Gas detection device

Abstract

[Problem] To detect, at an early stage, gas introduced into a flow path of a cooling liquid. [Solution] A gas detection device comprising: a branch unit that is connected to a flow path of a cooling liquid and guides gas flowing together with the cooling liquid to a branch flow path branched from the flow path; an inlet through which the gas guided to the branch flow path flows in; an intake for outside air provided below the inlet; an outlet for the gas provided above the inlet; a gas mixing unit for discharging, through the outlet, a gas mixture of the gas flowing in through the inlet and the outside air taken in through the intake; and a detection unit for detecting a predetermined gas to be detected from the gas mixture discharged from the gas mixing unit.

Description

Gas detection device

[0001] The present invention relates to a gas sensing device.

[0002] Generally, equipment such as hydrogen compressors and generators are liquid-cooled, cooled by a coolant such as water circulating in a closed cycle. A heat exchanger is provided in the closed cycle, and the coolant, which is warmed by cooling the equipment, is cooled by the heat exchanger and used again to cool the equipment.

[0003] A gas such as cooled hydrogen gas may be used to cool a liquid coolant in a heat exchanger, where the heated liquid coolant and the cooled gas exchange heat through a solid wall such as a metal wall, thereby cooling the liquid coolant and warming the gas.

[0004] Japanese Patent Application Publication No. 4-334948

[0005] In the heat exchanger described above, the coolant and gas such as hydrogen gas are separated by a solid wall, so gas does not normally get mixed into the coolant flow path. However, if the solid wall deteriorates, for example, due to corrosion of the metal that forms the solid wall, gas may leak into the coolant flow path, and flammable hydrogen gas, for example, may be dispersed to unintended locations.

[0006] Furthermore, if the equipment to be cooled by the coolant uses a gas such as hydrogen gas, there is a possibility that gas may leak into the coolant flow path not only in the heat exchanger but also in the cooled equipment. In this way, if the gas leaking into the coolant flow path is a flammable gas such as hydrogen gas or a toxic gas that is harmful to the human body, it is preferable to detect the gas leak early.

[0007] The present disclosure has been made in consideration of the above points, and aims to provide a gas detection device that can detect gas entering a coolant flow path at an early stage.

[0008] According to one aspect of the present disclosure, a gas detection device has a branching section connected to a coolant flow path and guiding gas flowing together with the coolant to a branching flow path branching from the flow path, an inlet through which gas guided to the branching flow path flows, an outside air intake located below the inlet, and a gas outlet located above the inlet, a gas mixing section that outputs from the outlet a mixed gas of the gas flowing in from the inlet and the outside air taken in from the intake, and a detection section that detects a predetermined target gas from the mixed gas output from the gas mixing section.

[0009] According to the present disclosure, gas entering the coolant flow path can be detected at an early stage.

[0010] Fig. 1 is a diagram showing the configuration of a gas detection device according to one embodiment. Fig. 2 is a diagram explaining ventilation control by a ventilation control unit. Fig. 3 is a diagram showing the configuration of a gas mixing unit. Fig. 4 is a diagram showing a specific example of detection performance. Fig. 5 is a diagram showing a modified example of a gas detection device according to one embodiment.

[0011] An embodiment of the present invention will be described below with reference to the accompanying drawings. The embodiment described below is an example and should not be construed as being limited by this description.

[0012] FIG. 1 is a diagram showing the configuration of a gas detection device 100 according to one embodiment. The gas detection device 100 shown in FIG. 1 is connected to a closed-cycle coolant flow path that circulates through a heat exchanger 200 and a cooling target 300, and detects hydrogen gas that enters the coolant flow path in the heat exchanger 200 or the cooling target 300. The heat exchanger 200 cools the coolant by heat exchange between a gas, such as hydrogen gas, and the coolant. The cooling target 300 is a device such as a hydrogen compressor or a generator, and is cooled by the coolant. The heat exchanger 200 and the cooling target 300 are connected by piping that serves as the coolant flow path, forming a closed cycle in which the coolant circulates.

[0013] Gas detection device 100 has a branch pipe 110 , a valve 120 , a ventilation control unit 130 , a gas mixing unit 140 , a gas detector 150 , and a drainage unit 160 .

[0014] Branch pipe 110 is connected to the coolant flow path and branches the coolant flow path. That is, branch pipe 110 has, for example, a T-shape and forms part of the coolant flow path that flows from heat exchanger 200 to cooled object 300, and also forms a branch flow path that guides some of the coolant flowing through this flow path to valve 120 above. Therefore, for example, if hydrogen gas is leaking into the coolant flow path in heat exchanger 200, branch pipe 110 guides some of the hydrogen gas mixed into the flow path to valve 120 together with the coolant.

[0015] The gas mixed into the coolant flow path is a water-insoluble gas, such as hydrogen gas, and flows in the form of bubbles along with the coolant in the coolant flow path. Because the density of this gas is smaller than that of the coolant, the gas flows into the branch flow path going upward and is guided to valve 120. The pressure of the liquid flow in the flow path causes the coolant to flow into the branch flow path going upward and be guided to valve 120.

[0016] Valve 120 regulates the flow of the coolant and hydrogen gas guided by branch pipe 110 into ventilation control unit 130. That is, valve 120 can be opened and closed by moving a lever, and when in the open state, allows the coolant and hydrogen gas guided from branch pipe 110 to flow into ventilation control unit 130, and when in the closed state, prevents the coolant and hydrogen gas guided from branch pipe 110 from flowing into ventilation control unit 130.

[0017] The ventilation control unit 130 collects hydrogen gas flowing in from the open valve 120 and controls the delivery to the gas mixing unit 140. Specifically, the ventilation control unit 130 has a float that floats on the coolant stored in an internal storage tank, and controls the opening and closing of the hydrogen gas outlet by the rise and fall of the float according to the height of the coolant surface.

[0018] FIG. 2 is a diagram illustrating ventilation control by the ventilation control unit 130. As shown in FIG. 2A, a float 132 that floats on the coolant is disposed in the storage tank 131 of the ventilation control unit 130. Coolant and hydrogen gas can flow in through the inlet 131a of the storage tank 131. However, when hydrogen gas is not mixed in the coolant flow path, the storage tank 131 is filled with only the coolant. At this time, the coolant level in the storage tank 131 is high, so the float 132 rises and pushes up the lever 133. A valve body 134 is connected to the top surface of the lever 133. When the lever 133 is pushed up, the outlet 131b of the storage tank 131 is closed by the valve body 134. Therefore, when hydrogen gas is not mixed in the coolant flow path, the outlet 131b is closed and the coolant does not flow out of the storage tank 131.

[0019] If hydrogen gas is mixed in the coolant flow path, the hydrogen gas flows into the storage tank 131, and as the hydrogen gas is collected in the storage tank 131, the liquid level of the coolant gradually drops. When the liquid level of the coolant drops, the float 132 descends, and the lever 133 and valve body 134 also descend, as shown in FIG. 2( b). As a result, the valve body 134, which had been closing the outlet 131 b, moves downward, and the outlet 131 b is opened. Therefore, as the amount of hydrogen gas remaining in the storage tank 131 increases, the hydrogen gas flows out from the outlet 131 b.

[0020] In this way, when hydrogen gas accumulates in the storage tank 131 , the ventilation control unit 130 opens the outlet 131 b to send the hydrogen gas therein to the gas mixer 140 .

[0021] The gas mixer 140 mixes the hydrogen gas sent from the ventilation control unit 130 with air and sends the resulting mixed gas to the gas detector 150. That is, the gas mixer 140 has an inlet for allowing hydrogen gas to flow in between an intake for taking in outside air and an outlet for sending gas to the gas detector 150, and mixes the hydrogen gas flowing in from the inlet with the air moving from the intake to the outlet, and sends the mixed gas out from the outlet. The gas mixer 140 also drains moisture that flows in from the ventilation control unit 130 together with the hydrogen gas via the drainage unit 160.

[0022] 3 is a diagram showing the configuration of the gas mixer 140. As shown in FIG. 3, the gas mixer 140 has a tank-like structure with multiple inlets and outlets. That is, one side of the tank 141, which can store gas, is provided with an inlet 142 through which hydrogen gas flows in, and the other side of the tank 141 is provided with an inlet 143 through which external air (fresh air) is taken in. The top surface of the tank 141 is provided with an outlet 144 through which the mixed gas of hydrogen gas and air is sent to the gas detector 150, and the bottom surface of the tank 141 is provided with a drain port 145 through which water that flows into the tank 141 together with the hydrogen gas is drained.

[0023] Since the inlet 142 opens into the tank 141 above the intake 143 that takes in outside air and below the outlet 144 that outputs the mixed gas, the hydrogen gas flowing in from the inlet 142 is mixed with the air moving from the intake 143 to the outlet 144. Therefore, the outlet 144 can reliably output the mixed gas of hydrogen gas and air to the gas detector 150.

[0024] Furthermore, moisture that flows in from inlet 142 together with hydrogen gas accumulates at the bottom of tank 141 and is drained from drain outlet 145 via drain section 160. This prevents moisture that accumulates at the bottom from reaching outside air intake 143 and flowing back from intake 143, and prevents the inflow of air from being obstructed.

[0025] The inlet 142 and the inlet 143 may be provided on the same side of the tank 141 .

[0026] The gas detector 150 draws the gas mixture from the gas mixer 140 and detects whether the gas mixture contains a predetermined target gas. Specifically, the gas detector 150 may be a general-purpose gas detector equipped with, for example, a hot-wire semiconductor sensor or a catalytic combustion sensor, and detects the target gas, for example, hydrogen gas. The gas detector 150 may use a combustion reaction using air (oxygen) to detect the target gas, but since the target gas, for example, hydrogen gas, is mixed with air in the gas mixer 140, it can reliably detect hydrogen gas. When the gas detector 150 detects the target gas, it may output an alarm sound or display a warning.

[0027] The drain unit 160 discharges the wastewater from the drain port 145 of the gas mixing unit 140, for example, to an external drain. The drain unit 160 passes the wastewater from above through an S-shaped pipe and discharges it to the drain below. As a result, some of the wastewater accumulates in the curved part of the S-shaped pipe of the drain unit 160, preventing gas from passing through. As a result, gas is prevented from flowing out from the gas mixing unit 140 via the drain unit 160, ensuring the reliability of gas detection.

[0028] In this way, gas detection device 100 captures hydrogen gas that has entered the coolant flow path, mixes it with air, and detects hydrogen gas from the resulting mixed gas using gas detector 150. This makes it possible to detect hydrogen gas that has entered the coolant flow path at an early stage.

[0029] 4 is a diagram showing a specific example of the relationship between the amount of hydrogen gas leaking into the coolant flow path and the detection time until the gas detection device 100 detects hydrogen gas. As shown by the linear approximation of the relationship between the leakage amount and detection time plotted in FIG. 4, the detection time tends to increase as the amount of hydrogen gas leaking into the coolant flow path decreases. For example, if the leakage rate of hydrogen gas is about 0.08 NL (normal liters) per minute, hydrogen gas can be detected in about 30 seconds to 1 minute, and if the leakage rate of hydrogen gas is about 0.04 NL per minute, hydrogen gas can be detected in about 1 minute 30 seconds to 2 minutes.

[0030] As described above, according to this embodiment, hydrogen gas that has entered the coolant flow path is collected and introduced into the tank through an inlet located between the tank's outside air intake and gas outlet, where the hydrogen gas and air are mixed, and the resulting mixed gas is then sent out from the outlet to the gas detector. This allows for early detection of gas that has entered the coolant flow path.

[0031] In the above embodiment, the ventilation control unit 130 collects hydrogen gas and controls its delivery to the gas mixing unit 140, but the hydrogen gas may also flow directly into the gas mixing unit 140 from the coolant flow path.

[0032] Figure 5 is a diagram showing a modified example of gas detection device 100 pertaining to one embodiment. In Figure 5, the same components as in Figure 1 are assigned the same reference numerals. As shown in Figure 5, gas detection device 100 does not have ventilation control unit 130, and when valve 120 is in an open state, hydrogen gas flows from the coolant flow path into inlet 142 of gas mixing unit 140. At this time, moisture that flows in from inlet 142 along with the hydrogen gas accumulates at the bottom of tank 141 and is drained from drain outlet 145 via drain unit 160.

[0033] In this way, gas detection device 100 according to the present embodiment can detect gas that has entered the flow path of the coolant with a simple configuration.

[0034] Furthermore, the diameter of branch pipe 110 may be larger than the diameter of the surrounding piping that forms the flow path of the coolant. That is, the diameter of the portion of branch pipe 110 that forms the flow path connecting heat exchanger 200 and object to be cooled 300 may be larger than the diameter of the surrounding piping, thereby reducing the flow rate of the coolant in branch pipe 110. By reducing the flow rate of the coolant in branch pipe 110, more of the hydrogen gas flowing with the coolant can be guided to the branched flow paths, further shortening the time until hydrogen gas is detected.

[0035] Furthermore, in the above embodiment, the gas that is mixed into the coolant flow path and is the target of detection by the gas detector 150 is described as hydrogen gas, but the gas detection device 100 can also be used to detect gases other than hydrogen gas.

[0036] REFERENCE SIGNS LIST 100 Gas detection device 110 Branch pipe 120 Valve 130 Ventilation control section 140 Gas mixing section 141 Tank 142 Inlet 143 Intake 144 Delivery outlet 145 Drain 150 Gas detector 160 Drain section

Claims

1. A gas detection device having: a branching section connected to a cooling liquid flow path and guiding gas flowing together with the cooling liquid to a branching flow path branching off from the flow path; a gas mixing section having an inlet through which gas guided to the branching flow path flows, an outside air intake located below the inlet, and a gas outlet located above the inlet, and which sends out from the outlet a mixed gas of the gas flowing in from the inlet and the outside air taken in from the intake; and a detection section which detects a specified target gas from the mixed gas sent out from the gas mixing section.

2. The gas detection device according to claim 1, further comprising a ventilation control section which collects the gas guided to said branch flow path and controls the delivery of the collected gas to said gas mixing section.

3. A gas detection device as claimed in claim 1 or 2, wherein the gas mixing section has a drain outlet for draining moisture which flows in together with the gas from the inlet.

4. A gas detection device as claimed in claim 1 or 2, wherein the detection unit has a gas detector that detects a specified target gas by a combustion reaction of the mixed gas.

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