To provide a depressurizer with a function of depressurizing a filling hose separated from a filling device when a safety device (safety joint) operates (separates). A depressurizers (10, 11) according to the present invention are mounted to a filling hose (21) for filling hydrogen from a hydrogen filling apparatus (100) to a vehicle. In the present invention, it is preferable that on a main body portion (1) of the depressurizers (10, 11) is formed a depressurizing communication hole (1B) communicating with a hydrogen gas passage (1A); a plug (2) that can be inserted into the depressurizing communication hole (1B) is mounted; and on the depressurizing communication hole (1B) and the plug (2) are formed tapered portions (a pin tapered portion 2B of the plug 2 and a tapered portion 1BB of the depressurizing communication hole 1B) with complementary shapes.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2016-240321 filed on Dec. 12, 2016, the disclosure of which is incorporated herein by reference.

Not Applicable

BACKGROUND

1. Field of the Invention

The present invention relates to a depressurizing mechanism for flowing out high pressure gas (hydrogen for instance) from a piping (a filling hose mounted on a hydrogen filling apparatus, for instance) at a small flow rate.

2. Description of the Related Art

For example, to a vehicle using hydrogen gas as fuel, at a hydrogen filling station with a hydrogen filling apparatus is filled hydrogen after a filling nozzle and a vehicle side filling port (receptacle) are connected with each other. To the hydrogen filling apparatus is connected a filling hose having the filling nozzle at its end. Here, the filling by the hydrogen filling apparatus is performed while being controlled depending on the maximum using pressure of a hydrogen tank mounted in a vehicle. The applicant has proposed a hydrogen filling apparatus (refer to Japanese patent publication No. 2014-109350 gazette, for example), and the device is effective.

In the hydrogen filling station, when a vehicle runs to pull the filling hose while hydrogen is filled, the hydrogen filling apparatus falls, and devices are broken to inject hydrogen gas, so that it becomes dangerous condition. Then, a safety joint that separates when a tensile load more than a predetermined value is applied to the filling hose is mounted to divide the filling hose and the filling nozzle from the hydrogen filling apparatus, which prevents the hydrogen filling apparatus from falling and the devices from being broken. Here, when the safety joint separates, a shut-off valve in the safety joint immediately works to prevent hydrogen from being injected from the divided portions of the safety joint. In addition, on the hydrogen filling apparatus main body side is mounted a depressurizing mechanism, so that when the safety joint separates, high pressure gas is prevented from being rapidly injected.

However, in the conventional technique is not mounted the depressurizing mechanism on the filling nozzle or the filling hose. Then, when the safety joint works (separates), high pressure hydrogen gas cannot be removed from the filling hose on the vehicle side from the safety joint, so that a condition that high pressure hydrogen gas is filled in the filling hose is maintained. Under the condition, when the filling hose is dragged by a vehicle and a hole is formed on the filling hose, from the hole injects high pressure hydrogen gas, and due to momentum of the injection, the filling hose moves around (the filling hose becomes uncontrollable), which may damage a person and a vehicle. Therefore, it has been desired to develop a mechanism for removing high pressure hydrogen gas from the filling hose (for depressurizing the filling hose) after the safety joint works (separates) at a small flow rate, such depressurizing mechanism has not been proposed yet.

SUMMARY

The present invention has been made in consideration of the above problems in the prior art, and the object thereof is to provide a depressurizer with a function of depressurizing a filling hose that is divided from a filling device when a safety device (or a safety joint) works (separates).

Depressurizers (10,11) according to the present invention are characterized by being mounted to a filling hose (21) for filling hydrogen from a hydrogen filling apparatus (100) to a vehicle A.

It is preferable that the depressurizers (10,11) according to the present invention include: a main body portion (1) in which a hydrogen gas passage (1A) is formed, the main body portion (1) made of metal; a depressurizing communication hole (1B) formed in the main body portion (1), the depressurizing communication hole (1B) communicating with the hydrogen gas passage (1A); and a plug (2) capable of being inserted into the depressurizing communication hole (1B), the plug (2) made of metal, wherein tapered portions (a pin tapered portion2B of the plug (2), and a tapered portion1BB of the depressurizing communication hole (1B)) with complementary shapes are formed on the depressurizing communication hole (1B) and the plug (2). In addition, in the present invention, it is preferable that the depressurizers (10,11) further include a relief circuit (1C) formed in the main body portion (1), the relief circuit (1C) communicating with the depressurizing communication hole (1B) and the relief circuit (1C) having an outlet at a position apart from a spanner insertion hole of the plug (2).

In the present invention, it is preferable that a length (L) of a hydrogen gas passage side end portion (2A: a tip portion of a pin) of the plug (2) and a length (HL) of a hydrogen gas passage side end portion (1BA: a small diameter portion) of the depressurizing communication hole are long. Or in the present invention, it is preferable that a rotation stopping pin insertion hole (1D) is formed in the main body portion (1), the rotation stopping pin insertion hole (1D) locating around the plug (2).

With the present invention with the above construction, the depressurizers (10,11) are mounted to the filling hose (21), so that when the safety joint (20) separates, through the depressurizers (10,11) can be flown a high pressure hydrogen gas in the filling hose (21) at a small flow rate outside the filling hose (21) (outside the depressurizers10,11). Therefore, it is prevented that high pressure hydrogen gas rapidly injects, which prevents the filling hose (21) from moving around (the filling hose (21) becomes uncontrollable).

When the depressurizers (10,11) according to the present invention include a main body portion (1) in which a hydrogen gas passage (1A) is formed, the main body portion (1) made of metal; a depressurizing communication hole (1B) formed in the main body portion (1), the depressurizing communication hole (1B) communicating with the hydrogen gas passage (1A); and a plug (2) capable of being inserted into the depressurizing communication hole (1B), the plug (2) made of metal, wherein tapered portions (a pin tapered portion2B of the plug (2), and a tapered portion1BB of the depressurizing communication hole (1B)) with complementary shapes are formed on the depressurizing communication hole (1B) and the plug (2), a portion where the tapered portion (2B: pin tapered portion) of the plug (2) and the tapered portion (1BB) of the depressurizing communication hole (1B) contact with each other to constitute a metal seal, which completely shuts off high pressure hydrogen gas flowing in the hydrogen gas passage (1A). Then, at the depressurization, when the contact between the tapered portion (2B; pin tapered portion) of the plug (2) and the tapered portion (1BB) of the depressurizing communication hole (1B) is released, a gap formed between an outer periphery of a hydrogen passage side end portion (2A: a pin end portion, diameter φ) of the plug (2) and an inner periphery of a hydrogen passage side end portion (1BA: a small diameter portion, inner diameter d) of the depressurizing communication hole (1B) functions as an orifice (cross section: (π/4)(d2−φ2), annular gap), and the gap decreases pressure of high pressure hydrogen gas flowing in the orifice, so that injection velocity of the hydrogen gas flowing out of the depressurizers (10,11) becomes low, and it is prevented that the filling hose (21) moves around, that is, the filling hose (21) is prevented from becoming uncontrollable.

In addition, in the present invention, when a relief circuit is formed in the main body portion, the relief circuit communicating with the depressurizing communication hole and the relief circuit having an outlet at a position apart from a spanner insertion hole of the plug, even if a hexagonal rod spanner (S: hexagonal wrench) is inserted into a hexagonal hole formed on an upper portion of the plug (2) (2E: plug hexagonal hole) to rotate the plug (2), and metals are contact with each other to generate sparks, a position where the hydrogen gas flows out of the relief circuit (1C) is apart from a position where the sparks generate, so that a risk that the hydrogen gas ignites by the sparks becomes low, which improves safety of the depressurizers (10,11)

In the present invention, when a length (L) of a hydrogen passage side end portion (2A: a pin end portion) of the plug (2) and a length (HL) of a hydrogen passage side end portion (1BA: a small diameter portion) of the depressurizing communication hole (1B) are long (FIGS. 2 to 5), even if the hexagonal rod spanner (S: a hexagonal wrench) is inserted into the plug hexagonal hole2E to excessively rotate the plug (2), there is little possibility that the hydrogen passage side end portion (2A: a pin end portion) of the plug (2) is completely detached from the hydrogen passage side end portion (1BA: a small diameter portion) of the depressurizing communication hole (1B), and through the gap formed between pin end portion2A and the small diameter portion1BA flows the hydrogen gas, so that the gap functions as an orifice, and pressure of the high pressure hydrogen gas can be decreased. Therefore, it is not necessary to suppress the excessive rotation of the hexagonal rod spanner (S). On the other hand, in case that the length (L) of the pin end portion2A is short (FIGS. 6 to 8), forming a rotation stopping pin insertion hole (1D) for suppressing rotation of the hexagonal rod spanner (S) and inserting a rotation stopping pin (P) into rotation stopping pin insertion hole (1D) suppress the excessive rotation of the hexagonal rod spanner (S) when the hexagonal wrench S is inserted into the plug hexagonal hole (2e) to rotate the plug (2). As a result, it is prevented that the pin end portion (2A) is detached from the small diameter portion1BA, which prevents a cross section of the gap between the pin end portion (2A) and the small diameter portion (1BA) from becoming excessive. Then, it is maintained that the orifice (cross section (π/4)(d2−φ2), annular gap) functions so as to decrease pressure of the high pressure hydrogen gas.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be explained with reference to attached drawings. At first, the first embodiment of the present invention will be explained with reference toFIGS. 1 to 5. InFIG. 1, to a vehicle side filling port (receptacle)23of a hydrogen tank24of a vehicle A using hydrogen as fuel is connected a filling nozzle22. The filling nozzle22is mounted on an end of a filling hose21, and the filling hose21is connected to a hydrogen filling apparatus100. To the filling hose21is mounted a safety joint20, and the safety joint20has a function of separating when a tensile load more than a predetermined value is applied to the filling hose21.

A depressurizer10according to the first embodiment is mounted to the filling hose21on the side of the vehicle A from a separated safety joint20. Here, the safety joint20has been conventionally known, and at the same time that the safety joint20separates a hydrogen gas passage (not shown) is shut off, so that through the separated safety joint20does not inject high pressure hydrogen gas. In addition, in the hydrogen filling apparatus100is mounted a depressurizing mechanism (not shown), and by the depressurizing mechanism is discharged high pressure hydrogen gas through a region on the hydrogen filling apparatus100side from the separated safety joint20at a small flow rate, so that on the hydrogen filling apparatus100side does not occur an inconvenient condition by injecting the high pressure hydrogen gas (an inconvenient condition that hose is getting out of control, for instance). On the other hand, a high pressure hydrogen gas in the filling hose21on the vehicle A side from the separated safety joint20is flown through the depressurizer10outside the filling hose21(outside the depressurizer10) at a small flow rate. The depressurizer10according to the first embodiment will be explained in detail with reference toFIGS. 2 to 5.

InFIG. 2, the depressurizer10includes a metal main body portion1with a cuboid shape (including a projecting portion1E described later), and a metal plug2, and the plug2is constituted to engage with (be screwed to) a depressurizing communication hole1B of the main body portion1. InFIG. 2, on the left side of the main body portion1is formed a projecting portion1E, and into the projecting portion1E is inserted the filling hose21on the vehicle A side (refer toFIG. 1: filling hose21with the filling nozzle22). On the other hand, inFIG. 2, on the right side of the main body portion1is formed a concaved portion1F, and into the concaved portion1F is inserted the filling hose21on the filling device100(refer toFIG. 1) side. Meanwhile, it is possible that the projecting portion1E is connected to the filling hose21on the filling device100side and the concaved portion1F is connected to the filling hose21on the vehicle A side. InFIG. 2, at a central portion of main body portion1in a vertical direction is formed a hydrogen gas passage1A, and the hydrogen gas passage1A communicates the projecting portion1E with the concaved portion1F.

InFIG. 2, the depressurizing communication hole1B communicating with the hydrogen gas passage1A is formed to extend in a vertical direction. The depressurizing communication hole1B communicates from an upper surface1G of the main body portion1with the hydrogen gas passage1A, and with the depressurizing communication hole1B communicates a relief circuit1C (refer toFIGS. 4 and 5: not shown inFIG. 2). As described below, cross section of the relief circuit1C is set to be sufficiently small so as to generate a sufficient pressure loss in a hydrogen gas flowing on the bottom thereof. To the depressurizing communication hole1B is fitted the plug2(though engaging or screwing), and as shown inFIG. 4, engaging the plug2with the depressurizing communication hole1B shuts off the relief circuit1C from the hydrogen gas passage1A.

InFIG. 2, the depressurizing communication hole1B is constituted of: a small diameter portion1BA communicating with the hydrogen gas passage1A; a tapered portion1BB whose diameter is increasing upward from the small diameter portion1BA; the first middle diameter portion1BC extending upward from the tapered portion1BB; the second middle diameter portion1BD above the first middle diameter portion1BC; and a female screw portion1BE communicating with the upper surface1G. The plug2is constituted of: a pin end portion2A whose diameter at the lower end portion is the smallest, a pin tapered portion2B whose diameter is increasing upward from the pin end portion2A; a pin middle diameter portion2C extending upward from the pin tapered portion2B, and a male screw portion2D locating above the pin middle diameter portion2C and having a male screw on the outer periphery thereof.

When the plug2is fitted to the depressurizing communication hole1B, the pin end portion2A of the plug2is inserted into the small diameter portion1BA of the depressurizing communication hole1B. InFIG. 5, diameter of the pin end portion2A is shown as symbol “φ”, and inner diameter of the small diameter portion1BA of the depressurizing communication hole1B is shown as symbol “d”. Here, the diameter φ of the pin end portion2A is set to be slightly smaller than the inner diameter d of the small diameter portion1BA of the depressurizing communication hole1B (φ<d).

As shown inFIG. 2, the pin tapered portion2B of the plug2and the tapered portion1BB of the depressurizing communication hole1B have complementary shapes, and the pin tapered portion2B of the plug2contacts the tapered portion1BB of the depressurizing communication hole1B. Here, the both of the plug2and the main body portion1are made of metal, so that a portion that the pin tapered portion2B and the tapered portion1BB contact with each other constitutes a so-called “metal seal”. InFIG. 4, the metal seal portion exists near the hydrogen gas passage1A from the relief circuit1C. Then, by the metal seal portion that the pin tapered portion2B of the plug2and the tapered portion1BB of the depressurizing communication hole1B contact with each other, the relief circuit1C is completely shut off from the hydrogen gas passage1A.

InFIG. 2, on the first middle diameter portion1BC and the second middle diameter portion1BD of the depressurizing communication hole1B positions the pin middle diameter portion2C of the plug2. Then, between the pin middle diameter portion2C and the second middle diameter portion1BD is disposed an O-ring1H, and the O-ring1H is disposed on a step portion (shoulder portion) forming a boundary between the first middle diameter portion1BC and the second middle diameter portion1BD. The O-ring1H has a function of preventing high pressure hydrogen gas from injecting upward inFIG. 5through a gap between the plug2and the depressurizing communication hole1B when the plug2sufficiently lifts up from the depressurizing communication hole1B (a condition that engagement between the plug2and the main body portion1is released: refer toFIG. 5). In other words, under a condition shown inFIG. 2(a condition that the plug2is screwed to the depressurizing communication hole1B and engagement therebetween is complete), the O-ring1H does not perform seal function. Because the metal seal where the pin tapered portion2B of the plug2and the tapered portion1BB of the depressurizing communication hole1B contact with each other shuts off high pressure hydrogen gas flowing in the hydrogen gas passage1A.

As shownFIG. 2, on a region above the depressurizing communication hole1B is formed the female screw portion1BE, and to the female screw portion1BE is screwed the male screw formed on the outer periphery of the male screw portion2D of the plug2. In addition, on an upper surface of the plug2is formed a hexagonal hole2E (a plug hexagonal hole). When the plug2is attached to/detached from the depressurizing communication hole1B, as shown inFIG. 8, the hexagonal rod spanner S (a hexagonal wrench) is inserted into the plug hexagonal hole2E to be rotated. Meanwhile, the arrow C shown inFIG. 8shows the hydrogen filling apparatus side, and the arrow D shows the vehicle side.

As shown inFIG. 3, on the upper surface1G of the main body portion1, around the plug hexagonal hole2E of the plug2, rotation stopping pin insertion holes1D (six holes, for instance) are formed at equal intervals in the circumferential direction. As shown inFIG. 8, for example, under the condition that into one of the rotation stopping pin insertion holes1D is inserted a rotation stopping pin P, when the hexagonal rod spanner S is inserted into the plug hexagonal hole2E to be rotated, the rotation stopping pin P interferes with the hexagonal rod spanner S, so that it is prevented that the hexagonal rod spanner S excessively rotates. In case that the hexagonal rod spanner S excessively rotates; the plug2is excessively unfasten; and from the small diameter portion1BA of the depressurizing communication hole B is completely separated the pin end portion2A of the plug2, cross section of the gap between the plug2and the depressurizing communication hole B becomes excessively large, which does not allow a sufficient pressure loss to be given to the high pressure hydrogen gas. In contrast, when the depressurizer10is constituted such that at least one of the rotation stopping pin insertion holes1D is formed and the rotation stopping pin P interferes with the hexagonal rod spanner S, it is prevented that cross section of the gap between the plug2and the depressurizing communication hole1B becomes excessively large. But, as described below, in the first embodiment shown inFIGS. 1 to 5can be omitted the rotation stopping pin insertion holes1D.

As shown inFIGS. 4 and 5, the depressurizing communication hole1B communicates with the relief circuit1C in a region near a boundary between the tapered portion1BB and the first middle diameter portion1BC. As shown inFIGS. 2 and 4, under a condition the plug2is completely screwed to the depressurizing communication hole1B (a condition that hydrogen is filled without separating the safety joint20(FIG. 1), for instance), the pin tapered portion2B and the tapered portion1BB of the depressurizing communication hole1B contact with each other to constitute the metal seal, so that high pressure hydrogen gas flowing in the hydrogen gas passage1A is completely shut off by the metal seal, and does not flow in the relief circuit1C.

On the other hand, when the filling hose21is depressurized in case that the safety joint20separates for example, as shown inFIG. 8, into the plug hexagonal hole2E is inserted the hexagonal rod spanner S, and rotating the hexagonal rod spanner S in a depressurizing direction (counterclockwise, for instance) releases screwing between the female screw portion1BE of the depressurizing communication hole1B and the male screw portion2D of the plug2to lift up the plug2. By lifting up the plug2(unfastening the screwing), the pin tapered portion2B and the tapered portion1BB of the depressurizing communication hole1B are separated from each other to release the metal seal.

A condition that the metal seal is released is shown inFIG. 5. InFIG. 5, the diameter φ of the pin end portion2A is set to be slightly smaller than the inner diameter d of the small diameter portion1BA of the depressurizing communication hole1B (φ<d), and between the outer periphery of the pin end portion2A and the inner periphery of the small diameter portion1BA of the depressurizing communication hole1B is formed an annular gap whose cross section is (π/4)(d2−φ2). At the depressurization, through the annular gap flows a high pressure hydrogen gas filling in the hydrogen gas passage1A into the relief circuit1C, and through the relief circuit1C flows the high pressure hydrogen gas outside the depressurizer10(outside the filling hose) as shown by the arrow O. In addition, a hydrogen gas trying to inject upward inFIG. 5not to flow in the relief circuit1C is sealed by the O-ring1H arranged on the second middle diameter portion1BD.

Here, the difference between the diameter φ of the pin end portion2A and the inner diameter d of the small diameter portion1BA of the depressurizing communication hole1B is considerably small, so that the cross section (π/4)(d2−φ2) of the gap (annular gap between the outer periphery of the pin end portion2A and the inner periphery of the small diameter portion1BA of the depressurizing communication hole1B) is much smaller in contrast with the cross section (π/4)d2of the small diameter portion1BA of the depressurizing communication hole1B. Therefore, the annular gap whose cross section is (π/4)(d2−φ2) functions as an orifice, and a large pressure loss generates in the high pressure hydrogen gas flowing in the orifice. In addition to that, the cross section of the relief circuit1C is also small, which causes a pressure loss of the hydrogen gas in the relief circuit1C also. As a result, injection velocity of the hydrogen gas flowing out of the relief circuit1C (the arrow O) becomes low, which prevents that the filling hose21(FIG. 1) to which the depressurizer10is mounted moves around, that is, getting out of control by the hydrogen gas flowing out of the relief circuit1C.

Here, both of the plug2and the hexagonal rod spanner S are made of metal, so that there is a possibility that sparks generate when the hexagonal rod spanner S is inserted into the plug hexagonal hole2E to be rotated. In addition, when the rotation stopping pin P shown inFIG. 8is mounted, there is a possibility that sparks generate when the hexagonal rod spanner S contacts the rotation stopping pin P. In contrast, in the first embodiment, as clearly shown inFIGS. 4 and 5is formed a hydrogen gas outlet of the relief circuit1C at a position apart from the plug hexagonal hole2E. As a result, a position where a hydrogen gas flows out of the relief circuit1C is apart from a position where sparks generate by contacting metals with each other (the upper surface1G of the main body portion1), so that there is little possibility that flammable hydrogen gas ignites through the sparks, and it is safe around the depressurizer10.

In the first embodiment, as shown inFIG. 4for example, when the plug2is completely screwed to the depressurizing communication hole1B, the length L of the pin end portion2A (a vertical length inFIG. 4) and the length HL of the small diameter portion1BA of the depressurizing communication hole1B (vertical length inFIG. 4) are comparatively long, and the insertion length LW (a vertical length shown inFIG. 4) of the pin end portion2A into the small diameter portion1BA of the depressurizing communication hole1B is comparatively long also. Therefore, when into the plug hexagonal hole2E is inserted the hexagonal rod spanner S to be rotated, even if the hexagonal rod spanner S is excessively rotated, there is little possibility that from the small diameter portion1BA of the depressurizing communication hole1B is completely detached the pin end portion2A, so that a condition that the hydrogen gas flows through the annular gap between the small diameter portion1BA and the pin end portion2A, that is, the gap whose cross section is (π/4)(d2−φ2) is maintained, and the annular gap functions as an orifice, and a pressure loss can be given to the high pressure hydrogen gas. Therefore, in the first embodiment, it is unnecessary to suppress the excessive rotation of the hexagonal rod spanner S, and the rotation stopping pin P and the rotation stopping pin insertion hole1D can be omitted.

With the first embodiment shown inFIGS. 1 to 5, the depressurizer10is mounted to the filling hose21, and under a condition that the main body portion1and the plug2engage with each other, the portion that the pin tapered portion2B and the tapered portion1BB of the depressurizing communication hole1B contact with each other to constitute a metal seal, so that it can be completely shut off that the high pressure hydrogen gas flowing in the hydrogen gas passage1A flows into the depressurizing communication hole1B. At the depressurization, when the engagement between the plug2and the depressurizing communication hole1B is released, the gap (cross section(π/4)(d2−φ2), annular gap) formed between the outer periphery of the hydrogen passage side end portion2A (pin end portion) of the plug2and the inner periphery of the hydrogen passage side end portion1BA (small diameter portion) of the depressurizing communication hole1B functions as an orifice, so that a pressure loss generates in the high pressure hydrogen gas flowing in the orifice. Further, since the cross section of the relief circuit1C is small, when the hydrogen gas flows in the relief circuit1C, a pressure loss generates in the hydrogen gas. Then, injection velocity of the hydrogen gas (the arrow O shown inFIG. 5) flowing out of the depressurizer10(relief circuit1C) becomes slow to prevent the filling hose21to which the depressurizer10is mounted from moving around, that is, getting out of control.

In addition, in the first embodiment, since the hydrogen gas outlet of the relief circuit1C is formed at a position apart from the area above the plug2, even if sparks generate when into the plug hexagonal hole2E is inserted the hexagonal rod spanner S, a position where flammable hydrogen gas flows out (the arrow O shown inFIG. 5) is separated from a position where sparks generate, so that there is little possibility that hydrogen gas ignites due to the sparks, and it is safe around the depressurizer10.

Further, in the first embodiment, since the length L of the pin end portion2A of the plug2and the length HL of the small diameter portion1BA of the depressurizing communication hole1B are long, even if into the plug hexagonal hole2E above the plug is inserted the hexagonal rod spanner S to be rotated excessively, there is little possibility that the pin end portion2A of the plug2completely detaches from the small diameter portion1BA of the depressurizing communication hole1B, and the gap between the pin end portion2A of the plug2and the small diameter portion1BA of the depressurizing communication hole1B (cross section(π/4)(d2−φ2), annular gap) is maintained, and by the function of the gap as an orifice, a pressure loss generates in the hydrogen gas. Therefore, excessively rotating the hexagonal rod spanner S does not cause any inconvenience, and it is unnecessary to mount the rotation stopping pin insertion hole1D on the main body portion1of the depressurizer10, in addition, there is no need to insert the rotation stopping pin P thereto.

In addition, in the first embodiment shown in the drawings, between the pin middle diameter portion2C of the plug2and the second middle diameter portion1BD of the depressurizing communication hole1B is arranged the O-ring1H. When the engagement between the plug2and the depressurizing communication hole1B is released (refer toFIG. 5), even if a high pressure hydrogen gas tries to inject from the gap between the plug2and the depressurizing communication hole1B upward inFIG. 5without flowing in the relief circuit1C, it can be prevented by the O-ring1H.

Next, the second embodiment of the present invention will be explained with reference toFIGS. 6 to 8. In a depressurizer11according to the second embodiment, as clearly shown inFIGS. 6 and 7, the length L (a vertical length inFIG. 7) of the pin end portion2A of the plug2is clearly shorter than that shown inFIG. 4(in the first embodiment), and the insertion length LW (a vertical length inFIG. 6) of the pin end portion2A into the small diameter portion1BA is also shorter. At a depressurization shown inFIG. 7, when into the plug hexagonal hole2E is inserted the hexagonal rod spanner S to be excessively rotated, from the small diameter portion1BA of the depressurizing communication hole1B completely detaches the pin end portion2A of the plug2, and the cross section of the gap between the depressurizing communication hole B and the plug2enlarges, which does not function as an orifice. As a result, pressure loss generating in the high pressure hydrogen gas that remains in the hydrogen gas passage1A becomes small, which causes velocity of the high pressure hydrogen gas flowing out of the relief circuit1C to be high.

Then, in the second embodiment, as shown inFIG. 8, it is essential that on the upper surface1G of the main body portion1is formed the rotation stopping pin insertion hole1D to insert the rotation stopping pin P for suppressing rotation of the hexagonal rod spanner S. In other words, by the rotation stopping pin P is suppressed an excessive rotation of the hexagonal rod spanner S, and the gap between the pin end portion2A of the plug2and the small diameter portion1BA of the depressurizing communication hole1B is maintained as an annular one whose cross section is (π/4)(d2−φ2), and the gap provides a function of generating a pressure loss in hydrogen gas as an orifice. Not illustrated, in addition to the length L (a vertical length inFIG. 7) of the pin end portion2A of the plug2, the length HL (a vertical length inFIG. 7) of the small diameter portion1BA of the depressurizing communication hole1B can be set to be short, and in this case, it is essential that the rotation stopping pin insertion hole1D is formed to insert the rotation stopping pin P thereto.

InFIGS. 6 and 7, to members corresponding to those shown inFIGS. 1 to 5are attached the same numerals as those inFIGS. 1 to 5. Other construction and action effect of the second embodiment shown inFIGS. 6 to 8are the same as those of the first embodiment.

Since the embodiments shown in the drawings are merely examples, and the embodiments do not limit the technical scope of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

1main body portion (of depressurizer)1A hydrogen gas passage1B depressurizing communication hole1BA small diameter portion1BB tapered portion1C relief circuit1D rotation stopping pin insertion hole2plug2A pin end portion2B pin tapered portion10,11depressurizers20safety joint21filling hose100hydrogen filing apparatusHL length of small diameter portion of depressurizing communication holeL length of pin end portion of plugLW insertion length of pin end portion into small diameter portionP rotation stopping pinS hexagonal rod spanner