JP2003194608A - Thermal type flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal type flowmeter with which stable measurement output can be obtained even when the measuring flowrate is large. <P>SOLUTION: A layered filter 50 in which a mesh sheet 51 with a mesh part 51M formed therein, a first shielding sheet 52 with a shielding part 52C formed therein, a second shielding sheet 53 with a shielding part 53C formed therein, and a third shielding sheets 54 with a shielding part 54C formed therein are optionally combined to be layered is attached to a flow passage space 44 formed in a body 41. The three layers of mesh parts 51M are arranged thereby between a main flow passage M and a sensor flow passage S, and a shielding wall 47 is constituted of the shielding parts 52C, 53C, 54C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal type flow meter for measuring a flow rate by using a heating wire. More specifically, the present invention relates to a thermal flow meter that stabilizes the measurement output by reducing the turbulence of the fluid generated in the flow path.

[0002]

2. Description of the Related Art Conventionally, as one of thermal type flow meters for measuring a flow rate using a heat wire, there is one which uses a measuring chip manufactured by a semiconductor micromachining processing technique as a sensor section. As this type of thermal flow meter, for example,
Examples include those shown in FIG. The thermal type flow meter 1 of FIG.
In 01, the fluid to be measured that has flowed into the inlet port 102 is rectified by the rectifying mechanism 103, and then the measurement flow path 1
Through the outlet port 105 via 04,
In order to measure the flow rate of the fluid to be measured, the measurement chip 111 connected to the electric circuit 106 is exposed in the measurement channel 104.

Here, as shown in FIG. 24, the measuring chip 111 includes a silicon chip 116 in which an upstream temperature sensor 112, a heater 113, a downstream temperature sensor 114, and an ambient temperature sensor 115 (the above-mentioned sensors 112 to 115).
(Corresponding to "heat rays") is subjected to processing technology of semiconductor micromachining.

In the thermal type flow meter 101, the six electrodes D1, D2, D in the measuring chip 111 of FIG.
3, 3, D4, D5, D6 are provided on the silicon chip 116,
Each of the upstream temperature sensor 112, the heater 113, the downstream temperature sensor 114, and the ambient temperature sensor 115 and the electric circuit 1
06 was connected by wire bonding (W in FIG. 23) using the six electrodes D1 to D6.

In such a thermal type flow meter 101,
When the fluid to be measured does not flow in the measurement flow path 104, the temperature distribution of the measurement chip 111 in FIG. 24 is symmetrical with respect to the heater 113. On the other hand, when the fluid to be measured is flowing in the measurement flow path 104, the temperature of the upstream temperature sensor 112 decreases and the temperature of the downstream temperature sensor 114 increases, so that FIG.
The symmetry of the temperature distribution of the measurement chip 111 of No. 4 collapses according to the flow rate of the fluid to be measured. At this time, the degree of this collapse appears as a difference in resistance value between the upstream temperature sensor 112 and the downstream temperature sensor 114.
Through 6, it is possible to measure the flow rate of the fluid to be measured.

Here, vacuum suction is used for handling during semiconductor chip mounting. And
The confirmation of adsorption has been conventionally performed by a pressure sensor.
However, in recent years, semiconductor chips have become smaller and smaller. For this reason, for example, in a 0.5 mm square chip, an adsorption orifice (nozzle) having a diameter of 0.5 mm or 0.3 mm is used. As a result, there was no difference in the pressure inside the orifice between when adsorbed and when not adsorbed, and it was not possible to confirm adsorption with the pressure sensor. Under such circumstances, it has been proposed that the suction confirmation be performed by detecting the flow rate of air flowing through the orifice.

[0007]

However, in the thermal type flow meter 101 shown in FIG. 23, the responsiveness (1-2
There was a problem that sec) was low. This is because the rectification mechanism 103 cannot eliminate the turbulent flow generated in the measurement flow path 104, and in order to prevent the influence of the turbulent flow from appearing in the output signal, the output signal is subjected to integration processing. It is thought to be from. Further, the thermal type flow meter 1 shown in FIG.
There was also a problem that 01 was too large to be used for confirmation of adsorption. Therefore, it was difficult to use the thermal type flow meter 101 for confirmation of adsorption.

Therefore, the applicant of the present application proposed a thermal flowmeter of high speed response (50 ms) and small size in Japanese Patent Application No. 2000-368801 in order to solve the problems of responsiveness and size. Since this thermal type flow meter is small and has excellent responsiveness, it was suitable for use in confirmation of adsorption. However, the thermal type flow meter proposed by the present applicant in Japanese Patent Application No. 2000-368801 has a problem that the influence of fluid turbulence in the flow channel increases as the measured flow rate increases. That is, when the measured flow rate increases, a new problem arises that the measurement output becomes unstable due to the turbulence of the fluid in the flow path. Therefore, Japanese Patent Application 2000-
Even with the thermal flow meter proposed in 368801, it was difficult to accurately confirm the adsorption.

Therefore, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a thermal type flow meter which can stably obtain a measurement output even when the measurement flow rate is large. It is an issue.

[0010]

The thermal type flow meter according to the present invention, which has been made to solve the above-mentioned problems, has a sensor flow path other than a sensor flow path in which a heating wire for measuring a flow rate is installed. In a thermal type flow meter with a bypass flow path for
A filter is provided between the bypass channel and the sensor channel.

In this thermal type flow meter, the fluid to be measured that has flowed into the flow meter is divided into a sensor channel in which a heating wire is installed and a bypass channel for the sensor channel. Then, based on the measurement principle using the heat ray, the flow rate of the fluid to be measured flowing through the sensor flow path, and by extension, the flow rate of the fluid to be measured flowing inside the thermal type flow meter is measured. The flow rate range is changed by changing the ratio of the fluid to be measured divided into the sensor flow passage and the bypass flow passage, specifically, changing the cross-sectional area of the bypass flow passage.

Therefore, when the measured flow rate increases, the flow rate of the fluid to be measured flowing through the bypass flow passage increases. Then, the flow of the fluid to be measured in the bypass channel is disturbed.
Then, under the influence of the turbulence of the flow of the fluid to be measured in the bypass channel, the flow of the fluid to be measured flowing in the sensor channel is also disturbed. As a result, the measurement output becomes unstable.

However, in this thermal type flow meter, a filter is provided between the bypass flow passage and the sensor flow passage. Therefore, the fluid to be measured flows into the sensor channel after passing through the filter. As a result, the flow of the fluid under measurement flowing into the sensor channel is adjusted. That is, even if the flow of the fluid to be measured flowing into the bypass flow channel is disturbed, the filter provided between the bypass flow channel and the sensor flow channel,
The flow of the fluid to be measured flowing into the sensor channel is regulated. Therefore, the measurement output is stable.

In the thermal type flow meter according to the present invention, it is preferable that the filter has a plurality of meshes laminated. Further, it is more preferable that the meshes are laminated via a spacer having a predetermined thickness.

By forming a filter by laminating a plurality of meshes, the fluid to be measured, whose flow has been extremely adjusted, can be poured into the sensor channel. This is because the fluid to be measured reduces the turbulence of the flow every time it passes through a plurality of meshes. Therefore, in order to obtain a greater rectifying effect, it is considered that it is better to stack the meshes at a predetermined interval rather than directly stacking them. Therefore, the mesh should be laminated via the spacer having a predetermined thickness.

Further, the thermal type flow meter according to the present invention is a thermal type flow meter having a bypass channel for the sensor channel in addition to the sensor channel in which a heating wire for measuring the flow rate is installed. The present invention is characterized by having a rectifying mechanism that regulates the flow of fluid by forming a plurality of channels in the channel.

This thermal type flow meter has a rectifying mechanism which regulates the flow of fluid by forming a plurality of flow paths in the bypass flow path. Therefore, the flow of the fluid to be measured in the bypass flow path is adjusted. As a result, the flow of the fluid to be measured in the bypass channel does not adversely affect the flow of the fluid to be measured in the sensor channel. Therefore, the flow of the fluid to be measured flowing through the sensor channel is stable, and the measurement output is stable.

In the thermal type flow meter according to the present invention, it is preferable that the rectifying mechanism is a stack of thin plates having grooves. And, it is preferable that a plurality of grooves are formed in the thin plate. When forming a plurality of grooves, the grooves may be formed only on one side of the thin plate, or the grooves may be formed on both sides of the thin plate.

By laminating the thin plates having the grooves formed in this way, a plurality of flow paths are formed in the bypass flow path.
That is, the bypass channel is divided into a plurality of smaller channels. Then, the fluid to be measured flowing into the bypass passage flows in each groove. Therefore, the flow of the fluid under measurement flowing through the bypass flow path is adjusted. Further, by forming a plurality of grooves in one thin plate, more grooves can be provided in the laminated body, and a greater rectifying effect can be obtained.

Further, the rectifying mechanism may be a pin having a plurality of fins formed therein. By providing such a pin in the bypass channel, a plurality of channels are formed in the bypass channel. This is because the flow of the fluid to be measured flowing through the bypass channel is adjusted by this.

Further, the thermal type flow meter according to the present invention is a thermal type flow meter having a bypass flow path for the sensor flow path in addition to the sensor flow path in which a heating wire for measuring the flow rate is installed. It is characterized in that it has a shielding wall for allowing the fluid flowing out of the passage and the fluid flowing out of the bypass flow passage to join at the outlet flow passage formed in the body.

In this thermal type flow meter, since the shield plate is provided, the fluid to be measured flowing out from the sensor channel and the fluid to be measured flowing out from the bypass channel are formed in the outlet channel formed in the body. Join at. That is, the fluid to be measured outflowing from the sensor channel and the fluid to be measured outflowing from the bypass channel do not merge near the outlet of the sensor channel. As a result, the confluence point of the sensor flow channel and the bypass flow channel is kept away from the heating wire installed in the sensor flow channel. Therefore, the vortex of the flow generated at the confluence of the sensor channel and the bypass channel does not disturb the flow of the fluid to be measured in the sensor channel, and the measurement output is stable.

The shielding wall is large enough to keep the flow vortex generated at the confluence of the sensor flow passage and the bypass flow passage away from the confluence of the fluid to be measured in the sensor flow passage. All right. Therefore, in some cases, the tip of the shielding wall is located on the upper surface of the outlet channel,
It may be located in the center of the outlet channel.

Here, it is desirable that the outlet channel is not formed on the same straight line as the bypass channel. This is because when the outlet flow path is formed in this way, the above-described effect obtained by providing the shielding wall becomes greater.

It is desirable that the shield wall is formed by laminating a plurality of shield plates. By doing so, the above-mentioned groove can be formed in the shielding plate. That is, it is possible to form a shielding wall and also provide a rectifying mechanism in the bypass flow path. As a result, it is possible to more effectively suppress the influence of the turbulent flow of the fluid under measurement in the bypass passage on the measurement output when the measurement flow rate becomes large.

Since the above mesh is also formed as a thin plate, the above effect can be obtained by arranging the mesh on the upper side and the shielding plate (including the grooved one) on the lower side and laminating each of them. Demonstrated synergistically. That is,
Almost no turbulence occurs in the flow of the fluid to be measured in the sensor channel. Therefore, the measured output is very stable. In addition to the combinations illustrated here, synergistic effects can be obtained by arbitrarily combining the above-described inventions.

In the above-described thermal type flow meter according to the present invention, the bypass flow path has the substrate on the surface of which the electric circuit electrode for connecting to the electric circuit for performing the measurement principle using the heat wire is provided. The sensor channel is provided with a heat ray and a heat ray electrode connected to the heat ray, which is formed by closely contacting the side opening portion with the body in which the fluid flow passage having the opening portion is formed. It is desirable that the measurement chip be formed by a groove provided in at least one of the measurement chip and the substrate by mounting the measurement wire and the electric circuit electrode on the substrate by bonding them. In addition,
In the present specification, the “side surface opening” means an opening opened on a side surface of the body (in other words, a surface where the input / output port is not opened) and a surface on which the substrate is mounted.

In such a thermal type flow meter, the heating wire provided on the measuring chip is such that when the measuring chip is mounted on the substrate,
The heat wire electrode provided on the measurement chip and the electric circuit electrode provided on the surface of the substrate are bonded to each other to be connected to an electric circuit for performing the measurement principle using the heat wire. On the other hand, when the substrate is brought into close contact with the body, a bypass flow path is formed inside the body. At this time, since the groove is provided in the substrate or the measurement chip mounted on the substrate, the sensor channel for the bypass channel is also formed inside the body. As a result, it is possible to improve the responsiveness and downsize the thermal type flow meter.

Then, the fluid to be measured flowing inside the body is divided into the bypass flow passage and the sensor flow passage according to the cross-sectional area ratio of the bypass flow passage and the sensor flow passage. In this respect, since the heat ray provided on the measurement chip is in a state of being bridged to the sensor flow path, the flow rate of the fluid to be measured flowing through the sensor flow path by the electric circuit for performing the measurement principle using the heat ray, As a result, the flow rate of the fluid to be measured flowing inside the body can be measured. Then, as described above, no disturbance occurs in the flow of the fluid to be measured in the sensor channel, so that a very stable measurement output can be obtained. That is, this thermal type flow meter can output stable measurement results with a high-speed response.

Further, in the thermal type flow meter according to the present invention, a substrate having an electric circuit electrode connected to an electric circuit for performing a measurement principle using a heat wire on the surface is provided with a fluid flow having a side opening. A bypass channel formed by closely contacting the side opening with the body in which the outlet channel that is not collinear with the channel and the fluid channel is formed,
A measuring chip provided with a heating wire and a heating wire electrode connected to the heating wire is mounted on at least one of the measuring chip and the substrate by mounting the heating wire electrode and the electric circuit electrode on the substrate. A sensor flow channel formed by the groove, and, between the bypass flow channel and the sensor flow channel, a filter in which a plurality of meshes are stacked,
The present invention is characterized by having a shielding wall that joins the fluid flowing out from the sensor channel and the fluid flowing out from the bypass channel in the outlet channel. In particular, the shield wall is composed of a plurality of shield plates, and the filter and the shield wall are
It is desirable to have them in one stack.

In this thermal type flow meter, a substrate having an electric circuit electrode connected to an electric circuit for performing a measurement principle using a heat wire on a surface thereof is provided with a fluid passage having a side opening. A measuring chip provided with a bypass flow path formed by closely adhering to the body so as to close the side opening and a heating wire and a heating wire electrode connected to the heating wire are used for the heating wire electrode and the electric circuit. Since the sensor channel is formed by a groove provided on at least one of the measurement chip and the substrate by bonding the electrode and mounting it on the substrate, the response is improved and the size is reduced as described above. Is planned.

Further, this thermal type flow meter has a filter in which a plurality of meshes are laminated between the bypass flow passage and the sensor flow passage, a measured fluid flowing out from the sensor flow passage, and a measured fluid flowing out from the bypass flow passage. It has a shielding wall which joins the measurement fluid in the fluid flow path. As a result, the effect of providing the above mesh and the effect of providing the shielding wall are synergistically obtained. That is, the flow of the fluid to be measured in the sensor channel is hardly disturbed. Therefore, a very stable measurement output can be obtained. That is,
This thermal flow meter can output a stable measurement result with a high-speed response. Moreover, since the mesh (filter) and the shielding wall are provided in one laminated body, the thermal type flow meter does not become large in order to obtain a stable measurement output.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The most preferred embodiment of the thermal type flow meter of the present invention will be described in detail below with reference to the drawings. The thermal type flow meter according to the present embodiment is suitable for flow rate measurement that requires high-speed responsiveness and high sensitivity, for example, adsorption confirmation in handling during semiconductor chip mounting.

(First Embodiment) First, the first embodiment will be described. FIG. 1 shows a schematic configuration of the thermal type flow meter according to the first embodiment. As shown in FIG. 1, the thermal type flow meter 1 according to the present embodiment has a body 41, a sensor substrate 21, and a laminated filter 50. Then, with the laminated filter 50 mounted in the flow passage space 44 of the body 41, the sensor substrate 21 is sealed with the seal packing 48.
It is tightly attached to the body 41 via a screw. As a result, the sensor channel S and the main channel M that is a bypass channel for the sensor channel S are formed. That is,
The thermal type flow meter 1 according to the present embodiment is a thermal type flow meter including a sensor channel and a bypass channel.

As shown in FIGS. 2 and 3, the body 41 has a rectangular parallelepiped shape. 2 shows the body 41
3 is a plan view of FIG. 3, and FIG. 3 is a sectional view taken along line AA in FIG. An inlet port 42 and an outlet port 46 are formed on both end surfaces of the body 41. An inlet passage 43 is formed from the inlet port 42 toward the center of the body, and an outlet passage 45 is formed from the outlet port 46 toward the center of the body. The outlet channel 45 is
It is formed below the main flow path M. That is, the outlet channel and the main channel M are not arranged on the same straight line.

A flow passage space 44 for forming the main flow passage M and the sensor flow passage S is formed in the upper portion of the body 41. The cross section of the flow path space 44 has a shape in which both short sides of a rectangle are arcuate (semicircle), and an arcuate convex portion 44C is formed in the center thereof. Convex portion 44
C is for positioning the laminated filter 50 or a pin 80 (see the fourth embodiment) described later. Then, a part of the lower surface of the flow path space 44 is provided at the inlet flow path 43.
And communicates with the outlet channel 45. That is, the inlet passage 44 and the outlet passage 45 are communicated with the passage space 44 via the elbow portions 43A and 45A bent at 90 degrees. Further, a groove 49 for mounting the seal packing 48 is formed on the upper surface of the body 41 along the outer periphery of the flow path space 44.

The laminated filter 50, as shown in FIG.
A total of 11 sheets of four types of thin plates were laminated. That is, in order from the bottom, the mesh plate 51 and the first shielding plates 52, 5
2, 52, 52, the mesh plate 51, the second shield plate 53, the mesh plate 51, the second shield plate 53, the mesh plate 51, and the third shield plate 54 are laminated and adhered.
Each of these thin plates 51 to 54 has a thickness of 0.5 mm.
The following is the processing of each shape (micromachining processing) by etching. The projected shape of each of the thin plates 51 to 54 is the same as the cross-sectional shape of the flow channel space 44. As a result, the laminated filter 50 is mounted in the flow path space 44 without any gap.

Here, the individual thin plates will be described. First, the mesh plate 51 will be described with reference to FIGS. 5 and 6. 5A is a plan view of the mesh plate,
5B is a sectional view taken along line AA in FIG.
FIG. 6 is an enlarged view of the mesh portion. The mesh plate 51 is
As shown in FIG. 5, it is a thin plate having a thickness of 0.3 mm with mesh portions 51M formed at both ends. Mesh part 51M
Is a circular shape having a diameter of 4 mm, and as shown in FIG. 6, all the holes (diameter 0.2 mm) forming the mesh have a center-to-center distance of 0.27 mm. That is, the holes are formed so that the centers of the holes are the vertices of an equilateral triangle. In addition, the thickness of the mesh portion 51M is thinner than other portions as shown in FIG. 5B,
Its thickness is 0.05 to 0.1 mm. Further, a shielding portion 51C is formed on the mesh portion 51M (on the right side in FIG. 5) arranged on the outlet side.

Next, the first shield plate 52 will be described with reference to FIG. Note that FIG. 7A is a plan view of the first shielding plate, and FIG. 7B is a sectional view taken along line AA in FIG. 7A. As shown in FIG. 7, the first shield plate 52 is etched so as to leave the outer peripheral portion 52B and the shield portion 52C. As a result, the first shielding plate 52 has
A first opening 61 and a second opening 62 are formed.
The first shield plate 52 has a thickness of 0.5 mm.

Next, the second shielding plate 53 will be described with reference to FIG. Note that FIG. 8A is a plan view of the second shielding plate, and FIG. 8B is a cross-sectional view taken along the line AA in FIG. 8A. As shown in FIG. 8, the second shield plate 53 is etched so as to leave the outer peripheral portion 53B, the shield portion 53C, and the central portion 53D. That is, the first
An unprocessed part is left in the center of the shielding plate 52. As a result, the third opening 63 is formed in the second shielding plate 53.
A fourth opening 64 and a second opening 62 are formed. The thickness of the second shielding plate 53 is also 0.5 mm.

Finally, the third shield plate 54 will be described with reference to FIG. 9A is a plan view of the third shielding plate, and FIG. 9B is a sectional view taken along the line AA in FIG. 9A. As shown in FIG. 9, the third shielding plate 54 is etched so as to leave the outer peripheral portion 54B and the shielding portion 54C. That is, by not forming the fourth opening 64 in the second shielding plate 53, the shielding portion 5
3C and the central portion 53D are integrated to form a shielding portion 54C. Thereby, the third shielding plate 54
A third opening 63 and a second opening 62 are formed in the. The thickness of the third shielding plate 54 is also 0.5 mm.

Returning to FIG. 1, the mesh plate 51, the first shielding plate 52, the second shielding plate 53, and the third shielding plate 54 described above are combined and laminated and bonded as shown in FIG. By mounting the laminated filter 50 in the flow channel space 44, the main flow channel M is formed by the first opening 61 provided in the first shielding plate 52. Also, each thin plate 51-
The mesh portion 51, the first opening portion 61, and the third opening portion 63 provided in 54 make the inlet passage 43 and the main passage M
And the 1st connection flow path 5 which connects with the sensor flow path S is formed. Then, three layers of the mesh portion 51M are arranged between the main channel M and the sensor channel S. The spacing between the mesh portions 51M is 0.7 mm because the mesh plate 51 and the second shielding plate 53 play a role of spacers.
As a result, the fluid to be measured whose flow is adjusted every time it passes through each mesh portion 51M can be poured into the sensor flow path S. Further, the elbow portion 43A and the flow path space 44
The mesh part 51 is also arranged in the communication part with the (main flow path M).

Further, by mounting the laminated filter 50 in the flow path space 44, the mesh portion 51, the first opening portion 61, and the fourth opening portion 64 provided in each of the thin plates 51 to 54.
By which the main flow passage M and the outlet flow passage 45 are communicated with each other
The communication channel 6 is formed. Furthermore, each thin plate 51-5
The second opening 62 provided in the sensor passage S
A third communication flow path 7 is formed that connects the second flow path 45 and the outlet flow path 45. A shielding wall 47 is formed between the second communication channel 6 and the third communication channel 7. This shielding wall 47
Is constituted by the shielding portions 51C, 52C, 53C and 54C provided on the thin plates 51, 52, 53 and 54, respectively. Due to this shielding wall 47, the confluence point of the fluid under measurement flowing out of the sensor channel S and the fluid under measurement flowing out of the main channel M is at the elbow portion 45A and the channel space 4.
It is a communication part with 4. Further, as described above, the outlet flow passage 45 is arranged below the main flow passage M.

Therefore, the fluid to be measured flowing out from the sensor channel S and the fluid to be measured flowing out from the main channel M do not merge near the outlet of the sensor channel S. That is, the confluence point of the sensor channel S and the main channel M is kept away from the measurement chip 11 described later. Therefore, the vortex of the flow generated at the confluence of the sensor channel S and the main channel M does not disturb the flow of the fluid to be measured flowing through the portion of the measurement channel 11 in the sensor channel S.

On the other hand, the sensor substrate 21 outputs the measured flow rate as an electric signal. Therefore, the sensor substrate 2
1, as shown in FIG. 10, on the front surface side (mounting surface side to the body 41) of the printed circuit board 22 serving as the base,
A groove 23 is processed in the central portion. Then, on both sides of the groove 23, the electric circuit electrodes 24, 25, 26, 27 are formed.
Is provided. On the other hand, on the back surface side of the printed board 22, an electric circuit including electric elements 31, 32, 33, 34 and the like is provided (see FIG. 1). Then, in the printed circuit board 22, the electric circuit electrodes 24 to 27 are connected to the electric circuit constituted by the electric elements 31 to 34 and the like. Further, the measurement chip 11 is mounted on the front surface side of the printed board 22 as described later.

Here, the measuring chip 11 is shown in FIG.
Will be explained. 11A is a plan view of the measuring chip, and FIG. 11B is a side view of the measuring chip. As shown in FIG. 11, the measurement chip 11 is obtained by performing a semiconductor micromachining processing technique on a silicon chip 12, and at this time, the groove 13 is processed and the heating wire electrodes 14, 15, 16, 17 are provided on both sides of the groove 13. Further, at this time, the temperature sensor hot wire 18 is extended from the hot wire electrodes 14 and 15 and bridged over the groove 13, and the flow velocity sensor hot wire 19 is extended from the hot wire electrodes 16 and 17. And is installed on the groove 13. Furthermore, in the measurement chip 11, the flow rate sensor heating wire 1 is provided on the downstream side of the sensor flow path S.
9 is provided, and the run-up section L of the fluid to be measured F2 flowing through the sensor flow path S is provided long. This is because the flow of the fluid to be measured F2 flowing through the sensor channel S is adjusted.

Then, the heating wire electrode 1 of the measuring chip 11 is used.
4, 15, 16, 17 are joined to the electric circuit electrodes 24, 25, 26, 27 (see FIG. 10) of the sensor substrate 21 by solder reflow, a conductive adhesive, or the like. Are mounted on the sensor substrate 21. Therefore, when the measurement chip 11 is mounted on the sensor substrate 21, the temperature sensor hot wire 18 and the flow velocity sensor hot wire 19 provided on the measurement chip 11 are the hot wire electrodes 14 to 17 of the measurement chip 11 and the sensor substrate 21. Sensor circuit board 2 through the electric circuit electrodes 24 to 27 (see FIG. 10) of
1 will be connected to the electric circuit provided on the back side.

When the measuring chip 11 is mounted on the sensor substrate 21, the groove 13 of the measuring chip 11 overlaps the groove 23 of the sensor substrate 21A. Therefore, as shown in FIG. 1, when the sensor substrate 21 on which the measurement chip 11 is mounted is brought into close contact with the body 41 via the seal packing 48, the sensor substrate 21 and the measurement chip 11 are separated from each other in the channel space 44 of the body 41. An elongated sensor flow path S including the groove 13 of the measurement chip 11 and the groove 23 of the sensor substrate 21 is formed therebetween. Therefore, the temperature sensor heating wire 18 and the flow velocity sensor heating wire 19 are provided in the sensor flow path S so as to cross the bridge.

Next, the operation of the thermal type flow meter 1 having the above structure will be described. In the thermal type flow meter 1,
As shown in FIG. 1, the inlet channel 4 is connected through the inlet port 42.
The fluid to be measured (F in FIG. 1) that has flowed into the channel 3 is in the channel space 4
At 4, the flow is divided into a flow into the main flow path M (F1 in FIG. 1) and a flow into the sensor flow path S (F2 in FIG. 1). Then, the fluids to be measured flowing out from the main flow passage M and the sensor flow passage S join together and flow out from the outlet port 46 to the outside of the body 41 via the outlet flow passage 45 (F in FIG. 1).

Here, the fluid to be measured (F2 in FIG. 1) flowing into the sensor channel S flows into the sensor channel S after passing through the three-layer mesh portion 51M in the laminated filter 50. Further, the fluid to be measured flowing out from the main channel M and the sensor channel S is blocked by the shielding wall 47.
Merge at a point away from. Therefore, the vortex of the flow generated at the confluence does not affect the flow of the fluid to be measured (F2 in FIG. 1) flowing in the sensor channel S. Therefore,
The fluid to be measured in a state in which the flow is extremely adjusted flows through the sensor channel S.

The fluid to be measured (F2 in FIG. 1) flowing through the sensor flow path S draws heat from the temperature sensor heating wire 18 and the flow velocity sensor heating wire 19 bridged in the sensor flow path S.
Then, the electric circuit provided on the back surface side of the sensor substrate 21 causes the temperature sensor heating wire 18 and the flow velocity sensor heating wire 19 to move.
While detecting outputs such as, the temperature sensor hot wire 18 and the flow velocity sensor hot wire 19 are controlled to have a constant temperature difference.

An example of the output at this time is shown in FIGS. The graph of FIG. 12 shows the output (bridge output) from the thermal type flow meter 1. The graph in FIG. 13 is
The output (amplifier output) after passing the output from the thermal type flow meter 1 through an electric filter (low-pass filter) is shown. 12 and 13 show the output when the flow rate of the fluid to be measured (F in FIG. 1) flowing into the inlet port 42 of the thermal type flow meter 1 is 10 (l / min). The solid line shows the output of the thermal type flow meter 1 according to the first embodiment, and the broken line shows the output of the thermal type flow meter before improvement.

As is clear from FIGS. 12 and 13, the first
It can be seen that the thermal flow meter 1 according to the embodiment of the present invention has a smaller output vibration width than the unimproved thermal flow meter (Japanese Patent Application No. 2000-368801; the same applies hereinafter). Here, if the ratio of this vibration width to the output value is defined as noise,
In FIG. 12, the noise in the thermal flow meter before improvement is “22.36 (% FS)”, whereas the noise in the thermal flow meter 1 according to the first embodiment is “2.77.
(% FS) ". Further, in FIG. 13, the noise in the thermal type flow meter before improvement is “4.96 (% FS)”, whereas the noise in the thermal type flow meter 1 according to the first embodiment is “0. 43 (% FS) ". That is, according to the thermal type flow meter 1 according to the first embodiment, noise can be reduced to about 1/10. This is because the flow of the fluid to be measured flowing through the sensor flow path S is very regular as described above. Regarding the bridge span, the thermal flow meter 1 according to the first embodiment is “0.415 (V)”, and the thermal flow meter before improvement is “0.405 (V)”.

As described above, the thermal flow meter 1 has a very stable measurement output. The response is also about 50 msec, which is extremely high sensitivity. Therefore, when the thermal type flow meter 1 is used for confirming the suction of vacuum suction during handling during semiconductor chip mounting, the suction status can be accurately determined. This is because the flow rate in the orifice during adsorption and non-adsorption can be instantaneously and accurately and stably measured. Therefore, by using the thermal type flow meter 1 for confirmation of adsorption, it is possible to accurately perform adsorption confirmation without being erroneously determined as not adsorbing although it is actually adsorbed. As a result, the size of semiconductor chips (for example, 0.5 m
The handling work at the time of mounting (m square) can be performed very efficiently.

As described in detail above, according to the thermal type flow meter 1 according to the first embodiment, the laminated filter 50 is mounted in the flow passage space 44 formed in the body 41. The laminated filter 50 is provided with a three-layer mesh portion 51M arranged between the main flow passage M and the sensor flow passage S. Therefore, the fluid to be measured flows into the sensor channel S after passing through the three-layered mesh portion 51M. As a result, the flow of the fluid under measurement flowing into the sensor channel S is adjusted. That is, assuming that the flow of the fluid to be measured flowing into the main flow passage M is disturbed, the three-layer mesh portion 51M provided between the main flow passage M and the sensor flow passage S causes the sensor flow passage S
The flow of the fluid to be measured flowing into is regulated. Further, since three layers of the mesh portion 51M are provided, a larger rectifying effect can be obtained.

Further, the laminated filter 50 is provided with a shielding wall 47 formed by shielding portions 51C, 52C, 53C and 54C provided on the respective thin plates 51, 52, 53 and 54 constituting the laminated filter 50. . Therefore, the fluid to be measured flowing out from the sensor flow channel S and the fluid to be measured flowing out from the main flow channel M are formed in the body 41, and the outlet flow channel 4 is formed.
Merge at 5 (elbow part 45A). That is, the fluid to be measured flowing out from the sensor channel S and the fluid to be measured flowing out from the main channel M do not merge near the outlet of the sensor channel S. As a result, the confluence of the sensor channel S and the main channel M is kept away from the measurement chip 11. Therefore,
The flow vortices generated at the confluence of the sensor channel S and the main channel M do not disturb the flow of the fluid to be measured in the sensor channel S.

As described above, in the thermal type flow meter 1, since the laminated filter 50 is mounted in the flow passage space 44 formed in the body 41, even if the measured flow amount becomes large, the measured flow amount in the sensor flow passage S becomes large. The fluid flow is not disturbed. Therefore,
Even if the measurement flow rate is large, a stable measurement output can be obtained.

(Second Embodiment) Next, a second embodiment will be described. Therefore, FIG. 14 shows a schematic configuration of the thermal type flow meter according to the second embodiment. As shown in FIG. 14, the thermal type flow meter 201 according to the second embodiment is
The thermal flowmeter 1 according to the first embodiment has substantially the same structure as that of the thermal type flow meter 1 except that the laminated filter 5 is provided in the flow path space 44.
The difference is that a laminated filter 50A is mounted instead of 0. That is, the thermal type flow meter 20 according to the present embodiment
In FIG. 1, a laminated filter 50A having a smaller gap between the mesh portions 51M than that of the laminated filter 50 is mounted in the flow path space 44. Therefore, the points different from the first embodiment will be mainly described. In addition, about the thing of the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

Therefore, the laminated filter 50A will be described with reference to FIG. The laminated filter 50A is shown in FIG.
As shown in FIG. 11, a total of 11 sheets of four types of thin plates are laminated. That is, the mesh plate 51 and the first
Shielding plates 52, 52, 52, 52, second shielding plates 53, 5
3, mesh plates 51, 51, 51, and third shielding plate 5
4 is laminated and adhered. That is, the laminated filter 50A is obtained by changing the arrangement of the mesh plate 51 and the second shielding plate 53 in the laminated filter 50 (see FIG. 4). By changing this arrangement, the spacing between the mesh portions 51M is 0.2 mm.

Then, the thermal type flow meter 20 having the above structure
1 under the same conditions as in the first embodiment (flow rate: 10
(L / min)), the noise at the bridge output is "4.23 (% FS)" and the noise at the amplifier output is "0.69 (% F)".
S) ". The bridge span is "0.426.
(V) ”. The noise at the bridge output of the thermal flowmeter before improvement is “22.36 (% FS)”, and the noise at the amplifier output is “4.96 (% F)”.
S) ".

Therefore, according to the thermal type flow meter 201 according to the second embodiment, noise can be reduced to about 1/5. That is, the measurement output is stabilized. However, it can be seen that the noise is worse than the noise of the thermal type flow meter 1 according to the first embodiment. From this, it can be said that a greater effect can be obtained by arranging the mesh portions 51M at intervals of about 0.7 mm.

As described above in detail, according to the thermal type flow meter 201 of the second embodiment, the laminated filter 50A is mounted in the flow passage space 44 formed in the body 41. Then, in the laminated filter 50A, a three-layer mesh portion 51 arranged between the main flow passage M and the sensor flow passage S is provided.
It has M. Therefore, the fluid to be measured flows into the sensor channel S after passing through the three-layered mesh portion 51M. As a result, the flow of the fluid under measurement flowing into the sensor channel S is adjusted. That is, if the flow of the fluid to be measured flowing into the main flow channel M is disturbed, the fluid to be measured flowing into the sensor flow channel S is prevented by the three-layer mesh portion 51M provided between the main flow channel M and the sensor flow channel S. The flow is adjusted. Moreover, since three layers of the mesh portion 51M are provided,
A larger rectifying effect can be obtained.

Further, the laminated filter 50A is provided with a shielding wall 47 formed by shielding portions 51C, 52C, 53C and 54C provided on the respective thin plates 51, 52, 53 and 54 constituting the laminated filter 50. . Therefore, the fluid to be measured flowing out from the sensor channel S and the fluid to be measured flowing out from the main channel M join at the outlet channel 45 (elbow portion 45A) formed in the body 41. That is, the fluid to be measured flowing out from the sensor channel S and the fluid to be measured flowing out from the main channel M do not merge near the outlet of the sensor channel S. As a result, the confluence of the sensor channel S and the main channel M is kept away from the measurement chip 11. Therefore, the vortex of the flow generated at the confluence of the sensor channel S and the main channel M does not disturb the flow of the fluid to be measured in the sensor channel S.

As described above, the thermal type flow meter 201 has the body 4
Since the laminated filter 50A is mounted in the flow path space 44 formed in 1, even if the measured flow rate increases,
The flow of the fluid to be measured in the sensor channel S is not disturbed. Therefore, a stable measurement output can be obtained even when the measurement flow rate is large.

(Third Embodiment) Next, a third embodiment will be described. Therefore, FIG. 16 shows a schematic configuration of the thermal type flow meter according to the third embodiment. As shown in FIG. 16, the thermal type flow meter 301 according to the third embodiment is
The thermal flowmeter 1 according to the first embodiment has substantially the same structure as that of the thermal type flow meter 1 except that the laminated filter 5 is provided in the flow path space 44.
The difference is that a laminated filter 60 is mounted instead of 0. That is, the thermal type flow meter 301 according to the present embodiment
In the flow path space 4 is a laminated filter 60 having a plurality of grooves.
It is attached to 4. In addition, the laminated filter 60 includes the first
The mesh portion 5 is different from the laminated filter 50 of the embodiment.
It is also different in that it does not have 1M. Therefore, the first
The differences from the above embodiment will be mainly described. The first
The same configurations as those in the embodiment are given the same reference numerals and the description thereof will be omitted.

Therefore, the laminated filter 60 is shown in FIG.
This will be described using 7. As shown in FIG. 17, the laminated filter 60 is formed by laminating a total of 10 thin plates of three types. That is, in order from the bottom, the mesh plate 51 and the first groove filters 55, 55, 55, 55, 55, 55, 55, 5
5 and the third shielding plate 54 are laminated and adhered.

Now, the first groove filter 55 will be described with reference to FIG. 18A is a plan view of the first groove filter, FIG. 18B is a cross-sectional view taken along the line AA in FIG. 18A, and FIG. 18C is FIG.
It is a BB sectional view in (a). First groove filter 5
As shown in FIG. 18, reference numeral 5 denotes an outer peripheral portion 55B and a shielding portion 55.
C and the central portion 55D are left, and the groove 55 is formed in the central portion 55D.
It is etched so that E is formed. That is, the first groove filter 55 includes the second shielding plate 53.
A groove 55E is provided in the central portion 53D (see FIG. 8). Then, the central portion 55 of the first groove filter 55
In the D, four grooves 55E are formed, two on each side. The depth of this groove 55E is 0.35 mm,
The width of 5E is 0.9 mm. The interval between adjacent grooves is 1.05 mm. The thickness of the first groove filter 55 is 0.5 mm.

These mesh plate 51 and the first groove filter 5
By mounting the laminated filter 60 in which the fifth and third shielding plates 54 are laminated and adhered as shown in FIG. 17 in the flow path space 44 formed in the body 41, as shown in FIG. A large number of fine flow paths are formed in the main flow path M by the grooves 55E formed in the central portion 55D of the groove filter 55. As a result, the fluid to be measured flowing into the main flow path M flows in each groove 55E. Therefore, the flow of the fluid under measurement flowing through the main flow path M is adjusted. Further, in the first groove filter 55, by forming the grooves 55E on both sides, the laminated body filter 60 can be provided with more grooves 55E, and a greater rectifying effect can be obtained.

The laminated filter 60 includes the thin plates 5
Shields 51C, 54C, 5 provided at 1, 54, 55
There is a shielding wall 47A formed by 5. This shield plate 47A also has the same effect as the shield plate 47 included in the thermal type flow meter 1 according to the first embodiment. That is, the vortex of the flow generated at the confluence of the sensor channel S and the main channel M does not disturb the flow of the fluid to be measured in the sensor channel S.

Then, the thermal type flow meter 30 having the above structure
1 under the same conditions as in the first embodiment (flow rate: 10
(L / min)), the noise at the bridge output is "6.84 (% FS)" and the noise at the amplifier output is "1.42 (% F)".
S) ". The bridge span is "0.679.
(V) ”. The noise at the bridge output of the thermal flowmeter before improvement is “22.36 (% FS)”, and the noise at the amplifier output is “4.96 (% F)”.
S) ".

Therefore, according to the thermal type flow meter 301 according to the third embodiment, the noise can be reduced to about 1/3. That is, the measurement output is stabilized. However, it can be seen that the noise is worse than the noise of the thermal type flow meter 1 according to the first embodiment. Therefore, the mesh portion 51M is provided between the main flow passage M and the sensor flow passage S rather than providing the rectifying mechanism (the groove 55E) in the main flow passage M.
It can be said that the provision of is more effective.

As described above in detail, according to the thermal type flow meter 301 of the third embodiment, the laminated filter 60 is mounted in the flow passage space 44 formed in the body 41. The laminated filter 60 is provided with a groove 55E that divides the main channel M into a plurality of channels. For this reason,
The flow of the fluid to be measured flowing into the main channel M is adjusted. Thereby, the flow of the fluid to be measured in the main channel M does not adversely affect the flow of the fluid to be measured in the sensor channel S. That is, the flow of the fluid to be measured in the sensor channel S is always stable.

Further, the laminated filter 60 is provided with a shielding wall 47A formed by shielding portions 51C, 54C and 55C provided on the respective thin plates 51, 54 and 55 constituting the laminated filter 60. Therefore, the fluid to be measured flowing out from the sensor channel S and the fluid to be measured flowing out from the main channel M join at the outlet channel 45 (elbow portion 45A) formed in the body 41. That is, the fluid to be measured flowing out from the sensor channel S and the fluid to be measured flowing out from the main channel M are
There is no merging near the outlet of the sensor channel S. As a result, the confluence of the sensor channel S and the main channel M is kept away from the measurement chip 11. Therefore, the sensor channel S
The vortex of the flow generated at the confluence of the main flow path M and the main flow path M does not disturb the flow of the fluid under measurement in the sensor flow path S.

As described above, the thermal type flow meter 301 has the body 4
Since the laminated filter 60 is mounted in the flow passage space 44 formed in 1, the plurality of grooves 55E (rectifying mechanism) that divides the main flow passage M into a plurality of flow passages are arranged. The flow of the fluid to be measured flowing is adjusted. further,
A shielding plate 47A is arranged at the confluence point of the sensor channel S and the main channel M so as to keep the flow vortex generated at the confluence point from disturbing the flow of the fluid to be measured in the sensor channel S. It Therefore, the flow of the fluid to be measured in the main channel M is not disturbed, and the sensor channel S and the main channel M are not disturbed.
The vortex of the flow generated at the confluence point with does not disturb the flow of the fluid to be measured in the sensor channel S. Therefore, even if the measured flow rate is large, the flow of the fluid to be measured in the sensor flow path S is not disturbed. Therefore, a stable measurement output can be obtained even when the measurement flow rate is large.

(Fourth Embodiment) Finally, a fourth embodiment will be described. Therefore, FIG. 19 shows a schematic configuration of the thermal type flow meter according to the fourth embodiment. As shown in FIG. 19, a thermal type flow meter 401 according to the fourth embodiment
Has almost the same configuration as the thermal type flow meter 1 according to the first embodiment, except that the laminated filter 70 is mounted in the flow path space 44 instead of the laminated filter 50. That is, the thermal type flow meter 4 according to the present embodiment
In No. 01, as in the third embodiment, the laminated filter 70 having a plurality of grooves is mounted in the flow path space 44. However, the laminated filter 70 is different from the laminated filter 60 of the third embodiment in that the shielding wall 47A is not provided.
And the number of grooves is different. Therefore, the first
The differences from the (and third) embodiment will be mainly described. In addition, about the thing of the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

Therefore, the laminated filter 70 is shown in FIG.
It will be described using 0. As shown in FIG. 20, the laminated filter 70 is formed by laminating a total of 10 thin plates of two types. That is, in order from the bottom, the mesh plate 51 and the second groove filters 56, 56, 56, 56, 56, 56, 56, 5
6, 56 are laminated and adhered.

Now, the second groove filter 56 will be described with reference to FIG. 21 (a) is a plan view of the second groove filter, FIG. 21 (b) is a sectional view taken along line AA in FIG. 21 (a), and FIG. 21 (c) is FIG.
It is a BB sectional view in (a). Second groove filter 5
As shown in FIG. 21, 6 is an outer peripheral portion 56B and a central portion 56.
Etching is performed so that the groove 56E is formed in the central portion 56D while leaving D and D. That is, the second groove filter 56 includes the central portion 53D (see FIG. 8) of the second shielding plate 53.
While the groove 56 </ b> E is provided in the reference portion), the shielding portion 53 </ b> C is not provided. Further, three grooves 56E are formed on one surface of the central portion 56D. The groove 56E has a depth of 0.35 mm and the groove 55E has a width of 1.1 mm. The interval between adjacent grooves is 0.2 mm. The thickness of the second groove filter 56 is 0.5 mm.
Is.

The mesh plate 51 and the second groove filter 5
As shown in FIG. 19, the second groove filter 56 is mounted by mounting the laminated filter 70 in which 5 is laminated and adhered as shown in FIG. 20 in the flow path space 44 formed in the body 41.
Of the main channel M by the groove 56E formed in the central portion 56D of the
A large number of fine flow paths are formed in. As a result, the fluid to be measured flowing into the main flow path M flows in each groove 56E.
Therefore, the flow of the fluid under measurement flowing through the main flow path M is adjusted. Further, the second groove filter 56 has three grooves 56E.
Since the groove is formed, the laminated filter 70 can be provided with more grooves 56E, and a greater rectifying effect can be obtained.

The thermal type flow meter 40 having the above structure
1 under the same conditions as in the first embodiment (flow rate: 10
(L / min)), the noise at the bridge output is "13.47 (% FS)" and the noise at the amplifier output is "1.76 (% F)".
S) ". The bridge span is "0.498".
(V) ”. The noise at the bridge output of the thermal flowmeter before improvement is “22.36 (% FS)”, and the noise at the amplifier output is “4.96 (% F)”.
S) ".

Therefore, according to the thermal type flow meter 401 according to the fourth embodiment, noise can be reduced to about 3/5. That is, the measurement output is stabilized. However, it can be seen that the noise is worse than the noise of the thermal type flow meter 1 according to the third embodiment. From this, it can be said that a greater effect can be obtained by providing the shielding wall 47A.

Further, instead of mounting the laminated filter 70 in the flow passage space 44 of the body 41, a columnar pin 80 having a plurality of fins 81 as shown in FIG. 22 may be arranged in the main flow passage M. Good. Such a pin 80 is connected to the main flow path M
This is because a plurality of flow channels are formed in the main flow channel M and the flow of the fluid to be measured flowing through the main flow channel M is also adjusted by providing the above.

Then, the output under the same conditions (flow rate: 10 (l / min)) as in the first embodiment was confirmed by the thermal type flow meter when the pin 80 is arranged in the main flow path M. , The noise at the bridge output is "1
6.22 (% FS) ", and the noise in the amplifier output was" 3.26 (% FS) ". The bridge span is “0.469 (V)”. Then, the noise in the bridge output of the thermal type flow meter before improvement is "22.
36 (% FS) "and the noise in the amplifier output is" 4.96 (% FS) ". Therefore, the noise can be reduced to about 3/4 simply by disposing the pin 80 in the main flow path M. That is, the measurement output is stabilized. However, the stabilizing effect is not so great.

As described above in detail, according to the thermal type flow meter 401 of the fourth embodiment, the laminated filter 70 is mounted in the flow passage space 44 formed in the body 41. The laminated filter 70 is provided with a groove 56E that divides the main channel M into a plurality of channels. For this reason,
The flow of the fluid to be measured flowing into the main channel M is adjusted. Thereby, the flow of the fluid to be measured in the main channel M does not adversely affect the flow of the fluid to be measured in the sensor channel S. That is, even if the measured flow rate increases, the sensor flow path S
The flow of the measured fluid at is stable. Therefore, a stable measurement output can be obtained even when the measurement flow rate is large.

The above-described embodiment is merely an example, does not limit the present invention, and it is needless to say that various improvements and modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, four types of laminated filters are illustrated, but the present invention is not limited thereto, and the thin plates 51 to 56 can be arbitrarily combined to form a laminated filter.

[0085]

As described above, according to the thermal type flow meter of the present invention, since the filter is provided between the bypass channel and the sensor channel, the measured flow rate becomes large and the fluid in the bypass channel is increased. Even if the flow of the fluid is disturbed, the flow of the fluid flowing into the sensor channel is adjusted. Further, since the rectifying mechanism that regulates the flow of the fluid by forming a plurality of channels in the bypass channel is provided, the flow of the fluid in the bypass channel can be regulated even if the measured flow rate becomes large. Furthermore, since there is a shielding wall that joins the fluid flowing out from the sensor channel and the fluid flowing out from the bypass channel in the outlet channel formed in the body, the confluence point of the sensor channel and the bypass channel is set. Can be kept away from heat rays. As a result, the flow of the fluid in the sensor channel is stable even if the measured flow rate increases. Therefore, even if the measured flow rate becomes large, the measured output can be stably obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a thermal type flow meter according to a first embodiment.

FIG. 2 is a plan view of a body.

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

FIG. 4 is an exploded perspective view of a laminated filter.

FIG. 5 is a diagram showing a mesh plate, (a) is a plan view,
(B) is AA sectional drawing.

6 is an enlarged view of the mesh portion of FIG.

FIG. 7 is a diagram showing a first shielding plate, (a) is a plan view,
(B) is AA sectional drawing.

FIG. 8 is a view showing a second shielding plate, (a) is a plan view,
(B) is AA sectional drawing.

FIG. 9 is a view showing a third shielding plate, (a) is a plan view,
(B) is AA sectional drawing.

FIG. 10 is a perspective view of a sensor substrate.

11A and 11B are diagrams showing a measurement chip, FIG. 11A is a plan view, and FIG. 11B is a side view.

FIG. 12 is a diagram showing an example of an output (bridge output) of the thermal type flow meter.

FIG. 13 is a diagram similarly showing an example of the output (amplifier output) of the thermal type flow meter.

FIG. 14 is a schematic configuration diagram of a thermal type flow meter according to a second embodiment.

FIG. 15 is an exploded perspective view of a laminated filter.

FIG. 16 is a schematic configuration diagram of a thermal type flow meter according to a third embodiment.

FIG. 17 is an exploded perspective view of a laminated filter.

FIG. 18 is a diagram showing a first groove filter, (a) is a plan view, (b) is a sectional view taken along line AA, and (c) is B.
It is a -B sectional view.

FIG. 19 is a schematic configuration diagram of a thermal type flow meter according to a fourth embodiment.

FIG. 20 is an exploded perspective view of a laminated filter.

FIG. 21 is a view showing a second groove filter, (a) is a plan view, (b) is a sectional view taken along line AA, and (c) is B.
It is a -B sectional view.

FIG. 22 is a front view of a rectifying pin in a thermal type flow meter according to a fifth embodiment.

FIG. 23 is a cross-sectional view of a conventional thermal type flow meter.

FIG. 24 is a perspective view of a measuring element used in a conventional heat flow meter.

[Explanation of symbols]

1 Thermal flow meter 41 body 44 flow path space 47 Shielding wall 50 laminated filter 51 mesh plate 51M mesh part 52 First shield plate 53 Second shielding plate 54 Third Shielding Plate 55 First groove filter 55E groove 52C, 53C, 54C, 55C Shield 56 Second groove filter 56E groove M Main flow path (bypass flow path) S sensor flow path

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeru Hayashimoto             250 Ojiki 2-chome, Komaki City, Aichi Prefecture             Inside the company (72) Inventor Akiichi Kitagawa             250 Ojiki 2-chome, Komaki City, Aichi Prefecture             Inside the company F term (reference) 2F035 EA03 EA04 EA08

Claims (13)

[Claims] 1. A thermal type flow meter comprising a bypass flow path for the sensor flow path, in addition to a sensor flow path in which a heating wire for measuring a flow rate is installed, wherein the bypass flow path and the sensor flow path are connected to each other. A thermal type flow meter characterized by having a filter provided therebetween. 2. The thermal type flow meter according to claim 1, wherein the filter is formed by laminating a plurality of meshes. 3. The thermal type flow meter according to claim 2, wherein the meshes are laminated via a spacer having a predetermined thickness. 4. A thermal type flow meter comprising a bypass flow passage for the sensor flow passage in addition to a sensor flow passage in which a heating wire for measuring a flow amount is installed, wherein a plurality of flow passages are provided in the bypass flow passage. A thermal type flow meter having a rectifying mechanism for regulating the flow of fluid by forming the flow meter. 5. The thermal type flow meter according to claim 4, wherein the rectifying mechanism is a stack of thin plates having grooves formed therein. 6. The thermal type flow meter according to claim 5, wherein the thin plate has a plurality of grooves formed therein. 7. The thermal type flowmeter according to claim 4, wherein the rectifying mechanism is a pin having a plurality of fins formed therein. 8. A thermal type flow meter comprising a sensor flow channel in which a heating wire for measuring a flow rate is installed, and a bypass flow channel for the sensor flow channel, wherein the fluid flowing out from the sensor flow channel and the bypass flow channel. A thermal type flow meter having a shielding wall that joins a fluid flowing out from a flow channel at an outlet flow channel formed in a body. 9. The thermal type flow meter according to claim 8, wherein the outlet channel is not formed on the same straight line with respect to the bypass channel. 10. The thermal type flowmeter according to claim 8 or 9, wherein the shielding wall is formed by laminating a plurality of shielding plates. . 11. The method according to any one of claims 1 to 10.
In the thermal type flow meter described in item 1, the bypass flow path includes a substrate provided with a side surface opening on a substrate on which an electrode for an electric circuit for connecting to an electric circuit for performing a measurement principle using a heat ray is provided. A body in which a flow path is formed is formed by closely contacting the side opening so as to close the side surface opening, and the sensor flow path is a measurement chip provided with a heat wire and a heat wire electrode connected to the heat wire. A thermal flow rate characterized by being formed by a groove provided in at least one of the measurement chip or the substrate by bonding the heat wire electrode and the electric circuit electrode to each other and mounting them on the substrate. Total. 12. A substrate having an electric circuit electrode for connecting to an electric circuit for performing a measurement principle using a heat wire on a surface of a substrate, wherein A bypass flow path formed by closely contacting the side opening with the body formed with an outlet flow path that is not on the line, and a heat wire and a heat wire electrode connected to the heat wire are provided. A measurement chip, a sensor channel formed by a groove provided in at least one of the measurement chip or the substrate by mounting the heat wire electrode and the electric circuit electrode on the substrate by bonding. And a filter in which a plurality of meshes are laminated between the bypass flow channel and the sensor flow channel, a fluid flowing out from the sensor flow channel, and a flow out from the bypass flow channel. And a shielding wall that allows the fluid that flows into the outlet channel to join together. 13. The thermal type flow meter according to claim 12, wherein the shield wall is composed of a plurality of shield plates, and the filter and the shield wall are provided in one laminated body. Characteristic thermal type flow meter.