JPH0240070A - Preheating controller for vaporizing combustion chamber - Google Patents

Abstract

PURPOSE:To make ease of correspondence to the promotion of high capacity by energizing a half-wave rated current to a heating element in succession when a temperature signal is not reached to a first temperature judged value, and when it exceeds the first temperature judged value but is not reached to a second temperature judged value, performing this current-energization to the heating element continuously. CONSTITUTION:Both first and second temperature judged values T1, T2 are preset to a control part 7. A succession energizing means 8 energizes each of tungsten heating elements 3a, 3b continuously when a temperature signal Ts out of a temperature detecting sensor 6 is Ts<T1. With this current-energization, temperature in a carburetor 1 is quickly raised up, while a rush current comes to 1/2 or so as compared with the case of full-wave energization. In addition, a continuous energizing means 9 energizes these tungsten heating elements 3a, 3b continuously when it is T2>Ts>T1. In this case, as for the rush current at the time of continuous energization starting, resistance value in a ceramic heater 5 is nearly redoubled as compared with time of room temperature, so that it is the same degree as the rush current at the time of operation of the successive energizing means 8. Accordingly, since the rush current is sharply reducible, it can correspond even to the promotion of high capacity in an easy manner.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a vaporization type combustor that gasifies and burns fuel using the heat generated by a ceramic heater, and in particular significantly reduces the rush current that flows during preheating of the combustor. The present invention relates to a preheating control device that can easily realize large capacity.

(Prior Art) In recent years, the capacity of water heaters in particular has been significantly increased in order to simultaneously supply hot water to multiple locations.

This type of water heater includes the one shown in Fig. 5, and when the operation is started, the preheating operation starts, and one of the vaporizers 5
The ceramic heater 52a built in the ceramic heater 52a starts to be energized, and after an appropriate short period of time, the other vaporizer 51b is turned on.
The ceramic heater 52b is also energized. The temperature of each vaporizer 151a, 51b rises due to the energization, and the temperature signals from the temperature detection sensors 53a, 53b that detect this temperature reach a preset value corresponding to, for example, 300°C once a month. At the same time as completing preheating,
Thereafter, the temperature of the vaporizers 51a and 51b is controlled to a target temperature (for example, 300°C) by phase control, on/off control, etc.
) will be maintained.

Then, in response to a combustion request made immediately after appropriately detecting water entering the water heater, the solenoid bodies 56a, 56b, etc., which operate the valve levers for opening and closing the electromagnetic pumps 54a, 54b and the jet ports 55a, 55b, operate. Fuel is in the carburetor 51
a, 51b, it is gasified and becomes vaporized scum, and the ejection port 55
a, 55b to the lipanas 57a, 57b, where they are combusted.

During the preheating operation, each ceramic heater 52a,
The reason why energization to 52b is not started at the same time is as explained below.

In other words, ceramic heaters are generally formed by embedding a heating element such as tungsten in a heat-resistant insulating material such as alumina, and have the characteristic that the resistance value increases as the temperature rises, as expressed by the following equation. There is.

Rt2 = Rtl (+ + C(Tp -20)
)Tp: Ceramic heater temperature (0C) Rt2:
Resistance value of the ceramic heater at Tp CC) Rtl: Resistance value of the ceramic heater at the reference temperature (here, 20°C) C: Constant, e.g. 0.003') According to the above equation, if the ceramic heater at the vaporizer temperature of 300°C If the temperature of reaches approximately 600℃,
The resistance value at room temperature is 1/2 to 1/3 of that at the high temperature.

However, if the ceramic heaters 52a and 52b are energized at the same time, a large inrush current will flow immediately after the ceramic heaters 52a and 52b are energized due to their low resistance values, making it easy to cause various problems such as blinking of the lamp.

(Problem to be Solved by the Invention) However, the above-mentioned measures were not sufficient to reduce the rush current. To explain this using FIG. 6, a current Ia flows when the ceramic heater 52a is energized (point C), and thereafter the current decreases due to heat generation and temperature rise. After a short period of time, when the ceramic heater 52b is energized (at two points), the current in the ceramic heater 52a is Ia';
Since the inrush current Ia to b is added, the overall maximum I
A current of b (=I a + I a') flows.

This current 1b is considerably large compared to other electric appliances, and can easily cause the above-mentioned problems depending on the indoor wiring, the type of contract with the electric power company, etc. In addition, the occurrence of this problem has been a significant hindrance to increasing the wattage of ceramic heaters, that is, increasing the capacity of vaporizing combustors such as water heaters.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a preheating control device for a vaporizing combustor that can significantly reduce inrush current and can easily accommodate increased capacity. .

(Means for Solving the Problems) In order to achieve the above-mentioned object, a preheating control device for a vaporization type combustor of the present invention is provided with a ceramic heater having a plurality of tungsten heating elements embedded therein. A vaporizer that turns fuel into scum at an elevated temperature due to heat generation, and a control unit that controls energization to each of the tungsten heating elements based on a temperature signal from a temperature detection sensor provided in the vaporizer. Further, the control unit has first and second temperature determination values for determining a temperature increase state during preheating of the vaporizer set in advance, and when the temperature signal does not reach the first temperature determination value, sequential energization means for sequentially applying half-wave current to each tungsten heating element; continuous energization means for energizing.

(Function) With the above-described configuration, when the operation start operation is performed when the vaporizer is at a relatively low temperature, the energizing means is first operated in sequence to sequentially energize each tungsten heating element for half a wave, and The temperature of the vaporizer increases considerably by energization,
When the temperature signal from the temperature detection sensor that detects this temperature exceeds the first temperature judgment value, the continuous energization means operates, so the inrush current can be kept at a significantly low value throughout the preheating operation of the vaporizer. Can be done.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, 1 is a vaporizer that converts fuel supplied from an electromagnetic pump 2 into scum, and is formed by embedding a plurality of tungsten heating elements 3a and 3b in a heat-resistant insulating material 4, each having an independent current conduction path. A ceramic heater 5 is fitted therein, and a temperature detection sensor 6 for detecting the temperature of the vaporizer 1 is provided on the outer periphery. 7 is, for example, 150°C and 30°C, respectively.
A control unit in which a first temperature determination value T1 and a second temperature determination value T2 as values corresponding to 0° C. are set in advance,
Furthermore, the control unit 7 receives the temperature signal Ts(
Actually, it is a value obtained by converting the input terminal as described later. ) is Ts<TI, each tungsten heating element 3a,
sequential energization means 8 that sequentially energizes T2 in half waves at a time;
>Ts≧T1, continuous energization means 9 continuously energizes each tungsten heating element 3a, 3b, and in this embodiment, for example, T2 is also used as a value corresponding to the target temperature, and the target temperature is Each tungsten heating element 3a to maintain
, 3b includes a control energization means 10 for controlling the amount of energization by phase control.

In addition, 11 is a nozzle pipe formed with a spout 12 formed at one end, and communicates with the vaporizer 1 via a communication port 13. Reference numeral 14 represents a valve lever for opening and closing the spout 12, which is operated by a solenoid body 15. 16 is an oil feed pipe, 17 is a return pipe, 18 is a burner,
19 is a spark plug, and 20 is an oil storage tank.

FIG. 2 is a circuit diagram of the embodiment shown in FIG. In the figure,
The microcomputer MC reads a ROM that stores various control data and control programs such as a first temperature judgment value T1 and a second temperature judgment value T2, a RAM that stores temperature signals Ts, etc., and a control program stored in the ROM. It is composed of a CPU, etc. that executes various processes. Also, TRA is a transformer (
Secondary side), SW is the operation switch, TRI to TR5 are transistors, 01 to C5 are capacitors, D1 to D4 are diodes, PTI and PT2 are phototriacs, R1
-R18 is a resistor, ZD is a Zener diode, A and B
is the connection terminal to the commercial power supply.

Note that PO-P7 in the microcomputer MC is a boat for human power or output.

The operation of the above-described configuration will be further explained below with reference to FIGS. 3 and 4.

The secondary power supply of the transformer TRA is rectified and smoothed by the diode D1, the diode D2, and the capacitor C1, and the Hase voltage is applied to the transistor TRI via the resistor R1, so the transistor TR1 is turned on, and a DC voltage of 10 VCC is applied to the port P6. to use human power. In addition, the DC voltage full-wave rectified by diode D3 and diode D4 is baud)
P7 is manned. temperature detection sensor 6 to P5
The voltage divided by and resistor R9 is manually applied, and the voltage is converted into a temperature signal Ts and stored in the RAM.

When the operation switch SW is closed, that is, the operation of the combustor is started, and a signal is input to PI, the preheating operation of the carburetor 1 is started, and a control voltage is output from P2 to turn on the transistor TR2. At the same time transistor TR3
At the same time as turning on Ts, read Ts (S-1),
and T1 (S-2).

When Ts<TI, the energizing means 8 operates in sequence, and the baud)P
It is investigated whether the voltage input to 7 is zero (S
-3) If it is not zero, return to S-1.

Note that when Ts≧T1, such as when the operation switch is closed immediately after the operation of the combustor is stopped, the process moves to S-7 without executing S-3 and subsequent steps.

In S-3, if the voltage is zero, the energization status to one of the tungsten heating elements 3a is investigated (S-4).

At the beginning of preheating, the tungsten heating element 3a is not energized, but a control voltage is output from the boat P3 to turn on the transistor TR4, and the light receiving side of the phototriac PTI is made conductive, thereby making the retriac T1 conductive. Commercial power is supplied to the tungsten heating element 3a (
S-5).

When the voltage at S-3 becomes zero again, the output of the control voltage from baud) P3 is stopped and the energization to the tungsten heating element 3a is stopped, and at the same time, the control voltage is output from baud) P4 to turn on the transistor TR5. Commercial power is supplied to the other tungsten heating element 3b (S-6) in the same manner as the energization to the tungsten heating element 3a.

That is, the energizing means 8 sequentially turns each tungsten heating element 3 on, especially at low temperatures when the ceramic heater 5 has high heat generation efficiency.
Half waves are applied alternately to a s 3 b,
As a result, the temperature of the vaporizer 1 is rapidly raised, and the rush current is about 172 times higher than that in the case of full-wave energization.

In S-2, the temperature of the ceramic heater 5 is, for example, 3.
When the temperature rises to 00°C and Ts reaches T1 (point A)
Then, the continuous energization means 9 operates to check whether preheating is completed, that is, whether Ts≧T2 (S-7).

When T2>Ts≧T1, each tungsten heating element 3a,
Investigate whether continuous energization is being performed to 3b (S-8)
.

When the continuous energization is not performed, a control voltage is continuously output from Baud 1-P3 and Baud) P4, and the tungsten heating elements 3a and 3b are continuously energized to promote the temperature rise of the vaporizer 1. At the same time, the extension of preheating time is suppressed.

Regarding the inrush current at the start of continuous energization, since the resistance value of the ceramic heater 5 is almost double that at room temperature, the inrush current is comparable to the inrush current at the time of operation of the sequential energization means 8.

When the continuous energization means 9 continues to operate and becomes Ts≧T2 (
Point) Preheating is completed, and at the same time, the presence or absence of a combustion request is investigated (S-10), and if there is no combustion request, the energization to the tungsten heating elements 3a, 3b is stopped (S-11).

After the energization is stopped, the control energization means 10 operates, and the temperature of the vaporizer 1 is maintained at approximately the target temperature until the operation switch SW is opened.

When a combustion request is issued after preheating is completed, the electromagnetic pump 2 is driven and the fuel in the oil storage tank 20 is pumped to the vaporizer 1.

The fuel that has flowed into the carburetor 1 is gasified into vaporized gas, which reaches the nozzle pipe 11 through the communication port 13, and then flows through the burner 18 through the spout 12 opened by the action of the solenoid body 15.
It is ignited and burned by the discharge of the spark plug 19.

Note that the preheating control device having the above-described configuration is also useful for the vaporization type combustor having a plurality of vaporizers as described in the conventional example.

(Effects of the Invention) As described above, according to the preheating control device for a vaporizing combustor of the present invention,
Since the inrush current that flows during preheating of a vaporizer equipped with a ceramic heater can be significantly reduced, it does not have a negative effect on other electrical appliances, making it possible to construct a combustor that is easy to handle, and can easily accommodate increased capacity. It has many effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the preheating control device for a vaporizing combustor according to the present invention, FIG. 2 is a circuit diagram of the embodiment shown in FIG. 1, and FIG.
The figure is a flowchart explaining the operation of the preheating control device for a vaporizer combustor of the present invention, FIG. 4 is a diagram showing the progress of temperature rise of the vaporizer in FIG. 1, and FIG. 5 is the structure of a conventional vaporizer combustor. FIG. 6 is a diagram illustrating the current consumption of the vaporizer in FIG. 5. Reference Signs List 1 vaporizer, 7 control unit 8 sequential energization means, 9 continuous energization means.

Claims (1)

[Claims] A vaporizer is equipped with a ceramic heater in which a plurality of tungsten heating elements are embedded, and gasifies the supplied fuel by raising the temperature due to the heat generated by the ceramic heater. a control section that controls energization to each of the tungsten heating elements based on a temperature signal, and the control section has first and second temperature determination values for determining a temperature increase state during preheating of the vaporizer in advance. sequential energization means for sequentially applying half-wave current to each of the tungsten heating elements when the temperature signal is set and the temperature signal does not reach the first temperature determination value, and when the temperature signal exceeds the first temperature determination value and continuous energization means that continuously energizes each of the tungsten heating elements when the second temperature determination value has not been reached;
A preheating control device for a vaporizing combustor.