JP2014077643A - Anemometer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact anemometer device with reduced acoustic noise which enables highly accurate measurement of wind direction and velocity.SOLUTION: An anemometer device 100 includes a housing 4 with a flow channel section 6 for a measured fluid 2 to flow formed therein and a pair of ultrasonic transceiver units 1A and 1B, each mounted at a predetermined tilt angle with respect to the flow channel section 6, and is designed to measure wind direction and velocity of the measured fluid 2 on the basis of propagation time of an ultrasonic wave transceived between the pair of ultrasonic transceiver units 1A and 1B. A pair of separate fixing plates 51 and 52 is provided with a space therebetween along an axial direction of the flow channel section 6 to fix the pair of ultrasonic transceiver units 1A and 1B onto the housing 4. The effect of acoustic noise is reduced by attaching each of the pair of ultrasonic transceivers 1A and 1B to each of the pair of the separate fixing plates 51 and 52 with an anti-vibration member 20 for preventing transmission of vibration therebetween.

Description

  The present invention relates to a wind direction and wind speed measurement device for accurately measuring the wind direction and wind speed under an apparatus or facility that requires air flow monitoring, and in particular, the wind direction and wind speed in an exhaust pipe, a clean room, a server room, etc. of a semiconductor manufacturing apparatus. The present invention relates to an apparatus suitable for performing measurement.

  As a device for measuring the wind direction and speed of gas, a hot-wire type device described in JP-A-53-43574 (Patent Document 1), JP-A-8-304435 (Patent Document 2), and JP-A-2012- An ultrasonic type described in Japanese Patent No. 103040 (Patent Document 3) is known.

  Among these, the ultrasonic wind direction and wind speed measuring device is characterized in that it can measure zero wind speed in principle and can obtain a linear output with respect to the wind speed, which requires high-precision wind direction and wind speed measurement. It is used in. In addition, by adding sound velocity correction means for removing the effects of changes in sound velocity due to temperature changes to this ultrasonic wind direction and wind velocity measuring device, the wind velocity is highly accurate regardless of the operating environment and gas temperature. Can be measured.

  As for the measurement method of the ultrasonic wind direction and wind speed measuring device, a measurement called “Z method (see FIG. 3)” in which a pair of ultrasonic transmission / reception units are arranged so as to face each other with a gas flow channel between them. There are known a method and a measurement method called “V method (see FIG. 4)” in which a pair of ultrasonic transmission / reception units are arranged on one wall side of a flow path unit. Here, an outline of a conventional apparatus will be described by taking as an example an ultrasonic wind direction and wind speed measuring apparatus to which the Z method, which is easy to understand in explaining the principle, is applied.

FIG. 3 is a diagram showing the measurement principle of the ultrasonic wind direction and wind speed measuring device based on the Z method.
The ultrasonic wind direction and wind speed measuring device includes a pair of ultrasonic transmission / reception units 1A and 1B that transmit and receive ultrasonic waves, a flow path unit 6 through which a gas as a measurement target flows, a propagation time measurement circuit (not shown), and the like. Consists of The ultrasonic transmission / reception unit 1A is installed with an inclination of θ with respect to the central axis of the flow path unit 6, and the ultrasonic transmission / reception unit 1A and the ultrasonic transmission / reception unit 1B face each other with the flow path unit 6 therebetween. To be installed.

  Now, when a pulse voltage as shown in FIG. 5A is applied to the ultrasonic transmission / reception unit 1A made of a piezoelectric vibrator, an ultrasonic wave is emitted from the ultrasonic transmission / reception unit 1A into the flow path unit 6 and flows. The ultrasonic wave propagated in the road is received by the ultrasonic transmission / reception unit 1B, and an ultrasonic reception signal as shown in FIG. 5B is obtained.

Here, the propagation time T of the ultrasonic wave when the wind speed is zero is expressed by the following equation (1).
T = L / C (1)
It is represented by However, L is the propagation path length of the ultrasonic wave, and C is the sound speed inherent to the gas flowing in the flow path.

Now, when the gas flows through the flow path portion 6 at the wind speed V1, the propagation time T1 changes as shown in FIG. The ultrasonic wave propagation time T1 at this time is expressed by the following equation (2).
T1 = L / C1 (2)
It is represented by

Here, C1 is the flow velocity of the gas when affected by the wind speed, and the following equation (3)
C1 = C + V1 cos θ (3)
It is represented by

Substituting equation (3) into equation (2) and solving for wind speed V1, the following equation (4)
V1 = L / T1 cos θ−C (4)
Thus, the wind speed V1 can be measured by measuring the ultrasonic propagation time T1. In addition, the sign of V1 at this time indicates the wind direction.

JP-A-53-43574 JP-A-8-304435 (paragraphs [0005] to [0006], FIG. 1) JP 2012-1-3040 A (paragraphs [0023] to [0025], FIG. 1)

  By the way, recently, downsizing of the wind direction and wind speed measuring device has been strongly demanded due to the restrictions on the installation space in various devices and facilities that require airflow monitoring. If the distance between transmitters and receivers (arrangement interval) is set short, acoustic separation becomes difficult, and in some cases, the ultrasonic signal level directly transmitted through the housing is higher than the ultrasonic signal level transmitted through the air. There is a problem that the wind direction and wind speed cannot be measured due to the increase.

  The present invention has been made in view of the above-described problems, and is a compact wind-direction wind speed measuring device capable of measuring the wind direction and wind speed with high accuracy by reducing ultrasonic waves transmitted through the housing. It is intended to provide.

  The invention of claim 1 includes a housing in which a flow path portion through which a fluid to be measured flows is formed, and a pair of ultrasonic transmission / reception sections installed at a predetermined angle with respect to the flow path portion. In a wind direction and wind speed measuring device that measures the wind direction and the wind speed of a fluid to be measured based on the propagation time of ultrasonic waves transmitted and received between ultrasonic transmission / reception units, provided at intervals along the axial direction of the flow path unit. A pair of separated fixing plates for fixing the pair of ultrasonic transmission / reception units to the housing, and a vibration isolating member for preventing transmission of vibration for each of the pair of ultrasonic transmission / reception units The effect of acoustic noise is reduced by attaching to each of the pair of separated fixed plates.

  According to a second aspect of the present invention, in the wind direction and wind speed measuring device according to the first aspect, the ultrasonic transmission / reception unit has a flange projecting outward from the sensor body, and the sensor of the ultrasonic transmission / reception unit is provided on the fixed plate. An attachment hole for fitting with the main body is provided, and the vibration isolating member made of a rubber material is interposed between the lower surface of the flange portion of the ultrasonic transmission / reception unit and the upper surface of the fixing plate, and the pair of ultrasonic waves The transmission / reception unit is held.

  According to a third aspect of the present invention, in the wind direction and wind speed measuring device according to the first or second aspect, the ultrasonic wave is applied to the inner wall surface of the flow path portion on the side opposite to the side where the pair of ultrasonic transmission / reception units are disposed. A reflection member that reflects the light is provided.

  According to a fourth aspect of the present invention, in the wind direction and wind speed measuring device according to any one of the first to third aspects, a rectifying member made of a mesh is provided between the fixed plate and the flow path portion. Features.

  According to the present invention, each of the pair of ultrasonic transmission / reception units installed at a predetermined inclination angle with respect to the central axis of the flow path unit is provided with a gap along the axial direction of the flow path unit. By adopting a configuration in which each of a pair of separated fixed plates is attached via a vibration isolating member, even if the pair of ultrasonic transmission / reception units are arranged close to each other, acoustic noise generated from the ultrasonic transmission / reception units is The ultrasonic transmitter / receiver can reliably detect the ultrasonic waves that have propagated through the fluid under measurement, making it possible to make the entire device compact and to measure the wind direction and wind speed with high accuracy. It becomes.

It is a figure which shows the structure of the wind direction wind speed measuring apparatus of this invention. It is a figure for demonstrating attachment to the housing | casing of the stationary plate holding an ultrasonic transmission / reception part, and is a bottom view along the AA line of FIG. It is a principle figure of the conventional ultrasonic type wind direction wind speed measuring apparatus using Z method. It is a principle figure of the conventional ultrasonic type wind direction wind speed measuring apparatus using V method. It is an example of the drive waveform of an ultrasonic transmission / reception part, the reception waveform at the time of wind speed zero, and the reception waveform at the time of wind speed V1.

Exemplary embodiments of a wind direction and wind speed measuring device according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing a configuration of a wind direction and wind speed measuring apparatus. The wind direction and wind speed measuring device 100 of the present invention uses the V method as a basic configuration so that a sufficient propagation path length of ultrasonic waves can be ensured even when downsized.

  The wind direction and wind speed measuring device 100 includes a housing 4 having a flow path section 6 through which a fluid 2 to be measured 2 flows, a pair of ultrasonic transmission / reception sections 1A and 1B disposed above the flow path section 6, an ultrasonic transmission / reception section 1A, 2 fixed plates 51 and 52 for holding 1B, a pulse generator 7, a switching SW 8, an amplifier circuit 9, and an electronic circuit unit comprising a time measuring circuit 10, and a reflector 13 provided on the inner wall surface of the flow channel unit 6 Etc.

  The ultrasonic transmission / reception units 1A and 1B have a flange 11 projecting outward from the upper part of the sensor body. In addition, as shown in FIG. 2, mounting holes 51 a and 52 a that are fitted to the sensor main bodies of the ultrasonic transmission / reception units 1 </ b> A and 1 </ b> B are provided in the rectangular fixed plates 51 and 52. Reference numeral 20 denotes a vibration isolating member made of a rubber material for preventing transmission of vibration, and is provided with a hole through which the sensor main body of the ultrasonic transmission / reception units 1A and 1B penetrates like the fixing plates 51 and 52.

  After the sensor body of the ultrasonic transmission / reception parts 1A and 1B is fitted into the hole of the vibration isolating member 20, it is inserted into the mounting holes of the fixing plates 51 and 52, and the two flanges 11 of the ultrasonic transmission / reception parts 1A and 1B are screwed. 12 is fixed to the fixing plates 51 and 52. The vibration isolating member 20 inserted between the lower surface of the flange 11 of the ultrasonic transmission / reception units 1A and 1B and the upper surface of the fixed plates 51 and 52 is compressed and deformed, and the ultrasonic transmission / reception units 1A and 1B are held on the fixed plate. Fixed.

  The fixing plates 51 and 52 that hold the ultrasonic transmission / reception units 1 </ b> A and 1 </ b> B are supported at one end edge by guide grooves 41 provided on both side walls of the housing 4, and with respect to the central axis of the flow path unit 6 Are fixed to the housing 4 with a predetermined inclination angle θ. The fixed plates 51 and 52 are kept at a slight distance along the axial direction of the flow path portion 6 so that the other edges of the fixed plates 51 and 52 do not contact each other when attached to the housing 4. Arranged.

  By fixing the two fixing plates 51 and 52 to the housing 4 in this way, the ultrasonic wave emitted from one ultrasonic transmission / reception unit 1A (1B) is connected to the side where the ultrasonic transmission / reception unit is installed. The light is reflected by the reflection plate 13 having a high reflectivity embedded in the central portion of the channel portion 6 on the opposite side, and is received by the other ultrasonic transmission / reception unit 1B (1A).

  Reference numeral 21 denotes a rectifying member made of a mesh installed between the fixed plates 51 and 52 and the flow path section 6. The rectifying member 21 is provided from the inlet to the outlet of the flow path section 6 so that the flow of the fluid to be measured that passes through the flow path section 6 is not disturbed.

  Reference numeral 43 denotes a partition wall provided above the fixed plates 51 and 52, and forms a storage space for the electronic circuit section described above. In this storage space, the electronic circuit unit including the pulse generator 7, the switching SW 8, the amplifier circuit 9, the time measurement circuit 10, and the like is stored, and then the packing 14 is attached to the upper end of the side wall of the housing 4. By closing, the inside of the storage space is made airtight.

  According to the wind direction and wind velocity measuring apparatus 100 configured as described above, the pair of ultrasonic transmission / reception units 1A and 1B is passed through the vibration isolating member 20 for preventing transmission of vibrations in the axial direction of the flow path unit 6. Are attached to each of a pair of separated fixed plates 51 and 52 that are spaced apart from each other, even if the pair of ultrasonic transmission / reception units 1A and 1B are brought close to each other, The acoustic noise generated from the transmission / reception units 1A and 1B is not transmitted to the housing 4 via the fixed plates 51 and 52, and the ultrasonic transmission / reception units 1A and 1B reliably detect the ultrasonic waves that have propagated through the fluid 2 to be measured. Therefore, it is possible to reduce the size of the apparatus in the fluid flow direction to reduce the size, and to measure the wind direction and the wind speed with high accuracy.

Next, the operation of the wind direction and wind speed measuring apparatus 100 will be described.
First, when a transmission pulse voltage output from the pulse generator 7 is applied to one ultrasonic transmission / reception unit 1A via the switch SW8, ultrasonic waves are emitted toward the inside of the flow path unit 6. Immediately thereafter, the switch SW8 is switched to the ultrasonic transmission / reception unit 1B side, and the ultrasonic wave reflected by the reflecting plate 13 is received by the ultrasonic transmission / reception unit 1B and converted into an electrical signal.

  The ultrasonic reception signal is amplified by the amplification circuit 9 and then input to the time measurement circuit 10. The ultrasonic wave emitted from the ultrasonic transmission / reception unit 1A by the time measurement circuit 10 is propagated until reaching the ultrasonic transmission / reception unit 1B. Time is measured. Subsequently, by the switching operation of the switch SW8, the ultrasonic transmission / reception unit 1B is switched to the transmission side, and the ultrasonic transmission / reception unit 1A is switched to the reception side, and the ultrasonic propagation time is similarly measured.

  Then, the time measuring circuit 10 uses the following equation (5) based on the difference between the ultrasonic propagation time in the same direction (forward direction) and the ultrasonic propagation time in the reverse direction as the flow of the fluid 2 to be measured. Perform the operation.

^{_{V = C 2 (t 2 -t}} 1) / 2Dtanθ ··· (5)
Where D: inner diameter of the flow path portion, C: sound velocity specific to the fluid to be measured flowing in the flow path,
t ₁ : Ultrasonic propagation time in the forward direction, t ₂ : Ultrasonic propagation time in the reverse direction.

  The above arithmetic expression is the same as that of a wind direction and wind speed measuring apparatus to which a conventionally known V method is applied, and therefore the description thereof is omitted.

DESCRIPTION OF SYMBOLS 1A, 1B: Ultrasonic wave transmission / reception part, 11: Flange 2: Fluid to be measured 4: Case 51, 52: Fixed plate 6: Flow path part 7: Pulse generator 8: Switch SW
9: Amplifier circuit 10: Time measuring circuit 13: Reflector 20: Anti-vibration member 21: Rectifying member

Claims (4)

A housing in which a flow path section through which a fluid to be measured flows is formed, and a pair of ultrasonic transmission / reception sections installed at a predetermined inclination angle with respect to the flow path section, between the pair of ultrasonic transmission / reception sections In the wind direction and wind speed measuring device that measures the wind direction and wind speed of the fluid to be measured based on the propagation time of the ultrasonic waves transmitted and received at
Provided with a pair of separated fixing plates that are provided at intervals along the axial direction of the flow path section and fix the pair of ultrasonic transmission / reception sections to the housing;
The influence of acoustic noise is reduced by attaching each of the pair of ultrasonic transmission / reception units to each of the pair of separated fixed plates via a vibration isolating member for preventing transmission of vibration. The wind direction and wind speed measuring device. In the wind direction wind speed measuring device according to claim 1,
The ultrasonic transmission / reception unit has a flange projecting outward from the sensor body,
The fixing plate is provided with a mounting hole for fitting with the sensor body of the ultrasonic transmission / reception unit,
The vibration isolating member made of a rubber material is interposed between the lower surface of the flange portion of the ultrasonic transmission / reception unit and the upper surface of the fixing plate, and the pair of ultrasonic transmission / reception units is held. Wind direction and wind speed measuring device.   3. The wind direction and wind speed measuring device according to claim 1, wherein a reflection member that reflects ultrasonic waves is provided on an inner wall surface of the flow path portion opposite to a side where the pair of ultrasonic transmission / reception units are disposed. A wind direction and wind speed measuring device characterized by that. 4. The wind direction and wind speed measuring device according to claim 1, wherein a rectifying member made of a mesh is provided between the fixed plate and the flow path portion. 5. .