JP4045974B2 - Flow measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flow rate measuring device for measuring a flow rate of gas or the like.
[0002]
[Prior art]
In this type of conventional flow rate measuring device, a flow rate detecting means comprising a pair of ultrasonic transducers and the like is arranged in a measurement flow path in which a fluid supply path is connected upstream and a fluid outflow path is connected downstream. .
[0003]
Then, the flow velocity of the fluid flowing through the measurement flow path is measured by the flow velocity detection means, and the flow rate is calculated based on the measured flow velocity (Patent Document 1).
[0004]
[Patent Document 1]
JP-A-9-18591
[Problems to be solved by the invention]
However, in the conventional flow rate measuring device, since the flow path and the measurement unit are integrated, a measure for improving accuracy, for example, high-precision processing is difficult, and the flow path specification when the measurement specification changes, etc. Change was not easy.
[0006]
The present invention solves such a conventional problem, and it is possible to realize high accuracy of measurement by rationally configuring the measurement unit and to reliably respond to specification changes and the like. It is a thing.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a measurement unit in which a fluid supply path is connected to the upstream side and a fluid outflow path is connected to the downstream side, and is included in the measurement unit. A flow path body, an ultrasonic transducer disposed upstream and downstream in the fluid flow direction so that the ultrasonic wave obliquely crosses the fluid flowing through the measurement flow path body, and an output of the ultrasonic transducer comprising a calculating means for calculating the amount of fluid flowing through the original to the measurement flow path body, the ultrasonic transducer is thereby deployed measuring section side, the ultrasonic transmission and reception on the side walls of the measurement flow path body An opening is formed facing the ultrasonic wave transmission / reception direction of the wave transducer, and positioning means are provided in the measurement section and the measurement flow path body so that the opening and the ultrasonic wave transmission / reception direction of the ultrasonic wave transducer coincide with each other. as hereinbefore, by processing the measurement flow path body alone, but capable of promoting its high accuracy
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes a measurement unit in which a fluid supply path is connected to the upstream side and a fluid outflow path is connected to the downstream side; the measurement unit is included in the measurement unit; An ultrasonic transducer disposed upstream and downstream in the fluid flow direction so that the ultrasonic wave obliquely crosses the fluid flowing through the path body, and a measurement channel body based on the output of the ultrasonic transducer Computing means for computing the amount of flowing fluid, and the ultrasonic transducer is arranged on the measurement section side, and the ultrasonic transducer in the direction of ultrasonic transmission / reception is provided on the side wall of the measurement channel body. An opening is formed to face each other, and positioning means is provided in the measurement section and the measurement flow path body so that the opening and the ultrasonic transmission / reception direction of the ultrasonic transducer coincide with each other.
[0009]
Since the measurement channel body is configured separately from the measurement unit in this way, the measurement channel body can be processed independently to promote higher accuracy, and the specification can be easily changed. It becomes.
[0010]
And since the ultrasonic transducer is arrange | positioned at the measurement part side, handling of a measurement flow path body becomes still easier.
[0011]
As the positioning means, for example, it is conceivable to provide unevenness that is phase-engaged with the measurement channel body and the measurement unit.
[0012]
In addition, if the fluid supply path is connected to the measurement section at least so as to overlap the measurement flow path body, and the fluid from the fluid supply path to the measurement flow path body is meandering and flowing, the measurement flow path body is stable. It becomes a flow form and enables more accurate flow rate measurement .
[0013]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
(Example 1)
1 and 2, the measuring unit 1 has a rectangular shape with a rectangular cross section. A fluid supply path 3 is connected to the upstream chamber 2 and a fluid outflow path 5 is connected to the downstream chamber 4 at substantially right angles. It is set in the shape.
[0015]
The fluid supply path 3 has a valve seat 8 that is opened and closed by a valve body 7 that is linked to a driving unit 6 such as an electromagnetic device or a stepping motor. The introduction path 9 downstream of the valve seat 8 and connected to the upstream chamber 2 of the previous measuring unit 1 is rectangular.
[0016]
Reference numeral 10 denotes an inflow port of the fluid supply path 3, 11 denotes a lead-out path of the fluid outflow path 5 formed in a rectangular shape, and 12 denotes an outflow port.
[0017]
As shown in FIG. 2, the measuring unit 1 is arranged so that at least a pair of ultrasonic transducers 13 and 14 constituting the flow velocity detecting means are opposed to each other diagonally.
[0018]
A rectangular measurement channel body 15 included in the measurement unit 1 and having a cross-sectional rectangular shape separately from the measurement unit 1 has openings 16 a and 16 b facing the ultrasonic transducers 13 and 14. is there.
[0019]
The openings 16a and 16b are covered with ultrasonically permeable porous materials 17a and 17b made of a metal net, punching metal, or the like so that fluid does not enter the direction of the ultrasonic transducer 13 (in the figure, upstream). This is representatively shown to be opposite to the ultrasonic transducer 13 on the side).
[0020]
In addition, by providing projections and recesses 18 and 19 that engage with each other between the measurement unit 1 and the measurement channel body 15, the measurement channel body 15 is positioned with respect to the measurement unit 1. The openings 16a and 16b of the part 1 are surely opposed to the ultrasonic transducers 13 and 14.
[0021]
Further, each end portion of the measurement flow path body 15 extends to a position facing the introduction path 9 of the fluid supply path 3 and the lead-out path 11 of the fluid outflow path 5. The introduced fluid flows as if detouring and reaches the measurement flow path body 15, and the fluid from the measurement flow path body 15 flows as if detouring and reaches the lead-out path 11 of the fluid outflow path 5.
[0022]
The bypass flow form on the fluid supply side is effective in suppressing fluid drift and the like. In addition, the detour flow form on the fluid outflow side is effective in suppressing the uneven flow at the time of fluid backflow caused by the occurrence of pulsation.
[0023]
The ultrasonic propagation time between the ultrasonic transducers 13 and 14 is measured by the measurement control means 20 (details will be described later), and the calculation means 21 calculates the flow rate based on the result. These measurement control means 20 and calculation means 21 are driven by a battery power source 22 such as a lithium battery.
[0024]
Further, the drive unit 6, the measurement control unit 20, the calculation unit 21, etc. of the valve body 7 are arranged in a portion surrounded by a U-shaped flow path constituent material, and are integrated in a compact manner as a whole. Yes.
[0025]
In the above configuration, if the flow rate measurement operation of the fluid is described, first, ultrasonic waves are generated from the ultrasonic transducer 13 on the upstream side in the forward direction with the flow and as it crosses diagonally.
[0026]
The ultrasonic wave propagates through the fluid flow at the speed of sound, is detected by the ultrasonic transducer 14 on the downstream side, is converted into an electric signal, the signal is amplified by the amplifier of the measurement control means 20, and the comparator Compared with the reference signal, it is detected that an ultrasonic signal has been received.
[0027]
The change of the comparison signal is sent to the repetition means and transmitted again by the trigger means through the delay means.
[0028]
The number of repetitions ends with the number set by the number setting means. The time measuring means resets the timer when the first trigger signal is transmitted, and measures the time until the end of the repetition.
[0029]
When the transmission of the ultrasonic waves from the upstream to the downstream ends, the transmission / reception direction is switched by the switching means.
[0030]
Transmission is performed from the downstream ultrasonic transducer 14 toward the upstream ultrasonic transducer 13, that is, from the downstream to the upstream. The transmission is repeated in the same manner as described above, and the time is counted. The From the time difference from the upstream to the downstream and the time difference from the downstream to the upstream, the calculation means 21 calculates the flow rate by an arithmetic expression such as a reciprocal difference in propagation time.
[0031]
The valve body 7 is closed when the fluid flow is abnormal or when an earthquake occurs.
[0032]
By the way, as described above, since the measurement channel body 15 is configured separately from the measurement unit 1, the measurement channel body 15 can be processed independently, and a high-precision measurement unit can be easily obtained. It is also possible to deal with changes in specifications and the like.
[0033]
A fluid flow form to the measurement channel body 15 will be described. First, the fluid flowing into the fluid supply path 3 from the inlet 10 flows from the valve seat 8 into the introduction path 9 and further into the upstream chamber 2 of the measuring unit 1.
[0034]
Since one end of the measurement channel body 15 is located in the upstream chamber 2 in a rushing state, the fluid flowing into the upstream chamber 2 flows in a detouring flow and flows into the measurement channel body 15. Become.
[0035]
Therefore, even if there is a drift in the upstream, it is corrected by the detour, and as a result, the fluid flowing through the measurement flow path body 15 becomes stable and enables accurate flow velocity measurement.
[0036]
(Example 2)
FIG. 3 shows an embodiment in which the fluid flowing through the measurement channel body 15 is made more stable.
[0037]
The introduction path 9 of the fluid supply path 3 is connected to the measurement section 1 so as to overlap the measurement flow path body 15 at a predetermined distance D from the inflow side end of the measurement flow path body 15. Yes.
[0038]
Therefore, since the fluid from the introduction path 9 flows into the measurement flow path body 15 in a meandering manner, a reliable rectifying action is exerted against the upstream drift and the like.
[0039]
Of course, the same structure is adopted also on the outflow side of the measurement flow path body 15, so that it is possible to reliably cope with the occurrence of the backflow.
[0040]
FIG. 4 shows the turbulent flow preventing portions 23 and 24 formed such that the opening edges at both ends of the measurement channel body 15 are arcuate. When the fluid flows to the measurement channel body 15, the fluid flows smoothly, The vortex is not generated.
[0041]
(Example 3)
FIG. 5 shows an example in which positioning means for the measurement channel body 15 is provided between both outer side portions of the measurement channel body 15 and both inner side portions of the measurement unit 1.
[0042]
That is, the concave and convex portions 18 and 19 that engage with the front and rear sides of the inner side of the measurement unit 1 and the front and rear sides of the outer side of the measurement flow channel body 15 are formed, and the measurement flow channel body 15 is accurately arranged in the measurement unit 1 I have to.
[0043]
In each of the above-described embodiments, a measure is taken to stabilize the fluid flow to the measurement flow path body 15 even when backflow occurs. However, if there is no backflow, the fluid flow stability is stable only on the upstream side of the measurement flow path body 15. It is conceivable to take measures to make it easier.
[0044]
In addition, an ultrasonic transducer has been taken as an example of the flow velocity detection means, but the spirit of the present invention is not limited to the specific detection configuration. There may be various things used.
[0045]
Further, in each of the above embodiments, the flow velocity detecting means is arranged in the measuring section, but it may be arranged on the measurement flow path body side to constitute a kind of unit body.
[0046]
【The invention's effect】
As described above, the present invention includes a measurement unit in which a fluid supply path is connected to the upstream side and a fluid outflow path is connected to the downstream side, the measurement unit included in the measurement unit, , Measurement based on the ultrasonic transducers arranged upstream and downstream of the flow direction of the fluid so that the ultrasonic wave obliquely crosses the fluid flowing through the measurement channel body, and the output of the ultrasonic transducer Computing means for computing the amount of fluid flowing through the flow path body, the ultrasonic transducer is disposed on the measurement unit side, and an ultrasonic wave of the ultrasonic transducer is disposed on a side wall of the measurement flow path body. An opening is formed facing the sound wave transmission / reception direction, and positioning means are provided in the measurement unit and the measurement flow path body so that the opening and the ultrasonic wave transmission / reception direction of the ultrasonic wave transmitter / receiver coincide with each other. .
[0047]
As a result, the measurement flow path body can be processed independently, and the high accuracy can be promoted, and the specification can be easily changed.
[Brief description of the drawings]
1 is a longitudinal sectional view of a flow rate measuring device according to an embodiment of the present invention. FIG. 2 is a transverse sectional view of the flow rate measuring device. FIG. 3 is a longitudinal sectional view of a flow rate measuring device according to another embodiment of the present invention. FIG. 4 is a cross-sectional view of a measurement flow path body according to another embodiment of the present invention. FIG. 5 is a cross-sectional view of a flow rate measuring apparatus according to another embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Measurement part 3 Fluid supply path 5 Fluid outflow path 13, 14 Flow velocity detection means (ultrasonic transducer)
15 Measurement channel body 18, 19 Concavity and convexity

Claims (3)

A measurement section having a fluid supply path connected to the upstream side and a fluid outflow path connected to the downstream side, and a measurement flow path body that is included in the measurement section and separate from the measurement section, and flows through the measurement flow path body Ultrasonic transducers arranged upstream and downstream in the fluid flow direction so that the ultrasonic waves cross diagonally across the fluid, and the amount of fluid flowing through the measurement channel body based on the output of the ultrasonic transducers And the ultrasonic transducer is disposed on the measurement unit side, and the side wall of the measurement channel body is opened facing the ultrasonic transmission / reception direction of the ultrasonic transducer. The flow rate measuring device is further provided with positioning means in the measurement section and the measurement flow path body so that the opening and the ultrasonic transmission / reception direction of the ultrasonic transducer coincide with each other . The flow rate measuring device according to claim 1 , wherein the measuring unit and the measurement flow path body are provided with unevenness that is phase-engaged to provide positioning means . 2. The flow rate measuring device according to claim 1, wherein at least the fluid supply path is connected to the measurement section so as to overlap with the measurement flow path body, and fluid flows from the fluid supply path to the measurement flow path body after meandering .

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