied to the burner unit 5 so that the burner unit 5 performs combustion.

  Further, the combustion state of the burner unit 5 is monitored by the flame detection means 6, and the flame detection means 6 detects the presence or absence of flame by the flame current in the combustion flame, and the detection signal is sent to the microcomputer 10.

  When combustion is performed in the burner unit 5, the liquid fuel in the fuel tank 2 is consumed, so that the float 11a descends accordingly. When the liquid level falls below the first predetermined value, the reed switch 11b of the liquid level detecting means 11 for microcomputer input is turned on, and this signal is sent to the microcomputer 10. Then, the microcomputer 10 determines that the liquid fuel in the fuel tank 2 has decreased, sends a signal to the pump drive means 9 to drive the pumping pump 8, and the pumping pump 8 is activated so that the liquid fuel in the main tank 1 is discharged. It is sent to the fuel tank 2 through the oil feeding pipe 3.

  The control when the pumping pump 8 is driven will be described using the flowchart of FIG.

  When the pumping pump 8 is driven and the supply of liquid fuel to the fuel tank 2 is started due to a decrease in the fuel in the fuel tank 2 (step 1), the microcomputer 10 starts measuring time (step 2). Then, it is determined whether the liquid level detection means 11 for microcomputer input detects liquid fuel (step 3). If the liquid fuel is not detected, whether the time measured has passed the first determination time T1. Is determined (step 4).

  If there is liquid fuel in the main tank 1 and the liquid level detecting means 11 for microcomputer input is operating normally, the liquid level in the fuel tank 2 is set to the first predetermined level before the first determination time T1 elapses. Since the value exceeds the value and the reed switch 11b is turned off, the liquid level detecting means 11 for microcomputer input should detect the liquid fuel. Therefore, in this case, the driving of the pumping pump 8 is continued as it is.

  Further, the microcomputer 10 determines the time to be counted by the microcomputer 10 (step 5), and when the predetermined time has elapsed, the microcomputer 10 sends a signal to the pump drive means 9 to stop the driving of the pumping pump 8. Therefore, the supply of the liquid fuel to the fuel tank 2 is stopped (step 6), and the combustion is continued as it is.

  On the other hand, in step 4, if the reed switch 11b is not turned OFF even when the first determination time T1 has elapsed and the liquid level detecting means 11 for microcomputer input cannot detect the fuel, the liquid fuel in the main tank 1 is exhausted. It is conceivable that the liquid fuel cannot be detected because the fuel has run out or the liquid level detecting means 11 for microcomputer input has failed.

  Accordingly, the microcomputer 10 makes a provisional determination of running out of fuel (step 7) and sends a signal to the pump drive means 9 to stop the pumping pump drive 8 (step 8). Therefore, when the liquid fuel cannot be detected due to the failure of the liquid level detecting means 11 for microcomputer input, it is possible to prevent the liquid fuel from being supplied to the fuel tank 2 any more.

  Although the liquid fuel is actually left in the fuel tank 2, the first determination time T1 has elapsed even if the liquid level detecting means 11 for microcomputer input fails and the pumping of the liquid fuel is started. In order to prevent the liquid fuel from overflowing from the fuel tank 2 before the operation, the liquid level of the fuel tank 2 is at a position (liquid level H) where the liquid level of the fuel tank 2 stops the operation of the pumping pump 8. When the pumping pump 8 is further driven, the time is set such that the liquid fuel does not overflow from the fuel tank 2.

  If combustion is continued in this state, the liquid fuel in the fuel tank 2 is consumed, and eventually the liquid level of the fuel tank 2 becomes lower than the suction port of the fuel pump 7, and the fuel pump 7 sucks up the liquid fuel. The liquid fuel is not supplied to the vaporizer 4. Then, since no flame is formed in the burner unit 5, the flame detection means 6 determines that there is no flame (step 9).

  When the flame detection means 6 determines that there is no flame, the microcomputer 10 performs a fuel shortage determination (step 10) and stops the operation (step 11).

  If the liquid level detection means fails and the user starts combustion without noticing that, the microcomputer input liquid level detection means 11 cannot detect the fuel, so the process returns to step 1 and the pump 8 The liquid fuel is supplied to the fuel tank 2 by driving the fuel tank 2. However, when the fuel shortage determination is performed and the combustion is stopped, the liquid level in the fuel tank 2 is always lower than the suction port of the fuel pump 7. Therefore, even if the pumping pump 8 is driven, the fuel does not overflow from the fuel tank 2 and can be used safely.

  Then, a notification means (not shown) notifies the user that the fuel has run out (step 12). As a result, the user can supply fuel to the main tank 1.

  Further, when the microcomputer 10 performs the main determination of running out of fuel and stops the combustion, when the operation instruction from the user is received for the first time, the pumping pump 8 is driven and the liquid level detecting means 11 for microcomputer input is the liquid fuel. Is changed to a second determination time T2 that is longer than the first determination time T1.

  The second determination time T2 includes the time required for the liquid level of the fuel tank 2 to exceed the first predetermined value after the pump 8 is driven 8 in a state where the microcomputer 10 has determined that the fuel has run out. Is set.

  That is, when combustion is stopped due to the fuel shortage determination, the liquid level in the fuel tank 2 is lower than the suction port of the fuel pump 7, which drives the pumping pump 8 during normal operation. (The reed switch 11b of the liquid level detecting means 11 for microcomputer input operates) The liquid level is lower than the first predetermined value. Therefore, when the fuel is supplied to the main tank 1 and the operation is resumed, the liquid level does not reach the first predetermined value even if the pumping pump 8 is driven for the first determination time T1, so that the liquid for microcomputer input The surface detection means 11 cannot detect the liquid fuel, and the microcomputer 10 makes a temporary determination of running out of fuel.

  Therefore, only when the operation instruction is accepted for the first time after the fuel shortage determination is made, the determination time is set to the second determination time T2 (T1 <T2), so that the liquid level is surely set to the first predetermined value. Now, driving can be continued.

It is a block diagram of the combustion apparatus of this invention. It is a block diagram of the part in connection with the fuel supply of this invention. It is explanatory drawing of the liquid level detection means in this invention. It is a flowchart explaining operation | movement of this invention. It is a conventional block diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Fuel tank 5 Burner part 6 Flame detection means 8 Pumping pump 9 Pump drive means 10 Microcomputer 11 Liquid level detection means for microcomputer input 12 Liquid level detection means for pump drive means input

Claims (6)

A fuel tank for storing liquid fuel; a pump for pumping fuel into the fuel tank; pump drive means for driving the pump; liquid level detection means for detecting the liquid level in the fuel tank; and the liquid In a combustion apparatus comprising a microcomputer for controlling the pump driving means by a detection signal of a surface detecting means, a burner part for burning liquid fuel, and a flame detecting means for detecting a flame formed by the burner part, the microcomputer is If the liquid level detection means does not detect that the liquid level has exceeded the first predetermined value even after the first determination time has elapsed since the pump was driven, a temporary fuel shortage determination is performed and the pump A combustion apparatus, wherein driving is stopped and combustion is stopped by making a fuel shortage determination when the flame detecting means detects no flame.   The first determination time is a time during which the liquid fuel does not overflow from the fuel tank even when the pump is further driven when the liquid level of the fuel tank is at a position where the operation of the pump is stopped. The combustion apparatus according to claim 1.   3. The combustion apparatus according to claim 1, further comprising an informing unit that informs a user that the fuel is out of fuel when the microcomputer performs a main fuel out determination and stops combustion.   When an operation instruction is accepted for the first time after the microcomputer performs fuel dead main judgment and stops combustion, the time for performing fuel dead provisional judgment is set as a second judgment time longer than the first judgment time. The combustion apparatus according to claim 1. The second determination time is a time when the liquid level of the fuel tank becomes equal to or more than a first predetermined value after the pump is driven in a state where the microcomputer has determined that the fuel has run out. 4. The combustion apparatus according to 4.   6. A combustion apparatus according to claim 1, further comprising pump drive means input liquid level detection means for stopping the operation of the pump drive means without using a microcomputer.

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