Method for measuring number of rotations of large-sized air blower for air conditioner

Abstract

To carry out measurement of the number of rotations of an air blower for an air conditioner, while making preparation operations before the measurement simple and time-saving, prevent a sensor for measuring the number of rotations of the air blower from being sucked into a suction port of the air blower during the measurement, and prevent damage to the air blower and the sensor.SOLUTION: A number-of-rotation measurement method for measuring the number of rotations of a large-sized air blower for an air conditioner includes: a first step (S1) of measuring multiple times the number of rotations of the air blower by using a laser distance sensor; a second step (S2) of determining the average value of the number of rotations of the air blower and the value of standard deviation from the measured number of rotations of the air blower; a third step (S3) of extracting outliers from the measured number of rotations of the air blower, and excluding the outliers of the number of rotations of the air blower; a fourth step (S4) of determining the average value of the number of rotations of the air blower and the value of standard deviation from the remaining number of rotations of the air blower after excluding the outliers of the number of rotations of the air blower; and a fifth step (S5) of determining the average value of the number of rotations of the air blower determined in the fourth step as the final number of rotations of the air blower.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for measuring the rotation speed of a large-sized blower attached to an air conditioner. [Background technology]

[0002] Traditionally, large-volume air conditioners used in large facilities such as office buildings, hospitals, and commercial buildings are equipped with large fans. After the product (air conditioner) is completed, the fan's rotation speed is measured to check its performance and confirm whether it meets the designed rotation speed.

[0003] One known method for measuring the rotation speed of a blower is to use a reflective optical sensor. This measurement method uses a reflective optical sensor. A reflective sticker is attached to a predetermined location on the rotating part of the blower, such as the fan blade. For example, if the fan has eight blades, a reflective sticker is attached to one of the fan blades. The reflective optical sensor is then installed adjacent to the reflective sticker. The sensor's position is adjusted so that the light emitted from the reflective optical sensor strikes the reflective sticker attached to the fan blade. The reflective optical sensor emits light from its light-emitting element, which reflects off the reflective sticker attached to the fan blade. The reflected light is then detected by its light-receiving element. The time required for one rotation of the fan blade, i.e., the rotation period, can be calculated by determining the time between the detection of light by the reflective optical sensor and the detection of the next light due to the rotation of the fan blade. The rotation period can then be used to calculate the rotation speed of the blower. This allows the rotation speed of the blower to be measured.

[0004] Another known method for measuring rotation speed is to use a magnetic proximity sensor to measure the rotation speed of a fan. In this method, a magnetic proximity sensor is installed close to the fan or rotating body, and the sensor detects magnetic changes caused by changes in distance due to rotation. In other words, if a fan has eight fan blades, the magnetic proximity sensor detects the fan blades eight times. By calculating the time it takes for these eight detections to occur, the time it takes for the fan blades to rotate once, i.e., the rotation period, can be calculated, and the rotation speed of the fan can be calculated from this rotation period. This allows the rotation speed to be measured.

[0005] However, in a method of measuring the rotation speed of a fan using a reflective optical sensor, a reflective sticker must be attached to a rotating part such as a fan blade as a preparatory step before measurement. Furthermore, the reflective optical sensor must be precisely positioned so that its light accurately strikes the reflective sticker attached to the fan blade. This results in time-consuming preparatory steps and poor workability. Furthermore, because the reflective optical sensor is installed right next to the fan, in the case of a large fan, vibrations during operation and the influence of the intake airflow can cause the reflective optical sensor to vibrate during measurement, making it difficult to accurately measure the fan rotation speed. Furthermore, because the reflective optical sensor is installed right next to the fan's intake port, there is a risk that the reflective optical sensor may be sucked into the intake port of the fan during measurement, potentially damaging the fan and the sensor.

[0006] Furthermore, even in the method of measuring the fan rotation speed using a magnetic proximity sensor, the magnetic proximity sensor must be precisely positioned as a preparatory step before measurement in order for the sensor to accurately detect the fan blades. This requires time-consuming preparatory work and poor workability. Furthermore, because the magnetic proximity sensor is installed in close proximity to the fan, vibrations from the fan during operation and the influence of the intake airflow can cause the magnetic proximity sensor to vibrate during measurement, which can lead to inaccurate measurement of the fan rotation speed. Furthermore, because the magnetic proximity sensor is installed in close proximity to the fan intake, there is a risk that the magnetic proximity sensor may be sucked into the intake during measurement, potentially damaging the fan and the sensor. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of these problems, and its purpose is to improve workability by simplifying the preparation work before measuring the rotation speed of a blower, to eliminate the problem of not being able to accurately measure the rotation speed of a blower during measurement due to the influence of operating vibrations of the blower and the intake airflow, and to prevent the device for measuring the rotation speed of the blower from being sucked into the intake port of the blower, thereby preventing damage to the blower and sensor. [Means for solving the problem]

[0008] The present invention provides a method for measuring the rotation speed of a large fan for an air conditioner, comprising: a first step of measuring the rotation speed of the fan multiple times using a laser distance sensor; a second step of determining an average value and a standard deviation of the fan rotation speed from the rotation speeds measured multiple times in the first step; a third step of extracting outliers from the rotation speeds of the fan measured multiple times based on the average value and standard deviation of the fan rotation speed determined in the second step and removing the extracted outliers of the fan rotation speed; a fourth step of determining an average value and a standard deviation of the fan rotation speed from the remaining rotation speeds of the fan after removing the outliers of the fan rotation speed in the third step; and a fifth step of determining whether the standard deviation of the fan rotation speed determined in the fourth step is equal to or less than a predetermined value, and if it is equal to or less than the predetermined value, determining the average value of the fan rotation speed determined in the fourth step as the final rotation speed of the fan. [Effects of the Invention]

[0009] According to the present invention, by using a laser distance sensor, the preparation work before measurement can be made easy and hassle-free, thereby improving workability. In addition, the laser distance sensor can be installed at a certain distance from the air intake of the fan, and during measurement, the laser distance sensor is not affected by the vibrations of the fan or the intake airflow, preventing the laser distance sensor from shaking and eliminating the problem of inaccurate measurement of the fan rotation speed. Moreover, the laser distance sensor can be prevented from being sucked into the air intake of the fan during measurement, eliminating the problem of possible damage to the fan and sensor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the configuration of equipment used in a method for measuring the rotation speed of a large fan for an air conditioner according to the present invention; [Figure 2] FIG. 2 is a perspective view showing the shape of a blower. [Figure 3] 1 is a flowchart of the calculation process of the method for measuring the rotation speed of a large fan for an air conditioner according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the method for measuring the rotation speed of a large-sized fan for an air conditioner according to the present invention will be described. The method for measuring the rotation speed of a large fan for an air conditioner according to this embodiment is a method for measuring the rotation speed of a large fan attached to a high-volume air conditioner used in large facilities such as office buildings, hospitals, and commercial facilities, to check whether the fan satisfies the designed rotation speed after the product (air conditioner) is completed, in other words, to measure the rotation speed of the fan as a performance check. In this rotation speed measurement method, as will be described later, by installing the laser distance sensor at a position some distance from the intake port of the fan, the laser distance sensor is not affected by the operating vibrations of the fan or the intake airflow during measurement, allowing the fan rotation speed to be measured accurately, and furthermore, the problem of damage to the fan and sensor can be eliminated. Furthermore, when measuring the rotation speed, sudden large vibrations may occur on the fan side, causing the measured rotation speed to deviate significantly. However, by extracting and excluding these significantly deviated values ​​as outliers, the final rotation speed of the fan can be determined with high accuracy.

[0012] (Device configuration) Fig. 1 is a diagram showing the configuration of an apparatus used in a method for measuring the rotation speed of a large fan for an air conditioner, and Fig. 2 is a perspective view showing the shape of the fan. As shown in Fig. 1, a large blower 1 for an air conditioner has an inlet 11 for drawing in air and an outlet 12 for discharging the air, and also has a motor 13 and fan blades 14 rotated by this motor 13 inside, and the air drawn in by the fan blades 14 is discharged from the outlet 12. Although not shown, the blower 1 supplies air to an air conditioner or a part thereof. Furthermore, the basic shape of the blower 1 itself is, as shown in Fig. 2, equipped with multiple fan blades 14 rotated by a motor (not shown), drawing in air from the center of rotation and discharging the drawn air to the surrounding area. The equipment used in the method for measuring the rotation speed of this large air conditioner blower 1 is a laser distance sensor 20 installed next to the blower 1, as shown in Figure 1, and a processing device 30 that performs various processing tasks based on information obtained from the laser distance sensor 20.

[0013] Laser distance sensor 20 itself detects the distance from the object to be detected by irradiating the object with laser light and detecting the laser light reflected from the object, but here, laser distance sensor 20 is equipped with a high-speed counter unit 21 and a PLC (Programmable Logic Controller) 22 to measure the rotation speed of blower 1. The rotation speed of blower 1 to be measured is the rotation speed of fan blades 14 of blower 1. This laser distance sensor 20 is installed at a position some distance from intake port 11 of blower 1, here 1 to 2 m away, and the direction of irradiation of the laser light is directed toward fan blades 14 of blower 1.

[0014] To measure the rotation speed of the blower 1 using the laser distance sensor 20, the laser distance sensor 20 focuses its laser on a position (detection target) near the center of the fan blade 14 of the blower 1, and sets this as reference distance 0. Subsequently, as the fan blade 14 of the blower 1 rotates, the distance detected by the laser distance sensor 20 varies from reference distance 0, which is a position near the center of the fan blade 14, depending on the rotation of the fan blade 14 and the shape of the fan blade 14. For the distance detected by the laser distance sensor 20, a threshold value is set for reference distance 0. The threshold value is, for example, 5 mm, i.e., ±5 mm from reference distance 0. However, it is not limited to 5 mm. When the fan blade 14 rotates, the distance detected by the laser distance sensor 20 counts as one when it deviates from the threshold value (±5 mm from reference distance 0), resets when it re-enters the threshold, and counts as one when it deviates from the threshold value again. This count is integrated as a pulse signal by the high-speed counter unit 21.

[0015] Next, the PLC 22 calculates the rotation speed of the blower 1 from the pulse signals counted by the high-speed counter unit 21. That is, if the number of fan blades 14 in the blower 1 is, for example, six, the PLC 22 calculates the time it takes for the high-speed counter unit 21 to count six pulse signals (when the six fan blades 14 make one rotation), i.e., the rotation period, and calculates the rotation speed of the blower 1 from this rotation period.

[0016] The processing device 30 is a computer that stores various programs and performs various processing operations using the stored programs. In this processing device 30, various processing operations are performed based on the rotation speed of the fan 1 measured using the laser distance sensor 20, and the final rotation speed of the fan 1 is determined. Specific processing operations will be described later.

[0017] (Method for measuring the rotation speed of large air conditioner fans) FIG. 3 is a flowchart of the calculation process of the method for measuring the rotation speed of a large fan for an air conditioner. As shown in the figure, the method for measuring the rotation speed of a large blower for an air conditioner includes a first step (S1) of measuring the rotation speed of blower 1 multiple times, a second step (S2) of determining the average value and standard deviation of the rotation speed of blower 1 from the rotation speed of blower 1 measured multiple times, a third step (S3) of extracting outliers from the rotation speed of blower 1 measured multiple times and excluding the outliers of the rotation speed of blower 1, a fourth step (S4) of determining the average value and standard deviation of the rotation speed of blower 1 from the remaining rotation speeds of blower 1 after excluding the outliers of the rotation speed of blower 1, and a fifth step (S5) of determining whether the value of the standard deviation of the rotation speed of blower 1 is below a predetermined value, and if it is below the predetermined value, determining the average value of the rotation speed of blower 1 determined in the fourth step as the final rotation speed of blower 1.

[0018] The first step (S1) is a step of measuring the rotation speed of the fan 1 using the laser distance sensor 20. The measurement of the rotation speed of the fan 1 is performed by the laser distance sensor 20 and the high-speed counter unit 21 and PLC 22 provided in the laser distance sensor 20. That is, as described above, the laser distance sensor 20 detects a distance that varies from a reference distance of 0, which is set as the distance to the center position of the fan blade 14 of the blower 1, and outputs a pulse signal each time the detected distance deviates from a set threshold (S1a). The high-speed counter unit 21 counts these pulse signals, and the PLC 22 then calculates the rotation speed of the blower 1 from the pulse signals counted by the high-speed counter unit 21 (S1b). This makes it possible to measure the rotation speed of the blower 1. The rotation speed of the blower 1 is measured multiple times, for example, five times. Note that the number of measurements is not limited to five, and may be any number of times, such as six, seven, or eight.

[0019] The next second step (S2) to fifth step (S5) are steps performed in the processing device 30. The second step (S2) determines the number of measurements i when the laser distance sensor 20 measures the rotation speed of the fan 1 multiple times (here, five times) in the first step (S1) (S2a). If the number of measurements i has not reached five (S2a, NO), measurements are continued until five are reached. Next, when the number of measurements i has reached five (S2a, YES), the average value Na and standard deviation value Nd of the measured rotation speed of the fan 1 are calculated from the five measurements of the rotation speed of the fan 1 (S2b). The standard deviation indicates the degree of dispersion of data on the rotation speed of the fan 1 measured multiple times, and its value Nd can be calculated using the following formula:

[0020]

number

[0021] In the third step (S3), outliers are extracted from the five measurements of the rotation speed of blower 1 using the average value Na and standard deviation value Nd of the rotation speed of blower 1 obtained in the second step, and the extracted outliers of the rotation speed of blower 1 are excluded (S3a). For these outliers, the average value Na of the rotation speed of blower 1 plus the standard deviation value Nd is defined as an upper limit value NH (Na + Nd), and the average value Na of the rotation speed of blower 1 minus the standard deviation value Nd is defined as a lower limit value NL (Na - Nd), and any value falling between the upper limit value NH and the lower limit value NL is defined as an outlier of the rotation speed of blower 1. These outliers of the rotation speed of blower 1 are extracted and excluded.

[0022] Next, it is determined whether the number of outliers in the rotation speed of fan 1 to be excluded is greater than a predetermined number (S3b). This predetermined number is, for example, three. That is, if the number of outliers is less than three among the five measurements of the rotation speed of fan 1 (YES in S3b), the process proceeds to the next fourth step (S4). On the other hand, if the number of outliers is three or more (more than the predetermined number) (NO in S3b), the process returns to the first step (S1) in which the laser distance sensor 20 is used to measure the rotation speed of fan 1 multiple times, and the rotation speed of fan 1 is measured again.

[0023] In the fourth step (S4), the average value Na2 and standard deviation value Nd2 of the rotation speed of the fan 1 are calculated from the remaining rotation speeds of the fan 1 after excluding outliers in the rotation speed of the fan 1 in the third step. The method for calculating the standard deviation value Nd2 of the rotation speed of the fan 1 here is the same as the method for calculating the standard deviation value Nd of the rotation speed of the fan 1 in the second step (S2) described above.

[0024] In the fifth step (S5), it is determined whether the standard deviation value Nd2 of the rotation speed of the fan 1 obtained in the fourth step is equal to or less than a predetermined value K (S5a). Note that the predetermined value K for the standard deviation value Nd2 here is the required measurement accuracy × 2. For example, if the required measurement accuracy is 0.5 rpm, K = 1.0 (0.5 × 2).

[0025] Next, in determining whether the standard deviation value Nd2 of the rotation speed of blower 1 is equal to or less than a predetermined value K, if the standard deviation value Nd2 of the rotation speed of blower 1 is equal to or less than the predetermined value K (S5a, YES), the average value Na2 of the rotation speed of blower 1 calculated in the fourth step is calculated as the final rotation speed of blower 1 (S5b).If the standard deviation value Nd2 of the rotation speed of blower 1 is greater than the predetermined value K (S5a, NO), the process returns to the first step (S1) of measuring the rotation speed of blower 1 multiple times using laser distance sensor 20, and the rotation speed of blower 1 is measured again. In this way, the final rotation speed of the fan 1 can be determined, and this determined final rotation speed of the fan 1 can be used to confirm whether the fan is operating normally (performance confirmation).

[0026] As described above, according to this embodiment, by using laser distance sensor 20 to measure the rotation speed of blower 1, the preparation work before measurement simply involves installing laser distance sensor 20, measuring the distance to the center position of fan blade 14 of blower 1 with laser distance sensor 20, and setting this as reference distance 0, eliminating the need for detailed positioning settings, and eliminating, for example, the need to attach reflective stickers to the fan blades of the blower and the adjustment of their attachment positions. This makes it possible to simplify the preparation work before measurement and improve workability.

[0027] Furthermore, laser distance sensor 20 can be installed at a position some distance away from suction port 11 of blower 1, here 1 to 2 m away from suction port 11 of blower 1, so that during measurement laser distance sensor 20 is not affected by the operating vibrations or suction airflow of blower 1, preventing vibration of laser distance sensor 20 and eliminating the problem of being unable to accurately measure the rotation speed of blower 1. Moreover, because laser distance sensor 20 is installed at a position 1 to 2 m away from suction port 11 of blower 1, it is possible to prevent laser distance sensor 20 from being sucked into suction port 11 of blower 1 during measurement, eliminating the problem of possible damage to blower 1 and laser distance sensor 20.

[0028] Furthermore, when measuring the rotation speed of blower 1, sudden large vibrations on the blower 1 side can result in a large deviation in the measured value of the rotation speed of blower 1. However, a large deviation in the rotation speed of blower 1 can be extracted as an outlier and excluded in the third step (S3), thereby making it possible to obtain a highly accurate value for the rotation speed of blower 1 that is ultimately determined. [Explanation of symbols]

[0029] 1...blower, 11...suction port, 12...discharge port, 13...motor, 14...fan blade, 20...laser distance sensor, 21...high-speed counter unit, 22...PLC, 30...processing device

Claims

1. A method for measuring the rotation speed of a large fan for an air conditioner, comprising: a first step of measuring the rotation speed of the fan multiple times using a laser distance sensor; a second step of determining an average value and a standard deviation value of the fan rotation speed from the fan rotation speed measured multiple times in the first step; a third step of extracting outliers from the fan rotation speeds measured multiple times based on the average value and standard deviation of the fan rotation speeds obtained in the second step, and excluding the extracted outliers of the fan rotation speeds; a fourth step of excluding outliers of the fan rotation speed in the third step, and then calculating an average value and a standard deviation value of the fan rotation speed from the remaining fan rotation speeds; a fifth step of determining whether the value of the standard deviation of the fan rotation speeds obtained in the fourth step is equal to or less than a predetermined value, and if the standard deviation is equal to or less than the predetermined value, determining the average value of the fan rotation speeds obtained in the fourth step as the final fan rotation speed; A method for measuring the rotation speed of a large fan for an air conditioner, comprising:

2. 2. The method for measuring the rotation speed of a large-sized blower for an air conditioner according to claim 1, In the third step, if the number of outlier values ​​of the fan rotation speed to be excluded is greater than a predetermined number, the method for measuring the rotation speed of a large fan for an air conditioner returns to the first step of measuring the fan rotation speed multiple times and measures the fan rotation speed again.

3. 3. The method for measuring the rotation speed of a large-sized blower for an air conditioner according to claim 1 or 2, A method for measuring the rotation speed of a large fan for an air conditioner, in which, when the value of the standard deviation of the fan rotation speed becomes larger than a predetermined value in the fifth step, the method returns to the first step of measuring the fan rotation speed multiple times and remeasures the fan rotation speed.

Images