JP2547225Y2 - Inside and outside ventilation structure in gas meter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stores an internal and external ventilation structure of a gas meter, particularly, emergency shut-off devices including a pressure sensor inside a casing, and receives signal information from these internal devices via a lead wire. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inside / outside ventilation structure for constantly keeping the inside and outside pressures of a container in a gas meter which can be taken out to the outside.

[0002]

2. Description of the Related Art Recent gas meters, such as fluidic gas meters, not only have a gas measuring mechanism and a display mechanism but also, for example, to detect an abnormal flow rate of a gas to ensure various safety. Emergency shut-off devices such as a flow sensor, a seismic sensor, a pressure sensor, and a shut-off valve are installed to prevent a gas accident when an earthquake of a specified seismic intensity or higher is detected. Also, recently, lead wires from these devices are led out of the meter casing at appropriate locations in a sealed state, and connected to an external line such as an external signal line as necessary, so that emergency disconnection and remote opening / closing can be performed. A system for performing automatic meter reading and the like is being constructed.

[0003] In such a gas meter, since the above-mentioned built-in equipment particularly includes a pressure sensor, it is necessary to balance the back pressure with the atmospheric pressure. It is necessary to provide a ventilation structure to the casing so as to always keep the same.

Conventionally, as such a ventilation structure, one or a plurality of slit-shaped ventilation holes opened on the lower surface side are provided in a back cover that closes a space for accommodating lead wires provided on the back of the meter casing. It is common to correspond by forming.

[0005]

However, the conventional ventilation structure has the following problems. That is, although the ventilation holes are formed as small slits having a width of about 2 mm and a length of about 7 mm, invasion of small insects such as small ants and spiders cannot be prevented. For example, there is a possibility that an electrical trouble may occur such as corrosion of an electronic component caused by formic acid or a functional failure of a printed circuit board. In addition, gas meters are generally installed outdoors, such as in the garden, but in the summertime the inside of the gas meter may reach a high temperature of 60 ° C.
In such a high-temperature state, when water is sprayed nearby or when the water is wet due to a sunset, the gas meter is rapidly cooled and the inside of the casing is rapidly decompressed. In particular, water droplets and moisture are sucked in vigorously, which causes electrical troubles such as dielectric breakdown and rust on built-in electronic devices and printed circuit boards, etc., which causes failures and shortens the life of built-in devices. There was such a problem.

An object of the present invention is to provide an inside / outside ventilation structure that solves the above problems.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided, for the above object, firstly, an outer ventilation hole and an inner ventilation hole which are arranged with a sufficient distance between the ventilation holes in a vertical direction. And the opening area of the inner ventilation hole
That the as a larger than that of the outer vent was assumed capable of reliably preventing the intake invasion of rainwater, and a second
In addition, a filter made of a wire mesh is applied to the inner ventilation hole so that the invasion of insects can be surely prevented.

Thus, according to the present invention, devices including a pressure sensor (3) are stored in a casing (1).
Recess on the rear surface position of the casing (1) (6) is formed, and the opening surface of the recessed portion between the lead wire yield Osamesora by being closed is (9) formed in the back cover (8) In the gas meter, at the lower end of the lead wire storage space (9),
An outer ventilation hole (12) opening downward is formed between the back cover (8) and the casing (1), and at least 20 mm upward from the outer ventilation hole in the lead wire storage space.
Height retardation at a position spaced, casing (1) through the back wall of the recessed portion (6) and communicates with the interior, and the outer
Wherein the side vent (12) substantially effective opening area than a small inner vent hole (14) is bored formed, on the inner vent, that filter comprising non rust wire mesh (15) is mounted The outline of the inside and outside ventilation structure of the gas meter is as follows.

[0009] From the outer ventilation hole (12) to the inner ventilation hole (1).
The distance up to 4) is preferably set to 20 mm or more, particularly preferably 40 mm or more. That is, if this distance is less than 20 mm, water from the outside may still enter the gas meter due to the action of the sudden suction force. However,
The above distance does not necessarily have to be a linear distance.
If the path between the two ventilation holes is bent, the above-described distance may be set as the total length of the bent path.

On the other hand, if the mesh of the filter (15) is too fine, the airflow resistance increases, and the pressure equilibrium speed between the inside and outside decreases. Conversely, if it is too coarse, it will be insufficient to prevent insects from entering. Therefore, 40 to 100 mesh (Ty
lar), especially in the range of 50-60 mesh.

[0011] Other, inner vent hole (14), 20 mm ² or more in area occupied by the filter (15), set in particular 25 mm ² or more, and is preferably a circular one. On the other hand, the outer ventilation hole (12) needs to be formed larger than the inner ventilation hole (14).
In addition, it is desirable to have an opening area of at least 30 mm ² or more, preferably 50 mm ² or more. Of course, the number of the ventilation holes is not limited to one, and a plurality of ventilation holes may be provided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrated embodiment shows a fluidic gas meter as an example of a gas meter to which the present invention is applied. A fluidic vibration element, a flow rate detecting sensor and a seismic sensor (2) are provided in a casing (1). , A pressure sensor (3), a shutoff valve (4), a display unit (5), electronic circuit boards, and other necessary weighing and safety function devices.

In the casing (1), a recess having a predetermined size and depth, that is, a recessed portion (6) is formed at one side of the lower end of the back surface. Then, the opening surface of the recess (6) is closed by the back cover (8) via the packing (7), so that a lead wire storage space (9) having a required volume is formed inside the back cover (8). Have been. In this lead wire storage space (9), a lead wire (10) from storage equipment in the casing (1) is inserted into a lead wire drawing hole (11) drilled in the top wall portion of the recess (6). ), And after being drawn out, the lead-out hole (11) is hermetically closed using a suitable sealing material around the lead wire group. The entire lead wire (10) is stored in the storage space (9) when not in use, and a surplus portion of its length when connected to an external line.

At the lower end of the lead wire storage space (9),
Outer vent (1)
2) (see FIG. 3). That is, as shown in FIG. 1, the inwardly curved edge (8a) at the lower end of the back cover (8)
By cutting out the middle part, the notch (1
3), a laterally rectangular outer ventilation hole (12) is formed between the casing and the lower edge of the casing (1). Incidentally, the outer ventilation hole (12) has a size of 23 mm × 6 mm as an example and an effective opening area of 138 mm ² , but if it has a substantial effective opening area of at least 30 mm ² or more. good. Needless to say, the outer ventilation hole (12) may be formed by dividing the outer ventilation hole (12) into two or more, and have a total area of 30 mm ² or more. Preferably, it has an opening area of 50 mm ² or more, more preferably 100 mm ² or more.

On the other hand, at the upper end of the lead wire storage space (9), a circular inner ventilation hole (14) communicating with the inside and outside by drilling a deep wall portion of the recess (6) of the casing (1). (FIG. 4) is formed. A filter (15) is mounted in the inner ventilation hole (14). The filter (15) is made of a wire mesh made of a non-rusting metal such as stainless steel, and has a mounting elastic ring (16) integrally formed on the periphery thereof, utilizing the elasticity of the elastic ring (16). Is tightly fitted to the inner ventilation hole (14) so that it is not easily dropped off.

The wire mesh of the filter (15) is 40 to
100 mesh, preferably 50 to 60 mesh is used. The area of the vent hole (14) occupied by the filter (15) needs to be 20 mm ² or more as described above.
2.5%) due to substantially vent effective area 10 mm ² or more, and particularly preferably set to about 14~26mm ^2. If this is too small, the flow resistance of the air increases, causing a delay in the pressure equilibrium speed inside and outside the casing, and the pressure sensor (3)
This is not preferable because it may cause malfunction of the device. Conversely, being too large is useless. Incidentally, volume 1000 cc, in a state where the temperature of the internal ambient temperature of the casing 60 ° C. which was virtually vent effective area 17 mm ² of the vent hole (14),
Room temperature (20 ° C.) was applied to the casing to rapidly cool the internal atmosphere temperature to about 40 ° C., and the pressure fluctuation in the casing was measured. As shown in FIG. It has been confirmed that equilibrium can be achieved.

Incidentally, the inner ventilation hole (14) is
Located above the pores (12) and at least 20 mm high
It is necessary to have a phase difference.
2) The height phase difference (20 mm or less)
The upper distance is set. If this is too short, Ru difficult der to sufficiently prevent water from entering the vessel.

[0018]

In the gas meter according to the present invention, the inside and outside of the casing (1) are connected to the outside ventilation holes (1).
2), lead wire storage space (9) and inner ventilation hole (14)
Through the pressure sensor, the internal and external pressures are always balanced, and the back pressure of the pressure sensor (3) can be applied to the atmospheric pressure.

Further, the two ventilation holes (12) and (14) communicating the inside and the outside are provided at a predetermined distance from each other and with a phase difference in the height direction. Also, the presence of the lead wire storage space (9) having a relatively large volume between the two ventilation holes enables the seasonally heated gas meter to be sprinkled with water or cooled suddenly in the evening. Therefore, water is not unintentionally sucked into the casing, that is, the casing (1). That is, even if the suction force acts from the inner vent hole (14) due to the contraction of the internal air in the casing (1), the linear velocity of the suction air flow is relatively slow in the relatively large outer vent hole (12), and In addition to the fact that the amount of water droplets flowing down the outer surface and drawn into the lead wire storage space (9) can be small, even if some water droplets are drawn into the lead wire storage space (9), However, the air flow in the ascending direction in the space has a very low linear velocity, so that the water drops hardly flow upward in the space, and the inner air hole (14) is almost completely lost. Does not reach the position. Therefore, water is not drawn into the vessel from the inner ventilation hole (14), and it is possible to reliably prevent the troubles and failures caused by the above-described influence of the built-in devices from occurring.

The inside air hole (14) is provided with a wire mesh filter (15). Therefore, even small insects such as ants and spiders can be surely prevented from invading the casing (1), and it is possible to prevent electrical troubles and failures caused by the insects. The reliability and durability of the gas meter can be improved in combination with the above-described water intrusion prevention effect.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a back view of a gas meter with a back cover removed.

FIG. 2 is a front view of a lead wire storage space on the rear surface.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a perspective view showing an inner ventilation hole portion with a filter separated.

FIG. 5 is a graph showing a change state of an internal pressure in a quenching experiment of a casing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Casing 3 ... Pressure sensor 6 ... Depressed part 8 ... Back cover 9 ... Lead wire storage space 12 ... Outer ventilation hole 14 ... Inner ventilation hole 15 ... Filter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirokazu Kanda 1-70, Millennium, Atsuta-ku, Nagoya City, Aichi Prefecture Inside Aichi Watch Electric Co., Ltd. (72) Hideyuki Oike 1-2-2 Shimura, Itabashi-ku, Tokyo No. 3 Inside Kinmon Manufacturing Co., Ltd. (56) References JP-A-59-145891 (JP, A) JP-A-2-135820 (JP, U) JP-A 62-106116 (JP, U) JP-A Sho-56 −29196 (JP, U) Japanese Utility Model 2 14030 (JP, U) Japanese Utility Model 4 41629 (JP, U)

Claims (2)

(57) [Scope of request for utility model registration] An apparatus including a pressure sensor (3) is stored in a casing (1), and a concave portion (6) is formed at an appropriate position on a back surface of the casing (1), and an opening surface of the concave portion is provided. in the gas meter but that between the lead wires yield Osamesora by being closed (9) is formed by back cover (8), the lower end of the lead wire receiving space (9), the casing back cover (8) (1 ), A downwardly opening outer ventilation hole (12) is formed, and 20 mm upward from the outer ventilation hole in the lead wire storage space.
The positions at more than the height of the phase difference, the recessed portion casing through the back wall (6) (1) and communicates with the interior, and before
Kisotogawa vent is less substantial effective opening area than (12) <br/> inner vent holes (14) is bored formed, on the inner vent hole, made of non-rusting resistance wire mesh filter (1
5) An inside / outside ventilation structure in a gas meter, wherein the structure is mounted. 2. A filter (1) provided in an inner ventilation hole.
5) Is a wire mesh of 40 to 100 mesh (Tylar)
3. The gas vent structure according to claim 1, wherein the gas vent is a gas vent.