close

Вход

Забыли?

вход по аккаунту

JP2009008406

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2009008406
An object of the present invention is to provide an ultrasonic flowmeter and an ultrasonic
transducer unit capable of performing flow rate measurement with high accuracy. According to
an ultrasonic flowmeter (10) of the present invention, a noise canceling ultrasonic transducer
(30) fixed to the same transmitter / receiver fixed wall (18) as the transmitting ultrasonic
transducer (20) for measurement is used. Since the measurement ultrasonic transducer 20 on the
transmission side transmits ultrasonic waves in reverse phase to the ultrasonic waves to be
transmitted, the measurement ultrasonic transducer 20 on the transmission side to the
transducer fixed wall 18 The ultrasonic waves propagating to it are canceled (cancelled). That is,
the ultrasonic wave (so-called case noise) propagating to the measurement housing 11 through
the transmitter / receiver fixed wall 18 is reduced or eliminated along with the transmission of
the ultrasonic wave from the ultrasonic transducer 20 for measurement. be able to. Thus, flow
rate measurement can be performed with high accuracy. [Selected figure] Figure 1
Ultrasonic flowmeter and ultrasonic transducer unit
[0001]
The present invention propagates ultrasonic waves transmitted and received between a pair of
measurement ultrasonic transducers to the fluid flowing in the flow path of the measurement
housing, and measures the flow rate of the fluid based on the propagation time The present
invention relates to an ultrasonic flowmeter and an ultrasonic transducer unit attached to the
ultrasonic flowmeter.
[0002]
04-05-2019
1
As a conventional ultrasonic flow meter of this type, by fixing a pair of ultrasonic transducers to
a measuring tube via a rubber vibration isolation member, the ultrasonic transducer can be
connected to the tube wall of the measuring tube. What reduced ultrasonic waves (so-called, case
noise) to propagate is known (for example, refer to patent documents 1 and 2).
JP-A-61-25021 (page 4, line 7 to page 5, line 6, FIG. 1) JP-A-11-23332 (paragraphs [0008],
[0009], FIG. 2)
[0003]
However, in the above-described conventional ultrasonic flow meter, when the temperature is
lowered and the rubber is cured, there is a problem that the housing noise can not be sufficiently
reduced and the measurement accuracy is deteriorated.
[0004]
The present invention has been made in view of the above-described circumstances, and an
object thereof is to provide an ultrasonic flowmeter and an ultrasonic transducer unit capable of
performing flow rate measurement with high accuracy.
[0005]
The ultrasonic flowmeter according to the invention of claim 1 made to achieve the above object
is characterized in that the measurement housing having a flow path through which the fluid
flows is divided into an upstream side and a downstream side of the flow path, and a pair of
transmission and reception is performed. A wave detector fixed wall is provided, and a pair of
measurement ultrasonic transducers is fixed to the mutually facing surface of the pair of
transducer fixed walls, and transmission and reception is performed between the pair of
measurement ultrasonic transducers. In an ultrasonic flow meter that propagates a waved
ultrasonic wave to a fluid in a flow channel and measures the flow rate of the fluid based on the
propagation time, a pair of transducer fixed walls opposite to each other are opposed to each
other. The ultrasonic wave is transmitted to the transducer fixed wall by transmitting ultrasonic
waves of the opposite phase to the ultrasonic wave transmitted by the ultrasonic wave for
measurement. Featuring a pair of noise-canceling ultrasonic transducers for canceling acoustic
waves To.
[0006]
According to the invention of claim 2, in the ultrasonic flowmeter according to claim 1, the noise
04-05-2019
2
canceling ultrasonic transducer is configured to be capable of receiving ultrasonic waves
propagating to the transducer fixed wall, and for measuring Ultrasonic wave receiver for
measurement that the ultrasonic wave transmitter-receiver receives and outputs ultrasonic
waves, and ultrasonic wave transmission / reception for noise cancellation fixed to the same
transmitter / receiver fixed wall as the ultrasonic wave transmitter-receiver for measurement on
the reception side Of the measurement reception signals based on the noise cancellation
reception signal that the wave receiver receives and outputs an ultrasonic wave, the ultrasonic
wave received by the measurement ultrasonic transmitter / receiver via the transmitter / receiver
fixed wall. This embodiment is characterized in that a reception signal processing unit that
cancels the reception noise component by the sound wave is provided.
[0007]
The invention of claim 3 is the ultrasonic flowmeter according to claim 1 or 2, wherein the
ultrasonic transducer for measurement and the ultrasonic transducer for noise cancellation have
the same structure and the same size of ultrasonic transducer. It is characterized in that it is a
bowl.
[0008]
The invention according to claim 4 relates to the ultrasonic flowmeter according to any one of
claims 1 to 3, wherein the measuring housing has a linearly extending tubular structure and a
fluid inflow portion and a fluid on the side near the both ends. A measurement pipe having an
outflow portion and a pair of end closing walls closing the both ends of the measurement pipe
are provided, and a pair of transducer fixed walls are formed by the fluid inflow portion and the
end of the measurement pipe. It is characterized in that it is disposed between the partially
closed wall and between the fluid outlet and the end closed wall and fixed to the inside of the
measuring tube.
[0009]
The invention according to claim 5 is the ultrasonic flowmeter according to claim 4, wherein the
pair of transducer fixed walls are formed in a flat plate shape, and the transducer fixed wall and
the end closed wall are provided at both ends of the measurement tube portion. A pair of end
partition areas sandwiched between the pair of transducer fixed walls, and an area between the
pair of transducer fixed walls of the measuring tube section, and a pair of ends It is characterized
in that it has a communication passage communicating with the partial partition area.
[0010]
In the ultrasonic flowmeter according to the invention of claim 6, the measurement housing
04-05-2019
3
having the flow path through which the fluid flows is divided into the upstream side and the
downstream side of the flow path to provide a pair of transducer fixed walls, and A pair of
measurement ultrasonic transducers is fixed to the opposing surfaces of the pair of transducer
fixed walls, and ultrasonic waves transmitted and received between the pair of measurement
ultrasonic transducers are in the flow path. In the ultrasonic flowmeter, which propagates to the
fluid of the fluid and measures the flow rate of the fluid based on the propagation time, the fluid
is fixed to the opposite surface of the pair of transducer fixed walls opposite to each other A pair
of receiving noise cancellation for receiving the ultrasonic wave propagating to the transmitter
fixed wall when the ultrasonic transmitter / receiver receives the ultrasonic wave from the
measuring ultrasonic transmitter / receiver on the other side An ultrasonic transducer for
measurement, and a received wave signal for measurement which the ultrasonic transducer for
measurement receives and outputs an ultrasonic wave; And a noise cancel reception signal that is
received and output from the same ultrasonic wave receiver for reception noise cancellation fixed
to the same transmitter / receiver fixed wall as the measurement ultrasonic transducer on the
reception side of the A receiving signal processing unit for canceling the receiving noise
component by the ultrasonic wave received by the measuring ultrasonic transducer among the
measurement receiving signals based on the above. It is characterized by
[0011]
The ultrasonic transducer unit according to the invention of claim 7 is attached in a pair to the
measurement housing having a flow path through which fluid flows in the ultrasonic flow meter,
and the ultrasonic wave is transmitted and received to generate the flow rate of the fluid. An
ultrasonic transducer unit used for measurement, comprising: a transducer fixed wall whose
outer edge is fixed to the measurement housing; and an outer surface of the transducer fixed wall
fixed to the front side surface of the fluid flowing in the flow path An ultrasonic transducer for
measurement capable of transmitting ultrasonic waves, and an ultrasonic wave of the opposite
phase to ultrasonic waves transmitted by the ultrasonic transducer for measurement being fixed
to the back side of the fixed wall of the transmitter / receiver and fixed to the transmitter fixed
wall. The present invention is characterized in that it has a noise canceling ultrasonic transducer
for canceling ultrasonic waves propagating from the measuring ultrasonic transducer to the
transducer fixed wall.
[0012]
The ultrasonic transducer unit according to the invention of claim 8 is attached in a pair to the
measurement housing having a flow path through which fluid flows in the ultrasonic flow meter,
and the ultrasonic wave is transmitted and received to generate the flow rate of the fluid. An
ultrasonic transducer unit used for measurement, comprising: a transducer fixed wall whose
outer edge is fixed to the measurement housing; and a front side surface of the transducer fixed
wall for propagating the fluid in the flow path An ultrasonic transducer for measurement capable
04-05-2019
4
of receiving ultrasonic waves, and a measurement-use ultrasonic transducer fixed to the back
surface of the fixed wall of the transmitter-receiver, when the ultrasonic transducer for
measurement receives ultrasonic waves, the transmitter-receiver is fixed The ultrasonic wave
received by the ultrasonic wave received through the transmitter / receiver fixed wall among the
measurement wave receiving signals which the ultrasonic wave transmitted to the wall is
received and the ultrasonic wave for measurement receives and outputs the ultrasonic wave And
an ultrasonic transducer for receiving noise cancellation for detecting a receiving noise
component Furnace has a feature.
[0013]
[Inventions of Claims 1 and 7] According to the inventions of claims 1 and 7 configured as
described above, when ultrasonic waves are transmitted and received between a pair of
measurement ultrasonic transducers, transmission is performed. The noise cancellation
ultrasonic transducer fixed to the same transducer fixed wall as the ultrasonic transducer for
measurement on the wave side is the reverse of the ultrasonic wave transmitted by the ultrasonic
transducer for measurement on the transmission side. Since the ultrasonic waves of the phase
are transmitted, the ultrasonic waves propagating from the measuring ultrasonic transducer to
the transducer fixed wall are canceled (cancelled).
That is, with the transmission of ultrasonic waves from the ultrasonic transducer for
measurement, it is possible to reduce or eliminate the ultrasonic wave (so-called case noise)
propagating to the measurement housing through the transmitter / receiver fixed wall. .
Thus, flow rate measurement can be performed with high accuracy.
[0014]
[Invention of Claim 2] According to the invention of claim 2, when the ultrasonic wave
propagates through the measurement housing and the transmitter-receiver fixed wall, the
ultrasonic transducer for measurement on the reception side is in the fluid. Both the propagated
ultrasonic waves and the ultrasonic waves propagated through the measurement housing and the
transducer fixed wall are received.
04-05-2019
5
Also, the noise cancellation ultrasonic transducer fixed to the same transducer fixed wall as the
measurement ultrasonic transducer on the receiving side receives only the ultrasonic wave that
has propagated through the measurement housing and transducer fixed wall. To wave.
Then, measurement is performed based on the measurement reception signal that the
measurement ultrasonic transducer receives and outputs, and the noise cancellation reception
signal that the noise cancellation ultrasonic transducer receives and outputs. Among the received
wave signals, since the reception noise component (that is, the case noise) received by the
measurement ultrasonic transducer via the transmitter / receiver fixed wall in the measurement
receive signal is canceled, temporarily for measurement on the transmission side. Even if the
ultrasonic wave propagating from the ultrasonic transducer to the measurement housing through
the transducer fixed wall can not be sufficiently reduced, the influence can be eliminated and the
flow rate measurement can be performed with high accuracy.
[0015]
[Invention of Claim 3] According to the invention of Claim 3, since the ultrasonic transducer for
measurement and the ultrasonic transducer for noise cancellation can be constituted by a
common ultrasonic transducer, the parts It is possible to reduce the time for procurement and
parts management.
[0016]
[Invention of Claim 4] According to the invention of Claim 4, in the ultrasonic transducer for
noise cancellation, the side and the transmission / reception wavefront of the ultrasonic wave are
covered by the measurement tube portion and the end portion closing wall, Unnecessary
ultrasonic waves from the outside of the measurement housing can be prevented from being
received.
[0017]
[Invention of Claim 5] According to the invention of Claim 5, the fluid flowing from the fluid
inflow portion flows in the region between the pair of transducer fixed walls in the measurement
tube portion, and the pair of In the end section area, a noise cancellation ultrasonic transducer is
accommodated.
Then, a part of the fluid flowing through the measuring pipe portion flows into the pair of end
04-05-2019
6
section areas through the communication path, so under the same conditions as the measuring
ultrasonic transducer, the noise canceling ultrasonic transducer Can transmit and receive
ultrasonic waves.
[0018]
[Inventions of Claims 6 and 8] According to the inventions of claims 6 and 8 configured as
described above, when ultrasonic waves are transmitted and received between a pair of
measurement ultrasonic transducers, reception is performed. The measurement ultrasonic
transducer on the wave side receives the ultrasonic wave propagated in the fluid and the
ultrasonic wave propagated in the measurement housing and the transducer fixed wall.
Also, the receiving / noise-canceling ultrasonic transducer fixed to the same transducer fixed wall
as the measuring ultrasonic transducer on the receiving side is only the ultrasonic wave that has
propagated through the measuring housing and the transducer fixed wall. Receive
Then, of the received wave signals for measurement received by the ultrasonic transducer for
measurement based on the ultrasonic waves received by the ultrasonic wave receiver for
receiving noise cancellation, the transmitter-receiver fixed wall Since the reception noise
component (so-called case noise) due to the ultrasonic wave received through the above is
canceled, the flow rate measurement can be performed with high accuracy.
[0019]
First Embodiment Hereinafter, a first embodiment of the present invention will be described
based on FIGS. 1 to 4.
Reference numeral 11 in FIG. 1 is a measurement housing in the ultrasonic flowmeter 10 (see
FIG. 2), which is attached at a midway of a feed pipe through which fluid (for example, gas) flows.
[0020]
04-05-2019
7
The measurement housing 11 is provided with a linear measurement pipe portion 12 closed at
both ends by a pair of end closing walls 15, 15, and a flow path 12A through which fluid flows is
formed inside the measurement pipe portion 12 There is.
The flow passage 12A is constituted by large diameter portions 13 and 13 provided at both end
portions in the longitudinal direction and a small diameter portion 14 reduced in a stepped shape
with respect to the large diameter portions 13 and 13, and the small diameter portion The inner
diameter of 14 is constant.
[0021]
The two cylindrical portions 19 and 19 are erected at right angles to the longitudinal direction
from positions near both ends in the longitudinal direction of the measuring tube portion 12.
The inner region of one of the cylindrical portions 19 and 19 (the cylindrical portion 19 on the
right side in FIG. 1) is a fluid inflow path 19A for introducing a fluid into the flow path 12A and
one of the flow paths 12A. It communicates with the large diameter portion 13 of the
The inner region of the other cylindrical portion 19 (the cylindrical portion 19 on the left side in
FIG. 1) is a fluid outflow path 19B for discharging the fluid that has passed through the flow path
12A, and communicates with the other large diameter portion 13. doing.
Then, when a feed pipe (not shown) is connected to both the cylindrical portions 19 and 19, as
shown by the arrows in FIG. 1, from one end side to the other end side of the flow path 12A in
the longitudinal direction (left and right direction in FIG. The fluid flows toward you. In addition,
one cylindrical part 19 corresponds to the "fluid inflow part" of this invention, and the other
cylindrical part 19 corresponds to the "fluid outflow part" of this invention.
[0022]
The ultrasonic transducer units 60, 60 according to the invention of claim 7 of the present
application are fixed inside the large diameter portions 13, 13 of the flow path 12A. The
04-05-2019
8
ultrasonic transducer units 60, 60 are the ultrasonic wave transducer 20 for measurement and
the ultrasonic transducer for noise cancellation on the transducer fixed plate 18 (corresponding
to the "transmitter fixed wall" of the present invention). 30 will be fixed back to back.
[0023]
The transducer fixing plate 18 of the ultrasonic transducer unit 60 has a disk shape having a
diameter larger than the inner diameter of the large diameter portion 13 and having both flat
surfaces in the plate thickness direction. And, on the inner peripheral surface of the large
diameter portion 13, 13, an annular member formed so as to be recessed closer to both ends
(end closed walls 15, 15) of the measurement tube portion 12 than the inner openings of both
cylindrical portions 19, 19 The outer peripheral edge portions of the respective transducer fixing
plates 18, 18 are fitted in the fitting grooves 17, 17.
[0024]
The ultrasonic transducers 20 for measurement are respectively provided on the facing surfaces
18A and 18A (corresponding to the front side surface in claim 7 of the present application)
of the transducer fixing plates 18 and 18 facing each other across the flow path 12A. , 20 are
fixed. The measuring ultrasonic transducers 20, 20 are disposed on the axis of the flow path 12A,
and have a flat cylindrical structure as a whole. In detail, the front end portion of the
measurement ultrasonic transducer 20 has a truncated cone shape, and the front end surface is a
transmission / reception wavefront 20A of ultrasonic waves.
[0025]
Surfaces 18B and 18B on the opposite side to the opposing surfaces 18A and 18A to which the
ultrasonic transducers 20 and 20 for measurement are fixed among the transducer fixing plates
18 and 18 (corresponding to "back side" in claim 7 of the present application In this case, the
noise canceling ultrasonic transducers 30, 30 having the same structure and the same size as the
measuring ultrasonic transducers 20, 20 are fixed. That is, the noise canceling ultrasonic
transducer 30 is fixed back to back with the measuring ultrasonic transducer 20 with the
transducer fixing plate 18 interposed therebetween, whereby the measuring ultrasonic
transducers 20, 20 And the noise cancellation ultrasonic transducers 30 and 30 are arranged
side by side on the axis of the flow path 12A.
04-05-2019
9
[0026]
Further, in the measurement tube portion 12, between the transducer fixing plates 18, 18 and
the end closing walls 15, 15, the flow path 12A is disconnected and closed by the transducer
fixing plates 18, 18. End section areas 16, 16 are formed, and the noise canceling ultrasonic
transducers 30, 30 fixed to the respective transducer fixing plates 18, 18 are accommodated
therein. By accommodating the noise canceling ultrasonic transducers 30, 30 in the end section
regions 16, the noise canceling ultrasonic transducers 30, 30 receive unnecessary ultrasonic
waves from the outside of the measurement housing 11. Receiving waves is prevented.
[0027]
In the end section areas 16, 16, the same fluid (a gas in the present embodiment) as the fluid (the
fluid whose flow rate is to be measured) flowing in the flow path 12A is sealed.
[0028]
As shown in FIG. 2, the measurement ultrasonic transducers 20, 20 are controlled by the
switching signal from the transmission / reception switching unit 41, and when one is connected
to the transmission drive circuit 42 and becomes a transmitter, the other is received It is
connected to the detection circuit 43 to be a receiver, and the transmitter and the receiver are
switched at a predetermined timing.
[0029]
When the transmission drive circuit 42 receives a transmission command from the calculation
unit 45, the transmission drive circuit 42 excites the measurement ultrasonic transducer 20 on
the transmission side to transmit ultrasonic waves.
Specifically, as shown in FIG. 3, a drive pulse is generated by the drive wave generator 42A, and
ultrasonic waves are transmitted from the ultrasonic transducer 20 for measurement by the drive
pulse.
[0030]
04-05-2019
10
The reception detection circuit 43 detects the time measurement unit 44 when the measurement
reception signal output by the measurement ultrasonic transducer 20 on the reception side
receives and outputs an ultrasonic wave reaches a predetermined value. Output a signal.
[0031]
The time measurement unit 44 causes the measurement ultrasonic transducer 20 on the
transmission side to transmit an ultrasonic wave, and the measurement ultrasonic transducer 20
on the reception side to propagate the soot that receives the ultrasonic wave. Measure time
Specifically, the timer of the time measurement unit 44 starts when a transmission instruction is
output from the operation unit 45 to the transmission drive circuit 42, and the timer stops when
a detection signal is input from the reception detection circuit 43. .
[0032]
The calculating unit 45 takes in the propagation time of the ultrasonic wave measured by the
time measuring unit 44.
Then, the propagation time when the ultrasonic wave is transmitted and received from one of the
pair of measurement ultrasonic transducers 20 and 20 toward the other and the propagation
time when the ultrasonic wave is transmitted and received from the other to the other The flow
velocity and the flow rate of the fluid are calculated by the well-known arithmetic equation based
on the difference between For example, the flow velocity and flow rate are calculated based on
the principle that the difference in reciprocal of the propagation time is proportional to the flow
velocity.
[0033]
Now, in the ultrasonic flowmeter 10 of the present invention, not only the ultrasonic transducers
for measurement 20 and 20 but also the ultrasonic transducers for noise cancellation 30 and 30
are controlled by the signal from the transmission / reception switching unit 41. Specifically,
when one measurement ultrasonic transducer 20 is connected to the transmission drive circuit
04-05-2019
11
42, the one measurement ultrasonic transducer 20 is fixed to the same transducer fixing plate 18
as the one measurement ultrasonic transducer 20. The noise cancellation ultrasonic transducer
30 is also connected to the transmission drive circuit 42. At this time, the other measurement
ultrasonic transducer 20 on the receiving side is connected to the reception detection circuit 43,
but is fixed to the same transducer fixing plate 18 as the measurement ultrasonic transducer 20.
The other noise cancellation ultrasonic transducer 30 is not connected to either the transmission
drive circuit 42 or the reception detection circuit 43.
[0034]
Then, when the measurement ultrasonic transducer 20 on the transmission side transmits
ultrasonic waves, the noise cancellation ultrasonic wave transmission / reception fixed to the
same transmitter / receiver fixed plate 18 as the measurement ultrasonic transducer 20 The
ultrasonic wave of the opposite phase to the ultrasonic wave transmitted by the ultrasonic
transducer 20 for measurement is transmitted from the unit 30 (see FIG. 3).
[0035]
Here, when the ultrasonic transducer for measurement 20 transmits ultrasonic waves, the
ultrasonic transducer for measurement 20 to the transducer fixed plate 18 has, for example, a
waveform shown in FIG. Ultrasonic waves propagate.
[0036]
On the other hand, when the noise cancellation ultrasonic transducer 30 fixed to the same
transmitter / receiver fixed plate 18 as the measurement ultrasonic transducer 20 on the
transmission side transmits ultrasonic waves, the noise cancellation super wave is transmitted.
For example, an ultrasonic wave having a waveform shown in FIG. 4B propagates from the
acoustic transducer 30 to the transducer fixing plate 18.
That is, ultrasonic waves having opposite phases propagate from the ultrasonic transducer for
measurement 20 and the ultrasonic transducer for noise cancellation 30 to the transducer fixed
plate 18.
[0037]
As a result, the ultrasonic wave propagated from the ultrasonic transducer 20 for measurement
on the transmission side to the transducer fixed plate 18 is fixed to the same transducer fixed
04-05-2019
12
plate 18 as the ultrasonic transducer 20 for measurement. The noise can be canceled (canceled)
by the ultrasonic wave propagating from the noise cancellation ultrasonic transducer 30 to the
transducer fixing plate 18.
[0038]
The same applies to the case where an ultrasonic wave is transmitted from the other
measurement ultrasonic transducer 20 toward the one measurement ultrasonic transducer 20,
and the other measurement ultrasonic transducer The noise canceling ultrasonic transducer 30
fixed to the same transducer fixing plate 18 as 20 transmits an ultrasonic wave in reverse phase
to the ultrasonic wave transmitted by the measuring ultrasonic transducer 20.
[0039]
Thus, according to the present embodiment, when ultrasonic waves are transmitted and received
between the pair of measurement ultrasonic transducers 20, 20, the same as the measurement
ultrasonic transducer 20 on the transmission side. Because the noise cancellation ultrasonic
transducer 30 fixed to the transducer fixed plate 18 transmits ultrasonic waves in reverse phase
to the ultrasonic waves transmitted by the measurement ultrasonic transducer 20 on the
transmission side. The ultrasonic waves propagating from the transmitting ultrasonic transducer
20 on the transmission side to the transmitter fixed plate 18 are canceled (cancelled).
That is, the ultrasonic wave (so-called case noise) propagating to the measurement housing 11
through the transmitter / receiver fixed plate 18 is reduced or eliminated along with the
transmission of the ultrasonic wave from the ultrasonic transducer 20 for measurement. be able
to.
Thus, flow rate measurement can be performed with high accuracy.
In addition, since the end plates 16 and 16 and the flow path 12A are disconnected by making
the transducer fixing plates 18 and 18 flat, it is transmitted from the noise canceling ultrasonic
transducers 30 and 30. It is possible to prevent the ultrasonic waves reflected by the end closing
walls 15, 15 from entering the flow path 12A.
[0040]
04-05-2019
13
Second Embodiment In the second embodiment, the connection state between the noise
cancellation ultrasonic transducers 30 and 30 and the transmission drive circuit 42 and the
reception detection circuit 43 when transmitting and receiving ultrasonic waves, and reception
detection The processing in the circuit 43 is different from that of the first embodiment.
Hereinafter, only the configuration different from that of the first embodiment will be described,
and the other configurations are the same as those of the above-described first embodiment.
[0041]
As shown in FIG. 5, the transmission / reception switching unit 41 is the same as the
measurement-use ultrasonic transducer 20 on the reception side when transmitting and
receiving ultrasonic waves between a pair of measurement ultrasonic transducers 20. The noise
cancellation ultrasonic transducer 30 fixed to the transducer fixing plate 18 is connected to the
reception detection circuit 43. At this time, the noise cancellation ultrasonic transducer 30 fixed
to the same transmitter / receiver fixed plate 18 as the measurement ultrasonic transducer 20 on
the transmission side is used as either the transmission drive circuit 42 or the reception
detection circuit 43. Even not connected.
[0042]
The ultrasonic waves transmitted from the measurement ultrasonic transducer 20 propagate the
fluid flowing through the flow path 12A and are received by the measurement ultrasonic
transducer 20 on the receiving side. Also, an ultrasonic wave propagates from the ultrasonic
transducer 20 for measurement on the transmission side to the transducer fixed plate 18, and
this propagates through the measurement housing 11 and the transducer fixed plate 18 for
measurement on the receiving side. The sound wave is received by the sound wave transceiver
20. FIG. 7A shows an example of a measurement reception signal that is received and output by
the measurement ultrasonic transducer 20 on the reception side.
[0043]
On the other hand, in the noise cancellation ultrasonic transducer 30 fixed to the same
transmitter / receiver fixed plate 18 as the measurement ultrasonic transducer 20 on the
04-05-2019
14
reception side, the ultrasonic wave propagated in the fluid is received. Instead, only the
ultrasonic waves propagated through the measurement housing 11 and the transducer fixing
plates 18 and 18 are received. Note that FIG. 7B shows an example of a noise cancellation receive
signal that the noise cancellation ultrasonic transducer 30 receives and outputs.
[0044]
As shown in FIG. 6, in the reception detection circuit 43, the measurement received wave signal
by the measurement ultrasonic wave transmitter-receiver 20 and the noise cancellation wave
received signal by the noise cancellation ultrasonic wave transmitter-receiver 30 are fetched and
The signal is amplified, and the subtractor 43A subtracts the noise cancellation reception signal
from the measurement reception signal. As a result, of the received wave signal for measurement,
the ultrasonic wave transmitter / receiver 20 for measurement cancels the received noise
component due to the ultrasonic wave received via the measurement housing 11 and the
transmitter / receiver fixed plates 18 and 18. FIG. 7C shows an example of the measurement
received wave signal after canceling the received wave noise component.
[0045]
Then, the reception point detection unit 43B determines whether or not the measurement
reception signal after canceling the reception noise component has reached a predetermined
value, and when it is determined that the predetermined value is reached, reception detection is
performed. The circuit 43 outputs a detection signal to the time measuring unit 44. As a result,
the timer of the time measurement unit 44 is stopped, and the propagation time of the ultrasonic
wave propagated in the fluid between the pair of measurement ultrasonic transducers 20 and 20
is measured. The reception detection circuit 43 corresponds to the reception signal processing
unit in the present invention.
[0046]
As described above, according to the present embodiment, when ultrasonic waves are
transmitted and received between the pair of measurement ultrasonic transducers 20 and 20, the
measurement ultrasonic transducer 20 on the reception side is a fluid. The ultrasonic wave
propagated through the inside and the ultrasonic wave propagated through the measurement
housing 11 and the transducer fixing plates 18 and 18 are received. The noise cancellation
04-05-2019
15
ultrasonic transducer 30 fixed to the same transducer fixed plate 18 as the measurement
ultrasonic transducer 20 on the receiving side comprises the measurement housing 11 and the
transducer fixed plates 18 and 18. Receive only the propagated ultrasound. Then, based on the
measurement reception signal that the measurement ultrasonic transducer 20 receives and
outputs, and the noise cancellation reception signal that the noise cancellation ultrasonic
transducer 30 receives and outputs Of the received wave signals for measurement, since the
received wave noise component received by the ultrasonic wave transmitter / receiver 20 for
measurement via the wave transmitter / receiver fixed plate 18 is canceled, the flow rate
measurement can be performed with high accuracy. The noise cancellation ultrasonic
transducers 30 and 30 of the present embodiment correspond to the reception noise
cancellation ultrasonic transducer in claims 6 and 8 of the present invention. Further,
according to the present invention, the ultrasonic transducers for measurement 20 and 20 in the
present embodiment, the ultrasonic transducers for noise cancellation 30 and 30, and the
transducer fixing plates 18 and 18 to which they are fixed are used. An "ultrasonic transducer
unit" according to the invention of claim 8 is configured.
[0047]
Third Embodiment In the third embodiment, the connection state between the noise cancellation
ultrasonic transducers 30 and 30 and the transmission drive circuit 42 and the reception
detection circuit 43 when transmitting and receiving ultrasonic waves, and reception detection
The processing in the circuit 43 is different from that of the first embodiment.
[0048]
Specifically, as shown in FIG. 8, when ultrasonic waves are transmitted and received between a
pair of measurement ultrasonic transducers 20 and 20, the measurement ultrasonic transducer
20 on the receiving side and The noise cancellation ultrasonic transducer 30 fixed to the same
transducer fixing plate 18 is connected to the reception detection circuit 43, and the same
transducer fixing plate as the measuring ultrasonic transducer 20 on the transmission side. The
noise cancellation ultrasonic transducer 30 fixed to 18 is connected to the transmission drive
circuit 42.
[0049]
When the measurement ultrasonic transducer 20 on the transmission side transmits ultrasonic
waves, the measurement ultrasonic transducer 20 transmits the ultrasonic wave to the
transducer fixed plate 18, for example, as shown in FIG. 4A. Ultrasonic waves propagate.
[0050]
04-05-2019
16
On the other hand, when the noise cancellation ultrasonic transducer 30 fixed to the same
transmitter / receiver fixed plate 18 as the measurement ultrasonic transducer 20 on the
transmission side transmits ultrasonic waves, the noise cancellation super wave is transmitted.
For example, an ultrasonic wave having a waveform shown in FIG. 4B propagates from the
acoustic transducer 30 to the transducer fixing plate 18.
That is, ultrasonic waves having opposite phases propagate from the ultrasonic transducer for
measurement 20 and the ultrasonic transducer for noise cancellation 30 to the transducer fixed
plate 18.
[0051]
As a result, the ultrasonic wave transmitted from the transmitting ultrasonic transducer 20 for
measurement to the transducer fixing plate 18 is fixed to the same transducer fixing plate 18 as
the ultrasonic transducer 20 for measuring. The noise can be canceled by the ultrasonic wave
transmitted from the noise cancellation ultrasonic transducer 30 to the transducer fixing plate
18.
Therefore, it is possible to reduce or eliminate the ultrasonic waves (so-called case noise)
propagating through the measurement housing 11 and the transmission / reception fixed plates
18, 18 in response to the transmission of the ultrasonic waves from the measurement ultrasonic
transducer 20. it can.
[0052]
In addition, if the ultrasonic waves (chassis noise) propagating from the ultrasonic transducer for
measurement 20 on the transmission side to the transducer fixing plate 18 can not be
sufficiently reduced by any chance, it is as follows.
[0053]
That is, the ultrasonic transducer 20 for measurement on the receiving side includes both the
ultrasonic wave propagated in the fluid flowing through the flow path 12A and the ultrasonic
04-05-2019
17
wave propagated through the measurement housing 11 and the transducer fixed plates 18 and
18. Receive
Note that FIG. 7A shows an example of a measurement reception signal that is received and
output by the measurement ultrasonic transducer 20 on the transmission side.
On the other hand, in the noise cancellation ultrasonic transducer 30 fixed to the same
transmitter / receiver fixed plate 18 as the measurement ultrasonic transducer 20 on the
reception side, the ultrasonic wave propagated in the fluid is received. Instead, only the
ultrasonic waves propagated through the measurement housing 11 and the transducer fixing
plates 18 and 18 are received. Note that FIG. 7B shows an example of a noise cancellation receive
signal that the noise cancellation ultrasonic transducer 30 receives and outputs.
[0054]
As shown in FIG. 6, in the reception detection circuit 43, the measurement received wave signal
by the measurement ultrasonic wave transmitter-receiver 20 and the noise cancellation wave
received signal by the noise cancellation ultrasonic wave transmitter-receiver 30 are fetched and
The signal is amplified, and the subtractor 43A subtracts the noise cancellation reception signal
from the measurement reception signal. As a result, of the reception signals for measurement,
the reception noise component (reception for noise cancellation) by the ultrasonic waves
received by the measurement ultrasonic transducer 20 via the measurement housing 11 and the
transducer fixing plates 18 and 18. Cancel the wave signal). FIG. 7C shows an example of the
measurement received wave signal after canceling the received wave noise component.
[0055]
Then, the reception point detection unit 43B determines whether or not the measurement
reception signal after canceling the reception noise component has reached a predetermined
value, and when it is determined that the predetermined value is reached, reception detection is
performed. The circuit 43 outputs a detection signal to the time measuring unit 44. As a result,
the timer of the time measurement unit 44 is stopped, and the propagation time of the ultrasonic
wave propagated in the fluid between the pair of measurement ultrasonic transducers 20 and 20
is measured. The reception detection circuit 43 corresponds to the reception signal processing
unit in the present invention.
04-05-2019
18
[0056]
The other configuration is the same as that of the first embodiment, so the same reference
numeral is given to the same configuration, and the overlapping description will be omitted.
[0057]
Thus, according to the present embodiment, when ultrasonic waves are transmitted and received
between the pair of measurement ultrasonic transducers 20, 20, the same as the measurement
ultrasonic transducer 20 on the transmission side. Because the noise cancellation ultrasonic
transducer 30 fixed to the transducer fixed plate 18 transmits ultrasonic waves in reverse phase
to the ultrasonic waves transmitted by the measurement ultrasonic transducer 20 on the
transmission side. The ultrasonic waves propagating from the transmitting ultrasonic transducer
20 on the transmission side to the transmitter fixed plate 18 are canceled (cancelled).
That is, the ultrasonic wave (so-called case noise) propagating to the measurement housing 11
through the transmitter / receiver fixed plate 18 is reduced or eliminated along with the
transmission of the ultrasonic wave from the ultrasonic transducer 20 for measurement. be able
to. Thus, flow rate measurement can be performed with high accuracy.
[0058]
Even if the ultrasonic wave propagating to the measurement housing 11 from the ultrasonic
transducer 20 for measurement on the transmission side through the transducer fixing plate 18
can not be sufficiently reduced, the ultrasonic transducer for measurement A measurement
reception signal (see FIG. 7A) that 20 receives and outputs, and a noise cancellation reception
signal that the noise cancellation ultrasonic transducer 30 receives and outputs (FIG. 7 (B Of the
received wave signal for measurement, cancels the received noise component (that is, the case
noise) received by the ultrasonic transducer 20 for measurement via the transmitter / receiver
fixed plate 18. Therefore, it is possible to measure the flow rate with high accuracy.
[0059]
[Other Embodiments] The present invention is not limited to the above-described embodiments,
and, for example, the embodiments described below are also included in the technical scope of
the present invention, and in addition to the following, the summary Various modifications can
be made without departing from the scope of the invention.
04-05-2019
19
[0060]
(1) As shown in FIG. 9, a communication passage 18C is formed in the both transducer fixing
plates 18 so as to pass through, and the end section areas 16, 16 are communicated with the
flow passage 12A, passing through the flow passage 12A. A portion of the fluid may flow into the
end compartments 16 and 16 from the communication passage 18C.
In this way, the fluid flowing in the flow path 12A flows into the end section regions 16, 16, and
under the same conditions (for example, concentration, pressure, temperature) as the ultrasonic
transducers 20, 20 for measurement. The ultrasonic transducers 30 and 30 for noise
cancellation can transmit and receive ultrasonic waves.
The communication passage 18C may be formed by cutting out a part of the outer edge portion
of the transducer fixing plate 18.
[0061]
(2) The transducer fixing plate 18 and the measurement housing 11 are separate parts, but they
may be integrally formed.
[0062]
(3) As shown in FIG. 10, the measuring tube portion 12 of the measuring housing 11 has a
cylindrical structure with both ends open, and the two openings 12B and 12B (only one opening
12B is shown in FIG. 10) ) By fitting or screwing the cap members 50, 50 separately from the
measuring tube portion 12 together to close both openings 12B, 12B, and the ultrasonic
transducer unit 60, 60 as a measuring housing 11 may be fixed.
More specifically, the cap member 50 includes a cylindrical wall 50A fitted or screwed into the
inside of the opening 12B, and an end closed wall 50B which is closed to one end by closing one
end of the cylindrical wall 50A. After the ultrasonic transducer unit 60 is inserted and fitted from
the opening 12B of the measurement tube 12, the cylinder wall 50A of the cap member 50 is
fitted or screwed inside the opening 12B to transmit and receive the ultrasonic transducer unit
04-05-2019
20
60. The outer edge of the wave fixing plate 18 may be held between the tip of the cylindrical wall
50A and the inner step 12C of the measuring pipe 12. In this case, a seal member (not shown)
seals between the outer peripheral surface of the cylindrical wall 50A and the inner peripheral
surface of the opening 12B or between the end closed wall 50B and the end surface of the
measurement pipe 12 Is preferred.
[0063]
(4) In addition, the fitting groove 17 formed in one of the measurement pipe assembly of the pair
of measurement pipe assemblies formed by dividing the measurement pipe 12 vertically (in a
plane parallel to the axial direction) In this case, the transducer fixing plate 18 of the ultrasonic
transducer unit 60 is fitted, and in this state, the measuring tube constructions are united with
each other to form the ultrasonic transducer unit 60, 60 as a measuring housing. It may be fixed
inside of 11.
[0064]
(5) In the first to third embodiments, the ultrasonic transducers for measurement 20, 20 and the
ultrasonic transducers for noise cancellation 30, 30 are arranged side by side on the axis of the
flow path 12A. However, as shown in FIG. 11, they may be arranged side by side in a direction
obliquely crossing the axis of the flow path 12A.
[0065]
(6) The transducer fixing plates 18 and 18 are fitted on the entire circumference of the inner
peripheral surface of the measurement pipe portion 12, but only a part of the inner peripheral
surface of the measurement pipe portion 12 as shown in FIG. May be fitted.
[0066]
Sectional view of measurement housing of ultrasonic flowmeter according to the first
embodiment of the present invention Block diagram of ultrasonic flowmeter Block diagram of
transmission drive circuit (A) Leakage from the ultrasonic transducer for measurement to the
transmitter fixed wall The waveform of the ultrasonic wave, (B) The waveform of the ultrasonic
wave leaked from the ultrasonic transducer for noise cancellation to the transducer fixed wall
Block diagram of the ultrasonic flowmeter according to the second embodiment Block diagram of
the reception detection circuit ( A) Graph of measurement received signal, (B) Graph of received
signal for noise cancellation, (C) Graph of received signal for measurement after cancellation of
received noise component Ultrasonic flowmeter according to the third embodiment Block
diagram Partial sectional view of measurement housing according to another embodiment (1)
Cross sectional view of measurement housing according to another embodiment (3) Cross
04-05-2019
21
sectional view of measurement housing according to another embodiment (5) 6) of the
measuring tube Rear view
Explanation of sign
[0067]
DESCRIPTION OF SYMBOLS 10 Ultrasonic flowmeter 11 Measurement housing 12 Measurement
pipe part 12A Flow path 15 End block wall 16 End section area 18 Transmitter and receiver
fixed plate (Transmitter receiver fixed wall) 18A Opposite surface (front side) 18B Opposite to
opposite surface Side surface (back side) 19 Cylindrical part (fluid inflow part, fluid outflow part)
20 Ultrasonic transducer for measurement 30 Ultrasonic transducer for noise cancellation
(Ultrasonic transducer for reception noise cancellation) 43 Reception Detection circuit (reception
signal processing unit) 50B End blockade wall 60 Ultrasonic transducer unit
04-05-2019
22
1/--страниц
Пожаловаться на содержимое документа