JP4080247B2 - Flowmeter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flow meter, and more particularly to a flow channel structure.
[0002]
[Prior art]
As a conventional flow meter, there is one disclosed in JP-A-11-230803. As shown in FIG. 6, this flow meter has a flow channel 2 formed linearly in the case body 1 and a flow sensor (hereinafter referred to as a sensor) from a hole 8 formed in a wall 2a that defines the flow channel. (Abbreviated) 3 is placed in the flow path 2.
The flow meter includes a rectifying unit 5 in which a plurality of mesh plates 4 are arranged at intervals in the inlet port 6 of the flow path 2, and the fluid flowing from the inlet port 6 is converted into a laminar flow by the rectifying unit 5. 3 and the flow rate is measured there. The fluid measured by the sensor 3 is discharged from the outlet port 7 to the outside.
[0003]
[Problems to be solved by the invention]
As described above, the conventional flowmeter has a plurality of mesh plates 4 arranged at appropriate intervals as the rectifying unit 5, and the fluid flow is disturbed immediately after the mesh plate 4. It is necessary to install the sensor 3 with a certain distance. For this reason, there existed a subject that the length of the flow path 2 became long and the structure of flowmeter itself became large.
[0004]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a flow meter that is compact and can perform more stable measurement without providing a rectification unit using a mesh plate.
[0005]
[Means for Solving the Problems]
A flow meter according to the present invention includes a case main body forming a main body of the flow meter, an inlet port formed at one end of the case main body, and an outlet port formed at the other end of the case main body, In a flowmeter comprising a flow path formed as an outlet of a flow path and a sensor facing the flow path, the flow path is an inlet port, an outlet port, a flow path portion facing the sensor, and The first flow path portion whose height dimension perpendicular to the flow of the measurement fluid is a height dimension in which the flowing fluid is rectified by the viscosity of the fluid, and communicates with the bottom surface of one end of the first flow path portion, and the inlet Second flow path portion extending perpendicularly to the flow direction of the fluid to be measured flowing from the port The flow direction of the fluid to be measured communicated with the bottom surface of the other end of the first flow path portion and flowing to the outlet port A third channel portion extending perpendicularly to the second From the first bottom portion provided in the second flow path portion on the opposite side of the first flow path portion side from the merge portion of the path portion and the inlet port, from the merge portion of the third flow path portion and the outlet port The second bottom structure provided in the third flow path portion on the opposite side to the first flow path portion side is formed in communication .
[0006]
In the flow meter according to the present invention, an arcuate surface protruding in the flow path is formed on at least a part of the wall defining the first flow path portion .
[0007]
In the flow meter according to the present invention, the first flow path portion is formed substantially perpendicular to the upstream flow path portion .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
1 is a conceptual exploded perspective view of a flow meter according to the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is a sectional view taken along line A'-A 'in FIG. It is sectional drawing.
[0009]
As shown in FIG. 1, the flow meter includes a lid body 11 having one end rotatably supported on the case body 10, a circuit board 12 attached to the case body 10, and the like.
[0010]
As shown in FIG. 1, the case body 10 has a recess 13 that opens upward at the top. Grooves 15 that open upward are formed in the bottom wall 14 of the recess 13, and holes 16 and 17 that extend vertically downward with respect to the groove 15 are formed on the bottom surfaces of both ends of the groove 15. These holes 16 and 17 constitute flow channel portions 18a and 18b of the flow channel 18, and the groove 15 forms a flow channel portion 18c described later. The flow path portions 18a, 18b and 18c are formed to have the same width, and the height dimension a perpendicular to the fluid flow of the flow path portion 18c where the sensor is located is the gap b between the flow path portions 18a and 18b. Is set smaller than. The height dimension a is a height dimension in which the flowing fluid is rectified by the viscosity of the fluid, for example, 2 mm or less. The lower ends of the holes 16 and 17 communicate with the inlet port 19 and the outlet port 20 formed on the end surface of the case body 10 in a vertical manner. A rib 21 is formed along the same edge of the opening of the groove 15.
[0011]
On the other hand, the lid 11 has shafts 11a and 11a formed on the sides of one end, and the shafts 11a and 11a are inserted into holes 22a and 22a formed in the side walls 22 and 22 of the recess 13 to thereby insert the case body. 10 is supported so as to be rotatable. A claw 11 b is formed at the tip of the lid 11.
The lid 11 closes the opening of the recess 13 by engaging the claw 11 b with a notch 22 b formed in the side wall 22 of the recess 13.
[0012]
The circuit board 12 is a ceramic substrate, and a connector 23 and elements having various functions are mounted on the upper surface of the circuit board 12, and an electric circuit (not shown) is provided at the center of the lower surface of the circuit board 12. The sensor 24 connected to the connector 25 is disposed by bonding or the like.
This sensor 24 is, for example, a flow sensor in which a temperature measuring resistance element is arranged so as to sandwich a heater element.
[0013]
Then, as shown in FIG. 2, the circuit board 12 is placed on the rib 21 at the opening periphery of the groove 15 formed in the bottom wall 14 of the recess 13 and fixed to the bottom wall 14 of the recess 13 by the adhesive 25. Is done.
[0014]
The circuit board 12 installed in this manner completely closes the opening of the groove 15 and forms a flow path portion 18c of the flow path 18 with the groove. The sensor 24 fixed to the circuit board 12 is positioned facing the flow path portion 18c.
[0015]
In addition, the flow meter is formed by metal pipes 26 and 26 in which an inlet port 19 and an outlet port 20 are embedded in the case body 10. And the internal threads 27 and 27 are formed in the internal peripheral surface of this metal pipe bodies 26 and 26. As shown in FIG.
[0016]
As shown in FIG. 1, in the flow meter configured in this way, for example, a connector 29 of a hose 28 having a suction pad (not shown) or the like at its tip is screwed onto the female thread 27 of the inlet port 19. A connector 31 of a hose 30 connected to a female pump 27 of the outlet port 20 is connected to a vacuum pump (not shown) or the like.
At that time, gaskets 32 and 32 are interposed between the connector 29 and the case main body 10 and between the connector 31 and the case main body 10, respectively.
[0017]
When the vacuum pump is operated, a fluid, for example, air is sucked from the inlet port 19 into the flow path portion 18a of the flow path 18, and is sucked into the vacuum pump through the flow path portions 18c and 18b and the outlet port 20.
At that time, the fluid is first drifted in the flow path portion 18a. Next, a laminar flow is formed in the flow path portion 18c having a shallow depth and a reduced cross-sectional area of the flow path. The measured value is sent to a controller (not shown) via the connector 23, where the flow velocity value, that is, the flow rate is calculated.
For example, the flow rate is maximum when nothing is sucked into the suction pad, and the flow rate is almost zero when an object is sucked into the suction pad. Can be judged.
[0018]
In this flow meter, since the flow path of the flow path portion 18a is formed perpendicular to the flow path of the inlet port 19, the fluid flowing from the inlet port 19 strikes the wall surface of the flow path portion 18a and the flow is unevenly distributed. (Decelerate). Therefore, when foreign matter is mixed in the fluid, the foreign matter is retained at the bottom B of the flow path portion 18a.
Next, the fluid flows into the flow path portion 18c. Since the flow path of the flow path portion 18c is formed perpendicular to the flow path of the flow path portion 18a, the fluid flowing in from the flow path portion 18a. The flow is deviated (decelerated) against the wall surface of the flow path portion 18c, that is, the circuit board 12. Therefore, even if foreign matters are included in the fluid, the foreign matters are retained at the bottom portion B of the flow path portion 18a and the meeting portion (corner portion) C between the flow path portion and the flow path portion 18c.
Similarly, foreign matters contained in the fluid are retained at the meeting portion (corner portion) D between the flow path portion 18c and the flow path portion 18b and the bottom E of the flow path portion 18b.
[0019]
Since the upstream flow path and the downstream flow path of the flow meter are symmetrical with respect to the sensor 24, even if a fluid flows from the outlet port 20 toward the inlet port 19, the same as described above. The flow rate can be measured.
[0020]
Embodiment 2. FIG.
5 and 7 show a flow meter according to a second embodiment of the present invention. FIG. 5 is a longitudinal sectional view of the flow meter, FIG. 6 is a sectional view taken along line BB in FIG. 5, and FIG. It is B'-B 'sectional view taken on the line. In the illustrated flow meter, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0021]
This flow meter forms an arcuate surface 33 in which at least a part of the bottom wall defining the passage portion 18c where the sensor 24 is located protrudes into the flow path, and an arc shape in which a part of the side wall protrudes into the flow path. Surfaces 34 and 34 are formed.
For this reason, the flow path portion where the sensor 24 is located is narrowed down by the arcuate surfaces 33, 34, and 34 to have a small diameter.
[0022]
In this flow meter, the fluid flowing in from the inlet port 19 is first drifted (decelerated) in the flow path portion 18a and then further deviated (decelerated) in the flow path portion 18c. The fluid guided to the flow path portion 18c is rectified by the flow path portion constricted by the arcuate surfaces 33, 34, and 34, and the flow state of the fluid is measured by the sensor 24, for example.
[0023]
In this flow meter, since the cross-sectional area of the flow path portion 18c is made smaller than that of the flow path portion 18a, and the cross-sectional area is reduced by the arcuate surfaces 33, 34, 34, the fluid flowing therethrough is rectified. Can be measured.
Further, by causing the sensor 24 to protrude into the flow path portion 18c, the flow path is narrowed by the sensor 24, and a rectifying effect can be expected.
[0024]
In the second embodiment, the arc-shaped surfaces 33, 34, and 34 are formed on the bottom surface and the side wall of the groove 15, respectively, but the degree of rectification is reduced with any one of them, but the rectification effect is reduced. Can be expected.
[0025]
Of course, the flowmeter of the present invention can detect not only the above-described usage mode but also a continuous flow rate (flow velocity) change of the fluid flowing through the flow path 18.
[0026]
【The invention's effect】
As described above, according to the present invention, each of the case main body forming the main body of the flowmeter, the inlet port formed at one end of the case main body, and the outlet port formed at the other end of the case main body are flow paths. In the flowmeter provided with a flow path formed as an inlet of the flow path and an outlet of the flow path, and a sensor facing the flow path, the flow path is an inlet port, an outlet port, and a flow path portion facing the sensor. The first flow path portion having a height dimension perpendicular to the flow of the fluid to be measured is a height dimension in which the flowing fluid is rectified by the viscosity of the fluid, and communicates with the bottom surface of one end of the first flow path portion. , A second flow path portion extending perpendicularly to the flow direction of the fluid to be measured flowing from the inlet port, communicated with the bottom surface of the other end of the first flow path portion, and flowing to the outlet port Third flow path portion extending perpendicular to the fluid flow direction A first bottom provided in the second flow path portion on the opposite side of the first flow path portion side from the joining portion of the second flow path portion and the inlet port, the third flow path portion and the outlet port Since the structure of the second bottom portion provided in the third flow path portion on the opposite side of the first flow path portion side from the merged portion is formed in communication, the flow of fluid in the vicinity of the sensor is rectified, and Laminar flow can be achieved, and stable measurement results from the sensor can be compensated.
Further, even if foreign matters are included in the fluid, the foreign matters are retained at the first bottom portion of the second flow path portion and the second bottom portion of the third flow passage portion.
[0027]
According to this invention, since the arc-shaped surface protruding in the flow channel is formed on at least a part of the wall defining the first flow channel portion , the fluid is rectified on the arc-shaped surface and stable measurement is performed. There is an effect that the result is compensated.
[0028]
According to the present invention, since the first flow path portion is formed at a substantially right angle with respect to the upstream flow path portion , the fluid is drifted at the meeting portion of the flow path portion. Therefore, there is an effect that a stable fluid can be guided to the sensor, and a more stable measurement result is compensated.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view conceptually showing a flow meter according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of the flow meter shown in FIG.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
4 is a cross-sectional view taken along line A′-A ′ in FIG. 2;
FIG. 5 is a longitudinal sectional view of a flow meter according to a second embodiment of the present invention.
6 is a cross-sectional view taken along line BB in FIG.
7 is a cross-sectional view taken along line B′-B ′ in FIG.
FIG. 8 is a longitudinal sectional view showing a conventional small flow meter.
[Explanation of symbols]
10 Case body 11 Lid 11a Shaft 11b Claw 12 Circuit board 13 Recess 14 Bottom wall 15 Groove 16, 17 Hole 18 Channel 18a, 18b, 18c Channel portion 19, 20 Port 21 Rib 22 Side wall 22a Hole 22b Notch 23 Connector 24 Microflow sensor 25 Adhesive 26 Tube 27 Female thread 28 Hose 29 Connector 30 Hose 31 Connector 32 Gasket 33, 34 Arc surface

Claims (3)

A case body that forms the body of the flow meter, an inlet port formed at one end of the case body,
  The outlet port formed at the other end of the case body and the flow path formed as the inlet of the flow path and the outlet of the flow path, respectively;
  In a flow meter with a sensor facing the flow path,
  The flow path is as follows: ( a ) ~ ( g ) A flowmeter characterized in that the structure is formed in communication.
( a ) Entrance port
( b ) Exit port
( c ) A flow path portion facing the sensor, the first flow path portion having a height dimension perpendicular to the flow of the fluid to be measured as a height dimension in which the flowing fluid is rectified by the viscosity of the fluid
( d ) A second flow path portion that communicates with the bottom surface of one end of the first flow path portion and extends perpendicular to the flow direction of the fluid to be measured that flows from the inlet port.
( e ) A third flow path portion that communicates with the bottom surface of the other end of the first flow path portion and extends perpendicular to the flow direction of the fluid to be measured flowing to the outlet port
( f ) A first bottom provided in the second flow path portion on the side opposite to the first flow path portion side from the joining portion of the second flow path portion and the inlet port.
( g ) A second bottom provided in the third flow path portion on the side opposite to the first flow path portion side from the merged portion of the third flow path portion and the outlet port. 2. The flowmeter according to claim 1, wherein an arcuate surface protruding in the flow path is formed on at least a part of a wall defining the first flow path portion. The flowmeter according to claim 1 or 2, wherein the first flow path portion is formed substantially perpendicular to the upstream flow path portion.

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