JP5236303B2 - Gas meter - Google Patents

Description

  The present invention relates to a gas meter including a flow path member, a measurement tube, ultrasonic wave propagation means, and flow rate calculation means.

The gas meter, for example, utilizes the fact that the propagation time or propagation speed of ultrasonic waves changes depending on the flow velocity of the gas (measuring fluid), and propagates the ultrasonic waves to the gas flowing in the measurement pipe (conduction path) to reduce the gas flow rate. Measuring. When measuring the flow rate, if the aspect of the gas flow in the measuring tube changes significantly, the measurement error tends to increase. Conventionally, in order to improve measurement accuracy, an example of a technique in which a rectifying plate that is divided into a plurality of layers so that the thickness (height in the stacking direction) is uniform is provided in a measurement tube (for example, Patent Document 1). See).
JP 2006-64626 A

  In the gas meter described in Patent Document 1, a measurement pipe is provided in the middle of a flow path member that becomes a flow path of gas from an inflow port to an outflow port. Since the gas flowing through the gas meter contains a lot of moisture, it may be stored as water at the bottom of the gas meter when the environmental conditions are met. However, when a large amount of water overflows into the measuring tube, the cross-sectional area of the gas that can pass through the measuring tube decreases. As a result, the capacity that can be rectified by the measuring tube is reduced, and the error may increase in measuring the gas flow rate.

  On the other hand, in order to reduce the measurement error of the flow rate, a method is conceivable in which the entire gas meter (particularly, the bottom) is formed so as not to affect the measurement even if water is stored. However, when the gas meter is simply enlarged, the weight of the gas meter increases, and the constituent members must be formed larger, resulting in higher costs.

  The present invention has been made in view of these points, and an object of the present invention is to provide a gas meter capable of maintaining the weight and manufacturing cost of the gas meter as usual while suppressing measurement errors in the flow rate to a small extent.

The present invention is as described in claim 1.
According to the present invention , the buffer unit stores water generated in the gas flow path. In other words, in addition to the capacity of water that can be stored conventionally, the capacity increases by the capacity of water stored in the buffer section. For this reason, it is possible to reduce a situation in which a large amount of stored water overflows into the measuring pipe, and hence it is possible to reduce flow measurement errors. Further, since the buffer unit has a function of fixing the measuring tube in cooperation with the flow path member, it is not necessary to simply enlarge the gas meter. Therefore, the weight and manufacturing cost of the gas meter can be maintained as usual.

Moreover, in this invention, the opening part is provided in the inflow port side of the buffer part. Since gas enters from the inlet, a lot of water is generated on the inlet side if environmental conditions such as temperature differences are prepared. Since the water thus generated can be guided from the opening portion to the buffer portion, it is possible to more reliably reduce the situation where the water overflows into the measuring tube. Therefore, the flow rate measurement error can be further reduced.

Further , according to the present invention , if the opening portion that leads to the gas flow path is closed by the closing member, the water can be discharged from the discharge port while preventing the gas from flowing out to the outside. Accordingly, by appropriately discharging water, it is possible to reliably prevent a situation in which water overflows into the measuring tube.

  According to the present invention, the weight and manufacturing cost of a gas meter can be maintained as usual while suppressing flow rate measurement errors to a minimum.

Next, an embodiment as a premise of the present invention will be described with reference to FIGS. The best mode for carrying out the present invention will be described with reference to FIGS.
FIG. 1 shows a front view of the gas meter according to the present invention, and FIG. 2 shows a plan view (top view). FIG. 3 is an exploded perspective view showing a configuration example of the gas meter. 4 represents a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 shows a cross-sectional view taken along line VV in FIG. 6 represents a cross-sectional view taken along line VI-VI in FIG.

  First, an appearance example of the gas meter 10 will be briefly described with reference to FIGS. 1 and 2. 1 and 2, a gas meter 10 formed in a substantially rectangular box shape is provided with a front panel member 16 on the front side. The front panel member 16 is provided with a return button 18, a display means 20, and the like. The return button 18 returns the shut-off valve 34 (see FIG. 3) that has been activated by abnormality detection to return from the shut-off state to the flow state. For example, a liquid crystal display, an LED display, or the like is used as the display means 20, and displays the integrated value of the measured gas flow rate, other information, and the like.

  As shown in FIG. 3, the gas meter 10 includes a front panel member 16, a control board 26, a power pack 28, a pressure sensor 30, and an ultrasonic wave propagation means 32 (that is, a pair of ultrasonic wave propagation devices 32 a, around the flow path member 22. 32b), current plate 36, 38, measuring tube 40, bottom panel member 42, and the like. The flow path member 22 is integrally formed by, for example, aluminum die casting, and appears on the upper surface and the left and right side surfaces in the appearance of the gas meter 10. The flow path member 22 forms a cylindrical, substantially U-shaped flow path in which the inflow port 12 and the outflow port 14 are arranged on the same surface (upper surface in this example). That is, the flow path of the gas flowing in from the inlet 12 and flowing out of the outlet 14 together with other members (for example, the front panel member 16, the back panel member 24 and the bottom panel member 42 described later) is substantially U-shaped. Become a shape.

  By the way, when the entire substantially cylindrical U-shape is integrally formed with only the flow path member, a part or member (hereinafter simply referred to as “part etc.”) can be attached to or removed from the cylinder. It becomes difficult. Therefore, the flow path member 22 is integrally formed by opening the bottom portion, and after attaching parts and the like from the bottom portion (that is, the opening portion), the bottom panel member 42 is used to cover (FIG. 3, FIG. 3). (See FIG. 4). With such a configuration, it is easy to attach or remove components or the like in the cylinder while the gas flow path is substantially U-shaped in a cylindrical shape.

  Various parts and the like are attached to the flow path member 22 configured as described above. In FIG. 3, the mounting directions of the components and the like are indicated by arrows. The front panel member 16, the control board 26, the power pack 28, the pressure sensor 30, the ultrasonic wave propagator 32a, and the like are attached to the flow path member 22 from the front side (left side in the drawing). The control board 26 (corresponding to “control means”) includes electronic control components such as a CPU and a memory, and controls the entire gas meter 10. As an example of the control, the flow rate of the gas flowing through the measuring tube 40 is calculated based on the detection signals output from the ultrasonic wave propagators 32a and 32b, and the calculated flow rate of the gas is displayed on the display means 20. As another control example, various abnormality determinations are performed based on the pressure output from the detection signal of the pressure sensor 30, and when the abnormality is determined, a drive signal is output to the shutoff valve 34 to block the flow path. .

  The power pack 28 is used as a power source for driving the control board 26 and other electronic components. The power pack 28 is attached to a space K provided in the substantially central portion of the flow path member 22. The pressure sensor 30 is used to detect various abnormalities, detects the pressure of the gas in the flow path, and outputs a detection signal. The pressure sensor 30 is attached to a dedicated attachment hole provided on the front side of the substantially U-shaped flow path of the flow path member 22. The ultrasonic wave propagation device 32 a constitutes one side of the ultrasonic wave propagation means 32.

  The shut-off valve 34, the ultrasonic wave propagator 32b, the back panel member 24, and the like are attached to the flow path member 22 from the back side (right side of the drawing). The shutoff valve 34 closes (shuts down) the flow path when an abnormality is detected, so that gas does not flow to the outlet 14. The shut-off valve 34 is attached to a dedicated attachment hole provided on the back side of the substantially U-shaped flow path of the flow path member 22. The ultrasonic wave propagation device 32 b constitutes the other side of the ultrasonic wave propagation means 32. The back panel member 24 is provided on the back side of the gas meter 10.

  The rectifying plates 36, 38, the measuring tube 40, the bottom panel member 42, and the like are attached to the flow path member 22 from the bottom surface side (the lower side in the drawing). As shown in FIGS. 4 and 5, the rectifying plate 36 regulates the flow of the gas flowing in from the inflow port 12 to some extent and guides it to the inflow port of the measuring tube 40. The rectifying plate 36 has a passage hole 36b and a rib 36a. The passage hole 36b is formed in, for example, a rectangular shape in accordance with the shape of the inlet of the measuring tube 40 (see FIG. 6). The rib 36a rises from the peripheral edge of the passage hole 36b toward the inlet 12 and has a predetermined height. As shown in FIG. 4, the rectifying plate 38 regulates the flow of the gas flowing out from the outlet of the measuring tube 40 to some extent and guides it to the outlet 14. This baffle plate 38 has a passage hole 38b and a rib 38a. The passage hole 38b is formed in the same shape as the passage hole 36b (see FIG. 6). The rib 38a rises from the peripheral edge of the passage hole 38b toward the outlet 14 and has a predetermined height. The predetermined height applied to the ribs 36a and 38a is appropriately determined by experiments or the like.

  In this example, the measuring tube 40 is attached so as to be sandwiched between the lower center portion of the flow path member 22 and the buffer portion 42a of the bottom panel member 42 so as to be disposed in the gas flow path. The measuring tube 40 is formed in a cylindrical shape in which the gas passage cross section is substantially rectangular, and a rectifying plate group 44 is provided in the tube. The rectifying plate group 44 is a member that rectifies the gas flowing in the measuring tube 40, and includes a plurality of rectifying plates arranged in parallel and in multiple layers. The bottom panel member 42 corresponds to a “fixing member” and is provided on the bottom side of the gas meter 10. As shown in FIGS. 3 and 4, the bottom panel member 42 has a buffer portion 42 a that is formed in a convex shape and can store water. One surface of the buffer portion 42a (the surface corresponding to the inlet 12 in this example) is provided with an opening portion 42b that leads to the gas flow path and guides water to the inside.

The ultrasonic propagation means 32 (ultrasonic transmission / reception sensor) will be briefly described. As shown in FIG. 6, the ultrasonic wave propagator 32a and the ultrasonic wave propagator 32b are arranged to face each other at predetermined positions on the upstream side and the downstream side in the gas meter 10, and have a predetermined amount with respect to the gas flow direction. Provided at an angle “θ”. An ultrasonic wave is output from one of the ultrasonic wave propagators, the ultrasonic wave is received by the other ultrasonic wave propagator, and the propagation time is measured. Both the propagation from the upstream side to the downstream side and the propagation from the downstream side to the upstream side are performed to obtain the flow velocity and flow rate of the gas. Here, when the sound velocity is “C”, the distance between the ultrasonic wave propagators 32a and 32b is “L”, and the ultrasonic wave propagation time is “T1” and “T2”, the gas flow velocity “U” is as follows. It is calculated by the formula. Further, when the cross-sectional area and the flow coefficient of the measuring tube 40 are integrated with the calculated flow velocity “U”, the gas flow rate is obtained. The flow coefficient is a coefficient for correcting the flow rate of the fluid.
U = (L / 2 cos θ) × {(1 / T1) − (1 / T2)}

According to the embodiment described above, the following effects can be obtained.
(1) The bottom panel member 42 includes a buffer part 42a that can store water through the gas flow path, and is configured to fix the measurement tube 40 between the buffer part 42a and the flow path member 22 ( (See FIGS. 3 and 4). According to this configuration, in addition to the capacity of water that can be stored conventionally, the capacity is increased by the capacity of water stored in the buffer unit 42a. For this reason, a situation in which a large amount of stored water overflows into the measuring tube 40 can be reduced, so that a flow measurement error can be reduced.
Moreover, since the buffer part 42a has a function of fixing the measuring tube 40 in cooperation with the flow path member 22, it is not necessary to simply enlarge the gas meter 10. Therefore, the weight and manufacturing cost of the gas meter 10 can be maintained as usual.
Furthermore, the buffer part 42a has a space where not only water but also gas can enter, and this space itself also has a heat insulating function. Therefore, since the temperature change given to the measuring tube 40 can be reduced, the flow rate measurement error caused by the temperature change can be further reduced.

(2) Since gas enters from the inlet 12, if environmental conditions such as a temperature difference are prepared, a large amount of water is generated in the gas flow path on the inlet 12 side. Therefore, the buffer portion 42a on the inlet 12 side is opened to provide an opening portion 42b (see FIGS. 3 and 4). According to this configuration, since the generated water can be guided into the buffer portion 42a from the opening portion 42b, the situation where the water overflows into the measuring tube 40 can be more reliably reduced. Therefore, the flow rate measurement error can be further reduced.

[Other Embodiments]
Has been described in terms of preferred embodiments as a premise of the present invention in the above may realize each embodiment shown below.

(1) In the above-described embodiment, the buffer portion 42a is formed integrally with the bottom panel member 42 (see FIGS. 3 and 4). Instead of this configuration, a planar bottom panel member 42 and a box-shaped buffer 42a having an opening 42b may be formed separately. In this case, the buffer part 42a may be fixed to the bottom panel member 42 by a predetermined fixing method (for example, bonding, welding, fastening using a fastening member, etc.). Even in this case, since the buffer portion 42a does not change the point of storing water, the same effects as those of the above-described embodiment can be obtained. Further, when the buffer portion 42a is formed separately, it can be attached to a conventional gas meter, so that the flow measurement error can be reduced at a low cost.

(2) In the above-described embodiment, the buffer portion 42a is formed on the upper surface of the bottom panel member 42 (FIGS. 3 and 4). Instead of this form, a concave portion 42c as shown in FIG. 7 may be formed together with the buffer portion 42a. Since the bottom surface is lowered by this concave portion 42c and the water storage capacity can be increased, the situation where water overflows into the measuring tube 40 can be reduced more reliably. Therefore, the measurement error of the flow rate can be reduced more reliably.

(3) Now, in the embodiment of the present invention, as shown in FIG. 8, the bottom panel member 42 may be provided with a discharge port 42f that is closed using a plug 42e. Although the water can be drained by removing the stopper 42e, the buffer portion 42a is filled with gas because it passes through the gas flow path. Therefore, when the discharge port 42f is provided, it is necessary to separately provide a closing member 42d for closing the opening portion 42b. When water is stored, the closing member 42d does not close the opening portion 42b (for example, slide), and when water is discharged, the closing member 42d closes the opening portion 42b and then removes the plug 42e. It is even better if the closing member 42d and the stopper 42e operate in conjunction with each other. If the discharge port 42f is provided in this way, water can be discharged when the buffer portion 42a is full, and flow measurement errors can be reduced.

(4) In the above-described embodiment, the buffer portion 42a on the inlet 12 side is opened to provide the opening portion 42b (see FIGS. 3 and 4). Instead of this configuration, the buffer portion 42a on the outlet 14 side may be opened to provide an opening portion. Since the generated water can be led into the buffer part 42a in the gas flow path on the outlet 14 side, the situation where water overflows into the measuring tube 40 can be reduced more reliably. Therefore, the flow rate measurement error can be reduced as compared with the conventional case.

(5) In the above-described embodiment, the opening portion 42b of the buffer portion 42a is provided only on the inlet 12 side (see FIGS. 3 and 4). In the above (4), the opening portion 42b of the buffer portion 42a is flowed. It was set as the structure provided only in the exit 14 side. Instead of this configuration, as shown in FIGS. 9 and 10, the opening 42 b of the buffer 42 a may be provided on both the inlet 12 side and the outlet 14 side. 9A shows a side view of the bottom panel member 42 viewed from the inlet 12 side, FIG. 9B shows a side view of the bottom panel member 42 viewed from the outlet 14 side, and FIG. FIG. 10A is a cross-sectional view taken along line XX in FIG.

  As shown in FIG. 9 (A) and FIG. 9 (B), since there are opening portions 42b on both the inlet 12 side and the outlet 14 side, even if water is generated on both sides, it is stored in the buffer portion 42a. be able to. However, as shown in FIG. 10, since the buffer part 42a is divided by the inflow port 12 side and the outflow port 14 side, the water and gas which flowed in from one opening part 42b flow out from the other opening part 42b. There is no. According to this configuration, since the water generated on both the inlet 12 side and the outlet 14 side is reliably stored, the situation where water overflows into the measuring tube 40 is reduced, and the flow rate measurement error is more reliably performed. Can be reduced.

It is a front view showing the example of appearance of a gas meter. It is a top view showing the external appearance example of a gas meter. It is a disassembled perspective view explaining the structural example of a gas meter. It is sectional drawing of the IV-IV line arrow in FIG. It is sectional drawing of the VV arrow in FIG. It is sectional drawing of the VI-VI line arrow in FIG. It is sectional drawing showing the example comprised using the fixing member which formed the bottom face in the concave shape. It is sectional drawing showing the example comprised using the fixing member in which the discharge port was formed. It is a side view showing the bottom panel member which has a buffer part which opened both the inflow port side and the outflow port side. It is sectional drawing of the XX arrow in FIG. 9 (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gas meter 12 Inlet 14 Outlet 16 Front panel member 18 Return button 20 Display means 22 Flow path member 24 Back panel member 26 Control board 28 Power supply pack 30 Pressure sensor 32 Ultrasonic propagation means 32a, 32b Ultrasonic wave propagation device 34 Shut-off valve 36, 38 Current plate 36a, 38a Rib (head)
36b, 38b Passage hole 40 Measuring tube 42 Bottom panel member (fixing member)
42a Buffer part 42b Opening part 42c Concave part 42d Closing member 42e Plug 42f Discharge port 44 Current plate group K Space part

Claims (1)

A channel member formed in a substantially U-shaped cylindrical shape as a gas channel from the inlet to the outlet;
A measuring tube disposed in the gas flow path formed by the flow path member and formed so that the gas passage cross section is substantially rectangular;
A pair of ultrasonic wave propagation means for propagating the ultrasonic wave between two predetermined points provided on the upstream side and the downstream side in the measurement tube and outputting a detection signal;
A gas meter comprising flow rate calculation means for calculating a flow rate of the gas flowing in the measurement tube based on a detection signal output from the ultrasonic wave propagation means,
A buffer part capable of storing water through the gas flow path, and having a fixing member for fixing the measurement tube between the buffer part and the flow path member;
The buffer portion of the fixing member is a gas meter including an opening portion that opens an inflow side that communicates with a gas flow path, a closing member that closes the opening portion, and a discharge port that discharges stored water .

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