JP2003344133A - Flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in the trouble and the time required in the inspection work that the inspection work is troublesome because the flowmeter must be disassembled and taken off from the piping to see the inside of a flow passage, in confirming the unstable measurement due to breakdown or a foreign body; and that the re-adjustment in the assembly after the inspection is required, and so forth. <P>SOLUTION: A transparent case main body 10, a flow passage 18 formed inside the transparent case main body, and a sensor 28 which is arranged so as to be facing to the inside of the flow passage, are provided. The visual recognition whether the foreign body is stuck to the sensor or not can be performed without taking off the flowmeter from the piping and without disassembling the flowmeter. Thus, the inspection work is simplified. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter.

[0002]

2. Description of the Related Art As a conventional flow meter, Japanese Patent Laid-Open No. 11-2
There is one disclosed in Japanese Patent No. 30803. As shown in FIG. 4, in this flowmeter, a circuit board 3 is installed on an upper part of a case body 2 in which a flow path 1 is formed, and a wall 2 defining the flow path 1 is provided.
From the hole 8 formed in a to the micro flow sensor 4 (hereinafter,
(Abbreviated as a sensor) is exposed in the flow path 1, and the lead wire 4a of the sensor is led to the circuit board 3. Further, this flow meter is provided with a rectifying section 6 in which a plurality of mesh plates are arranged at intervals at the inlet 5 of the flow path 1. And
In this flow meter, the fluid flowing from the inlet port 5 is made a laminar flow in the rectifying unit 6 and is guided to the sensor 4, where the flow rate is measured.

[0003]

Since the conventional flowmeter is constructed as described above, the net plate of the rectifying section 6 can trap foreign matters and the like to some extent. However, it is difficult to capture a minute foreign substance, and the foreign substance that has entered the flow path 1 may adhere to the sensor 4 or the like. In that case, the measurement becomes unstable.

When the measurement becomes unstable, it is not possible to determine whether the cause is that a foreign substance adheres to the sensor 4 or an electrical failure of other parts. When a foreign substance adheres to the sensor 4, the flow meter must be removed from the pipe each time, and the flow meter must be disassembled to look inside the flow path, so the inspection work is troublesome and readjustment is required after inspection and assembly. However, there is a problem that the inspection requires time and labor.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a flow meter capable of easily confirming measurement instability due to a failure or foreign matter.

[0006]

In the flowmeter according to the present invention, the case main body is formed of a transparent body so that the flow passage formed inside and the sensor arranged facing the flow passage can be visually recognized from the outside. It is a thing.

In the flow meter according to the present invention, the wall surface of the flow path facing the sensor is formed in a convex lens shape.

The flow channel in the flowmeter according to the present invention is provided with respect to a flow channel portion which communicates with the inlet port and the outlet port in a direction perpendicular to each other and a flow channel portion which communicates between the flow channel portions. And a flow path portion in a vertical direction.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a conceptual exploded perspective view of a flowmeter according to the present invention, FIG. 2 is a vertical sectional view thereof, and FIG. 3 is a sectional view taken along line AA in FIG.

As shown in FIG. 1, the flowmeter includes a case body 10 integrally formed of a transparent resin, a lid 11 whose one end is rotatably supported by the case body 10, and a case body 10. The circuit board 12 and the like attached to the.

The case body 10 is, as shown in FIG.
The upper part has a recess 13 that opens upward. A groove 15 opening upward is formed in a bottom wall 14 of the recess 13, and holes 16 and 17 extending vertically downward with respect to the groove 15 are formed in bottom surfaces of both ends of the groove 15. And
The width of the groove 15 is the same as the width of the holes 16 and 17, and the depth a of the groove 15 is set smaller than the gap b between the holes 16 and 17. These holes 16 and 17 are formed in the flow path portion 1 of the flow path 18.
8a, 18b, and the lower end portions of the holes 16, 17 are the inlet port 1 formed on the end surface of the case body 10.
9 and the outlet port 20 are vertically communicated with each other.

As shown in FIG. 2, the sensor 28 of the groove 15 is
An arcuate surface 21 projecting into the flow path portion 18c is formed on the bottom surface opposed to the arcuate surface 21, and an arcuate surface 22 projecting outward is formed on the outer surface of the case body 10 facing the arcuate surface 21. There is. The arcuate surfaces 21 and 22 form the double-sided convex lens 23. Further, as shown in FIG. 3, on the side wall of the groove 15 facing the sensor 28, arc-shaped surfaces 24, 24 projecting into the flow path portion 18c are formed, and along the periphery of the opening of the groove 15. Ribs 25 are formed.

On the other hand, the lid 11 has shafts 11a, 11a formed on one side of one end thereof, and the shafts 11a, 11a are inserted into holes 26a, 26a formed in the side walls 26, 26 of the recess 13 respectively. It is rotatably supported by the case body 10. At the tip of the lid body 11, a claw 11b is provided.
Are formed. Then, the lid 11 has the claw 11b.
Engages with the notch 26b formed in the side wall 26 of the recess 13 to close the opening of the recess 13.

The circuit board 12 is a ceramic board. A connector 27 and elements having various functions are mounted on the upper surface of the circuit board 12, and a central portion of the lower surface of the circuit board 12 is not shown. The micro flow sensor 28 is arranged by adhesion or the like via an electric path. The micro flow sensor 28 is, for example, a flow sensor in which a temperature measuring resistance element is arranged so as to sandwich a heater element.

As shown in FIG. 2, the circuit board 12 is mounted on the ribs 25 formed on the bottom wall 14 of the recess 13 and fixed to the bottom wall 14 of the recess 13 by the adhesive 29.

The circuit board 12 thus installed
Completely closes the opening of the groove 15 and forms the flow path portion 18c of the flow path 18 with the circuit board 12 as one wall surface. And
Micro flow sensor 28 fixed to the circuit board 12
Is located above the center of the lens 23, as shown in FIG. 2, and between the arcuate surfaces 24, 24, as shown in phantom in FIG.

Further, in this flow meter, the inlet port 19,
The outlet port 20 is formed by the metal pipe bodies 30 and 30 embedded in the case body 10. Female screws 31, 31 are formed on the inner peripheral surfaces of the metal pipe bodies 30, 30.

In the flowmeter thus constructed, as shown in FIG. 1, a female screw 31 of the inlet port 19 is screwed with a connector 33 of a hose 32 having a suction pad (not shown) at the tip. Then, the connector 35 of the hose 34 connected to a vacuum pump (not shown) or the like is screwed into the female screw 31 of the port 20. At that time, gaskets 36 and 36 are respectively interposed between the connector 33 and the case body 10 and between the connector 35 and the case body 10.

When the vacuum pump is operated, fluid such as air flows from the inlet port 19 to the flow passage portion 1 of the flow passage 18.
8a, and then the vacuum pump through the flow path portions 18c, 18b and the outlet port 20. At that time, the fluid is first biased in the flow path portion 18a. Then, a laminar flow is formed in the flow passage portion 18c having a shallow depth and a reduced flow passage cross-sectional area, and the flow is rectified by the narrowed portions by the arcuate surfaces 21, 24 and 24, and the sensor 28 measures, for example, the flow state of the fluid. To be done. The measured value is sent to a controller (not shown) via the connector 27, 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 something is sucked into the suction pad. Can be judged.

In this flow meter, since the flow passage of the flow passage portion 18a is formed perpendicular to the inlet port 19, the fluid flowing from the inlet port 19 hits the wall surface of the flow passage portion 18a and the flow is lopsided. (Decelerated). Therefore, when foreign matter is mixed in the fluid, the foreign matter is retained at the bottom portion B of the flow path portion 18a. Next, the fluid will flow into the flow passage portion 18c, but since the flow passage of the flow passage portion 18b is formed perpendicular to the flow passage of the flow passage portion 18a, the fluid flowing from the flow passage portion 18a Hits the wall surface of the flow path portion 18c, that is, the circuit board, and the flow is diverted (decelerated). Therefore, even if the fluid contains foreign matters, these foreign matters are retained at the bottom portion B of the flow passage portion 18a and the meeting portion (corner portion) C between the flow passage portion and the flow passage portion 18c. Similarly, the foreign matter contained in the fluid is retained at the meeting portion (corner) D between the flow passage portion 18c and the flow passage portion 18b and the bottom portion E of the flow passage portion 18b.

Therefore, this flow meter has an inlet port 1
Even if foreign matter is mixed in the fluid flowing in from 9, the foreign matter is retained at the bottom portion B of the flow passage portion 18a or the meeting portion (corner portion) C between the flow passage portion 18a and the flow passage portion 18b. Adhesion to the sensor 28 due to reaching 28 is prevented. Further, since the foreign matter mixed in the fluid is also captured at the meeting portion (corner) D between the flow passage portion 18b and the flow passage portion 18c and the bottom portion E of the flow passage portion 18c, the foreign matter passes through the outlet port 20. It is prevented from flowing into a suction pump or the like. According to this flow meter, even if the fluid flows in the opposite direction, that is, when the fluid flows in through the outlet port 20 and is discharged through the inlet port 19, foreign matter flows through the bottom E of the channel portion 18c and the channel portion 18b. Foreign matter is detected by the sensor 2 because it is supplemented at the meeting portion (corner) D with the road portion 18c.
Adhesion to the sensor 28 due to reaching 8 is prevented.

Since the case body 10 of this flowmeter is transparent, the state in which foreign matter adheres to the sensor 28 and the state in which foreign matter collects in the bottom portions B and D of the flow passage portions 18a and 18b and the corner portions C and E are shown. Can be seen from the outside. In particular, the state of the sensor 28 can be magnified and viewed through the lens 23.

Further, in this embodiment, the arcuate surfaces 21, 2 are formed.
Although the double-sided convex lens 23 is formed by 2, the single-sided convex lens may be formed by only one of the arcuate surfaces 21 and 22.

The material of the case body 10 may be any transparent resin, and for example, a highly transparent resin such as polycarbonate, acryl or polyethylene is preferable.

The flow meter according to the present invention can, of course, detect not only the above-described use mode but also a continuous flow rate (flow velocity) change of the fluid flowing through the flow path 18.

[0026]

As described above, according to the present invention, the case main body is formed of the transparent body so that the flow passage formed inside and the sensor arranged facing the flow passage can be visually recognized from the outside. It is possible to visually check whether or not foreign matter is attached to the sensor without disconnecting the flow meter from the pipe and disassembling the flow meter, and it is possible to simplify the inspection work.

According to the present invention, since the wall surface of the flow path facing the sensor is formed in the shape of a convex lens, it is possible to more easily visually recognize whether or not foreign matter is attached to the sensor.

According to the present invention, the flow passage portions communicating with the inlet port and the outlet port in the respective directions perpendicular to each other, and the flow passages in the direction perpendicular to the flow passage portions communicating between the flow passage portions. Since the flow path was composed of the road part,
There is an effect that it is possible to reduce foreign matter from adhering to the sensor as much as possible.

[Brief description of 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 vertical sectional view of the flow meter shown in FIG.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a vertical cross-sectional view showing a conventional small flow meter.

[Explanation of symbols]

10 Case body 11 lid 11a axis 11b nail 12 circuit board 13 recess 14 bottom wall 15 grooves 16,17 holes 18 channels 18a, 18b, 18c Flow path part 19, 20 ports 21,22 arc surface 23 lenses 24 arc surface 25 ribs 26 Side wall 26a hole 26b Notch 27 connectors 28 Micro Flow Sensor 29 Adhesive 30 tube 31 female screw 32 hose 33 connector 34 Hose 35 connector 36 gasket B, E bottom C, D corner

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Watanabe             2-12-19 Shibuya, Shibuya-ku, Tokyo Stock market             Takeyama F-term (reference) 2F035 EA00

Claims (3)

[Claims] 1. A flowmeter comprising a transparent case body, a flow channel formed in the transparent case body, and a sensor arranged so as to face the flow channel. 2. The flowmeter according to claim 1, wherein the wall surface of the flow path facing the sensor is formed in a convex lens shape. 3. The flow passage includes a flow passage portion that communicates with the inlet port and the outlet port in a direction perpendicular to each other, and a flow passage in a direction perpendicular to the flow passage portion that communicates between the flow passage portions. The flowmeter according to claim 1 or 2, which is constituted by a road portion.