JP3412333B2 - Wind speed detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind speed detecting device for detecting wind speed.

[0002]

2. Description of the Related Art A conventional wind speed detector will be described with reference to FIG. 3 (see Japanese Patent Laid-Open No. 4-36508). As shown in FIG. 3, the burner 1 was equipped with a wind speed detection device that detects the wind speed of the air supplied from the fan 2. This wind speed detection device was composed of a wind speed sensor 3, a temperature correction sensor 4 for detecting the temperature of air, and a sensor power supply control means 5 for applying a current to the wind speed sensor 3. Further, the fan 2 is provided with an air ratio control device 6 that controls the fan 2 according to the wind speed value of the wind speed sensor 3. Generally, as the wind speed sensor 3, a hot-wire anemometer, a thermistor anemometer, or the like, which utilizes that heat radiation changes depending on the wind speed, is used. The wind speed detected by the wind speed sensor 3 is obtained from the semi-empirical King's law (Equation 1) showing the relationship between the heat radiation (heating input) and the wind speed.

Q / △ T = A + BU ^1/2 ‥‥‥‥‥‥‥‥‥‥‥‥ (Equation 1) However, Q: Heat dissipation (input) △ T: Temperature difference between wind speed sensor and temperature correction sensor A, B: Constant U: Wind speed Incidentally, the sensor power supply control means 5 applies a current to the wind speed sensor 3 so that the wind speed sensor 3 has a constant temperature, that is, the heat radiation amount Q taken to the air is determined by the sensor power supply control means 5. Is equal to the input. Therefore, the input of the sensor power supply control means 5 is substituted for the heat radiation amount Q.

The air ratio control device 6 compares a preset target wind speed with the wind speed of the wind speed sensor 3, and controls the amount of air blown by the fan 2 in a direction to reduce the wind speed deviation.

In this way, the burner 1 is controlled so as to be in the optimum combustion state by detecting and adjusting the excess / deficiency of air.

[0006]

However, in the configuration of the conventional wind speed detecting device, when the burner 1 starts ignition while the wind speed sensor 3 is activated, as shown in FIG. The maximum allowable current is applied from the sensor power supply control means 6, and the maximum allowable current continues to be applied to the wind speed sensor 3 until the temperature of the wind speed sensor 3 rises and approaches a constant temperature. Since the temperature of the wind speed sensor 3 rises while heat is taken by the air, the temperature difference ΔT also naturally increases.
On the other hand, since the maximum allowable current is applied, the heat radiation amount Q into which the input of the sensor power supply control means 5 is substituted becomes maximum. Therefore, there is a problem that the wind speed of the wind speed sensor 3 calculated from (Equation 1) shows a very large numerical value compared to the actual wind speed, and as a result, the burner 1 cannot be controlled to the optimum combustion state.

If the wind speed sensor 3 is not used when the wind speed sensor 3 is started, the combustion state cannot be maintained due to air resistance due to wind resistance and air shortage.

Next, when the amount of oil or dust attached to the wind speed sensor 3 increases, the heat transfer coefficient from the wind speed sensor 3 to the air changes. Therefore, there is a problem that the wind speed calculated from (Equation 1) showing the relationship between the heat radiation and the wind speed is different from the actual wind speed, and as a result, the burner 1 cannot be controlled to the optimum combustion state.

The wind speed sensor 3 must be kept at a constant temperature so that the wind speed sensor 3 can always measure the wind speed. Therefore, since the current is continuously applied to the wind speed sensor 3 from the sensor power supply control means 5, there is a problem that an electric charge is required.

Further, since the characteristics of the wind speed sensor 3 itself change due to the change over time of the wind speed sensor 3, there is a problem that the wind speed of the wind speed sensor 3 has a large error. As a result, the burner 1 cannot be controlled to the optimum combustion state. .

The present invention is intended to solve the above problems, and an object thereof is to maintain an optimum combustion state even when the wind speed sensor is started.

[0012]

In order to achieve the above object, the wind speed detecting device of the present invention comprises a wind speed sensor which self-heats by applying an electric current, a sensor temperature detecting section which detects the temperature of the wind speed sensor, and a wind speed sensor. A sensor power supply control unit that applies a current to the wind speed sensor to maintain a constant temperature, a constant temperature calculation unit that calculates the wind speed from the current applied to the wind speed sensor by the sensor power supply control unit, and a time of the wind speed sensor from the temperature of the wind speed sensor. A temporal temperature change calculation unit for calculating a dynamic temperature change,
A constant current calculation unit that calculates the wind speed from the temporal temperature change of the wind speed sensor, and a wind speed calculation selection unit that selects the constant temperature calculation unit or the constant current calculation unit from the temperature of the wind speed sensor are provided.

[0013]

According to the present invention, according to the problem solving means, the maximum permissible current is applied to the wind speed sensor from the sensor power supply control means when the wind speed sensor is activated, and the maximum permissible current is applied to the wind speed sensor until the temperature of the wind speed sensor rises and approaches the constant temperature. Continue to be done.
At that time, if the burner starts the ignition operation and the wind speed calculation selection unit selects the constant current time calculation unit from the temperature of the wind speed sensor detected by the sensor temperature detection unit, the constant current time calculation unit calculates the temporal temperature change. The wind speed is predicted from the temporal temperature change of the wind speed sensor calculated by the unit. After that, when the wind speed sensor reaches a constant temperature, the wind speed calculation selection unit selects the constant temperature calculation unit. Then, the constant temperature calculation unit calculates the actual wind speed from the current applied to the wind speed sensor by the sensor power supply control means.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a burner 7 is provided with a proportional valve 8 and a fan 9 for supplying fuel and air, respectively, on the upstream side of the burner 7, and the combustion chamber 1 on the downstream side of the burner 7.
0 and a heat exchanger 11 are provided. On the outlet side of the fan 9, there are provided a wind speed sensor 12 that self-heats when an electric current is applied and a temperature correction sensor 13 that detects the temperature of the air. Reference numeral 14 denotes an air ratio control device, which includes a sensor temperature detection unit 15 that detects the temperature of the wind speed sensor 12, and a sensor temperature detection unit 1.
5, a temporal temperature change calculation unit 16 that calculates a temporal temperature change from the output of 5, and a wind speed calculation selection unit 17 that selects the wind speed calculation method of the wind speed sensor 12 based on the temperature deviation between the temperature of the wind speed sensor 12 and its constant temperature. Output of the sensor power supply control means 18 for applying a current to the wind speed sensor 12 so as to maintain the wind speed sensor 12 at a constant temperature, and the sensor power supply control means 18 when the wind speed calculation selection part 17 determines that the temperature deviation is within the set deviation value. Constant temperature calculation unit 19 that calculates the wind speed from the constant current calculation unit 20 that calculates the wind speed from the output of the temporal temperature change calculation unit 16 when the wind speed calculation selection unit 17 determines that the temperature deviation is outside the set deviation value. And a wind speed setting means 21 for setting a target wind speed
And an air ratio control means 22 that compares the wind speed calculated by the constant temperature time calculation section 19 or the constant current time calculation section 20 with the target wind speed and outputs a control signal according to the wind speed deviation between the two. The fan drive circuit 23 drives and controls the fan 9 in response to the signal, and the proportional valve drive circuit 25 drives the proportional valve 8 in response to the setting signal of the combustion amount setting means 24.

Next, the start-up of the wind speed sensor 12 having the above structure will be described. As shown by the dotted line in FIG. 2, the sensor power supply control means 18 controls the temperature θ and the constant temperature θ of the wind speed sensor 12.
_A current is applied to the wind speed sensor 12 in accordance with the temperature deviation (θ _S −θ) from _S. Especially, in the initial stage of starting the wind speed sensor 12,
Since the temperature deviation (θ _S −θ) is positive and is larger than the constant temperature deviation value, the sensor power supply control means 18 causes the wind speed sensor 12 to operate.
The maximum permissible current, that is, a constant current is applied to the wind speed sensor 12 to rapidly raise the temperature. After that, the temperature deviation (θ
_{When S−} θ) is within the constant temperature deviation value, the sensor power supply control means 18 reduces the current applied to the wind speed sensor 12 in accordance with the temperature deviation (θ _S −θ) and puts the wind speed sensor 12 into a standby state where the temperature is kept constant. Transition. Generally, constant temperature θ _S is 150 ℃
In the case of, the starting time of the wind speed sensor 12 is about 20 to 30 seconds.

Although the wind speed sensor 12 is kept at a constant temperature, the temperature difference ΔT between the wind speed sensor 12 and the temperature correction sensor 13 may be kept constant.

Next, the ignition operation of the burner 7 while the wind speed sensor 12 is being activated will be described with reference to FIG. At first,
The air ratio control means 22 outputs a preset ignition rotation speed to the fan drive circuit 26, and the fan 9 starts blowing air. At the same time, the wind speed calculation selection unit 17 selects the calculation method of the current wind speed. For example, when it is determined that the temperature deviation (θ _S −θ) is outside the constant temperature deviation value (the sensor power supply control means 18 causes the wind speed sensor 12 to have the maximum allowable current). Is applied), and the constant current operation unit 20
Select. Next, the constant current time calculation unit 20 calculates the time constant T using (Equation 2) from the time temperature change of the wind speed sensor 12 calculated by the time temperature change calculation unit 16 from the output of the sensor temperature detection unit 15. The actual wind speed can be predicted from the relationship between the wind speed and the time constant T obtained in advance.

T = (t ₀ −t) / ln (θ ₀ / θ) (Equation 2) T: time constant t ₀ : initial time t: current time θ ₀ : initial temperature of wind speed sensor θ: current temperature of the wind speed sensor, and the air ratio control means 22 compares the target wind speed set by the wind speed setting means 22 with the wind speed predicted by the constant current calculation unit 20, and drives the fan in a direction to reduce this wind speed deviation. The circuit 23 is controlled to control the amount of air blown by the fan 9. Also,
The combustion amount setting means 24 controls the proportional valve drive circuit 25 according to the set combustion amount to start combustion. Since the blow rate is optimized in this way, the burner 7 can maintain the combustion state.

Subsequently, when the wind speed calculation selecting unit 17 determines that the temperature deviation (θ _S −θ) is within the constant temperature deviation value as a result of the temperature increase of the wind speed sensor 12, the constant temperature calculating unit 19 is selected. Then, as in the conventional example, the constant temperature operation unit 19 calculates the actual wind speed using (Equation 1) from the current value of the sensor power supply control means 18 and the air temperature of the temperature correction sensor 13.
Then, the air ratio control means 22 compares the target wind speed output by the wind speed setting means 22 with the wind speed calculated by the constant temperature calculation unit 19, and controls the fan drive circuit 23 to reduce the wind speed deviation to control the fan 9. The burner 7 can maintain the optimum combustion state because the amount of air blown is optimized.

The wind speed calculated by the constant temperature calculation unit 19 is more accurate than the wind speed calculated by the constant current calculation unit 20 and predicted using the time constant T.

Next, the ignition operation of the burner 7 during standby of the wind speed sensor 12 (after completion of startup) will be described. Since the wind speed sensor 12 is in standby, that is, the temperature deviation (θ _S −θ) is within the constant temperature deviation value, the constant temperature calculation unit 19 selected by the wind speed calculation selection unit 17 calculates the actual wind speed from (Equation 1). Then, the air ratio control means 22 compares the target wind speed output by the wind speed setting means 22 with the wind speed calculated by the constant temperature calculation unit 19, and controls the fan drive circuit 23 to reduce the wind speed deviation to control the fan 9. Control the air flow rate of. Since the blow rate is controlled to an appropriate value in this way, the burner 7 can maintain the optimum combustion state.

When the standby time has passed for a certain period of time, the constant temperature of the wind speed sensor 12 is decreased to the second constant temperature θ _S2 . At that time, the sensor power supply control means 18 reduces the current and applies it to the wind speed sensor 12 according to the temperature deviation (θ _S2 −θ) between the temperature θ of the wind speed sensor 12 and the second constant temperature θ _S2 . As a result, the electricity bill can be significantly reduced.

Next, the ignition operation of the burner 7 during the second standby of the wind speed sensor 12 will be described. First, the constant temperature of the wind speed sensor 12 is returned to the original value and set to θ _S. Since the temperature deviation (θ _S −θ) is positive and is larger than the constant temperature deviation value, the sensor power supply control means 18 causes the wind speed sensor 1 to operate.
The maximum allowable current is applied to 2 and the temperature of the wind speed sensor 12 rapidly rises. Then, when the flip purge is completed, the temperature deviation (θ _S −θ) becomes small near the constant temperature deviation value, so the wind speed calculation selecting section 17 selects the constant current time calculating section 20 at the initial stage of ignition, but for a short time. Then, the wind speed calculation selection unit 17 selects the constant temperature calculation unit 19. That is, even if the constant temperature of the wind speed sensor 12 during standby is lowered, the accuracy of the wind speed is restored in a short time.

Next, a method of preventing the accuracy of the wind speed sensor 12 from deteriorating due to the adhesion of oil or dust to the wind speed sensor 12 will be described. Since the heat capacity of the wind speed sensor 12 increases by the amount of the oil or dust attached, the temperature increase of the wind speed sensor 12 during startup becomes slow. That is, by using the relationship between the amount of oil or dust that has been obtained in advance and the temperature rise of the wind speed sensor 12, the time of the wind speed sensor 12 immediately after the start of the wind speed sensor 12 and when the fan drive circuit 23 is stopped. The constant temperature calculation unit 19 changes the constants A and B in (Equation 1) based on the temperature change. As a result of this change, the influence of oil and dust can be suppressed.

Further, a method of preventing the accuracy of the wind speed sensor 12 from deteriorating due to a change with time of the wind speed sensor 12 will be described. When the wind speed sensor 12 is in the standby mode or the second standby mode and the wind speed of the constant temperature time calculation unit 19 is no wind for a certain period, the constant temperature time calculation unit 19 detects the temperature difference ΔT between the wind speed sensor 12 and the temperature correction sensor 13 and the sensor. The constant A of (Equation 1) is changed from the input (heat radiation amount Q) from the power supply control means 18.
As a result of this change, the influence of the change over time of the wind speed sensor 12 can be suppressed.

[0027]

As described above, according to the wind speed detecting device of the present invention, the following effects can be obtained.

(1) Since the constant-current-time arithmetic unit capable of predicting the wind speed from the temporal temperature change of the wind speed sensor is provided, the wind speed can be predicted even when the wind speed sensor is activated.

(2) When the wind speed calculation selection unit determines that the temperature of the wind speed sensor is a constant temperature, the constant temperature calculation unit calculates the wind speed, and the wind speed calculation selection unit sets the temperature of the wind speed sensor to a non-constant temperature. If it is determined that the constant current calculation unit calculates the wind speed, the burner can always be maintained in the optimum combustion state.

(3) When the wind speed sensor is activated, the constant temperature operation section is corrected according to the temporal temperature change of the wind speed sensor.
The error of the wind sensor due to oil and dust can be suppressed.

(4) When the wind speed of the constant temperature operation part is no wind for a certain period, the constant temperature level of the wind speed sensor is lowered to maintain the wind speed sensor at another constant temperature, so that the electricity bill can be reduced.

(5) When the wind speed of the constant temperature calculation unit is no wind for a certain period of time, the constant temperature calculation unit is corrected, so that the error of the change over time of the wind speed sensor can be suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a wind speed detection device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the wind speed sensor of the same device.

FIG. 3 is a block diagram of a conventional wind speed detection device.

FIG. 4 is a characteristic diagram of a wind speed sensor of the device.

[Explanation of symbols]

12 Wind speed sensor 15 Sensor temperature detector 16-hour temperature change calculator 17 Wind speed calculation selection section 18 Sensor power supply control means 19 Constant temperature calculation unit 20 Constant current calculation unit

Front page continuation (72) Inventor Shiro Takeshita 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-61-22217 (JP, A) JP-A-4-36508 (JP) , A) JP-A-8-312947 (JP, A) JP-A-8-303766 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01P 5/10 F23N 5/18 101

Claims (5)

(57) [Claims] 1. A wind speed sensor that self-heats when an electric current is applied, a sensor temperature detection unit that detects the temperature of the wind speed sensor, and a sensor power supply that applies a current to the wind speed sensor so as to maintain the wind speed sensor at a constant temperature. A control unit, a constant temperature time calculation unit that calculates the wind speed from the current applied to the wind speed sensor by the sensor power supply control unit, and a temporal temperature change calculation that calculates the temporal temperature change of the wind speed sensor from the temperature of the wind speed sensor. A constant current calculation unit that calculates a wind speed from a temporal temperature change of the wind speed sensor, and a wind speed calculation selection unit that selects the constant temperature calculation unit or the constant current calculation unit from the temperature of the wind speed sensor. An equipped wind speed detector. 2. When the wind speed calculation selection unit determines that the temperature of the wind speed sensor is a constant temperature, the constant temperature calculation unit calculates the wind speed, and the wind speed calculation selection unit sets the temperature of the wind speed sensor to a non-constant temperature. The wind speed detecting device according to claim 1, wherein the constant current calculation unit calculates the wind speed when it is determined that there is. 3. The constant temperature calculation unit is corrected according to a temporal temperature change of the wind speed sensor when the wind speed sensor is activated.
The wind speed detection device described. 4. The wind speed detecting device according to claim 1, wherein, when the wind speed of the constant temperature time calculation unit is no wind for a certain period, the constant temperature level of the wind speed sensor is lowered to maintain the wind speed sensor at another constant temperature. 5. The wind speed detecting device according to claim 1, wherein when the wind speed of the constant temperature calculation unit is no wind for a certain period, the constant temperature calculation unit is corrected.