JPH02306019A - Safety device for hot air type heater - Google Patents

Abstract

PURPOSE:To reliably prevent the generation of back fire from a burner and leakage of gas through a combustion chamber by a method wherein when a detecting value of torque of a burner motor exceeds upper limit set torque, a speed decrease signal is outputted, and when it is below a lower limit set torque, a speed increase signal is outputted, and when the speed decrease signal and the speed increases signal are outputted, combustion operation is stopped. CONSTITUTION:When a feed amount is brought into a reduced state by means of back wind through, for example, a chimney, a burner motor load is increased, and torque exceeds an upper limit set value. As a result, an abnormality detecting means 32 detects that a voltage applied on a burner motor is higher than a voltage responding to upper limit set torque to output a speed decrease signal, and a fan motor 11 is decelerated by a speed varying means 33. Since the motor speed of a convection fan 3 is reduced to a lower limit set value, when simultaneously with stabilization of combustion, torque is decreased to a value lower than an upper limit set value, combustion operation is continued. When the torque exceeds upper limit set torque, an abnormality stop means 34 sends a stop output, and a hot air heater stops combustion operation.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention prevents abnormal operation of a hot air heater that has a rotary burner that vaporizes liquid fuel such as white kerosene, mixes it with air, and then burns it. The present invention relates to the configuration of a security device to be obtained.

(Prior art) A rotary burner in which an oil pump, a fan, and a burner motor are directly connected coaxially is connected to a combustion chamber of a heat exchanger, and the combustion gas generated by the rotary burner, that is, vaporized fuel and air are mixed. A device that heats air using combustion heat obtained when combustible gas is combusted in the combustion chamber is called a hot air heater, and is widely used for commercial and home use.

Unlike those that use natural convection of air to mix combustion residue into the indoor air, this type of hot air heater uses a convection fan to forcibly send air around the heat exchanger. Heat exchange between combustion gas and air is performed through the heat transfer wall of the convection fan, and the convection fan simultaneously supplies air to the rotary burner and the combustion chamber.

By the way, it is undesirable that stable combustion cannot be achieved over a wide range of temperatures due to the effect of changes in the amount of air supplied due to fluctuations in room temperature, so recent hot air heaters are not suitable for practical use. As disclosed in Japanese Patent Application No. 61-161528, the motor of the rotary burner is formed by a motor whose torque increases or decreases in response to the level of applied voltage or current, and the rotary burner is used when the room temperature is low and the specific gravity of the air is high. If the room temperature is high and the specific gravity of the air is low, then the torque should be increased, and conversely, if the temperature is high and the specific gravity of the air is low, the torque should be decreased. In this method, the rotation speed of the convection fan is lowered to reduce the amount of air supplied to the rotary burner, and conversely, when the torque is small, the rotation speed of the convection fan is increased to increase the amount of air supplied to the rotary burner. things are provided.

(Problems to be Solved by the Invention) The hot air heater having the above-described structure is able to secure an appropriate amount of air supply without being affected by changes in air temperature, and is always efficient and stable over a wide temperature range. However, when this warm air heater is called a CF type and is used in a way that takes in indoor air and discharges the exhaust gas after combustion to the outside through a chimney, it has the following advantages: There are some problems.

In other words, if the air filter is left unchecked, torque control and air supply control will be affected by external factors such as changes in the draft head of the chimney, air blowing from the chimney, and increases in indoor negative pressure due to ventilation fan operation. If proper follow-up operation is not possible, a packfire phenomenon, gas leakage, lift failure, CO generation, etc. may occur, and safety problems remain.

The present invention has been developed by focusing on such problems, and it is possible to eliminate danger by accurately detecting abnormal phenomena based on the relationship between the burner motor torque limit value and the convection fan motor speed limit value. The purpose of the present invention is to provide a device that increases safety by stopping combustion operation before a dangerous situation occurs.

(Means for Solving the Problems) As is clear from the drawings showing the embodiments, the present invention includes a heat exchanger (1) incorporating a combustion chamber (7) connected to an exhaust passage (24) such as a chimney; An oil pump (8) and a burner fan (9) are coupled to a variable torque type burner motor aω, and the vaporized fuel spouted by the oil pump (8) and the air sucked from the air suction port by the burner fan (9) are combined. a rotary burner (2) that generates a mixture of combustion gas and supplies it to the combustion chamber (7); and a variable speed fan that changes the rotation speed according to the torque level of the burner motor αC. Connected to the motor αυ, the air suction port (b)
In a hot air heater equipped with a convection fan (3) that promotes air suction at the air suction port by supplying air to the air intake port, the torque of the burner motor α is detected and the detected value is set as the upper limit. The abnormality detection means (32) outputs a deceleration signal when the torque and the lower limit set torque are larger than the upper limit set torque, and outputs a speed increase signal when the lower limit set torque is smaller than the lower limit set torque; ) A speed changing means (33) that receives a signal from the fan motor 0υ and applies a deceleration output to decrease the speed using a deceleration signal and an increasing output to increase the speed using a speed increase signal.
and a stop output that stops the combustion operation when the fan motor 0υ has reached the lower limit set speed and the deceleration signal is output, and when the fan motor 0υ has reached the upper limit set speed and the speed increase signal is output. Abnormal stop means (34)
), the security device is configured by:

(Function) By installing the above-mentioned safety device, if the indoor pressure becomes negative as a result of operating a large ventilation fan, or if there is a backflow from the chimney, etc., it will be covered within the air volume adjustment range of the convection fan. If it becomes impossible, the abnormal stop means (3)
4) is activated and stops the combustion operation, so safety is high.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a schematic structural diagram of a hot air heater according to an example of the present invention, in which an inlet (5) is opened at the lower front, and an outlet (6) is opened at the upper front and the middle of the front. Inside the casing (4), from above, there is a heat exchanger (1), a rotary burner (hereinafter referred to as burner) (2), and a convection fan (3).
The burner (2) has a burner head (11
is passed through the bottom wall of heat exchanger +11, and the heat exchanger (
1) is placed facing the combustion chamber (7) inside.

The hot air heater described above operates by energizing the convection fan (3) and operating the burner (2) for combustion.
The combustion gas generated in the combustion chamber (7) burns at the flame port, heats the peripheral wall of the heat exchanger (1), and then passes through the exhaust passage (24).
), while the convection fan (3
), a portion of the indoor air led into the casing (4) from the suction port (5) is sent to the air suction port Q2+ of the burner (2) to promote suction, and most of the air is heated. After being heated while flowing along the outer heat transfer wall of the exchanger (1) and becoming hot air, the air flows through the two outlets (6), (
6), the air is sent into the room, thus heating the room.

The burner (2) has the structure shown in FIG. 3, and has a combustion section, a vaporization section, a fan section, and a pump section arranged in this order from top to bottom.

The combustion section has a burner head αe1 having a flame port (11) and a spark plug (2I) provided at a position in contact with the flame formed on the burner head frame.

The vaporization section includes a vaporizer 0ω, a vaporization heater 07), and a diffusion vane α.
Has a frame.

The fan part is a fan (
9), and the fan (9) is axially connected to one shaft of the burner motor αω.

The pump part has a fuel filler port (2) that sends liquid fuel such as white kerosene.
2) and a drain plug (23), and an inner cylinder having an oil pump (8) with a nozzle α hot water opening downward at the bottom and a pump chamber (+41) at the top. The shaft of the oil pump (3) is connected to the other shaft of the burner motor αΦ.

Ru.

The burner (2) having such a structure is called a synchro gasification burner that has an oil pump (8) and a fan (9) coaxially integrated.First, in the fuel system, fuel is supplied from an oil tank or the like through an oil level regulator or the like. is introduced into the pump chamber Q4), and the oil level is maintained at a certain level.

The fuel, which is pressurized by the oil pump (8) as the burner motor (11) rotates, is quantified by the nozzle a1, passes through the oil passage provided in the shaft of the burner motor (11), reaches the diffusion vane α, and is centrifuged here. Radiation scatters due to the action.

The temperature of the scattered oil particles is raised by the vaporization heater αη (2
60-290°C) impinges on the vaporizer (2) wall and vaporizes.

On the other hand, in the combustion air system, air flows from the damper (21) by the rotation of the fan (9), is pressurized, and flows into the carburetor αω.

In this case, approximately 70% is supplied as primary air and approximately 30% as secondary air.

The primary air introduced into the vaporizer aQ is mixed with the fuel atomized and vaporized by the diffusion vane α, while passing through the flame port a9.
It is emitted from the slit, ignited by the spark plug (2 m), and combustion continues.

Combustion operation control of the hot air heater having the above structure will be explained with reference to FIGS. 1 to 4.

The burner motor OI, which is the drive source of the burner (2), is a variable torque motor, such as a DC motor or a capacitor motor, whose torque increases or decreases depending on the level of applied voltage. The fan motor αD, which is the drive source of The burner motor (1
1 performs constant speed operation control, and fan motor 0υ performs variable operation control.

By the way, it is possible to change the torque and speed of a DC motor or a capacitor motor by changing the applied voltage.

Currently, with feedbank control, which detects the motor speed and keeps the motor speed constant, when the load applied to the motor increases, the voltage applied to the motor increases in order to maintain it at a predetermined value so that the speed does not drop, and conversely the load increases. When the voltage decreases, the applied voltage decreases.

That is, the voltage applied to the motor changes depending on the load, and it is therefore possible to know the magnitude of the load by detecting the voltage applied to the motor.

The control circuit shown in Fig. 1 controls the burner motor 0ω to be maintained at a constant rotation speed by the feed bank profit circuit (25) regardless of changes in the load (air amount), and controls the fan motor 0υ by the speed control circuit (26). ) is a circuit configuration that performs control to change the speed to an upper limit setting speed of high rotation, a lower limit setting speed of low rotation, and a stepless arbitrary speed between them.

The feedback control circuit (25) controls the burner motor QO
) at a predetermined rotation speed, and a speed detection section (28) that detects the rotation speed of the burner motor aω. The '4J11 circuit (27) on the motor speed side is configured to emit a feedbank-controlled voltage output so that the detected rotational speed matches a predetermined rotational speed.

In the motor speed control circuit (27), an upper limit value and a lower limit value of torque are set to define a torque adjustment range, and the motor speed control circuit (27) is configured so as not to generate torque outside the range.

On the other hand, the speed control circuit (26) includes a voltage detection section (29) that detects the voltage applied to the burner motor ao+ as a torque conversion value, and a voltage detection section (29) that detects the voltage applied to the burner motor ao+ as a torque conversion value, and a combination of the torque value of the burner motor 00) and the air suction promoting action of the convection fan (3). Based on the detection signal of the voltage detection section (29) and the fan rotation speed storage circuit (3o) in which the value of the fan rotation speed is readably written in relation to the torque value which is set as an appropriate value by measurement in advance based on the relationship. and a speed switching circuit (31) which generates a switching output so as to operate the fan at a predetermined number of rotations read from a predetermined location of the memory circuit (30). During load operation, the fan motor 0υ is operated at high rotation speed, and when the room temperature is low and high load operation is performed, the fan motor 0υ is operated at low rotation speed.

A safety circuit is further attached to the speed control circuit (26), and this safety circuit is formed of an abnormality detecting means (32), a speed changing means (33), and an abnormality stopping means (34).

The abnormality detection means (32) receives the detection signal from the voltage detection section (29) and compares the upper limit setting torque with the lower limit setting torque, and when the detected torque value is larger than the upper limit setting torque, deceleration is performed. A signal is output, and when the torque is smaller than the lower limit set torque, a speed increase signal is output.

On the other hand, the speed changing means (33) receives the output signal of the abnormality detecting means (32) and gives a deceleration output to the fan motor (11) to further reduce the speed by the H speed signal,
A speed increase output that further increases the speed is given by the speed increase signal to forcibly increase or decrease the speed.

Further, the abnormality stopping means (34) receives the output signal of the abnormality detection means (32) and the speed signal of the fan motor Ou, and detects that the fan motor 0υ has decreased to the lower limit set speed,
Moreover, the combustion operation is stopped by stopping the burner motor (101) when the deceleration signal is being output, and when the fan motor (11) has risen to the upper limit set speed and the speed increase signal is being output. The structure is designed to generate a stop output that causes the

The operation of the warm air heater having the configuration described above will be briefly described.

In a hot air heater, when the amount of air sent to the burner head αe with the burner motor 0ω decreases due to the light specific gravity when the room temperature rises, that is, when the burner motor load becomes lighter and the motor current or motor applied voltage becomes smaller, the convection fan By increasing the motor speed (3), the internal pressure (P) (see Figure 2) increases and the amount of air increases.

Conversely, when the specific gravity of the air increases as the room temperature decreases and the motor load increases, the motor speed of the convection fan (3) is lowered to lower the internal pressure CP) and the amount of air decreases.

In this way, combustion can be stabilized by replenishing an appropriate amount of combustion air regardless of variations in the load on the burner motor α0.

During this combustion operation, if the amount of air supply is reduced due to, for example, a back wind from the chimney, the burner motor load increases and the torque exceeds the upper limit set value.

As a result, the abnormality detection means (32) detects the step (
As shown in step (b), it detects that the burner motor applied voltage (VH) is higher than the upper limit setting torque corresponding voltage (vrl()) and outputs a deceleration signal, and thus the speed changing means (33) decelerates as in step (b). output, and the fan motor (1
Decrease the speed of 1l.

By this deceleration, the motor speed of the convection fan (3) is lowered to the lower limit setting speed, so that combustion is stabilized and at the same time,
If the torque becomes smaller than the upper limit set value, the combustion operation is continued (step (d)()));
If the torque is still larger than the upper limit setting torque, the abnormal stop means (34) issues a stop output (step (c)), and the hot air heater stops the combustion operation (step (h)).

Apart from this, the same thing happens when the burner motor load decreases due to external factors and the torque falls below the lower limit set value. It will cause it to stop.

By operating the safety device in this manner, backfire and gas leakage from the burner can be prevented.

Note that the fan rotation speed storage circuit (30) and the abnormality detection means (32) can be easily configured in a microcomputer that forms the core of the control section.

(Effect of the invention) The effects of the present invention are as follows.

If a stable combustion state cannot be maintained by controlling the air volume of the convection fan (3) due to external factors such as head wind from the exhaust passage (24) or negative indoor pressure, the safety device will activate and stop combustion. It can reliably prevent backfire from the burner and gas leakage from the combustion chamber.Furthermore, even if the draft head of the exhaust passage (24) is too strong and the combustion air volume increases too much, the safety device is activated as well, so the lift Problems such as disappearance and CO generation can also be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control circuit according to an embodiment of the present invention;
Figure 2 is a schematic structural diagram of the hot air heater, and Figure 3 is the same.
FIG. 4 is a detailed structural view of the rotary burner in the figure, and FIG. 4 is a flow diagram showing the operation of the safety device in FIG. (11... Heat exchanger, (2)... Rotary burner, (3)... Convection fan, (7)... Combustion chamber, (8)... Oil pump, (9)...・Burner fan, blower...air suction port, (24)...exhaust passage, (32)...abnormality detection means, (33)...speed change means, (34)...abnormality stop means Fig. 2 11 Fan motor Fig. 3 Fig. 4

Claims (1)

[Claims] 1. Combustion chamber (7) connected to exhaust passage (24) such as chimney
A heat exchanger (1) with a built-in heat exchanger (1), an oil pump (8) and a burner fan (9) are connected to a variable torque type burner motor (10).
The oil pump (8) generates combustion gas that is a mixture of the vaporized fuel spouted out and the air sucked from the air suction port (12) by the burner fan (9), and the combustion chamber (
7), and a variable speed fan motor (11) that changes the rotation speed according to the torque level of the burner motor (10),
In a hot air heater equipped with a convection fan (3) that promotes air suction at the air suction port (12) by supplying air to the air suction port (12), the torque of the burner motor (10) an abnormality detection means for detecting the detected value and outputting a deceleration signal when the detected value is larger than the upper limit setting torque and an accelerating signal when it is smaller than the lower limit setting torque with respect to the upper limit setting torque and the lower limit setting torque ( 32) and
Upon receiving the signal from the abnormality detection means (32), the speed changing means ( 33) and stopping the combustion operation when the fan motor (11) has reached the lower limit set speed and the deceleration signal is output, and when the fan motor (11) has reached the upper limit set speed and the speed increase signal is output. 1. A safety device for a hot-air heater, comprising: an abnormality stop means (34) that generates a stop output.