JPH087235Y2 - Blower rotation speed correction device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device which is attached to a boiler or the like, and which mainly corrects the amount of air blown by a blower that feeds combustion air in response to changes in temperature such as the season.

[0002]

2. Description of the Related Art Conventionally, a commercial AC power source is often used as a drive power source for thermal equipment such as a boiler, and an AC blower drive motor attached to the boiler is also used. Therefore, in summer when the atmospheric temperature is high, the amount of air is insufficient and it becomes impossible to maintain a good combustion state.
Also, in winter when the atmospheric temperature is low, the amount of air is excessive, so it is necessary to reduce the amount of air blown. Therefore, in order to obtain the optimal air flow rate according to the atmospheric temperature of each season, either adjust the damper manually installed at the intake inlet of the blower or measure the intake air temperature with a temperature sensor, A correction calculation is performed to automatically control the damper described above, or an inverter is used to automatically control the rotation speed.

[0003]

However, in the above-mentioned manual adjustment, in a region where the temperature changes drastically, a troublesome work of adjusting the damper occurs each time. Also, if the boiler is operated without forgetting the adjustment of the damper, there is a problem in terms of safety due to the generation of CO due to poor combustion and the occurrence of flame extinction. An automatic control device provided with a temperature sensor and an arithmetic unit requires an expensive arithmetic unit, has a complicated circuit, and is expensive. Therefore, in view of the above problems, the present invention aims to provide an inexpensive blower rotation speed correction device that automatically corrects the amount of air blown to the combustion device in response to seasonal temperature changes. Is.

[0004]

That is, the present invention comprises a drive motor for driving a blower for supplying combustion air, and an inverter for correcting the blow rate provided between the drive motor and a power source. The thermistor provided in the vicinity of the intake port is connected in series to the frequency setting resistor of the inverter, and the linearizing resistor is connected in parallel with the thermistor.

[0005]

According to the above construction, the thermistor arranged near the intake port of the blower reduces the resistance in response to the rise in temperature, so that the rotation speed of the drive motor is increased and the blown air amount is corrected at a predetermined temperature. The air-fuel ratio can be kept almost constant.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view showing a schematic configuration of a rotation speed correction device for a blower according to the present invention. In the figure, reference numeral 1 denotes a blower for feeding combustion air to a combustion device (not shown) such as a boiler, which has an intake port 1a opened in the center. Two
Is a drive motor for driving the blower 1, and 3 is a coupling.

In the rotation speed correction device for a blower according to the present invention, an inverter 5 is provided between the drive motor 2 and the AC power source 4, and the output frequency is adjusted by the operation of the inverter 5 in response to temperature changes such as seasons. The electric power having the adjusted output frequency is adjusted and supplied to the drive motor 2 through the wiring 6 to correct the rotation speed. The inverter 5 has a terminal a,
b and c are provided, and a frequency setting resistor 7 is inserted between the terminals a and c. This frequency setting resistor 7
A thermistor 9 is connected in series to the inserted circuit 8 as shown in FIG. 1, and the thermistor 9 is arranged near the intake port 1a of the blower 1 to adjust the frequency according to the intake temperature. A circuit 11 having a linearizing resistor 10 for linearizing the frequency to be adjusted is provided in parallel with the circuit 8.

Next, the operation of the rotation speed correction device of the present invention will be described. The frequency setting resistor 7 is 1 KΩ
1 / 2W, the thermistor 9 is set to 400Ω at 25 ° C, and the linearizing resistor 10 is set to 400Ω 1 / 2W.
Since the frequency adjustment of the inverter 5 is set by the resistance between the terminals a and c and the resistance ratio between the terminals b and c, set frequency = frequency range × (b-c resistance value) / (a-c resistance) Value). Further, the resistance value of the thermistor 9 is 1200 Ω at 25 ° C .... 100 Ω at 25 ° C .... 150 Ω at 400 ° C. 50 ° C. Therefore, the resistance value is linearized by the linearizing resistor 10 at each temperature. become that way. At 0 ° C .... 300 Ω At 25 ° C .... 200 Ω At 50 ° C .... 108 Ω At this time, assuming that the frequency setting resistor 7 and the set value are RVset, for example, the resistance ratio between a-c and b-c is At 0 ° C .... (RVset) / (1300) At 25 ° C .... (RVset) / (1200) At 50 ° C .... (RVset) / (1108) Therefore, the set frequencies at 25 ° C. and 50 ° C. are 1.08 times at 25 ° C. and 1.17 times at 50 ° C., respectively, with respect to the set frequency at 0 ° C. On the other hand, the amount of air blown by the blower 1 changes as the intake air temperature changes, and when the mass flow rate is 25 ° C. and 50 ° C., compared to the amount of air blown at 0 ° C., when the temperature is 25 ° C. (273) / ( 273 + 25) ≒ 0.9
2 times at 50 ° C ... (273) / (273 + 50) ≈0.8
It will be 5 times. The amount of air blown by the blower 1 is proportional to the rotation speed of the blower 1, and therefore the temperature is corrected by the thermistor 9 so that the amount of air blown at 25 ° C. and 50 ° C.
The air flow rate at is as follows. At 25 ° C ... 1.08 × 0.92≈0.99 times At 50 ° C ... 1.17 × 0.85≈0.99 times As described above, the air flow rate is corrected at each temperature, and the air-fuel ratio is corrected. Can be kept substantially constant, so that the combustion device can automatically maintain a good combustion state.

[0009]

As described above, according to the present invention, the inverter is arranged in the circuit of the drive motor of the blower for feeding the combustion air, and the thermistor is provided in the vicinity of the intake port of the blower to change the seasonal temperature. Since the amount of air blown to the combustion device is corrected in accordance with the above, the combustion device can always maintain a good combustion state automatically. Further, this rotation speed correction device does not require an expensive computing unit as in the conventional case and can be constructed at a low cost with a simple circuit.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a schematic configuration of a rotation speed correction device of the present invention.

[Explanation of symbols]

 1. Blower 1a. Intake port 2. Drive motor 5. Inverter 7. Frequency setting resistor 9. Thermistor 10. Linearizer resistor

Claims (1)

[Scope of utility model registration request] 1. An air intake port 1a of the blower 1, comprising a drive motor 2 for driving a blower 1 for supplying combustion air, and an inverter 5 for correcting the air flow provided between the drive motor 2 and a power source. A thermistor 9 provided in the vicinity is connected in series to the frequency setting resistor 7 of the inverter 5, and a linearizing resistor is connected in parallel with the thermistor 9.
A blower rotation speed correction device characterized in that 10 is connected.