JPS60181512A - Combustion safety device - Google Patents

Abstract

PURPOSE:To contrive to establish the set temperature at the temperature control within a vinyl plastic hothouse by a constitution wherein, when the firing realizes after the predetermined number of ignition trials, the normal running is restored and the combustion is continued. CONSTITUTION:In stead that the instant safety stop action is taken when firing fails to realize, it is so constituted that the safety stop action is taken when firing fails even after the execution of predetermined number of ignition trials. Concretely, a multiple ignition circuit 25 consists of comparators CMP1-CMP3 are one-shot multivibrator circuits OS1-OS3 connected to the respective output terminals of CMP1-CMP3. The respective comparators CMP1-CMP3 compare the charging voltage VIN of a capacitor C1 with the pre-set reference voltages V1-V3. When VIN exceeds the respective voltage V1-V3 as charging proceeds, transistors Q1-Q3 are turned ON pulsewise through the one-shot multivibrator circuits OS1-OS3. The pulse is waveform-shaped at an ignition reset circuit 22 and then inputted to the 2 terminal of IC20 in order to reset IC20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion safety device, and is particularly suitable for controlling the temperature of greenhouses for agricultural greenhouse cultivation. It concerns safety equipment.

□ Show the overall system diagram. 1 is a vinyl house,
2 is a cultivated vegetable. 3 is a combustor. This combustor 3 includes a combustion chamber 4, a 7-hole 5 for air circulation, and 6 air holes.
, a burner 7, and a combustion device 8 made of pulp or the like for adjusting the combustion amount of the burner. Reference numeral 9 denotes a room thermostat having a temperature setting device for detecting the temperature inside the greenhouse and setting the temperature inside the greenhouse.

10 is a protect relay, which safely controls the combustion device 8 in order to control the temperature inside the greenhouse to the set temperature set by the room thermometer 9.

Reference numeral 11 denotes an oil tank that stores oil as fuel. Usually, this oil tank is installed outside the greenhouse 1. The oil in the oil tank 11 is supplied to the combustion device 8 through the fuel pipe 13 by the pump 12, and is combusted in the burner 7. Generally, in combustion control of greenhouses, heavy oil, which is cheap in unit price, is used as the oil, so the viscosity of this heavy oil increases during winter operation, making it difficult to supply fuel smoothly. As a countermeasure for this, a heater is placed in the middle of the fuel pipe and heated to a predetermined temperature to lower the viscosity of the heavy oil, and a heater is similarly placed at the nozzle at the tip of the fuel supply pipe of burner 7. However, a device has been devised so that the fuel can be injected smoothly by heating this heater to a predetermined temperature.

Even with such contrivances, there are times when the burner cannot be ignited. This is because the viscosity of the oil has not been lowered to the desired level, so the oil is injected in a solid state, making it difficult to ignite.Also, air gets mixed into the fuel pipe for some reason, making it difficult to ignite. It is thought that the reason for this is that The occurrence of this phenomenon in which the burner cannot ignite is a very serious problem when controlling the temperature of vinyl gas.

In other words, in general, temperature control for greenhouses is based on combustion.
The aim is to achieve the set temperature by running this in 0N10FF mode, but if it does not ignite, combustion will be stopped, which will cause the room temperature to drop and cause irreversible damage to the vegetables being grown. Become.

Conventional technology to deal with this problem is that when a protect relay detects non-ignition using the output of a flame sensor,
A configuration is adopted in which a display means is driven to inform farmers who grow vegetables of this fact. However, due to the nature of greenhouse cultivation of vegetables, temperature control in greenhouses must be carried out day and night, so displaying information using display means alone is extremely insufficient, and practical problems remain.

The present invention has been made to solve this problem, and even if ignition is not achieved, the combustion is not immediately stopped, but the ignition is repeated or re-ignited, and a predetermined number of ignition trials are carried out. It is an object of the present invention to provide a combustion safety system configured to determine that an abnormality occurs only when ignition is not achieved even after the combustion has occurred, and to stop combustion and drive a display means. That is, when ignition is achieved within a predetermined number of ignition trials, normal operation is resumed and combustion continues.

Hereinafter, the present invention will be described in detail based on examples. FIG. 2 shows an example of the present invention. 20 is a dedicated IC having a fail-safe function developed for a combustion safety device, and executes a combustion sequence based on data input to this IC 20. The ■ terminal of IC20 is a start/stop input. The room thermometer 9 shown in FIG. 1 is connected to this terminal (2), and when the room temperature of the greenhouse 1 is out of a predetermined range, a start or stop signal is input to start or stop combustion. ■ of IC20
The terminal is a reset input. When a reset signal is input to this terminal (2), the IC 20 is set to a reset state, which will be described later. The reset signal is generated by a power supply reset circuit 21 that sends out a reset signal in synchronization with the combustion request/stop signal of the room thermometer 9, and a repeated ignition reset circuit 22 that constitutes the repeated ignition system that is the gist of the present invention. There is. The ■ terminal of IC20 is an igniter drive output. When the ■ terminal is at the HI ratio output, turning on the transistor Q4 turns on the relay 1, which drives the igniter, which is not shown in this figure, and executes the ignition trial. The ■ terminal of IC20 is the fuel supply output. When this ■ terminal outputs a HI ratio, transistor Q5
By turning on the relay 2, a fuel valve (not shown in this figure) is opened, and the pump 12 is driven to supply fuel to the burner 7. The ■ terminal of IC20 is the SSH drive output. When the ■ terminal outputs a HI ratio, 5SH23 is driven by turning on the transistor Q6. The SSH 23 is a thermal safety switch, and when it is energized for a predetermined period of time, the normally closed contact 24 linked to it opens due to the action of a bimetal, etc., and the combustion system enters a safe shutdown, making it impossible for the burner 7 to ignite. A warning will be issued to let people know that this is the case. Furthermore, when the ■ terminal is in a HI ratio output, the capacitor C1 is charged via the diode D1. Charge voltage VIN of this capacitor C1
When the level of the ignition circuit 25, which will be described later, is driven and the ignition trial for re-ignition is repeated, the level becomes K.

The ■ terminal of IC20 is the flame sensor input. When the flame sensor 26 connected to this terminal detects a flame, its resistance value changes, and this is used to input that a flame has been established. The ■ terminal of IC20 is the ignition detection output. When the establishment of a flame is inputted through the terminal (2), the terminal sends out a HI ratio output and turns on the transistor Q7, thereby discharging the capacitor C1 via the diode D2.

The ■ terminal of the IC 20 is a ground terminal, and the ■ terminal is a power supply terminal.

FIG. 3 shows an embodiment of the repetitive ignition circuit 25 shown in FIG.
It consists of comparators CMPI-CMP3 and one-shot circuits O81-083 connected to their output terminals. Each comparator CMPI to CMP3 compares the charging voltage vN of the capacitor C1 with a reference voltage v1 to v3 set in advance, and when VIN becomes higher than each reference voltage v1 to v3 as the charging progresses, one The transistors Q1 to Q3 are turned on in a pulsed manner via shot circuits 081 to O83.

When one of the transistors turns on, the photocube = trt (Figure 2) connected to the collector of that transistor is driven, and the transistor Q8 turns on in a pulsed manner.
This pulse is waveform-shaped by the ignition reset circuit 22, and is input as a reset pulse to the ■ terminal of the IC 20 to reset the IC 20.

Next, the operation of the present invention will be explained. vinyl house 1
When the room temperature falls below the set temperature determined by the room thermostat 9, the room thermostat 9 sends a start signal to the IC20 terminal (3) to start combustion. At the same time, a reset signal is inputted to the (2) terminal of the IC 20 via the power supply reset circuit 21, and the IC 20 is reset. When the IC 20 is reset, all of the output terminals ■, ■, ■t of the IC 20 are reset to the LO ratio output. Immediately thereafter, the ■ terminal becomes the HI ratio output, and 1 is turned on in the relay, thereby driving the igniter provided in the combustion device R8. ■After the terminal reaches the HI ratio output, and then after a predetermined period of light, ■When the terminal becomes the HI ratio output, relay 2 turns ON, which opens the fuel valve installed in the combustion device 8 and drives the pump 12. Then, fuel is supplied to the burner 7. If the combustion system is normal, a flame will be established here, and the IC 20 will detect the flame at the ■ terminal due to the change in the state of the flame sensor 26, and will stop driving the igniter by outputting the LO ratio to the ■ terminal, thereby establishing a normal combustion state. It is something that goes into. Note that the ■ terminal switches the HI ratio output at the same time as flame detection.

■When the terminal starts supplying fuel (after reaching the HI ratio output, within a predetermined time ■When there is no flame detection input to the terminal, the IC
20 outputs the LO ratio output from the ■ and ■ terminals to cancel the ignition trial, and switches the ■ terminal to the HI ratio output to start charging the capacitor C1 and start energizing the 5SH23. In order to simplify the explanation here, the multi-ignition circuit 25 shown in FIG.
, 3, and the reference voltage of each comparator is set to V+ < Vz < Vs. As shown in FIG. 4, when the charge voltage VIN of the capacitor CI reaches 1, the transistor Q1 is turned on in a pulsed manner, and a reset pulse whose waveform is shaped by the ignition reset circuit 22 is passed through the photocoupler U1 to the IC20.
The IC 20 is reset by inputting it to the ■ terminal. IC2
When 0 is reset, the terminal (3) switches the LO ratio output, so the power supply to the 5SH23 is stopped, and the thermally responsive part of the 5SH23 is cooled, so the normally closed contact 24 rarely opens.

Further, the (2) terminal has the LO ratio output, but since the terminal since no flame is detected maintains the LO ratio output, the charge voltage VIN is held at the VlO value.

When a reset pulse is input to the terminal (■) of the IC 20, the above-described ignition trial will be repeated again. If ignition is achieved here, the ■ terminal becomes a HI output, and the charge voltage VIN is discharged to Ov through the transistor Q7, which is turned on, and everything returns to a normal state and enters a normal combustion state. Here, when it is confirmed again by the flame sensor 26 that the ignition cannot be ignited, the IC 20 once again changes the terminals ■ and ■ to LO output, cancels the ignition trial, and
Switch the terminal to HI output and charge the capacitor C1. As shown in FIG. 4, this charge voltage VIN is
When snow arrives, the IC20 will be reset and the ignition trial will be repeated again. In this embodiment, the ignition trial is repeated three times, but if the ignition fails even after these three times, the charge voltage VIN becomes VIN)Vs, and the reset pulse is not repeatedly output from the ignition circuit 25. do not have.

From now on, the ■ terminal of IC20 will maintain the HI output state, so SSH23 will continue to be energized, and after a predetermined time determined by the thermal response part of SSH23 has passed, the normally closed contact 24 will open, and for the first time, the farmer who is the cultivator will It will be displayed to people that it is impossible to ignite, and maintenance will be required.

Further, the repeated ignition circuit 25 that executes this re-ignition trial has a fail-safe function that is naturally required of a combustion device. That is, multi-ignition circuit 2
If component No. 5 fails, the reset pulse will not be generated. Since the IC 20 will not be reset from now on, the ignition trial will not be repeated and the SSH 23 will continue to be energized, so the system will enter a safety shutdown.

In this manner, the present invention does not immediately enter a safety shutdown when ignition cannot be achieved in a combustion safety device, but performs a predetermined number of ignition trials, and when ignition still cannot be achieved, enters a safety shutdown. By configuring this structure, it is possible to improve the practicality of a combustion system in which non-ignition is likely to occur, and it has a great effect.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional view showing a temperature control system for a normal greenhouse, Fig. 2 is a circuit diagram of the main part of a combustion safety device according to an embodiment of the present invention, and Fig. 3 is the device shown in Fig. 2. FIG. 4 is a circuit diagram of the repetitive ignition circuit used in the ignition circuit, and FIG. 4 is a diagram of its operating waveforms. 3... Combustor, 4... Combustion chamber, 5... Fan, 7
...Nox, 8...Combustion device, 9...Room thermo, 10...Pre-protection relay, 11...Oil tank, 12...Pump, 20...ICSCMPI
~CMP 3...Konokureta, 081~083・
...One-shot circuit. 'Patent applicant: Yamatake Newel Co., Ltd. Figure 3 Figure 4 f

Claims (1)

[Claims] Output means that outputs an output signal when the flame detection means does not detect flame within a predetermined time after starting the ignition operation according to a predetermined combustion sequence, and stops the output signal when flame is detected. a safety switch connected to the output means and configured to safely stop combustion when the output signal does not stop within a predetermined time; a charge storage means for accumulating and holding charge; a repeating ignition circuit having at least two set values and sending out a signal instructing execution of an ignition trial each time the charge in the charge storage means reaches these set values; A combustion safety device comprising a reset means for releasing the charge stored in the charge storage means when the flame detection means detects a flame.