Ion exchanger cartridge and method for molding cap of ion exchanger cartridge

Abstract

To provide a cartridge for an ion exchanger and a molding method of a cap of the cartridge for the ion exchanger, capable of restraining discharge of air from an exhaust hole from being obstructed.SOLUTION: The ion exchanger cartridge 14 is provided in an ion exchanger 11 having a case 13 provided in a cooling circuit in which a cooling liquid flows, and is detachably attached to the case 13 through an opening 12 at an upper end of the case 13. The cartridge 14 for the ion exchanger includes a cap 19 having a peripheral wall 21 and an upper wall 22, storing the ion exchange resin R inside, and having a lower opening 18 blocked by a first porous body 30 allowing the passage of the cooling liquid and preventing the passage of the ion exchange resin R. The peripheral wall 21 is provided with an exhaust hole 37 for discharging air inside the cap 19. The exhaust hole 37 extends in the vertical direction and has a width narrower than the diameter of the ion exchange resin R.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ion exchanger cartridge provided in an ion exchanger provided in a cooling circuit of a fuel cell, for example, and a method for molding a cap for the ion exchanger cartridge. [Background technology]

[0002] For example, a fuel cell is provided with a cooling circuit that circulates a coolant to cool the fuel cell stack in order to suppress a rise in temperature of the fuel cell stack during power generation. When the coolant in a fuel cell is thermally decomposed during power generation, ions are generated. This increases the ion concentration in the coolant, and these increased ions may cause metal corrosion or a decrease in the performance of the fuel cell. For this reason, the cooling circuit is provided with an ion exchanger that adsorbs and removes ions contained in the coolant (see, for example, Patent Document 1).

[0003] The ion exchanger of Patent Document 1 includes a case that is provided in a cooling circuit and has an open portion that opens upward, and a cartridge that is detachable from the case through the open portion. The cartridge has a peripheral wall and a top wall, and contains an ion exchange resin inside. The bottom opening of the cartridge is closed by a porous body that allows the coolant to pass through but prevents the ion exchange resin from passing through.

[0004] In a typical ion exchanger, when replacing an old cartridge attached to a case with a new one, the following problem may occur: When the old cartridge is removed from the case, the coolant level is present inside the case. If a new cartridge is inserted into the case in this state, the coolant level will rise, and there is a risk of the coolant leaking out of the opening in the case through the gap between the inner circumferential surface of the case and the circumferential wall of the cartridge.

[0005] Therefore, in the ion exchanger of Patent Document 1, an exhaust hole for discharging air from the cartridge is provided in the peripheral wall of the cartridge at a portion facing the inner peripheral surface of the case. As a result, even when a new cartridge is inserted into the case, the air in the cartridge is discharged through the exhaust hole, so the coolant in the case does not enter the cartridge. Therefore, the rise in the liquid level of the coolant in the case is suppressed compared to when an exhaust hole is not provided in the peripheral wall of the cartridge. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7139927 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the ion exchanger of Patent Document 1, when inserting a cartridge into the case, depending on the height of the coolant level in the case, the entire exhaust hole may be blocked by the coolant, which may prevent air from being discharged from the exhaust hole. [Means for solving the problem]

[0008] The means for solving the above problems and their effects will be described below. The ion exchange cartridge that solves the above problem is provided in an ion exchanger having a case disposed in a cooling circuit through which a coolant flows, and is detachably attached to the case of the ion exchanger through an opening at the top end of the case, and is provided with a cap having a peripheral wall and an upper wall and containing an ion exchange resin therein, the lower opening of which is blocked by a porous body that allows the coolant to pass through but prevents the ion exchange resin from passing through, and the peripheral wall is provided with an exhaust hole for discharging air from inside the cap, and the exhaust hole extends in the vertical direction and has a width narrower than the diameter of the ion exchange resin.

[0009] According to the above configuration, the exhaust hole extends in the vertical direction perpendicular to the liquid surface of the cooling liquid in the case. Therefore, when the ion exchange cartridge is attached to the case, the exhaust hole is less likely to be blocked entirely by the cooling liquid in the case, and therefore, obstruction to the exhaust of air through the exhaust hole can be suppressed.

[0010] A molding method for a cap for an ion exchange cartridge that solves the above-mentioned problems includes a cap that is provided in an ion exchanger having a case that is provided in a cooling circuit through which a coolant flows, the cap being detachably attached to the case of the ion exchanger through an opening at the top end of the case, the cap having a peripheral wall and an upper wall and containing an ion exchange resin therein, and a lower opening that is closed by a porous body that allows the coolant to pass through but prevents the ion exchange resin from passing through, the peripheral wall having an exhaust hole that exhausts air from inside the cap, the exhaust hole extending in the vertical direction and having a width narrower than the diameter of the ion exchange resin, and an outer surface of the peripheral wall The present invention relates to a molding method for a cap of an ion exchange cartridge, in which a recess having a bottom surface wider than the exhaust hole is formed in a cap of the ion exchange cartridge, and the exhaust hole is formed in the bottom surface of the recess, and the method includes a step of filling a cavity formed by clamping a fixed mold and a movable mold with molten resin, the movable mold having a first convex portion that forms the recess in the peripheral wall and a second convex portion that is provided on the first convex portion and forms the exhaust hole, the length of the first convex portion in the longitudinal direction of the second convex portion is equal to or greater than the length of the second convex portion, and the length of the first convex portion in the width direction perpendicular to the longitudinal direction of the second convex portion is longer than the length of the second convex portion.

[0011] According to the above method, the movable mold is configured such that the second protrusion is provided on the first protrusion. Therefore, particularly when the second protrusion has an elongated shape, the protrusion height of the second protrusion from the first protrusion can be shortened by adjusting the protrusion height of the first protrusion from the surface that forms the outer surface of the peripheral wall of the movable mold. Therefore, the strength of the second protrusion can be improved. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a cross-sectional view of an embodiment of an ion exchanger. [Figure 2] FIG. 2 is an enlarged view of part A in FIG. [Figure 3] FIG. 2 is a side view of an ion exchange cartridge. [Figure 4]FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG. 3. [Figure 5] FIG. 2 is a perspective view showing a main part of a movable mold. [Figure 6] FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 5. [Figure 7] FIG. 10 is a cross-sectional view showing the state of the main parts when the fixed mold and the movable mold are clamped together. [Figure 8] FIG. 10 is a cross-sectional view showing a state in which the ion exchange cartridge is being attached to the case. [Figure 9] FIG. 3 is a cross-sectional view showing a state in which an ion exchange cartridge is attached to a case. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment will be described below with reference to the drawings. <Ion exchanger 11> 1, for example, a cooling circuit of a fuel cell is provided with an ion exchanger 11 for removing ions contained in the coolant flowing through the cooling circuit. The ion exchanger 11 includes a substantially cylindrical case 13 with a bottom and an opening 12 at the top end, and an ion exchange cartridge 14 (hereinafter referred to as "cartridge 14") that is detachably attached to the case 13 through the opening 12 and that contains ion exchange resin R.

[0014] An inlet portion 15 for letting the coolant flow into the case 13 and an outlet portion 16 for letting the coolant flow out of the case 13 are provided at the bottom of the case 13. A throttle portion 17 is provided between the inlet portion 15 and the outlet portion 16 to connect them.

[0015] <Cartridge 14> The cartridge 14 includes a substantially cylindrical cap 19 with a bottom and a lower opening 18, and a tubular member 20 provided inside the cap 19 and coaxial with the cap 19. The cap 19 has a cylindrical peripheral wall 21 and an upper wall 22. The upper wall 22 has a cylindrical first reduced diameter portion 23 whose diameter is smaller than that of the peripheral wall 21, and a second reduced diameter portion 24 adjacent to and above the first reduced diameter portion 23 and whose diameter is smaller than that of the first reduced diameter portion 23.

[0016] 1 and 2, an external thread 26 is formed on the upper part of the outer surface of the peripheral wall 21, and is threaded into an internal thread 25 provided on the inner peripheral surface of the case 13. The cartridge 14 is removably attached to the case 13 by threading the external thread 26 of the cap 19 into the internal thread 25 of the case 13. At this time, the gap between the inner peripheral surface of the case 13 and the outer surface of the peripheral wall 21 of the cap 19 (cartridge 14) is sealed by the external thread 26 and the internal thread 25.

[0017] A support part 29 is provided on the outer peripheral surface of the upper part of the cylindrical member 20. The support part 29 has a plurality of protruding parts 27 that protrude outward and are arranged at intervals in the circumferential direction, and an annular connecting part 28 that connects the outer peripheral ends of each protruding part 27. The connecting part 28 of the support part 29 is joined to the inner peripheral surface of the first reduced diameter part 23 of the cap 19. This fixes the cylindrical member 20 to the cap 19. A gap is formed between the upper end of the cylindrical member 20 and the upper wall 22.

[0018] A ring-shaped first porous body 30, which is an example of a porous body, is attached between the outer peripheral surface of the lower part of the cylindrical member 20 and the inner peripheral surface of the lower part of the peripheral wall 21 of the cap 19 via a gasket (not shown). That is, the lower opening 18 of the cap 19 is closed by the first porous body 30. The first porous body 30 has a central hole through which the cylindrical member 20 is inserted. The first porous body 30 is configured to allow the coolant to pass through while preventing the ion exchange resin R from passing through.

[0019] An annular second porous body 31 is attached between the outer peripheral surface of the upper part of the cylindrical member 20 and the inner peripheral surface of the first reduced diameter portion 23 of the cap 19 via a gasket (not shown). The second porous body 31 has a central hole into which the cylindrical member 20 is inserted. The second porous body 31 is configured to allow the coolant to pass through while preventing the ion exchange resin R from passing through. The second porous body 31 is adjacent to the lower side of the support portion 29.

[0020] A support member 32 is removably attached to the lower opening 18 of the cap 19. The support member 32 has an inner annular portion 33 that is fitted onto the outside of the tubular member 20, a plurality of protruding portions 34 that protrude outward from the inner annular portion 33 and are arranged at intervals in the circumferential direction, and an outer annular portion 35 that connects the outer peripheral ends of the protruding portions 34. The support member 32 is adjacent to the underside of the first porous body 30.

[0021] A large number of granular ion exchange resin R are accommodated in the annular accommodation space formed within the cartridge 14 by the peripheral wall 21 of the cap 19, the cylindrical member 20, the first porous body 30, and the second porous body 31. The diameter of the ion exchange resin R is set to 0.5 mm, for example.

[0022] 1 to 3, when cartridge 14 is attached to case 13, a recess 36 is provided on the outer surface of peripheral wall 21 of cap 19 at a position facing the inner peripheral surface of case 13. Recess 36 is disposed immediately below and adjacent to male thread 26 on peripheral wall 21 of cap 19. Recess 36 is rectangular in shape, with its long side oriented in the up-down direction and its short side oriented in the circumferential direction of peripheral wall 21.

[0023] As shown in Figures 2 to 4, an exhaust hole 37 for discharging air from inside the cap 19 is formed in the center of the bottom surface of the recess 36 in the peripheral wall 21 of the cap 19 so as to penetrate the peripheral wall 21. The exhaust hole 37 is a slit that extends in the vertical direction, which is the axial direction of the cap 19. The bottom surface of the recess 36 is wider than the exhaust hole 37. In other words, the length of the bottom surface of the recess 36 in both the vertical direction and the circumferential direction of the peripheral wall 21 are both longer than the exhaust hole 37.

[0024] The vertical length of the exhaust hole 37 is set to 10 mm, for example. The circumferential width (length) of the inner end of the exhaust hole 37 is set to 0.3 mm, for example. That is, the circumferential width of the inner end of the exhaust hole 37 is smaller than the diameter of the ion exchange resin R. Therefore, the ion exchange resin R in the cap 19 is not discharged to the outside through the exhaust hole 37.

[0025] The exhaust hole 37 is configured so that the opening area increases toward the outer surface of the peripheral wall 21. That is, the width of the exhaust hole 37 in both the circumferential direction and the vertical direction gradually increases from the inner circumferential side toward the outer circumferential side of the peripheral wall 21. In other words, the inner circumferential surface of the exhaust hole 37 is tapered.

[0026] 1, in the ion exchanger 11 configured as described above, the coolant flowing through the cooling circuit flows into the case 13 through the inlet portion 15, as indicated by the arrows in Fig. 1. The coolant then flows through the first porous body 30, the ion exchange resin R, and the second porous body 31 in that order, and then flows into the cylindrical member 20 through the upper opening 38 of the cylindrical member 20.

[0027] The coolant that has flowed into the cylindrical member 20 flows downward through the cylindrical member 20. The coolant that has flowed downward through the cylindrical member 20 is discharged to the outside of the cartridge 14 from the lower opening 39 of the cylindrical member 20, and then flows out through the outflow portion 16. Ions in the coolant are removed by ion exchange as they pass through the ion exchange resin R.

[0028] <Cap 19 molding method> As shown in FIG. 7, the mold for molding the cap 19 includes a fixed mold 40 and a movable mold 41.

[0029] 5 and 6, the movable mold 41 has a first protrusion 42 that forms the recess 36 in the peripheral wall 21 of the cap 19, and a second protrusion 43 that is provided on the first protrusion 42 and forms the exhaust hole 37. The first protrusion 42 and the second protrusion 43 are both substantially rectangular parallelepiped-shaped. In the longitudinal direction of the second protrusion 43, the length of the first protrusion 42 is longer than the length of the second protrusion 43. In this case, the length of the first protrusion 42 is set to 15 mm, for example, and the length of the second protrusion 43 is set to 10 mm, for example.

[0030] In the width direction perpendicular to the longitudinal direction of the second protrusion 43, the length of the first protrusion 42 is longer than the length of the second protrusion 43. In this case, the length of the first protrusion 42 is set to 5 mm, for example. The second protrusion 43 is provided in the center of the first protrusion 42.

[0031] The protruding height of the first protrusion 42 from the outer molding surface 44 of the movable mold 41, which molds the general portion of the outer surface of the peripheral wall 21 other than the recessed portion 36, is set to, for example, 3 mm. The protruding height of the second protrusion 43 from the first protrusion 42, i.e., from the tip surface of the first protrusion 42, is set to, for example, 1 mm. Therefore, the distance from the outer molding surface 44 of the movable mold 41 to the tip of the second protrusion 43 is, for example, 4 mm. The width of the tip of the second protrusion 43 is set to, for example, 0.3 mm.

[0032] As shown in Fig. 7, when molding the cap 19, first, the fixed mold 40 and the movable mold 41 are clamped together. At this time, the tip of the second protrusion 43 of the movable mold 41 abuts against the fixed mold 40. Then, a cavity 45 is formed between the fixed mold 40 and the movable mold 41. Next, molten resin is injected into the cavity 45 to fill it. Then, the molten resin filled in the cavity 45 cools and solidifies, thereby molding the cap 19.

[0033] That is, the molding method of cap 19 includes a step of filling molten resin into cavity 45 formed by clamping fixed mold 40 and movable mold 41. Thereafter, fixed mold 40 and movable mold 41 are opened, and cap 19 is removed from the mold, thereby obtaining cap 19.

[0034] If the first protrusion 42 is not provided on the movable mold 41, the extremely narrow second protrusion 43 will protrude from the outer molding surface 44. As a result, the extremely narrow second protrusion 43 will protrude to a greater height from the outer molding surface 44, resulting in insufficient strength of the second protrusion 43. As a result, the second protrusion 43 will be deformed or damaged when it comes into contact with the fixed mold 40 when the fixed mold 40 and the movable mold 41 are clamped together, or when it is subjected to the flow pressure of the molten resin when the molten resin is filled into the cavity 45.

[0035] In this regard, the movable mold 41 of this embodiment has the first convex portion 42 as described above. Therefore, the first convex portion 42 reinforces the second convex portion 43 and reduces the protruding height of the second convex portion 43 by the protruding height of the first convex portion 42, thereby ensuring the strength of the second convex portion 43. Therefore, the second convex portion 43 is prevented from being deformed or damaged as described above.

[0036] <Operation of the embodiment> 2 and 8, when the cartridge 14 is attached to the case 13, the coolant present in the case 13 enters the cartridge 14 from the bottom thereof, as shown by the solid arrow in FIG. 8. This causes the air pressure inside the cartridge 14 to rise. Therefore, as shown by the dashed arrow in FIG. 8, the air inside the cartridge 14 is exhausted to the outside through the exhaust hole 37. This allows the coolant to enter further into the cartridge 14, thereby preventing the rise in the liquid level of the coolant inside the case 13.

[0037] Thereafter, as shown in FIG. 9, the male threads 26 of the cartridge 14 are screwed into the female threads 25 of the case 13, thereby attaching the cartridge 14 to the case 13.

[0038] Here, during the process of attaching cartridge 14 to case 13 as described above, there is a risk that exhaust hole 37 will be entirely blocked by the coolant, depending on the level of the coolant inside case 13. If exhaust hole 37 is entirely blocked by the coolant, the air inside cartridge 14 will be prevented from being discharged to the outside through exhaust hole 37. As a result, the level of the coolant inside case 13 will rise, causing the coolant to overflow from opening 12 at the top end of case 13.

[0039] In this regard, the cartridge 14 of this embodiment has an exhaust hole 37 that is elongated in the vertical direction. That is, the exhaust hole 37 extends in the vertical direction perpendicular to the liquid surface of the coolant in the case 13. Therefore, when attaching the cartridge 14 to the case 13, the exhaust hole 37 is less likely to be entirely blocked by the coolant in the case 13 compared to when the exhaust hole 37 extends, for example, horizontally.

[0040] Therefore, obstruction to the discharge of air from exhaust hole 37 is suppressed. As a result, the rise in the liquid level of the coolant inside case 13 is suppressed, and the coolant is prevented from overflowing from opening 12 at the top end of case 13. Note that exhaust hole 37 can continue to discharge air as long as it is not entirely blocked by coolant. For example, even if the lower half of exhaust hole 37 is blocked by coolant, the upper half can continue to discharge air.

[0041] <Effects of the embodiment> According to the embodiment described above in detail, the following effects are achieved. (1) The cartridge 14 includes a cap 19 having a peripheral wall 21 and an upper wall 22, containing an ion exchange resin R therein, and a lower opening 18 closed by a first porous body 30 that allows the coolant to pass through but prevents the ion exchange resin R from passing through. The peripheral wall 21 is provided with an exhaust hole 37 that exhausts air from inside the cap 19. The exhaust hole 37 extends in the vertical direction and has a width narrower than the diameter of the ion exchange resin R.

[0042] According to the above configuration, exhaust hole 37 extends in the vertical direction perpendicular to the liquid surface of the coolant inside case 13. Therefore, when cartridge 14 is attached to case 13, exhaust hole 37 is less likely to be entirely blocked by the coolant inside case 13, which prevents air from being obstructed from being discharged through exhaust hole 37.

[0043] (2) In the cartridge 14, the opening area of ​​the exhaust hole 37 increases as it approaches the outer surface of the peripheral wall 21. According to the above configuration, the air inside the cap 19 can be easily discharged to the outside through the exhaust hole 37. Therefore, the air inside the cap 19 can be efficiently discharged to the outside through the exhaust hole 37.

[0044] (3) In the cartridge 14, a recess 36 having a bottom surface wider than the exhaust hole 37 is formed on the outer surface of the peripheral wall 21. The exhaust hole 37 is formed in the bottom surface of the recess 36. According to the above configuration, when cartridge 14 is attached to case 13, recess 36 can increase the distance between vent hole 37 and the inner circumferential surface of case 13. This reduces pressure loss when air inside cap 19 is discharged through vent hole 37, allowing air inside cap 19 to be discharged to the outside through vent hole 37 more efficiently.

[0045] (4) The molding method for the cap 19 of the cartridge 14 includes a step of filling a cavity 45 formed by clamping a fixed mold 40 and a movable mold 41 with molten resin. The movable mold 41 has a first protrusion 42 that forms the recess 36 in the peripheral wall 21, and a second protrusion 43 that is provided on the first protrusion 42 and forms the exhaust hole 37. In the longitudinal direction of the second protrusion 43, the length of the first protrusion 42 is longer than the length of the second protrusion 43. In the width direction perpendicular to the longitudinal direction of the second protrusion 43, the length of the first protrusion 42 is longer than the length of the second protrusion 43.

[0046] According to the above method, the movable mold 41 is configured such that the second protrusion 43 is provided on the first protrusion 42. Therefore, particularly when the second protrusion 43 has an elongated shape, the protrusion height of the second protrusion 43 from the first protrusion 42 can be shortened by adjusting the protrusion height of the first protrusion 42 from the outer molding surface 44 that forms the outer surface of the peripheral wall 21 of the movable mold 41. Therefore, the strength of the second protrusion 43 can be improved.

[0047] (5) In the molding method of the cap 19 of the cartridge 14, the second protrusion 43 is provided in the center of the first protrusion 42. According to the above method, the entire second protrusion 43 is reinforced in a balanced manner by the first protrusion 42, so that the strength of the second protrusion 43 can be further improved.

[0048] <Example of change> The above embodiment can be modified as follows: Furthermore, the above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0049] In the movable mold 41, the second protrusion 43 does not necessarily have to be provided in the center of the first protrusion 42. In other words, the second protrusion 43 may be provided, for example, at the end of the first protrusion 42.

[0050] In the movable mold 41 , the length of the first protrusion 42 may be the same as the length of the second protrusion 43 in the longitudinal direction of the second protrusion 43 . The recess 36 may be omitted from the peripheral wall 21 of the cartridge 14.

[0051] The shape of the recess 36 may be changed as appropriate. When the shape of the recess 36 is changed, the shape of the first protrusion 42 is also changed to match the changed shape of the recess 36. In the cartridge 14, the opening area of ​​the exhaust hole 37 does not necessarily increase toward the outer surface of the peripheral wall 21. In other words, the opening area of ​​the exhaust hole 37 may decrease toward the outer surface of the peripheral wall 21, or the opening area may be constant throughout.

[0052] The peripheral wall 21 of the cartridge 14 may be provided with a plurality of exhaust holes 37 . [Explanation of symbols]

[0053] 11...Ion exchanger 12...Opening 13…Case 14...Ion exchange cartridge 15...Inflow part 16...Outlet 17...Diaphragm 18...Bottom opening 19...Cap 20...Cylindrical member 21...peripheral wall 22...Upper wall 23...First reduced diameter section 24…Second diameter reduction part 25...Female thread 26...External thread 27...Protrusion 28...Connection part 29...Support part 30...First porous body as an example of a porous body 31...Second porous body 32...Support member 33...Inner annular part 34...Protruding part 35...Outer annular part 36...recess 37...Exhaust vent 38...Upper opening 39...Lower opening 40…Fixed type 41…Movable type 42...First convex part 43...Second convex part 44…Outer molding surface 45...cavity R...Ion exchange resin

Claims

1. An ion exchange cartridge is provided in an ion exchanger having a case provided in a cooling circuit through which a coolant flows, the cartridge being detachably attached to the case of the ion exchanger through an opening at an upper end of the case, a cap having a peripheral wall and an upper wall, containing an ion exchange resin therein, and a lower opening of which is closed by a porous body that allows the coolant to pass through but prevents the ion exchange resin from passing through; The peripheral wall is provided with an exhaust hole for discharging air from inside the cap, The ion exchange cartridge according to claim 1, wherein the exhaust hole extends in a vertical direction and has a width narrower than a diameter of the ion exchange resin.

2. 2. The ion exchange cartridge according to claim 1, wherein the opening area of ​​the exhaust hole increases toward the outer surface of the peripheral wall.

3. a recess having a bottom surface wider than the exhaust hole is formed on the outer surface of the peripheral wall; 3. The ion exchange cartridge according to claim 1, wherein the exhaust hole is formed in a bottom surface of the recess.

4. A method for molding a cap for an ion exchange cartridge according to claim 3, comprising the steps of: a step of filling a cavity formed by clamping the fixed mold and the movable mold with molten resin; the movable mold has a first protrusion that forms the recess in the peripheral wall, and a second protrusion that is provided on the first protrusion and forms the exhaust hole, In the longitudinal direction of the second protrusion, the length of the first protrusion is equal to or greater than the length of the second protrusion, A molding method for a cap for an ion exchange cartridge, characterized in that the length of the first convex portion is longer than the length of the second convex portion in a width direction perpendicular to the longitudinal direction of the second convex portion.

5. In the longitudinal direction of the second protrusion, the length of the first protrusion is longer than the length of the second protrusion, 5. The method for molding a cap for an ion exchange cartridge according to claim 4, wherein the second protrusion is provided at a center portion on the first protrusion.

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