JP2016095065A - Combustible gas supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a fast detection of a leakage at a cutoff valve used for cutting off combustible gas and restrict an amount of combustible gas flowing into a demand location even if gas leakages occur at each of the double cutoff valves.SOLUTION: A combustible gas supply device 1 including a first cutoff valve 11 and a second cutoff valve 12 arranged in series against a combustible gas supply pipe 10 comprises an inert gas supply pipe 20 for supplying inert gas between the first cutoff valve 11 and the second cutoff valve 12; a pressure adjuster valve 21 arranged at the inert gas supply pipe 20; pressure detection means 22 for detecting a pressure in the pipes in a region A enclosed by the first cutoff valve 11, the second cutoff valve 12 and the pressure adjuster valve 21; flow rate detection means 23 arranged at the inert gas supply pipe 20; and control means 30 for controlling a degree of opening of the pressure adjustor valve 21 in such a way that the inert gas is supplied under the second pressure higher than the first pressure that is pressure of the combustible gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas supply device that supplies, blocks, or holds a combustible gas using a double shutoff valve.

  Conventionally, in a steel mill, for example, blast furnace gas (BFG) or coke oven gas (COG), which is a combustible gas, is obtained as a by-product gas from a blast furnace or a coke oven. These combustible gases are supplied to a combustion facility such as a boiler or a coke oven, and used as fuel.

  The flammable gas supply piping that supplies these flammable gases to customers such as combustion facilities is provided with a shut-off valve that shuts off the supply of the flammable gas, but in the unlikely event that a gas leaks from the shut-off valve In such a case, there is a risk of causing a serious event such as a fire, explosion, or gas poisoning at the customer site. For this reason, there may be a case where two shutoff valves are provided in series in the combustible gas supply pipe, assuming that gas leaks from the shutoff valve in the event of a particularly severe shutoff.

  In addition, for example, when the demand destination is a combustion facility, if a gas leak occurs from the shut-off valve, the combustion furnace of the combustion facility is filled with combustible gas, and the burner for gas combustion is ignited in that state. There is also a risk of explosion. Therefore, in the shutoff valve that shuts off these flammable gases, a so-called leak check is performed to confirm the presence or absence of a leak.

  For example, Patent Document 1 proposes a device for performing a leak check of a double shutoff valve in which shutoff valves are provided in series. The device of Patent Document 1 has means for displacing the pressure between the shutoff valves provided in double (in series) and means for detecting the pressure between the shutoff valves. Then, after closing the double shut-off valve, the pressure between the double shut-off valves is set to a predetermined pressure value, and there is a leak when the detected pressure value falls below the specified value within a predetermined time. Judge.

JP-A-2-180392

  However, in the apparatus of Patent Document 1, it is necessary to wait until a predetermined time elapses in order to detect a leak even if a leak has actually occurred in the shut-off valve. In other words, the leakage of the shut-off valve could not be detected immediately.

  In addition, if a gas leak occurs in both the upstream and downstream shutoff valves of the double shutoff valve provided in series, the combustible gas passes through each shutoff valve and the combustible gas flows out to the customer. There is also the problem of continuing.

  The present invention has been made in view of such a point, and even when a leak of a shutoff valve used for shutting off a flammable gas is detected quickly and a gas leak occurs in each shutoff valve of the double shutoff valve. The purpose is to minimize the amount of combustible gas flowing into customers.

  To achieve the above object, the present invention provides a combustible gas supply apparatus having a first shutoff valve and a second shutoff valve provided in series with a combustible gas supply pipe for supplying a combustible gas. An inert gas supply pipe for supplying an inert gas between the first shut-off valve and the second shut-off valve in the combustible gas supply pipe, and the inert gas supply pipe. A pressure control valve that controls the pressure of an inert gas supplied to the gas supply pipe; and a combustible gas supply pipe or an inert gas surrounded by the first shut-off valve, the second shut-off valve, and the pressure control valve Pressure detecting means for detecting the pressure inside at least one of the supply pipes, flow rate detecting means for detecting the flow rate of the inert gas flowing through the inert gas supply pipe, the first shut-off valve, and the second shut-off valve When the shut-off valve is closed, the pressure of the combustible gas Control means for controlling the opening of the pressure control valve based on a pressure detection value of the pressure detection means so as to supply the inert gas at a second pressure higher than the first pressure. It is characterized by having.

  According to the present invention, when the first shut-off valve and the second shut-off valve are closed, the inert gas is supplied at a second pressure higher than the first pressure that is the pressure of the combustible gas. The control means for controlling the opening degree of the pressure control valve based on the pressure detection value of the pressure detection means. Therefore, when a leak occurs in at least one of the first shut-off valve and the second shut-off valve and the pressure detection value of the pressure detecting means decreases, the pressure control valve is used to compensate for this pressure drop. An inert gas is supplied. Then, since the flow rate is detected by the flow rate detection means provided in the inert gas supply pipe, when the flow rate detection value by the flow rate detection means exceeds a predetermined threshold value, the first cutoff valve or the second cutoff valve It can be immediately determined that at least one of the leaks has occurred. Therefore, the time required for determining the leakage of the shut-off valve can be greatly shortened as compared with the conventional case.

  Further, for example, even when leakage occurs in both the first shut-off valve and the second shut-off valve, the second pressure higher than the first pressure that is the pressure of the combustible gas by the pressure control valve. By supplying inert gas under pressure, the flow of combustible gas between the first shut-off valve and the second shut-off valve is shut off by the inert gas, and the flow rate of combustible gas flowing to the customer is minimized. To the limit.

  When the flow rate detection unit detects a flow rate exceeding a predetermined threshold after the pressure detection unit detects the arrival of the second pressure, the control unit detects the first cutoff valve or the second cutoff valve. It may be determined that at least one of the leaks has occurred.

  The first shut-off valve is provided on the upstream side of the second shut-off valve, and is located upstream of the first shut-off valve in the combustible gas supply pipe or the second shut-off valve in the combustible gas supply pipe. Other pressure detection means for detecting the pressure inside the combustible gas supply pipe may be further provided at least on the downstream side of the shutoff valve.

  The first shut-off valve and the second shut-off valve are floating ball valves, and the first shut-off valve and the second shut-off valve are connected from the inert gas supply pipe to the combustible gas supply pipe. On the other hand, when the inert gas is supplied at a pressure higher than that of the combustible gas, the valve body of the first shut-off valve and the valve body of the second shut-off valve are pressed against the secondary side seat, respectively. May be arranged.

  Quickly detect the leakage of the shutoff valve used to shut off the combustible gas, and minimize the amount of combustible gas flowing into the customer even if both of the shutoff valves of the double shutoff valve leak gas. Can be suppressed.

It is a systematic diagram which shows the outline | summary of a structure of the combustible gas supply apparatus concerning this Embodiment. It is a time chart which shows the operation state of each apparatus of a combustible gas supply apparatus. It is a systematic diagram which shows the outline | summary of a structure of the combustible gas supply apparatus concerning other embodiment.

  Embodiments of the present invention will be described below. FIG. 1 is a system diagram showing an outline of the configuration of the combustible gas supply device 1 according to the present embodiment. In the present embodiment, a case where coke oven gas, which is a byproduct gas from a coke oven, stored in the gas holder 2, for example, is supplied to the catalyst reformer 3, for example, will be described as an example.

  The combustible gas supply device 1 includes, for example, a combustible gas supply pipe 10 that supplies coke oven gas stored in the gas holder 2 to the catalyst reformer 3, and an upstream side (gas holder 2 side) of the combustible gas supply pipe 10 The first shut-off valve 11 and the second shut-off valve 12 are provided in series in this order on the downstream side (catalyst reformer 3 side). The first cutoff valve 11 and the second cutoff valve 12 constitute a double cutoff valve. As the first cutoff valve 11 and the second cutoff valve 12, for example, a floating ball valve is used. The first shut-off valve 11 is configured such that when the pressure on the catalyst reforming device 3 side of the first shut-off valve 11 is higher than the pressure on the gas holder 2 side, the valve body of the ball valve It arrange | positions so that it may press on the sheet | seat of a secondary side. As for the second shut-off valve 12, when the pressure on the gas holder 2 side becomes higher than the pressure on the catalyst reforming device 3, the valve body of the ball valve is pressed against the secondary side seat of the ball valve. Is arranged.

  Between the first shutoff valve 11 and the second shutoff valve 12 in the combustible gas supply pipe 10, an inert gas is supplied to the combustible gas supply pipe 10 from an inert gas supply source (not shown). An active gas supply pipe 20 is connected at the junction Q. As the inert gas, it is preferable to use, for example, nitrogen or the like, but any gas can be used as long as it does not have auxiliary combustion properties.

  The inert gas supply pipe 20 is provided with a pressure control valve 21 that controls the pressure of the inert gas supplied to the combustible gas supply pipe 10. The inert gas supply pipe 20 is provided with pressure detection means 22 for detecting the pressure inside the inert gas supply pipe 20.

  Note that the pressure detection means 22 has at least one of the combustible gas supply pipe 10 and the inert gas supply pipe 20 in the region A surrounded by the first cutoff valve 11, the second cutoff valve 12, and the pressure control valve 21. It is only necessary to detect the internal pressure. Therefore, the installation position of the pressure detection means 22 is not limited to the inert gas supply pipe 20 and may be installed between the first cutoff valve 11 and the second cutoff valve 12 in the combustible gas supply pipe 10. The arrangement of the pressure control valve 21 is a position as close as possible to the confluence point Q in order to improve the responsiveness of the pressure change (change in the pressure detection value of the pressure detection means 22) with respect to the change in the opening degree of the pressure control valve 21. It is preferable to provide in.

  On the upstream side of the pressure control valve 21 in the inert gas supply pipe 20, a flow rate detecting means 23 for detecting the flow rate of the inert gas flowing through the inert gas supply pipe 20 is provided. The flow rate detection means 23 may be provided on the downstream side of the pressure control valve 21. If the flow rate of the inert gas passing through the pressure control valve 21 can be accurately measured, the flow rate detection means 23 is optional in the inert gas supply pipe 20. It can be installed at the position. Further, the inert gas supply pipe 20 is provided with a check valve 24 for preventing the backflow of the combustible gas from the combustible gas supply pipe 10 to the inert gas supply pipe 20 as necessary.

  The combustible gas supply device 1 is provided with a control means 30, for example, the detection results of the pressure detection means 22 and the flow rate detection means 23, and the open / close state of the first cutoff valve 11 and the second cutoff valve 12. A signal such as a limit switch (not shown) is detected. The control means 30 outputs a signal for operating the pressure control valve 21, the first cutoff valve 11, the second cutoff valve 12 and the like based on these input signals.

  The combustible gas supply apparatus 1 concerning this Embodiment is comprised as mentioned above. Next, a specific operation of the combustible gas supply device 1 according to the present embodiment will be described.

In supplying the combustible gas from the gas holder 2 to the catalyst reformer 3, the second cutoff valve 12 and the first cutoff valve 11 are opened. Thus combustible gas, the combustible gas feed pipe 10 toward the gas holder 2 to the catalytic reformer 3, for example, is supplied at a first pressure P _1. At this time, the pressure control valve 21 is fully closed. The control means 30 may be provided with an interlock that prevents the pressure control valve 21 from being opened unless the first cutoff valve 11 and the second cutoff valve 12 are fully closed.

  When shutting off the combustible gas, first, the second shutoff valve 12 and the first shutoff valve 11 are closed. Thereby, in the combustible gas supply pipe 10 and the inert gas supply pipe 20, the region A surrounded by the first cutoff valve 11, the second cutoff valve 12, and the pressure control valve 21 is the first cutoff valve 11. If there is no leakage in the second shut-off valve 12, it is in a sealed state.

  After the first shut-off valve 11 and the second shut-off valve 12 are fully closed, for example, a leak check for confirming the presence or absence of leak from the first shut-off valve 11 and the second shut-off valve 12 by the control means 30 Is done. This leak check will be described with reference to the time chart shown in FIG.

In the leak check, first, automatic control of the pressure control valve 21 is started by the control means 30 so that the pressure detection value of the pressure detection means 22 reaches a predetermined pressure (time T _{0 in} FIG. 2). At this time, the predetermined pressure as the control set value of the pressure control valve 21 is set to a _second pressure P ₂ higher than P ₁ that is the supply pressure of the combustible gas. As a result, the inert gas is supplied from the inert gas supply pipe 20 to the combustible gas supply pipe 10, the pressure in the region A reaches the second pressure P ₂ (time T _{1 in} FIG. 2), and thereafter It is maintained in the second pressure P _2. The first pressure P ₁ and the amount of pressure difference between the second pressure P _2, for example, considering the accuracy of the pressure detection means 22, for example, be a pressure of the inert gas for some reason is or hunting it is preferable that the pressure detection value by the pressure detector 22 is set to a value enough not first pressure P ₁ follows. However, if the pressure difference becomes excessively large, in other words, if the supply pressure of the inert gas is excessive, for example, it is considered that the device power on the side of the inert gas supply source (not shown) increases. The pressure difference is preferably set appropriately in consideration of these viewpoints.

When the pressure detection value of the pressure detecting means 22 reaches the second pressure P _2, then the pressure regulating valve 21 as indicated by the solid line in FIG. 2 is fully closed, thereby the pressure in the region A second pressure P ₂ is maintained. At the same time, the control means 30 determines whether there is leakage from the first cutoff valve 11 and the second cutoff valve 12. A method for determining the presence or absence of leakage from the first cutoff valve 11 and the second cutoff valve 12 by the control means 30 will be specifically described.

For example, the first shut-off valve 11, if no leakage occurs in the second shut-off valve 12, after the pressure detection value of the pressure detecting means 22 has reached the second pressure P ₂ (time T ₁ after the Figure 2) The pressure control valve 21 is fully closed, and the inert gas does not flow through the inert gas supply pipe 20. In this case, the flow rate detection value of the flow rate detection means 23 is zero as shown by the solid line in FIG.

However, the first shut-off valve 11, when at least leak in one of the second shut-off valve 12 is occurring, a second pressure P ₂ is the pressure of the region A is the supply pressure of the combustible gas 1 higher than the pressure P ₁ in the regions gas in a passes through the first shut-off valve 11 and the second shut-off valve 12, the upstream side of the tube of the first shut-off valve 11 in the flammable gas supply pipe 10 It leaks out to the line 10a and the pipe line 10b on the downstream side of the second shut-off valve 12. In such a case, the pressure in the area A, that the pressure detection value of the pressure detecting means 22, for example, as shown by the broken line in FIG. 2, decreases toward the first pressure P _1. Then, in order to restore the pressure in the region A to the second pressure P ₂ that is the control set value, the pressure adjusting valve 21 is opened by the control means 30 and the inert gas is supplied.

At this time, the flow rate detection means 23 detects the flow rate of the inert gas supplied in accordance with the leakage amount from the first shut-off valve 11 or the second shut-off valve 12, for example, as indicated by a broken line in FIG. The Then the control unit 30, after and the pressure detection value of the pressure detection means 22 in the first shut-off valve 11 and the second shut-off valve 12 is fully closed reaches the second pressure P _2, flow rate detecting means 23 When the flow rate detection value at 1 exceeds a predetermined threshold, it is determined that at least the first cutoff valve 11 and the second cutoff valve 12 are leaking. As shown by the solid line in FIG. 2, the flow rate detected by the flow rate detection means 23 is the pressure detection even when there is no leakage in the first cutoff valve 11 and the second cutoff valve 12. rather than zero at the same time that the pressure detection value of the unit 22 reaches the second pressure P _2, it becomes zero with a slight delay of several seconds. Therefore, for example, after several seconds (time T _{2 in} FIG. ₂ ) after the pressure detection value of the pressure detection means 22 reaches the second pressure P ₂ , the first shut-off valve 11 and the second shut-off valve 12 Leakage determination may be performed. Alternatively, if the flow rate detection value at the flow rate detection means 23 continuously exceeds a predetermined threshold exceeds a predetermined period, there is leakage at the first cutoff valve 11 and the second cutoff valve 12. You may make it perform determination of.

  For example, when the fluid shut off by the first shut-off valve 11 or the second shut-off valve 12 is a gas as in the present embodiment, the most leak specified in JIS (JIS B2005-4: 2008 edition) Even a “Class VI” valve with a small amount has a predetermined amount of leakage. Therefore, the threshold value for determining the leakage of the first cutoff valve 11 and the second cutoff valve 12 takes into account, for example, the value of the leakage amount defined in this JIS or the accuracy of the flow rate detection means 23 therefor. It is preferable to adopt the value determined as described above.

When it is determined that a leak has occurred in the first shut-off valve 11 or the second shut-off valve 12, for example, after the leak check is finished, as shown by a broken line in FIG. 21 continues the supply of the inert gas. Accordingly, since the inert gas is supplied at the second pressure P ₂ that is higher than the first pressure P ₁ that is the supply pressure of the combustible gas, the gas flow in the combustible gas supply pipe 10 is , The flow of the inert gas from the region A toward the pipes 10a and 10b. In other words, the flow of the combustible gas flowing from the conduit 10a to conduit 10b is blocked by the flow of inert gas supplied by the second pressure P _2. Therefore, for example, when a leak has occurred in the second shut-off valve 12, for example, although the combustible gas sealed in the region A at the beginning of the leak check may flow out to the pipe line 10a side, After all the combustible gas has flowed out, only the inert gas supplied from the inert gas supply pipe 20 flows to the pipe line 10a side. Therefore, the leakage of the combustible gas to the pipe line 10a is suppressed to the minimum amount enclosed in the region A. For example, the danger that the combustible gas that has flowed out mixes with the auxiliary combustible gas at the demand destination and ignites. Sex can be minimized.

  In addition, for example, even when leakage occurs in both the first cutoff valve 11 and the second cutoff valve 12, the combustible gas does not flow from the pipeline 10a toward the pipeline 10b. The risk of ignition of flammable gas at the customer or the like can be greatly reduced without immediately dealing with gas leakage.

On the other hand, as a result of the leak check, for example, when it is determined that no leakage has occurred in the first cutoff valve 11 and the second cutoff valve 12, for example, the control means 30 stops the control of the pressure control valve 21 ( Time T _{3 in} FIG. 2). More specifically, the opening degree of the pressure control valve 21 is kept fully closed. As a result, the supply of the inert gas is completely stopped, and the combustible gas is also shut off by the first shut-off valve 11 and the second shut-off valve 12. In addition,

According to the above embodiment, when the first shut-off valve 11 and the second shut-off valve 12 is closed, the control unit 30, a higher than the first pressure P ₁ is the pressure of the combustible gas Since the pressure control valve 21 is controlled based on the pressure detection value of the pressure detection means 22 so as to supply the inert gas at the pressure P ₂ of ₂ , at least of the first cutoff valve 11 or the second cutoff valve 12 when the leak occurs in either decreases the pressure detection value of the pressure detecting means 22, the inert gas through the pressure regulating valve 21 so as to restore the pressure to the lowered to the second pressure P ₂ is Supplied. Then, since the flow rate is detected by the flow rate detection means 23 provided in the inert gas supply pipe 20, when the flow rate detection value by the flow rate detection means 23 exceeds a predetermined threshold value, the first shut-off valve 11 or the second It can be immediately determined that at least one of the shut-off valves 12 is leaking. Therefore, the time required for determining the leakage of the shut-off valve can be greatly shortened as compared with the conventional case.

In particular, when there is no means for supplying an inert gas between the first shutoff valve 11 and the second shutoff valve 12 in the combustible gas supply pipe 10 as in the prior art, for example, the first shutoff valve Even if leakage occurs in the valve, the pressure in the region A surrounded by the first shut-off valve 11 and the second shut-off valve 12 is the first pressure P, which is the pressure upstream of the first shut-off valve 11. _Since it was maintained at ₁ , it was difficult to detect leakage. On the other hand, as in the present embodiment, the flow rate detecting means 23 is provided in the inert gas supply pipe 20 that supplies the inert gas at the second pressure P ₂ higher than the first pressure P _{1 as} the pressure in the region A. If provided, when a leak occurs from the first shut-off valve 11, the flow of the inert gas supplied to compensate for the reduced pressure can be detected by the flow rate detection means 23. Therefore, it is easy to detect the leakage of the upstream first shut-off valve 11, which is conventionally difficult to detect, between the first shut-off valve 11 and the second shut-off valve 12 constituting the double shut-off valve. can do.

Further, even when the leakage occurs, for example, in both the first shut-off valve 11 and the second shut-off valve 12, the pressure regulating valve 21, than the first pressure P ₁ is the pressure of the combustible gas by supplying an inert gas at a second higher pressure P _2, the first shut-off valve 11 the flow of combustible gas between the second shut-off valve 12 can be blocked by the inert gas. Therefore, the flow rate of the combustible gas flowing to the customer can be minimized.

  Note that when a flammable gas is severely shut off, a water seal valve may be used. However, the water seal valve cannot shut off a high-temperature gas or a high-pressure gas due to its principle. In this regard, according to the combustible gas supply device 1 of the present invention, even a high-temperature and high-pressure gas such as coke oven gas can be appropriately shut off.

  In the above embodiment, floating ball valves are used for the first shut-off valve 11 and the second shut-off valve 12, and the first shut-off valve 11 has a pressure in the region A corresponding to the first shut-off valve 11. Since the valve body of the ball valve is arranged to be pressed against the secondary (downstream) seat of the ball valve when the pressure in the upstream pipe line 10a becomes higher, the first When the shutoff valve 11 and the second shutoff valve 12 are fully closed and the inert gas is supplied into the region A at the second pressure P2, the valve bodies of the first shutoff valve 11 and the second shutoff valve 12 are used. Are pressed against the secondary sheet. Therefore, gas leakage can be effectively suppressed.

In the above embodiment, the control set value of the pressure by the pressure control valve 21 is the second pressure P _2. However, when setting the numerical value of the second pressure P ₂ , for example, as shown in FIG. In the combustible gas supply pipe 10, the second pressure detection means 40 as another pressure detection means is connected to the pipe line 10 a upstream of the first cutoff valve 11, and the pipe downstream of the second cutoff valve 12. A third pressure detecting means 41 as another pressure detecting means is installed in the passage 10b, and the pressure is detected while the second pressure detecting means 40 and the third pressure detecting means 41 continuously monitor the pressure. the value obtained by adding a predetermined value to the value of the higher values may be set second as the pressure P _2. In such a case, even if the pressure rises due to some factor on the gas holder 2 side which is a supplier or the catalyst reformer 3 side which is a demand destination, the first shut-off valve 11 and the second shut-off valve 12 are surrounded. The pressure in the region A thus maintained can always be kept higher than the pressure in the pipes 10a and 10b, and the shutoff of the combustible gas by the inert gas can be maintained.

In the above embodiment, the first shut-off valve 11 and the second shut-off valve 12 is fully closed, and after the pressure detection value of the pressure detecting means 22 has reached the second pressure P _2, the control unit 30 the first shut-off valve 11, had been determining the presence or absence of leakage from the second shut-off valve 12, the determination of the leak is not necessarily a pressure detection value of the pressure detecting means 22 has reached the second pressure P ₂ There is no need to do it later. For example, if there is a large amount of leakage from the first cutoff valve 11 or the second cutoff valve 12, or if leakage has occurred from both the first cutoff valve 11 and the second cutoff valve 12, or not the pressure reaches the second pressure P _2, it may take a longer time than usual to reach the second pressure P _2. In this case, for example, even after the lapse of the time T ₀ for starting the automatic control of the pressure regulating valve 21 a predetermined time, if the pressure detection value of the pressure detecting means 22 has not reached the second pressure P _2, the first It may be determined that at least one of the first cutoff valve 11 and the second cutoff valve 12 is leaking.

  As an example, the combustible gas supply device 1 according to the present embodiment is made of, for example, a combustible gas supply pipe 10, a first shut-off valve 11, and a second shut-off valve 12 having a diameter of 100 mm. An example of performing a leak check by applying to a supply system will be described.

The supply pressure of the combustible gas (first pressure P ₁ ) is about 5 kPa (gauge pressure), the first cutoff valve 11 and the second cutoff valve 12 are fully closed, and the pressure control valve 21 is automatically controlled. In a state where it has not started, the pressure detection value of the pressure detecting means 22 is assumed to be about 5 kPa, which is substantially the same as the supply pressure. Second pressure P ₂ shall be set to exceed ensure the supply pressure of the combustible gas, for example, 30 kPa.

  In addition, as the first shut-off valve 11 and the second shut-off valve 12, those having a leak amount satisfying “Class VI” of JIS are selected, and the maximum leak amount in that case is approximately 0. 0 per valve. It shall be 153 mL / min. The threshold for determining the presence or absence of leakage by the control means 30 is, for example, 0.310 mL / min, taking into account a slight margin to 0.306 mL / min, which is the sum of the maximum leakage amounts for two valves. did.

  When automatic control of the pressure control valve 21 is started after the first shut-off valve 11 and the second shut-off valve 12 are fully closed, the pressure control valve 21 is turned on until the pressure detection value of the pressure detection means 22 reaches 30 kPa. Inert gas is supplied through At this time, a predetermined amount of flow is detected by the flow rate detection means 23, but at this point, the control means 30 does not determine the presence or absence of leakage.

  Thereafter, when the pressure detection value of the pressure detection means 22 reaches 30 kPa, the pressure control valve 21 operates in the closing direction. Here, if there is no leakage in the first shut-off valve 11 and the second shut-off valve 12, the flow rate detection value by the flow rate detection means 23 falls within about 0.256 mL / m, which is smaller than the threshold value. On the other hand, when the detected flow rate value exceeds the threshold value, it is determined that at least one of the first cutoff valve 11 and the second cutoff valve 12 is leaking.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. The combustible gas supply device of the present invention is useful when supplying or shutting off the combustible gas using the double shutoff valve. However, those skilled in the art will be within the scope of the idea described in the claims. However, it is obvious that various changes or modifications can be conceived, and these are naturally understood to belong to the technical scope of the present invention. In particular, the combustible gas supply device of the present invention performs leak check using an inert gas and shuts off the fluid as in the present invention even when the fluid to be supplied and shut off is not a gas but a liquid. be able to. Also, the type of fluid can be applied to fluids other than flammable gases, and can be suitably used in places where strict shutoff is required, such as dangerous substances such as toxic gases and liquids.

DESCRIPTION OF SYMBOLS 1 Combustible gas supply apparatus 2 Gas holder 3 Catalytic reformer 10 Combustible gas supply pipe 11 1st shut-off valve 12 2nd shut-off valve 20 Inert gas supply pipe 21 Pressure control valve 22 Pressure detection means 23 Flow rate detection means 24 Check valve 30 Control means

Claims (4)

In the combustible gas supply apparatus having the first shut-off valve and the second shut-off valve provided in series with the combustible gas supply pipe for supplying the combustible gas,
An inert gas supply pipe for supplying an inert gas between the first cutoff valve and the second cutoff valve in the combustible gas supply pipe;
A pressure control valve that is provided in the inert gas supply pipe and controls the pressure of the inert gas supplied to the combustible gas supply pipe;
Pressure detecting means for detecting a pressure inside at least one of the combustible gas supply pipe and the inert gas supply pipe surrounded by the first shut-off valve, the second shut-off valve, and the pressure control valve;
A flow rate detecting means for detecting a flow rate of the inert gas flowing through the inert gas supply pipe;
When the first shut-off valve and the second shut-off valve are closed, the pressure is set such that the inert gas is supplied at a second pressure higher than the first pressure that is the pressure of the combustible gas. And a control means for controlling an opening degree of the pressure control valve based on a pressure detection value of the detection means. When the flow rate detection unit detects a flow rate exceeding a predetermined threshold after the pressure detection unit detects the arrival of the second pressure, the control unit detects the first cutoff valve or the second cutoff valve. The combustible gas supply device according to claim 1, wherein it is determined that at least one of the leaks has occurred. The first shut-off valve is provided upstream of the second shut-off valve;
At least one of the upstream side of the first shut-off valve in the combustible gas supply pipe or the downstream side of the second shut-off valve in the combustible gas supply pipe is provided inside the combustible gas supply pipe. The combustible gas supply apparatus according to any one of claims 1 and 2, further comprising another pressure detection means for detecting pressure. The first shut-off valve and the second shut-off valve are floating ball valves;
The first shut-off valve and the second shut-off valve are configured so that the inert gas is supplied from the inert gas supply pipe to the combustible gas supply pipe at a pressure higher than that of the combustible gas. 3. The valve body of the first shut-off valve and the valve body of the second shut-off valve are arranged so as to be pressed against the secondary seat, respectively. 3. The combustible gas supply device described in 1.

Images