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DESCRIPTION JP2015052591

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DESCRIPTION JP2015052591
A transducer system with reduced acoustic noise coupling. The transducer system is for
preventing the floating part of the transducer system from contacting a fixed part of the
transducer system, or for reducing the degree to which the floating part contacts the fixed part
due to process pressure or atmospheric pressure. Includes pressure balancing mechanism. One
or more sound attenuating elements, interruption grooves, annular projections, or to reduce
acoustic noise coupling between various parts of the transducer system or between the
transducer system and the flow cell in which the transducer system is mounted Includes a
dampening washer. [Selected figure] Figure 1
トランスデューサシステム
[0001]
The subject matter disclosed herein relates generally to transducer systems in which acoustic
noise coupling is reduced.
[0002]
The use of ultrasound to measure flow has been introduced and established in large numbers
worldwide in chemical plants, petrochemical plants, refineries and the like.
Several ultrasonic flowmeters have been developed, including transit-time based systems made
as a single piece "drop-in" flow cell using a wetted transducer. In such systems, one or more
14-04-2019
1
transmit transducers and one or more receive transducers are directed to the media flowing
through the flow cell. An input voltage is applied to the transmit transducer (transmitter) to
transmit ultrasound into the medium. These waves are received by a receiving transducer
(receiver) and converted to an output voltage. The "time of flight" of the wave is determined by
comparing the time when the input voltage is applied to the time when the output voltage is
received.
[0003]
The time t up required for the ultrasound signal to travel against the flow (ie upstream) is longer
than the time t dn required to travel with the flow (ie downstream). The difference Δt between
the upstream travel time and the downstream travel time is directly proportional to the flow
velocity. The operation of the ultrasonic flowmeter strongly depends on the timing of t up, t dn
and Δt. Conversely, the measurements of t up, t dn and Δt depend on the quality of the received
ultrasound signal, eg the signal to noise ratio (SNR).
[0004]
In general, applying ultrasound technology to gas flow measurement is more difficult than liquid
for various reasons, including very low acoustic impedance, higher Mach number, higher turn
down ratio, and gas flow measurement It involves the larger pressure changes involved. For
example, converting electrical pulses to ultrasonic signals in a 0 psig gas medium via the
piezoelectric crystal of the transducer is very inefficient. As a result, transmission of the acoustic
signal through the gas is very small and requires amplification. The amplification amplifies both
the acoustic signal through the gas and unwanted noise that escapes from the side and back of
the transmit transducer through the solid path (eg, the wall of the flow cell) to the side and back
of the receive transducer. In other words, the acoustic noise emitted from the transmitting
transducer is coupled to the flow cell and finally to the receiving transducer. This noise
(sometimes referred to as "short circuit noise") generally does not provide any useful information
about the flow of the fluid, and thus contributes to the overall noise of the system and reduces
the SNR. A high SNR is required to make accurate and reliable flow measurement.
[0005]
Thus, there is a need for a transducer system in which acoustic noise coupling is reduced.
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[0006]
Disclosed herein is a transducer system having reduced acoustic noise coupling.
In some embodiments, the transducer system is to prevent the floating portion of the transducer
system from contacting the stationary portion of the transducer system, or reduce the degree to
which the floating portion contacts the stationary portion by process pressure or atmospheric
pressure Include a pressure balance mechanism to In some embodiments, the transducer system
comprises one or more to reduce acoustic noise coupling between various components of the
transducer system or between the transducer system and the flow cell in which the transducer
system is mounted. Includes sound attenuating elements, interrupt grooves, annular protrusions,
or damping washers.
[0007]
In some embodiments, the transducer system comprises a transducer head in which the
ultrasound transducer is disposed, a transducer stem extending from the transducer head, and a
transducer system between the transducer system and the housing when the transducer system
is mounted on the housing. And a decoupling mechanism configured to reduce acoustic coupling.
[0008]
In some embodiments, the transducer system includes a transducer head having a first surface
configured to receive process pressure when an ultrasound transducer is disposed and the
transducer system is mounted to the flow cell.
The system also includes a transducer stem coupled to and extending from the transducer head.
The system also includes a pressure mounting assembly in which at least a portion of the
transducer stem is disposed, the pressure mounting assembly being configured to receive a
process pressure when the transducer system is mounted to the flow cell. It has an equilibrium
surface. The first surface and the first pressure balancing surface face in opposite directions such
that the process pressure acting on the first pressure balancing surface offsets the process
pressure acting on the first surface.
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[0009]
In some embodiments, the transducer system comprises a transducer head in which the
ultrasound transducer is disposed, a transducer stem extending from the transducer head, and at
least one acoustic attenuation element disposed outside the transducer stem, the transducer
system comprising: At least one sound attenuating element disposed between the transducer
stem and the flow cell when the system is mounted to the flow cell, and an annular interrupt
groove formed in the transducer stem, the transducer stem having a reduced cross-sectional area
And an annular interrupt groove defining a longitudinal portion of the
[0010]
In some embodiments, the transducer system comprises a transducer head in which the
ultrasound transducer is disposed, a transducer stem extending from the transducer head, a
piston disposed above the transducer stem, and a position between the piston and the transducer
stem A first set of one or more sound attenuating elements disposed and a second set of one or
more sound attenuating elements disposed external to the piston, the transducer system
mounted on the flow cell In some cases, a second set of acoustic damping elements disposed
between the piston and the flow cell, a nut disposed on the transducer stem and configured to
engage the bore of the flow cell, the piston and the nut And a dampening washer disposed
between.
[0011]
These and other features will be more readily understood from the following detailed description
in conjunction with the accompanying drawings.
[0012]
FIG. 1 is a perspective view of an exemplary flow cell that can use the transducer system
disclosed herein.
It is a top view of the flow cell of FIG.
FIG. 7 is a cross-sectional view of an exemplary embodiment of a transducer system.
5 is an exploded perspective view and an assembled perspective view of the transducer system of
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FIG. 3; FIG. 4 is a cross-sectional view of the transducer system of FIG. 3 with hatching indicating
pressure exposure. FIG. 7 is a cross-sectional view of another embodiment of a transducer
system. FIG. 7 is an exploded perspective view and an assembled perspective view of the
transducer system of FIG. 6; FIG. 7 is a cross-sectional view of yet another embodiment of a
transducer system. FIG. 9 is an exploded perspective view and an assembled perspective view of
the transducer system of FIG. 8;
[0013]
It should be noted that the drawings are not necessarily to scale. The drawings are intended to
depict only typical aspects of the inventive subject matter disclosed herein, and therefore should
not be considered as limiting the scope of the present disclosure. In the drawings, similar
symbols in the drawings indicate similar elements.
[0014]
Certain exemplary embodiments will now be described to provide an overall knowledge of the
principles of the structure, function, manufacture, and use of the devices, systems and methods
disclosed herein. One or more examples of these embodiments are illustrated in the
accompanying drawings. As will be appreciated by one skilled in the art, the devices, systems and
methods specifically described herein and illustrated in the accompanying drawings are nonlimiting exemplary embodiments and the scope of the present invention will be claimed. Defined
only by The features illustrated or described in connection with one exemplary embodiment can
be combined with the features of other embodiments. Such modifications and variations are
intended to be included within the scope of the present invention.
[0015]
Disclosed herein is a transducer system having reduced acoustic noise coupling. In some
embodiments, the transducer system is to prevent the floating portion of the transducer system
from contacting the stationary portion of the transducer system, or reduce the degree to which
the floating portion contacts the stationary portion by process pressure or atmospheric pressure
Include a pressure balance mechanism to In some embodiments, the transducer system
comprises one or more to reduce acoustic noise coupling between various components of the
transducer system or between the transducer system and the flow cell in which the transducer
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system is mounted. Includes sound attenuating elements, interrupt grooves, annular protrusions,
or damping washers.
[0016]
1 and 2 show one exemplary embodiment of a flow cell 100 that can use the transducer system
disclosed herein. As shown, flow cell 100 includes the length of pipe 102 that defines a lumen
104 through which the media flows. Flanges 106 are provided at both ends of the flow cell 100
to facilitate installation of the flow cell in a larger flow system. Flow cell 100 also includes a
plurality of bores or ports 108 to which transducer systems of the type described herein may be
attached. The ports 108 can be oriented at any of various angles with respect to the flow path
through the flow cell 100. In the illustrated embodiment, four transducer ports 108 are provided,
each oriented at an oblique angle to the flow path through the flow cell 100. It will be
appreciated that any number of pairs of transducer ports can be incorporated. Flow cell 100 also
includes an electronic circuit mount 110 and an electronic circuit housing 112 in which the
circuitry for controlling the transducers to calculate flow is located. Electrical conductors (not
shown) connect the transducer to the circuitry of the electronics housing 112.
[0017]
In operation, the medium (eg, gas, liquid, or multiphase) flows through the lumen 104 and time
of flight or other algorithm based on transmission and reception of ultrasound by a transducer
mounted at the port 108 The flow rate is measured.
[0018]
Of course, the illustrated flow cell 100 is merely exemplary, and the transducer system disclosed
herein can be used with any of a variety of flow cells, and applications that do not include flow
cells. It can be used.
The transducer system disclosed herein may be a transit time flowmeter, a Doppler flowmeter, a
correlation flowmeter, a transmission reflection flowmeter, a wet or non-wet arrangement, a
portable or dedicated flow cell, and / or a single or multiple channel. It can be used with flow
cells. Applications in which the transducer system disclosed herein may be used include water,
wastewater, process fluids, chemicals, hydrocarbons, oils, gases, controlled transfer, multiphase
top or upstream, etc. Exemplary flow cells that can use the transducers disclosed herein include
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PANAFLOW, DIGITALFLOW, and SENTINEL flow meters available from General Electric
Company.
[0019]
FIGS. 3 and 4 illustrate an exemplary embodiment of a “floating” transducer system 200. In
existing transducer systems, the process pressure in the flow cell lumen moves the transducer
system away from the process fluid and attempts to contact the transducer mounting hardware
on which the flow cell or transducer system is mounted. The higher the process pressure, the
greater the acoustic coupling between the transducer system and the flow cell, and the greater
the short circuit noise.
[0020]
The floating transducer system 200 includes a floating portion that is prevented from contacting
the stationary portion of the system, or at least contacts the stationary portion with a force less
than that otherwise applied, and thus Reduce acoustic coupling to the flow cell. In particular,
floating transducer system 200 includes a path for process pressure to reach a pressure balance
surface “at the back” of the floating portion of the system. The geometry of the pressure
balancing surface is selected such that the force exerted by the process pressure on the "front" of
the floating portion is substantially equal to the force exerted by the process pressure on the
"back" of the floating portion. A separation gap is held between the floating portion of the
floating transducer system 200 and the stationary portion of the system, or at least the force that
causes the floating portion to contact the stationary portion is reduced. A similar arrangement is
provided to balance the forces exerted by the atmospheric pressure on the floating part.
[0021]
As the process pressure increases or decreases, the forces on the "front" and "rear" of the floating
portion also increase or decrease. As such, the noise coupling between the floating portion and
the fixed portion remains substantially the same regardless of the process pressure. As a result,
the noise amplitude is also substantially constant regardless of the process pressure.
[0022]
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7
As shown in FIGS. 3 and 4, the floating transducer system 200 includes a transducer assembly
202 having a transducer head 204, a transducer stem 206, and a transducer connector 208. The
floating transducer system 200 also includes a pressure mount assembly 210 having a seal plug
212, a piston 214, and an outer sleeve 216. Also, clamps 218 are included to help hold the
transducer assembly 202 within the pressure mounting assembly 210. Also, the floating
transducer system 200 may be provided in the grooves of each of the various parts of the system
to provide a seal between the said parts and the other parts of the system and to further reduce
the acoustic coupling. It includes one or more o-rings or gaskets 220, 222, 224, 226.
[0023]
The transducer head 204 houses an ultrasonic transducer, such as a piezoelectric crystal or
ceramic, configured to generate an ultrasonic mechanical wave in response to the applied power.
In the illustrated embodiment, the transducer head 204 is a hollow cylindrical container to which
an ultrasound transducer is attached. Although ultrasonic piezoelectric elements are generally
described herein, any of the transducer systems disclosed herein may be other types of
transducers (e.g., non-ultrasound transducers, magnetostrictive transducers, capacitive)
Transducers etc. can be used.
[0024]
Transducer stem 206 includes a first portion 228 to which transducer head 204 is connected
using any suitable connection mechanism, such as, for example, a weld connection, a press-fit
connection, or a threaded connection. Also, the transducer stem 206 defines a sealing surface on
which the first O-ring 220 forms a seal between the transducer stem and the seal plug 212, as
described in further detail below. Including 230. The transducer stem 206 also includes a second
stepped portion 232 defining an outwardly threaded surface for engaging a corresponding
inwardly threaded surface of the piston 214. The transducer stem 206 also includes a second
portion 234, which is long enough to extend completely through the outer sleeve 216. The
second portion 234 includes an internally threaded surface for engaging a corresponding
outwardly threaded surface of the transducer connector 208. Transducer stem 206 defines a
central lumen from which the electrical leads extend from the ultrasonic transducer of
transducer head 204 to transducer connector 208.
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[0025]
The transducer connector 208 substantially closes the second end of the transducer stem 206
(eg, via a threaded connection or other suitable connection mechanism as described above) to
place the transducer system in the flow cell electronics housing. The electrical connection is
configured to provide an electrical connection between the internal electronics (e.g., the
piezoelectric element and the associated conductor) of the floating transducer system 200 and
the external conductor.
[0026]
The piston 214 is coupled to the transducer stem 206 such that the longitudinal position of the
piston relative to the transducer stem is fixed.
In the illustrated embodiment, the piston 214 has a bore formed therein and is configured to
receive the second stepdown portion 232 of the transducer stem 206 in threaded engagement.
Including. Also, the first portion 236 includes a groove formed in its outer surface to receive at
least a portion of the second O-ring 222. The second o-ring 222 is configured to form a seal
between the first portion 236 of the piston 214 and the seal plug 212. The piston 214 also
includes a second portion 238 that defines a central lumen in which a second portion 234 of the
transducer stem 206 is received. The outer surface of the second portion 238 defines a sealing
surface on which the third O-ring 224 forms a seal between the piston 214 and the outer sleeve
216, as described in more detail below. The diameter of the second portion 238 of the piston
214 is smaller than the diameter of the first portion 236 so that a shoulder is formed at the
junction of the first and second portions, the shoulder being a process fluid Define a pressure
balance surface 240 facing away from the
[0027]
Seal plug 212 includes a first portion 242 having a bore formed therein and configured to
receive a first stepped portion 230 of transducer stem 206. Also, the first portion 242 includes a
groove formed in its inner surface to receive at least a portion of the first O-ring 220, such that
the first O-ring includes the transducer stem 206 and the seal plug Form a seal between it and
212. Seal plug 212 also includes a second portion 244 defining an inner bore in which a first
portion 236 of piston 214 is received. The second o-ring 222 provides a seal between the first
portion 236 of the piston 214 and the interior of the bore. The outer surface of the second
portion 244 defines a threaded surface configured to engage a corresponding inwardly threaded
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lumen formed in the first portion 246 of the outer sleeve 216.
[0028]
The outer sleeve 216 also includes a second portion 248 that defines a central lumen in which
the second portion 238 of the piston 214 is received. A groove is formed on the inner surface to
receive at least a portion of the third O-ring 224. The third o-ring 224 is configured to form a
seal between the second portion 238 of the piston 214 and the outer sleeve 216. Also, the outer
sleeve 216 includes a groove formed on its outer surface to receive at least a portion of the
fourth o-ring 226. The fourth o-ring 226 is configured to form a seal between the outer sleeve
216 and the flow cell (eg, one of the transducer ports of the flow cell) to which the floating
transducer system 200 is mounted. Also, the outer sleeve 216 includes an outwardly threaded
surface for engaging a corresponding threaded portion of the flow cell port.
[0029]
Clamp 218 includes first and second semi-cylindrical portions configured to fit around
transducer stem 206. Clamp 218 also includes one or more adjustment screws that can be
tightened or loosened to engage or disengage the clamp from transducer stem 206. Clamp 218
also includes a recess 250 in which a longitudinally extending tab portion 252 of piston 214 is
received to prevent the piston from rotating relative to transducer stem 206 when the clamp is
engaged.
[0030]
It will be appreciated that the floating transducer system 200 includes the floating portion (eg,
the transducer head 204, the transducer stem 206, and the piston 214) and the fixed portion (eg,
the seal plug 212 and the outer sleeve 216).
[0031]
As shown in FIG. 5, process pressure acts on several surfaces of the floating portion of floating
transducer system 200.
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(The surface on which the process pressure acts is shown using a first type of hatching, as noted
in the legend of FIG. 5). ) In particular, the process pressure acting on the surface 254 of the
transducer head 204 facing the direction of the process fluid usually tends to make the floating
part firmly in contact with the stationary part and also the surrounding flow cell, and noise
Provides acoustic coupling that propagates easily. However, because the threaded interface
between the seal plug 212 and the outer sleeve 216 is not well sealed, process pressure spreads
through the threaded interface and acts on the pressure balancing surface 240 facing away from
the process fluid. The pressure balancing surface 240 is defined by a shoulder or a stepped
portion where the first portion 236 of the piston 214 mates with the second portion 238 of the
piston. Process pressure is contained near the pressure balancing surface 240 by the second and
third o-rings 222, 224. The fourth o-ring 226 prevents process pressure from leaking around the
outer surface of the outer sleeve 216 and provides additional acoustic noise attenuation between
the sleeve and the flow cell.
[0032]
The geometry of the pressure balancing surface 240 is selected to balance the force exerted by
the process pressure on the process fluid with the force exerted by the process pressure away
from the process fluid, and as such, the floating transducer system Hold the gap 256 between the
floating portion of the 200 and the stationary portion of the system, or at least reduce the force
that causes the floating portion to contact the stationary portion. For example, the surface area of
pressure balancing surface 240 is substantially the total surface area of the entire surface facing
the process fluid of the floating portion subject to process pressure substantially the total surface
area of the entire surface facing away from the process fluid of the floating portion subjected to
process pressure. Or approximately equal to. By substantially or approximately equalizing, each
surface area is sufficiently equivalent to one another to be functionally equivalent to
manufacturing tolerances, thermal expansion, thermal contraction, etc., as will be readily
understood by those skilled in the art. Means close.
[0033]
Also, as shown in FIG. 5, atmospheric pressure acts on some surfaces of the floating portion of
floating transducer system 200. (Atmospheric pressure acting surfaces are shown using a second
type of hatching, as noted in the legend of FIG. 5). 2.) in particular the atmospheric pressure
acting on the shoulder 258 defined at the transition between the first and second stepped
portions of the transducer stem, between the second stepped portion and the second portion of
the transducer stem Shoulder 260 defined at the transition of the fluid, and the surface 262 of
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the piston 214 facing away from the process fluid, generally move the floating portion in the
There is a tendency to try. However, because the screw interface between the transducer stem
206 and the piston 214 is not well sealed, atmospheric pressure will spread through the screw
interface and act on the pressure balance surface 264 facing in the direction towards the process
fluid. The pressure balancing surface 264 is defined by the distal first end of the piston 214.
Atmospheric pressure is contained near the pressure balancing surface 264 by the first and
second O-rings 220, 222.
[0034]
The geometry of the pressure balancing surface 264 is selected to balance the force exerted by
the atmospheric pressure on the process fluid with the force exerted by the atmospheric pressure
away from the process fluid, and as such, the floating transducer system Retain the gap 266
between the floating and fixed portions of 200, or at least reduce the force that causes the
floating portion to contact the fixed portion. For example, the surface area of the pressure
balancing surface 264 is substantially the total surface area of the entire surface facing the
process fluid of the floating part under atmospheric pressure substantially the total surface area
of the entire surface facing the process fluid of the floating part under atmospheric pressure. Or
approximately equal to. By substantially or approximately equalizing, each surface area is
sufficiently equivalent to one another to be functionally equivalent to manufacturing tolerances,
thermal expansion, thermal contraction, etc., as will be readily understood by those skilled in the
art. Means close.
[0035]
In short, the floating transducer system 200 faces, and faces away from, the process fluid, each
configured to balance or at least partially offset the forces exerted by the process pressure and
the atmospheric pressure, respectively. Include pressure balancing surfaces 240, 264, thus
maintaining the gap 256, 266 between the floating portion and the fixed portion, or at least
reducing the force that causes the floating portion to contact the fixed portion Do. This is
effective to reduce the propagation of noise from the transducer to the surrounding flow cell and
ultimately to the receiving transducer.
[0036]
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6 and 7 show an exemplary embodiment of a "fixed" transducer system 300. As shown in FIG. In
existing transducer systems, an important part of the transducer system comes in direct metal-tometal contact with the transducer bore in the flow cell, which undesirably leads to strong
acoustic noise coupling. Fixed transducer system 300, on the one hand, includes one or more
acoustic attenuation elements configured to limit noise coupling between the transducer system
and the flow cell. The fixed transducer system 300 also includes one or more interruption
grooves or channels to limit the cross-sectional area that ultrasound propagates through the back
or side of the transducer. The stationary transducer system 300 also includes an annular
protrusion configured to act as a standoff between the transducer system and the flow cell. The
length of the protrusions is significantly less than the total length of the transducer system, so
that the contact area between the protrusions and the flow cell is significantly less than the total
surface area of the flow cell bore.
[0037]
As shown in FIGS. 6 and 7, stationary transducer system 300 includes a transducer assembly
having a transducer head 304, a transducer stem 306, and a transducer connector 308. The
stationary transducer system 300 also includes one or more acoustic attenuation elements 310,
312, an attenuation washer 314, and a retaining nut 316 to reduce acoustic noise coupling.
[0038]
The transducer head 304 houses an ultrasonic transducer, such as a piezoelectric crystal or
ceramic, configured to generate an ultrasonic mechanical wave in response to an applied voltage.
In the illustrated embodiment, the transducer head 304 is a hollow cylindrical container to which
an ultrasound transducer is attached. Although ultrasonic piezoelectric elements are generally
described herein, any of the transducer systems disclosed herein may be other types of
transducers (e.g., non-ultrasound transducers, magnetostrictive transducers, capacitive)
Transducers etc. can be used.
[0039]
Transducer stem 306 includes a first portion 318 to which transducer head 304 is connected
using any suitable connection mechanism, such as, for example, a weld connection, a press-fit
connection, or a threaded connection. Also, the first portion 318 includes first and second
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grooves or channels formed therein in which respective sound attenuating elements (e.g. O-rings)
310, 312 are disposed. During assembly, O-rings 310, 312 are disposed between the transducer
stem 306 and the surrounding flow cell bores to isolate the transducer stem from metal-to-metal
contact to reduce acoustic noise coupling. Although less than two o-rings may be used (e.g. one
o-ring), the use of more than one o-ring provides additional support to prevent the transducer
stem 306 from rocking in the flow cell bores Are conveniently provided to the transducer stem
306. Although the o-ring channel is shown and described as being in the first portion 318 of the
transducer stem 306, one or more of the o-ring channels may or may not be present, with or
without the additional o-ring channel formed in the first portion. It will be appreciated that a ring
channel may be formed in the second portion 320 of the transducer stem.
[0040]
Transducer stem 306 also includes an annular interrupt groove or channel 322. The annular
interrupt groove 322 reduces the cross-sectional area along the longitudinal portion of the
transducer stem 306 and reduces the area that acoustic noise propagates through the rigid
structure of the transducer stem. In such an arrangement, the noise coupling is less than that
without channels and the transducer stem 306 is simply a full solid wall, as acoustic noise is not
easily coupled through the air gap provided by the channels 322. . In addition, various metal
thicknesses result in variations in acoustic transfer characteristics (eg, speed of sound, acoustic
impedance, etc.) that tend to reject acoustic energy from propagating it.
[0041]
The annular interrupt groove 322 may be any of various depths of the wall of the transducer
stem 306 (eg, at least about 10%, at least about 25%, at least about 50%, at least about 75%, and
/ or at least about 90%). You can get into it. In some embodiments, the annular interrupt groove
322 is maintained to the greatest extent possible while retaining the structural integrity of the
transducer stem 306 given the intended application (eg, process pressure, flow cell lumen
diameter, etc.) Get in. Although a single annular interrupt groove 322 is shown and described
herein, it will be appreciated that more than one interrupt groove may be included.
[0042]
The transducer stem 306 also includes an annular protrusion or an increased circumferential
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14
area 324 configured to act as a standoff between the flow cell bore and the remainder of the
transducer stem 306. The annular protrusion 324 may be a continuous ring shaped protrusion
or may be a plurality of discrete standoffs spaced around the circumference of the transducer
stem 306. The length of the annular protrusion 324 may be significantly shorter than the total
length of the transducer stem 306 (e.g., less than about 50%, less than about 20%, less than
about 10%, and / or less than about 5%) It is selected. By relatively shortening the length of the
annular protrusion 324 relative to the length of the transducer stem 306, the protrusion is
omitted and the transducer compared to the variation where most of the outer surface of the
stem is in direct contact with the flow cell bores. The contact area between the stem and the flow
cell port is significantly reduced. By reducing the contact area, less acoustic noise coupling is
generated between the fixed transducer system 300 and the flow cell.
[0043]
Transducer stem 306 also includes an internally threaded bore configured to mate with a
corresponding screw formed on the outside of transducer connector 308. Transducer stem 306
defines a central lumen from which the electrical leads extend from the ultrasonic transducer of
transducer head 304 to transducer connector 308.
[0044]
Transducer connector 308 substantially closes the second end of transducer stem 306 (e.g., via a
threaded connection as described above) to electrically connect stationary transducer system
300 to the flow cell electronics housing. In order to provide electrical connection between the
internal electronics (e.g., piezoelectric elements and associated conductors) of the fixed
transducer system 300 and the external conductor.
[0045]
The stationary transducer system 300 also includes a retaining nut 316 disposed on the
transducer stem 306 without contacting the transducer stem.
Retaining nut 316 includes an outwardly threaded surface configured to engage a corresponding
threaded surface of the flow cell port to prevent movement of the stationary transducer system
300 away from the flow cell port from the process fluid Configured to Attenuation washer 314 is
disposed on the transducer stem 306 and is located between the annular projection 324 and the
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retaining nut 316. As discussed below, the damping washer 314 is formed of an acoustic
damping material to reduce the acoustic noise coupling between the transducer stem 306 and
the retaining nut 316 and ultimately between the flow cell and the receiving transducer.
[0046]
During operation, the process pressure of the flow cell flow path is otherwise undesirable,
causing the stationary transducer system 300 to move away from the process fluid and attempt
to firmly contact the retaining nut 316 and further to the surrounding flow cell. In particular,
acoustic noise is coupled to the flow cell. However, a dampening washer 314 is disposed between
the transducer stem 306 and the retaining nut 316 to provide acoustic isolation and reduce the
degree to which noise is coupled from the stem to the nut and flow cell.
[0047]
FIGS. 8 and 9 illustrate an exemplary embodiment of a “floating sleeve” transducer system
400. The floating sleeve transducer system 400 includes a piston sleeve disposed around the
transducer stem, and an o-ring configured to attenuate acoustic coupling between the stem and
the sleeve and between the sleeve and the flow cell . In addition, an acoustic damping washer or
other element is placed between the sleeve and the nut in the direction of the process pressure.
[0048]
As shown, the floating sleeve transducer system 400 includes a transducer assembly having a
transducer head 404, a transducer stem 406, and a transducer connector 408. The floating
sleeve transducer system 400 also includes a sleeve assembly having a piston 412, a damping
washer 414, and a retaining nut 416. Also, a clamp 418 and a retaining ring 420 are included to
help retain the transducer assembly within the sleeve assembly. The floating sleeve transducer
system 400 also includes one or more o-rings or gaskets 422, 424, 426, 428 to seal between
various parts of the system and to reduce acoustic noise coupling.
[0049]
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Transducer head 404 contains an ultrasound transducer, such as a piezoelectric crystal or
ceramic, configured to generate ultrasound mechanical waves in response to an applied voltage.
In the illustrated embodiment, the transducer head 404 is a hollow cylindrical container to which
an ultrasound transducer is attached. Although ultrasonic piezoelectric elements are generally
described herein, any of the transducer systems disclosed herein may be other types of
transducers (e.g., non-ultrasound transducers, magnetostrictive transducers, capacitive)
Transducers etc. can be used.
[0050]
Transducer stem 406 includes a first portion 430 to which transducer head 404 is connected
using any suitable connection mechanism, such as, for example, a weld connection, a press-fit
connection, or a threaded connection. Also, the transducer stem 406 defines a sealing surface in
which the first and second o-rings 422, 424 form a seal between the transducer stem and the
piston 412, as described in further detail below. It includes a lowered second portion 432. The
second portion 432 is long enough to extend completely through the sleeve assembly. The
second portion 432 includes an internally threaded surface for engaging a corresponding
outwardly threaded surface of the transducer connector 408. Transducer stem 406 defines a
central lumen from which the electrical leads extend from the ultrasonic transducer of
transducer head 404 to transducer connector 408.
[0051]
Transducer connector 408 substantially closes the second end of transducer stem 406 (e.g., via a
threaded connection as described above) to electrically connect the transducer system to the flow
cell electronics housing. , Configured to provide an electrical connection between the internal
electronics (e.g., the piezoelectric element and the associated conductor) of the floating sleeve
transducer system 400 and the external conductor.
[0052]
The piston 412 is a tubular member disposed above the transducer stem 406 such that the
second portion 432 of the transducer stem 406 extends through the central lumen of the piston.
First and second sound attenuating elements such as, for example, first and second O-rings 422,
424 are disposed in grooves or channels formed in the inner surface of the piston and / or the
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outer surface of the transducer stem 406 Form a seal between the transducer stem and reduce
acoustic noise coupling between the components. Also, the piston 412 includes a groove or
channel formed in its outer surface, which forms a seal between the piston and the flow cell, for
example to reduce acoustic noise coupling between the parts, for example Sound attenuating
elements such as the third and fourth o-rings 426, 428 are disposed. It should be appreciated
that although two sound attenuating elements 422, 424 are shown between the piston 412 and
the transducer stem 406, more or less than two attenuating elements may be included.
Furthermore, although two sound attenuating elements 426, 428 are shown between the piston
412 and the flow cell, it will be appreciated that more or less than two attenuating elements may
be included.
[0053]
The floating sleeve transducer system 400 also includes a retaining nut 416 disposed on the
transducer stem 406 without contacting the transducer stem 406. The retention nut 416
includes an outwardly threaded surface configured to engage a corresponding threaded surface
of the flow cell port to allow the floating sleeve transducer system 400 to move away from the
flow cell port from the process fluid Configured to prevent. Attenuation washer 414 is disposed
on transducer stem 406 and is located between piston 412 and retaining nut 416. As discussed
below, the damping washer 414 is formed of an acoustic damping material to reduce acoustic
noise coupling between the piston 412 and the retaining nut 416 and ultimately between the
flow cell and the receiving transducer.
[0054]
During operation, the process pressure of the flow cell's flow path otherwise moves the floating
sleeve transducer system 400 away from the process fluid and attempts to firmly contact the
retaining nut 416 and further to the surrounding flow cell, which is desirable. Not to combine
acoustic noise into the flow cell. However, a damping washer 414 is disposed between the piston
412 and the retaining nut 416 to provide acoustic isolation and reduce the degree to which noise
is coupled from the piston to the nut and flow cell.
[0055]
The clamp 418 includes first and second semi-cylindrical portions configured to fit around the
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transducer stem 406 to prevent the piston 412 from moving away from the process fluid relative
to the stem Configured The clamp 418 also includes one or more adjustment screws that can be
tightened or loosened to engage or disengage the clamp from the transducer stem 406. Retaining
ring 420 is a spring clip adapted to fit around the transducer stem 406 and engage a groove
formed on the outside of the transducer stem. In this manner, the retaining ring 420 prevents the
piston 412 from moving relative to the transducer stem 406 in the direction of the process fluid.
[0056]
In operation, the first and second o-rings 422, 424 reduce the amount of acoustic noise coupled
from the transducer stem 406 to the piston 412. The transmission of any noise coupled to the
piston 412 is prevented from coupling to the flow cell by the third and fourth o-rings 426, 428.
Furthermore, as the process pressure tends to move the floating sleeve transducer system 400 in
a direction away from the process fluid, the damping washer 414 causes acoustic noise to
propagate from the piston 412 to the retaining nut 416 and finally to the surrounding flow cell
Attenuate
[0057]
The components of the transducer system disclosed herein may be formed from any of a variety
of materials including, but not limited to, metals such as, for example, stainless steel, titanium,
aluminum, iron and / or combinations thereof. it can. The acoustic damping elements and
damping washers disclosed herein include, but are not limited to, graphite, elastic material (eg,
neoprene), fluoroelastic material, polytetrafluoroethylene (PTFE) and / or combinations thereof.
It can be made of a damping material.
[0058]
The features disclosed herein with respect to any particular embodiment may be combined with
or incorporated into any other embodiment.
[0059]
The transducer system disclosed herein provides several advantages and / or technical effects.
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For example, some embodiments reduce acoustic noise coupling between the transducer and the
flow cell, improve the SNR of the flow meter, and provide more accurate flow measurement.
[0060]
Although the transducer systems disclosed herein are generally described in the context of flow
meters, it will be appreciated that they have application in a variety of other contexts. For
example, the transducer system disclosed herein can be used in any system where it is desirable
to reduce the acoustic noise coupling between the transducer and the part on which the
transducer is mounted. Such systems include ultrasound imaging systems, ultrasound defect
detection systems, ultrasound cleaners, ultrasound mixers, ultrasound sensors, ultrasound
welding systems, and the like.
[0061]
This written description uses examples to disclose the invention and includes the best mode.
Also, using examples to enable any person skilled in the art to practice the present invention,
including making and using any device or system, and performing any incorporated method. The
patentable scope of the invention is defined by the claims, and may include other examples that
occur to those skilled in the art. If such other embodiments have structural elements that do not
differ from the literal words of the claims, or if they contain structural elements that are
equivalent with no substantial difference to the literal words of the claims, Such other
embodiments are intended to be within the scope of the claims.
[0062]
Reference Signs List 100 flow cell 102 pipe 104 lumen 106 flange 108 port 110 electronics
mount 112 electronics housing 200 floating transducer system 202 transducer assembly 204
transducer head 206 transducer stem 208 transducer connector 210 pressure mounting
assembly 212 seal plug 214 piston 216 outer sleeve 218 clamp 220 1 O-ring, gasket 222
second O-ring, gasket 224 third O-ring, gasket 226 fourth O-ring, gasket 228 first portion 230
(of transducer stem 206) first step portion 232 first Second step portion 234 second portion 236
(of transducer stem 206) first portion 236 Stone 214) 238 second part (of piston 214) 240
pressure balancing surface 242 first part (of seal plug 212) 244 second part (of seal plug 212)
246 first part (of outer sleeve 216) ) 248 second portion (of outer sleeve 216) 250 recess 252
longitudinally extending tab portion 254 surface (of transducer head 204) 256 gap 258 shoulder
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260 shoulder 262 surface (of piston 214) 264 pressure balancing surface 266 gap 300 Fixed
Transducer System 304 Transducer Head 306 Transducer Stem 308 Transducer Connector 310
O-Ring, Acoustic Attenuation Element 312 O-Ring, Acoustic Attenuation Element 314 Attenuation
Washer 316 Retention Nut 318 First Part (Transducer Stem 3 06) 320 second part (of
transducer stem 306) 322 channel, annular interrupt groove 324 annular projection, area of
increased circumferential area 400 floating sleeve transducer system 404 transducer head 406
transducer stem 408 transducer connector 412 piston 414 damping washer 416 Retaining nut
418 Clamp 420 Retaining ring 422 First O-ring, acoustic damping element, gasket 424 Second
O-ring, acoustic damping element, gasket 426 Third O-ring, acoustic damping element, gasket
428 Fourth O-ring, Sound attenuating element, gasket 430 first part (of transducer stem 406)
432 second part (of transducer stem 406)
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