JP7762014B2 - ultrasonic flow meter - Google Patents

Description

The present invention relates to an ultrasonic flow meter that operates based on the flow rate of a fluid, particularly a liquid, flowing through a pipe.

In situations where the exact flow rate of the fluid flowing through the pipe is not required, and it is sufficient to detect whether the fluid is flowing through the pipe at a flow rate above a certain value, in other words, in situations where the exact flow rate of the fluid flowing through the pipe is not required, ultrasonic flow switches that output an ON/OFF signal are used (Patent Document 1). Patent Document 1 also discloses a clamp-on ultrasonic flowmeter. A clamp-on ultrasonic flowmeter is a unit that incorporates the elements included in the clamp-on ultrasonic flowmeter and is installed at an appropriate location on the outer surface of the pipe as a retrofit.

A typical example of the clamp-on ultrasonic flow switch or flow meter disclosed in Patent Document 1 has a configuration in which a set of first and second ultrasonic elements are held by a single element holder. A flow meter with this configuration is called an "integrated clamp-on ultrasonic flow meter." The integrated clamp-on ultrasonic flow meter disclosed in Patent Document 1 has the first and second ultrasonic elements waterproofly and integrally held within a single element holder, with the elements positioned relative to one another by the single element holder. The integrated clamp-on ultrasonic flow meter eliminates the need for the user to perform the tedious task of positioning the first and second ultrasonic elements relative to one another while installing the flow meter on a pipe, making installation of the ultrasonic flow meter easy for the user. Patent Document 2 also discloses in detail the functional circuit blocks included in the clamp-on ultrasonic flow meter.

Patent Document 3 discloses two types of ultrasonic flowmeters. One is a "pulse Doppler" type, which uses a pulse Doppler method to measure flow rate. The other is a "flight time difference" type, which uses a transit time difference method to measure flow rate.

Japanese Patent Application Laid-Open No. 2016-217734 Japanese Patent Application Publication No. 2019-15549 WO2006/080182 A1

In a clamp-on ultrasonic flowmeter, the first ultrasonic element and the second ultrasonic element are acoustically coupled to the first and second element coupling surfaces, respectively, of the element holder on which the first and second ultrasonic elements are installed. The element holder generally includes a wedge material and is attached to the outer surface of the piping using a mounting fixture. This allows the pipe coupling surface of the element holder to be acoustically coupled to the piping.

The ultrasonic waves transmitted by the first ultrasonic element are guided into the fluid in the pipe through the first element coupling surface and the pipe coupling surface. The ultrasonic waves propagating through the fluid in the pipe are received by the second ultrasonic element through the pipe coupling surface and the second element coupling surface. The flow rate of the fluid in the pipe is calculated based on the output signal of at least one of the first and second ultrasonic elements. An on/off signal is generated and output based on the calculated flow rate and a predetermined threshold value.

The clamp-on ultrasonic flowmeter includes an intermediate ultrasonic shielding member positioned between the first ultrasonic element and the second ultrasonic element. The presence of the intermediate ultrasonic shielding member prevents ultrasonic waves emitted by the first or second ultrasonic element from propagating to the fluid in the pipe, and prevents them from traveling from the first ultrasonic element to the second ultrasonic element, or from traveling from the second ultrasonic element to the first ultrasonic element. This allows for more accurate determination of the flow rate of the fluid in the pipe. This advantage applies when measuring flow rate using the "transit time difference" method, but it may be a disadvantage when calculating flow rate using the "pulse Doppler" method.

When measuring flow rate using the "pulse Doppler" method, ultrasonic waves reflected by particles in the fluid are mixed with ultrasonic waves reflected by the boundary of internal components, such as the intermediate ultrasonic shielding member, which can reduce detection accuracy. Specifically, some of the ultrasonic waves emitted by the first ultrasonic element are reflected by bubbles in the liquid being measured. Another portion of the ultrasonic waves emitted by the first ultrasonic element are reflected by the intermediate ultrasonic shielding member, and these reflected ultrasonic waves become disturbance elements. If the ultrasonic waves of these disturbance elements are received by the first ultrasonic element, this can cause a reduction in detection accuracy. The same is true for wedge materials.

The object of the present invention is to provide an ultrasonic flowmeter that can prevent ultrasonic waves reflected by internal components from becoming a disturbance and reducing detection accuracy when measuring flow using the Doppler method.

A further object of the present invention is to provide an ultrasonic flowmeter that can improve detection accuracy in the "pulse Doppler" measurement mode under conditions where the liquid flowing through the pipe is typically at a high temperature, in a clamp-on ultrasonic flowmeter that has an element holder and first and second ultrasonic elements that are waterproofly held in the element holder either together or individually and that can be retrofitted to a pipe, typically an ultrasonic flowmeter in which the first and second ultrasonic elements are held together in a single element holder while being positioned relative to one another.

According to the present invention, the above technical problem is solved as follows:
An ultrasonic flow meter for measuring the flow rate of a fluid flowing through a pipe,
a first ultrasonic element that transmits and receives ultrasonic waves;
a second ultrasonic element that transmits and receives ultrasonic waves;
a first method for calculating a flow rate of the fluid in the pipe based on an output signal of the first ultrasonic element;
a second method for calculating the flow rate based on output signals of the first and second ultrasonic elements; and
an element holding portion that holds the first and second ultrasonic elements;
a mounting fixture that holds the element holding part and is detachably attached to the outer surface of the pipe,
The element holding unit is
a first element holding portion that supports the first ultrasonic element so as to be acoustically coupled to the first ultrasonic element;
a second element holding portion that supports the second ultrasonic element so as to be acoustically coupled to the second ultrasonic element;
Including,
the first element holding portion forms a first waveguide through which ultrasonic waves transmitted by the first ultrasonic element are guided into the fluid in the piping through the first element holding portion;
the second element holding portion forms a second waveguide through which ultrasonic waves propagated through the fluid in the piping pass through the second element holding portion and are received by the second ultrasonic element;
This is achieved by providing an ultrasonic flowmeter in which the first element holding portion is positioned so that ultrasonic waves transmitted from the first ultrasonic element are reflected by a surface of the first element holding portion facing the second element holding portion, and the reflected waves are not input to the first ultrasonic element.

In a preferred embodiment of the present invention, an intermediate ultrasonic shielding member is provided between the first and second element holding portions, and the ultrasonic waves emitted by the first ultrasonic element are reflected by the intermediate ultrasonic shielding member, and the reflected ultrasonic waves are prevented from returning to the first ultrasonic element. The effects and other objects of the present invention will become apparent from the detailed description of the embodiments below.

1 is a diagram illustrating the overall configuration of an ultrasonic flow rate detection device according to an embodiment applied to coolant management; The ultrasonic flow rate detection device of the embodiment shown in Figure 1 is configured to include a mounting base member, a measurement head member, and a flow meter display, and is a diagram for explaining that a temperature sensor and a concentration sensor are connected to the flow meter display. This is a diagram related to Figure 2 and is used to explain that the measurement head member is installed in a state where it is pressed against the metal pipe via the mounting base member, and the flow meter display is installed detachably to this measurement head member. 2 and 3, is a perspective view of an ultrasonic flow meter including a flow meter indicator. 1 is a perspective view of a flow meter indicator installed on a pipe and surrounded by a metal cover member, viewed obliquely from below. FIG. FIG. 6 is a diagram related to FIG. 5 and is a perspective view of a flowmeter indicator installed on a pipe and surrounded by a metal cover member, as viewed obliquely from above. 3 is a diagram for explaining the functions of the first and second ultrasonic elements applied to a switchable Doppler measurement operation mode and a switchable time difference measurement operation mode in the clamp-on ultrasonic flowmeter shown in FIG. 2. FIG. FIG. 1 is a diagram for explaining the principle of flow rate measurement using the "pulse Doppler" method, in which depths are divided and the flow velocity at each depth is determined. FIG. 1 is a longitudinal sectional view of a standard type ultrasonic flowmeter, which is one type of clamp-on ultrasonic flowmeter according to an embodiment. (I) shows the standard type ultrasonic flowmeter shown in Figure 9, (II) is a side view of the first and second wedge members extracted from the standard type, and (III) is a plan view of the first and second wedge members. FIG. 1 is a longitudinal sectional view of a high-temperature type ultrasonic flowmeter, which is another type of clamp-on ultrasonic flowmeter according to an embodiment of the present invention. (I) shows the high-temperature type ultrasonic flowmeter shown in Figure 11, (II) is a side view of the first and second wedge members extracted from the high-temperature type, and (III) is a plan view of the first and second wedge members. FIG. 12 is a cross-sectional view of FIG. 11 taken along a direction crossing the pipe, illustrating a state in which the measuring head is pressed against the mounting base member. This is an example of one display of the display that constitutes part of the clamp-on ultrasonic flow meter in the ultrasonic flow detection device of the embodiment, and shows that the flow sensor, temperature sensor, and concentration sensor that constitute the ultrasonic flow detection device are connected. 10 is a second display example of a display that constitutes part of a clamp-on ultrasonic flowmeter in the ultrasonic flow detection device of the embodiment, and is a display example that can be used to set the flow direction of a pipe, etc. The ultrasonic flow rate detection device of the embodiment has a function to calculate heat quantity using detected temperature and flow rate data, and this is an example of a display that can be displayed on the display to select whether to enable or disable this function. 10 is a diagram showing an example of a display that can be displayed on a display for selecting a unit for displaying flow rate and concentration in the ultrasonic flow rate detection device of the embodiment. 10 is a diagram showing an example of a display that can be displayed on a display to set what to assign to a plurality of channels of a flowmeter display in the ultrasonic flow rate detection device of the embodiment. 10 is a menu display screen that can be displayed on the flowmeter display in the ultrasonic flow rate detection device of the embodiment. An example of the display when the current value (flow rate) is selected on the menu display screen of FIG. 19 is shown. An example of a display when the current value (temperature) is selected on the menu display screen of FIG. 19 is shown. An example of the display when the current value (density) is selected on the menu display screen of FIG. 19 is shown. An example of the display when current values (list) is selected on the menu display screen of FIG. 19 is shown. This is a menu display screen of a display device that includes menu items such as "Settings" and "History." FIG. 24 shows an example of a time series "curve graph display" that can be displayed when the menu item "history" is selected. FIG. 24 shows an example of a time-series "bar graph display" that can be displayed when the menu item "history" is selected. 10 shows a screen relating to settings that can be displayed on the display in the ultrasonic flow rate detection device of the embodiment. 10 shows a screen on which the settings relating to the concentration sensor can be made using the display screen of the display device in the ultrasonic flow rate detection device of the embodiment. 10 shows a screen on which settings relating to flow rate can be made using the display screen of the display device in the ultrasonic flow rate detection device of the embodiment. 10 shows a screen on which settings relating to flow rate can be made using the display screen of the display device in the ultrasonic flow rate detection device of the embodiment.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings.

The ultrasonic flowmeter of the embodiment is operated by incorporating a concentration sensor and a temperature sensor. The ultrasonic flowmeter is an integrated clamp-on ultrasonic flowmeter with a display function. The ultrasonic flow detection device of the embodiment, which includes the integrated clamp-on ultrasonic flowmeter, concentration sensor, and temperature sensor, is optimized for managing coolant in machine tools.

Machine tools use water-soluble cutting fluids diluted with water. The diluted solution is called "coolant." Coolant contains only a small amount of active ingredients, and maintaining the coolant concentration at the appropriate level is essential to ensure that these trace ingredients exert their lubricating effect, prevent coolant decay, prevent rust, and prevent a decline in cutting performance. If the concentration is lower than the recommended value, the machining performance of machine tools will decline. Machine tool operators learn proper coolant management as a skill for improving production quality, reducing running costs, and improving work efficiency. For operators, proper coolant management, especially concentration management, is important for improving machine tool production quality, reducing running costs, and improving work efficiency.

Referring to Figure 1, reference numeral 2 denotes a coolant storage tank. Coolant storage tank 2 contains a water-soluble cutting fluid diluted with water, i.e., coolant. The coolant in coolant storage tank 2 is supplied to a machine tool (not shown) through metal piping 4.

A clamp-on ultrasonic flowmeter 6 is removably attached to the metal pipe 4 as a retrofit. A concentration sensor 8 with a detection section inserted into the coolant storage tank 2 is connected to the clamp-on ultrasonic flowmeter 6, as well as a temperature sensor 10 installed, for example, at a connecting portion of the pipe 4. The clamp-on ultrasonic flowmeter 6 also has a flowmeter display 64, which will be described later, and these elements together make up the ultrasonic flow detection device 12.

Figure 2 is a diagram illustrating a specific example of a clamp-on ultrasonic flowmeter 6. The clamp-on ultrasonic flowmeter 6 is composed of three components: a mounting base member 60, a measuring head member 62, and a flowmeter display 64. The mounting base member 60 can be removably installed at an appropriate location on the piping 4. The measuring head member 62 is equipped with first and second ultrasonic elements 66, 68 (Figure 7) that constitute the flow detection unit. This measuring head member 62 is removably assembled to the mounting base member 60, and the mounting base member 60 keeps the measuring head member 62 pressed against the piping 4.

A flowmeter display 64 is attached to the measurement head member 62 (see Figures 2 and 3). In Figure 2, (I) is a front view of the flowmeter display 64, and (II) is a rear view of the display 64. A concentration sensor 8 and a temperature sensor 10 are connected to the flowmeter display 64. The values detected by the concentration sensor 8 and the temperature sensor 10 are displayed on the display section 64a of the flowmeter display 64 as actual detected numerical values, without any processing such as calculations.

A first indicator light 64b is provided adjacent to the display unit 64a on the front of the flowmeter display 64 (Figures 2(I) and 4). This first indicator light 64b is preferably positioned so that it can be easily seen from above, below, left and right. In addition to the first indicator light 64b on the flowmeter display 64, the ultrasonic flow detector 12 also has a second indicator light 62b on the measuring head member 62. This second indicator light 62b is preferably positioned so that it can be easily seen from above, left and right.

According to the ultrasonic flow detection device 12 of the embodiment, the first indicator light 64b and the second indicator light 62b turn on, turn off, or flash whether the flowmeter display 64 is installed on the piping 4 while separated from the measuring head member 62, or whether the flowmeter display 64 is installed on the piping 4 while incorporated into the measuring head member 62. As a result, the flowmeter display 64 has an operation unit 64c, which can be used to perform various settings on the display unit 64a. This setting work can be performed whether the flowmeter display 64 is separated from the measuring head member 62 or when the flowmeter display 64 is incorporated into the measuring head member 62. In either state, the setting work can be performed while visually checking the changes in the state of the first and second indicator lights 64b and 62b.

Referring to Figures 5 and 6, the ultrasonic flow detector 12 can preferably be fitted with a metal cover 80. By additionally installing the metal cover 80, the ultrasonic flow detector 12 can be protected from sunlight, even when installed outdoors, for example. This prevents deterioration of the resin housing of the ultrasonic flow detector 12 due to the UV components of sunlight. For example, the infrared components of sunlight can cause the temperature of the flow meter display 64 to rise, potentially damaging the display 64. Furthermore, continuous water hitting the ultrasonic flow detector 12 directly due to external rain, for example, can cause moisture to enter the interior of the ultrasonic flow detector 12. These risks can be prevented by the metal cover 80.

The metal cover 80 has an opening 80a (Figure 5) in the area corresponding to the connection port, and a waterproof cable can be passed through this opening 80a. The metal cover 80 also has a hinge 82 (Figure 6), and by opening the metal cover 80 using the hinge 82, it is possible to perform setting operations for the flowmeter display 64, i.e., operate the keys on the operating section 64c, without removing the metal cover 80.

The clamp-on ultrasonic flowmeter 6 is most preferably configured as an integrated clamp-on ultrasonic flowmeter (Figure 7). In the measurement head member 62, the first ultrasonic element 66 and the second ultrasonic element 68 are preferably integrally held in a single element holder 70.

Referring to FIG. 7 , the measurement head member 62 incorporates first and second ultrasonic elements 66, 68 that transmit and receive ultrasonic waves, and the relative positions of the first and second ultrasonic elements 66, 68 are fixed by an element holder 70. The first and second ultrasonic elements 66, 68 are typically piezoelectric elements. The first and second ultrasonic elements 66, 68 are positioned by the element holder 70 so as to be spaced apart in the axial direction of the pipe 4 on the generatrix of the pipe 4. The integrated clamp-on ultrasonic flowmeter 6 of the embodiment is a so-called V-configuration type or reflection-configuration type, specified from the perspective of the second measurement mode that measures based on the principle of the "transit time difference" method described below.

The clamp-on ultrasonic flowmeter 6 according to this embodiment can measure flow rate using both the "transit time difference" method and the "pulse Doppler" method. The "pulse Doppler" method detects the flow rate of a fluid from the speed at which air bubbles and other foreign matter contained in the fluid flowing through the pipe move, assuming that they move at the same speed as the fluid. This "pulse Doppler" method uses only one of the elements, for example the first ultrasonic element 66, to transmit ultrasonic pulses to the fluid being measured in the pipe at regular intervals. This method uses the principle of Doppler shift, in which the frequency of ultrasonic echo waves reflected by foreign matter such as air bubbles mixed in the fluid changes by an amount proportional to the flow rate.

On the other hand, the "flight time difference" method uses a pair of integrated transmit/receive ultrasonic elements to compare the first ultrasonic propagation time from upstream to downstream with the second ultrasonic propagation time from downstream to upstream, and uses the time difference between these first and second ultrasonic propagation times to determine the average flow velocity and flow rate of the fluid being measured.

Compared to the "pulse Doppler" method, the "transit time difference" method is more accurate and has a faster response time, but is less resistant to bubbles. The "pulse Doppler" method can only measure when a certain amount of reflectors, or bubbles, are uniformly present in the fluid being measured, and is unable to provide high-precision measurements in fluids where there are insufficient bubbles or where bubbles are unevenly distributed. The presence of impurities such as bubbles in the fluid being measured makes it difficult for the "transit time difference" method to achieve high-precision measurements. For this reason, the "transit time difference" method is suitable for detecting the flow rate of liquids with few impurities or pure water.

A clamp-on ultrasonic flowmeter with two measurement modes - a first measurement mode that uses a single ultrasonic element to measure based on the principle of the "pulse Doppler" method, and a second measurement mode that uses a pair of ultrasonic elements to measure based on the principle of the "time difference of flight" method - is called a "hybrid switch," and the clamp-on ultrasonic flowmeter 6 of this embodiment is a hybrid switch.

The clamp-on ultrasonic flowmeter 6 includes a first wedge member 162 serving as the first ultrasonic transmission unit 16 adjacent to the first ultrasonic element 66 included in the measuring head member 62, and a second wedge member 182 serving as the second ultrasonic transmission unit 18 adjacent to the second ultrasonic element 68. The first wedge member 162 is incorporated into the element holding member 70 and has a first element bonding surface 162a that supports the first ultrasonic element 66 so as to be acoustically coupled with the first ultrasonic element 66, with the first ultrasonic element 66 mounted on this first element bonding surface 162a. The second wedge member 182 is incorporated into the element holding member 70 and has a second element bonding surface 182a that supports the second ultrasonic element 68 so as to be acoustically coupled with the second ultrasonic element 68, with the second ultrasonic element 68 mounted on this second element bonding surface 182a.

The measurement head member 62 also preferably includes first and second couplants 164, 184 adjacent to the first and second wedge members 162, 182, respectively. The first and second couplants 164, 184 form part of the first and second ultrasonic transmission units 16, 18, and also form a pipe coupling surface in the element holding unit 70 that acoustically couples with the pipe 4.

The measuring head member 62 has a circuit board 186 that controls the transmission and reception of the first and second ultrasonic elements 66, 68 and calculates the detected data. As mentioned above, the flow meter display 64 is detachably installed on the measuring head member 62. The flow meter display 64 receives the flow rate determined by the measuring head member 62 and displays it on the display unit 64a.

The measurement head member 62 includes a time difference measurement operation mode in which the first and second ultrasonic elements 66, 68 work together to perform flow rate measurements using the "flight time difference" method, and a Doppler measurement operation mode in which the first ultrasonic element 66 operates independently to perform flow rate measurements using the "pulse Doppler" method. These modes can be selected by the user or automatically selected based on, for example, the amount of bubbles in the coolant. For example, several cycles of flow rate measurement using the flight time difference method are performed, followed by repeated flow rate measurement using the pulse Doppler method. When there are few bubbles, the flow rate based on the flight time difference is output, and when the number of bubbles increases, flow rate measurement is performed using the Doppler method. When there are many bubbles, the Doppler measurement operation mode is automatically selected, and when there are few bubbles, the time difference measurement operation mode is automatically selected.

In Figure 7, the solid line RL arrow indicates that the first and second ultrasonic elements 66, 68 work together to measure flow rate based on the principle of "time of flight" method. On the other hand, the dashed line DL arrow indicates that the first ultrasonic element 66 operates independently to measure flow rate based on the principle of "pulse Doppler" method.

Figure 8 is a diagram explaining the principle of flow rate measurement using the "pulse Doppler" method. Figure 8 is a diagram explaining how the depth inside the pipe 4, i.e., the depth from the first ultrasonic element 66 and the first ultrasonic transmission unit 16, is divided and the flow velocity is calculated for each depth. By calculating the flow velocity for each depth, the flow velocity distribution for each depth is measured. The number of depth divisions, i.e., the number of depth points, is determined by the processing power of the measurement head member 62. The flow rate can then be calculated by converting the flow velocity distribution, for example, by averaging it. Of course, the flow rate can also be calculated by integration. Specifically, the flow velocity distribution inside the pipe can be obtained in detail, and the flow rate can be calculated by multiplying the flow velocity for each depth by the width and essentially integrating it. Alternatively, the flow velocities obtained at multiple depth points can be averaged and then multiplied by a predetermined coefficient to calculate the flow rate.

The measurement head member 62 includes a plate-shaped intermediate ultrasonic shielding member 20 positioned between the first wedge member 162 and the second wedge member 182 and standing upright. This intermediate ultrasonic shielding member 20 prevents ultrasonic waves emitted by the first ultrasonic element 66 from traveling to the second ultrasonic element 68 without passing through the fluid when operating in the time difference measurement operation mode. In relation to the intermediate ultrasonic shielding member 20, of the multiple faces constituting the first wedge member 162, the face 162e facing the intermediate ultrasonic shielding member 20 is oriented at an angle. This prevents reflected waves reflected by the face 162e of the first wedge member 162 from returning to the first ultrasonic element 66 when operating in the Doppler measurement operation mode. This reflected wave return prevention function can be achieved by inclining the face 162e of the first wedge member 162 with respect to the standing faces constituting the intermediate ultrasonic shielding member 20 (Figure 7). Here, "inclined" means that the surface 162e of the first wedge member 162 and the surface that constitutes the intermediate ultrasound shielding member 20 are not parallel.

Referring to Figures 10 and 12 (III), which show typical examples, it is preferable to configure all of the multiple surfaces that make up the outline of the first wedge member 162 so that each surface is inclined relative to the surface that makes up the intermediate ultrasound shielding member 20, for example. In other words, it is preferable to configure all of the multiple surfaces that make up the outline of the first wedge member 162 so that ultrasonic waves reflected from each surface are prevented from returning to the first ultrasonic element 66 (like the inclined surface 162e of the first wedge member 162). However, since inclining the surfaces increases the area occupied by the wedge member, it is desirable to only incline the surface 162e on the side of the second wedge member 182.

When considering only the first ultrasonic element 66, which is also used for Doppler measurement, positioning the first ultrasonic element 66 at an angle relative to the generatrix of the piping 4 is not necessarily desirable because it increases the volume occupied by the first ultrasonic transmission unit 16 associated with the first ultrasonic element 66. However, the integrated clamp-on ultrasonic flowmeter 6 included in the embodiment has a hybrid structure combining the "time-of-flight" method and the "pulse Doppler" method. In this hybrid structure, when operating in the "time-of-flight" method, tilting the first element coupling surface 162a of the first ultrasonic element 66 relative to the generatrix of the piping 4 means tilting it relative to the intermediate ultrasonic shielding member 20 standing between the first and second ultrasonic transmission units 16, 18. This tilt prevents reflected waves from returning, reducing the likelihood that waves reflected at the interface between the first wedge member 162 and the other member will return to the first ultrasonic element 66. As mentioned above, the reflected wave from the interface of the first wedge material 162 becomes a disturbance element in flow velocity measurements based on the principle of the "pulse Doppler" method. By eliminating this disturbance element, the accuracy of flow velocity measurements based on the principle of the "pulse Doppler" method can be improved.

The first wedge member 162, which constitutes part of the first ultrasonic transmission unit 16, and the second wedge member 182, which constitutes part of the second ultrasonic transmission unit 18, are made of a common material. Furthermore, the first couplant 164, which constitutes part of the first ultrasonic transmission unit 16, and the second couplant 184, which constitutes part of the second ultrasonic transmission unit 18, are made of a common material.

The couplant material is preferably an elastic couplant material such as polymer rubber (silicone rubber, epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, fluororubber, etc.) or gel-like substance (silicone gel, urethane gel, etc.). This couplant effectively exerts acoustic coupling effect under moderate compressive force. This compressive force is provided by a biasing member (typically spring force).

The first and second couplants 164, 184 are preferably made of perfluoroelastomer (FFKM). FFKM is known to be an elastomer with excellent chemical and heat resistance because the main chain of its molecular structure is entirely fluorine-bonded. The pipe 4 in which the measuring head member 62 is installed is heated by the high-temperature fluid flowing through it. In this harsh environment, the heat resistance of the ultrasonic flowmeter can be maintained by using first and second couplants 164, 184 made of FFKM.

Two types of measuring head members 62 are preferably prepared. Figures 9 and 10 show the first type, the standard type. Figures 11 and 12 show the second type, the high-temperature type. To distinguish between the standard type and the high-temperature type, the standard type measuring head is designated "62A," which is the reference number 62 with an "A" added. The high-temperature type measuring head is designated "62B," which is the reference number 62 with a "B" added.

The essential difference between the standard type measuring head 62A (Figures 9 and 10) and the high-temperature type measuring head 62B (Figures 11 and 12) is the height dimension of the first and second wedge members 162, 182. If the height dimension of the first and second wedge members 162, 182 included in the standard type is indicated by "H1" and the height dimension of the first and second wedge members 162, 182 included in the high-temperature type is indicated by "H2," the high-temperature type has a larger height dimension than the standard type (H2 > H1). As a result, with the high-temperature type measuring head 62B, the board 186 and flowmeter display 64 can be placed further away from the piping 4 than with the standard type. This prevents thermal degradation of the thermally sensitive board 186 and flowmeter display 64.

The first and second ultrasonic elements 66, 68 are optional, but are preferably constructed from composite piezoelectric materials. Reverberation when the first and second ultrasonic elements 66, 68 transmit their own ultrasonic waves can contribute to reduced detection accuracy when receiving them. To address this issue, using a composite piezoelectric material can shorten the reverberation time, thereby improving detection accuracy.

Figures 9 and 10 both show the standard type measuring head 62A, but Figure 10 shows the first and second wedge members 162, 182 included in the measuring head 62A. Figures 11 and 12 both show the high-temperature type measuring head 62B, but Figure 12 shows the first and second wedge members 162, 182 included in the measuring head 62B.

In Figures 10 and 12, the actual waveguides 162b, 182b of the first and second wedge members 162, 182 are shown in phantom lines. The second wedge member 182 is not used during operation in the "pulse Doppler" mode. The outer contour of this second wedge member 182 is substantially the same as that of the waveguide 182b. In contrast, the first wedge member 162 is also used in the Doppler measurement operation mode, which performs flow measurement using the "pulse Doppler" mode. Please note that the actual waveguide 162b of the first wedge member 162 shown in Figures 10 and 12 is significantly different from the outer contour of the actual first wedge member 162, as can be seen by comparing it with the outer contour of the second wedge member 182. The outer contour of the first wedge member 162 is larger than the substantial waveguide 162b, and has a shape in which excess pad 162c is added to the substantial waveguide 162b. Referring to Figures 10 and 12, the first wedge member 162 has a first marginal portion 162c-1 adjacent to the intermediate ultrasound shielding member 20 having a generally triangular shape in side view. The first excess pad portion 162c-1 has a generally triangular shape with the apex on the side of the first couplant 164 attached to the first wedge member 162 and the base on the side of the first element coupling surface 162a, and this first excess pad portion 162c-1 is thicker on the side of the first element coupling surface 162a. By making the first excess pad portion 162c-1 adjacent to the intermediate ultrasonic shielding member 20 have a shape different from the actual waveguide 162b, ultrasonic waves reflected by the intermediate ultrasonic shielding member 20 can be prevented from returning to the first ultrasonic element 66.

The second excess pad portion 162c-2 of the first wedge member 162, which is located away from the intermediate shielding member 20, is formed with an outer contour that is parallel to the waveguide 162b. However, if necessary, the outer contour of this second excess pad portion 162c-2 may be formed into an irregular shape that differs from the waveguide 162b.

As noted above, comparing Figures 9 and 11, the height dimension H2 of the first and second wedge members 162, 182 included in the high-temperature type is greater than the height dimension H1 of the first and second wedge members 162, 182 included in the standard type. This is effective in eliminating thermal problems in the flowmeter display 64; however, it has become apparent that the directionality of the ultrasonic waves weakens as the distance between the ultrasonic element 66 (68) and the piping 4 increases. It has been demonstrated that one effective way to solve this problem is to tape the ends of the first and second wedge members 162, 182 included in the high-temperature type that face the piping 4.

Figure 13 is a cross-sectional view of Figure 11 taken along the direction transverse to the pipe 4, illustrating the state in which the measurement head 62 is pressed against the mounting base member 60. As can be clearly seen from Figure 13, the first and second wedge members 162, 182 included in the high-temperature type have tapered ends 163, 183 on the metal pipe 4 side. This tapered shape reduces the end faces of the first and second wedge members 162, 182 that contact the metal pipe 4. This restricts the path through which ultrasonic signals can enter the fluid via the metal pipe 4, thereby maintaining high measurement accuracy. In addition, the tapered portions 163, 183 are surrounded by air. This prevents ultrasonic signals from entering from around the tapered portions 163, 183.

The measurement head member 62 transmits ultrasonic signals to the metal pipe 4 with directionality via the first and second wedge members 162, 182. By clarifying the directionality with the tapered portions 163, 183, the ultrasonic signals are prevented from spreading and entering the pipe 4. By clarifying the directionality, the effects of stray signals propagating within the metal pipe 4 can be reduced.

Therefore, it goes without saying that the ends of the first and second wedge members 162, 182 included in the standard type measurement head member 62A, not just the high-temperature type, can also be tapered portions 163, 183 on the pipe 4 side.

Figures 14 to 30 are diagrams illustrating multiple display examples DP-1 to DP-17 of the flowmeter display 64 included in the clamp-on ultrasonic flowmeter 6 in an ultrasonic flow detection device 12 consisting of a clamp-on ultrasonic flowmeter 6, a clamp-on concentration sensor 8, and a temperature sensor 10.

The flowmeter display 64 included in the clamp-on ultrasonic flowmeter 6 includes a flow port, multiport 1, and multiport 2. A measurement head member 62 is connected to the flow port, a temperature sensor 10 is connected to multiport 1, and a concentration sensor 8 is connected to multiport 2. The connection status of these multiple sensors is displayed by one display example DP-1 in Figure 14.

The display on the flowmeter display 64 can be used to perform various initial settings related to the sensor. Display example DP-2 in Figure 15 is one example. Display example DP-2 allows the flow direction of the fluid flowing through the pipe 4 to be set. "Towards the LED side" in DP-2 means one direction of the pipe 4, and the user can also select "From the LED side" as an alternative to "Towards the LED side." "From the LED side" means the other direction of the pipe 4. This may be displayed as an image or pictograph. In other words, the user can selectively specify one of two flow directions through the pipe 4 and have this displayed. Display example DP-2 allows the user to specify the diameter of the pipe 4 and the type of pipe 4 by selecting from metal, resin, etc.

The ultrasonic flow rate detection device 12 has the function of calculating the amount of heat using the flow rate sensor, i.e., the measurement head member 62, and the temperature sensor 10. The user can enable or disable this heat rate calculation function using the display example DP-3 in Figure 16.

The ultrasonic flow detection device 12 allows you to select the units for the detected flow rate and concentration using display example DP-4 (Figure 17). Flow rate units such as L/min and cubic meters/hour can be displayed sequentially as configurable options. Concentration units such as %, Brix% can be displayed sequentially as alternative options. The user can set what each of the multiple display channels on the flow meter display 64 will display using display example DP-5 shown in Figure 18.

Figure 19 shows display example DP-6, a menu screen that can be displayed on the flowmeter display 64. This menu screen (display example DP-6) displays four menus: current value, history, settings, and status. Figure 20 shows an example of the display on the flowmeter display 64 when current value is selected. Display example DP-7 in Figure 20 displays the flow rate during operation. In Figure 20, "73.9" means the current flow rate (73.9 L/min) of the fluid flowing through pipe 4. In Figure 20, "80.0" in [1] means the maximum value of the fluid flowing through pipe 4, and "72.0" in [2] means the minimum value of the fluid flowing through pipe 4. In other words, display example DP-7 shows that during operation, not only the current value but also the maximum and minimum values can be displayed on a single screen.

Display example DP-8 in Figure 21 is an example of the temperature of the fluid flowing through pipe 4 during operation. "21.5°C" is the temperature of pipe 4 detected during operation, and this temperature is equal to the temperature of the fluid flowing through pipe 4. "20.0" below indicates the temperature threshold. Display example DP-9 in Figure 22 shows the concentration of the fluid flowing through pipe 4 during operation. "7.5 Brix%" displayed in display example DP-9 indicates the concentration during operation. "2.5" below indicates the concentration threshold.

During operation, the flowmeter display 64 may display the flow rate, temperature, and concentration on separate, independent screens, or may have a multi-display screen that displays these values in a list, as shown in example display DP-10 in Figure 23. In example display DP-10 in Figure 23, "19.7°C" is the temperature measured by the measurement head member 62, but in addition, the temperature measured by the temperature sensor 10, "49.3°C," is also displayed in example display DP-10. "7.9 Brix%" is the concentration.

Display example DP-11 in Figure 24 is the menu screen mentioned above, and when the "Current Value" menu is selected, the current values exemplified in Figures 20 to 22 are displayed. When the "History" menu is selected, the first time series graph display example DP-12 (curve graph display) in Figure 25 or the time series display example DP-13 (bar graph display) in Figure 26 can be selectively displayed. In the graph displays in Figures 25 and 26, the horizontal axis scale can be changed to 1 year, 1 month, 1 week, 1 day, 1 hour, or 10 minutes, and the graph displays in Figures 25 and 26 can be executed with the horizontal axis scale set by the user.

Selecting the "Settings" menu item on the menu screen of menu display example DP-11 in Figure 24 switches to the screen of display example DP-14 in Figure 27. This display example DP-14 displays a list of several categorized setting items, from which the user can select. Display example DP-14 (Figure 27) includes the setting items "Input/Output Settings," "Detection Settings," "System Settings," "Convenient Functions," and "Initialization." The "Detection Settings" item is the setting for each sensor connected to the flowmeter display 64. The "System Settings" item allows you to change the settings of the flowmeter display 64, such as the indicator light status, screen orientation, language, enable/disable log data recording, and key lock method. The "Convenient Functions" item allows you to issue commands for each sensor, such as flow rate zero point adjustment, concentration teaching, and integrated flow rate reset. The "Initialization" item allows you to restart, initialize settings, clear history data, initialize input/output settings, and perform a complete initialization.

Display example DP-15 in Figure 28 is an example of a display related to the settings of the concentration sensor 8. In the concentration sensor 8 settings, you can change the response time, display resolution, temperature characteristic correction value, etc., as well as turn on/off the stability alarm that outputs an alarm when instability occurs, and switch the dry water detection sensitivity, which is the sensitivity for detecting dry water, a state in which there is no fluid, between OFF/low/medium/high.

The display example DP-16 in Figure 29 is an example of a display related to the settings of the measurement head component 62 (flow sensor). The settings for the measurement head component 62 (flow sensor) include selectable response time, display resolution, hysteresis, zero cutoff flow rate, flow direction (toward/from the LED), pipe material (metal/resin), and pipe diameter. Additionally, the timing for bubble detection can be changed. In the example DP-16 shown, "1 second" is set, and bubbles are detected every second using a bubble detection principle such as the Doppler method. The measurement head component 62 (flow sensor) has two settings: the first level (level) allows the above settings, and the second level (level) allows more detailed, complex settings for experienced users. When Pro mode is turned on, the Pro mode display changes to professional settings, with the detailed settings displayed below.

The display example DP-17 in Figure 30 is an example of what appears when the Pro mode display is selected. The Pro mode settings for the measurement head member 62 (flow sensor) allow you to set the flow detection mode, pipe outer diameter input, pipe thickness input, pipe sound velocity input, and kinematic viscosity input. The Pro settings set in this "Pro mode" item are items that, once entered during initial setup, are rarely changed during subsequent flow measurement. Furthermore, because changing the settings incorrectly can affect the detection accuracy of the flow sensor, settings are changed at a separate level to prevent unnecessary changes. The "Flow Detection Mode" item can be changed between hybrid, transit time difference, and Doppler. Hybrid is a method that combines transit time difference and Doppler. The Doppler method is resistant to air bubbles, but cannot be measured without air bubbles. Transit time difference cannot be measured if there are air bubbles in the fluid. Hybrid combines both methods.

2 Coolant storage tank 4 Piping (towards machine tool)
6 Integrated clamp-on flowmeter 60 Mounting base member 62 Measuring head member 62A Standard type 62B High temperature type 64 Flowmeter display 64a Display unit 66 First ultrasonic element 68 Second ultrasonic element 70 Element holding unit 8 Concentration sensor 10 Temperature sensor 12 Ultrasonic flow detection device 16 First ultrasonic transmission unit 162 First wedge member (first element holding unit)
162a: First element coupling surface; 162b: Waveguide of first wedge member; 162c: Extra pad; 162e: Inclined surface facing the intermediate ultrasonic shielding member; 164: First couplant; 18: Second ultrasonic transmission section; 182: Second wedge member (second element holding section);
182a: Second element coupling surface 182b: Waveguide of second wedge material 184: Second couplant 20: Intermediate ultrasonic shielding member

Claims (13)

An ultrasonic flow meter for measuring the flow rate of a fluid flowing through a pipe,
a first ultrasonic element that transmits and receives ultrasonic waves;
a second ultrasonic element that transmits and receives ultrasonic waves;
a first method for calculating a flow rate of the fluid in the pipe based on an output signal of the first ultrasonic element;
a second method for calculating the flow rate based on output signals of the first and second ultrasonic elements; and
an element holding portion that holds the first and second ultrasonic elements;
a mounting fixture that holds the element holding part and is detachably attached to the outer surface of the pipe,
The element holding unit is
a first element holding portion that supports the first ultrasonic element so as to be acoustically coupled to the first ultrasonic element;
a second element holding portion that supports the second ultrasonic element so as to be acoustically coupled to the second ultrasonic element;
Including,
the first element holding portion forms a first waveguide through which ultrasonic waves transmitted by the first ultrasonic element are guided into the fluid in the piping through the first element holding portion;
the second element holding portion forms a second waveguide through which ultrasonic waves propagated through the fluid in the piping pass through the second element holding portion and are received by the second ultrasonic element;
an ultrasonic flowmeter, wherein the first element holding portion is positioned so that ultrasonic waves transmitted from the first ultrasonic element are reflected by a surface of the first element holding portion facing the second element holding portion, and the reflected waves are not input to the first ultrasonic element. an intermediate ultrasonic shielding member that shields propagation of an ultrasonic signal between the first ultrasonic element and the second ultrasonic element is provided between the first element holding portion coupled to the first ultrasonic element and the second element holding portion coupled to the second ultrasonic element;
2. The ultrasonic flowmeter according to claim 1, wherein a surface of the first element holding portion that faces the second element holding portion is oriented in a direction inclined with respect to the intermediate ultrasonic shielding member. An ultrasonic flowmeter according to claim 1 or 2, wherein the surface of the first element holder facing the second element holder is inclined in a plan view with respect to the surface of the first ultrasonic element facing in the direction in which the second ultrasonic element is located. An ultrasonic flowmeter according to any one of claims 1 to 3, wherein the first method is a Doppler method and the second method is a transit time method. the ultrasonic flowmeter has a standard type and a high-temperature type depending on the difference in height between the first and second element holding portions,
5. The ultrasonic flowmeter according to claim 1, wherein height dimensions of the first and second element holding portions included in the high-temperature type are greater than height dimensions of the first and second element holding portions included in the standard type. The first element holding portion has a cross section perpendicular to the piping direction,
The width of the portion coupled to the pipe side is smaller than the width of the portion coupled to the first ultrasonic element,
The second element holding portion has a cross section perpendicular to the piping direction,
6. The ultrasonic flowmeter according to claim 1, wherein a width of the portion coupled to the pipe side is smaller than a width of the portion coupled to the second ultrasonic element. a portion that tapers toward a portion that couples with the first ultrasonic element;
The ultrasonic flow meter of claim 6 , further comprising a portion that tapers toward a portion that couples with the second ultrasonic element. The ultrasonic flowmeter described in any one of claims 1 to 7, further comprising a metal protective cover that houses and covers the first ultrasonic element, the second ultrasonic element, the calculation unit, and the element holding unit. the element holder incorporates the first element holder and the second element holder while being spaced apart from each other along a first direction, and has a pipe coupling surface for acoustically coupling with the pipe;
3. The ultrasonic flowmeter according to claim 1, wherein the first ultrasonic element and the second ultrasonic element are each disposed at an angle with respect to the first direction toward the pipe coupling surface. an intermediate ultrasonic shielding member that is housed inside the element holding portion and is disposed between the first element holding portion and the second element holding portion to shield propagation of an ultrasonic signal between the first ultrasonic element and the second ultrasonic element;
a first couplant disposed adjacent to the first element holder, constituting a part of the pipe coupling surface, and providing an acoustic coupling effect under a compressive force;
a second couplant disposed adjacent to the second element holder, constituting a part of the pipe coupling surface, and providing an acoustic coupling effect under a compressive force;
The ultrasonic flow meter of claim 9 further comprising: a circuit board that is housed inside the element holding portion and is arranged on a surface side of the first and second element holding portions that faces the pipe connection surface, and that controls transmission and reception of the first and second ultrasonic elements and that is capable of calculating the flow rate by computing detection data; and
a flow meter indicator that is detachably installed on a surface of the element holding part that faces the pipe connection surface, and that has a display part that displays the flow rate calculated by the calculation part, an operation part that makes various settings on the display part, and a first indicator light;
a second indicator light disposed on a surface of the element holding portion opposite to the pipe coupling surface;
The ultrasonic flow meter of claim 9 further comprising: the element holder incorporates the first element holder and the second element holder and has a pipe coupling surface for acoustically coupling with the pipe;
the first ultrasonic element is arranged to form the first waveguide toward the pipe coupling surface in the first element holding portion,
the first element holding portion has an excess pad portion that is adjacent to the first waveguide and forms a surface facing the second element holding portion;
3. The ultrasonic flowmeter according to claim 1 or 2. The ultrasonic transducer further includes a circuit board that controls transmission and reception of the first and second ultrasonic elements and configures the calculation unit that can calculate the flow rate by calculating detection data,
the height dimensions of the first and second element holding portions are set to dimensions that prevent thermal deterioration of the circuit board;
5. The ultrasonic flowmeter according to claim 1.