JPH0399121A - Liquid fuel supply device - Google Patents

Abstract

PURPOSE:To prevent the generation of odor and reduce heating time during reignition by providing a return pump on the way of an oil supply pipe, and a bypass pipe, and driving the return pump for a specified time simultaneously when a fuel supply pump comes to a halt. CONSTITUTION:When a fuel supply electromagnetic pump 3 and a combustion fan 6 come to a stop, thereby effecting combustion stop operation, a return electromagnetic pump 11 is driven for a specified time, synchronizing with the suspending operation, which returns the fuel remaining in an oil supply pipe 4 and a nozzle 5 to a fuel tank 9 immediately by way of a bypass pipe 10. Therefore, this construction can prevent the fuel dripping from the nozzle 5 and the generation of odor with expansion caused by temperature rise near a vaporizer 2. Furthermore, it is possible to minimize a rise in the temperature of the vaporizer and hence reduce heating time during reignition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid fuel combustion apparatus in which liquid fuel is supplied to a burner section by a pump.

2. Description of the Related Art In general, a liquid fuel combustion device, for example, an oil combustor that uses kerosene as fuel, uses an electromagnetic pump 3 to pump kerosene into a vaporizing cylinder 2 heated to a constant temperature by a heater 1 or the like through an oil supply pipe 4 and It is blown through a nozzle 5, mixed with combustion air sent from a fan 6, turned into a vaporized gas, ignited, and combusted. After combustion, part of the combustion heat is recovered, the vaporization tube 2 is kept in a heated state, and the kerosene sent by the electromagnetic pump 3 is vaporized to continue combustion. In this case, since part of the combustion heat is recovered to heat the vaporizer cylinder 2, the oil pipe 4 and the nozzle portion 5 are exposed to a considerably high temperature. Since combustion air is being sent during combustion, there is no problem since there is some cooling effect, but when the combustion air stops blowing after combustion has stopped, the temperature of the oil pipe 4 and nozzle 5 rises extremely. Therefore, the kerosene in the oil pipe 4 and the nozzle 5 expands and falls into the vaporizer cylinder 2. This fallen kerosene is discharged as unburned gas, resulting in a phenomenon called odor generation. For this reason, in the past, a boss purge sequence was performed in which combustion air was continued to be fed after the combustion stopped until the temperature of the oil feed pipe 4 and nozzle 5 decreased. Problems to be Solved by the Invention With the above structure, the temperature of the oil pipe 4 and the nozzle 5 is lowered, and the temperature of the vaporizer cylinder 2 is also lowered.
This is a large loss in terms of heating to raise the vaporizing cylinder to a predetermined temperature during re-ignition.

Furthermore, since the fan 6 continues to rotate during the boss purge, there is also the problem that noise is generated due to the fan drive sound for a long time even when the combustion is stopped.

Furthermore, in addition to the temperature factor, the dripping of kerosene into the carburetor cylinder 2 after combustion is stopped may also be caused by the stop characteristics of the fuel supply pump 3. This type of pump generally uses a plunger pump powered by DC power, so even after the drive signal stops, the plunger moves once or twice before DC@5 is turned off, causing kerosene to flow out. there were.

For this reason, odor is generated due to the same phenomenon as described above. Conventionally, as a countermeasure for this problem, a complicated circuit structure has been required, such as adding a circuit to instantly turn off the DC power when the drive signal stops.

In view of the above-mentioned problems, the present invention has been developed to instantly return the kerosene in the oil pipe to the fuel tank after combustion has stopped, thereby preventing the generation of odor due to dripping of kerosene into the vaporization cylinder, and reducing the temperature of the vaporization cylinder after combustion has stopped. This minimizes the deterioration and shortens the heating time during re-ignition. Means for Solving the Problems In order to solve the above problems, the liquid fuel combustion device of the present invention provides a bypass path in the middle of the oil pipe that supplies fuel to the burner section, and connects the fuel tank from this bypass path to the fuel tank via a pump. By horizontally moving the return oil path and driving the return pump for a predetermined period of time in synchronization with the stop signal of the fuel supply pump, the oil accumulated in the oil pipe is forcibly returned to the fuel tank. This prevents kerosene from dripping into the vaporizer cylinder from the nozzle after combustion has stopped.

Operation The present invention has the structure described above, and at the same time when combustion is stopped, that is, when the fuel supply pump is stopped, the return pump is driven, and the kerosene accumulated in the oil pipe is forcibly returned to the fuel tank. For this reason, there is no kerosene in the oil pipe, and even if the temperature of the burner section rises a little after combustion has stopped, there is no problem of kerosene in the oil pipe dripping into the vaporization tube due to expansion, and no odor is generated. .

In addition, this eliminates the need for blowing combustion air, that is, the boss purge sequence that was used to cool the burner after combustion has stopped, and eliminates the need to forcibly lower the temperature of the vaporizer cylinder. The cylinder heating time can be shortened, and since the fan drive is eliminated, noise caused by the fan drive sound when combustion is stopped can be eliminated. Furthermore, any dripping of kerosene after the fuel supply pump stops is forcibly returned to the fuel tank by the return pump, so even if there is some dripping, it will not drip into the vaporization cylinder. Therefore, there is no need for an instantaneous stop circuit for the fuel supply pump.

EXAMPLE Hereinafter, a liquid fuel combustion apparatus according to an example of the present invention will be described with reference to the drawings.

In FIG. 1, l is a heater, 2 is a vaporization tube for vaporizing liquid fuel, 3 is an electromagnetic pump for supplying liquid fuel to the vaporization tube 2 via an oil feed pipe 4, and 5 is an oil feed pipe. A nozzle for spouting the liquid fuel sent from 4 to a predetermined position, 6 a combustion fan for supplying combustion air,
Reference numeral 7 indicates a blow pipe for guiding combustion air, 8 indicates an auxiliary tank, 9 indicates a fuel tank, 10 indicates a bypass pipe provided in the middle of the oil transfer pipe 4, and 11 indicates a route of the bypass pipe 10, and indicates that the oil transfer pipe 4 and This is an electromagnetic pump for returning the liquid fuel accumulated in the nozzle 5 to the fuel tank 9.

FIG. 2 is a flowchart showing the operation of the electromagnetic pumps 3 and 11.

The operation of the liquid fuel combustion apparatus configured as described above will be explained below.

First, the transition operation to the combustion state is performed based on a general ignition operation. Therefore, that part is also omitted in the flowchart. Next, the presence or absence of all stop signals such as operation switch, stop due to thermo-OFF, and abnormal stop is detected. If there is no signal, the combustion state continues, and if there is, the electromagnetic bomb 3 for fuel supply and the combustion state are detected. Stop the return fan 6, and turn off the return electromagnetic pump 1l.
is driven for a predetermined period of time. As a result, the fuel accumulated in the oil feed pipe 4 and the nozzle 5 is instantly returned to the fuel tank 9 via the bypass pipe 10, so that the fuel is transferred from the nozzle 5 due to expansion due to the temperature rise near the vaporization pipe 2 after combustion has stopped. The phenomenon of dripping is also eliminated, and no odor is generated. The return electromagnetic pump 1l is stopped after a predetermined period of time and returned to its initial state.

By performing this operation every time combustion is stopped, the problem of extinguishing odor can be solved.

Effects of the Invention As described above, the present invention eliminates fire extinguishing odors by providing a bypass pipe in the middle of the oil pipe and using a return pump to return the liquid fuel in the oil pipe and nozzle into the fuel tank after combustion has stopped. Able to solve problems. In addition, there is no need to supply combustion air after combustion has stopped, that is, to perform a boss purge, and there is no noise caused by fan drive when combustion is stopped, and the temperature of the carburetor cylinder does not drop much, so heating of the carburetor cylinder during re-ignition is reduced, and electricity consumption is reduced. It also has the effect of being cheaper.

[Brief explanation of drawings]

Figure 3 shows conventional liquid fuel combustion a@$4,Td,,. 3,11...Fuel supply and return pump,
4...Oil pipe, 9...Fuel tank, 1
o...Bypass pipe (bypass route).

Claims (1)

[Claims] A burner section that vaporizes and burns liquid fuel, a fuel supply pump that sucks fuel in a fuel tank and supplies it to the burner section, and a bypass path provided in the middle of an oil pipe that supplies fuel to the burner section. , a return pump installed in this bypass path to return the kerosene accumulated in the oil pipe into the fuel tank after combustion has stopped, and a fuel supply pump that controls the operation of the return pump and the fuel supply pump. a control means for outputting a signal to drive a return pump for a predetermined period of time in synchronization with a stop signal of the liquid fuel combustion apparatus.