JP2002372444A - Flow rate measuring pressure detector and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure detector for measuring the flow rate and its manufacturing method which accurately detects the pressure and can be manufactured at a low cost. SOLUTION: The method of manufacturing a flow rate measuring pressure detector for measuring the flow rate, based on the pressure difference between pipes at the upstream and downstream of an orifice plate 5 inserted in pipings 1, 3 forms a plurality of pressure pickup holes 7a-7b, 14a-14b distant with specified spacings in the circumferential direction of the pipings 1, 3 located at the upstream and downstream of the orifice plate 5, connects T-shaped pressure guide pipes 9, 16 directly or through bosses 8, 15 to the pressure pickup holes 7a-7d, 14a-14d, mutually couples the pressure guide pipes through arcuate or bend-like pipes 10a-10d, 17a-17d to form rings 11, 18 and connects inner spaces 11a, 18a of the rings to a flow meter 13 through single pressure guide pipes 12, 19, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detecting device for measuring a flow rate of a low pressure gas piping such as a fuel gas of a blast furnace and a method of manufacturing the same.

[0002]

2. Description of the Related Art In general, as a device for measuring the flow rate of a fluid flowing in a pipe, a pressure detecting device provided with an orifice plate and detecting a differential pressure before and after the orifice plate is well known. For example, as shown in FIG. 6, a single hole or a slit 101a,
Annular chamber 102a, 1 for extracting pressure via 1b
02b is provided, and a pressure tapping tube 103a, 103b is connected to this portion, or a predetermined distance is provided between the upstream side and the downstream side of the orifice plate (for example, 1D (D
Is the inner diameter of the pipe) and the downstream side is 0.5D), and there is a DD / 2 tap (contracting tap) type in which a single pressure outlet is provided.

[0003] In a low pressure gas piping such as a fuel gas of a blast furnace, the pressure inside the piping is not good because the diameter of the piping is large and the gas flows at a low pressure. For this reason, conventionally, a D · D / 2 tap (contracting tap) in which a single pressure outlet is provided upstream and downstream of the orifice plate.
Since accurate pressure detection cannot be expected in the system, the corner tap system is exclusively used.

[0004]

However, in the above-mentioned corner tap type, the annular chamber 102a,
In addition to the fact that the member constituting 102b is manufactured by machining from a forged material, the diameter of the pipe is large and large, so that there is a problem that the cost required for the manufacture is considerable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a pressure measuring device for flow measurement which can perform accurate pressure detection and can be manufactured at low cost, and a method of manufacturing the same. .

[0006]

According to the present invention, there is provided a pressure detecting device for measuring a flow rate, which measures a flow rate by a pressure difference between a pipe located above and downstream of an orifice plate provided in the middle of a pipe. In the pressure measuring device for measuring flow rate, a plurality of pressure outlets are formed at predetermined intervals in a circumferential direction of a pipe positioned on the upstream side and the downstream side of the orifice plate, and these pressure outlets are formed. Is formed around the pipe by an annular chamber forming member made of a pipe material, and the pressure in the annular chamber is transmitted to the flow meter by one pressure guiding pipe.

Further, the annular chamber forming member is a ring connected to the pressure outlet through a pressure guiding tube.

Further, the annular chamber forming member is a half-split pipe joined to the outer peripheral surface of the pipe so as to directly communicate with the pressure outlet.

Further, a method of manufacturing a flow rate measuring pressure detecting device according to the present invention is directed to a flow rate measuring pressure detecting apparatus for measuring a flow rate based on a pressure difference in a pipe above and downstream of an orifice plate interposed in the middle of a pipe. A method for manufacturing a detection device, comprising forming a plurality of pressure outlets at predetermined intervals in a circumferential direction of a pipe located on an upstream side and a downstream side of the orifice plate, and directly or bossing the pressure outlet. A T-shaped impulse line is connected indirectly via a pipe, and the impulse lines are connected to each other with an arc-shaped or bent tubular pipe to form a ring, and the inner space of the ring is connected to the flow meter with one impulse line. It is characterized in that each is connected.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a flow rate measuring pressure detecting device according to the present invention;

[First Embodiment] FIG. 1 shows a first embodiment of the present invention, and is a side view of a low-pressure gas piping provided with a flow rate measuring pressure detecting device, and FIG. 2 is a line II-II in FIG. FIG. 3 is a view taken along line III-III in FIG.

As shown, a tube 1 having a predetermined inner diameter D
Pipe 3 having a predetermined inner diameter D as in the case of the joining flange 2 of FIG.
Are connected to each other by a plurality of bolts and nuts 6 equally spaced in the circumferential direction with the orifice plates 5 sandwiched therebetween.

Four pressure outlets 7a to 7d are formed at a predetermined distance (for example, 1D) away from the orifice plate 5 of the tube 1 at a predetermined distance (for example, 1D) in the circumferential direction and spaced apart by a predetermined distance in the circumferential direction. . T-shaped pressure guide pipes (branch pipes) 9 are respectively connected to the pressure outlets 7a to 7d via bosses 8, and arc-shaped pipes 10a to 10d are provided between the pressure guide pipes 9.
Are joined to form a ring (annular chamber forming member) 11. The internal space (annular chamber) 11 a of the ring 11 communicates with the flow meter 13 via one pressure guiding tube 12.

[0014] In addition, four pressure outlets 1 spaced apart from each other by a predetermined distance (for example, 0.5 D) at a predetermined distance (for example, 0.5 D) from the orifice plate 5 of the pipe 3 in the circumferential direction.
4a to 14d are formed. These pressure outlets 14a
T-shaped pressure guide pipes (branch pipes) 16 are respectively connected to the pipes 14 to 14d via bosses 15, and arcuate pipes 17a to 17d are connected between the pressure guide pipes 16 to form a ring (annular chamber forming member). 18 are configured. The internal space (annular chamber) 18 a of the ring 18 communicates with the flow meter 13 via one pressure guiding tube 19.

The boss 8 (15) is connected to the tube 1 (3).
Of the T-shaped pressure guiding tube 9 (16) is welded to the boss 8 (15) in a state where the base end of the T-shaped pressure guiding tube 9 (16) is overlapped with the boss 8 (15) by a predetermined length. Are joined. The arc-shaped pipes 10a to 10d (17
a to 17d) are respectively welded at both ends thereof to the ends of the T-shaped pressure guiding tube 9 (16).

With this configuration, when detecting the pressure around the orifice plate 5 in the tubes 1 and 3,
The internal pressure is taken out from different parts by four pressure guiding tubes 9 and 16 arranged at predetermined intervals in the circumferential direction, and is introduced into the internal spaces 11 a and 18 a of the rings 11 and 18.

At this time, if the pressure balance in the pipes 1 and 3 is poor, different pressures will be taken out by the four pressure guiding pipes 9 and 16, respectively. 18 are uniformed in the internal spaces 11a and 18a. This uniform pressure is one impulse line 1
Since they are transmitted to the flow meter 13 by 2 and 19 respectively,
The pressure can be accurately detected, and the flow rate of the low-pressure gas flowing through the pipes 1 and 3 can be measured with high accuracy by the differential pressure across the orifice plate 5.

In the present embodiment, since the above-described pressure detecting device is almost entirely made of a pipe material, the members constituting the annular chambers 102a and 102b (see FIG. 6) are made of forged material as described above. As compared with the corner tap type manufactured by the shaving process, the simplification of the structure and the simplification of the manufacturing can greatly reduce the cost.

[Second Embodiment] FIG. 4 is a front sectional view of a low-pressure gas pipe having a flow rate measuring pressure detecting device according to a second embodiment of the present invention.

This is the same as the pipe 10a in the first embodiment.
This is an example in which the shapes of the rings 11 and 18 are changed from circular to octagonal instead of arcuate ones to 10d and 17a to 17d.

According to this, there is an advantage that the pipes 10a to 10d and 17a to 17d are more easily formed in the bent tube than in the arcuate one. Other configurations and actions
The effects are the same as in the first embodiment.

[Third Embodiment] FIG. 5 is a side sectional view of a main part of a low-pressure gas piping showing a third embodiment of the present invention.

This is because the ring 11, 11 in the first embodiment
18 instead of a half-split pipe (annular chamber forming member) 2
0 is directly joined to the outer peripheral surfaces of the pipes 1 and 3 by welding so that the pressures taken out from the pressure outlets 7a to 7d and 14a to 14d are made uniform in the internal space (annular chamber) 20a of the pipe 20. It is an example.

According to this, the bosses 8, 15 and T-shaped pressure guiding tubes (branch tubes) 9, 16 in the first and second embodiments become unnecessary, and the cost can be further reduced by reducing the number of parts. There is an advantage that it can be achieved. Other configurations, operations, and effects are the same as those of the first embodiment.

The present invention is not limited to the above embodiments,
It goes without saying that various changes such as a change in the cross-sectional shape of the pipe can be made without departing from the gist of the present invention.

[0026]

As described above in detail with reference to the embodiments, the invention according to claim 1 of the present invention is characterized in that the flow rate is determined by the pressure difference between the pipes above and below the orifice plate interposed in the middle of the pipe. In the pressure detecting device for measuring flow rate, a plurality of pressure outlets are formed at predetermined intervals in the circumferential direction of the pipe located on the upstream side and the downstream side of the orifice plate, and these pressure outlets are formed. An annular chamber communicating with the mouth is formed around the pipe by an annular chamber forming member made of a pipe material, and the pressure in the annular chamber is transmitted to the flow meter by one pressure guiding pipe. While accurate pressure detection can be performed by absorbing the pressure balance difference in the inside, most of the pressure detection device is made of pipe material, so the members that make up the annular chamber are manufactured by machining from forged material Be done Compared with those of Natappu system,
Significant cost reductions can be achieved by simplifying the structure and facilitating manufacture.

The invention according to a second aspect of the present invention is characterized in that the annular chamber forming member is a ring connected to the pressure outlet through a pressure guiding tube, respectively. In addition to the functions and effects of the invention, there is an advantage that assembly of the pipe material is easy.

The invention according to a third aspect of the present invention is characterized in that the annular chamber forming member is a half-split pipe joined to the outer peripheral surface of the pipe so as to directly communicate with the pressure outlet. Therefore, in addition to the operation and effect of the invention according to claim 1, there is an advantage that the cost can be further reduced by reducing the number of parts.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a flow rate measuring pressure detecting device for measuring a flow rate based on a pressure difference between a pipe located above and downstream of an orifice plate interposed in the middle of a pipe. A plurality of pressure outlets are formed at predetermined intervals in the circumferential direction of the pipe located on the upstream side and the downstream side of the orifice plate, and the pressure outlets are formed directly or indirectly through bosses. The pressure-guiding pipes are connected in a U-shape, and the pressure-guiding pipes are connected to each other with an arcuate or bent pipe to form a ring, and the internal space of the ring is connected to the flow meter with a single pressure-guiding pipe. Therefore, the same operation and effect as those of the first aspect can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a low-pressure gas system pipe provided with a flow rate measuring pressure detecting device according to a first embodiment of the present invention.

FIG. 2 is a view taken along the line II-II of FIG.

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

FIG. 4 is a front cross-sectional view of a low-pressure gas system pipe provided with a flow rate measuring pressure detecting device according to a second embodiment of the present invention.

FIG. 5 is a side sectional view of a main part of a low-pressure gas piping showing a third embodiment of the present invention.

FIG. 6 is a structural explanatory view of a conventional corner tap type pressure detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 2 Joining flange part 3 Pipe 4 Joining flange part 5 Orifice plate 6 Bolt-nut 7a-7d Pressure outlet 8 Boss 9 Pressure guiding tube (branch tube) 10a-10d Pipe 11 Ring (annular chamber forming member) 11a Internal space ( Annular chamber) 12 Pressure guiding tube 13 Flow meter 14a to 14d Pressure outlet 15 Boss 16 Pressure guiding tube (branch tube) 17a to 17d Pipe 18 Ring (annular chamber forming member) 18a Internal space (annular chamber) 19 Pressure guiding tube 20 Pipe (annular) Chamber forming member) 20a Internal space (annular chamber)

Claims (4)

[Claims] 1. A flow rate measuring pressure detecting device for measuring a flow rate based on a pressure difference in a pipe above and below an orifice plate interposed in the middle of a pipe, wherein the flow rate measuring device is located upstream and downstream of the orifice plate. A plurality of pressure outlets are formed at predetermined intervals in the circumferential direction of the pipe, and an annular chamber communicating with these pressure outlets is formed around the pipe by an annular chamber forming member made of pipe material, and A pressure measuring device for flow measurement, wherein the pressure in the annular chamber is transmitted to the flow meter by one pressure guiding tube. 2. The flow rate measuring pressure detecting device according to claim 1, wherein the annular chamber forming member is a ring connected to each of the pressure outlets via a pressure guiding tube. 3. The flow rate measuring device according to claim 1, wherein the annular chamber forming member is a half-split pipe joined to an outer peripheral surface of a pipe so as to directly communicate with the pressure outlet. Pressure detector. 4. A method of manufacturing a pressure measuring device for measuring a flow rate, wherein a flow rate is measured by a pressure difference in a pipe above and below an orifice plate interposed in the middle of a pipe, the method comprising: A plurality of pressure outlets are formed at predetermined intervals in the circumferential direction of the pipe located on the downstream side, and a T-shaped pressure guiding tube is connected to the pressure outlet directly or indirectly via a boss, A ring is formed by connecting the pressure guiding tubes with an arc-shaped or bent pipe, and the internal space of the ring is connected to a flow meter by a single pressure guiding tube. Production method.