JP7036648B2 - Flow measuring device - Google Patents

Description

The present invention relates to a flow rate measuring device.

Conventionally, as one of the flow rate measuring devices, a straight tube type gas meter in which a gas inlet and a gas outlet are linearly arranged has been proposed. This straight tube type gas meter is equipped with a gas flow path that extends in a substantially predetermined direction from the gas inlet to the gas outlet, and a flow velocity sensor for measuring the flow rate of the gas flowing through the gas flow path. It is configured to integrate and display the gas flow rate based on the flow velocity measured by (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-173200

The straight pipe type gas meter as described in Patent Document 1 is designed for the purpose of miniaturization, and since the meter is a part of the pipe itself, the pressure fluctuation due to the use of gas equipment etc. is used as the flow velocity change as it is. It will be easier to measure. In particular, when the isolation valve is configured by a ball valve as described in Patent Document 1, since the gas flow path has a completely straight structure, the flow velocity fluctuation generated by the pressure fluctuation is more likely to become apparent in the immediate vicinity of the measurement unit. .. Therefore, there is a possibility that the error of the flow rate measurement becomes large.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a flow rate measuring device capable of reducing a measurement error.

The flow rate measuring device of the present invention includes a gas inlet, a gas outlet, a gas flow path extending in a substantially predetermined direction from the gas inlet to the gas outlet, a flow velocity sensor for measuring the gas flow rate, and a flow velocity sensor. It is equipped with a shutoff valve that shuts off the gas flow rate. Further, the gas flow path has a bent structure having a bent portion from the gas inlet to the gas outlet, and the direction of the bent portion on the downstream side of the isolation valve is orthogonal to a substantially predetermined direction. The cross-sectional area of the flow path is equal to or greater than the cross -sectional area in the direction orthogonal to the substantially predetermined direction of the flow path portion where the flow rate of gas is measured by the flow velocity sensor. Further, the shutoff valve can be transitioned between a valve closed state in which the valve projects in a direction orthogonal to a predetermined direction to close the opening and a valve open state in which the valve operates in the direction opposite to the protruding direction to open the opening. The gas flow path has an opening area equal to or larger than the cross-sectional area in a direction orthogonal to a substantially predetermined direction of the flow path portion.

According to the present invention, since the gas flow path has a bent structure having a bent portion, it is not directly affected by the pressure fluctuation unlike the completely straight structure, and is affected by the pressure fluctuation at the bent portion. Can be alleviated. In particular, since the cross-sectional area of the flow path on the downstream side of the isolation valve in the bent portion is equal to or larger than the cross-sectional area of the flow path portion where the gas flow rate is measured by the flow velocity sensor, the flow path volume at the bent portion is secured. However, it is possible to reduce the measurement error by alleviating the pressure fluctuation in this volume portion.

It is external perspective view of the straight tube type gas meter which concerns on this embodiment. It is a partial sectional view which shows the outline of the internal structure of the straight tube type gas meter which concerns on this embodiment. It is a graph which shows the flow rate value measured at the time of a pressure fluctuation. It is a partial cross-sectional view which shows the outline of the internal structure of the straight tube type gas meter which concerns on a modification.

Hereinafter, the present invention will be described with reference to preferred embodiments. The present invention is not limited to the embodiments shown below, and can be appropriately modified without departing from the spirit of the present invention. Further, in the embodiments shown below, some parts of the configuration are omitted from the illustration and description, but the details of the omitted technology are within the range where there is no contradiction with the contents described below. Needless to say, publicly known or well-known techniques are applied as appropriate. In addition, in the following, a straight tube type gas meter having a straight tube shape in outer shape will be described as an example of a flow rate measuring device, but the flow rate measuring device is not limited to the straight tube type gas meter.

FIG. 1 is an external perspective view of a straight-tube gas meter according to the present embodiment, and FIG. 2 is a partial cross-sectional view showing an outline of an internal configuration of the straight-tube gas meter according to the present embodiment.

The straight tube type gas meter 1 shown in FIGS. 1 and 2 includes a meter body (body) 10 which is a housing formed of a metal material such as aluminum or an aluminum alloy. The meter body 10 has a substantially square columnar outer shape, and has a straight tube shape that is longitudinal in the height direction of the square column. In the example shown in FIG. 1, the meter body 10 is installed so that its longitudinal direction coincides with the vertical direction, but the present invention is not limited to this, and the meter body 10 may be installed so that its longitudinal direction coincides with the horizontal direction.

The meter body 10 includes a gas inlet 11 for introducing gas into one end 10a in the longitudinal direction thereof, and a gas outlet 12 for discharging gas to the other end 10b in the longitudinal direction thereof. The gas inlet 11 is connected to the gas supply source via the upstream pipe 20, and the gas outlet 12 is connected to the gas supply destination via the downstream pipe 21. For the connection between the gas inlet 11 and the upstream pipe 20 and the connection between the gas outlet 12 and the downstream pipe 21, for example, a joint structure 15 that can be disconnected by a one-touch operation (that is, only a pushing operation) is adopted. ing.

Inside the meter body 10, one gas flow path 13 extending in a substantially predetermined direction (longitudinal direction of the meter body 10) is formed from the gas inlet 11 to the gas outlet 12. The gas flow path 13 has a bent structure having a bent portion BP extending in a direction orthogonal to the longitudinal direction of the meter body 10 between the gas inlet 11 and the gas outlet 12. In addition, "extending in a substantially predetermined direction" means that when the total of the flow path lengths of the flow paths extending in the predetermined direction and the total flow path lengths of the flow paths extending in other directions are compared, it is in the predetermined direction. It means that the total of the flow path lengths of the extending flow paths is larger than the total of the flow path lengths of the flow paths extending in other directions.

Further, the straight tube type gas meter 1 according to the present embodiment includes the display panel 2 shown in FIG. 1, the multilayer unit 3 shown in FIG. 2, the flow velocity sensor 4, the isolation valve 5, and the like.

The display panel 2 shown in FIG. 1 is composed of an LCD or the like, and is provided on the front portion 10c of the meter body 10. The display panel 2 is controlled by a microcomputer (not shown) and displays information processed by the microcomputer. The typical information displayed on the display panel 2 is an integrated value (integrated flow rate) of the gas flow rate based on the measured value measured by the flow velocity sensor 4.

The multilayer unit 3 shown in FIG. 2 is a tubular body having a substantially quadrangular cross section that forms a measurement flow path inside the multi-layer unit 3. The multilayer unit 3 is integrally provided with a plurality of partition plates 3a for dividing the measurement flow path inside the cylindrical body. The gas flowing inside the multilayer unit 3 is rectified by these partition plates 3a. In the multilayer unit 3, for example, the partition plate 3a is made of metal, and the others are made of resin or the like.

The flow velocity sensors 4 are two acoustic transducers arranged so as to be separated from each other by a predetermined distance with the gas flow path 13 (multilayer unit 3) interposed therebetween and to form an angle θ with respect to the gas flow direction Y. It has TD1 and TD2. The microcomputer drives one of the transducers TD1 and TD2 to intermittently transmit an ultrasonic signal from the one to the gas flow path 13. The other of the transducers TD1 and TD2 receives an ultrasonic signal. The microcomputer causes the above operation to be performed from both the upstream side and the downstream side with respect to the gas flow direction Y, and calculates the gas flow velocity based on the difference in the propagation time of the ultrasonic signal regarding the transmission and reception. Further, the microcomputer measures the gas flow rate based on the calculated gas flow rate.

Although the partition plate 3a and the transmission / reception direction of the ultrasonic signal are shown to intersect with each other in FIG. 2, they are actually in a parallel relationship so that the partition plate 3a does not interfere with the transmission / reception of the ultrasonic signal. It is installed in.

The shutoff valve 5 shuts off the gas flow path 13 on the upstream side of the flow velocity sensor 4 in the gas flow path 13, and is installed at the bent portion BP of the gas flow path 13. A circular opening (opening) OP is formed between the upstream side and the downstream side of the bent portion BP, and the isolation valve 5 projects in the orthogonal direction (extending direction of the bent portion BP) and has a circular opening OP. It is possible to make a transition between the valve closed state that closes the valve and the valve open state that operates in the direction opposite to the protruding direction to open the circular opening OP.

Further, in the present embodiment, the straight tube type gas meter 1 adopts the following two configurations in order to prevent other consumers from measuring pressure fluctuations such as when using gas appliances as flow velocity changes as they are. ing. The first is that, as described above, the gas flow path 13 is not completely straight and is provided with a bent portion BP. By providing such a bent portion BP, it is possible to prevent the flow velocity fluctuation generated by the pressure fluctuation from becoming more apparent in the multilayer unit 3 as in the case of the straight shape. The second is that the volume of the bent portion BP on the downstream side of the isolation valve 5 is secured to a predetermined value or more. That is, the straight pipe type gas meter 1 according to the present embodiment has a large volume by providing a bent portion BP in the gas flow path 13 and increasing the volume of the bent portion BP on the downstream side of the isolation valve 5. The unit functions as a buffer against pressure fluctuations. The straight tube type gas meter 1 adopts the following configuration in order to form such a large volume portion.

First, in the present embodiment, in the gas flow path 13, the cross-sectional area SA1 (cross section orthogonal to the longitudinal direction of the meter body 10) on the downstream side of the isolation valve 5 in the bent portion BP is abbreviated as the cross-sectional area SA2 of the multilayer unit 3. It is said to be the same. In this way, the cross-sectional area SA1 on the downstream side of the isolation valve 5 is substantially the same as the cross-sectional area SA2 of the multilayer unit 3, so that the volume of the bent portion BP on the downstream side of the isolation valve 5 is secured. ..

Further, in the present embodiment, the multi-layer unit also has a cross-sectional area SA3 of the portion of the gas flow path 13 from the bent portion BP to the multi-layer unit 3 (for example, the flow path 13a extending slightly inclined with respect to the longitudinal direction). It is said to be substantially the same as the cross-sectional area SA2 of 3. Therefore, the gas flow path 13 has a substantially uniform cross-sectional area without being narrowed down from the downstream side of the bent portion BP to the multilayer unit 3.

The cross-sectional area SA1 on the downstream side of the isolation valve 5 in the bent portion BP and the cross-sectional area SA3 of the portion of the gas flow path 13 from the bent portion BP to the multilayer unit 3 are the cross-sectional areas of the multilayer unit 3. It may be larger than SA2.

Further, in the present embodiment, the circular opening OP formed in the bent portion BP has an opening area of SA2 or more in cross-sectional area of the multilayer unit 3. By increasing the circular opening OP to some extent in this way, it is easy to secure the volume on the downstream side located immediately below the circular opening OP. That is, if the circular opening OP is small, the volume on the downstream side is also reduced accordingly, making it difficult to secure the volume. However, in the straight tube type gas meter 1 according to the present embodiment, by increasing the circular opening OP to some extent, it is easy to secure the volume on the downstream side according to the size of the circular opening OP.

In addition, in the present embodiment, the bent portion BP has a recessed portion 6 recessed in the valve moving direction when the isolation valve 5 is closed. That is, the bent portion BP has a recessed portion 6 formed so that the garden wall BP1 on the downstream side is hollowed out. With such a recessed portion 6, the volume on the downstream side is expanded so as to further function as a buffering portion against pressure fluctuations.

Here, the depth of the recessed portion 6 is set to a certain value (for example, 3 mm) or less. FIG. 3 is a graph showing the flow rate value measured at the time of pressure fluctuation. In the example shown in FIG. 3, the case where the recessed portion 6 of φ28 is formed is shown, and the true value of the flow rate is assumed to be 0 L / h.

As shown in FIG. 3, when the recess 6 is not present (that is, when the depth is 0 mm), the flow rate is measured at −0.7 L / h for a pressure fluctuation of 7.5 Hz, and the pressure fluctuation is 10 Hz. -1.0 L / h is measured, and -0.2 L / h is measured for a pressure fluctuation of 11.66 Hz. Further, -0.3 L / h is measured for a pressure fluctuation of 13.3 Hz, 0.3 L / h is measured for a pressure fluctuation of 17.5 Hz, and 0. 5 L / h is measured, and 0.2 L / h is measured for a pressure fluctuation of 50 Hz.

On the other hand, when the depth of the recess 6 is 3 mm and the depth is 13 mm, the flow rate approaches 0 L / h for a pressure fluctuation of 7.5 Hz to 11.66 Hz. Therefore, it was found that by providing the recessed portion 6 in the garden wall BP1 of the bent portion BP, the influence of the pressure fluctuation can be mitigated and the measurement error can be reduced.

Further, as shown in FIG. 3, there was almost no difference in the degree of mitigation of the influence of the pressure fluctuation between the case where the depth of the recess 6 was 3 mm and the case where the depth was 13 mm. Therefore, it was found that the depth of the recessed portion 6 of φ28 does not need to exceed 3 mm, and a constant value is sufficient for the depth of the recessed portion 6.

In the present embodiment, the recessed portion 6 is formed so that the entire garden wall BP1 is hollowed out, but the present invention is not limited to this, and the recessed portion 6 is formed so that only a part of the garden wall BP1 is hollowed out. You may be.

Next, the operation of the straight tube type gas meter 1 according to the present embodiment will be described. For example, it is assumed that a gas appliance is used by another consumer and the pressure fluctuation generated at that time reaches the upstream side of the straight pipe type gas meter 1.

In this case, the pressure fluctuation (that is, the vibration of the gas) also acts on the gas in the gas flow path 13 from the gas inlet 11. However, in the present embodiment, the bent portion BP is provided in the gas flow path 13. Further, a volume of a certain amount or more is secured in the portion of the bent portion BP on the downstream side of the isolation valve 5. That is, the cross-sectional area SA1 at the site is set to be equal to or larger than the cross-sectional area SA2 of the multilayer unit 3, and the size of the circular opening OP of the bent portion BP is also set to be equal to or larger than the cross-sectional area SA2 of the multilayer unit 3. Therefore, the presence of the bent portion BP and the securing of a certain volume or more suppress the pressure fluctuation and alleviate the influence on the multilayer unit 3. As a result, it is possible to reduce the measurement error due to the pressure fluctuation.

In this way, according to the straight tube type gas meter 1 according to the present embodiment, since the gas flow path 13 has a bent structure having a bent portion BP, it is affected by pressure fluctuation like a completely straight structure. It is not received as it is, and the influence of pressure fluctuation can be mitigated at the bent portion BP. In particular, since the flow path cross-sectional area SA1 on the downstream side of the isolation valve 5 of the bent portion BP is set to be equal to or larger than the cross-sectional area SA2 of the multilayer unit 3, the flow path volume in the bent portion BP is secured, and this volume portion is secured. It is possible to alleviate pressure fluctuations and reduce measurement errors.

Further, since the area of the circular opening OP is set to be equal to or larger than the cross-sectional area SA2 of the multilayer unit 3, it is prevented that the circular opening OP becomes small and it becomes difficult to secure the flow path volume in the bent portion BP, and an appropriate measurement error is obtained. Can be reduced.

Further, since the bent portion BP has a recessed portion 6 recessed in the valve moving direction when the isolation valve 5 is closed, the recessed portion 6 increases the flow path volume in the bent portion BP, and more appropriately measures an error. Can be reduced.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and changes may be made without departing from the spirit of the present invention, and other examples may be made as appropriate. Techniques may be combined.

For example, in the above embodiment, the isolation valve 5 has been described assuming a motor valve, but the description is not limited to this, and the isolation valve 5 may be configured by another type of valve such as a solenoid valve. Further, in the present embodiment, the ultrasonic flow velocity sensor is provided as the flow velocity sensor 4, but if possible, another type of sensor such as a flow sensor may be used.

In addition, the straight tube type gas meter according to the present embodiment may have the configuration shown in FIG. FIG. 4 is a partial cross-sectional view showing an outline of the internal configuration of the straight tube type gas meter according to the modified example. As shown in FIG. 4, in the straight tube type gas meter 2 according to the modified example, the flow path 13a extending slightly inclined with respect to the longitudinal direction is provided not on the upstream side but on the downstream side of the multilayer unit 3. As described above, the gas flow path 13 may be configured to be bent in an oblique direction on the downstream side of the multilayer unit 3.

Further, in the above embodiment, the straight tube type gas meter 1 in which the meter body 10 has a straight tube shape has been described as an example of the flow rate measuring device, but the body shape is not limited to the straight tube type and may be a box type or the like. There may be. Further, in the above embodiment, the straight tube type gas meter 1 having a meter function for displaying the measured flow rate has been described as an example of the flow rate measuring device, but the flow rate measuring device is not limited to this, and the flow rate measuring device has a function of displaying the measured flow rate. You do not have to have it. Further, as long as the flow velocity sensor 4 for measuring the gas flow rate is provided, not only the flow rate but also only the flow velocity may be measured.

1: Straight tube type gas meter (flow rate measuring device)
3: Multi-layer unit 4: Flow velocity sensor 5: Isolation valve 6: Indentation 10: Meter body (body)
11: Gas inlet 12: Gas outlet 13: Gas flow path BP: Bending part OP: Circular opening

Claims (2)

A gas inlet and a gas outlet formed in the body for introducing gas and a gas outlet for discharging gas, a gas flow path extending in a substantially predetermined direction from the gas inlet to the gas outlet, and a gas flowing through the gas flow path. It is a flow rate measuring device equipped with a flow velocity sensor for measuring the flow rate of the gas.
A shutoff valve for shutting off the gas flow path is provided on the upstream side of the flow velocity sensor.
The gas flow path has a bent structure extending from the gas inlet to the gas outlet in a direction orthogonal to the substantially predetermined direction and having a bent portion in which the isolation valve is installed. The cross-sectional area of the flow path in the direction orthogonal to the substantially predetermined direction on the downstream side of the isolation valve of the bent portion is the same as the roughly predetermined direction of the flow path portion where the flow rate of gas is measured by the flow velocity sensor. It is considered to be more than the cross-sectional area in the orthogonal direction ,
The isolation valve can be transitioned between a valve closed state in which the valve protrudes in a direction orthogonal to the substantially predetermined direction to close the opening and a valve open state in which the valve operates in the direction opposite to the protruding direction to open the opening. ,
The gas flow path is a flow rate measuring device, wherein the area of the opening is equal to or larger than the cross-sectional area of the flow path portion in a direction orthogonal to the substantially predetermined direction . The flow rate measuring device according to claim 1 , wherein the bent portion has a recessed portion in the valve moving direction when the shutoff valve is closed.

Images