JPH0412350Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fuel exhaustion detection system for a combustion device equipped with an electromagnetic pump that supplies liquid fuel to a burner.

(Prior art) Usually, in this type of combustion device, a level regulator and an electromagnetic pump are installed between the burner and the fuel tank, and the fuel from the fuel tank is maintained at a constant level by the level regulator. After that, it is supplied to the burner by an electromagnetic pump.

Further, as systems for detecting burner burnout due to fuel exhaustion, there are systems that use a flame rod to monitor the presence or absence of flame current, and systems that use optical sensors to optically monitor the flame. However, the former method is limited to combustion devices such as electric preheating burners that generate almost no soot when turned on and off, and the latter is limited to combustion devices such as gun-type burners where the flame shape is constant and does not change.

Therefore, the above-mentioned detection system cannot be used in combustion devices such as pot-type burners that produce soot and smoke when turned on and off, or whose flame shape and color change depending on external factors such as temperature and wind. For this reason, in pot-type combustion devices, a temperature switch is provided on the burner side to detect fuel exhaustion based on a decrease in burner temperature after the flame has gone out, and to stop the electromagnetic pump based on this detection signal.

(Problem to be solved by the invention) However, in the case of a detection system using a temperature switch, the temperature switch does not operate from the time the burner flame goes out until the temperature drops. In other words, there is a disadvantage that there is a time delay of more than 10 minutes in detecting fuel exhaustion.

This invention was made in view of such circumstances,
The objective is to provide a fuel exhaustion detection system for a combustion device that can quickly detect fuel exhaustion.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a leveler for maintaining the fuel from the fuel tank at a constant level, a burner for combustion, and a leveler for maintaining the fuel from the fuel tank at a constant level. In a fuel exhaustion detection system for a combustion device that has an electromagnetic pump that supplies fuel to a burner, a vibration sound sensor converts the dry running sound of the electromagnetic pump due to fuel exhaustion into a predetermined electrical signal, and a detection signal from the vibration sound sensor is used. control means for stopping the electromagnetic pump based on the

(Function) In the fuel exhaustion detection system of the present invention, when the fuel in the oil level gauge is below a certain level or empty and air gets mixed into the electromagnetic pump, causing dry running, the vibration sound sensor detects this dry running. The sound is detected and a signal is sent to the control means, which stops the electromagnetic pump.

(Example) FIG. 1 shows a twin burner type combustion device to which the present invention is applied. This combustion device includes an oil level regulator 1, electromagnetic pumps 2, 2', oil pipe 3,
3', pot-type burners 4, 4', a branch pipe 5, a return pipe 6, a bypass pipe 7, and a valve shaft 8 for power outage.The oil level regulator 1 is connected to an external fuel tank (not shown). ing.

The oil level regulator 1 always maintains the fuel from the fuel tank at a constant level using a built-in float and a valve (not shown). Oil feed pipes 3, 3' are connected to the sides and above the oil level regulator 1 via electromagnetic pumps 2, 2' for fuel transfer, and the other end of each oil feed pipe 3, 3' is used for stove heating. burner 4 and burner 4' for hot water heating.

Both oil feed pipes 3 and 3' are partially connected by a branch pipe 5, and a return pipe 6 and a bypass pipe 7 branched from the oil feed pipe 3 enter into the oil level regulator 1. Further, a valve shaft 8 for power outage is installed at the branch point of the oil feed pipe 3 and the bypass pipe 7, and the valve shaft 8 normally closes the bypass pipe 7.

This valve shaft 8 rises during a power outage and opens the bypass pipe 7, so that even if the electromagnetic pumps 2 and 2' stop, the fuel 9 from the oil level regulator 1 is sent to the burner 4 through the hole 7a and the bypass pipe 7. It's starting to become easier. In addition, the return pipe 6 is used to return excess fuel 9 to the oil level regulator 1 when the fuel 9 in the burners 4, 4' exceeds a certain level, so that even if there is an ignition error, the burner 4, 4', etc. The fuel 9 does not overflow from each of the small holes 10, 10' of 4'.

FIG. 2 shows the circuit of the out-of-fuel detection system. This circuit consists of piezoelectric pickup 1
1 and 11', an amplifier 12, a microcomputer 13, a combustion control circuit 14, an electromagnetic pump 2 and 2', and an alarm lamp 15.

The piezoelectric pickups 11 and 11' are sensors whose crystals distort when sound pressure acts on them and generate an electric charge proportional to the sound pressure.When air is sucked into each electromagnetic pump 2 and 2' due to fuel shortage and dry firing occurs, a predetermined The detection signal is sent out.

The microcomputer 13 normally drives the electromagnetic pumps 2, 2' through the combustion control circuit 14 by outputting an oil feed command pulse (FIG. 3) to each electromagnetic pump 2, 2'. Furthermore, the electromagnetic pumps 2, 2' are stopped and the alarm lamp 15 is turned on in response to detection signals from the piezoelectric pickups 11, 11'. In addition, microcomputer 13
As is well known, intermittent combustion control is performed based on a signal from an indoor temperature sensor (not shown).

The fuel exhaustion detection system of this embodiment configured as described above operates as follows.

First, turn on the power to the combustion device and burner 4,
When the burner 4' is ignited, each electromagnetic pump 2, 2' sends a certain amount of fuel 9 from the oil level regulator 1 to the burner 4, 4' via the oil feed pipe 3, 3', and combustion is started. The burner 4 heats the room in which the combustion device is installed, and the burner 4' forms hot water which is sent to each room through pipes (not shown).

During this time, the fuel 9 in the oil level regulator 1 is maintained at a constant height by the above-mentioned float and valve, and the electromagnetic pumps 2, 2' normally transport the fuel without running dry.

When the fuel 9 in the oil level regulator 1 decreases due to the above combustion and its level becomes lower than the inlet of the oil feed pipes 3, 3', air is sucked into the electromagnetic pumps 2, 2', and as shown in FIG. Dry-beating vibrations as shown occur periodically. This vibration is caused by the piezoelectric pickups 11, 1
1', the signal is detected one or more times, amplified by an amplifier 12, and sent to a microcomputer 13.

Based on this detection signal, the microcomputer 13 stops the oil feed command pulse to stop each electromagnetic pump 2, 2', and at the same time turns on the alarm lamp 1.
Turn on 5.

In this way, in the above embodiment, when the fuel 9 in the oil level regulator 1 is less than a certain level or becomes empty, air gets mixed into the electromagnetic pumps 2, 2', causing dry pumping. Therefore, compared to conventional systems that detect burner temperature, fuel exhaustion can be detected more quickly.

In addition, since the electromagnetic pumps 2, 2' are stopped immediately after dry firing is detected, there is no possibility that half-finished fuel will not be supplied to the burners 4, 4' and unstable combustion will continue thereafter. .

Moreover, almost at the same time as the fuel runs out, the electromagnetic pump 2,
2' is stopped, even if fuel is refilled, the fuel is not supplied to the heated burners 4, 4', thereby preventing hot ignition after replenishment.

In addition, in Figure 3, there is a slight time delay from the occurrence of dry firing vibration to the stop of the fuel feed command pulse, but with pot-type burners, it takes several minutes from the time the fuel supply stops until the complete extinguishment. Since it takes time, the time delay in this embodiment is negligibly small.

Further, in the above embodiment, piezoelectric pickups 11, 11' are used as vibration sound sensors, but other sensors such as capacitance type sensors can also be used.

(Effects of the invention) As detailed above, according to the invention, when air enters the electromagnetic pump and causes dry running, this is detected as fuel exhaustion, so burner temperature can be detected. It has the advantage of being able to quickly detect when fuel runs out compared to conventional systems.

In addition, since the electromagnetic pump is stopped immediately after dry firing is detected, there is an advantage that half-finished fuel is not supplied to the burner and unstable combustion does not continue thereafter.

[Brief explanation of the drawing]

Fig. 1 is a simplified diagram of a combustion device to which the fuel-out detection system of the present invention is applied, Fig. 2 is a circuit diagram of the detection system, and Fig. 3 is a graph of the correspondence between the oil supply command pulse and the dry vibration of the electromagnetic pump. . In the figure, 1...Oil level regulator, 2, 2'...Electromagnetic pump, 3, 3'...Oil pipe, 4, 4'...Burner, 9
...Fuel, 11,11'...Piezoelectric pickup,
13...Microcomputer.

Claims (1)

[Scope of claim for utility model registration] (1) A leveling device that maintains fuel from a fuel tank at a constant level, a burner for combustion, and an electromagnetic pump that supplies fuel from the leveling device to the burner. In a fuel exhaustion detection system for a combustion device, the system comprises: a vibration sound sensor that converts the dry running sound of an electromagnetic pump due to fuel exhaustion into a predetermined electrical signal; and a control means that stops the electromagnetic pump based on the detection signal from the vibration sound sensor. A fuel exhaustion detection system for a combustion device, comprising: (2) The fuel exhaustion detection system for a combustion device according to claim (1), wherein the vibration sound sensor is a piezoelectric pickup. (3) The fuel exhaustion detection system for a combustion device according to claim (1), wherein a warning lamp indicating fuel exhaustion is connected to the output side of the control means.