JP2006078487A - Guide path - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guide path that eliminates pulsation in a sensor output even in a high flow rate region, while guiding a gas of an object to be measured to a sensor in a condition that waste materials such as dust and dirt are properly removed. <P>SOLUTION: The guide path comprises narrow paths 31-35 for raising the flow speed of a gas and deposition chambers 21-25 forming hollow rectangular solids for depositing the waste materials in the gas. The outlets of the narrow paths 31-35 are opened by pulling either side of right and left sides of one side wall surface of the deposition chambers 21-25, and the gas outlets from the deposition chambers 21-25 are opened to side wall surfaces of far sides from the outlets of the narrow paths 31-35 from among side wall surfaces vertical to one side wall surface to which the outlets of the narrow paths 31-35 are opened, and therewith the opening position is set at a position sufficiently separated from a side wall surface facing one side wall surface forward than it. Thereby, the gas changes a flow direction thereof at an angle larger than 90 degrees from flowing in to flowing out and passes widely in the deposition chambers 21-25, and then a deposition place is spread and the deposition chambers 21-25 are efficiently utilized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a guide path for guiding a gas to a sensor in a state suitable for measurement, such as removing unnecessary substances such as dust, dust, mist-like moisture, and oil from a measurement target gas.

  In recent years, in a combustion apparatus such as a water heater, in order to supply an appropriate amount of air, the flow velocity of air sent from the combustion fan is measured with a hot wire flow velocity sensor or the like, and the rotational speed of the combustion fan is controlled based on this. ing.

  In this way, a hot-wire flow rate sensor, which is one of the sensors that measure the flow rate of gas, has two temperature detecting thin film resistance elements in the vicinity of the resistance element that acts as a heater, and the gas to be measured. The gas flow velocity is detected on the basis of the temperature difference detected by the two thin film resistance elements for temperature detection.

  With such a sensor, accurate measurement cannot be performed if dust adheres to the surface of the sensor. Therefore, in addition to minute dust such as dust and dust from the gas to be measured, unnecessary substances such as mist-like moisture and oil Measures are taken to remove

  For example, as shown in FIG. 14, a gas inlet 1402 is provided on one side wall surface 1401 of a deposition chamber 1400 having a certain capacity so as to be shifted to one corner, and is provided at a corner opposite to the facing side wall surface 1403. A gas outlet 1404 is provided, and a gas guiding path for dust traps configured to increase the flow velocity from a narrow flow path to the previous inlet 1402 and to send the gas is disposed in front of the sensor.

  In such a gas guide path, the unnecessary matter contained in the gas flowing into the deposition chamber 1400 at a high flow rate has a mass larger than that of the gas molecules. It collides with the facing side wall surface 1403 and deposits. On the other hand, the gas having a small inertia flows through the deposition chamber 1400 obliquely from the inlet 1402 toward the outlet 1404.

  In such a conventional gas guide path, since the gas inlet and outlet are provided near the opposite corners of the side wall surface facing each other, unnecessary substances in the gas are only present at the front portion of the inlet as shown by the oblique lines in FIG. accumulate. For this reason, there is a problem that the entrance of the deposition chamber is likely to be clogged and unnecessary materials are deposited only in a part of the deposition chamber, so that the deposition chamber is not effectively used. Moreover, it was difficult to completely remove unnecessary materials only in the deposition chamber.

  In addition, when a hot-wire flow rate sensor is used in a high flow rate region, there is a problem that gas cannot vibrate or pulsate due to bending or the like in the flow path and a stable sensor output cannot be obtained.

  The present invention has been made paying attention to such problems of the conventional technology, and guides the gas to be measured to the sensor in a state in which unnecessary objects such as dust and dust are appropriately removed, An object of the present invention is to provide a gas guiding path in which no pulsation occurs in the sensor output even in the flow velocity region.

The gist of the present invention for achieving the object lies in the inventions of the following items.
[1] In a gas guiding path for guiding a gas to be measured to a predetermined sensor (70),
An acceleration channel (102, 202) for increasing the flow velocity of the gas to be measured, and an inlet is opened on a side wall surface of the acceleration channel (102, 202), and the acceleration channel (102, 202) and a bypass flow path (110, 210) for diverting a part of the gas accelerated in step 202)
A gas guiding path characterized in that the sensor (70) is arranged in the middle of the bypass flow path (110, 210).

[2] In a gas guiding path for guiding a gas to be measured to a predetermined sensor (70),
An accelerating flow path portion (102, 202) for increasing the flow velocity of the gas to be measured, and a bypass flow path (301 to 303) in which an inlet portion is opened on a side wall surface of the previous flow path, Provided a plurality of stages in which a part of the gas in the passage is shunted with the opening part opened on the side wall surface of the acceleration channel part (102, 202) as the first stage,
A gas guiding path characterized in that the sensor (70) is arranged in the middle of the final stage bypass flow path (303).

[3] The flow path cross-sectional area of at least the place where the sensor (70) is arranged in the bypass flow path (110, 210) is made smaller than other portions of the bypass flow path (110, 210). The gas guiding path according to [1] or [2], which is characterized.

[4] In the gas guiding path for guiding the gas to be measured to the predetermined sensor (70),
A gas guiding path, characterized in that a chamber (401) as a pressure equalizing chamber is provided upstream of the sensor (70).

[5] The gas guiding path according to [4], wherein the volume of the chamber (401) as the pressure equalizing chamber is set according to the maximum flow velocity of the gas reaching the sensor (70).

The present invention operates as follows.
An acceleration channel (102, 202) for increasing the flow velocity of the gas to be measured, an inlet is opened in the side wall surface of the acceleration channel (102, 202), and the acceleration channel (102, 202). In the gas guide path having a bypass flow path (110, 210) for diverting a part of the gas accelerated in step), unnecessary mass having a large mass is accelerated by the acceleration flow path section (102, 202). Since the flow rate is increased, the inertial action appears strongly, passes in front of the inlet of the bypass channel (110, 210), and unnecessary materials are removed to the bypass channel (110, 210). Only gas components flow in. Therefore, by disposing the sensor (70) in the middle of the bypass flow path, it is possible to avoid unnecessary objects from reaching the sensor (70).

  Further, a plurality of bypass channels (110, 210) are provided so that a part of the gas is diverted from the bypass channel (110, 210) in the previous stage, and a sensor ( 70), it is possible to more effectively prevent unwanted objects from reaching the sensor (70). In addition, since unnecessary objects are not deposited, it is possible to avoid a change in pressure loss due to accumulation of unnecessary objects.

  In addition, since the flow rate of the gas in the bypass flow path (110, 210) becomes smaller than the flow rate of the original gas by the diversion, at least the sensor (70) is disposed in the bypass flow path (110, 210). The flow path cross-sectional area of the place to be made is made smaller than the other part of the bypass flow path (110, 210). As a result, the flow rate (flow velocity) of the gas passing immediately in front of the sensor (70) increases, and the sensitivity is prevented from decreasing.

  In addition, a chamber (401) as a pressure equalizing chamber is provided on the upstream side of the sensor (70). Further, the volume of the chamber (401) as the pressure equalizing chamber is set according to the maximum flow velocity of the gas reaching the sensor (70). By providing the chamber (401) having a certain volume on the upstream side of the sensor (70) in this way, even when the gas flow rate is increased, pulsation appears in the output of the hot wire flow rate sensor (70). Can be prevented. In addition, since the capacity | capacitance of the chamber (401) required in order to prevent a pulsation increases, so that the flow velocity increases, the capacity | capacitance of the chamber (401) is set according to the maximum flow velocity estimated.

  Accelerate the gas guiding path that leads the gas to the sensor with an acceleration channel that increases the gas flow velocity and a bypass channel that divides a part of the gas accelerated in the acceleration channel. As a result, the inertia of an unnecessary object having a large mass is increased, the unnecessary object passes in front of the inlet portion of the bypass channel, and only the gas component from which the unnecessary object is removed flows into the bypass channel. Therefore, by disposing the sensor in the middle of the bypass flow path, it is possible to effectively avoid unnecessary objects from reaching the sensor.

  Furthermore, in the gas guide path provided with a chamber as a pressure equalizing chamber upstream of the sensor, it is possible to prevent pulsation from appearing in a high flow velocity region in the sensor output of a hot wire flow velocity sensor or the like.

Hereinafter, various embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a gas guiding path 10 according to a first embodiment of the present invention. Each figure shows the gas guiding path main body 10a with the top cover and bottom cover removed. FIG. 1 is a view of the gas guiding path body 10a as viewed from above, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a view of the gas guiding path body 10a as viewed from below. 4 shows the BB cross section of FIG.

  The gas guiding path 10 serves to remove dust and dust contained in the gas, or unnecessary substances such as mist-like moisture and oil before being sent to a sensor such as the hot-wire flow rate sensor 70.

  The hot wire type flow rate sensor 70 has two temperature detecting thin film resistance elements arranged in the vicinity of the resistance element acting as a heater, divided into the upstream side and the downstream side of the gas flow to be measured. The gas flow velocity is detected based on the temperature difference detected by the two thin film resistance elements for temperature detection.

  The hot-wire flow rate sensor 70 is used in a combustion apparatus such as a water heater for the purpose of measuring the flow rate of air actually sent from a combustion fan in order to ensure an appropriate air ratio.

  The gas guide path 10 includes a gas guide path main body 10a shown in the drawings, and an upper cover and a bottom cover that are not shown. The gas guiding path main body 10a connects the gas inlet 11, the gas outlet 12, the plurality of deposition chambers 21 to 25 for removing unnecessary substances, and the adjacent deposition chambers, and increases the gas flow rate. The narrow passage portions 31 to 35, the front chamber 40, the narrow passage portion 36 connecting the deposition chamber 25 and the front chamber 40 in the final stage, the sensor attachment passage portion 50, and the rear chamber 60. Note that the cross-sectional area of the narrow passage portions 31 to 36 is sufficiently smaller than that of the deposition chambers 21 to 25.

  The gas flowing in from the gas inlet 11 is from the first narrow passage portion 31 to the first deposition chamber 21 to the second narrow passage portion 32 to the second deposition chamber 22 to the third narrow passage portion 33 to third. The pre-chamber 40 sequentially passes through the deposition chamber 23 to the fourth narrow passage portion 34 to the fourth deposition chamber 24 to the fifth narrow passage portion 35 to the fifth deposition chamber 25 to the sixth narrow passage portion 36. To come to reach.

  In the front chamber 40, an inlet 51 to the sensor mounting passage 50 is opened. The gas in the front chamber 40 escapes from the inlet 51 to the back side of the gas guiding path 10, passes through the constricted sensor mounting passage 50 in the center as shown in FIGS. 3 and 4, and passes from the outlet 52 to the rear chamber 60. The gas flows out and is discharged from the gas guiding path 10 through the gas outlet 12. The sensor mounting passage 50 itself is in the form of a groove, and the flow path is formed by covering the sensor mounting passage 50 from the back side with a flat plate 71 on which a hot-wire flow velocity sensor 70 is mounted as shown in FIG. It is supposed to be formed.

  As shown in FIG. 2, each of the deposition chambers 21 to 25 is formed deeper than the cross-sectional height of the narrow passage portions 31 to 36, and each of the narrow passage portions 31 to 36 is located at a position near the upper lid (not shown). 21 to 25 and the front chamber 40 are connected. The narrow passage portions 31 to 36 and the deposition chambers 21 to 25 are formed as passages and chambers, respectively, by closing the upper lid.

  In the first deposition chamber 21, the fourth deposition chamber 24, and the fifth deposition chamber 25, the gas inlet opens at a position that is shifted to one of the left and right corners of one side wall surface, The outlet is a side wall surface that is farthest from the inlet side of the two side wall surfaces that are perpendicular to the side wall surface that the inlet opens, and is opened at a position that is farthest from the opposite side wall surface of the inlet. Yes.

  In the second deposition chamber 22, the inlet is opened in the same manner as described above, and the gas outlet is at the center upper portion of the side wall surface far from the inlet of the two side wall surfaces perpendicular to the side wall surface where the inlet is opened. Is open. Since the inlet of the third deposition chamber 23 communicates with the outlet of the second deposition chamber 22, it also opens at the center upper portion of the side wall surface. The gas outlet of the third deposition chamber 23 is one of the side wall surfaces perpendicular to the side wall surface where the inlet is open, and is opened at a position near the corner farthest from the side wall surface facing the inlet. ing. Here, each of the deposition chambers 21 to 25 has a hollow rectangular parallelepiped shape with a side of 6 mm and a depth of 8 mm, and each of the narrow passage portions 31 to 36 has a cross section of about 2 mm square.

Next, the operation will be described.
FIG. 5 shows a state in which the first narrow passage portion 31, the first deposition chamber 21, and the second narrow passage portion 32 are viewed from above. The gas flowing in from the first narrow passage portion 31 flows into the first deposition chamber 21 in a state where the flow velocity is increased because the flow passage cross-sectional area of the first narrow passage portion 31 is small. Dust and dust, or unnecessary substances such as mist-like moisture and oil have a mass density larger than that of the gas itself, so go straight in the direction of flowing from the first narrow passage portion 31 due to inertia, It collides with the opposite side wall surface 81 and falls downward and accumulates. On the other hand, the gas having a small inertia changes its direction in the deposition chamber and flows from the second narrow passage portion 32 to the next deposition chamber.

  Here, since the gas outlet 32 from the deposition chamber has a positional relationship as shown in the figure with respect to the inlet 31, the gas changes direction by 90 degrees or more in the deposition chamber and passes through the deposition chamber over a wide range. The place where unnecessary materials can be deposited is wider than that of the conventional one shown in FIG. 14, and the deposition chamber can be effectively used as a place for depositing unnecessary materials.

  It is to be noted that the gas outlet is located at the center upper portion of the side wall surface as in the second deposition chamber 22, or the gas inlet is located at the center upper portion of the side wall surface as in the third deposition chamber 23. However, as compared with the case where the exit exists on the surface facing the entrance, it is possible to secure a large number of deposits of unnecessary materials.

  Furthermore, since the unnecessary matter colliding with the side wall surface is deposited sequentially from the bottom of the deposition chamber, the depth of the deposition chambers 21 to 25 is made larger than the cross-sectional height of the narrow passage portions 31 to 36, and the narrow passage portions 31 to 35. By providing the outlet and the gas outlet from the deposition chambers 21 to 25 near the upper surface of the deposition chamber, it is possible to accumulate more unnecessary materials in the deposition chamber until the inlet and the outlet are clogged.

  In addition, the removal effect of an unnecessary thing is heightened by connecting the some deposition chambers 21-25 in series via the narrow channel | path parts 31-36. In addition, by including the one having the gas inlet / outlet at the center of the side wall surface like the third deposition chamber 23, a large number of deposition chambers can be densely arranged, which contributes to the miniaturization of the gas guiding path 10.

  1 and the like, since the deposition chambers 21 to 25 are provided only on the upstream side of the hot-wire flow rate sensor 70, compared to the case where deposition chambers are provided on both the upstream side and the downstream side of the sensor. This is suitable when the pressure loss is reduced and gas needs to flow through the sensor at a high speed (when using a sensor for low pressure loss).

  FIG. 6 shows a gas guiding path 100 according to the second embodiment of the present invention. The gas guiding path 100 includes a gas introduction port 101, an acceleration channel portion 102 that increases the flow velocity of the gas that has flowed in, a bypass channel 110, and a gas outlet port 104. The inlet of the bypass channel 110 opens in the side wall of the acceleration channel unit 102, and the outlet opens in the side wall of the gas outlet port 104.

  The flow passage cross-sectional area of the acceleration flow passage portion 102 is smaller than the gas inlet 101 in order to increase the flow velocity, and the flow passage cross-sectional area of the bypass flow passage 110 is further smaller than that of the acceleration flow passage portion 102. ing. A hot-wire flow rate sensor 70 is disposed in the middle of the bypass flow path 110.

Next, the operation will be described.
The flow rate of the gas flowing in from the gas introduction port 101 is increased by entering the acceleration channel portion 102 having a small channel cross-sectional area. In addition, since the outlet of the bypass channel 110 opens to the gas outlet port 104 having a lower pressure than that in the acceleration channel unit 102, a part of the gas having a high flow velocity in the acceleration channel unit 102 is The flow is diverted to the bypass flow path 110 side, and the rest goes straight and reaches the gas outlet 104.

  Dust and dust contained in the gas flowing in from the gas inlet 101, or unnecessary substances such as mist-like moisture and oil enter the flow path portion 102 for acceleration to increase the flow velocity and increase the inertia. For this reason, the unnecessary substance 121 in the gas passes straight through the front face of the inlet of the bypass channel 110 and hardly enters the bypass channel 110. Therefore, the gas from which unnecessary substances are removed reaches the hot-wire flow rate sensor 70.

  As described above, in the gas guiding path 100, it is possible to prevent an unnecessary object from reaching the hot-wire flow rate sensor 70 without depositing an unnecessary object. As a result, problems such as clogging of the deposition chamber due to the accumulation of unnecessary materials and an increase in pressure loss due to the accumulation of a large amount of unnecessary materials and an error in the measurement result of the flow velocity do not occur.

  FIG. 7 shows a gas guiding path 200 according to the third embodiment of the present invention. The gas guiding path 200 includes a gas introduction port 201, an acceleration channel portion 202 that increases the flow velocity of the gas that has flowed in, a bypass channel 210, and a gas outlet port 204. The acceleration flow path section 202 has a throttle section 203 with a flow path cross-sectional area reduced in the middle thereof.

  The inlet of the bypass channel 210 opens to the side wall of the acceleration channel unit 202 on the upstream side of the throttle unit 203, and the outlet of the bypass channel 210 is located immediately downstream of the throttle unit 203 on the acceleration channel unit 202. Open to the side wall. The flow path cross-sectional area of the acceleration flow path section 202 is smaller than the gas inlet 201 in order to increase the flow velocity, and the flow path cross-sectional area of the bypass flow path 210 is further smaller than that of the acceleration flow path section 202. It has become. A hot-wire flow rate sensor 70 is arranged in the middle of the bypass flow path 210.

Next, the operation will be described.
The gas flowing in from the gas inlet 201 has an increased flow velocity when entering the acceleration channel portion 202 having a small channel cross-sectional area. Further, since the outlet of the acceleration channel portion 202 is open to a low pressure region immediately downstream of the throttle portion 203 provided in the middle of the acceleration channel portion 202, the acceleration channel from the outlet of the bypass channel 210 is opened. Gas is sucked out to the part 202. As a result, part of the gas that has flowed into the acceleration channel portion 202 from the gas inlet 201 is diverted to the bypass channel 210 side.

  Unnecessary substances in the gas whose flow velocity has been increased by flowing into the acceleration flow path section 202 from the gas inlet 201 pass straight through the front face of the bypass flow path 210 due to its inertia, and almost pass. The same effect as shown in FIG. 6 can be obtained without entering the bypass flow path 210.

  By dividing the gas, the flow rate of the gas in the bypass channels 110 and 210 becomes smaller than the original flow rate of the gas flowing into the gas inlets 101 and 201. Therefore, as shown in FIG. 8, in the bypass flow paths 110 and 210, the vicinity of the hot-wire flow rate sensor 70 is passed in front of the hot-wire flow rate sensor 70 by making the flow path cross-sectional area smaller than other portions. The flow rate of the gas to be increased can be compensated for. That is, the flow rate (velocity) of the gas that actually passes in front of the sensor is reduced by making the vicinity of the sensor in the bypass flow path narrower than other parts and bringing the flow path width close to the size of the contact surface of the sensor. Can be increased, and a decrease in sensitivity can be compensated.

  Further, as shown in FIG. 9, the bypass flow path excluding the final stage is provided with a function as an acceleration flow path, a plurality of bypass flow paths 301 to 303 are connected, and the final-stage bypass flow path 303 is connected to a hot-wire type. A flow rate sensor 70 may be provided. As a result, the amount of unwanted matter reaching the hot wire flow rate sensor 70 can be further reduced. In addition, when the gas flow velocity is sufficiently increased in the acceleration flow channel portion following the gas introduction port, it is not necessary to provide a function of accelerating the gas flow velocity in each bypass flow channel. However, in order to divert the gas to the bypass flow path side, for example, it is necessary to provide the throttle portion shown in FIG. 7 in the bypass flow path other than the final stage.

  Next, the gas induction path 400 concerning the 4th Embodiment of this invention is demonstrated. FIG. 10 shows a gas guiding path 400 in which measures are taken so that the output value of the hot-wire flow rate sensor 70 does not pulsate even when used in a high flow rate region.

  The gas guiding path 400 includes a chamber 401 that functions as a pressure equalizing chamber on the upstream side of the hot-wire flow rate sensor 70. FIG. 11 shows the relationship between the gas flow velocity and the output of the hot wire flow velocity sensor 70 when the chamber 401 is not provided. In this figure, the vertical axis indicates the sensor output, the horizontal axis indicates the time, and the state in which the flow rate is increased stepwise for each predetermined time. In this example, since the flow velocity exceeds 4 m / s, the output value of the hot-wire flow velocity sensor 70 is not stable and pulsation 501 appears. This indicates that the flow velocity of the gas passing in front of the sensor fluctuates so as to actually pulsate since the flow velocity of flow exceeds 4 m / s.

  FIG. 12 shows the same measurement results as FIG. 11 when the chamber 401 is provided on the upstream side of the hot-wire flow rate sensor 70. As described above, by arranging the chamber 401, pulsation around a flow velocity of 4 m / s is suppressed, and pulsation is observed for the first time around a flow velocity of 7 m / s.

  FIG. 13 shows the relationship between the volume of the chamber 401, the gas flow rate, and the sensor output. A portion indicated by a dotted line is a flow velocity region where pulsation occurs.

  From this figure, it can be seen that as the flow rate increases, the volume of the chamber required to suppress the pulsation increases. Therefore, by setting the capacity of the chamber 401 according to the maximum flow velocity of the gas flowing in front of the sensor, it is possible to accurately prevent pulsation from occurring in a necessary flow velocity region. In addition, the front chamber 40 of what was shown in 1st Embodiment has fulfill | performed the function as the chamber of this Embodiment.

  In the embodiment described above, the hot-wire flow rate sensor is used as the sensor provided in the gas guiding path. However, other types of sensors may be used as long as they are required to remove unnecessary materials. Further, in the gas guiding path according to the first embodiment, the narrow passage portion has a short length equal to the wall thickness of the deposition chamber, but a longer duct may be used as the narrow passage portion. In this case, the direction of travel of the unwanted material that has flowed into the deposition chamber from the entrance becomes stronger, and even if the direction of gas flow in the deposition chamber is greatly changed, the unwanted material is allowed to collide with the wall facing the entrance accurately. Can be made.

The best mode for carrying out the invention includes the inventions of the following items.
[1] In a gas guiding path for removing unnecessary substances in the gas,
Narrow passage portions (31 to 35) for increasing the flow velocity of the gas, and deposition chambers (21 to 25) having hollow cuboids for depositing unnecessary substances in the gas, the passage sectional area of which is With a narrow passage (31-35) larger than,
The outlet of the narrow passage portion (31-35) is opened on one side wall surface of the deposition chamber (21-25),
The one side wall surface in which the outlet of the narrow passage portion (31 to 35) is opened in the outlet portion of the gas from the deposition chamber (21 to 25) among the side wall surfaces of the deposition chamber (21 to 25). A gas guide path provided at a position separated from the side wall surface facing the one side wall surface among the side wall surfaces perpendicular to the first side wall surface.

[2] In a gas guiding path for removing unnecessary substances in the gas,
Narrow passage portions (31 to 35) for increasing the flow velocity of the gas, and deposition chambers (21 to 25) having hollow cuboids for depositing unnecessary substances in the gas, the passage sectional area of which is With a narrow passage (31-35) larger than,
The outlet of the narrow passage portion (31 to 35) is opened to one of the left and right sides of one side wall surface of the deposition chamber (21 to 25),
The one side wall surface in which the outlet of the narrow passage portion (31 to 35) is opened in the outlet portion of the gas from the deposition chamber (21 to 25) among the side wall surfaces of the deposition chamber (21 to 25). A gas guiding path provided at a position separated from a side wall surface facing the one side wall surface in a side wall surface perpendicular to the narrow channel portion (31 to 35) and far from the outlet of the narrow channel portion (31 to 35) .

[3] The gas outlet from the deposition chamber (21-25) is provided near the one side wall surface where the outlet of the narrow passage (31-35) is open [1] ] Or the gas guiding path according to [2].

[4] The height of the deposition chamber (21-25) is made larger than the cross-sectional height of the narrow passage portion (31-35), and the outlet of the narrow passage portion (31-35) and the deposition chamber (21-21). 25) The gas guiding path according to [1], [2] or [3], wherein an outlet portion of the gas from 25) is provided near the top surface of the deposition chamber (21 to 25).

[5] [1], [2], [3] or [4], wherein a plurality of deposition chambers (21 to 25) are connected in series via the narrow passage portions (31 to 35) Gas guideway.

[6] The deposition chambers (21 to 25) and the narrow passage portions (31 to 35) are arranged only on the upstream side in the gas flow of a predetermined sensor whose measurement target is the gas. 1], [2], [3], [4] or [5].

The present invention operates as follows.
The gas outlet from the deposition chamber (21-25) faces the first side wall in the side wall perpendicular to the side wall where the outlet of the narrow passage (31-35) opens. Since the gas flowing into the deposition chambers (21-25) from the narrow passage portions (31-35) exits the deposition chambers (21-25), the direction of the flow is Is passed through the deposition chamber (21-25) over a wide range by changing the angle 90 degrees or more. Therefore, the place where an unnecessary thing accumulates spreads, and the deposition chamber (21-25) can be used effectively as a deposit place of an unwanted object.

  Moreover, the exit of the narrow channel | path part (31-35) is opened in one side of the side wall surface of the deposition chamber (21-25), and the gas exit part from the deposition chamber (21-25) is made open. It is provided on the side wall surface far from the opening of the outlet of the narrow passage portion (31 to 35), or the outlet portion of the gas from the deposition chamber (21 to 25) is opened at the outlet of the narrow passage portion (31 to 35). In the case where it is provided close to the one side wall surface side, the gas passes through the deposition chamber (21-25) more extensively after entering the deposition chamber (21-25) and exiting, It is possible to further expand the depositing place for unnecessary materials.

  Further, the height of the deposition chamber (21-25) is made larger than the cross-sectional height of the narrow passage portion (31-35), and the gas from the outlet of the narrow passage portion (31-35) and the deposition chamber (21-25) In the case where the outlet portion is provided near the top surface of the deposition chamber (21 to 25), unnecessary matter colliding with the side wall surface due to inertia is deposited in order from the bottom of the deposition chamber (21 to 25). More unnecessary materials can be accumulated in the deposition chambers (21 to 25) until the inlet and outlet are clogged.

  In addition, in the thing which connects a some deposition chamber (21-25) in series via a narrow channel | path part (31-35), the removal effect of an unnecessary thing can be improved further. Further, in the configuration in which the deposition chambers (21 to 25) and the narrow passage portions (31 to 35) are arranged only on the upstream side of the predetermined sensor (70) for measuring gas, the upstream of the sensor (70). Compared with the case where the deposition chambers (21 to 25) are provided on both the downstream side and the downstream side, the pressure loss is reduced, and when the gas needs to flow at a high speed before the sensor (70), that is, a sensor for low pressure loss is provided. It is suitable for use.

  According to the gas guide path of the present invention, the gas accelerated in the narrow passage portion changes in the flow direction by 90 degrees or more from flowing into the deposition chamber and exiting the deposition chamber so as to pass through the deposition chamber over a wide range. Since the arrangement of the inlet and the outlet is determined, the place where the unnecessary material is deposited spreads, and the deposition chamber can be effectively used as a place for depositing the unnecessary material. Thereby, clogging of the deposition chamber hardly occurs and a long life can be obtained.

It is a top view which shows the gas induction path main-body part which concerns on the 1st Embodiment of this invention. It is sectional drawing in the location where a deposition chamber exists among the gas induction path main-body parts which concern on the 1st Embodiment of this invention. It is a bottom view which shows the gas induction path main-body part which concerns on the 1st Embodiment of this invention. It is sectional drawing in the center position of the gas induction path main-body part which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the locus | trajectory of the gas in the gas induction path which concerns on the 1st Embodiment of this invention, and the deposit place of an unnecessary material. It is sectional drawing which shows the gas induction path which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the gas induction path which concerns on the 3rd Embodiment of this invention. It is explanatory drawing which shows an example which further narrowed the flow-path cross-sectional area around the sensor. It is explanatory drawing which shows an example of what made the bypass flow path the multistage structure. It is sectional drawing which shows the gas induction path which concerns on the 4th Embodiment of this invention. It is explanatory drawing which shows an example of the relationship between the sensor output and the flow velocity when there is no chamber. It is explanatory drawing which shows an example of the relationship between the sensor output in the case of providing a chamber, and the flow velocity. It is explanatory drawing which shows the relationship between a flow velocity, a sensor output, and the volume of a chamber. It is explanatory drawing which shows the locus | trajectory of the gas in the gas guide path used conventionally, and the deposit location of an unnecessary material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Gas induction path 10a ... Gas induction path main-body part 11 ... Gas inflow port 12 ... Gas outflow port 21-25 ... Deposition chamber 31-36 ... Narrow channel | path part 40 ... Front chamber 50 ... Sensor attachment channel | path part 51 ... Inlet 52 ... Outlet 60 ... Rear chamber 70 ... Heat flow rate sensor 71 ... Plate 100, 200 ... Gas induction path 101, 201 ... Gas inlet 102, 202 ... Acceleration channel 104,204 ... Gas outlet 110,210 ... Bypass flow Path 203 ... Restriction section 400 ... Gas induction path 401 ... Chamber

Claims (5)

In a gas guiding path for guiding a gas to be measured to a predetermined sensor,
An accelerating flow path portion that increases the flow velocity of the gas to be measured, and a bypass flow that opens an inlet portion on the side wall surface of the accelerating flow path portion and diverts part of the gas accelerated in the accelerating flow path portion With roads,
A gas guide path configured to arrange the sensor in the middle of the bypass flow path. In a gas guiding path for guiding a gas to be measured to a predetermined sensor,
An acceleration flow path portion that increases the flow velocity of the gas to be measured, and a bypass flow path having an inlet portion opened on the side wall surface of the previous flow path, and part of the gas in the previous flow path is diverted Provided a plurality of stages as the first stage with the opening part on the side wall surface of the acceleration flow path part,
A gas induction path configured to arrange the sensor in the middle of a final-stage bypass flow path.   3. The gas guiding path according to claim 1, wherein at least a portion of the bypass channel where the sensor is disposed has a smaller channel cross-sectional area than other portions of the bypass channel. In a gas guiding path for guiding a gas to be measured to a predetermined sensor,
A gas guiding path characterized in that a chamber as a pressure equalizing chamber is provided upstream of the sensor.   The gas guiding path according to claim 4, wherein the volume of the pressure equalizing chamber is set in accordance with a maximum flow velocity of the gas reaching the sensor.

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