Strainer

Abstract

This reduces the likelihood of a shortage in hydrogen gas supply caused by a strainer on the hydrogen flow path side of fuel cells and other devices becoming blocked due to freezing. [Solution] The strainer has a hydrogen gas inlet and comprises a first mesh section where a mesh is arranged, and a second mesh section spaced apart from the first mesh section and located downstream of the first mesh section along the path. The mesh arranged in the first mesh section and the mesh arranged in the second mesh section are positioned at different locations when viewed in the direction of the path, and the mesh of the second mesh section is located inside the mesh of the first mesh section.

Description

Technical Field

[0001] The present disclosure relates to a strainer provided in a hydrogen supply passage.

Background Art

[0002] In a fuel cell, a filter is provided so that foreign matter, particularly metallic foreign matter, does not enter the hydrogen supply passage. During the operation stop of the fuel cell, anode scavenging is known to be performed to prevent the filter from freezing and blocking the hydrogen supply passage (see, for example, Patent Document 1). As the filter, for example, one using a metal mesh can be used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] If scavenging is performed when stopping the fuel cell as in Patent Document 1, moisture will not remain attached to the filter, so freezing of the filter when the fuel cell stops can be prevented, and blockage of the hydrogen supply passage after the fuel cell starts can be avoided.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, there is a possibility that the filter may freeze during operation or startup of the fuel cell. Simply performing scavenging at the time of stop cannot eliminate the possibility that the filter will freeze and block the hydrogen supply passage when starting below the freezing point. When the mesh provided in front of the strainer freezes, the pressure loss in the hydrogen supply passage increases, and there is a risk that the supply amount of hydrogen will be insufficient. If the anode circulation gas is insufficient and power generation is performed with hydrogen deficiency, there is also a risk of inducing a problem in the fuel cell stack.

Means for Solving the Problems

[0006] This disclosure can be implemented in the following forms or applications:

[0007] The strainer of this disclosure is placed in a hydrogen gas path. The strainer has an inlet for the hydrogen gas and comprises a first mesh section in which a mesh is arranged, and a second mesh section spaced apart from the first mesh section and provided downstream of the first mesh section along the path, wherein the mesh arranged in the first mesh section and the mesh arranged in the second mesh section are arranged at different positions when viewed in the direction of the path, and the mesh of the second mesh section is arranged inside the mesh of the first mesh section.

[0008] In this way, even if the mesh becomes blocked due to freezing, the mesh of the first mesh section and the mesh of the second mesh section are in different positions, ensuring that hydrogen gas can flow while avoiding both. Therefore, if this strainer is used in hydrogen-consuming equipment such as fuel cells, the supply of hydrogen gas can be ensured even if freezing occurs, and the operation of the hydrogen-consuming equipment will not be hindered, or the degree of hindering can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] An explanatory diagram showing the configuration of the strainer. [Figure 2] An explanatory diagram showing the flow of hydrogen gas in a strainer. [Figure 3] An explanatory diagram showing other shapes of the downstream mesh section of the strainer. [Modes for carrying out the invention]

[0010] A. First Embodiment: The strainer of this embodiment is used in the fuel gas supply section of a fuel cell system. First, the configuration of the strainer 70 will be described. The configuration of the strainer 70 will be described with reference to Figure 1. As shown in the figure, the strainer 70 comprises a first mesh section 110 located on the hydrogen gas inlet 105 side, a second mesh section 120 spaced apart downstream thereof, and a body section 130 connecting the two. The mesh MS located in the first mesh section 110 and the mesh MS located in the second mesh section 120 are located at different positions when viewed in the direction of the hydrogen gas path, and the mesh MS of the second mesh section 120 is located inside the mesh MS of the first mesh section 110, that is, in a position that does not protrude when viewed from the direction of the path.

[0011] The structural body 130 comprises a first base body 131 to which the first mesh section 110 is attached, a second base body 132 to which the second mesh section 120 is attached, and four columnar bodies 134 connecting the two. The structural body 130 may also be fixed to the first mesh section 110 or the second mesh section 120. In this embodiment, since the strainer 70 is housed in the mixing pipe 62, the structural body 130 is constructed using four columnar bodies 134, but it can also be constructed integrally using cylindrical members.

[0012] The first mesh section 110 is inserted into the main body section 130 from the rear, integrating with the second mesh section 120, and is then inserted into and fixed in the mixing piping described later.

[0013] The first mesh section 110 consists of a conical base cylinder section 111 and a cylindrical section 112 connected to the base cylinder section 111. Both the base cylinder section 111 and the cylindrical section 112 have four openings formed on their outer circumference, and a mesh MS of a predetermined fineness is attached to these openings. The coarseness of the mesh MS is set so that the openings are smaller than the size of the foreign matter to be removed. Since both the base cylinder section 111 and the cylindrical section 112 are cylindrical bodies, their centers are open.

[0014] Figure 1 shows an end view (top) of the strainer 70 cut along the central axis, which is the direction of hydrogen gas inflow; a view of the strainer 70 from the direction of arrow A (inlet side) (bottom left); and a view of the second mesh portion 120 of the strainer 70 from the direction of arrow B (bottom right). As shown in the figure, the inlet side of the first mesh portion 110 has a shape that is concave inward. The mesh MS viewed from the inlet side has a donut shape as a whole, and its outer diameter is D1. The mesh MS of the first mesh portion 110 is divided into four regions in the circumferential direction, but it is not necessary to divide it and it may be formed as a single unit. Alternatively, it may be divided into two, three, or even five or more. Also, as shown in Figure 1, the mesh MS portion of the first mesh portion 110 has a height L1.

[0015] The second mesh section 120 is located at a predetermined distance L3 from the tip of the cylindrical section 112 of the foundation cylinder section 111, and includes a cylindrical end section 122 attached to the base member 121. A mesh MS with an outer diameter D2 is placed in one of the openings of this end section 122. The coarseness of this MS may be the same as the mesh MS of the first mesh section 110, or it may be coarser or finer. The end section 122 is fixed to the base member 121, but since the base member 121 is provided with an opening 125, the inflow of hydrogen gas into the end section 122 is not obstructed. The end section 122 has a height of L2.

[0016] The dimensions D1, D2, L1, L2, and L3 of these parts satisfy the following relationship. D2 > D1 …(1) L1, L2 > L3 …(2)

[0017] According to the strainer 70 described above, if the fuel gas supply pipeline and the like are sufficiently scavenged when the fuel cell is stopped, even if the environment surrounding the fuel cell drops below freezing when the fuel cell is stopped, the adhesion of moisture to the mesh MS of the strainer 70 will be suppressed, and the strainer 70 will not freeze and the mesh MS will not become clogged. Therefore, when the fuel cell is started, the strainer 70 is not clogged due to freezing, and hydrogen gas is supplied to the fuel cell through the MS of the strainer 70. This is schematically shown in Figure 2 as arrow HN. The strainer 70 is installed in the fuel gas mixing pipe 62. The inlet 105 side of the strainer 70 is connected to the hydrogen gas supply pipe 61, which is supplied with hydrogen gas from the fuel tank, etc., and to the fuel off-gas pipe 49, through which hydrogen off-gas discharged from the fuel cell circulates. The hydrogen gas flowing in from the inlet 105 of the strainer 70 passes through the mesh MS of the first mesh section 110, and then through the mesh MS of the second mesh section 120.

[0018] On the other hand, if the ambient temperature drops significantly below freezing during operation or startup of the fuel cell, it is conceivable that moisture adhering to the mesh MS of the strainer 70 may freeze. In such cases, the mesh MS will become blocked by the frozen water (ice). In this embodiment, the strainer 70 has an opening 118 in the first mesh section 110 and an opening 125 in the second mesh section 120. Therefore, as shown in Figure 2, hydrogen gas HA enters from the inlet 105 side, passes through the openings 118 and 125, and is supplied to the fuel cell. As a result, even if the strainer 70 freezes, a fuel shortage will not occur in the fuel cell, and adverse effects on the performance of the fuel cell will be suppressed. Therefore, even if the mesh MS of the strainer 70 freezes during operation or startup of the fuel cell, hydrogen gas can pass through the strainer 70, and a shortage of hydrogen gas supplied to the fuel cell, which would cause deterioration of the fuel cell cells, will not occur.

[0019] B. Variations: The strainer 70 is often designed to be in a horizontal state during use. However, when the fuel cell is provided in a moving body such as a vehicle, etc., it may not be possible to maintain a horizontal state during use. In preparation for such a state, that is, when the end portion 122 is inclined, it is also effective to have a shape such that when a foreign object such as a metal piece enters the inside of the end portion 122 of the second mesh portion 120, it is difficult for this to move upstream.

[0020] Such forms are illustrated in FIG. 3. Illustration (A) shows a structure in which the end portion 122A has a larger diameter toward the downstream side where the mesh MS is provided, and illustration (B) shows a structure in which a step portion ST with a large diameter is provided on the mesh MS side of the end portion 122B. By adopting such a structure, it is possible to suppress the possibility that foreign matter once captured by the second mesh portion 120 returns upstream.

[0021] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve part or all of the above-described problems, or to achieve part or all of the above-described effects. Also, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

Explanation of Reference Numerals

[0022] 49... Fuel off-gas pipe, 61... Gas supply pipe, 62... Fuel gas mixing pipe, 70... Strainer, 105... Inlet, 110... First mesh portion, 111... Base cylinder portion, 112... Cylindrical portion, 118... Opening, 120... Second mesh portion, 121... Base member, 122, 122A, 122B... End portions, 125... Opening, 130... Housing portion, 131... First base portion, 132... Second base portion, 134... Column body, MS... Mesh, ST... Step portion

Claims

[Claim 1] A strainer placed in the hydrogen gas path, A first mesh section having an inlet for the hydrogen gas and having a mesh arranged therein, A second mesh section is spaced apart from the first mesh section and is located downstream of the first mesh section along the path, Equipped with, A strainer in which the mesh arranged in the first mesh section and the mesh arranged in the second mesh section are positioned at different locations when viewed in the path direction, and the mesh of the second mesh section is positioned inside the mesh of the first mesh section.

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