JPH0669748U - Flowmeter - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a flowmeter configured to eliminate a lead wire mounted between a case and a measurement unit. [Structure] In the case 1, a measurement unit 2 for measuring the flow rate of city gas and a flow rate display unit 3 are housed. The measurement unit 2 is a fluid vibration type measurement unit that vibrates a fluid by using a fluidic element, and is mounted and fixed on the inner wall 1 a of the bottom plate of the case 1. Front 1 of case 1
An operation member 29 is provided at b, and a reset switch 31 is provided at the measurement unit 2 housed in the case 1. The operation member 29 closely faces the reset switch 31, and when pressed, turns the reset switch 31 on.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a flow meter, and more particularly to improvement of a flow meter in which a switch is provided on the front surface of a case.

[0002]

[Prior art]

 Each home has a flow meter that measures the amount of city gas used. A flow meter of this type is, for example, a turbine type flow meter that detects the rotation of a turbine rotating at a rotation speed according to the flow rate of gas, or a fluid vibration type flow meter that vibrates a fluid using a fluidic element. Have been developed.

In a conventional flow meter, a measurement unit for measuring the flow rate and a flow rate display section are housed in a box-shaped case, and an upstream side connecting section and a downstream side connecting section to which an upstream side piping is connected at the bottom of the case. And a downstream side connecting portion to which is connected. The flow rate indicator is fixed on the upper part of the measuring unit, and it is mounted and fixed on the inner wall of the bottom plate of the case. Further, the case is provided with a reset switch for returning the shutoff valve which is operated after the shutoff valve provided in the measurement unit main body is closed.

The reset switch is attached to the front surface of the case and is connected to an electric circuit on a board provided in the measurement unit via a lead wire. Therefore, when the reset switch is pressed and turned on, the electric circuit stops the passage of electricity to the solenoid of the shutoff valve, and the shutoff valve opens. As a result, the gas supply to the downstream side is restarted and the flow rate can be measured by the flow meter.

[0005]

[Problems to be solved by the device]

 However, in the above flow meter, since the reset switch provided on the front surface of the case and the electric circuit on the board provided on the measurement unit are connected by the lead wire, for example, during the assembly process or the maintenance after the installation, the measurement unit is Since the lead wire is an obstacle when it is separated from the case, it is necessary to take care not to cut the lead wire at the time of assembly or disassembly, so that there is a problem that assembly work and maintenance work are troublesome.

Therefore, an object of the present invention is to provide a flow meter that solves the above problems.

[0007]

[Means for Solving the Problems]

 The present invention relates to a flowmeter in which a measuring unit for measuring a flow rate is housed in a box-shaped case, and a switch is provided on the front surface of the case. An operation member is displaceably provided on the front surface of the case. It is characterized in that the switch is provided in the measuring unit facing the operation member so as to be switched by displacement of the member.

[0008]

[Action]

 According to the present invention, the operation member for operating the switch is provided on the front surface of the case, and the switch is provided on the measurement unit, so that the lead wire mounted between the case and the measurement unit is unnecessary, and the case and the measurement unit are eliminated. Assembly work and maintenance work with can be done easily.

[0009]

【Example】

 1 to 3 show an embodiment of a flow meter according to the present invention.

In each of the drawings, a box-shaped case 1 accommodates a measuring unit 2 for measuring the flow rate of city gas, and a flow rate display section 3, and the case 1 has an upstream side to which an upstream side pipe is connected. A connection part 4 and a downstream side connection part 5 to which the downstream side pipe is connected are provided. The measurement unit 2 is a fluid vibration type measurement unit that vibrates a fluid using a fluidic element to measure the flow rate, as described later, and has a flow rate display section 3 fixed to the upper part thereof. The measurement unit body 2a is screwed on the inner wall 1a of the bottom plate of the case 1 so that the flow rate display unit 3 attached to the upper portion of the measurement unit 2 faces the display window 7 of the case 1 without tilting with respect to the display window 7. Fixed by 9. Then, the back cover 8 is attached to the back surface 1c of the case 1 and fixed by the screw 10.

Here, the configuration of the measuring unit 2 will be described.

As shown in FIG. 1, the measuring unit 2 flows into the inflow passage 11 communicating with the upstream side connecting portion 4 and in an emergency (for example, when gas pressure is increased or when an abnormality such as an earthquake occurs). A shutoff valve 12 that shuts off the passage 11, a pressure switch 13 that turns on when the inflow passage 11 reaches a preset pressure value and outputs a detection signal thereof, and a rectifying net 14 provided in the inflow passage 11 And the flow rate measuring unit 15. The flow rate measuring unit 15 includes a jet nozzle 16, a columnar target 17, first to fourth guide members 18 to 21, a flow velocity sensor 27 that measures the flow velocity of the gas passing through the jet nozzle 16, and a vibration of the jet flow. It has a piezoelectric film sensor 28 for detecting a pressure fluctuation associated with the operation.

The measurement unit main body 2 a is provided with an inflow chamber 22 that communicates with the inflow passage 11 and an oscillation chamber 23 that communicates with the downstream side connecting portion 5. A jet nozzle 16 is provided between the inflow chamber 22 and the oscillation chamber 23. Therefore, the fluid (in this embodiment, city gas) flowing into the inflow chamber 22 from the inflow passage 11 is accelerated by the ejection nozzle 16 to become the jet A and ejected to the oscillation chamber 23, which is caused by the columnar target 17 and the Coanda effect. It oscillates due to the action of the return flows B and C and flows out from the outlet 24.

When the jet A oscillates in the left-right direction, the position where the jet A passes is a left-hand flow D directed between the guide members 18 and 21 as fluid adhering walls and a fluid-attached portion as shown by a broken line in FIG. There is a rightward flow E toward the space between the guide members 19 and 21 as the landing wall.

That is, the jet flow A from the jet nozzle 16 is deflected leftward or rightward in FIG. 1 to be the return flow B or the return flow C by the action of the columnar target 17 and the Coanda effect. The return flow B switches the direction of the jet A to the right, and the return flow C switches the direction of the jet A to the left. The vibration frequency of the jet A is proportional to the flow rate regardless of the physical properties of the fluid.

Pressure introducing holes 25 and 26 are formed below the flows D and E through which the jet flow A passes. The pressure introduced through the pressure introducing holes 25 and 26 is directly detected by the piezoelectric film sensor 28, and the vibration frequency is obtained from the output of the piezoelectric film sensor 28. The measurement unit 32 provided on the measurement unit 2 at the rear of the flow rate display unit 3 obtains the vibration frequency of the jet flow from the detection signal from the piezoelectric film sensor 28, and calculates the flow rate based on this. Further, a circuit board (not shown) of the measuring unit 32 is provided with an arithmetic circuit for calculating the flow rate and a reset switch for returning the shutoff valve described later.

An operation member mounting portion 30 is provided on the front surface 1b of the case 1. An operating member 29 for returning the shutoff valve, which is operated after the shutoff valve 12 is closed, is displaceably attached to the operating member attachment portion 30. The operation member mounting portion 30 has a support hole 30a at the center thereof for supporting the operation member 29 so that the operation member 29 can be displaced in the axial direction. A first annular recess 30b for preventing rainwater from entering is provided outside the support hole 30a, and an annular projection 30c protruding axially is provided on the outside thereof. A second annular recess 30d for holding the operating member 29 is provided outside the annular protrusion 30c. Further, an annular stepped portion 30e that restricts the axial displacement of the operating member 29 is provided outside the second annular recess 30d.

The first annular concave portion 30b and the second annular concave portion 30d are formed in groove shapes that become deep in the axial direction so that rainwater does not easily enter. Further, the inner wall of the second annular recess 30d is formed in a tapered shape, and the inlet side of the second annular recess 30d has a small diameter, and the inner diameter becomes larger toward the inner part.

Reference numeral 31 denotes a reset switch for returning the shutoff valve, which is provided on the substrate (not shown) of the measuring unit 32 described above. The reset switch 31 is a push switch which is turned on when the rod 31a is pressed in the X direction and is turned off when the pressing is released. The rod 31a is a push switch of the operation member mounting portion 30 of the case 1. It projects forward so as to face the support hole 30a.

The operation member 29 is made of a material having a relatively soft elasticity, such as rubber, and has a pressing portion 29a having a gentle curved surface on one surface, as shown in FIG. A round bar-shaped operation guide portion 29b protruding in the axial direction is provided at the center of the other surface. Further, an annular recess 29c is provided outside the operation guide portion 29b, and a cylindrical protrusion 29d that axially protrudes outside thereof. Further, a switch contact portion 29e which also functions as a slip-out prevention portion is provided at the tip of the operation guide portion 29b. A flange portion 29f that fits into the annular step portion 30e is provided on the peripheral portion of the operating member 29.

The operation guide portion 29b has a smaller diameter than the support hole 30a, and the switch contact portion 29e has a larger diameter than the operation guide portion 29b and the support hole 30a. The outer peripheral shape of the switch contact portion 29e is tapered so that the tip end becomes thin, and when the operation member 29 is attached, as will be described later, insertion into the support hole 30a becomes easy.

The operation member 29 is attached to the operation member attachment portion 30 by applying the switch contact portion 29e to the support hole 30a and pressing the switch contact portion 29e in the X direction. At this time, the switch contact portion 29e penetrates the support hole 30a, the operation guide portion 29b is inserted into the support hole 30a, and the cylindrical protrusion 29d is fitted in the second annular recess 30d. Then, the operating member 29 is pressed in the X direction until the collar portion 29f comes into contact with the annular step portion 30e, and the attachment is completed.

The cylindrical projection 29d is tapered in diameter while the tip portion thereof is in sliding contact with the second annular recess 30d. Therefore, the cylindrical protruding portion 29d has a waterproof structure in which the cylindrical protruding portion 29d is in close contact with the second annular recessed portion 30d to seal the gap with the second annular recessed portion 30d and prevent rainwater from entering. Further, the annular concave portion 29c is attached so as to be displaceable in the axial direction (X direction) without coming into contact with the annular protruding portion 30c. Therefore, when the pressing portion 29a is pressed in the X direction, the collar portion 29f is in contact with the annular step portion 30e, so that the central portion is largely bent in the same direction, and the operation guide portion 29b and the switch contact portion 29e are supported by the support holes. It is displaced in the X direction while being guided by 30a.

As described above, when the measurement unit 2 is housed in the case 1 in which the operation member 29 is attached to the operation member attachment portion 30, the switch contact portion 29e of the operation member 29 is provided in the measurement unit 2. The reset switch 31 closely faces the rod 31a. Therefore, there is no lead wire between the reset switch 31 and the operating member 29, and they are separated by a slight gap S. Therefore, it is not necessary to take care not to cut the lead wire when the measuring unit 2 is mounted in the case 1 or when the measuring unit 2 is taken out from the case 1, and the assembling work or the maintenance work becomes easy, and the efficiency is improved. Can work well.

After the flow meter having the above-described structure is installed in the gas supply pipe (not shown) to each home, for example, when the earthquake or the gas pressure rises abnormally, the shut-off valve 12 is closed. The flow path 11 may be blocked. Then, when the abnormality is resolved and the gas supply is restarted, the reset switch 31 is turned on.

That is, as shown in FIG. 5, when the pressing portion 29a of the operating member 29 is pressed in the X direction, the central portion of the pressing portion 29a, the operation guide portion 29b, and the switch contact portion 29e are guided by the support hole 30a. Move in the X direction. Therefore, the switch contact portion 29e presses the rod 31a of the reset switch 31 in the same direction, and the reset switch 31 is turned on. As a result, the shutoff valve 12 is deenergized and opened, and the gas supply is resumed.

Since the operating member 29 is made of rubber having a relatively soft elasticity, the operating force is small, and when the pressing finger is separated from the pressing portion 29a after the pressing operation is completed, the pressing portion 29a is pressed. The elastic restoring force of the cylindrical protrusion 29d restores the state shown in FIG.

Further, rainwater may be sprayed onto the front surface 1b of the case 1, but even in that case, the cylindrical projection 29d of the operating member 29 is expanded by the tapered inner wall of the second annular recess 30d and comes into close contact therewith. Therefore, rainwater is prevented from entering the inside of the operation member mounting portion 30. Furthermore, when water leakage occurs between the cylindrical protrusion 29d and the second annular recess 30d, the annular protrusion 30c and the first annular protrusion 30c that axially protrude inside the second annular recess 30d. Since the recess 30b is provided, rainwater is prevented from entering the support hole 30a.

In the above embodiment, the fluid vibration type measurement unit that vibrates the fluid by using the fluidic element is described as being housed in the case. However, the present invention is not limited to this. Of course, it can also be applied to other types of flow meters such as meter and roots type flow meter.

Further, in the above embodiment, the flow meter for measuring city gas has been described as an example, but the present invention is not limited to this, and other fluids (for example, propane gas, liquefied natural gas or liquids such as gasoline, light oil, kerosene, etc.) can be used. ) Is also applicable to the flow meter.

Further, in the above embodiment, the configuration in which the operating member 29 for operating the reset switch 31 for shutting off the valve is provided on the front surface 1b of the case 1 has been described as an example, but the present invention is not limited to this, and other switches. An operation member for operating the may be provided on the front surface 1b of the case 1.

In the above embodiment, the rubber operation member 29 is provided on the front surface 1b of the case 1. However, the invention is not limited to this. For example, a synthetic resin operation button may be attached so as to be slidable in the front-rear direction. It may be configured.

[0033]

[Effect of device]

 As described above, the flowmeter according to the present invention does not require a lead wire mounted between the case and the measurement unit by providing the operation unit for operating the switch on the front surface of the case and providing the switch on the measurement unit. Therefore, the assembling work and the maintenance work of the case and the measurement unit can be easily performed, and the assembling work and the maintenance work can be efficiently performed in a short time. In addition, the breakage of the lead wire mounted between the case and the measurement unit does not occur, so reliability during assembly work and maintenance work is improved, and defects due to breakage of the lead wire can be eliminated. With the features of.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view showing an embodiment of a flow meter according to the present invention.

FIG. 2 is a vertical sectional view of the flow meter taken along the line AA in FIG.

FIG. 3 is a transverse cross-sectional view showing the attachment structure of the operating member taken along the line BB in FIG.

FIG. 4 is a partial cutaway view showing a configuration of a measurement unit.

FIG. 5 is a cross-sectional view showing an operation state of a reset switch and an operation member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 case 2 measurement unit 2a measurement unit main body 3 flow rate display unit 16 ejection nozzle 17 columnar target 18-21 first to fourth guide members 29 operation member 30 operation member mounting portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidenori Wakabayashi 1-3-6 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa Tokiko Corporation (72) Hideaki Ikeda 1-3-6 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa No. Tokiko Co., Ltd. (72) Inventor Tatsuro Kuromaru 1-6-3 Fujimi, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Tokiko Co., Ltd. (72) Shigenori Okamura 3-95, Chiyosaki, Nishi-ku, Osaka Osaka Prefecture Gas Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A flowmeter comprising a box-shaped case, a measuring unit for measuring a flow rate, and a switch provided on the front surface of the case. A flowmeter, wherein the switch is provided in the measurement unit facing the operation member so that the switch is switched according to the displacement of the operation member.