JPH06314128A - Pressure governor - Google Patents

Abstract

PURPOSE:To improve an offset at the time of a large flow rate without spoiling hunting performance. CONSTITUTION:A governor body 14 is interposed between a primary-side duct 11 and a secondary-side duct 12. An operation part 14a is controlled with the pressure in an intermediate pressure duct 13. A restrictor 15 is interposed between the intermediate pressure duct 13 and the primary-side duct 11. A pilot valve 16 is interposed between the intermediate pressure duct 13 and the secondary-side duct 12. The flow rate of the secondary-side duct 12 is detected by a flow rate detector 25. A diaphragm 26 is displaced to the right when the flow rate increases to displace a connecting shaft 24 to the right. The tip of the connecting shaft 24 is coupled with a link lever 21 through a link pin 23 and a valve body 17 is angularly displaced to increase the restriction quantity, thereby making air hard to flow through the duct 11a. Consequently, the pressure drop across the restrictor 15 increases to improve the offset of secondary pressure P2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure regulator used in a gas supply line such as a governor used to control the supply pressure of city gas.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 62-120.
As disclosed in Japanese Patent No. 517, a plurality of governors are provided in the city gas supply system. The governor reduces the primary pressure when the city gas is supplied from the upstream side to the secondary pressure, which is a lower pressure, and supplies it to the downstream side. Even if the flow rate of city gas supplied to the downstream side fluctuates,
The purpose of using the governor is to prevent the secondary pressure from fluctuating.

FIG. 7 shows a schematic configuration of a typical prior art governor. A governor 3 is interposed between the primary side pipeline 1 and the secondary side pipeline 2. The governor 3 includes a governor body 4, a restrictor 5, and a pilot valve 6.
The restrictor 5 is a conduit 1 a that branches from the primary conduit 1.
And the pipe line 4a communicating with the inside of the governor body 4. The pilot valve 6 is interposed between the pipeline 4a and the pipeline 2a communicating with the secondary side pipeline 2. A valve body 7 formed of a rubber film is provided on the bottom of the governor body 4. The central portion of the valve body 7 is the inlet 1 which is the tip of the primary side conduit 1.
b, the peripheral portion of the valve body 7 faces the outlet 2b, which is the tip of the secondary conduit 2, via the cage 8. The cage 8 is formed by a perforated plate. Examples of the governor body 4, the restrictor 5 and the pilot valve 6 are, for example, TYPE 399 manufactured by Fisher Controls Co., Ltd.
A 12 restrictor and a 161Y pilot valve are preferably used.

The governor 3 as shown in FIG. 7 keeps the secondary pressure P2 constant, for example, at a gauge pressure of 200 mmAq as follows. Here, the secondary pressure P2 is 200 mm
When it is Aq, it is assumed that the pilot valve 6 is closed. Since the inside of the governor body 4 communicates with the primary side pipe line 1 via the restrictor 5 which is a throttle, the pressure PR
Is equal to the primary pressure P1. Since P1 = PR in this way, PR> P2, and the valve body 7 hits the cage 8 to seal it.

When the secondary pressure P2 decreases from 200 mmAq to 190 mmAq, for example, the pilot valve 6
Opens. As a result, the gas in the governor body 4 is discharged to the conduit 2a.
Escape to the secondary conduit 2 via. The pressure PR in the governor body 4 is the primary pressure P corresponding to the pressure decrease by the restrictor 5.
It becomes smaller than 1. When the pressure PR in the governor body 4 becomes small, the valve body 7 is lifted by the primary pressure P1,
Gas flows from the inlet 1b through the cage 8 to the outlet 2b. As a result, the secondary pressure P2 rises and the secondary pressure is kept constant.

[0006]

Although a pressure regulator such as the governor 3 shown in FIG. 7 is provided to keep the secondary pressure P2 constant regardless of the flow rate, as shown in FIG. The secondary pressure P2 decreases in the region where the flow rate Q increases. A phenomenon in which the secondary pressure P2 decreases in such a large flow rate region is called offset. If the throttle amount of the restrictor 5 is increased, the amount of gas supplied into the governor body 4 is decreased, so the pressure PR is decreased, the valve body 7 is deformed, and the gas in the inlet 1b moves into the outlet 2b. It will be easier. As a result, the inclination angle α is reduced and the offset of the secondary pressure P2 is reduced. However, since the restrictor 5 greatly reduces the amount of gas flowing through the restrictor 5, the response speed of the valve body 7 in the closing direction of the valve PR of the pressure PR in the governor body 4 becomes slow, which is called hunting to the secondary pressure P2. A fluctuation phenomenon is likely to occur. As described above, if the offset is to be suppressed, the hunting performance is sacrificed in the small flow rate range, and it is difficult to achieve both the offset suppression and the hunting suppression.

An object of the present invention is to provide a pressure regulator which can improve the offset in the large flow rate range without sacrificing the hunting performance in the small flow rate range.

[0008]

SUMMARY OF THE INVENTION In the present invention, a pressure regulator main body is interposed in a gas supply pipe line to reduce an upstream primary pressure to a downstream secondary pressure, and to provide a primary pressure and a secondary pressure. In the pressure regulator that adjusts the opening of the valve by using the intermediate pressure between the two, and keeps the secondary pressure constant regardless of the flow rate of the gas to be supplied, it is interposed between the intermediate pressure pipe line and the downstream side, A pilot valve that conducts at a pressure equal to or higher than a set pressure, a detection unit that detects the flow rate of gas, and a pipe line on the upstream side and a pipe line at an intermediate pressure are provided. And a restrictor that expands the flow passage cross-sectional area when the flow rate is small and reduces the flow passage cross-sectional area when the flow rate is large.

[0009]

According to the present invention, the pressure regulator is used to reduce the primary pressure on the upstream side to the secondary pressure on the downstream side to keep the secondary pressure constant regardless of the flow rate of the gas supplied. The opening degree of the valve of the pressure regulator main body is adjusted by using the intermediate pressure between the primary pressure and the secondary pressure.

A pilot valve is interposed between the intermediate pressure pipe and the downstream side. The pilot valve becomes conductive when the difference between the intermediate pressure and the secondary pressure becomes equal to or higher than the set pressure. A throttle is interposed between the upstream pipeline and the intermediate pressure pipeline. In response to the detection output of the flow rate of the gas detected by the detecting means, the throttle increases the flow passage cross-sectional area when the flow rate on the downstream side where hunting is likely to occur is small, and maintains good hunting characteristics. When the flow rate of gas is large, the flow path cross-sectional area is reduced,
Improve the offset.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of an embodiment of the present invention. The governor 10 includes a primary side pipeline 11 and a secondary side pipeline 12.
Is intervened between. The governor 10 operates the operating portion 14 a of the governor body 14 by the pressure of the gas in the intermediate pressure line 13.
Is controlled to reduce the primary pressure P1 to the secondary pressure P2,
And the secondary pressure P2 is kept constant. The structure of the governor body 14 is similar to that of the prior art shown in FIG. 7, for example. A conduit 11a branches from the primary-side conduit 11, and is connected to the intermediate pressure conduit 13 via a restrictor 15 which is a throttle. A pilot valve 16 and a conduit 12a are interposed between the intermediate pressure conduit 13 and the secondary conduit 12. The throttle amount of the restrictor 15 can be changed by angularly displacing the valve body 17.

The upper portion of the valve body 17 is fixed to one end of the link lever 21 by a nut 22. The link lever 21 is substantially linear. The other end of the link lever 21 is connected to the connecting shaft 24 via a link pin 23.

The connecting shaft 24 penetrates the flow rate detector 25. The inside of the flow rate detector 25 is partitioned into two spaces by a diaphragm 26. Stop pieces 27 and 28 are provided in the middle and the tip of the connecting shaft 24, respectively. An adjusting spring 29 is provided between the intermediate stop piece 27 and the housing of the flow rate detector 25.
Is provided. The adjusting spring 29 presses the stop piece 27 to bring it into contact with the stopper 31 when the pressure difference between both surfaces of the diaphragm 26 in the flow rate detector 25 is small.
At this time, the stop piece 28 at the tip of the connecting shaft 24 is fixed to the stopper 3
It is located away from 2.

Gases from pressure detection tubes 33 and 34 are introduced to both sides of the diaphragm 26 of the flow rate detector 25, respectively. The tip 33a of the pressure detection pipe 33 opens near the axis of the secondary side pipe line 12 toward the upstream side. The tip 34a of the pressure detection tube 34 opens near the outlet 12b at the tip of the secondary side conduit 12. The radius of the vicinity of the outlet 12b is smaller than that of the secondary side pipeline 12 on the downstream side, and the gas flow velocity increases in inverse proportion to the cross-sectional area. Therefore, the secondary conduit 12
When the flow velocity of the gas in the inside increases, the pressure in the pressure detecting pipe 33 increases and the pressure in the pressure detecting pipe 34 decreases. As a result, the diaphragm 26 moves to the right side in FIG. 1, the stop piece 27 moves away from the stopper 31, and the stop piece 28 moves to the right side until it hits the stopper 32. When the connecting shaft 24 is displaced to the right, the link lever 21 is moved through the link pin 23.
Is angularly displaced in the clockwise direction, and the valve body 17 is angularly displaced so that the throttle amount increases.

FIG. 2 shows operating characteristics of the pressure regulator 10 shown in FIG. Until the flow rate Q reaches Qa, the stop piece 27 remains in contact with the stopper 31, and the restrictor 1
The aperture amount of 5 is small. The set pressure of the pilot spring 19 at this time is set to such an extent that hunting can be suppressed by the throttle amount of the restrictor 15. The inclination β1 of the secondary pressure P2 at this time becomes larger than the inclination angle α shown in FIG. When the flow rate becomes Qa, the pressure detection tubes 33, 3
The pressure difference between the four shafts increases, and the connecting shaft 24 starts to displace to the right in FIG. The spring 29 contracts, and the lever 21 is angularly displaced in the clockwise direction to increase the throttle amount of the restrictor 15. While the flow rate is between Qa and Qb, the connecting shaft 24 is displaced against the adjusting spring 29, so that the secondary pressure P shown in FIG.
2 rises at an angle of β2 with the horizontal axis. When the flow rate Qb is reached, the stop piece 28 at the tip of the connecting shaft 24 contacts the stopper 32, and the connecting shaft 24 is no longer displaced to the right side in FIG. Therefore, the secondary pressure P2 shown in FIG. 2 drops again at an angle β3 with the horizontal axis. As described above, the secondary side pipeline 1
When the flow rate Q in 2 increases, the valve body 17 of the restrictor 15 is angularly displaced so as to increase the throttle amount via the link mechanism, and therefore, as in the section of flow rates Qa to Qb shown in FIG. A section in which the secondary pressure P2 rises rather is formed, and an increase in offset can be prevented even if the flow rate Q increases. The flow rate detector 25 detects the flow rate from the difference between the pressure of the gas in the central portion of the secondary side pipeline 12 and the pressure corresponding to the flow velocity of the gas near the outlet 12b, but either one of them is detected. Of course, the flow rate may be detected from only the flow rate.

FIG. 3 shows a schematic structure of another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 1, and the corresponding parts are designated by the same reference numerals. It should be noted that the flow rate detected by the flow rate detector 35 is electrically processed to control the electrically controlled restrictor 36. For this control, a control device 37 including a microcomputer and the like is provided. From the flow rate detector 35, a signal indicating the flow rate detected via the flow rate detection line 38 is given to the control device 37. Controller 37
From which a signal for controlling the restrictor 36 is derived via the restrictor control line 39.

FIG. 4 is a schematic exploded perspective view of the restrictor 15, and FIG. 5 is a sectional view thereof. The restrictor 15 is
It is composed of a cylindrical valve body 17 and a rectangular parallelepiped valve box 40. The valve body 17 is provided with a notch 17a, and the valve box 4
It is accommodated in a recess 40a provided at 0 for angular displacement.
The valve box 40 has a through hole 4 perpendicular to the axial direction of the valve body 17.
0b and 40c are provided. By using the valve element 17 and the valve box 40 as described above, the flow passage cross-sectional area can be adjusted as shown in FIGS. 5 (A) and 5 (B).

FIG. 6 shows a schematic structure of still another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 1, and the corresponding parts are designated by the same reference numerals. It should be noted that the diaphragm support 43 and the adjusting spring 47 are provided in the governor body 41, and the primary pressure P1 and the governor body 4 are provided.
The deformation of the valve element 42 due to the pressure difference from the pressure PR in 1 is transmitted to the connecting shaft 44 via the diaphragm support 43, and the valve element 45 provided at the upper end of the connecting shaft 44 is displaced to move the restrictor 46. It is to adjust the aperture amount. The restrictor 46 is partitioned into two spaces by a partition plate 48. The partition plate 48 is provided with a hole 49 serving as a valve seat. The operation of the valve body 42 is similar to that of the valve body 7 shown in FIG. 7. Clearances are provided between the valve body 42 and the diaphragm support 43, and between the upper end of the shaft of the diaphragm support 43 and the plate 50 provided at the lower end of the connecting shaft 44. A stopper 51 is provided in the middle of the connecting shaft 44. A valve element 45 is provided on the upper end of the connecting shaft 44. An adjusting spring 52 is provided between the stopper 51 and the housing of the restrictor 46. The restricting amount of the restrictor 46 can be changed by increasing or decreasing the opening area of the hole 49 depending on the displacement amount of the valve body 45. Further, the change characteristic of the aperture amount can be adjusted by changing each clearance.

In each of the above embodiments, the governor in the city gas supply system has been described, but it is needless to say that the secondary pressure can be effectively controlled even if it is used in another gas supply system. is there.

[0020]

As described above, according to the present invention, the flow passage cross-sectional area of the throttle is adjusted according to the gas flow rate. When the flow rate is low, the flow path cross-sectional area is enlarged, and when the flow rate is high, the flow path cross-sectional area is reduced. This improves the hunting characteristics in the small flow rate region and improves the offset in the large flow rate region. In this way, it is possible to obtain the pressure regulator in which the fluctuation of the pressure on the secondary side is suppressed.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a graph showing the operation of the embodiment shown in FIG.

FIG. 3 is a piping system diagram showing a schematic configuration of another embodiment of the present invention.

FIG. 4 is an exploded perspective view of a diaphragm 15 shown in FIG.

5 is a schematic cross-sectional view showing an operating state of the diaphragm 15 shown in FIG.

FIG. 6 is a piping system diagram showing a schematic configuration of another embodiment of the present invention.

FIG. 7 is a piping system diagram showing a schematic configuration of a prior art.

FIG. 8 is a graph showing the operation of the prior art shown in FIG. 7.

[Explanation of symbols]

 10 governor 11 primary side conduit 12 secondary side conduit 13 intermediate pressure conduit 14,41 governor body 15,36,46 restrictor 16 pilot valve 17,42,45 valve body 21 link lever 22 link pin 24,44 connecting shaft 25, 35 Flow rate detector 26 Diaphragm 27, 28 Stop piece 29, 47, 52 Adjustment spring 31, 32, 51 Stopper 33, 34 Pressure detection pipe 37 Control device 43 Diaphragm support 48 Partition plate

Front page continued (72) Inventor Ryuichi Nakamura 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture Osaka Gas Co., Ltd. (72) Inventor Shigeru Fukui 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. Osaka Gas Co., Ltd. (72) Inventor Kiyoshi Murata No. 4-1-2 Hiranocho, Chuo-ku, Osaka City, Osaka Prefecture Osaka Gas Co., Ltd.

Claims (1)

[Claims] 1. A pressure regulator body is interposed in a gas supply line,
The upstream side primary pressure is reduced to the downstream side secondary pressure, and the valve opening is adjusted using the intermediate pressure between the primary pressure and the secondary pressure, regardless of the flow rate of the supplied gas. In a pressure regulator that keeps the secondary pressure constant, a pilot valve that is interposed between the intermediate pressure line and the downstream side and that conducts at a set pressure or higher, a detection unit that detects the gas flow rate, and an upstream side line. A diaphragm that is interposed between the pipe and an intermediate-pressure pipe and responds to the detection output from the detection means to expand the flow passage cross-sectional area when the gas flow rate is small and reduce the flow passage cross-sectional area when the gas flow rate is large. A pressure regulator comprising: and.