JPH11212656A - Pressure governing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flow of gas to secondary side piping without installing a slum shut valve on a main pipe even when a pilot regulation pipe is broken. SOLUTION: A first pilot governor 12 and a needle valve 11 are successively provided for connection through a main governor 3 and further through a pilot regulation pipe 10 so as to open a valve with the reduction of pressure to detect primary side piping 1 and secondary side piping 2, a pressure detecting part 12a of the first pilot governor 12 is connected to the downstream side of the needle valve 11, and a pressure detecting part 3a of the main governor 3 is connected to the middle of the first pilot governor 12 and the needle valve 11. Concerning such a pressure governing mechanism, in this case, a second pilot governor 16 to close the valve with the reduction of detected pressure is provided in the middle of the first pilot governor 12 and the needle valve 11 and its pressure detecting part 16a is connected to the downstream side of the needle valve 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure regulating mechanism in which a primary side pipe and a secondary side pipe are connected via a main governor for flowing a fluid while adjusting a fluid pressure. It is used for a supply pipe for gas and the like.

[0002]

2. Description of the Related Art Conventionally, as a pressure regulating mechanism of this kind, FIG.
As shown in FIG. 1, the primary pipe 1 and the secondary pipe 2 are connected via a main governor 3 that allows the fluid to flow while adjusting the fluid pressure, and the primary pipe 1 and the secondary pipe 2 are connected to each other. In order to connect with the pilot adjustment pipe 10, a first pilot governor 12 and a throttle valve 11, which are opened by a decrease in pressure to be detected, are sequentially provided in the pilot adjustment pipe 10, and a pressure detection unit 12a of the first pilot governor 12 is provided. Is connected to the downstream side of the throttle valve 11 of the pilot adjustment pipe 10 via a first pilot governor adjustment pipe 15, and the main governor 3 closes due to a decrease in the detected pressure.
Is connected between the first pilot governor 12 and the throttle valve 11 of the pilot adjusting pipe 10 via the main governor adjusting pipe 14. Although a normally closed governor is used for the main governor 3, it is highly safe to close the valve when the loading pressure is reduced due to leakage of fluid or the like.

[0003] The connecting portion of the pilot adjusting pipe 10 with the secondary pipe 2 needs to be guided from the straight pipe, and is usually buried in the ground. In some cases, the adjustment tube may be damaged.

[0004]

SUMMARY OF THE INVENTION Pilot adjusting pipe 10
When the connection side with the secondary pipe 2 is damaged, the pressure detected via the adjustment pipe 10 decreases, the pilot governor 12 opens, and the flow rate to the downstream side increases. Since the throttle valve 11 is provided in the downstream pilot adjustment pipe 10, an increase in the flow rate causes an increase in the pressure, and an increase in the pressure detected via the main governor adjustment pipe 14 causes the main governor 3 to open. When the valve is opened, the pressure in the secondary pipe 2 rises, and gas leaks from a damaged portion of the adjusting pipe 10, so that it is impossible to prevent the gas from flowing to the secondary pipe 2.

To solve this problem, it is conceivable to provide a slam shut valve, which is an emergency shut-off valve for preventing pressure rise, upstream of the main governor 3. However, in this case, the following problem arises. That is, the primary pipe 1, which is the main pipe, has a large diameter compared to the pilot adjustment pipe 10, so that the slam shut valve itself becomes expensive, and it is difficult to newly provide a slam shut valve in the existing pipe. The construction is very large.

Accordingly, it is an object of the present invention to provide a highly safe control system in which the main governor can prevent gas flow to the secondary pipe even if the pilot adjustment pipe is broken without installing a slam shut valve in the main pipe. It is to provide a pressure mechanism.

[0007]

To achieve the above object, the present invention is characterized in that a primary pipe and a secondary pipe are connected to each other.
Connecting the primary pipe and the secondary pipe with a pilot adjustment pipe while connecting via a main governor that allows the fluid to flow while adjusting the fluid pressure, a drop in the pressure to be detected is detected in the pilot adjustment pipe. A first pilot governor and a throttle valve, which are opened by the valve, are sequentially provided, and a pressure detecting section of the first pilot governor is connected to a downstream side of the throttle valve of the pilot adjusting pipe, and the main governor detects a pressure to be detected. And a pressure detecting unit connected between the first pilot governor and the throttle valve of the pilot adjustment pipe. A second pilot governor, which is closed between the pilot governor and the throttle valve due to a decrease in detected pressure, is provided, and the pressure detecting unit is connected to the pilot regulator. There in that is connected downstream of the throttle valve of the tube. The operation and effect are as follows.

[Effects] According to the features of the present invention,
As described above, if the connection part of the pilot adjustment pipe with the secondary pipe is broken, the pressure detected through the adjustment pipe will decrease, the pilot governor will open, and the flow rate to the downstream side will increase. Trying to make the first
A second pilot governor, which is closed between the pilot governor and the throttle valve due to a decrease in the detected pressure, is provided, and the pressure detector is connected to the downstream side of the throttle valve of the pilot adjustment pipe. As a result, the second pilot governor closes due to a decrease in the pressure detected by the pressure detector. Since the gas on the downstream side of the second pilot governor escapes from the throttle valve, the pressure detected through the main governor adjusting pipe is reduced, the main governor is closed, and the gas flows to the secondary pipe. Can be prevented. In other words, compared to providing a slam shut valve on the main pipe, the same function can be achieved simply by adding a small pilot governor, and installation on the pilot adjustment pipe is also easy, Due to the small size, the problem of installation space hardly occurs. Normally, the second pilot governor is
Because the valve is opened by the pressure guide from the pilot adjustment pipe,
The pressure regulation function can be maintained. As a result, without installing a slam shut valve in the main pipe, it is possible to provide a highly safe pressure regulating mechanism that can prevent gas flow to the secondary pipe by the main governor even if the pilot adjustment pipe is broken. did it.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a main governor 3 is provided at a connection portion between the primary pipe 1 and the secondary pipe 2, whereby the primary pipe 1 is connected to the secondary pipe while adjusting the fluid pressure. The fluid is passed to 2. The target fluid is, for example, city gas (hereinafter simply referred to as gas) g, and the secondary pipe 2
Downstream is a city gas demand area. And, in response to the demand for gas, the gas flows to the downstream side and flows out in the secondary side pipe 2, and when the gas is not supplied from the primary side,
A pressure drop occurs on the secondary side.

The primary side pipe 1 and the secondary side pipe 2 are connected by a pilot adjusting pipe 10.
, A first pilot governor 12, a second pilot governor 16, and a throttle valve 11 are sequentially provided. The first pilot governor 12 is a normally open diaphragm-type direct acting governor that opens when the pressure detected by the pressure detecting unit 12a decreases. The pressure detection unit 12a
The pilot adjustment pipe 10 is connected to the downstream side of the throttle valve 11 via the pilot governor adjustment pipe 15, and when the pressure detected there decreases, the valve body 12b is spring-biased in the opening direction to open. The second pilot governor 16 is a normally-closed diaphragm-type direct acting governor that closes when the pressure detected by the pressure detector 16a decreases. The pressure detector 16a is provided with a second pilot governor adjusting pipe 17
Is connected to the downstream side of the throttle valve 11 of the pilot adjustment pipe 10, and when the pressure detected there is reduced, the valve body 16 b is spring-biased in the closing direction to close the valve. Throttle valve 11
As long as it has a function of restricting the flow rate from the upstream side to a predetermined amount, a variable flow rate valve can be used.

The main governor 3 is a normally-closed diaphragm-type linear motion governor. When the pressure detected by the pressure detector 3a decreases, the valve body 3b is biased by a spring in the closing direction to close the valve. The pressure detection unit 3a is connected to the throttle valve 11 of the pilot adjustment pipe 10 through the main governor adjustment pipe 14 and the second valve.
It is connected to the middle of the pilot governor 16 and can guide the pressure from the pilot adjustment pipe 10 to the pressure detecting unit 3a.

The connection side of the pilot adjustment pipe 10 with the secondary pipe 2 is buried in the ground.

Next, the operation of the pressure regulating mechanism will be described. Normally, the secondary pipe 2 flows downstream in response to gas demand, and when the gas supply from the primary side is insufficient, a pressure drop occurs on the secondary side, which is caused by the pilot adjustment pipe. The pressure is guided to the pressure detector 12 a of the pilot governor 12 via the first governor 10 and the first pilot governor adjusting pipe 15.
When the valve element 12b is spring-biased in the opening direction and opens due to a decrease in the pressure detected by the pressure detecting unit 12a, the flow of the pilot governor 12 is increased by the opening of the pilot governor 12, and the throttle valve 11 is opened. Since the pressure is present, the pressure is increased, and the pressure is guided to the pressure detection unit 3a of the main governor 3 through the main governor adjusting pipe 14. As a result, the valve body 3b is spring-biased in the opening direction due to an increase in the pressure detected by the pressure detecting unit 3a, the main governor 3 is opened, and the pressure drop on the secondary side recovers to regulate the pressure. Function works. On the other hand, when the pilot adjustment pipe 10 in the soil is damaged, the adjustment pipe 10 and the first pilot governor adjustment pipe 1 are damaged.
5, the first pilot governor 12 opens, and the flow rate to the downstream side of the first governor 12 tends to increase, but due to the damage, the first pilot governor 12 passes through the second pilot governor adjusting pipe 17 through the second pilot governor adjusting pipe 17. The second pilot governor 16 closes due to a decrease in the pressure detected by the pressure detector 16a. Then, since the gas downstream of the second pilot governor 16 escapes from the throttle valve 11, the pressure detected through the main governor adjusting pipe 14 is reduced, the main governor 3 is closed, and the gas is supplied to the secondary side pipe 2. Can be prevented from flowing.

[Another Embodiment] Another embodiment of the present invention will be described below. (B) In the above embodiment, an example in which a normally-closed diaphragm-type linear motion governor is used as the main governor and the second pilot governor has been described. Various types can be used.

(B) In the above embodiment, an example is shown in which a normally open diaphragm type linear motion governor is used as the first pilot governor. Various types can be used.

(C) In the above embodiment, the example in which the gas flowing through the pipe is city gas (gas) is shown. However, this may be any fluid as long as it is a fluid. Name.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a pressure regulating mechanism of the present invention.

FIG. 2 is a schematic view showing an example of a conventional pressure regulating mechanism.

[Description of Signs] 1 Primary pipe 2 Secondary pipe 3 Main governor 3a Pressure detector 10 Pilot adjustment pipe 11 Throttle valve 12 First pilot governor 14 Main governor adjustment pipe 16 Second pilot governor 16a Pressure detector g Fluid

Claims (1)

[Claims] 1. A primary side pipe and a secondary side pipe are connected via a main governor for flowing a fluid while adjusting a fluid pressure, and a pilot adjustment pipe is connected between the primary side pipe and the secondary side pipe. The pilot adjustment pipe is provided with a first pilot governor and a throttle valve, which are opened in response to a decrease in the pressure to be detected, in the pilot adjustment pipe, and a pressure detection unit of the first pilot governor is connected to the throttle of the pilot adjustment pipe. The main governor is connected to a downstream side of the valve, and the main governor closes due to a decrease in detected pressure, and a pressure detecting unit is connected to an intermediate portion of the pilot adjustment pipe between the first pilot governor and the throttle valve. A pressure regulating mechanism, wherein a second pilot governor that closes due to a decrease in pressure to be detected is provided between the first pilot governor and the throttle valve of the pilot adjustment pipe. And a pressure regulating mechanism having a pressure detector connected downstream of the throttle valve of the pilot adjustment pipe.