JP2017049075A - Membrane gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane gas meter capable of reducing pressure loss of gas on an inlet side as much as possible.SOLUTION: A gas meter has a gas inflow path 6 formed inside an upper case 3 from an inlet port 4 formed to be exposed above a top wall of the upper case 3 of a gas meter body, and a valve seat 9 of an emergency shut-off valve, formed in the vicinity of a near-bottom portion of a side wall 6a of the gas inflow path 6 such that a part of an arc thereof overlaps with the side wall 6a of the gas inflow path 6, where a bottom surface 6b of the gas inflow path 6 is located at a level lower than the valve seat 9. Such an arrangement suppresses flow resistance and vortex flow of gas, thereby reducing pressure loss in the gas inflow path.SELECTED DRAWING: Figure 3

Description

In the present invention, a measuring chamber is formed in a lower case of a gas meter main body formed of a die-cast body, and an inlet side base and an outlet side base are exposed on the upper surface of the top wall of the upper case formed on the lower case. Further, the present invention relates to a so-called membrane gas meter in the upper case, in which an emergency shut-off valve that shuts off the gas flow (metering) in an emergency is installed in the gas inlet-side flow path. The present invention relates to a membrane gas meter in which a gas flow port formed between valve seats of an emergency shut-off valve is enlarged to reduce gas flow resistance (pressure loss) as much as possible.

In the case of a conventional membrane gas meter, the demand for downsizing is required, so the gas inflow path entering the machine room from the inlet base through the valve seat of the gas emergency shutoff valve in the upper case is narrow. It is formed in space.

For this reason, there is a problem in that the flow path shape is unreasonable, and particularly when the flow rate is large, the pressure loss increases.

In addition, the lower case and the upper case of the membrane gas meter main body are die-cast molding methods, so that a punching die is used in various places for molding the gas inflow path, and the thickness direction is vertical and horizontal. For this reason, there are problems that not only the flow path has many right-angled parts, but also the formation of the flow path becomes unreasonable depending on the direction in which the mold is pulled out, and the pressure loss as a whole is inevitably increased.

For example, FIG. 4 shows a cross-section of a conventional upper case. In the case of this gas inflow path, the flow of gas a flowing into the upper case 3 from the inlet side cap 4 is the gas from the inlet side cap 4. After flowing down the inflow path 6 of the gas, it hits the bottom surface 6b, changes its direction by 90 °, and flows to the valve seat 9 side of the emergency shutoff valve. Therefore, the flow port 12 of the gas flowing by turning 90 ° from the gas inflow path 6 toward the valve seat 9 is about 45 ° as shown in FIGS. 4 and 6. Since the divergence angle (circular arc) is about, the flow resistance at the flow port 12 is large, which is a major cause of the pressure loss.

Further, since the gas directly collides with the bottom surface 6b of the gas inflow path 6 and changes its direction by 45 ° and flows into the valve seat 9, an eddy current is generated in the gas flow by the impact at this time, The gas flow became unstable when passing through, and this was also a major cause of pressure loss.

An object of the present invention is to provide a membrane gas meter in which the pressure loss that causes gas flow resistance is reduced as much as possible in the flow of gas from the inlet side cap through the valve seat of the emergency shutoff valve.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a membrane gas meter, wherein a gas inflow path is formed from an inlet-side base formed on the top wall of the upper case of the gas meter body toward the upper case. In the membrane gas meter in which the emergency shutoff valve and the valve seat are formed in a direction perpendicular to the gas inflow path, a part of an arc is formed on a part of the side wall of the inlet gas inflow path. Thus, the gas that flows directly from the gas inflow path to the valve seat side is formed by forming the valve seat and setting the position of the bottom surface of the inlet gas inflow path below the position of the valve seat. The flow port is expanded to reduce the pressure loss in the portion that passes through the valve seat from the gas inflow path.

The invention according to claim 2 is the membrane gas meter according to claim 1, wherein the position of the valve seat is set on or near the center line of the inlet-side gas inflow passage. Is.

In the present invention, since the gas flowing in from the inlet side cap descends in the gas inflow passage, the emergency shut-off valve valve seat is formed so that a part of the arc is applied to the side wall of the gas inflow passage. The flow port for the gas flowing to the sheet side can be maximized.

As a result, there is almost no shape part that obstructs the flow of gas while passing through the valve seat from the gas inflow path, and the gas flows into the valve seat in a shape close to straight, so the influence of pressure loss is ignored. This is particularly effective when measuring large flow rates.

It is a front view of the film | membrane type gas meter main body which implemented this invention. It is A-A 'line sectional drawing. It is explanatory drawing of the Example which concerns on this invention which formed the valve seat so that a part of circular arc might be applied to the side wall of the gas inflow path. It is explanatory drawing of the prior art example which formed the valve seat so that a part of circular arc might cover the bottom face of the inflow path of gas. It is explanatory drawing of the positional relationship of the inflow path of gas which concerns on this invention, and a valve seat. It is explanatory drawing of the positional relationship of the gas inflow path and valve seat which concerns on a prior art example.

The present invention is a flow meter for measuring the flow rate of a gas, and is a so-called meter that drives a metering membrane by gas pressure and mechanically measures the flow rate from the pulsating motion of the metering membrane to measure gas consumption. The present invention can be applied to both a mechanical type and a so-called electronic gas meter that measures a gas flow rate by detecting a pulsating motion with an electronic sensor.

That is, in the case of both types of gas meters, the gas flowing in from the inlet side cap has the same configuration from the emergency shutoff valve to the measuring chamber (measuring membrane). Is characterized in that the pressure loss is reduced as much as possible in the flow path configuration between the valve seats of the emergency shutoff valve.

FIG. 1 is a front view of a membrane gas meter. Reference numeral 1 denotes a gas meter body, 2 denotes a lower case in which a measuring chamber is incorporated, and 3 is formed on the lower case 2. As shown in FIGS. 2 and 3, the gas that has flowed in from the inlet base 4 descends via the gas inflow passage 6 and is part of the arc of the valve seat 9. Is configured to flow directly into the valve seat 9 of the emergency shut-off valve 8 from the flow port 11 formed so as to cover the side wall 6a of the gas inflow path 6.

Reference numeral 5 denotes an outlet side cap, and a taper 7a is formed in the discharge channel 7 of the outlet side cap 5 to eliminate the step 13 which is a cause of pressure loss as shown in the conventional example (FIG. 4). Yes.

The relationship between the inlet side cap 4 and the gas inflow path 6 will be described in more detail. A part of the arc of the valve seat 9 is partly on the side wall 6 a of the gas inflow path 6. A flow port 11 is formed large between 6a and the valve seat 9.

In this configuration, according to the present invention, in the side wall 6a of the gas inflow path 6 formed downward following the inlet side cap 4, the valve seat 9 of the emergency shutoff valve 8 has a part of the arc of the gas inflow path. 6, the flow port 11 is formed on the side wall 6a, so that the flow port 11 shown in FIG. 5 has a size of about 2 when compared with the flow port 12 of FIG. Magnified 5 times.

As a result, the gas flowing in from the inlet side cap 4 descends the gas inflow path 6 and flows directly into the valve seat 9.

Further, by positioning the bottom surface 6b of the gas inflow path 6 below the position of the valve seat 9, the gas flow that has flowed in does not directly collide with the bottom surface 6b and change its direction, thereby suppressing the generation of vortex flow. As a result, the pressure loss was greatly reduced.

The position of the valve seat 9 is substantially the same as the center line of the gas inlet side inflow passage 6 as shown in FIG. 2, but this position may be slightly back and forth with respect to the center line. There is no great difference in the size of the flow port 11, and therefore, it is not particular about matching with the center line. However, if it is not matched, a position that slightly shifts to the downstream side of the gas flow is preferable.

In FIG. 2, 8a is a valve portion of the emergency shut-off valve 8, 8b is an attachment port of the emergency shut-off valve 8 formed on the upper case side, and 10 is a reset button.

Incidentally, in the case of the present invention shown in FIG. 5, the pressure loss was 23.50 Pa, but in the case of the flow port 12 of FIG. 6 which is the conventional example, the pressure loss was 52.29 Pa.

DESCRIPTION OF SYMBOLS 1 Gas meter main body 2 Lower case 3 Upper case 4 Inlet side cap 5 Outlet side cap 6 Gas inflow path 6a Side wall 6b of gas inflow path 7 Bottom surface of gas inflow path 7 Gas discharge path 8 Emergency shutoff valve 8a Emergency shutoff valve Valve portion 8b mounting port 9 valve seat 10 reset button 11 flow port 12 of the present invention flow port of conventional example

Claims (2)

An inflow path of gas is formed from the inlet base formed on the top wall of the upper case of the gas meter main body into the upper case, and an emergency shut-off valve is directed in a direction perpendicular to the inflow path of the gas. In the membrane gas meter in which the valve seat is formed, the valve seat is formed so that a part of the arc is applied to a part of the side wall of the inlet gas inflow passage, and the bottom surface of the inlet gas inflow passage Is set lower than the position of the valve seat, thereby expanding the flow port of the gas flowing directly from the gas inflow path to the valve seat side, and the pressure loss of the portion passing through the valve seat from the gas inflow path Membrane gas meter with reduced pressure. 2. The membrane gas meter according to claim 1, wherein the position of the valve seat is set on or near the center line of the inlet side gas inflow passage.

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