TWI636239B - Barometer - Google Patents

Abstract

An object of the present invention is to provide an ultrasonic gas flow meter capable of reducing the number of parts or assembly man-hours.

The filter 15 in the present invention includes a cylindrical member 16 having an outer peripheral shape corresponding to the inner wall surface of the inlet flow path portion 12a, and an end wall 17 connected to one end of the cylindrical member 16 and provided with a gas. The opening of the passage 17a. The filter 15 is housed and held by the inner wall surface of the inlet flow path portion 12a.

Description

Barometer

The invention relates to a gas flow meter.

There have been known a variety of gas flow meters for measuring the flow rate of a gas, such as an ultrasonic gas flow meter. The ultrasonic gas flowmeter is equipped with a pair of acoustic transducers (ultrasonic flow velocity sensors) composed of a piezoelectric vibrator operating at an ultrasonic frequency, etc., and a pair of ultrasonic flow velocity sensors are fixed. The distance interval is arranged in the gas flow path.

The main body of the gas flow meter is provided with a gas inflow port connected to a gas supply source and a gas outflow port connected to a burner or the like. A gas flow path is formed inside the main body from the gas inflow port to the gas outflow port. The gas flow path is composed of an inlet flow path portion that communicates with a gas inlet and flows gas in an up-and-down direction, an outlet flow path portion that communicates with a gas outlet and flows in a vertical direction, and an inlet flow path portion and an outlet flow. The intermediate flow path portion is connected to the road portion, and has a substantially U-shaped curved flow path shape.

A cylindrical flow path sleeve provided with a rectifying plate for rectifying gas flow is arranged in the middle flow path portion, and flows from the inlet flow path portion to the outlet flow path. The internal gas system flows in the flow path sleeve. A pair of ultrasonic flow velocity sensors is arranged on the side of the flow path sleeve, and measures the flow velocity of the gas flowing in the flow path sleeve through the pair of ultrasonic flow velocity sensors.

However, since the inlet flow path portion is provided with a blocking valve or the like for blocking the flow of the gas, it has a complicated flow path structure in which the gas temporarily flows to the back side of the gas flow meter or passes through a portion where the flow path is locally reduced. Due to the complicated flow path structure, the gas flowing through the inlet flow path part is disordered, and the gas in the disordered state flows into the flow path sleeve. For this reason, the flow measurement may be deviated, and the flow error may increase. Big.

Therefore, for example, Patent Document 1 discloses a structure in which a rectifying plate that rectifies the flow of a gas is disposed near an inlet of a measuring tube (flow path sleeve). The fairing plate is mounted on the flow path member from the bottom surface side of the main body. Further, for example, Patent Document 2 discloses a structure in which a rectifying plate is disposed on a wall portion formed on an inlet flow path portion. A boss having a screw hole is provided on the upper wall portion so as to protrude in the gas flow direction. In addition, the rectifying plate includes a screw hole penetrating through the plate thickness direction, and is fixed to the hub by a screw.

[Prior technical literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2009-186429.

Patent Document 2: Japanese Patent Laid-Open No. 2010-008116.

However, according to the methods disclosed in Patent Documents 1 and 2, it is necessary to assemble and fix a flat plate-shaped rectifier plate to a gas flow path, which leads to problems such as an increase in the number of parts or an increase in assembly man-hours. In addition, the assembly work in a narrow gas flow path results in poor workability, resulting in an increase in assembly man-hours.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic gas flow meter capable of reducing the number of parts or assembly man-hours.

In order to solve the above problems, the gas flow meter of the present invention includes: a main body, which has a series of gas flow paths formed from a gas inlet to a gas outlet, and the bottom surface is open; a bottom cover is provided on the bottom surface of the main body , Covering the bottom side of the main body to close the gas flow path; a measurement unit configured in the gas flow path and configured by assembling a sensor in a cylindrical flow path sleeve; and a filter configured in the measurement Near the unit, the flow of the gas flowing through the gas flow path is rectified; the filter has: a cylindrical member having an outer peripheral shape corresponding to the inner wall surface of the gas flow path; and an end wall having an end portion on either side of the cylindrical member Connected and provided with an opening that becomes a gas passage; the filter is housed and held by the inner wall surface of the gas flow path.

Here, in the present invention, it is preferable that the gas flow route communicates with the gas flow inlet. The inlet flow path part, the outlet flow path part that communicates with the gas flow outlet, and the intermediate flow path part that communicates with the inlet flow path part and the outlet flow path part, respectively, and accommodates the measurement unit, are provided with a substantially U-shaped curved flow. The filter is arranged in one or both of the inlet channel portion and the outlet channel portion.

Further, in the present invention, it is preferable that the filter is embedded in the flow path portion such that the end wall is located at the upper end of the tube member, and the lower end of the filter is held by a receiving portion formed in the bottom cover.

According to the present invention, since the cylindrical filter is inserted into the gas flow path and the filter is accommodated and held in the gas flow path, the filter can be easily assembled. In this case, there is no need for other members for assembly or fixing, so the number of parts or assembly man-hours can be reduced. Moreover, it is not necessary to perform complicated operations such as nut tightening in a narrow flow path, so workability is improved, and assembly man-hours can be reduced.

10‧‧‧ flow meter body

10a‧‧‧Main body

10a1‧‧‧Groove section

10b‧‧‧Front cover

11a‧‧‧Gas inlet

11b‧‧‧Gas Outlet

12‧‧‧Gas flow path

12a‧‧‧Inlet flow section

12a1‧‧‧ opening

12b‧‧‧Middle Flow Section

12c‧‧‧Exit flow section

15‧‧‧ Filter

16‧‧‧ tube member

16a‧‧‧ opening

16b‧‧‧ protrusion

16b1‧‧‧ rib

16c‧‧‧bottom

17‧‧‧ end wall

17a‧‧‧Gas passage

17a1‧‧‧ opening 1

17a2‧‧‧ opening 2

17b‧‧‧Wheel

20‧‧‧ bottom cover

21‧‧‧ recess

21a‧‧‧ entrance recess

21a1‧‧‧ week side wall

21a2‧‧‧Support Department

21b‧‧‧Middle recess

21c‧‧‧Outlet recess

30‧‧‧ measurement unit

31‧‧‧flow sleeve

32‧‧‧ Ultrasonic flow velocity sensor

33‧‧‧Control Board

36‧‧‧O-ring holding section

FIG. 1 is a front view showing the configuration of an ultrasonic gas flow meter according to this embodiment.

FIG. 2 is a cross-sectional view schematically showing the internal structure of the ultrasonic gas flow meter according to this embodiment.

FIG. 3 is a perspective view schematically showing a main part of the bottom cover.

Fig. 4 is a perspective view showing the structure of a filter.

Fig. 5 is an explanatory view schematically showing a state after the filter is assembled.

Fig. 6 is an explanatory view schematically showing a state before the filter is assembled.

FIG. 1 is a front view showing the configuration of an ultrasonic gas flow meter according to this embodiment. FIG. 2 is a cross-sectional view schematically showing the internal structure of the ultrasonic gas flow meter according to this embodiment. The ultrasonic gas flow meter of this embodiment is a gas flow meter that measures a gas flow rate of an ultrasonic flow velocity sensor by transmitting and receiving one of the ultrasonic waves. The ultrasonic gas flowmeter is mainly composed of a flowmeter body 10, a bottom cover 20, and a measurement unit 30.

The flowmeter main body 10 includes a main body 10a formed of a metal material such as aluminum or an aluminum alloy, and a resin front cover 10b provided on the front surface of the main body 10a, and is stored and controlled in a gap between the main body 10a and the front cover 10b. Substrate, etc.

An upper portion of the main body 10a includes a gas inflow port 11a to which a pipe from a gas supply source is connected, and a gas outflow port 11b to which a burner or the like is connected. Further, a series of gas flow paths 12 are provided inside the main body 10a from one of the gas flow inlet 11a to the gas flow outlet 11b.

The gas flow path 12 is composed of an inlet flow path part 12a, an intermediate flow path part 12b, and an outlet flow path part 12c, and has a substantially U-shaped curved flow path shape. shape. The flow path sections 12a to 12c are arranged from the gas flow inlet 11a to the gas flow outlet 11b in this order from the inlet flow path section 12a, the intermediate flow path section 12b, and the outlet flow path section 12c.

The inlet flow path portion 12a communicates with the gas inlet 11a and is formed in the vertical direction. A circular opening portion 12a1 is set in the middle portion of the inlet flow path portion 12a. When the gas flowing in from the gas inlet 11a flows downward, the gas flows from the front side (front side) of the flow meter body 10 to the rear side (rear side) at the opening portion 12a1, and then changes direction to flow downward again. A blocking valve (not shown) is provided in the opening portion 12a1. The valve body of the blocking valve protrudes from the front to the back to block the opening portion 12a1, thereby blocking the flow of gas in the middle of the inlet flow path portion 12a.

The outlet flow path portion 12c communicates with the gas flow outlet 11b, and is formed in the same vertical direction as the inlet flow path portion 12a.

The intermediate flow path portion 12b communicates with the inlet flow path portion 12a and the outlet flow path portion 12c, respectively, and is formed in the left-right direction. A measurement unit 30 is housed and arranged in the intermediate flow path portion 12b.

The bottom surface of the main body 10a has an open structure, and a gas flow path 12 formed inside the main body 10a is exposed on the open bottom surface side. The bottom cover 20 is disposed on the bottom surface of the flow meter body 10 and covers the bottom surface side of the body body 10a to close the gas flow path 12. The bottom cover 20 is connected to the main body 10a Similarly, it is formed of a metal material such as aluminum or an aluminum alloy.

FIG. 3 is a perspective view schematically showing a main part of the bottom cover 20. A recess 21 is formed on the upper surface of the bottom cover 20, that is, the surface facing the inside of the flowmeter body 10 in the longitudinal direction. The recessed portion 21 includes an inlet recessed portion 21a corresponding to the inlet flow path portion 12a, an intermediate recessed portion 21b corresponding to the intermediate flow path portion 12b, and an outlet recessed portion 21c corresponding to the outlet flow path portion 12c.

The entrance recess 21a and the exit recess 21c are formed wider than the middle recess 21b and the distance (depth) from the bottom is larger. The peripheral shapes of the inlet concave portion 21a and the outlet concave portion 21c on the upper surface side of the bottom cover 20 are set so as to correspond to the peripheral shapes of the inlet flow channel portion 12a and the outlet flow channel portion 12c on the bottom surface side of the main body 10a. On the other hand, the middle recess 21b is set such that its width corresponds to the outer width of the flow path sleeve 31 of the measurement unit 30, and its depth is about one and a half of the height of the flow path sleeve 31.

Supporting portions 21a2 are formed on the peripheral side wall 21a1 of the inlet recessed portion 21a. In this embodiment, the supporting portions 21a2 are set at two locations corresponding to the front side and the back side of the flowmeter body 10, respectively. The receiving portion 21a2 is formed by bulging toward the inside of the entrance recess 21a, and is continuously formed along the height direction (up and down direction) of the peripheral side wall 21a1.

The measurement unit 30 is mainly composed of a flow path sleeve 31, a pair of ultrasonic flow velocity sensors 32, and a control substrate 33. Regarding the flow path sleeve 31, which is below One half of the side is inserted into and fixed to the middle recessed portion 21 b of the bottom cover 20, and is disposed on the middle flow path portion 12 b such that the axial direction of the flow path sleeve 31 is horizontal. In this configuration, a pair of ultrasonic flow velocity sensors 32 are assembled on the upper side of the flow path sleeve 31.

The flow path sleeve 31 is a long cylindrical member that is set longer than the distance between the central axis of the gas inflow port 11a and the central axis of the gas outflow port 11b, and one of the opening ends faces the inlet flow path. The part 12a and the other open end part are arrange | positioned so that it may face the exit flow path part 12c. The gas flowing through the inlet flow path portion 12a flows into the flow path sleeve 31 from one open end portion, and after flowing through the flow path sleeve 31, flows out from the other open end portion to the outlet flow path portion 12c. A plurality of rectifying plates (not shown) for rectifying the flow of gas are laminated in the flow path sleeve 31.

The flow path sleeve 31 is provided with two O-ring retaining portions 36 provided at a desired interval in the longitudinal direction. The two O-ring retaining portions 36 are portions where O-rings such as rubber can be provided, and When the flow path sleeve 31 is arranged in the middle recessed portion 21b, it is located at both ends of the middle recessed portion 21b, respectively. Therefore, the O-ring held in the O-ring holding portion 36 is in close contact with the middle recessed portion 21b, and the close contact portion functions as a sealing portion. Thereby, the airtightness is ensured so that the gas in the inlet concave portion 21a of the bottom cover 20 does not flow into the outlet concave portion 21c through the gap between the flow path sleeve 31 and the intermediate concave portion 21b. In addition, the O-ring is also in close contact with the flowmeter body 10 side, so that there is no gap between the flow path sleeve 31 and the flowmeter body 10.

A pair of ultrasonic flow velocity sensors 32 is a system in which the ultrasonic signals sent from one of the ultrasonic flow velocity sensors 32 are reflected by the bottom surface of the flow path sleeve 31 and are transmitted by the other ultrasonic flow velocity sensor. 32 receiving reflective unit.

The control substrate 33 performs transmission processing of ultrasonic signals, measurement of propagation time, and the like. A protection sleeve (not shown) for protecting the control substrate 33 is assembled on the upper surface of the flow path sleeve 31.

The filter 15 which is one of the features of this embodiment will be described below. Here, FIG. 4 is a perspective view showing the configuration of the filter 15. FIG. 5 is an explanatory diagram schematically showing a state after the filter 15 is assembled, and FIG. 6 is an explanatory diagram schematically showing a state before the filter 15 is assembled. The filter 15 is disposed in the inlet flow path portion 12 a and rectifies the flow of the gas flowing into the measurement unit 30, that is, the flow of the gas flowing through the inlet flow path portion 12 a. This filter 15 is arranged in the vicinity of the measurement unit 30, particularly in a region further downstream than the opening portion 12a1 of the inlet flow path portion 12a.

The filter 15 is mainly composed of a cylindrical member 16 and an end wall 17 extending in the vertical direction.

The cylindrical member 16 is formed in a substantially rectangular cylindrical shape, and its outer peripheral shape has a shape corresponding to the inner wall surface of the inlet flow path portion 12a. Lower end 16c of tube member 16 Stay open. Further, an opening 16 a necessary for arranging the flow path sleeve 31 is provided in a part of the cylindrical member 16.

The end wall 17 is connected to the upper end of the cylindrical member 16 and is configured to be a substantially vertical surface with respect to the flow of the gas in the inlet flow path portion 12a. A gas passage 17a is formed in a part of the end wall 17 with an opening set to a desired shape. The gas passage 17a has a function of rectifying the flow of the gas on the downstream side from the end wall 17 by passing the gas flowing through the inlet flow path portion 12a. The gas passage 17a is set to a desired shape determined by the rectifying function. In this embodiment, a substantially rectangular first opening 17a1 formed in a central portion of the end wall 17 and an adjacent first opening 17a1 are provided. The substantially rectangular second opening 17a2 is formed in a wide width in the front-rear direction.

In the filter 15, a protruding portion 16 b protruding outward is formed on a peripheral edge portion on the lower end 16 c side of the cylindrical member 16. The protrusions 16b are set on both sides of the opening 16a, respectively. A rib 16b1 having a predetermined height is formed on the upper surface of each protrusion 16b. A margin in the height direction (up-down direction) is given to the protruding portion 16b by the rib portion 16b1.

On the other hand, a groove portion 10a1 corresponding to the two protruding portions 16b is set at a desired position of the peripheral edge portion of the inlet flow path portion 12a on the bottom surface side of the main body 10a. When the filter 15 is assembled in the inlet flow path portion 12a, the protruding portion 16b and the groove portion 10a1 are fitted to each other (see FIG. 5). package The height of the protruding portion 16b including the rib portion 16b1 is set to be slightly larger than the depth of the groove portion 10a1.

Further, a hub portion 17b composed of a cylindrical protrusion is erected on the end wall 17 of the filter 15. On the other hand, an upper wall surface is formed at a desired position of the inlet flow path portion 12a of the main body 10a, and a convex portion (not shown) corresponding to the hub portion 17b is set on the upper wall surface. When the filter 15 is assembled in the inlet flow path portion 12a, the hub portion 17b and the convex portion are fitted to each other (see FIG. 2).

The filter 15 is assembled to the inlet flow path portion 12a by inserting the filter 15 into the inlet flow path portion 12a from the bottom surface side of the main body 10a. As shown in FIG. 6, the filter 15 has the end wall 17 first fitted into the inlet flow path portion 12 a.

At this time, the hub portion 17b set on the end wall 17 is fitted into the convex portion of the inlet flow path portion 12a, whereby the filter 15 is positioned. Similarly, a pair of protrusions 16b provided in the cylindrical member 16 are fitted into a pair of groove portions 10a1 provided in the inlet flow path portion 12a provided on the bottom surface side of the main body 10a.

At this time, by setting the rib portion 16b1 of the protruding portion 16b, the lower end (the lower end 16c of the cylindrical member 16) of the filter 15 embedded in the inlet flow path portion 12a is slightly protruded from the peripheral edge portion of the inlet flow path portion 12a. status.

When the bottom cover 20 is attached to the main body 10a, the bottom surface side of the main body 10a is covered with the bottom cover 20, and the gas flow path 12 is closed. The bottom cover 20 is crimped and fixed to the main body 10a by means such as nut fastening.

Due to the installation of the bottom cover 20, the bottom surface of the main body 10a is subjected to the pressing force of the bottom cover 20. Thereby, a pair of protrusions 16b set in the cylindrical member 16 are pressed into the groove portion 10a1 of the inlet flow path portion 12a. Further, one pair of the receiving portions 21a2 of the inlet recessed portion 21a is set to press the lower end of the filter 15 (the lower end 16c of the cylindrical member 16), whereby the filter 15 is pushed into the inside of the inlet flow path portion 12a, The lower end of the bottom cover 20 is held to the receiving portion 21a2.

In this state, the filter 15 is embedded in the inlet flow path portion 12a and is housed and held by the inner wall surface of the inlet flow path portion 12a.

By assembling the filter 15, a gas passage 17 a is arranged in the middle of the flow of the gas in the inlet flow path portion 12 a. The gas flows through the gas passage 17 a, thereby rectifying the flow of the gas on the downstream side of the end wall 17, that is, the flow of the gas flowing into the measurement unit 30. As a result, it is possible to suppress the uneven flow of the gas flowing into the measurement unit 30, and thus it is possible to suppress the occurrence of erroneous measurement of the flow rate or the inability to measure.

In addition, since the outer peripheral shape of the filter 15 (tube member 16) is set to a shape corresponding to the inner wall surface of the inlet flow path portion 12a, it is possible to eliminate the occurrence therebetween. The gap. As a result, the gas flowing through the inlet flow path portion 12a does not flow into the gap between the filter 15 and the inlet flow path portion 12a, and flows through the gas passage 17a. As a result, the rectifying effect of the filter 15 can be appropriately obtained.

As described above, according to the present embodiment, the filter 15 includes a cylindrical member 16 having an outer peripheral shape corresponding to the inner wall surface of the inlet flow path portion 12a, and an end wall 17 connected to one end of the cylindrical member 16 and An opening serving as a gas passage 17a is provided. The filter 15 is housed and held by the inner wall surface of the inlet flow path portion 12a.

According to this configuration, the end wall 17 provided with the rectifying gas passage 17 a is configured integrally with the cylindrical member 16. In addition, since the bottom surface side of the flow meter body 10 is open, the filter 15 is housed and held in the inlet flow path portion 12a by fitting the cylindrical filter 15 to the inlet flow path portion 12a. Therefore, the filter 15 can be easily assembled into the inlet flow path portion 12a. Therefore, there is no need for additional components for assembly or fixing, which can reduce the number of parts or assembly man-hours. In addition, since complicated operations such as nut tightening are not required, workability is improved, and assembly man-hours can be reduced.

Further, in the present embodiment, the filter 15 is fitted into the inlet flow path portion 12 a so that the end wall 17 is positioned above the cylindrical member 16. At this time, the lower end of the filter 15 (the lower end 16c of the cylindrical member 16) is held by a receiving portion 21a2 formed in the bottom cover 20.

According to this configuration, the filter 15 is held by the receiving portion 21a2, This can prevent the filter 15 from falling into the inside of the bottom cover 20 (the inlet recess 21 a). In addition, the lower end of the filter 15 (the lower end 16c of the cylindrical member 16) is held by the receiving portions 21a2 at the two locations on the front side and the back side, so that the position of the filter 15 in the up and down direction can be properly maintained.

Further, in this embodiment, as a positioning means for positioning the filter 15 of the inlet flow path portion 12a, a cylindrical hub portion 17b erected on the end wall 17 and an inlet flow path portion 12a disposed on the main body 10a are provided. Inside convex part. This positioning means positions the filter 15 in the direction of the surface of the end wall 17 and the direction perpendicular to the surface by fitting the hub portion 17b and the convex portion to each other.

With this configuration, the position and height of the filter 15 can be appropriately determined. In addition, positioning can be performed only by fitting the hub portion 17b and the convex portion to each other, thereby improving workability.

Furthermore, in this embodiment, as a fixing means for fixing the filter 15 of the inlet flow path portion 12a, there is a protruding portion 16b protruding outward from the peripheral edge portion of the lower end 16c of the cylindrical member 16 and set to face the main body 10a The groove portion 10a1 at the peripheral edge portion of the inlet flow path portion 12a on the bottom surface side. This fixing means fixes the filter 15 by fitting the protruding portion 16b and the groove portion 10a1 to each other.

According to this configuration, the protruding portion 16b and the groove portion 10a1 are fitted to each other. When the filter 15 is closed, the filter 15 can be prevented from shaking.

Further, in the present embodiment, a rib 16b1 is provided in the protruding portion 16b, and a margin in the height direction of the protruding portion 16b is ensured by the rib 16b1. The protruding portion 16b is set so as to protrude more than the groove portion 10a1 by a height corresponding to the rib portion 16b1, and the protruding portion 16b is pressed into the groove portion 10a1 by mounting the bottom cover 20. Thereby, the filter 15 is firmly fixed, and it is possible to effectively suppress the occurrence of shaking.

Furthermore, in this embodiment, the filter 15 is arranged only at the inlet flow path portion 12a, but the filter 15 may be arranged only at the outlet flow path portion 12c, or separately at the inlet flow path portion 12a and the outlet flow path.部 12c. 12c. By arranging the filter 15 in the outlet flow path portion 12c, even if a pulsation occurs, it can be a structure that is not easily affected by the pulsation. The configuration of the filter 15 provided in the outlet flow path portion 12c is the same as that provided in the inlet flow path portion 12a.

The ultrasonic gas flow meter of this embodiment has been described above, but the present invention is not limited to this embodiment, and can be changed in a variety of ways within the scope of the invention.

Claims (1)

A gas flowmeter includes: a main body, a series of gas flow paths formed from a gas inlet to a gas outlet are formed inside, and the bottom surface is open; a bottom cover is disposed on the bottom surface of the main body, covering the foregoing The main body body is closed on the bottom surface side to close the gas flow path; a measurement unit is disposed in the gas flow path, and is configured by assembling a sensor to a cylindrical flow path sleeve; and a filter is disposed on the Near the measurement unit, the flow of the gas flowing through the gas flow path is rectified; the filter has: a cylindrical member having an outer peripheral shape corresponding to an inner wall surface of the gas flow path; and an end wall, which is in contact with the cylinder One end of the member is connected and provided with an opening serving as a gas passage; the filter is accommodated and held by the inner wall surface of the gas flow path; the gas flow path is composed of an inlet flow path portion and the gas The inflow port communicates with the outlet flow path section and communicates with the gas flow outlet; and the intermediate flow path section communicates with the inlet flow path section and the outlet flow path section, respectively. The measurement unit is communicated with and accommodated; the gas flow path is provided with a U-shaped curved flow path shape; the filter is disposed in one or both of the inlet flow path part and the outlet flow path part The filter is embedded in the flow path portion such that the end wall is located at the upper end of the tube member; the lower end of the filter is held by a receiving portion formed in the bottom cover.