JP2008180444A - Loop heat pipe - Google Patents

Abstract

To obtain a high heat exchange efficiency while making a loop heat pipe a flat and simple structure and making it thin and compact.
A loop heat pipe (1) includes an evaporator (3) that is cooled by using latent heat when a working fluid (5L) is vaporized, a steam pipe (9) through which a gas (5V) from the evaporator (3) moves, and the steam pipe (9). A condenser that dissipates and liquefies the gas 5V from the gas, and a liquid return pipe 13 that moves the working fluid 5L of the condenser to the evaporator 3. The evaporator 3 includes a bottom plate member 15 connected to the liquid return pipe 13, a lid member 17 connected to the steam pipe 9, and a flat plate-like wick 19 disposed between the bottom plate member 15 and the lid member 17. In addition, a groove portion 27 including a plurality of groove grooves 27A communicating with the steam pipe 9 is provided on a flat plate-like surface on the side in contact with the lid member 17, and communicated with the liquid return pipe 13 to reserve the hydraulic fluid 5L. And the wick 19 provided on the flat plate-like back surface on the side in contact with the bottom plate member 15.
[Selection] Figure 1

Description

  The present invention relates to a loop heat pipe, and more particularly to a loop heat pipe using an evaporator that can realize space saving and improvement in heat collection performance of a large area.

  Conventionally, an evaporator is used in, for example, LHP (loop heat pipe) or CPL (capillary pumped loop).

  Referring to FIG. 5, for example, the conventional LHP 101 has basically the same configuration as that of Patent Document 1, and an evaporator 103 that cools using latent heat when the working fluid vaporizes, and the evaporator The gas vaporized in 103 moves through the vapor pipe 105 and the condenser 107 (Condenser) that radiates and liquefies the gas, and the working liquid liquefied in the condenser 107 moves through the liquid return pipe 109. A reservoir unit 111 (or an accumulator, a CC (Compensation Chamber), etc.) that is reserved to supply the working liquid to the evaporator 103 and the working liquid returned from the liquid return pipe 109 are supplied to the inside of the evaporator 103. And a bayonet tube 113 to supply a single loop, and the evaporator 103 and the reservoir 111 are integrally formed. That.

  Also, an O-ring 115 for preventing backflow of hydraulic fluid is installed between the evaporator 103 and the reservoir unit 111 to prevent the gas vaporized by the evaporator 103 from returning to the reservoir unit 111. . Further, a working fluid is introduced into the LHP 101. Examples of the hydraulic fluid include alcohol, ammonia, and water. In the CPL, the evaporator 103 and the reservoir unit 111 are configured separately.

  In the LHP 101, when the evaporator 103 is heated by the heat generated in the surroundings, for example, water as a working fluid becomes steam in the evaporator 103, and the ambient temperature at this time is used to cool the ambient temperature. . Vapor generated in the evaporator 103 moves to the condenser 107 through the vapor pipe 105 and is dissipated in the condenser 107, whereby the vapor is returned to water. This water moves again to the reservoir 111 and the evaporator 103 via the liquid return pipe 109, and the above operation is repeated.

  6 and 7 together, the conventional evaporator 103 includes a cylindrical groove tube 117 having one end side opened and the other end side communicating with the steam tube 105 and closed, and the groove tube 117. And a wick 119 that contacts and inserts the inside of the cylindrical shape and supplies hydraulic fluid to the inside of the cylindrical shape.

  The groove tube 117 is provided with groove portions 121 on the inner peripheral surface of the groove tube 117 which are alternately uneven in the circumferential direction in a cross section perpendicular to the longitudinal direction of the groove tube 117 and extended in the longitudinal direction. ing. On the other hand, the outer peripheral surface of the wick 119 is in contact with the inner peripheral surface of the convex portion 121 </ b> B of the groove portion 121 of the groove tube 117, and the concave portion 121 </ b> A of the groove portion 121 serves as a steam flow path 123.

  The cylindrical interior of the wick 119 forms a liquid storage chamber 125 that communicates with the above-described reservoir 111 and whose front end is closed. In addition, since the bayonet tube 113 communicating with the liquid return pipe 109 is inserted through the reservoir 111 to a little before the front end of the liquid storage chamber 125, the water returned from the liquid return pipe 109 A liquid storage chamber 125 is supplied from the front end of the net tube 113. This water is turned 180 ° from the front end of the bayonet tube 113, passes between the liquid reservoir chamber 125 and the bayonet tube 113 and fills the liquid reservoir chamber 125, and is retained in the reservoir unit 111.

  As the wick 119, for example, a porous sintered metal body, metal fiber, glass fiber or the like is used.

Therefore, when the groove tube 117 is heated by the heat around the evaporator 103, the heat of the groove tube 117 is conducted from the contact portion with the inner peripheral surface of the convex portion 121B of the groove portion 121 to the wick 119, and the wick 119 Is heated. As a result, water that has penetrated from the liquid storage chamber 125 into the wick 119 is heated to become steam, and moves to the steam pipe 105 through the groove portion 121 of the groove pipe 117, that is, the steam flow path 123, as described above. It will be.
JP 2002-174492 A

  As shown in FIG. 5, the LHP 101 includes an evaporator 103, which has a cylindrical groove tube 117 and a cylindrical wick 119 that is inserted into contact with the inside of the cylindrical shape of the groove tube 117. Therefore, there is a problem in that the outer shape becomes a cylindrical shape, resulting in a large size and a large space.

  In addition, the size of the reservoir unit 111 greatly affects the cooling performance of the entire system. Since the capacity of the reservoir unit 111 tends to be increased by increasing the outer diameter of the reservoir unit 111, the LHP 101 is In the device to be mounted, there is a problem that a space for storing the reservoir 111 is particularly large in three dimensions.

  In other words, since the cylindrically shaped evaporator tube 103 and the wick 119 have a three-dimensional structure, the evaporator 103 having a cylindrical shape has a high heat density and is weak in a large area. There was a problem of being lowered.

  In particular, notebook PCs and other electronic devices that use LHP tend to be thinner and smaller in recent years, so that the heat generated in these electronic devices can be collected more efficiently and dissipated to the outside. There was a need for an LHP to do.

In order to achieve the problem to be solved by the invention, a loop heat pipe of the invention includes an evaporator that cools using latent heat generated when the working fluid is vaporized, and a gas vaporized by the evaporator moves. In a loop heat pipe composed of a steam pipe, a condenser that radiates and liquefies the gas from the steam pipe, and a liquid return pipe that moves the working liquid liquefied in the condenser to the evaporator,
The evaporator is a bottom plate member connected to the liquid return pipe, a lid member connected to the steam pipe, and a flat plate wick disposed between the bottom plate member and the lid member, A groove portion comprising a plurality of groove grooves communicating with the steam pipe is provided on a flat plate-like surface on the side in contact with the lid member, and a reservoir portion communicating with the liquid return pipe and retaining the working fluid is provided with the bottom plate member. And a wick provided on the flat plate-like back surface on the contact side.

  In the loop heat pipe of the present invention, it is preferable that in the loop heat pipe, the reservoir portion is constituted by a plurality of flow path reservoir grooves provided on the back surface of the wick.

  In the loop heat pipe of the present invention, it is preferable that a backflow prevention mechanism for gas or hydraulic fluid is provided on the outer periphery of the wick.

  Moreover, it is preferable that the loop heat pipe of this invention is a structure in which the said backflow prevention mechanism does not form the said groove part over the outer peripheral part of the surface of the said wick, or a back surface in the said loop heat pipe.

  Further, the loop heat pipe according to the present invention is configured such that, in the loop heat pipe, the backflow prevention mechanism is formed so that the thickness of the wick is slightly thicker than an interval formed between the bottom plate member and the lid member. Preferably there is.

  In the loop heat pipe of the present invention, it is preferable that the backflow prevention mechanism has a configuration in which an outer peripheral portion of the wick is formed slightly thicker than regions of the groove and the reservoir portion.

  Further, the loop heat pipe of the present invention is the loop heat pipe, in the loop heat pipe, on the inner surface of the lid member or the bottom plate member in contact with the outer peripheral portion of the wick, on the region of the lid member in contact with the groove portion or the bottom plate in contact with the reservoir portion It is preferable to provide a backflow preventing convex portion that is slightly higher than the region of the member.

  Moreover, it is preferable that the loop heat pipe of this invention is a structure which the edge part of the said liquid return pipe protrudes from a baseplate member, and is inserted in the inside of the said reservoir part in the said loop heat pipe.

  As can be understood from the means for solving the problems as described above, according to the present invention, since the groove groove and the reservoir portion are provided on the back surface of the flat wick, the evaporator is formed in a flat plate shape. Space saving can be achieved by realizing a reduction in thickness and size. Further, by making the evaporator flat, the groove groove and the reservoir region are enlarged on the plane, so that it is possible to improve the heat collection efficiency and the water absorption efficiency (heat exchange efficiency). Therefore, since the above evaporator is used, this loop heat pipe is much smaller than conventional evaporators and can be used for various devices. And cooling with high water absorption efficiency (heat exchange efficiency) can be performed.

  Embodiments of the present invention will be described below with reference to the drawings.

  With reference to FIG. 1 thru | or FIG. 3, the evaporator 3 which concerns on this embodiment is used for the loop heat pipe 1 (LHP) which concerns on this embodiment.

  The evaporator 3 has a function of cooling using latent heat when the working fluid 5L is vaporized, and a reservoir unit 7 [or an accumulator, a CC (Compensation Chamber), etc. for holding the working fluid 5L supplied therein. ].

  The LHP 1 radiates and liquefies the evaporator 3, the vapor pipe 9 (Vapor Line) that moves the gas 5 V vaporized by the evaporator 3, and the gas 5 V that has moved through the vapor pipe 9. A system comprising a condenser 11 and a liquid return pipe 13 (Liquid Line) that moves 5 L of hydraulic fluid liquefied by the condenser 11 to the evaporator 3 forms a loop. Yes.

  Note that 5 L of hydraulic fluid is introduced into the LHP 1. Examples of the hydraulic fluid 5L include alcohol, ammonia, and water. In this embodiment, the hydraulic fluid 5L is water from the viewpoint of the global environment. In FIG. 1, the flow direction of the water that is the hydraulic fluid 5L is indicated by a solid arrow, and the flow direction of water vapor that is the gas 5V obtained by vaporizing the hydraulic fluid 5L is indicated by a dotted arrow.

  That is, in the LHP 1 described above, when the evaporator 3 is heated by the heat generated in the surroundings, the water that is the hydraulic fluid 5L becomes vapor in the evaporator 3, and the ambient temperature at this time is used to cool the ambient temperature. To do. The steam generated inside the evaporator 3 moves to the condenser 11 through the steam pipe 9 and is dissipated in the condenser 11 to return the steam to water. This water moves again through the liquid return pipe 13 to the reservoir section 7 in the evaporator 3 and repeats the above operation. Therefore, LHP1 uses latent heat and has a high heat transport capability without an external power source. Further, the piping of the steam pipe 9 and the liquid return pipe 13 is free, and the heat transmission direction behaves like a diode in one direction from the evaporator 3 to the condenser 11.

  Referring to FIGS. 1 and 2, the evaporator 3 is configured by combining a bottom plate member 15, a lid member 17, and a wick 19, and incorporates a reservoir portion 7.

  The bottom plate member 15 is basically flat and is connected to the liquid return pipe 13. In this embodiment, it is a thin container shape having a substantially circular opening 15A and having a U-shaped cross section at the bottom 15B and the side wall 15C. Further, a liquid return pipe hole 21 for inserting the liquid return pipe 13 is provided at a substantially central position of the bottom portion 15B.

  The lid member 17 is basically flat and is connected to the steam pipe 9. In this embodiment, a substantially circular flat plate shape is formed so as to close the opening 15 </ b> A of the bottom plate member 15. Further, a steam pipe hole 23 for inserting the steam pipe 9 is provided at the outer peripheral portion of the lid member 17. Accordingly, a space 25 is formed between the bottom plate member 15 and the lid member 17.

  The wick 19 basically has a flat plate shape disposed between the bottom plate member 15 and the lid member 17. In this embodiment, it is a thin plate having a substantially circular shape, and is disposed so as to fit perfectly in the space 25 between the bottom plate member 15 and the lid member 17.

  In the present embodiment, the wick 19 is made of a polymer material in order to reduce the weight. As this polymer, for example, a sintered product of polyethylene powder having a diameter of 10 to 20 μm is used. In such a polymer, since each powder has a hydrophilic group, a + α pumping force is applied to the wettability and the surface tension. Becomes larger.

  Further, on the flat surface of the wick 19 on the side in contact with the lid member 17, a groove portion 27 including a plurality of groove grooves communicating with the steam pipe 9 is provided. In this embodiment, as shown in FIG. 1 and FIG. 2, the groove portion 27 is formed in a portion perpendicular to the surface of the wick 19 at a portion other than the outer peripheral portion 29 of the flat surface of the wick 19. For example, the concave portions 27 </ b> A and the convex portions 27 </ b> B as grooves form an uneven shape in the width direction of the wick 19, and the uneven shape is extended in one direction of the wick 19. Further, the outer peripheral portion 29 of the flat surface of the wick 19 is provided with the groove-free portion 31 without forming the groove portion 27 over the entire area.

  In this embodiment, the number of the recesses 27A (groove grooves) is large, and the cross-sectional shape of the recesses 27A is a square shape. However, other cross-sectional shapes such as a V-groove shape may be used. The number and the cross-sectional shape are not limited. That is, the size of the cross-sectional area of the concave portion 27A can be variously set by changing the number, shape, and the like of the concave portion 27A of the groove portion 27.

  A circumferential steam channel 33 communicating with each recess 27A of the groove portion 27 is provided in the circumferential direction at the boundary between the groove portion 27 and the outer peripheral portion. That is, the steam in each recess 27 </ b> A flows to the circumferential steam flow path 33.

  Further, the groove portion 27 has one or more steam pressure adjusting grooves 35 communicating with the recesses 27A (groove grooves) in order to control the steam pressure difference between the groove grooves. 27 is provided in a direction orthogonal to the concave portion 27 </ b> A (groove groove), and each of the steam pressure adjusting grooves 35 communicates with the circumferential steam flow path 33. In this embodiment, as shown in FIG. 2, two vapor pressure adjusting grooves 35 are provided. Further, it is desirable that each of the steam pressure adjusting grooves 35 is larger than each of the recesses 27A (groove grooves) from the viewpoint of efficiently spreading the steam.

  It should be noted that the numerous recesses 27A (groove grooves) described above are arranged in parallel in one direction on the surface of the wick 19, but may extend radially from the center of the surface of the wick 19 or be randomly arranged. It may be. However, each concave portion 27 </ b> A is configured to communicate with the vapor pressure adjusting groove 35 and the circumferential steam flow path 33.

  In addition, a reservoir portion 7 that communicates with the liquid return pipe 13 and holds the hydraulic fluid 5L is provided on the flat plate-like back surface of the wick 19 that contacts the bottom plate member 15. In this embodiment, as shown in FIGS. 1 and 2, the reservoir portion 7 is composed of a plurality of reservoir grooves 39 provided in a portion excluding the outer peripheral portion 37 of the flat plate-like back surface of the wick 19. Yes. For example, a liquid introduction reservoir groove 39A for inserting the liquid return pipe 13 is provided at a substantially central portion of the flat plate-like back surface of the wick 19, and a plurality of circumferential reservoir grooves 39B are formed as the liquid introduction reservoir grooves. It is long in the circumferential direction so as to surround the periphery of 39A several times. Further, the plurality of circumferential reservoir grooves 39B communicate with each other by bypass reservoir grooves 39C at appropriate locations. Thereby, the plurality of reservoir grooves 39 are stretched over the entire flat plate-like back surface of the wick 19, and the hydraulic fluid 5 </ b> L spreads over almost the entire back surface of the wick 19.

  The plurality of reservoir grooves 39 are not limited to the above-described arrangement, and may be radial, parallel, or other arrangements as long as the hydraulic fluid 5L spreads over substantially the entire back surface of the wick 19. Further, as described above, it is desirable that each reservoir groove 39 communicates with the bypass reservoir groove 39 on the way, so that the hydraulic fluid 5L can be distributed evenly throughout.

  The reservoir portion 7 may basically be provided with a single recess in a region covering almost the entire portion of the wick 19 except for the outer peripheral portion 37 on the flat plate-like back surface. By comprising the groove 39, it is difficult to be affected by the inclination of the evaporator 3 and the like, and there is an effect of performing stable heat collection.

  Therefore, as the evaporator 3 of this embodiment, as shown in FIGS. 1 and 2, the wick 19 is inserted into the bottom plate member 15, and then the opening 15 </ b> A of the bottom plate member 15 is used as a lid member. 17 and the wick 19 is accommodated, and the bottom plate member 15 and the lid member 17 are closed with brazing (or soldering). Alternatively, the bottom plate member 15, the wick 19, and the lid member 17 can be fixed by pressing the outer peripheral portions of the bottom plate member 15 and the lid member 17 from the outside with a fastener (not shown).

  As described above, when the bottom plate member 15, the wick 19, and the lid member 17 are fixed, on the surface side of the lid member 17 and the wick 19, a steam flow is provided between the recess 27 </ b> A and the inner surface of the lid member 17 in the groove portion 27. A passage 43 is formed, and a steam pressure adjusting groove 35 and a circumferential steam passage 33 are also formed. On the other hand, on the bottom portion 15 </ b> B of the bottom plate member 15 and the back surface side of the wick 19, a liquid flow path 41 is formed by the bottom surface of the bottom plate member 15 and each reservoir groove 39 in the reservoir portion 7.

  Further, the liquid return pipe 13 is inserted into the liquid return pipe hole 21 of the bottom plate member 15, and into the liquid introduction reservoir groove 39 </ b> A at the substantially central part of the flat plate-like back surface of the wick 19. After being inserted to the height, it is connected to the liquid return pipe hole 21 by soldering (or soldering). On the other hand, the steam pipe 9 is connected to the steam pipe hole 23 of the lid member 17 by brazing (or soldering). At this time, the steam pipe 9 is in a position communicating with the circumferential-side steam flow path 33.

  Further, in the outer peripheral portion 29 of the flat surface of the wick 19 described above, the groove-less portion 31 becomes water vapor by increasing the surface pressure by bringing the gap at the interface between the groove-free portion 31 and the lid member 17 into small contact. It becomes the structure of the backflow prevention mechanism 45 of (gas 5V).

  The margin of the gap at the interface between the groove-free portion 31 and the lid member 17 is determined by the difference between the vapor pressure generated by heating of the evaporator 3 and the vapor pressure in the reservoir portion 7 and the surface tension of the hydraulic fluid 5L. Since a polymer body of polyethylene is used as the material of the wick 19, it is installed without a gap due to the elasticity of polyethylene. Therefore, the surface pressure at the interface between the non-groove portion 31 and the lid member 17 can be kept high.

  This point will be described in more detail. It is desirable that the surface pressure at the interface between the lid member 17 and the outer peripheral surface of the non-grooved portion 31 of the wick 19 is set to be equal to or higher than the vapor pressure generated in the groove portion 27.

  For example, by making the thickness of the wick 19 slightly thicker than the height dimension of the space 25 formed by the bottom plate member 15 and the lid member 17 (the distance between the bottom plate member 15 and the lid member 17), Since the surface pressure of the interface can be increased, the backflow of water vapor generated in the groove portion 27 can be suppressed.

  Moreover, as the backflow prevention mechanism 45 of other embodiment, the backflow of water vapor | steam can be prevented by making the thickness of the outer peripheral part 29 slightly thicker than the thickness of the area | region of the groove part 27. FIG.

  Further, as a backflow prevention mechanism 45 of another embodiment, as shown in FIG. 1, an O-ring groove 47 is provided on the outer peripheral portion 29 of the surface of the wick 19 as shown in FIG. The reverse flow of water vapor can be suppressed by the O-ring 49 attached to the O-ring groove 47. In this embodiment, one O-ring 49 is provided, but two or more may be used.

  In addition, a backflow prevention mechanism 51 for the hydraulic fluid 5L is provided on the outer peripheral portion 37 of the flat plate-like back surface of the wick 19 described above. As the backflow prevention mechanism 51, for example, as shown in FIG. 2B, the reservoir groove 39 is not provided over the entire outer peripheral portion 37, and the wick 19 in the outer peripheral portion 37 is not provided. By increasing the length L in the radial direction from the center, the backflow of the hydraulic fluid 5L can be prevented. More specifically, the contact area between the outer peripheral portion 37 on the back surface of the wick 19 and the bottom portion 15B of the bottom plate member 15, that is, the length L of the contact portion, cannot cause a phase change of the hydraulic fluid 5L due to the influence of heat from the heating portion. By being sufficiently long with respect to the length, the backflow of the hydraulic fluid 5L can be prevented.

  Alternatively, similarly to the backflow prevention mechanism 45 described above, the thickness of the wick 19 is slightly smaller than the height of the space 25 formed by the bottom plate member 15 and the lid member 17 (the distance between the bottom plate member 15 and the lid member 17). By making it thick, the backflow of the hydraulic fluid 5L can be prevented. Alternatively, the backflow of the hydraulic fluid 5L can be prevented by making the thickness of the outer peripheral portion 37 slightly thicker than the thickness of the reservoir portion 7.

  Further, as the backflow prevention mechanism 51 of the other embodiment, as shown in FIG. 1, an O-ring groove 53 is provided on the outer peripheral portion 37 on the back surface of the wick 19 as shown in FIG. The backflow of the hydraulic fluid 5L can be suppressed by the O-ring 55 attached to the O-ring groove 53. In this embodiment, two O-rings 55 are provided, but there may be one or three or more.

  Further, as shown in FIG. 4, as the backflow prevention mechanisms 45 and 51 of other embodiments, one of the lid member 17 and the bottom plate member 15 that contacts the outer peripheral portions 29 and 37 of the wick 19, Alternatively, the backflow prevention convex portions 57 and 59 that are slightly higher than the region of the lid member 17 in contact with the groove portion 27 or the region of the bottom plate member 15 in contact with the reservoir portion 7 can be provided on both inner surfaces.

  Thus, when the bottom plate member 15, the wick 19 and the lid member 17 are fixed as described above, since the polymer body of polyethylene is used as the material of the wick 19, the above-described backflow preventing convex portions 57 and 59 are provided. Since the wick 19 is pressed more strongly than the portion of the other region, it is installed without a gap due to the elasticity of polyethylene, and the surface pressure at the interface can be kept high. As a result, the backflow of water vapor or hydraulic fluid 5L can be prevented.

  In the above-described embodiment, the bottom plate member 15 has a container shape for housing the wick 19. However, as another embodiment, the bottom plate member 15 and the lid member 17 are formed in a simple flat plate shape, and A configuration in which the wick 19 is sandwiched between the bottom plate member 15 and the lid member 17 may be employed. In this case, the bottom plate member 15, the wick 19 and the lid member 17 are fixed by pressing the outer peripheral portions of the bottom plate member 15 and the lid member 17 from the outside with a fastener (not shown).

  The operation of the LHP 1 of this embodiment will be described with the above configuration. As shown in FIG. 3, when the lid member 17 of the evaporator 3 is heated by ambient heat, the lid member 17 and the wick 19 The heat of the lid member 17 is efficiently conducted from the contact surface of the groove portion 27 and the wick 19 is heated.

  On the other hand, the water in the reservoir portion 7 composed of a plurality of reservoir grooves 39 is improved in wettability and surface because each powder of the polyethylene polymer of the wick 19 has a hydrophilic group as described above. A pumping force of + α is applied to the tension and a vacuum is drawn. Since the water inside the wick 19 that has permeated by this evacuation has a reduced pressure, when heated, the water boils at a low boiling point and becomes steam. The ambient temperature is cooled by the latent heat when water becomes steam.

  As described above, the steam is pushed out by the force with which water is evacuated into the polymer body of the wick 19, moves in the polymer body of the wick 19, and flows from the surface of the recess 27 </ b> A of the groove portion 27 to the steam channel 43. It will be.

  Further, the steam in the steam channel 43 flows to the circumferential steam channel 33 through the two steam pressure adjusting grooves 35 communicating with the respective recesses 27 </ b> A (groove grooves). At this time, since the two steam pressure adjusting grooves 35 are provided, the steam pressure difference of each recess 27A (groove groove) is easily controlled, so that the steam flows efficiently in a stable state. .

  Further, the steam in the circumferential steam flow path 33 moves to the condenser 11 through the steam pipe 9 as described above, and the heat is radiated by the condenser 11 to return the steam to water. This water returns to the reservoir section 7 inside the evaporator 3 through the liquid return pipe 13 and is held again. At this time, since the liquid introduction reservoir groove 39A is provided at the substantially central portion of the wick 19, the water in the liquid return pipe 13 flows from the liquid introduction reservoir groove 39A at the substantially central portion of the wick 19 to the bypass reservoir groove 39C. Thus, it is possible to efficiently spread almost the entire back surface of the wick 19 to the multiple circumferential reservoir grooves 39B on the outer peripheral side, so that stable heat exchange can be performed. Further, as described above, since the reservoir section 7 is constituted by the plurality of reservoir grooves 39, it is difficult to be affected by the inclination of the evaporator 3, and stable heat collection can be performed. Then, the above operation is repeated.

  As described above, the evaporator 3 according to this embodiment is a device that cools by depriving heat using, for example, water as steam as the hydraulic fluid 5L, and the cooling capacity of the evaporator 3 that uses latent heat as described above is as follows. Since it is obtained from the product of the evaporation rate of water per unit area and the latent heat of evaporation, the cooling capacity increases as the contact state between the wick 19 and the lid member 17 is better and the heat conduction efficiency is higher. In this respect, the gap at the interface between the groove portion 27 and the lid member 17 is in small contact, and further, for example, by using a polyethylene polymer as the material of the wick 19, it is installed without a gap due to the elasticity of polyethylene. Therefore, the heat conduction efficiency between the wick 19 and the lid member 17 is high.

  Further, the water vapor generated by heating the groove portion 27 should not flow back to the reservoir portion 7, and the heat of the groove portion 27 is conducted to the reservoir portion 7 through the lid member 17 and is transferred to the reservoir portion 7. The water inside should not change to water vapor.

  In this respect, in this embodiment, as the backflow prevention mechanism 45, the groove portion 27 and the non-grooved portion 31 of the outer peripheral portion 29 are provided on the surface of the wick 19, so that the groove-less portion is simple in structure. Thus, the reverse flow of the steam generated in the groove portion 27 can be prevented. Moreover, as described above, the contact state with the lid member 17 is set without gaps due to the elasticity of the polyethylene of the wick 19, so that the surface pressure at the interface between the non-groove portion 31 and the lid member 17 is kept high. It will surely prevent the backflow of steam.

  In particular, by making the thickness of the wick 19 slightly thicker than the height of the space 25 formed by the bottom plate member 15 and the lid member 17, the outer peripheral surface of the groove-free portion 31 of the lid member 17 and the wick 19. Can be set to be equal to or higher than the vapor pressure generated in the groove portion 27, so that it is possible to reliably prevent the backflow of the vapor.

  Further, the reverse flow of water vapor can be suppressed by the O-ring 49 provided on the outer peripheral portion 29 of the surface of the wick 19 over the entire circumference.

  Moreover, since the various backflow prevention mechanisms 51 are provided on the outer peripheral portion 37 on the back surface of the wick 19 as described above, the backflow of the hydraulic fluid 5L can be reliably prevented. In addition, since the operation | movement and effect of various backflow prevention mechanisms 51 are as having mentioned above, description is abbreviate | omitted.

  Further, since the end of the liquid return pipe 13 is inserted into the liquid introduction reservoir groove 39A constituting the reservoir section 7 to a height that is almost ½ of the depth thereof, the plurality of reservoir grooves 39 of the reservoir section 7; That is, the height of the water surface inside the plurality of circumferential reservoir grooves 39B that surround the liquid introduction reservoir groove 39A several times and the bypass reservoir grooves 39C that communicate with each circumferential reservoir groove 39B is determined by the respective reservoir grooves 39A, A space 61 is formed above each reservoir groove 39A, 39B, 39C by being approximately half the depth of 39B, 39C. This space 61 becomes a steam space for a steam pressure difference with the steam pipe 9.

  Further, the evaporator 3 of this embodiment can be made extremely thin because the wick 19 is flat, and the groove portion 27 is provided on the front surface of the wick 19 and the reservoir portion 7 is provided on the back surface. It is not a cylindrical shape requiring a large space like an evaporator, and it is not necessary to provide a member such as a bayonet tube, and the number of constituent members can be reduced. As a result, the evaporator 3 is inexpensive and can be reduced in thickness and size to save space, and the area of the groove part 27 and the area of the reservoir part 7 are large on a plane, so that the heat collection efficiency is high. In addition, the water absorption efficiency (heat exchange efficiency) can be improved.

  In addition, since the reservoir unit 7 is housed inside the evaporator 3, the LHP 1 using the evaporator 3 is much more compact than the LHP 1 provided with the conventional evaporator and the reservoir unit 7 separately. Can be size.

  Therefore, the LHP 1 using the evaporator 3 according to this embodiment is used for cooling the heat generated by, for example, OA devices such as notebook computers, digital home appliances, automobile dashboards, and various other devices. Cooling with high heat exchange efficiency can be performed while being thin and compact.

It is a schematic sectional drawing of the evaporator of embodiment of this invention. (A) is a schematic exploded perspective view of the evaporator of the embodiment of the present invention, and (B) is a schematic perspective view seen from the back surface of the wick. 1 is a schematic front view of a loop heat pipe according to an embodiment of the present invention. It is a fragmentary sectional view showing the backflow prevention mechanism of other embodiments. It is a schematic front view of the conventional loop heat pipe. It is a schematic perspective view containing the principal part cross section of the conventional evaporator. It is sectional drawing of the arrow VII-VII line of FIG.

Explanation of symbols

1 Loop heat pipe (LHP)
3 Evaporator 5L Working fluid (liquid)
5V gas (vaporized hydraulic fluid)
7 Reservoir section 9 Steam pipe 11 Condenser 13 Liquid return pipe 15 Bottom plate member 17 Lid member 19 Wick 21 Liquid return pipe hole section 23 Steam pipe hole section 25 Space 27 Groove section 27A Recess (groove groove)
27B Convex part 29 Outer peripheral part (on the wick surface side)
31 No-groove portion 33 Circumferential side steam passage 35 Steam pressure adjusting groove 37 Outer peripheral portion (on the back side of the wick)
39 Reservoir groove 39A Liquid introduction reservoir groove 39B Circumferential reservoir groove 39C Bypass reservoir groove 41 Liquid flow path 43 Steam flow path 45 Backflow prevention mechanism 49 O-ring 51 Backflow prevention mechanism 55 O-ring 57 Backflow prevention convex part 59 Backflow prevention Convex part 61 space

Claims (8)

An evaporator that cools using the latent heat generated when the hydraulic fluid is vaporized, a vapor pipe that moves the gas vaporized in the evaporator, a condenser that radiates and liquefies the gas from the vapor pipe, and this In a loop heat pipe composed of a liquid return pipe in which the working liquid liquefied in the condenser moves to the evaporator,
The evaporator is a bottom plate member connected to the liquid return pipe, a lid member connected to the steam pipe, and a flat plate wick disposed between the bottom plate member and the lid member, A groove portion comprising a plurality of groove grooves communicating with the steam pipe is provided on a flat plate-like surface on the side in contact with the lid member, and a reservoir portion communicating with the liquid return pipe and retaining the working fluid is provided with the bottom plate member. A loop heat pipe comprising: a wick provided on a flat plate-like back surface on the contact side.   The loop heat pipe according to claim 1, wherein the reservoir section includes a plurality of flow path reservoir grooves provided on a back surface of the wick.   The loop heat pipe according to claim 1 or 2, wherein a backflow prevention mechanism for gas or hydraulic fluid is provided on an outer peripheral portion of the wick.   The loop heat pipe according to claim 3, wherein the backflow prevention mechanism is configured not to form the groove portion over the entire outer peripheral portion of the front surface or the back surface of the wick.   The loop heat pipe according to claim 3, wherein the backflow prevention mechanism has a structure in which the thickness of the wick is formed slightly thicker than an interval formed between the bottom plate member and the lid member.   The loop heat pipe according to claim 3, wherein the backflow prevention mechanism has a configuration in which an outer peripheral portion of the wick is formed to be slightly thicker than regions of the groove and the reservoir portion.   On the inner surface of the lid member or bottom plate member in contact with the outer peripheral portion of the wick, a backflow prevention convex portion is provided that is slightly higher than the lid member region in contact with the groove portion or the bottom plate member region in contact with the reservoir portion. The loop heat pipe according to claim 1 or 2, characterized by the above.   The loop heat pipe according to claim 1, 2, 3, or 7, wherein an end portion of the liquid return pipe protrudes from a bottom plate member and is inserted into the reservoir portion.

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