JPH0646094B2 - Control device for hot air heater - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a hot air heater equipped with a vaporizing combustor.

Conventional technology Conventionally, the mixing ratio of the fuel oil vaporized in the combustor and the combustion air has a slight fluctuation depending on the combustion amount such as strong combustion and weak combustion, but the optimum ratio is set beforehand when the combustor is designed. It has been determined that combustion is always performed at a predetermined mixing ratio during ignition and during normal combustion.

FIG. 6 is a schematic diagram showing the structure of a conventional oil heating device.
Reference numeral 101 is a fuel tank, and the fuel oil is sucked up by an electromagnetic pump 102 and sent under pressure to a vaporizer 103. The vaporizer 103 is heated by the heat of combustion and the heater 104, and after the fuel oil is vaporized here, it is mixed with the combustion air supplied from the combustion air supply device 105 in the mixing chamber 106, and the flame port 107
Forms a flame 108. Burned exhaust gas is burned by a combustion tube 10
9. Heat is exchanged with the room air through the radiator 110 to heat the room and then exhausted to the outside.

FIG. 7 shows a conventional control circuit, where 111 is a power supply and 112
Is a control unit that performs combustion control by performing temperature control of the heater 104 and various timing controls such as relays. The control unit 112 first preheats the carburetor 103 by turning on the relay 113 at the start of operation, turns off the relay 113 when preheating is completed, and turns on the relay 114 to supply the combustion air supply device 105, the electromagnetic pump 102, and The igniter 115 is energized to ignite and burn. The combustion air supply device 105 is composed of a motor provided with taps a and b for selecting strong rotation and weak rotation, and the electromagnetic pump 102 is provided with terminals a ′ and b ′ capable of changing the discharge amount in two stages. It is assumed that

The relay 116 is a two-circuit two-contact relay, and this contact is a,
When closed to the side of a ', the combustion air supply device 105 is strongly rotated, and the electromagnetic pump 102 is determined to have a large flow rate, resulting in strong combustion. Conversely, when the contacts of the relay 116 are closed on the b and b'sides, weak combustion occurs.

As described above, the conventional control device for the warm air heater supplies and burns the predetermined combustion air and the fuel oil which are set in advance according to the combustion amount of the strong combustion or the weak combustion.

However, in the above-mentioned conventional configuration, the amount of combustion air supplied by the combustion air supply device 105 and the amount of fuel oil discharged from the electromagnetic pump 102 according to the amount of combustion are preset, When the mixing chamber 106 at the start of combustion is not sufficiently warmed up, a part of the vaporized fuel oil will condense before reaching the flame mouth 107, and thus odor will be generated by lift-like combustion. On the other hand, as the heat of combustion is recovered in the mixing chamber 106 and sufficient vaporized fuel oil is obtained, the combustion becomes yellow flame combustion, and soot is likely to be generated.

The present invention solves such a conventional problem, and by changing the mixing ratio of the combustion air and the fuel oil at the time of ignition depending on the carburetor temperature at the start of energization of the heater, it is possible to always obtain a stable ignition combustion state. The purpose is to

Means for Solving the Problems In order to achieve the above object, the controller of the hot air heater of the present invention is a carburetor temperature detecting means for detecting the temperature of a carburetor for heating and vaporizing fuel oil, and a preheating operation start time. A configuration is provided that includes a combustion control unit that changes the mixing ratio of the vaporized fuel oil and the combustion air at the time of ignition according to the carburetor temperature.

Effect The present invention has the above-described configuration to estimate the amount of vaporized fuel oil dew condensation in the mixing chamber from the carburetor temperature at the start of preheating, and mix so as to change the ratio of the amount of combustion air to the amount of fuel oil at ignition. As a result, stable ignition and combustion will be achieved regardless of the temperature at the flame tip.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of the present embodiment composed of a burner using an opposing flame, and FIG. 2 is a view of a horizontal cross section of the burner as seen from above. 1 is an outer frame, 2 is a fuel tank, 3 is an electromagnetic pump in which the amount of fuel discharged changes according to the applied pulse frequency, and is ejected to a burner 5 via a nozzle 4. Reference numeral 7 denotes a combustion air supply port for supplying combustion air from the periphery of the nozzle 4 and communicates with the combustion air supply device 6. Reference numeral 8 denotes a vaporizer formed in a slender shape, and a heater 9 embedded in the bottom portion vaporizes the fuel. Reference numeral 10 is a mixing chamber for mixing the vaporized combustion oil vaporized by the vaporizer 8 with combustion air, and also serves as a passage for supplying the mixed gas to the combustion section 11. Reference numeral 12 is a vaporizer temperature detector for detecting the temperature of the vaporizer 8 and is attached to the bottom of the vaporizer 8. An electric signal obtained by converting the temperature detected by the vaporizer temperature detector 12 is input to the control device 16. Reference numeral 13 is a flame port provided in the combustion section 11. The mixed gas ejected from the flame port 13 forms a flame 14, and the flame formed is a frame rod.
It is detected at 14a.

The controller 16 includes a carburetor temperature detecting means 17 for judging the temperature of the carburetor 8 detected by the carburetor temperature detector 12, and an electromagnetic pump control means 18 for outputting a pulse signal corresponding to the combustion amount to the electromagnetic pump 3. A combustion air control means for controlling the rotation speed of the combustion air supply device 6 to a predetermined rotation speed
19, an ignition detection unit 14b that determines the presence or absence of ignition based on a signal from the frame rod 14a, and the electromagnetic pump control unit 18 and the combustion air control unit 19 to the combustion sequence via a signal line S1 or S2, respectively. And a combustion control unit 20 for instructing a predetermined value corresponding thereto.

The signal line S1 is an output signal that changes according to the information from the carburetor temperature detecting means 17, and the signal line S2 is an output signal that changes according to the combustion amount. The combustion air control means 19 selectively inputs the signal lines S1 and S2 by a switch 14c that switches between the outputs of the ignition detection section 14b.

FIG. 3 shows an example of a concrete circuit of the main part. Controller 16
Is composed of a microcomputer 21 and peripheral circuits. The microcomputer 21 shown here is a CP
It is a so-called one-chip microcomputer having a U, a ROM, a RAM and an input / output unit. The vaporizer temperature detector 12 is A
It is connected to the input section of the microcomputer 21 via the / D converter 22. As a result, the temperature signal from the vaporizer temperature detector 12 is converted into a binary code and read into the microcomputer 21. Reference numeral 23 denotes an operation switch for instructing the start of combustion, which is input to the microcomputer 21. twenty four
Is a zero-cross detection circuit that detects a zero-cross point of the AC signal source 25 synchronized with the power supply frequency and generates a pulse signal having a width of about 1 ms. The microcomputer 21 determines the zero-cross point based on this pulse signal. Reference numeral 26 denotes a semiconductor switch, which is composed of an LED of a light emitting portion and a triac of a light receiving portion. 27 is a relay for turning on / off the heater 9, and 28 is an igniter. Reference numeral 29 denotes a variber, which drives the semiconductor switch 26, the relay 27, the electromagnetic pump 3, and the igniter 28, which are connected to the output, by receiving an output signal from the microcomputer 21.

On the other hand, the AC power source 30, the heater 9 via the contact 27a of the relay 27, and the combustion air supply device 6 via the semiconductor switch 26.
Are connected in parallel. The rotation speed of the combustion air supply device 6 is detected by the rotation detector 31, and the microcomputer 21 performs feedback control of the rotation speed based on this rotation information.

Next, the operation of this embodiment configured as described above will be described with reference to the flowchart of FIG. Whether the operation switch 23 is on or off is determined in step 35. First, assuming that the combustion is currently being performed, when the operation switch 23 is turned off, the process flows in the direction i, the combustion is stopped in step 36, and then the one-minute timer is started in step 37. This one
The minute timer shall be updated in step 34.
Next, when the operation switch 23 is turned on again, first, at step 38, it is checked whether or not the 1-minute timer is up. That is, when the operation switch 23 has been off for less than 1 minute, the process flows in the direction B, and in step 39 the combustion air supply device 6 is turned on for cooling the carburetor.

When the 1-minute timer times out, the combustion air supply device 6 is once turned off in step 39 ', and then in step 40, the heater temperature detector 12 detects the temperature of the carburetor 8. In the following step 41, the switch 14c is connected to the signal line S1 side (FIG. 1). That is, based on the rotation speed of the combustion air supply device 6 detected in step 40, the rotation speed of the combustion air supply device 6 at the time of ignition is determined in step 41 according to the relationship shown in Table 1. decide. The rotation speeds in Table 1 are set so that the lower the carburetor temperature at the start of preheating, the lower the rotation speed of the combustion air supply device 6.

The preheating operation is started in step 42, and in step 43, it waits until the carburetor temperature reaches 220 ° C. In step 44, prepurge processing is performed, and the combustion air supply device 6 is turned on at the rotation speed determined in step 41. In step 44 above
After the rotation speed stable period of about 10 seconds has passed, the process proceeds to step 45, the igniter 28 is turned on, and at the same time, the electromagnetic pump control means 18 outputs a pulse signal (27 Hz) corresponding to strong combustion to the electromagnetic pump 3. At this time, the rotation speed of the combustion air supply device 6 is the same as the rotation speed at the time of pre-purge, and the rotation speed corresponding to the ejection of fuel corresponding to the strong combustion is 2450 rpm, whereas it is lower than that. . This is because the vaporized fuel oil vaporized in the vaporizer 8 is set to allow dew condensation until it reaches the flame port 13 through the mixing chamber 10. Step 46 is a routine for determining ignition. When ignited, the dew condensation in the mixing chamber 10 is rapidly improved as the temperature of the flame nozzle 13 rises. Therefore, in step 47, the mixing ratio after ignition detection is changed to stabilize combustion. That is,
When ignition is detected, the switch 14c is switched from the signal line S1 to the signal line S.
By switching to 2, the rotation speed of the combustion air control means 19 is changed to the rotation speed corresponding to the pulse signal output from the electromagnetic pump control means 18, so that combustion stability is maintained.

According to the configuration of the above-described embodiment, the flame opening temperature at the time of ignition is estimated from the carburetor temperature at the start of preheating, and the supply amount of combustion air and the amount of fuel ejected from the electromagnetic pump are adjusted in accordance with the flame opening temperature. Since the ratio is changed, lift combustion does not occur even during cold start when the combustion section is sufficiently cold, and yellow combustion occurs during hot start when the combustion section is already warm, such as during re-ignition. Without doing so, it is possible to obtain good ignition performance without fail. Further, since the carburetor cooling period of a fixed time is always provided at the time of hot start, the good correlation is maintained between the flame port temperature and the carburetor temperature at the start of preheating.

FIG. 5 shows a flow chart of another embodiment.
In the above embodiment, the timer was used to cool the warmed vaporizer 8 to a predetermined temperature, but in this embodiment, the vaporizer temperature is detected and the vaporizer 8 is cooled to a predetermined temperature or lower. It is a thing.

Explaining only the points different from FIG. 4, if it is determined in step 35 that the operation switch 23 is on, the following step 48
Then, the temperature of the vaporizer 8 is inspected, and the process flows in the direction of C until it becomes 100 ° C. or less. That is, the routine after step 40 is processed only when the temperature becomes 100 ° C. or lower.

According to the configuration of the above-described embodiment, the cooling of the carburetor 8 is ensured, and the correlation between the flame port temperature and the carburetor temperature at the start of preheating becomes more accurate.

In the above embodiment, as a mixing ratio control method for changing the mixing ratio between the vaporized combustion oil amount and the combustion air amount, the fuel injection amount is fixed and the carburetor temperature at the start of preheating is changed. Although the description has been given of the case where the rotation speed of the combustion air supply device 6 is changed, there is also a method of changing the fuel injection amount, conversely.
Further, the rotation speed of the combustion air supply device 6 was changed to change the supply amount of the combustion air, but the combustion air supply port 7
The diameter of may be changed in multiple steps with a damper or the like.

EFFECTS OF THE INVENTION As described above, the control device for a hot air heater according to the present invention detects the vaporization cylinder temperature at the time of ignition and changes the ratio of vaporized fuel oil to combustion air, so that the following effects are obtained. To be

(1) Normal ignition performance can be obtained even during cold start, where ignition is performed when the flame mouth is cold, or during hot start when ignition is performed when the flame mouth is warm.

(2) The carburetor temperature detector, which originally functions as a carburetor temperature control, can also be used for combustion compensation during ignition.

Further, in the present invention, since the vaporizing cylinder is cooled before ignition, the ratio of the combustion air and the vaporized fuel oil does not deteriorate even at the time of hot start, and more reliable ignition performance is obtained. can get.

[Brief description of drawings]

FIG. 1 is a block diagram of the present embodiment constituted by a burner using an opposing flame, FIG. 2 is a sectional view of the burner, FIG. 3 is a concrete circuit diagram of the main part, and FIG. 4 is the same. FIG. 5 is a flow chart for explaining the operation, FIG. 5 is a flow chart for explaining the operation of the other embodiment, FIG. 6 is a schematic structural view of a conventional oil heating equipment, and FIG. 7 is a control circuit diagram for the same. . 3 ... Electromagnetic pump, 6 ... Combustion air supply device, 8 ...
Vaporizer, 10 ... Mixing chamber, 12 ... Vaporizer temperature detector, 13 ...
… Flame tip, 17 …… Vaporizer temperature detection means, 20 …… Combustion control means.

Claims (2)

[Claims] 1. A vaporizer for heating and vaporizing fuel oil by a heater, vaporizer temperature detecting means for detecting the vaporizer temperature and controlling the vaporizer temperature to a predetermined temperature, vaporized fuel oil vaporized by the vaporizer and for combustion. A mixing chamber for mixing with air, and a flame opening for forming a flame, and detecting the vaporizer temperature at the time of starting the preheating operation of the vaporizer, vaporized fuel oil at the time of ignition and combustion air A control device for a hot air heater provided with a combustion control unit that changes a mixing ratio with the. 2. The control device for a warm air heater according to claim 1, further comprising a combustion control unit that operates the combustion air supply device to cool the carburetor temperature before starting the preheating operation.