JP2010054122A - Variable conductance heat pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide energy saving, to shorten a time from operation starting until a temperature of a cooling reception object is brought into a stationary state, and to provide the stable operation of the cooling reception object from immediately after operation starting in cooling the cooling reception object by using a variable conductance heat pipe. <P>SOLUTION: In the variable conductance heat pipe, a working fluid 6 and a non-condensible gas 8 are sealed in an airtight container 1 having a heat receiving part 2 and a heat dissipation part 4. The cooling reception object 9 is provided in the heat receiving part 2, and a heating value is applied to the heat receiving part during the standby of the cooling reception object 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable conductance heat pipe for maintaining a device temperature during non-operation at an arbitrary temperature with power saving.

  In order to obtain a desired function, a projection device, a printing device, and the like have to set the temperature of a main part such as a light source to an appropriate temperature. Temperature control devices for maintaining an appropriate temperature include a heater temperature controller that adjusts the temperature by heating the heater (hereinafter referred to as temperature control), a heat pump temperature controller that adjusts the temperature by heater heating or heat pump heating and heat pump cooling, and Peltier. There is a Peltier element type temperature controller that uses the effect to control the temperature by current control or current reversal. When there is a difference between the main part temperature during non-operation and the main part set temperature during operation when the above equipment is operating, the main part temperature is adjusted to the set temperature with the above temperature controller after turning on the equipment. Therefore, time (waiting time) required for temperature control occurs. The larger the temperature difference, the longer the waiting time and the convenience for the user is impaired. For this reason, some devices have been devised to operate the temperature controller in advance even during non-operation to control the temperature in advance to shorten the standby time.

Furthermore, in the image forming apparatus, power saving is realized by detecting the time during which the state without a request from the user continues, and changing the operation mode and the set heating temperature, and promptly responding to the request from the user. Some of them allow for a smooth output. (For example, Patent Document 1),
Japanese Patent Laying-Open No. 2005-49621 (page 13, FIG. 1)

  In an apparatus having an electronic device that requires temperature control, the temperature of the electronic device must always be kept close to the set temperature during operation in order to enable quick output in response to a request from the user. Although it is desirable, if the temperature of the electronic device is always maintained, a large amount of power is required and wasteful power is consumed. Therefore, in the image forming apparatus disclosed in Patent Document 1, the time during which the user's request is not being detected is detected, the operation mode is changed, the set heating temperature of the electronic device is lowered, and the like. There are also efforts to reduce power consumption. However, this method requires a device that detects input from the user and a control mechanism corresponding to the device, so that additional power is required for these controls, as well as heat dissipation from a radiator for electronic devices. Since the temperature is adjusted (heated) to the set temperature in parallel, the power consumption reduction effect is not so high.

  There is also a method to increase the temperature control speed up to the set temperature by using a high performance heating / cooling device together, but it requires advanced control with a short response time and is difficult to apply to small devices. .

  In the variable conductance heat pipe in which a working fluid and a non-condensable gas are sealed in a sealed container having a heat receiving portion and a heat radiating portion, heat is given to the heat receiving portion during standby operation.

  According to the present invention, the variable conductance heat pipe can be operated as an adiabatic heat pipe with small power by heat input to the heat receiving section, and the temperature of the heat receiving section depends on the amount of non-condensable gas sealed in the variable conductance heat pipe. Can be set to an arbitrary temperature, and the temperature of the cooled object provided in the heat receiving section can be easily adjusted to an arbitrary temperature.

Embodiment 1 FIG.
FIG. 1 is a sectional view showing a variable conductance heat pipe according to Embodiment 1 of the present invention. In FIG. 1, a heat receiving part 2 (evaporating part), a heat insulating part 3 (transporting part), a heat radiating part 4 (condensing part), and a non-condensable gas reservoir part 5 are formed from the end of the sealed container 1. 1, a variable conductance heat pipe 20 in which a working fluid (liquid 6 and its vapor 7) and a non-condensable gas 8 are sealed is provided with a heater 40 and a body 9 to be cooled in the heat receiving section 2 thereof.

  Next, the operation of the variable conductance heat pipe of the present invention will be described. When the cooled object 9 operates to obtain a desired function of the cooled object 9, heat is generated inside the cooled object 9, and the temperature of the cooled object 9 rises. The heat receiving section 2 is in contact with the cooled body 9 and the heat radiating section 4 is in contact with the cooling heat source 10, whereby heat is transferred from the higher temperature cooled body 9 to the heat receiving section 2. The heat is further transferred to the liquid 6 in the heat receiving section 2, and the liquid 6 absorbs heat in the form of latent heat and evaporates or boils to generate a vapor 7. The steam 7 or the steam 7 and the liquid 8 flow into the heat radiating part 4 through the heat insulating part 3, and the steam 7 condenses, releases the latent heat held by the steam 7 to the heat radiating part 4, and releases the released heat to the heat radiating part. The heat is radiated from 4 to the cooler heat source 10 having a lower temperature. At this time, the condensate (liquid 6) generated by condensing the vapor 7 is recirculated from the heat radiating unit 4 to the heat receiving unit 2 through the heat insulating unit 3 by gravity or capillary force. Due to the circulation of the vapor 7 and the liquid 6, the heat generated in the cooled object 9 is continuously transmitted (exhausted heat) to the cold heat source 10.

  On the other hand, the non-condensable gas 8 sealed in the sealed container 1 passes through the heat insulating part 3 and the heat radiating part 4 along with the movement of the vapor 7 or the vapor 7 and the liquid 8, and then the non-condensable gas reservoir 5 or the non-condensable gas. It is moved to the heat radiating part 4 on the side of the reservoir 5 and accumulated and stagnated. When the non-condensable gas 8 stagnates, the vapor 7 hardly enters the non-condensable gas 8, and forms an interface 11 between the vapor 7 and the non-condensable gas 8. When the vapor 7 continuously pushes the non-condensable gas 8, the interface 11 moves, and when the pressure of the vapor 7 and the non-condensable gas 8 reaches equilibrium, the movement of the interface 11 stops and the position is stabilized. . Therefore, (1) when the interface 11 is located in the non-condensable gas reservoir 5, the vapor 7 is condensed over the entire heat dissipating part 4, so that 100% heat dissipating ability is obtained, and (2) the interface 11 is located within the heat dissipating part 4. Then, since the area (heat radiation area) where the steam 7 condenses decreases, the heat radiation capacity decreases (0 <heat radiation capacity <100% variable). (3) When the interface 11 is located in the heat insulating part 3 or the heat receiving part 2, heat insulation is performed. (Heat dissipation capacity 0%). However, since heat is partially transferred due to heat conduction that travels through the wall of the hermetic container 1, there is actually a slight ability to dissipate heat.

  The above is the operation principle of the variable conductance heat pipe 20, and the temperature of the cooled object 9 is adjusted by the expansion / contraction of the non-condensable gas 8 by the operation of the cooled object 9, and is maintained at an arbitrary set temperature. However, when the operation of the cooled object 9 stops, the generation of the steam 7 stops, the non-condensable gas reservoir 5, the heat radiating part 4, the heat insulating part 3, the heat receiving part 2 and then the cooled object 9 are cooled. It will fall to the temperature equivalent to the cold heat source 10. In this state, when the cooled object 9 operates again, a delay time (waiting time) occurs until the temperature of the cooled object 9 reaches the set temperature. Therefore, in the present invention, the amount of heat generated so that the position of the interface 11 is in the state of (2) or (3) is supplied by the heater 40 provided in the heat receiving unit 2, and the heat radiating unit 4 is roughly insulated. The variable conductance heat pipe is operated to keep the temperature of the heat receiving unit 2 at an arbitrary set temperature with a small amount of heat. It should be noted that the heater 40 may be operated regardless of the operation of the cooled object 9 and linked to the non-operation of the cooled object 9 (for example, the power supply for the cooled object 9 and the power supply for the heater 40 are switched by a switch) or The heater 40 may be operated by detecting the non-operation (the heater is switched on by detecting that the operation of the object 9 to be cooled is turned off electrically or by a temperature sensor).

  FIG. 2 shows an example of the heat load dependency of the temperature of the heat receiving section 2 of the variable conductance heat pipe 20. The ◆ mark in the figure is a normal heat pipe (no non-condensable gas), and the temperature of the heat receiving part increases linearly with the increase of the heat load (the same applies to normal coolers). A variable conductance heat pipe according to the present invention is 50 ° C. which is approximately close to a set temperature (temperature during operation of the cooled object 9, for example, 53 ° C.) with a heat load of about 5 W. That is, when the operation of the cooled object 9 is stopped and waiting for the start of operation, that is, if the heater 40 generates 5 W of heat during standby, the cooled object 9 is set to 50 ° C. during standby. be able to. Even if the cooled object 9 is operated in this state and the amount of heat generated during operation becomes 50 W, for example, the cooled object 9 only rises to 53 ° C. and 3 ° C., so the time until the steady state is reached Is short. In most devices, the cooled object 9 can perform almost the same operation at 50 ° C. to 53 ° C., so that the cooled object 9 operates stably immediately after the start of the operation. As can be seen from FIG. 2, a heat load of about 65 W is required to set the temperature to 53 ° C. with a normal heat pipe, and according to the present invention, the temperature is set to a set temperature with 1/13 heat load of a normal heat pipe. The temperature will be very close. When cooling with a normal heat pipe, the difference between the set temperature and the ambient temperature is as high as 33K. Therefore, in the case of temperature control with a heater, a heat load of 65 W must always be input during standby. For this reason, a large waste of energy is generated, and a large-capacity heater, a wiring for a large current, and a power source must be provided in order to realize this, which is difficult to implement for a small device.

  As described above, according to the present invention, it is possible to perform reliable temperature control with a short time from energy saving to a steady state, that is, a desired function. In addition, since it is almost insulative during standby, the amount of heat applied during standby is not particularly related to the ability of the radiator, so it is highly efficient to keep the set temperature during operation of the cooled object 9 at a lower temperature. A heat radiator may be provided.

  In the present invention, the temperature of the heat receiving unit during standby is between the temperature Tr during operation of the cooled object 9 (53 ° C. in the example of FIG. 2) and the ambient temperature Te (20 ° C. in the example of FIG. 2). What is necessary is just to give the amount of heat | fever so that it may become this temperature to the heater 40. Preferably, the amount of heat at which the temperature of the heat receiving unit during standby is equal to or higher than the median value of Tr and Te, that is, (Tr + Te) / 2 (36.5 ° C. in the example of FIG. 2) may be given. As can be seen from FIG. 2, even if the temperature of the heat receiving unit during standby is merely given a heat quantity of (Tr + Te) / 2, if the cooled object 9 starts operating and generates a heat quantity of several watts or more, it is immediately 50 ° C. Thus, it can be seen that the effects of the present invention can be exhibited. In addition, the amount of heat exceeding that, that is, the temperature of the heat receiving unit during standby, is given as Te + 0.8 (Tr-Te) (80% of the temperature between the ambient temperature and the operating temperature is closer to the operating time) or more. In other words, it can be seen that the body 9 to be cooled reaches the steady temperature at the time of operation faster and is more preferable.

  Here, when the object to be cooled 9 is, for example, a semiconductor laser (Laser Diode, LD), by passing a current smaller than the oscillation threshold to the LD, instead of generating heat by the heater, the LD, that is, the object to be cooled 9 itself Can generate heat. In the LD, when the flowing current is smaller than the oscillation threshold, laser oscillation does not occur, and laser light is not output, that is, laser oscillation is in a non-operating state. Further, in this state, the LD itself generates heat according to the value of the electric current input to the LD as a loss. In this configuration, without providing the heater 40, the temperature of the LD can be maintained at a substantially constant temperature during non-operation (when the laser is not oscillating, during standby) and during operation (when the laser is oscillating). Therefore, the LD can be oscillated in a certain manner immediately after the start of the oscillating operation, that is, the operation without fluctuations in the oscillation wavelength and output, so that the effect of the present invention can be exhibited particularly.

  As an application of the LD, there is an apparatus that uses an LD that generates visible light such as red or blue as a light source of a video device. In the case of video equipment, the light from this light source is captured by human eyes with a sense of color and brightness. Since changes in color, that is, wavelength and brightness, that is, output, are captured as large changes by human senses, video equipment is particularly required to have stability of the light source. For this reason, in an apparatus using an LD as a light source of a video device, the effect of the present invention that suppresses a change in the operation of the LD when the device starts up is particularly great. Needless to say, a separate heater 40 may be provided even when the object to be cooled 9 is an LD.

  Here, the LD has been described as an example of a configuration that does not provide the temperature raising heater 40 and heats the cooled object 9 itself, but this configuration is not limited to the LD. If the cooled body 9 itself is configured to generate heat by inputting a sufficiently small electric power compared to the time of operation, the cooled body 9 is an element or device having an electrical input such as a semiconductor other than an LD or other electronic devices. Anything is acceptable.

  Needless to say, the configuration in which the temperature raising heater is not provided is also applicable to Embodiments 2 to 4 described later.

  The sealed container 1 is an airtight container for storing the liquid 6, the vapor 7, and the non-condensable gas 8, and is preferably a metal that has almost no chemical reaction between the liquid 6 and the vapor 7 and the inner wall of the sealed container 1. For example, when the liquid 6 is water, the material of the sealed container 1 is preferably copper, and when ammonia is used, a material that does not generate non-condensable gas due to a chemical reaction, such as aluminum or stainless steel, is preferable.

  The heat insulating portion 3 is a passage through which the liquid 6, the vapor 7, and the non-condensable gas 8 move. The heat insulating part 3 may be exposed to a fluid such as air, may contact the structure to radiate heat, or may be insulated by providing a heat insulating material.

  The heat radiating unit 4 has a role of condensing and liquefying the steam 7 and releasing the latent heat released at that time to the cold heat source 10. The inner surface may be provided with a protrusion for increasing the heat transfer area in order to promote condensation, and may be provided with a passage for sucking the condensed liquid in order to make the condensed liquid film thinner. May be provided with fins that increase the heat transfer area in order to promote heat dissipation to the cold heat source 10. In addition, as above-mentioned, the heat-insulating part 3 and the thermal radiation part 4 may have the gas-liquid interface 15 located in the inside, and the one part bears the role of the channel | path or container which accommodates the non-condensable gas 8. FIG.

  The non-condensable gas reservoir 5 has a role of accommodating the non-condensable gas 8. When not in operation, the liquid 6, the vapor 7 and the non-condensable gas 8 may be accommodated. It is provided at the end farthest from the heat receiving portion 2 with respect to the flow path of the variable conductance heat pipe, and preferably provided at the uppermost portion of the constituent part so that the inflowing liquid 6 flows down to the heat radiating portion 4. good.

  The liquid 6 is a liquid that boils and evaporates and condenses, and may be a single component fluid such as water or ammonia, or may be a multicomponent fluid such as an antifreeze. The vapor 7 is a gas obtained by vaporizing the liquid 6 or a part of the liquid 6. The non-condensable gas 8 is a gas that does not condense under the use environment, and is helium, argon, neon, nitrogen, or the like under a normal environment. Preferably, it is a gas that does not chemically react with the material of the closed container 1, the liquid 6, and the vapor 7, and is preferably an inert gas. In addition, non-condensable gas generated by a chemical reaction between the sealed container 1 and the liquid 6 in the initial stage of encapsulation may be used.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing Embodiment 2 of the present invention. The first embodiment has a feature that the temperature of the heat receiving unit 2 can be set to an arbitrary temperature with small energy, but the main portion 12 (portion requiring temperature control) in the body 9 to be cooled is the heat receiving unit. In the case of being away from 2 (when the thermal inclusion 13 is present), even in the case of the first embodiment, a temperature difference corresponding to the thermal resistance of the thermal inclusion 13 occurs during non-operation. Therefore, in the present embodiment, by providing the heater 40 in the vicinity of the main part 12 in the object 9 to be cooled, only the temperature difference generated by the heat input from the heater 40 and the thermal resistance of the thermal inclusion 13 can be compensated. The temperature difference between operation / non-operation can be further reduced.

  In this case, since the temperature difference generated by the heat input from the heater 40 and the thermal resistance of the thermal inclusion 13 can be generated even during operation, the temperature of the main part 12 of the body 9 to be cooled is set to the heater 40. The temperature can be precisely controlled by heat input to the.

  Further, by mounting the heater 40 in the body 9 to be cooled, wiring is eliminated from the cooler (variable conductance heat pipe 20), and the maintainability is improved. Furthermore, when the power source and the control circuit provided outside the cooled body 9 are provided inside the cooled body 9, the maintainability is further improved. The configuration in which the heater 40 is mounted in the cooled object 9 can be applied to the cooled object 9 having the structure shown in FIG. 1 in which the thermal inclusion 13 is not provided between the cooled object 9 and the heat receiving portion 2. Needless to say.

Embodiment 3 FIG.
FIG. 4 is a block diagram showing Embodiment 3 of the present invention. A fan 14 for passing a cooling fluid is provided in the heat radiating portion 4 of the variable conductance heat pipe 20, a temperature sensor 15 is provided in the cooled object 9, and the output of the fan 14 and the heater 40 is controlled by the temperature sensor 15 and the control circuit 16. This is a configuration that optimizes temperature control. The fan 14 may be a pump that allows the cooling fluid to flow to the heat radiating portion. That is, the fan 14 may be any cooling device that cools the heat radiating unit 4.

  With this configuration, the object to be cooled 9 can be adjusted by heating / cooling via the variable conductance heat pipe 20, the transition time to the set temperature and the waiting time of the user can be shortened, and the object to be cooled 9 The operating temperature can be adjusted with higher accuracy. Furthermore, by optimal control, the output of the cooling device such as the pump or fan 14 and the heater 40 can be minimized, and the energy saving temperature can be controlled.

  In addition, although the case where the heater 40 was provided was demonstrated above, as described in Embodiment 1, you may make it the to-be-cooled body 9 generate | occur | produce heat without providing the heater 40. In this case, The output control may be performed by interlocking the object to be cooled and the cooling device.

Embodiment 4 FIG.
FIG. 5 is a block diagram showing Embodiment 4 of the present invention. In this structure, both the heat receiving portion 2 of the variable conductance heat pipe 20 and the cooled object 9 including the heater 40 are covered with a heat insulating material 17. With this configuration, it is possible to increase the temperature regulation efficiency of the cooled object 9, reduce heat dissipation when the set temperature is maintained, and reduce power consumption required during standby. More specifically, FIG. 2 shows the characteristics when not covered with the heat insulating material. However, if both the heat receiving portion 2 and the cooled object 9 including the heater are covered with the heat insulating material, the rise of the VCHP characteristics in FIG. The part is shifted to the left. Therefore, the amount of heat required to make the temperature of the heat receiving unit during standby the same as that when not covered with the heat insulating material is smaller than that when not covered with the heat insulating material.

  In addition, although the structure which covered both the heat receiving part 2 and the to-be-cooled body 9 containing a heater with the heat insulating material 17 was shown here, the structure which covers only one of the heat receiving part 2 or the to-be-cooled body 9 with a heat insulating material is also shown. There is an effect of reducing the amount of power consumption required at the time of standby as compared with a configuration without a heat insulating material.

It is a block diagram which shows the variable conductance heat pipe which concerns on Embodiment 1 of this invention. It is a figure which shows the thermal load dependence of the temperature of a variable conductance heat pipe and a normal heat pipe. It is a block diagram which shows the variable conductance heat pipe which concerns on Embodiment 2 of this invention. It is a block diagram which shows the variable conductance heat pipe which concerns on Embodiment 3 of this invention. It is a block diagram which shows the variable conductance heat pipe which concerns on Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Heat receiving part, 3 Heat insulation part, 4 Heat radiation part, 5 Non-condensable gas reservoir part, 6 Liquid, 7 Vapor, 8 Non-condensable gas, 9 Cooled object, 10 Cooling heat source, 11 Interface, 12 Main part, 13 Heat inclusion, 14 Fan, 15 Temperature sensor, 16 Control circuit, 17 Heat insulation material, 20 Variable conductance heat pipe, 40 Heater.

Claims (9)

In a variable conductance heat pipe in which a working fluid and a non-condensable gas are sealed in a sealed container having a heat receiving part and a heat radiating part, a body to be cooled is installed in the heat receiving part, and the amount of heat is given to the heat receiving part during standby of the body to be cooled. A variable conductance heat pipe characterized by giving. 2. The variable according to claim 1, wherein the heat receiving unit or the object to be cooled is provided with an amount of heat such that the temperature of the heat receiving unit during standby is equal to or higher than the median of the temperature Tr during operation of the object to be cooled and the ambient temperature Te. Conductance heat pipe. The heat receiving part or the cooled object is provided with a heater for providing a heat quantity at which the temperature of the heat receiving part during standby is equal to or higher than the median of the temperature Tr during operation of the cooled object and the ambient temperature Te. 2. The variable conductance heat pipe according to 2. When the object to be cooled is on standby, the object to be cooled generates an amount of heat in which the temperature of the heat receiving unit at the time of standby is equal to or greater than the median of the temperature Tr and the ambient temperature Te during operation of the object to be cooled. Item 3. The variable conductance heat pipe according to Item 2. The variable conductance heat pipe according to claim 3, wherein a cooling device is provided in the heat radiating section, and the output is controlled in conjunction with the heater and the cooling device. The variable conductance heat pipe according to claim 4, wherein a cooling device is provided in the heat radiating unit, and the output is controlled in conjunction with the cooled object and the cooling device. The variable conductance heat pipe according to claim 1, wherein the object to be cooled is covered with a heat insulating material. The variable conductance heat pipe according to claim 3, wherein the heat receiving portion is covered with a heat insulating material. 2. The variable conductance heat pipe according to claim 1, wherein the object to be cooled is a semiconductor laser element.

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