JPH01281324A - Afterflow control method for heating apparatus - Google Patents

Abstract

PURPOSE:To prevent the adverse effect to the comfort even when the afterflow is protracted by controlling the motor speed so that the fan speed may be reduced gradually over a certain period of time from the stoppage of a burning apparatus to the complete stop of the fan. CONSTITUTION:When the power switch is turned off, the burning apparatus is immediately stopped. However, its motor 6 is turned off only after a delay time interval set by a memory control of CPU, i.e. the afterflow time. During the afterflow time, the speed of the motor 6, i.e. the speed of the fan 5, is gradually reduced by modulating the frequency of the applied voltage or controlling the phase of voltage wave shape in accordance with the control sequence predetermined like the set time. This way, while the temperature of hot air delivered out of the outlet 12 is maintained above a certain level, the burner and others in the cabinet 1 are cooled and stopped. Therefore, cold air is not delivered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an afterflow control method for a forced convection type heater.

[Prior Art] Fig. 2 is a front sectional view of a conventional heater, and Fig. 3 is a side sectional view of the same. In these figures, 1 is the outer box of the heater, 2 is a portable kerosene tank, 3 is a kerosene reservoir tank to which the portable kerosene tank 2 can be detachably attached, 4 is the bottom plate of the outer box 1, and 5 is a blower fan. , 6 is an electric motor that drives the blower fan 5, and is attached to the back of the outer box 1. 7 is a combustion burner, 8 is a flame detection frame that detects the state of the combustion flame of the combustion burner 7, 9 is a carburetor, and 10 is a nozzle operating valve, which operates the combustion burner 7, flame detection frame 8, carburetor 9, and nozzle. Valve 1
0 constitutes a combustor. 11 is an electromagnetic pump, 1
2 is an air outlet formed in the front part of the outer box 1, and 13 is the outer box 1.
A heat shield plate 14 for cutting off heat from electrical components (not shown) attached to the upper part of the interior is an overtemperature rise preventer.

Next, FIG. 4 is a control circuit block diagram of the above heating machine. In the figure, 30 is a power source, 31 is a power switch, and 32
33 is a power supply circuit, 33 is an input circuit connected to the power supply circuit 32, 34 is a CPU consisting of a microcomputer, 35 is an output circuit, 36 is a display system control circuit for display 39 for setting temperature, etc. and power supply display 40, 37 38 is a combustor control system circuit that controls the heater 9a of the carburetor 9 and the electromagnetic pump 11 by the output of the output circuit 35, and 38 is a control circuit for the electric a16 of the blower fan 5.

Next, the operation will be explained.

The kerosene supplied from the portable kerosene tank 2 enters the kerosene reservoir tank 3, and when the power switch 31 is turned on, the electromagnetic pump 11 is activated and is supplied to the vaporizer 9. Next, the vaporized kerosene gas is ejected to the combustion burner 7 by the operation of the nozzle operation valve 10, and at the same time, the combustion air around the nozzle is drawn in to form an air-fuel mixture, which forms a combustion flame by the ignition operation. The combustion flame is detected and controlled by a flame detection rod 8.

Next, by the rotation of the electric motor 6 attached to the back of the outer box 1 and the blower fan 5 connected to this electric motor 6, the high temperature gas generated from the combustion burner 7 is transferred to the intake port ( The hot air is mixed with indoor air sucked in from the air outlet (not shown), and is discharged as warm air from the outlet 12.

FIG. 5 is a sequence diagram showing the operation process of the combustor system and the blower system described in L, and this will be explained below in conjunction with FIG. 4.

When the power switch 31 shown in FIG. 4 is activated, the input circuit 3
A signal is received at 3. This input signal is processed by the CPU 34 and an operation command is sent to the output circuit 35. For example, when the power switch 31 is in the ON operation, the combustor system and the electric motor 6 operate almost simultaneously, as shown in FIG.
reach.

Next, when the power switch 31 is turned off, the electromagnetic pump 11 of the combustor system and the heater 9a of the carburetor 9 are immediately turned off, but the electric motor 6 continues to rotate for a certain period of time (afterflow). For example, the blower fan 5 turns OFF after 1 to 5 minutes have elapsed, and during this time, the blower fan 5 rotates at the same speed as during operation, and after the input signal to the electric motor 6 is cut off, there is a slight rotation due to inertia. However, everything comes to a halt almost simultaneously.

[Problem to be solved by the invention] As described above, in conventional heaters, even after the power switch is turned off, the electric motor does not stop immediately, but continues to rotate at a steady speed for a certain period of time to perform afterflow. It has become. This is to prevent the electrical components and the like provided in the upper part of the outer box 1 from becoming excessively hot due to the afterflow, and to protect these components. However, when the afterflow time is increased, since combustion has stopped, cold air is blown out from the outlet, which impairs comfort. For this reason, in the conventional case, it was necessary to make the afterflow time as short as possible, such as 30 seconds or 1 minute, and to make the structure more complicated, such as by duplicating the heat insulation structure such as the heat shield [13].

The present invention has been made in order to solve the above-mentioned problems, and it is possible to use a heat shield plate that does not impair comfort even if the afterflow time is lengthened, and that also serves as a heat insulator for electrical parts, etc. The purpose of the present invention is to obtain an afterflow control method for a heater that can be performed at low cost without complicating the insulation structure.

[Means for Solving the Problems] The afterflow control method for a heater according to the present invention is such that the rotation speed of the blower fan is controlled for a certain period of time after the combustion in the combustor is stopped until the rotation of the blower fan is stopped. This is characterized by controlling the rotational speed of the electric motor so that the rotational speed gradually decreases.

[Function] In the present invention, after combustion is stopped, afterflow is performed by gradually reducing the rotation speed of the blower fan and then stopping it, so that the temperature is maintained above a certain level during the first half of the afterflow time. In the second half, the blowing force suddenly attenuates, so cold air is not blown out. Further, this afterflow time allows sufficient cooling time for the combustor and the like to be ensured.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sequence diagram showing the operation process of the combustor system and blower system in the present invention. Although not particularly shown in the drawings, a control method for realizing such an operation process can be achieved by changing the set values of the CPU 34, output circuit 35, and motor control circuit 38 shown in FIG.

In FIG. 1, when the power switch 31 is turned on, the combustor, electric motor 6, and blower fan 5 start operating almost simultaneously, and the rotation speed of the blower fan 5 reaches a steady rotation of 800 to 11,000 rpm from zero.

After that, when the power switch 31 is turned OFF, the combustor immediately turns OFF and stops operation, but the electric motor 6 turns OFF after a delay of the time set by the memory control of the CPU 34, that is, the afterflow time. leading to. Moreover, during this after 70-hour period, the rotational speed of the electric motor 6, that is, the rotational speed of the blower fan 5, is gradually decreased by changing the frequency of the applied voltage or controlling the phase of the voltage waveform, etc., according to a preset control sequence similar to the set time. The temperature of the hot air blown out from the outlet 12 is maintained at a certain temperature or higher, and the combustor etc. in the outer box 1 are cooled, leading to a shutdown.

In this way, by controlling the rotation speed of the blower fan 5 to gradually decrease and then stop it during the afterflow time, even if the afterflow time is longer than the conventional one, the first half of the afterflow time is Warm air maintained above a certain temperature is blown out,
In the second half, the blowing force suddenly weakens, so cold air is not blown out and discomfort does not occur. At the same time, since the combustor etc. are sufficiently cooled during this afterflow time, there is no need to complicate the insulation structure such as the heat shield plate 13.

In addition, in the above embodiment, a method of attenuating and lowering the rotational speed of the motor during afterflow was shown by electrically changing the frequency and phase control of the power supply voltage, but other methods include adding a flywheel to the blower fan. It is also possible to adopt a physical method of providing.

[Effects of the Invention] As described above, according to the present invention, the afterflow after combustion stops is attenuated by gradually lowering the rotation speed of the blower fan, so the aircraft can be cooled without sacrificing comfort. This has the effect of making insulation structures such as heat shield plates cheaper.

[Brief explanation of the drawing]

Fig. 1 is a sequence diagram showing the operation process of the combustor system and blower system of the embodiment according to the present invention, Fig. 2 is a front sectional view of a conventional heater, Fig. 3 is a side sectional view of the same, and Fig. 4 is FIG. 5 is a control circuit block diagram of a conventional heating machine. FIG. 5 is a sequence diagram showing the operation process of a combustor system and a blower system of a conventional heating machine. 5...Blower fan 6...Electric motor 7...Combustion burner In the drawings, the same reference numerals indicate the same or corresponding parts. Agent Patent Attorney Muneharu SasakiFigure 1Figure 2Figure 3Figure 4

Claims (1)

[Scope of Claims] When performing afterflow after the combustion of the heater stops, the blower is configured such that the rotation speed of the blower fan of the heater gradually decreases for a certain period of time until the rotation of the blower fan of the heater stops. A method for controlling the afterflow of a heating machine, the method comprising controlling the rotational speed of a motor of a fan.