VAPORIZER

Abstract

A vaporizer, through which a liquid heat medium and liquid hydrogen flow, causing the heat medium to vaporize the liquid hydrogen, includes: a spiral tube, spirally wound, in which liquid hydrogen flows; a casing being a hollow long member housing the spiral tube thereinside, the heat medium flowing on an outer surface of the spiral tube; and a spacer being a long member disposed inside a winding inner diameter of the spiral tube.

Claims

1. A vaporizer, through which a liquid heat medium and liquid hydrogen flow, causing the heat medium to vaporize the liquid hydrogen, the vaporizer comprising: a spiral tube, spirally wound, in which the liquid hydrogen flows; a casing being a hollow long member housing the spiral tube inside, the heat medium flowing on an outer surface of the spiral tube; and a spacer being a long member disposed inside a winding inner diameter of the spiral tube.

2. The vaporizer according to claim 1, wherein the spacer is a hollow closed cross-section member extending in a longitudinal direction of the casing, the spacer forming an annular channel between the spacer and an inner surface of the casing, the annular channel extending in the longitudinal direction of the casing, the annular channel being a channel through which the heat medium flows in the longitudinal direction.

3. The vaporizer according to claim 2, wherein the spiral tube is disposed in the annular channel so as to have a gap between the spiral tube and the inner surface of the casing, and a gap between the spiral tube and an outer surface of the spacer.

4. The vaporizer according to claim 3, wherein the casing includes a large cylindrical portion and large end plates attached to respective ends of the large cylindrical portion, and further includes a rod-shaped outer tube receiver attached to an inner surface of the large cylindrical portion, the rod-shaped outer tube receiver extending in the longitudinal direction, the spacer includes a small cylindrical portion and small end plates attached to respective ends of the small cylindrical portion, and further includes an inner tube receiver attached to an outer surface of the small cylindrical portion, the inner tube receiver extending in the longitudinal direction, the inner surface of the large cylindrical portion and the outer surface of the small cylindrical portion form the annular channel, and the spiral tube is mounted in the annular channel so as to cause the outer tube receiver to form a gap between a spiral tube surface on a winding outer diameter side and the inner surface of the large cylindrical portion and so as to cause the inner tube receiver to form a gap between a spiral tube surface on a winding inner diameter side and the outer surface of the small cylindrical portion.

5. The vaporizer according to claim 1, wherein the heat medium is LLC or water.

6. The vaporizer according to claim 2, wherein the heat medium is LLC or water.

7. The vaporizer according to claim 3, wherein the heat medium is LLC or water.

8. The vaporizer according to claim 4, wherein the heat medium is LLC or water.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0018] Embodiment(s) of the present disclosure will be described based on the following figures, wherein:

[0019] FIG. 1 is a sectional view of a vaporizer of an embodiment; and

[0020] FIG. 2 is a sectional view of the vaporizer of the embodiment, showing a section taken along a line A-A shown in FIG. 1.

DESCRIPTION OF EMBODIMENTS

[0021] A vaporizer 100 of an embodiment will be described below with reference to the drawings. As shown in FIG. 1, the vaporizer 100 includes a casing 10, a spiral tube 20, and a spacer 30. In the following description, the longitudinal direction of the casing 10 is a Y-direction, the direction orthogonal to the Y-direction is an X-direction, and the direction orthogonal to the X- and Y-directions is a Z-direction. In addition, in the description the direction in which the heat medium flows inside the casing 10 is the Y-direction plus side, and the opposite direction is the Y-direction minus side. LH.sub.2 and H.sub.2 in the figure indicate liquid hydrogen and hydrogen gas, respectively.

[0022] The casing 10 is a hollow long member that includes a central large cylindrical portion 11 and large end plates 12 and 13 at respective ends. The casing 10 has a heat medium flowing therein. The large cylindrical portion 11 is a cylindrical long member having an inner diameter D1 and extending in the longitudinal direction (Y-direction). The large end plate 12 is a semi-elliptical end plate attached to the end portion of the large cylindrical portion 11 on the Y-direction minus side. The large end plate 13 is a semi-elliptical end plate attached to the end portion of the large cylindrical portion 11 on the Y-direction plus side. The large end plate 12 is provided with two openings 15a. Each opening 15a is connected to a respective end of a heat medium inlet header 15. The heat medium inlet header 15 is connected to a heat medium inlet pipe 16. The large end plate 13 is also provided with two openings 17a. Each opening 17a is connected to a heat medium outlet header 17. The heat medium outlet header 17 is connected to a heat medium outlet pipe 18.

[0023] The spiral tube 20 is a spirally wound tube with a diameter d. The spiral tube 20 has liquid hydrogen or hydrogen gas flowing therein. The spiral tube 20 includes an inner spiral tube 21 and an outer spiral tube 25. The inner spiral tube 21 is a spirally wound tube with a diameter d so as to have a winding inner diameter E1 and a winding outer diameter E2. Here, the winding outer diameter E2 is E1+2?d. The outer spiral tube 25 is also a spirally wound tube with a diameter d so as to have a winding outer diameter F2 and a winding inner diameter F1. Here, the winding inner diameter F1=F2?2?d. The winding outer diameter F2 of the outer spiral tube 25 is smaller than the inner diameter D1 of the large cylindrical portion 11 of the casing 10, and the winding inner diameter E1 of the inner spiral tube 21 is larger than the outer diameter D2 of a small cylindrical portion 31 of the spacer 30, which will be described later.

[0024] The inner spiral tube 21 is nested inside the winding inner diameter F1 of the outer spiral tube 25. The Y-direction plus side end portion of the inner spiral tube 21 and the Y-direction plus side end portion of the outer spiral tube 25 are connected to each other. The Y-direction minus side end portion of the inner spiral tube 21 is connected to a liquid hydrogen inlet pipe 22. The liquid hydrogen inlet pipe 22 is attached to the large end plate 12 of the casing 10 via a cylindrical coupling 27. The Y-direction minus side end portion of the outer spiral tube 25 is connected to a hydrogen gas outlet pipe 26. The hydrogen gas outlet pipe 26 is also attached to the large end plate 12 of the casing 10 via a cylindrical coupling 28, like the liquid hydrogen inlet pipe 22. In this manner, the inner spiral tube 21 and the outer spiral tube 25 communicate with each other to form the spiral tube 20, inside which liquid hydrogen or hydrogen gas flows.

[0025] The spacer 30 is a hollow closed cross-section member that extends in the longitudinal direction of the casing 10 and includes the central small cylindrical portion 31, and small end plates 32 and 33 at respective ends. The small cylindrical portion 31 is a cylindrical long member having an outer diameter D2 and extending in the longitudinal direction (Y-direction). The small end plate 32 is a hemispherical end plate attached to the end portion of the small cylindrical portion 31 on the Y-direction minus side. The small end plate 33 is a hemispherical end plate attached to the end portion of the small cylindrical portion 31 on the Y-direction plus side. The small end plate 32 is attached to the center of the large end plate 12 of the casing 10 with a connecting member 34 provided at the center. Also, the small end plate 33 is attached to the center of the large end plate 13 of the casing 10 with a connecting member 35 provided at the center. Thus, the spacer 30 is attached inside the casing 10 so as to be coaxial with the casing 10. The part between the inner surface of the large cylindrical portion 11 of the casing 10 and the outer surface of the small cylindrical portion 31 of the spacer 30 forms an annular channel 50 having a width W. The outer diameter D2 of the small cylindrical portion 31 is smaller than the winding inner diameter E1 of the inner spiral tube 21. Thus, the spacer 30 is disposed inside the winding inner diameter E1 of the inner spiral tube 21.

[0026] As shown in FIG. 2, a plurality of outer tube receivers 14 extending in the longitudinal direction (Y-direction) are attached to the inner surface of the large cylindrical portion 11 of the casing 10. A plurality of inner tube receivers 36 extending in the longitudinal direction are attached to the outer surface of the small cylindrical portion 31 of the spacer 30. Each outer tube receiver 14 is made of a round bar. Likewise, each inner tube receiver 36 is also made of a round bar.

[0027] Each outer tube receiver 14 is in point contact at points P with side surfaces on the winding outer diameter side of individual winding turns of the tube, the turns forming the outer spiral tube 25. The outer tube receiver 14 radially supports the surface on the winding outer diameter side of the outer spiral tube 25. Therefore, a gap S1 is provided between the surface on the winding outer diameter side of the outer spiral tube 25 and the inner surface of the large cylindrical portion 11. In addition, each inner tube receiver 36 is in point contact at points Q with side surfaces on the winding inner diameter side of individual winding turns of the tube, the turns forming the inner spiral tube 21. The inner tube receiver 36 radially supports the surface on the winding inner diameter side of the inner spiral tube 21. Therefore, a gap S2 is provided between the surface on the winding inner diameter side of the inner spiral tube 21 and the outer surface of the small cylindrical portion 31. In this manner, the spiral tube 20 is mounted in the annular channel 50 with gaps S1 and S2 respectively: between the outer spiral tube 25 and the inner surface of the large cylindrical portion 11; and between the inner spiral tube 21 and the outer surface of the small cylindrical portion 31.

[0028] The following describes the operation of the vaporizer 100 configured as above. In the following description, the heat medium to be used is LLC (long life coolant) or water, but it may be another liquid heat medium.

[0029] The liquid hydrogen, which has flowed into the inner spiral tube 21 from the liquid hydrogen inlet pipe 22, flows through the inner spiral tube 21 toward the Y-direction plus side. Then, the liquid hydrogen flows into the outer spiral tube 25 at the end portion on the Y-direction plus side, and flows through the outer spiral tube 25 toward the Y-direction minus side.

[0030] Meanwhile, the high-temperature LLC flows from the heat medium inlet pipe 16 through the heat medium inlet header 15 and flows into the casing 10 through the openings 15a provided in the casing 10. The LLC, which has flowed into the casing 10, flows toward the Y-direction plus side through the annular channel 50 having a width W, as indicated by an arrow 91 in FIG. 1.

[0031] Liquid hydrogen and LLC exchange heat through the inner spiral tube 21 and the outer spiral tube 25. The liquid hydrogen is then vaporized into hydrogen gas and flows out from the hydrogen gas outlet pipe 26. Meanwhile, the high-temperature LLC has a temperature drop due to heat exchange with liquid hydrogen, becomes a low-temperature LLC, flows from the openings 17a of the casing 10 through the heat medium outlet header 17, and then flows out from the heat medium outlet pipe 18.

[0032] The vaporizer 100 described above having the spacer 30 therein can cause the area of the channel, through which the heat medium flows, to be the cross-sectional area of the annular channel 50 that is smaller than the cross-sectional area of the casing 10. This makes it possible to increase the flow velocity of the heat medium inside the casing 10 and prevent the heat medium from freezing.

[0033] In addition, the vaporizer 100 has the spiral tube 20 that is mounted in the annular channel 50 with gaps S1 and S2 respectively: between the spiral tube 20 and the inner surface of the large cylindrical portion 11; and between the spiral tube 20 and the outer surface of the small cylindrical portion 31. Therefore, the LLC flows into the gaps S1 and S2, thereby improving the heat exchange efficiency and making the vaporizer 100 compact. Moreover, the smaller channel area of the annular channel 50 caused by the spiral tube 20 makes it possible to increase the flow velocity of the heat medium inside the annular channel 50, preventing the heat medium from freezing.

[0034] Furthermore, the gaps S1 and S2 prevent the large cylindrical portion 11 and the small cylindrical portion 31 from being in contact with the spiral tube 20, which has an extremely low temperature. Thereby, drastic temperature change of the casing 10 and the spacer 30 can be prevented.

[0035] Furthermore, the outer tube receiver 14 of the large cylindrical portion 11 and the inner tube receiver 36 of the small cylindrical portion 31 respectively support the outer spiral tube 25 and the inner spiral tube 21 by point contact. This reduces the contact area between: the casing 10 or the spacer 30; and the outer spiral tube 25 or the inner spiral tube 21, which spiral tubes have extremely low temperatures. This makes it possible to prevent the casing 10 or the spacer 30 from undergoing drastic temperature change.

[0036] In the above description, the spacer 30 is a hollow closed cross-section member extending in the longitudinal direction of the casing 10, but the spacer is not limited to this, so long as it restricts the flow of the heat medium inside the inner spiral tube 21. For example, the spacer may be a plate-like baffle plate provided inside the inner spiral tube 21. Alternatively, the spacer may be a spiral baffle plate, in the form of a flat plate spirally twisted, provided inside the inner spiral tube 21. This makes it possible to restrict the flow of the heat medium inside the inner spiral tube 21 and to increase the flow velocity of the heat medium in the other portions, thereby preventing the liquid heat medium from freezing.

[0037] According to research conducted by the inventors, in use of liquid LLC or water as a heat medium, when the flow velocity of the heat medium inside the casing 10 is 20 mm/s or more, the effect of preventing freezing of the heat medium begins to appear, and when the flow velocity is 26 mm/s or more, the effect of preventing freezing becomes remarkable. Therefore, when LLC or water is used as a heat medium and liquid hydrogen is vaporized by the vaporizer 100, the flow rate of a cooling water pump, through which LLC or water flows, may be increased to cause the flow velocity of LLC or water inside the casing 10 to be the above-described flow velocity.

[0038] Moreover, according to the research of the inventors, it is possible to prevent the heat medium from freezing in use of LLC or water as a heat medium, by setting the temperature difference between the temperature of the heat medium in the heat medium inlet pipe 16 and the temperature of the heat medium in the heat medium outlet pipe 18 to 10? C. or less. Therefore, when LLC or water is used as a heat medium and liquid hydrogen is vaporized by the vaporizer 100, the flow rate of the cooling water pump, through which LLC or water flows, may be increased to cause the temperature difference between the temperature of the heat medium in the heat medium inlet pipe 16 and the temperature of the heat medium in the heat medium outlet pipe 18 to be 10? C. or less.