Gas Supply System

Abstract

To provide a gas supply system capable of issuing a more accurate container switching signal.SOLUTION: A gas supply system 1 includes a plurality of LPG containers 10, a forced vaporization device 20, a liquid automatic switching device 40 for switching a connection state between a LPG container 10b on a standby side and the forced vaporization device 20 when a LPG container 10a on a use side becomes equal to or lower than first pressure, an automatic switching regulator 50 for adjusting the pressure of LP gas and introducing the LP gas from the LPG container 10b on the standby side when the LP gas from the LPG container 10a on the use side falls below second pressure, a pressure switch 60 for detecting that the LP gas on the automatic switching regulator 50 side is below third pressure, and an alarm device 41 for issuing a container switching signal in the case that it is switched to a connection state with the LPG container 10b on the standby side by the liquid automatic switching device 40 and that the LP gas on the automatic switching regulator 50 side is equal to or less than the third pressure on the basis of the pressure switch 60.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas supply system. [Background technology]

[0002] Conventionally, there is known a gas supply system that supplies fuel gas (LP gas) stored in a cylinder container (hereinafter referred to as an LPG container) to a consumer at an appropriate pressure. In this gas supply system, LP gas that has naturally evaporated in the LPG container is supplied to the consumer. Furthermore, when a large amount of LP gas must be supplied that exceeds the amount of LP gas generated by natural evaporation, the gas supply system forcibly vaporizes the liquefied LPG liquid in the LPG container and supplies it to the consumer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-216199 Summary of the Invention [Problem to be solved by the invention]

[0004] This gas supply system has a use-side LPG container and a backup LPG container, and when a drop in the pressure in the use-side LPG container is detected, the gas supply source is switched from the use-side LPG container to the backup LPG container. This switching is performed by an automatic switching regulator in the vapor phase line that supplies naturally vaporized LPG gas, and an automatic liquid switching device in the liquid phase line that supplies LPG liquid to the enhanced vaporizer.

[0005] In addition, the gas supply system has an automatic liquid switching device installed in the liquid phase line that detects the pressure inside the LPG container and switches from the use side to the reserve side when it falls below the switching pressure, and issues a container switching signal to that effect. Upon receiving this signal, the gas company will replace the LPG container on the use side.

[0006] However, depending on the temperature inside the LPG container, there is a possibility that the system will switch to the reserve side even though there is still liquid remaining. As the LPG liquid in the container evaporates and vaporizes as gas is consumed, the inside of the container is cooled by the latent heat of vaporization. When the inside of the container cools, the LP gas becomes difficult to evaporate, and the pressure may become low even though there is liquid LPG inside the container. For example, this may occur when a large amount of LP gas is consumed in a short period of time, or when the liquid phase is supplied for a long period of time.

[0007] If a container is replaced with such a remaining amount of liquid, the container replacement cycle will be shorter than expected, causing the originally planned container replacement schedule to be delayed and requiring adjustments to the delivery schedule.Furthermore, the container switching signal from the automatic liquid switching device may be judged as a malfunction or a false alarm, which may result in trouble with the consumer side without the replacement being carried out.

[0008] The present invention has been made to solve these conventional problems, and its purpose is to provide a gas supply system that can issue a more accurate container switching signal. [Means for solving the problem]

[0009] The gas supply system of the present invention comprises a plurality of gas containers for storing liquefied fuel gas; a forced vaporization device that introduces liquefied fuel gas from a use-side gas container among the plurality of gas containers and vaporizes it by heating; an automatic liquid switching device that switches from a first connection state between the use-side gas container and the forced vaporization device to a second connection state between a spare gas container among the plurality of gas containers and the forced vaporization device when the pressure of the use-side gas container falls below a first pressure; and an automatic switching regulator that introduces fuel gas that has naturally vaporized in the use-side gas container, adjusts the pressure, and then supplies it to a consumer, and introduces fuel gas that has naturally vaporized from the spare gas container when the pressure of the fuel gas introduced from the use-side gas container falls below a second pressure. The pressure of the fuel gas adjusted by the automatic switching regulator, or the pressure of the fuel gas supplied to the automatic switching regulator from the gas container on the user side and a signaling means for issuing a container switching signal when the automatic liquid switching device switches from the first connection state to the second connection state and the detection means detects that the pressure of the fuel gas on the automatic switching regulator side is the third pressure or less. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a gas supply system that can issue a more accurate container switching signal. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of a gas supply system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a first diagram illustrating the operation of the gas supply system according to the embodiment. [Figure 3] FIG. 10 is a second diagram illustrating the operation of the gas supply system according to the embodiment. [Figure 4] FIG. 10 is a third diagram illustrating the operation of the gas supply system according to the embodiment. [Figure 5] FIG. 10 is a configuration diagram of a gas supply system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below in accordance with preferred embodiments. Note that the present invention is not limited to the embodiments shown below and can be modified as appropriate without departing from the spirit of the present invention. In addition, in the embodiments shown below, some components are omitted from illustration and description, but it goes without saying that publicly known or well-known technologies are applied as appropriate to the details of the omitted technologies within the scope of the content described below.

[0013] Fig. 1 is a configuration diagram of a gas supply system according to an embodiment of the present invention. The gas supply system 1 shown in Fig. 1 supplies LP gas, which is a fuel gas, to a consumer. The gas supply system 1 includes a plurality of LPG containers (a plurality of gas containers) 10, a forced vaporization device 20, a heat source device 30, an automatic liquid switching device 40, an automatic switching regulator 50, a pressure switch (detection means) 60, various flow paths R1 to R8, and pressure regulators PR1 and PR2.

[0014] The multiple LPG containers 10 store LPG liquid, which is liquefied LPG gas, and include a user-side LPG container (user-side gas container) 10a and a spare-side LPG container (spare-side gas container) 10b. In the gas supply system 1, the LPG liquid in the user-side LPG container 10a is consumed first, and then the spare-side LPG container 10b is consumed.

[0015] The forced vaporization device 20 forcibly vaporizes the LPG liquid in the multiple LPG containers 10. This forced vaporization device 20 is equipped with a heat exchanger 21, and introduces the LPG liquid from the LPG container 10a on the usage side, and heats the LPG liquid in the heat exchanger 21 to vaporize it.

[0016] The heat source machine 30 generates hot water using, for example, vaporized LPG as fuel. The heat source machine 30 supplies the generated hot water to the heat exchanger 21 of the forced vaporization device 20. The supplied hot water is used for forced vaporization of LPG liquid in the forced vaporization device 20.

[0017] The first flow path R1 is a pipe connecting the use-side LPG container 10a among the multiple LPG containers 10 to the inlet side of the automatic liquid switching device 40, and supplies LPG liquid from the use-side LPG container 10a to the automatic liquid switching device 40. The second flow path R2 is a pipe connecting the spare-side LPG container 10b among the multiple LPG containers 10 to the inlet side of the automatic liquid switching device 40, and supplies LPG liquid from the spare-side LPG container 10b to the automatic liquid switching device 40. The third flow path R3 is a pipe connecting the outlet side of the automatic liquid switching device 40 to the inlet side of the forced vaporization device 20, and supplies LPG liquid that has passed through the automatic liquid switching device 40 to the forced vaporization device 20. The fourth flow path R4 is a pipe connecting the outlet side of the forced vaporization device 20 to the connection point A, and supplies LP gas forcibly vaporized in the forced vaporization device 20 to the connection point A.

[0018] When the pressure in the use-side LPG container 10a falls below a first pressure (e.g., 0.2 MPa), the automatic liquid switching device 40 switches from a connection state (first connection state) between the use-side LPG container 10a and the forced vaporization device 20 to a connection state (second connection state) between the spare-side LPG container 10b and the forced vaporization device 20. That is, the automatic liquid switching device 40 maintains the first connection state when the pressure in the use-side LPG container 10a exceeds the first pressure, and switches to the second connection state when the pressure in the use-side LPG container 10a falls below the first pressure. When switched to the second connection state, the forced vaporization device 20 forcibly vaporizes the LPG liquid from the spare-side LPG container 10b.

[0019] Furthermore, the automatic liquid switching device 40 is equipped with an alarm device (alarm means) 41. Ideally, the alarm device 41 issues a container switching signal when the LPG liquid in the LPG container 10a on the usage side runs out. The container switching signal may be sent directly to the gas company, or may be sent to the gas company via a relay device such as an NCU (Network Control Unit).

[0020] The forced vaporization device 20 also includes a back pressure valve V. The back pressure valve V is a protective valve for preventing abnormal pressure from being applied to the heat exchanger 21 of the forced vaporization device 20, and is provided near the inlet end of the heat exchanger 21. The back pressure valve V closes when the abnormal pressure exceeds a fourth pressure (e.g., 0.45 MPa), and opens when the abnormal pressure is less than the fourth pressure. The first regulator PR1 adjusts the pressure of the LP gas forcibly vaporized in the forced vaporization device 20 to a fifth pressure (e.g., 0.1 MPa), and is provided on the fourth flow path R4.

[0021] The automatic switching regulator 50 introduces LP gas that has evaporated naturally in the use-side LPG container 10a, adjusts the pressure, and then supplies it to the consumer. The automatic switching regulator 50 also introduces LP gas that has evaporated naturally from the reserve-side LPG container 10b when the pressure of the LP gas introduced from the use-side LPG container 10a falls below a second pressure (e.g., 0.07 MPa), which is the so-called lower limit pressure.

[0022] The fifth flow path R5 is a pipe connecting a use-side LPG container 10a among the multiple LPG containers 10 to the inlet side of the automatic switching regulator 50, and supplies naturally vaporized LP gas from the use-side LPG container 10a to the automatic switching regulator 50. The sixth flow path R6 is a pipe connecting a spare LPG container 10b among the multiple LPG containers 10 to the inlet side of the automatic switching regulator 50, and supplies naturally vaporized LP gas from the spare LPG container 10b to the automatic switching regulator 50. The seventh flow path R7 is a pipe connecting the outlet side of the automatic switching regulator 50 to connection point A, and supplies LP gas whose pressure has been adjusted in the automatic switching regulator 50 to connection point A. The eighth flow path R8 is a pipe connecting connection point A to the consumer side.

[0023] The pressure switch 60 is for detecting whether the pressure of the LP gas on the automatic switching regulator 50 side (gas phase side) is equal to or lower than a third pressure (for example, approximately 0.05 to 0.06 MPa). The pressure switch 60 is provided downstream of the automatic switching regulator 50, i.e., on the seventh flow path R7. When the pressure of the LP gas pressure-regulated by the automatic switching regulator 50 is equal to or lower than the third pressure, the pressure switch 60 outputs a signal to that effect to the alarm device 41. Note that although the gas supply system 1 according to this embodiment is equipped with the pressure switch 60, the system is not limited thereto, and may also be equipped with a pressure sensor that can output a signal corresponding to the pressure value.

[0024] The second regulator PR2 regulates the pressure of the LP gas forcibly vaporized in the forced vaporization device 20 to a sixth pressure (for example, 2.8 kPa), and is provided on the eighth flow path R8.

[0025] Here, the alarm device 41 issues a container switching signal when the following two conditions are met. The first condition is that the pressure in the user-side LPG container 10a falls below a first pressure (e.g., 0.2 MPa) and the connection state is switched from the first to the second. The second condition is that a signal indicating that the LP gas pressure is below a third pressure is received from the pressure switch 60. In other words, the alarm device 41 issues an alarm when switching is performed on the liquid phase side due to the first condition, and when a certain pressure drop is detected on the gas phase side due to the second condition.

[0026] Here, the third pressure, which is the signal output condition of the pressure switch 60, is preferably set to a pressure value between the regulated pressures (two regulated pressures) that are the outlet pressures of the automatic switching regulator 50. The automatic switching regulator 50 introduces naturally vaporized LP gas from the use-side LPG container 10a and supplies it to the consumer side at a first regulated pressure (e.g., 0.07 MPa), and introduces naturally vaporized LP gas from the reserve-side LPG container 10b and supplies it to the consumer side at a second regulated pressure (e.g., 0.03 MPa). Therefore, if the third pressure is set to a pressure value between the two regulated pressures, the pressure switch 60 can detect a decrease in the pressure of the LP gas introduced from the use-side LPG container 10a.

[0027] More specifically, when the pressure of the LP gas introduced from the user-side LPG container 10a is equal to or higher than the second pressure (the so-called lower limit pressure), the automatic switching regulator 50 adjusts the introduced LP gas to the first regulated pressure and supplies it to the consumer side. In other words, the pressure downstream of the automatic switching regulator 50 is the first regulated pressure, and the pressure switch 60 does not detect that the LP gas pressure is equal to or lower than the third pressure (for example, about 0.05 to 0.06 MPa).

[0028] On the other hand, when the LP gas from the user LPG container 10a falls below the second pressure, the automatic switching regulator 50 is no longer able to supply the LP gas at the first regulated pressure. In this state, the automatic switching regulator 50 also introduces LP gas from the backup LPG container 10b and supplies the LP gas to the consumer at the second regulated pressure. Therefore, the pressure switch 60 detects that the LP gas pressure is equal to or lower than the third pressure.

[0029] In this way, by setting the third pressure to a pressure value between the two adjustment pressures, the pressure switch 60 can detect that the pressure of the LP gas introduced from the user-side LPG container 10a has decreased, i.e., that the amount of LPG liquid in the user-side LPG container 10a has decreased.

[0030] Next, the operation of the gas supply system 1 according to this embodiment will be described. Figures 2 to 4 are diagrams illustrating the operation of the gas supply system 1 according to this embodiment. In Figures 2 to 4, the thick lines indicate the distribution paths of LPG liquid or LP gas.

[0031] First, as shown in Figure 2, it is assumed that the pressure in the use-side LPG container 10a exceeds the first pressure. In this case, the automatic liquid switching device 40 is set to the first connection state in which the use-side LPG container 10a and the forced vaporization device 20 are connected.

[0032] Furthermore, because the residual liquid volume in the user-side LPG container 10a is sufficient, the pressure of the LP gas in the fifth flow path R5 becomes equal to or higher than the second pressure. Therefore, the automatic switching regulator 50 adjusts the pressure of the LP gas that has naturally evaporated in the user-side LPG container 10a to the first adjusted pressure and supplies it to the consumer. Furthermore, because the automatic switching regulator 50 adjusts the pressure of the LP gas to the first adjusted pressure, the pressure switch 60 does not send a signal indicating that the pressure in the seventh flow path R7 is equal to or lower than the third adjusted pressure.

[0033] Furthermore, the alarm device 41 does not receive a signal from the pressure switch 60 indicating that the pressure is below the third pressure, and since the automatic liquid switching device 40 is in the first connection state, it does not issue a container switching signal.

[0034] Next, as shown in Figure 3, it is assumed that the pressure in the use-side LPG container 10a falls below the first pressure. In this case, the automatic liquid switching device 40 switches to the second connection state in which the backup-side LPG container 10b and the forced vaporization device 20 are connected.

[0035] If the pressure of the LP gas in the fifth flow path R5 is maintained at or above the second pressure, the automatic switching regulator 50 adjusts the pressure of the LP gas that has naturally evaporated in the user-side LPG container 10a to the first adjusted pressure and supplies it to the consumer. Also, because the automatic switching regulator 50 adjusts the pressure of the LP gas to the first adjusted pressure, the pressure switch 60 does not send a signal indicating that the pressure in the seventh flow path R7 is below the third adjusted pressure.

[0036] Furthermore, even though the automatic liquid switching device 40 has switched to the second connection state, the alarm device 41 does not receive a signal from the pressure switch 60 indicating that the pressure is equal to or lower than the third pressure. In other words, the first condition is met, but the second condition is not met. Therefore, the alarm device 41 does not issue a container switching signal.

[0037] Next, as shown in Figure 4, the remaining capacity of the user-side LPG container 10a decreases, and the pressure of the LP gas in the fifth flow path R5 can no longer be maintained at or above the second pressure. In this case, the automatic switching regulator 50 adjusts the pressure of the naturally vaporized LP gas in the backup LPG container 10b to the second adjusted pressure and supplies it to the consumer. Furthermore, since the automatic switching regulator 50 adjusts the pressure of the LP gas to the second adjusted pressure, the pressure switch 60 sends a signal indicating that the pressure in the seventh flow path R7 is below the third adjusted pressure.

[0038] In this case, the automatic liquid switching device 40 switches to the second connection state, and the alarm device 41 receives a signal from the pressure switch 60 indicating that the pressure is equal to or lower than the third pressure. In other words, both the first and second conditions described above are met. Therefore, the alarm device 41 issues a container switching signal.

[0039] In particular, the state shown in Fig. 3 may occur when, for example, a large amount of LP gas is consumed in a short period of time, or when the liquid phase supply time is long, even though there is still a residual liquid amount. However, the gas supply system 1 according to this embodiment also monitors a drop in gas phase pressure using the pressure switch 60, and does not issue a container switching signal in the state shown in Fig. 3, so that a more accurate container switching signal can be issued.

[0040] In the gas supply system 1 according to this embodiment, the automatic switching regulator 50 is equipped with a switching lever (not shown), and by rotating the switching lever, the reserve LPG container 10b can be set to the use side (to supply at the first adjusted pressure) and the use side LPG container 10a can be set to the reserve side (to supply at the second adjusted pressure).

[0041] In this manner, in the gas supply system 1 according to this embodiment, the alarm device 41 issues a container switching signal when the automatic liquid switching device 40 switches from a first connection state (connected to the use-side LPG container 10a) to a second connection state (connected to the backup-side LPG container 10b) and detects that the LP gas pressure at the automatic switching regulator 50 is equal to or lower than the third pressure. Therefore, even if the pressure at the use-side LPG container 10a drops due to temporary cooling or other reasons, causing the automatic liquid switching device 40 to switch the connection state, the container switching signal will not be issued until the pressure at the automatic switching regulator 50 drops below the third pressure. As a result, LP gas will be consumed from the use-side LPG container 10a until the pressure at the automatic switching regulator 50 drops below the third pressure, reducing the possibility of an alarm being issued when there is still liquid remaining. This allows for more accurate container switching signals to be issued.

[0042] Furthermore, the pressure switch 60 is located downstream of the automatic switching regulator 50, and the third pressure is set to a pressure between the first regulated pressure, which is the regulated pressure on the use side, and the second regulated pressure, which is the regulated pressure on the reserve side. Generally, the regulated pressure is higher on the use side and lower on the reserve side. When the remaining capacity of the use-side LPG container 10a becomes low, naturally vaporized LP gas is introduced from the reserve side and supplied downstream as LP gas at a lower regulated pressure. Therefore, by detecting the third pressure, which is between the first regulated pressure and the second regulated pressure, via the pressure switch 60, a container switching signal is generated on the gas phase side when use from the reserve-side LPG container 10b has begun. This allows for a more accurate container switching signal to be generated.

[0043] Next, a second embodiment of the present invention will be described. The gas supply system according to the second embodiment is similar to that of the first embodiment, but has a partially different configuration. The differences from the first embodiment will be described below.

[0044] 5 is a configuration diagram of a gas supply system according to the second embodiment. As shown in FIG. 5, the gas supply system 2 according to the second embodiment includes a first pressure switch (detection means) 71.

[0045] The first pressure switch 71 is provided on the fifth flow path R5 that connects the user-side LPG container 10a and the automatic switching regulator 50, and when the pressure in the fifth flow path R5 is below a pressure (third pressure) within a specified value of the second pressure, it sends a signal to the alarm device 41.

[0046] As described above, when the pressure of the LP gas introduced from the use-side LPG container 10a (fifth flow path R5) falls below the second pressure, the automatic switching regulator 50 begins to introduce the LP gas from the reserve-side LPG container 10b. That is, the first pressure switch 71 detects the timing when the LP gas is about to be introduced from the reserve-side LPG container 10b on the gas phase side, and transmits the detection result to the alarm device 41.

[0047] Therefore, the alarm device 41 of the second embodiment will issue a container switching signal when the automatic liquid switching device 40 switches from the first connection state to the second connection state and receives a signal from the first pressure switch 71 indicating that the pressure is below the third pressure.

[0048] The gas supply system 2 according to the second embodiment also includes a second pressure switch 72. The second pressure switch 72 has a similar configuration to the first pressure switch 71, and performs the same function as the first pressure switch 71 when the reserve side is switched to the use side.

[0049] In this way, according to the gas supply system 2 of the second embodiment, a more accurate container switching signal can be issued, similar to the first embodiment.

[0050] Furthermore, according to the second embodiment, the first pressure switch 71 is provided on the fifth flow path R5 connecting the use-side LPG container 10a and the automatic switching regulator 50, and the third pressure is set to a value within a specified value of the second pressure. Here, when the remaining capacity of the use-side LPG container 10a becomes low and falls below the second pressure, the automatic switching regulator 50 adjusts the LPG from the reserve side and supplies it to the consumer side. Therefore, by setting the third pressure to a value within a specified value of the second pressure, a container switching signal is generated on the gas phase side around the time when use from the reserve LPG container 10b begins. This allows for a more accurate container switching signal to be generated.

[0051] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and techniques from the embodiments and other techniques may be combined as appropriate within the scope of the spirit of the present invention.

[0052] For example, in the above embodiment, the alarm device 41 is configured as a part of the automatic liquid switching device 40, but this is not a limitation, and the alarm device 41 may be provided as a separate component from the automatic liquid switching device 40.

[0053] In addition, the back pressure valve V may be provided with a switch function, so that when the back pressure valve V opens, an ON signal is output to the heat source unit 30 to drive the heat source unit 30, and when the valve closes, an OFF signal is output to stop the heat source unit 30.

[0054] Furthermore, a thermovalve may be provided on the third flow path R3, and the thermovalve may be opened only when sufficient heat exchange is possible to vaporize the LPG liquid in the heat exchanger 21. Furthermore, in this embodiment, a hot water type is assumed as the forced vaporization device 20, but this is not limited to this, and the forced vaporization device may be an electric or gas type that houses an electric heater or a gas burner. [Explanation of symbols]

[0055] 1, 2: Gas supply system 10: Multiple LPG containers (multiple gas containers) 10a: LPG container used (gas container used) 10b: Spare LPG container (spare gas container) 20: Forced vaporizer 40: Automatic liquid switching device 41: Alarm device (alarm means) 50: Automatic switching regulator 60: Pressure switch (detection means) 71: First pressure switch (detection means) 72: Second pressure switch R1 to R8: Flow path

Claims

1. a plurality of gas containers for storing liquefied fuel gas; a forced vaporization device that introduces liquefied fuel gas from a gas container on a usage side among the plurality of gas containers and vaporizes it by heating; an automatic liquid switching device that switches from a first connection state between the gas container on the use side and the forced vaporization device to a second connection state between a spare gas container of the plurality of gas containers and the forced vaporization device when the pressure of the gas container on the use side becomes equal to or lower than a first pressure; an automatic switching regulator that introduces fuel gas naturally vaporized in the gas container on the use side, adjusts the pressure, and then supplies it to a consumer side, and introduces fuel gas naturally vaporized from the gas container on the reserve side when the pressure of the fuel gas introduced from the gas container on the use side falls below a second pressure; a detection means for detecting whether the pressure of the fuel gas pressure-regulated by the automatic switching regulator or the pressure of the fuel gas supplied from the gas container on the use side to the automatic switching regulator is equal to or lower than a third pressure; an alarm means for issuing a container switching signal when the automatic liquid switching device switches from the first connection state to the second connection state and when the detection means detects that the pressure of the fuel gas on the automatic switching regulator side is equal to or lower than the third pressure; A gas supply system comprising:

2. the detection means is provided downstream of the automatic switching regulator and detects whether the pressure of the fuel gas pressure-regulated by the automatic switching regulator is equal to or lower than the third pressure, The third pressure is set to a pressure between a first regulated pressure of the fuel gas introduced from the gas container on the use side and a second regulated pressure of the fuel gas introduced from the gas container on the reserve side, among the regulated pressures that become the outlet pressure of the automatic switching regulator.

2. The gas supply system according to claim 1.

3. The detection means is provided on a flow path connecting the gas container on the use side and the automatic switching regulator. and detecting whether the pressure of the fuel gas supplied from the gas container on the use side to the automatic switching regulator is equal to or lower than the third pressure, The third pressure is set to a value within a specified value from the second pressure.

2. The gas supply system according to claim 1.

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