JPS6030408B2 - Oil combustor fuel control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for automatically controlling the amount of fuel supplied at the time of ignition in an oil combustor, such as a pot-type combustor, that burns liquid fuel such as kerosene. For example, a hot air heater is suitable.

When igniting an oil combustor, especially a pot-type oil combustor, there is little combustion heat, so when igniting it, it is best to supply as little fuel as possible and let it burn gradually, and then increase the amount of fuel supplied to the normal level after the combustor has warmed up sufficiently. is considered desirable.

Conventionally, as a device for this purpose, one is known that is equipped with a detector that responds to combustion heat and adjusts the amount of fuel supplied in response to the detection signal (temperature). However, known devices either have a plurality of detectors and determine the amount of fuel supplied in response to each detector, or alternatively have a detector that generates an electrical signal that varies proportionally depending on the fuel heat. However, the electric signal is proportionally amplified to control the amount of fuel supplied, and there is a problem in that the wiring of the detector or the configuration of the control circuit becomes complicated. The present invention simplifies the control itself by regulating the fuel supply at ignition in predetermined increments using an electrical control device, requiring only one detector and thus requiring only a small number of detector wires. The object of the present invention is to provide an ignition control device that can be used without any problems.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows a schematic overall configuration of a hot-air heater to which the control device of the present invention is also applied, in which 1 is a pot-shaped combustor, la is a combustion chamber of this combustor, and 2 is a combustion gas of combustor 1. Heat exchangers 3a and 3b are blowers for indoor air circulation used for heating, and are designed to suck air from the upper part of the room through suction ports 3c and 3d. Reference numeral 4 denotes an electric motor that drives both blowers 3a and 3b, 5 a blower that supplies combustion air to the combustor 1, 6 a blower that discharges combustion gas (exhaust gas) to the outside, and 7 these blowers 5 and 6.
8 is a float-type fuel metering device that adjusts the flow rate of fuel (kerosene) supplied to the combustor 1. A float 8a opens and closes a valve 8b to keep the fuel level at a constant level. It is of a structure that maintains

Reference numerals 9a and 9b are metering nozzles provided in each of two parallel discharge passages provided in this fuel metering device 8, and one metering nozzle 9a is used to control the first set oil amount (for example, 3 cc/m).
in) for adjustment, and the other metering nozzle 9b is for adjusting the second set oil amount (for example, 5.5 cc/min).

10a and 10b are fuel supply electromagnetic valves provided in two discharge channels of the fuel metering device 8; 11 is a manual opening/closing valve that supplies fuel in the fuel tank 12 to the fuel metering device 8; A solenoid valve may be used if necessary.

Reference numeral 13 denotes a fuel supply port closed to the combustion chamber la of the combustor 1, and fuel is supplied to the solenoid valve 10a or 10b, and if necessary, when both are engaged, the fuel is supplied according to the opened solenoid valve. quantity is supplied to the combustion chamber la.

14 is an igniter for igniting the fuel supplied to the combustion chamber la, and is composed of an electric heater.

15 is an ignition transformer that controls the power supplied to the igniter 14, and 16 is a bimetallic heat-responsive switch installed in or near the heat exchanger 2, which starts combustion until the temperature reaches a predetermined temperature (for example, 70 oo). It has a normally open contact that closes when it rises.

Reference numeral 18 is an electrical control box located in a location that is not exposed to high temperatures.

Reference numeral 19 denotes a box forming the heater, and a hot air outlet for heating is provided at the lower front of the box 19.

21 is a combustion air intake pipe connected to the intake side of the blower 5; 22 is an exhaust gas discharge pipe connected to the discharge side of the blower 6; 23 is an air supply/exhaust top installed outdoors; , 22 are closed to the atmosphere.

Next, an electric control device will be explained. Since various documents have introduced various types of control devices for combustion type heating devices using digital computers, here, we will mainly explain ignition control. In FIG. 2, 18a is a digital computer called a microcomputer, which receives various input signals and outputs various command signals. The input signals include the opening/closing signal of the thermally responsive switch 16 and the opening/closing signal of the device activation switch 24. Further, the command signal includes a signal for commanding opening and closing of the metering valves 9a and 9b. 180 is a relay driving amplifier, 118c, 181d, 18e are relays, 18f, 18
g is a circuit that shapes the open/close signals from the switches 16 and 24.

Although not shown, a relay and a driving amplifier are provided to control the power supply to the electric motors 4 and 7. Next, the operation in the above configuration will be explained. First, the power switch (not shown) of the device is turned on, and the operation switch 24 is closed to operate the heater, and the digital computer 18a detects this. , performs various operation controls according to pre-built-in control programs. In this control program, ignition control is illustrated in FIG. First, the relay 18c is energized, and the electromagnetic valve 10a is opened by the electric control signal generated by the energization, and the minimum amount of fuel (3 cc/m) is supplied via the small metering nozzle 9a.
in) is supplied with fuel. Further, the igniter 14 is heated to red via the ignition transformer 15 with the relay 18e energized, and starts ignition operation (step 100). Also, energization to the motor 7 is started via a relay drive amplifier (not shown). Next, an internal timer function is started which measures time for 6 seconds (step 01). Next, it is repeatedly checked whether the thermal response switch (burner thermo) 16 is closed (step 102) and whether the internal timer is indicating the progress of 6 seconds (step 103). This check is repeated for the 6th stage/space. Therefore, the fuel supply is kept at a minimum during this 6-sand interval, and ignition is quickly carried out during this period. After 6 sands have passed,
Relay 18c is deenergized, relay 18d is energized instead, and only solenoid valve 10b is opened (step 104).

As a result, a medium amount of fuel (5.5 cc/min) is supplied through the large-diameter metering nozzle 9b.Furthermore, the internal timer function is restarted, and the air temperature on the outlet side of the heat exchanger 2 reaches the specified temperature. 6 sands have elapsed;
Third son. If there is no book, horse poem, zero, buri, etc., there will be a medium amount of fuel supply in the 6th sand room. Then, after six current stages have elapsed, the relay 18c is energized again, and the solenoid valves 10a and 10b are connected (step 108). As a result, the maximum amount of fuel is supplied (8.5 cc/min) via the two metering nozzles 9a, 9b. Next, an internal timer function that measures time for 30 seconds is started (step 109), and it is repeatedly checked whether the air temperature on the outlet side of the heat exchanger 2 has reached the specified temperature and whether 5 minutes have elapsed. (step 110,
111).

If the specified temperature is still not reached after 5 minutes due to failure of the igniter 14, fuel cut-off, etc., a combustion stop program (not shown) is executed and the igniter 14, electric motor 7, and electromagnetic The power supply to the valves 10a and 10b is cut off. However,
Check whether the thermal response switch 16 is always closed while the fuel supply amount changes from 4, medium, to large (step 1).
02,106,110), and if it is closed,
That is, if the air temperature on the outlet side of the heat exchanger 2 has reached 70 qo, the heat exchanger 2 is immediately operated according to the steady operation program (not shown), the power to the igniter 14 is cut off, and
The electric motor 4 starts to be energized and starts blowing out hot air.

Also, regardless of the previous state, the two solenoid valves 10a,
10b is energized and the maximum amount of fuel is continuously supplied. Here, since the combustor 1 is sufficiently heated, combustion continues stably. By sequentially increasing the fuel supply amount in this way, it is possible to quickly raise the combustion chamber temperature within a reasonable range of the fuel capacity.

To give an example of the experimental results, as shown in Figure 4, the ambient temperature T
The time Tm to reach the specified temperature for a could be reduced to about half compared to the constant fuel supply method (black circle).
Although the above-mentioned examples illustrate preferred embodiments of the present invention, the implementation of the present invention is not limited thereto.
Of course, the device of the present invention can be modified in various ways, and the structure of various switches, detailed circuit connections, etc. can be changed widely. Of course, it can be applied in exactly the same way.

Further, in the above embodiment, two electromagnetic valves 10 are used as fuel control valves, which are combined with two types of large and small metering nozzles 9a and 9b.
a and 10b are used, but when a solenoid valve whose function is adjustable is used, even one solenoid valve can control the fuel supply according to the opening and closing of the thermally responsive switch 16.

As described above, in the present invention, in an oil combustor that burns liquid fuel, the amount of fuel supplied is gradually increased over time until the temperature of the heat exchanger or its vicinity reaches a predetermined state. Since it is composed of one temperature detection means, fuel adjustment means, and electric control means, the fuel does not remain in liquid state at the time of ignition, and therefore it is possible to quickly shift to stable combustion without sudden combustion. I can do it,
Moreover, since the fuel supply amount is changed over time regardless of the individual values indicated by the detection signals of the temperature detection means, it is necessary to use multiple temperature detectors or particularly accurate detectors. This has the excellent effect of eliminating the need to adjust the gain of the control circuit that determines the amount of fuel supplied in response to the detection signal.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view illustrating a hot air heater to which the device of the present invention is applied, Fig. 2 is an electrical wiring diagram illustrating an embodiment of the device of the present invention, and Fig. 3 is a digital diagram in Fig. 2. A flowchart showing the main part of the computer control program, and FIG. 4 is a characteristic diagram showing an example of a performance test of the apparatus of the present invention. 1... Combustor, 2... Heat exchanger, 3a
, 3b... Circulating air blower, 4...
Electric motor, 5...Blower for combustion air, 7...
...Electric motor, 9a, 9b, 10a, 10b...
Metering nozzles 9a, 9b forming adjustment means and fuel supply solenoid valves 10a, 10b, 14...igniter, 16...
...Thermal response switch serving as temperature detection means, 18...
...Electric control box, 18a...Digital computer, 18b...Relay drive amplifier, 18c, 18d, 1
8e...Relay, 12...Fuel tank. Figure 1 Figure 3 Figure 4 Figure 2

Claims (1)

[Scope of Claims] 1. In an oil combustor that burns liquid fuel, an adjusting means for selecting and adjusting the amount of fuel supplied to the combustor from a plurality of stages in response to an electric control signal, and a heat exchanger. or a temperature detection means disposed near the temperature detection means that generates a temperature signal in response to the combustion heat, and a temperature detection means that receives the temperature signal of the temperature detection means and determines whether or not this temperature signal has reached a predetermined state. , characterized in that, while the determination result is negative, electric control means generates and applies the electric control signal to the adjustment means in order to gradually increase the amount of fuel supplied by the adjustment means over time. Fuel control device for oil combustor. 2. The device according to claim 1, wherein the adjusting means comprises a plurality of metering nozzles with different flow rates, and the electric control means selects a combination of opening and closing of the metering nozzles. .