JPS6290543A - Anemometer calibrating apparatus - Google Patents

Abstract

PURPOSE:To enhance reading accuracy, by arranging a plurality of flow amount measuring nozzles in a wind tunnel main body in order of a larger caliber. CONSTITUTION:The wind tunnel main body 6 mounted to a frame 1 is made of a transparent acrylic resin and an inlet nozzle 7 is provided so as to be communicated with a suction side and a first wind velocity measuring part 8 is formed to the side of the inlet nozzle 7 and, succeedingly, the flow amount measuring nozzle 10 of a second wind velocity measuring part 9 is fixed by a ring plate 11. A flow amount measuring nozzle 12 having a diameter smaller than that of the flow amount measuring nozzle 10 is fixed to an exhaust side by a ring plate 13 and an exhaust pipe 14 is communicated with the end part of the main body 6. The duct hose 15 communicated with a blower 4 is externally fitted to the exhaust pipe 14 of the wind tunnel main body 16. In the case of first difference pressure take-out ports 25, 16, because the caliber of the flow amount measuring nozzle 10 is large, small difference pressure is obtained and, in the case of second difference pressure take-out ports 27, 28, because the caliber of the flow amount measuring nozzle 12 is small, large difference pressure is obtained even in the same flow amount and reading can be easily performed with high accuracy.

Description

[Detailed Description of the Invention] 3. Field of Industrial Use The present invention relates to a wind speed B1 calibration device for calibrating the wind speed B1.
In particular, the present invention relates to a new anemometer calibration device in which a plurality of wind speed measuring sections and a plurality of flow rate measuring nozzles are arranged in order of diameter within a wind tunnel main body having the same diameter.

BACKGROUND OF THE INVENTION Devices for calibrating anemometers generally include a large wind tunnel, a medium-sized wind tunnel dedicated to calibration, and a small portable wind tunnel dedicated to calibration.

In large wind tunnels, a pitot tube is installed at a distance from the wind tunnel wall, and the wind speed is determined from the difference between the total pressure and static pressure.

At the same time, a wind speed sensor is provided in a position close to the pitot tube to obtain an indicated value, and the indicated value of the anemometer is thereby calibrated using the wind speed value determined by the pitot tube as a reference.

A medium-sized wind tunnel dedicated to calibration is equipped with an orifice-type flowmeter in the windpipe, and by reading the differential pressure of this flowmeter with a Genotingen-type differential pressure gauge, the flow rate flowing through the windpipe can be determined.
Wind speed measurement points were set up on the cross section of the wind pipe, and (n
Install an anemometer sensor ~ on the cross section of J, and obtain the indicated value of the anemometer at that time. tAr, lii: The wind speed at which the anemometer sensor is installed is determined from the flow rate determined by ff1, etc., and the indicated value of the anemometer is calibrated based on this wind speed.

In addition, a small portable wind tunnel dedicated to calibration has a nozzle for measuring wind speed and a nozzle for measuring flow rate inside the small wind tunnel, and when changing the wind speed, the flow rate measuring nozzle and the wind speed measuring nozzle must be replaced respectively. Do it by K.

..., the problem that the idea attempts to solve However, conventional wind tunnels have the following problems.

First, in large wind tunnels, accurate calibration cannot be performed unless the tunnel is operated for a long period of time, and since a pitot tube is used, low wind speed calibration is difficult.
The wind speeds are not necessarily the same due to the difference in degrees, and accurate calibration is not possible especially at low wind speeds.7'C.

゛In addition, a medium-sized wind tunnel dedicated to calibration needs to have many wind speed measurement cross sections, and because it needs to have a wind speed cross section with a relatively large diameter, it is relatively large and expensive. The cross section was affected by the blocking effect of the anemometer, and because it was relatively large, it was not possible to make it portable.

Furthermore, in a small portable wind tunnel dedicated to calibration, depending on the wind speed range to be calibrated, it is necessary to replace one or both of the flow rate measurement nozzle and the wind speed measurement nozzle, which is a complicated process, and the fan power is Due to its small size, stability at low flow rates was poor, and calibration at low wind speeds of 1% or less was not possible.

21. Means for Solving the Problems In the present invention, a wind tunnel main body having the same diameter straight tube is mounted on a portable frame, and a plurality of wind speed measuring sections using wind speed sensors etc. are provided in the wind tunnel main body. By arranging multiple flow nozzles in descending order of diameter, anemometer calibration can be performed over a wide range from low wind speeds to relatively high wind speeds, and the cross section of the wind speed measuring section is the same as the main body of the wind tunnel, minimizing blocking effects. To provide an anemometer calibration device with high reading accuracy at a low price and with a large differential pressure.

When the blower controlled by an inverter is started, the blower rotates at a very low speed corresponding to a low frequency of 3 II. When the blower rotates, the airflow enters through the inlet nozzle and Rectified by the rectifier net, the next Km
By passing through the flow nozzle, the airflow becomes uniform with little turbulence and enters the main body of the wind tunnel.

The first wind speed measuring section is located at a position where such uniform airflow with little turbulence can be measured. The airflow is rectified again by the rectifier net, and the first nozzle is activated. By measuring the pressure difference across the nozzle, the flow rate can be measured. The tip of the second nozzle serves as a second measuring section. The anemometer sensor will be installed at its center. Although this field is inside the wind tunnel, since dl<D, it can be regarded as a free DC field. Therefore, the diameter d of the first nozzle is reduced,
Compared to the case where the wind speed iI sensor is placed in the duct, the blocking effect of the sensor part of the anemometer is extremely small.

The airflow is then rectified again and enters the second nozzle.

Current flow can also be determined by measuring the differential pressure across the nozzle. As described above, since L12<dl, the differential pressure at the second differential pressure outlet is larger than the differential pressure at the first differential pressure outlet. Therefore, it is easy to read, and the accuracy of reading and the accuracy of wind speed measurement can be improved. The airflow is then sucked into the blower via the duct hose.

To, Example Hereinafter, one example of implementing the present invention will be explained in detail with reference to the drawings.

1 is a frame-shaped frame, and level-adjustable casters 2 are attached to the lower ends of the pillars at the four corners so that it can be moved and fixed, and a shelf 5 on which the inverter 3 and the blower 4 are mounted is installed at the bottom. A wind tunnel main body 6 having an inner diameter is mounted on the upper surface.

The wind tunnel main body 6 mounted on the frame l is made of transparent acrylic resin or the like, and has an inlet nozzle 7 arranged in series on the intake side, and a first wind velocity 11111 constant part 8 formed on the inlet nozzle 7 side. Next, the flow rate measuring nozzle 10 of the second wind speed measuring section 9 is fixed on the ring plate 11, and the flow rate measuring nozzle 10 of the second wind speed measuring section 9 is fixed on the exhaust side. IC4ft
Flow rate measuring nozzle 12', (I
It is fixed with an induction rate of 13, and a 111 air pipe 1 is installed at the end.
Connect 4.

A duct hose 15 that communicates with the blower 4 is inserted into the exhaust vibrator 14 of the wind tunnel main body 6.

The inlet nozzle 7 connected to the intake side of the wind tunnel main body 6 is covered with a plurality of rectifying nets 16, and the condenser nozzle 1 is connected to the wind tunnel main body G side.
7f: Form. In addition, a reinforcing tube 18 is fitted on the outer surface of the inlet nozzle 7.An anemometer sensor 20 suspended from the bottom 1'lK is attached to the first wind speed measurement section 8 of the wind tunnel main body 6. A trap is placed on the center line of the wind tunnel main body 6. Sabo)
19 is attached with a frame lK.

In the second wind speed measuring section 9 formed behind the nozzle 10, an anemometer sensor 22 suspended from a support 21, like the first wind speed σ+II constant section 8, is arranged on the center line of the wind tunnel main body 6. . Support 21 on which anemometer sensor 22 is suspended
is attached to frame 1.

The small diameter nozzle 12 fixed on the exhaust side of the wind tunnel main body 6 is useful when setting the third measurement section.

23゜24 is a regular mt net installed inside the wind tunnel main body G,
The rectifying net 23 is installed between the wind speed measuring section 8 and the wind speed measuring section 9, and the rectifying net 24 is installed between the wind speed measuring section 9 and the small diameter nozzle 12.

In addition, in front of the flow rate measuring nozzles 10 and 12 of the wind tunnel main body 6,
&K H1M pressure HXIJJ port 25, 26, 27
, 28 are each connected to a differential pressure gauge (not shown).

Marking lines 29 are marked in red or the like on the left and right outer surfaces of the center line of the wind tunnel main body 6, so that the anemometer sensor 20.2 can be set accurately in the center. Anemometer sensor 20, 2
An anemometer support 30 is erected on the upper surface of the wind tunnel main body 6 on which the anemometer sensor 2 is suspended, and supports the anemometer sensor 20, 21,
An angle setting device 31 is attached to this anemometer support 30.

When the blower 4 is started with this device, an airflow flows through the wind tunnel main body 6, and the amount of light Q is determined by calculating the differential pressure at the differential pressure outlet before and after the nozzle. Claw (-), d: Nozzle diameter (m) y;
Gravitational acceleration (%”), p: Differential pressure before and after the nozzle (KVm
tsur: specific gravity of air jft <, ”?j'rttQ,a
: Nozzle cross-sectional area (ju''): Wind speed at nozzle outlet (
``3's), the flow rate Q is as follows.

From this flow rate Q, find the wind speed of the cross section where the anemometer sensor is installed, and use this wind speed as a reference to calculate the indicated value of the anemometer (
output) to calibrate U.

For example, an anemometer sensor 2o is installed in the first measuring section 8,
When measuring the differential pressure at the second differential pressure outlet, the wind speed at the first measuring section is determined as . Therefore, the indicated value U of the anemometer at that time may be calibrated using this as a reference.

The first wind speed measurement section 8 is determined by the inner diameter of the wind tunnel main body 6, so in the embodiment, it is a low wind speed measurement section of 1 Å or less and up to 0.05λ.

Since the second wind speed measuring section 9 measures the flow rate with a flow rate measuring nozzle of 100 caliber, the wind speed i++ constant section is relatively high from 05% to 10% in the embodiment.

If a third wind speed measuring section (not shown) is provided in the measuring nozzle 12, the flow will be measured at a constant aperture d of the nozzle I2 ((this will become an even higher wind speed measuring section).

Furthermore, the differential pressure outlet can be selected no matter where the anemometer sensor is installed. first differential pressure outlet 25,
In the case of 26, the diameter of the ff1ll measurement nozzle 10 is large, so a small differential pressure can be obtained, and in the case of the second differential pressure outlet 27, 28, the diameter of the flow rate measurement nozzle is small, so a large differential pressure can be obtained even with the same flow rate. The fact that a large differential pressure can be obtained means that the reading becomes easier and the reading can be performed with high accuracy.

Effects of the Invention As described above, the anemometer calibration device according to the present invention includes a wind tunnel main body 6 having a straight tubular shape with the same diameter mounted on a portable frame 1, and a wind speed sensor mounted on the wind tunnel main body 6.

In addition to providing a plurality of wind speed measurement units 8.9 such as
Multiple flows into ffl: 1ll11 constant nozzle l0112
etc. are arranged in descending order of diameter, and multiple wind speed measuring sections 8.9 and flow rate measuring nozzles 10.12 allow calibration over a wide range from low wind speeds to relatively high speeds, and the wind speed measuring sections are the same at all locations. Since it is a cross-section, the influence of blocking effect can be suppressed to a low level, there is no need to replace the nozzle when measuring flow rate, and reading accuracy can be improved with a large differential pressure.

Further, since the size of the device is relatively small, it can be easily manufactured and portable, and can be mass-produced at low manufacturing cost. Furthermore, the wind tunnel main body 6 is made of transparent acrylic resin, and marking lines such as red are attached to the left and right sides of the center line, so that the wind speed sensors 20 and 22 can be set accurately in the center, and the anemometer support 30 An angle setting device 31 is attached so that accurate setting can be performed, and the casters are used as casters 2 with level adjustment so that the level can be easily maintained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing one example of implementing the present invention, and FIG.
The figure is a side view seen from the intake side. In the figure, main symbols 1, frame 4, blower 6 wind tunnel main body 7 artificial nozzle 8 wind speed measuring section (@1) 9 wind speed measuring section (second
) 10, 32 Flow rate measurement nozzle 15 Duct hose 29 Marked line

Claims (3)

[Claims] (1) A straight tube-shaped wind tunnel main body 6 is mounted on a portable frame 1, and a plurality of wind speed measurement units 8, 9, etc. are provided on the wind tunnel main body 6, and a plurality of flow rate measurement nozzles 10, 1 are installed in descending order of diameter.
A duct hose 15 is provided with an inlet nozzle 7 connected to the intake side of the wind tunnel main body 6, and communicates with the blower 4 on the exhaust side.
An anemometer calibration device characterized in that it is connected in series. (2) The anemometer calibration device according to claim 1, characterized in that the wind tunnel main body 6 is made of transparent acrylic resin or the like, and has marked lines in red or the like on the left and right sides of the center line. (3) Claims 1 and 2, characterized in that casters 2 with level adjustment are attached to the lower surface of the four corners of the frame 1.
Anemometer calibration device as described in section.