JP2012160629A - Heat exchanger and electronic device - Google Patents

Abstract

An object of the present invention is to efficiently circulate a liquid in a closed circulation path.
A flow path in which a liquid is enclosed, wherein the flow path has elasticity, and a pump communicates with an inlet and an outlet of the flow path, and discharges the liquid at a predetermined discharge pressure. A pump for circulating in the flow path, and the flow path and the pump constitute a closed system circulation flow path, and the pressure in the flow path when the pump is not driven is one of the discharge pressures of the pump / 2 or more heat exchange device.
[Selection] Figure 3

Description

  The present invention relates to a heat exchange device and an electronic apparatus.

  A cooling mechanism for cooling a device that generates heat is used. Among such cooling mechanisms, there is one that circulates cooling water in the flow path by a pump. And the apparatus which heat | fever-generates with the circulated cooling water is cooled.

  Patent Document 1 discloses that in a projector device, a cooling liquid is constantly circulated and cooled by a circulation pump.

JP-A-8-242463

  When the pump is driven in the closed circulation path, a pressure difference due to the pump driving occurs between the discharge side and the supply side of the pump. If it does so, a deformation | transformation will arise in the flow path of a cooling water, and a bias will arise in the fluid volume in the flow path before and behind a pump. When the driving is continued as it is, there is a problem that the supply side pressure becomes a negative pressure, and the output characteristics of the pump deteriorate. Therefore, it is desirable to circulate the liquid efficiently without reducing the output characteristics of the pump in the closed circulation path.

  This invention is made | formed in view of such a situation, and it aims at circulating a liquid efficiently in a closed system circulation flow path.

The main invention for achieving the above object is:
A liquid is sealed inside and has a flow path having elasticity;
A pump that communicates with an inlet and an outlet of the flow path and circulates the liquid in the flow path by discharging the liquid at a predetermined discharge pressure;
With
It is a heat exchange device in which the pressure inside the flow path when the pump is not driven is equal to or greater than ½ of the predetermined discharge pressure.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

FIG. 1A is a schematic view of a closed system circulation channel in the present embodiment, and FIG. 1B is a schematic cross-sectional view of a pump 10. It is a figure explaining the difference between the pressure of a closed system flow path, and the pressure of an open type flow path. It is explanatory drawing of the pressure distribution in the flow path in this embodiment. It is a figure explaining the upper limit of the pressure in a flow path. It is a 1st figure explaining the determination method of the preload in the flow path in this embodiment. It is a 2nd figure explaining the determination method of the preload in the flow path in this embodiment.

At least the following matters will become clear from the description of the present specification and the accompanying drawings.
A liquid is sealed inside and has a flow path having elasticity;
A pump that communicates with an inlet and an outlet of the flow path and circulates the liquid in the flow path by discharging the liquid at a predetermined discharge pressure;
With
The heat exchange device, wherein a pressure inside the flow path when the pump is not driven is equal to or more than ½ of the predetermined discharge pressure.
By doing so, the pressure inside the flow path when the pump is not driven is equal to or more than ½ of the discharge pressure of the pump, and when the pump is not driven, pressure is preliminarily applied to the inside of the flow path. It is in the state. Therefore, when the pump is driven, it is possible to prevent the pressure inside the flow path on the side where the liquid is supplied to the pump from becoming a negative pressure. As a result, the liquid can be efficiently circulated without depleting the liquid.

In such a heat exchange device, it is preferable that the pressure in the flow path when the pump is not driven is ½ of the discharge pressure of the pump.
By doing in this way, while being able to circulate a liquid efficiently, the freedom degree of the layout of a flow path improves and a heat exchange apparatus can be reduced in size.

Moreover, it is desirable that a syringe is attached to the closed system circulation flow path, and the liquid is sealed by the syringe so that the pressure in the flow path becomes 1/2 or more of the discharge pressure of the pump.
By doing in this way, a preload can be applied to a closed system circulation channel with a syringe at the time of manufacture of a heat exchange device.

In addition, the liquid may be sealed in a pressurizing chamber so that the pressure in the flow path becomes 1/2 or more of the discharge pressure of the pump.
By doing in this way, a preload can be applied to a closed system circulation channel by a pressurization chamber at the time of manufacture of a heat exchange device.

The discharge pressure of the pump is preferably the discharge pressure when the supply port pressure of the pump is atmospheric pressure.
By doing in this way, the preload of a closed system circulation channel can be applied appropriately on the basis of atmospheric pressure.

The pump preferably includes a mechanism for preventing the liquid from flowing backward.
Thus, even when a pump having a mechanism for preventing backflow and having a pressure difference between the discharge side and the supply side is used, the liquid can be efficiently circulated in the closed system circulation channel.

Moreover, it is desirable that an electronic device includes the heat exchange device.
By providing the heat exchange device described above, the electronic apparatus is efficiently cooled, and thus a desired operation can be continuously performed.

In addition, at least the following matters will become clear from the description of the present specification and the accompanying drawings. That is,
A liquid is sealed inside and has a flow path having elasticity;
A pump that communicates with an inlet and an outlet of the flow path and circulates the liquid in the flow path by discharging the liquid at a predetermined discharge pressure;
The heat exchange in which the pressure in the flow path when the pump is not driven is a pressure obtained by adding 1/2 of the pressure obtained by subtracting the inflow pressure from the predetermined discharge pressure to the inflow pressure to the pump Device.
By doing so, the liquid can be supplied to the pump without lowering the pressure on the supply side below the atmospheric pressure of the use environment, so that the liquid can be efficiently circulated in the closed system circulation channel.

=== Embodiment ===
FIG. 1A is a schematic diagram of a heat exchange device 1 in the present embodiment. In the figure, the pump 10, the flow path 20, and the heat exchange object 30 are shown.

  One of the flow paths 20 is connected to the discharge side of the pump 10, and the other of the flow paths 20 is connected to the supply side of the pump 10. A liquid is sealed in a closed system circulation flow path (hereinafter also referred to as a closed flow path) constituted by the flow path 20 and the pump 10. The liquid to be sealed is, for example, water. The internal pressure of the liquid sealed in the closed system circulation channel is set to 1/2 or more of the discharge pressure of the pump. The reason for this will be described later.

  FIG. 1B is a schematic cross-sectional view of the pump 10. The pump 10 is for discharging the liquid flowing in from the supply side from the discharge side. As shown in FIG. 1B, the pump 10 includes a supply side flow path 102, a discharge side flow path 104, a buffer chamber 106, a valve 108, and a piezoelectric element 110. A liquid is supplied to the supply-side channel 102. The supplied liquid is temporarily stored in the buffer chamber 106. The piezoelectric element 110 expands and contracts in the direction of the buffer chamber 106 when a pulsed drive signal is supplied. As a result, the pressure under the valve 108 fluctuates, the valve 108 opens and closes, and the liquid flows into the discharge side flow path 104. Thus, by operating the pump 10, the liquid is sent from the supply side flow channel 102 to the discharge side flow channel 104.

  In the present embodiment, the pump 10 is preferably operated in a predetermined temperature range. This is because if the temperature falls outside the predetermined temperature range, an appropriate internal pressure cannot be obtained in the flow path 20 due to contraction or expansion of the liquid. For example, when the temperature is too low, the internal pressure in the flow path 20 becomes too low, and the liquid cannot be circulated efficiently for the reason described later. If the temperature is too high, the upper limit of the internal pressure described later may be exceeded due to liquid expansion. In this embodiment, the predetermined temperature range is 10 ° C. to 40 ° C.

  The flow path 20 is made of an elastically deformable material such as resin. A part of the flow path 20 is in contact with the heat exchange target 30 on the outside thereof, thereby exchanging heat between the heat exchange target 30 and the liquid in the flow path 20. The channel 20 may be an elastically deformable metal, and other materials can be used as long as they are elastically deformable. The channel 20 is more preferably made of a material having high thermal conductivity in order to increase the efficiency of heat exchange.

  The heat exchange target 30 generates heat, such as a CPU of a computer, and can be an electronic device, machine, or device that generates heat. Although not shown, a heat radiating plate may be provided in the flow path 20.

  FIG. 2 is a diagram illustrating the difference between the pressure in the closed system flow path and the pressure in the open system flow path. In the figure, the pressure distribution in the case of a closed system flow path is indicated by a dotted line, and the pressure distribution in the case of an open system flow path is indicated by a solid line. When the liquid is circulated by the pump 10, the pressure on the discharge side becomes higher than the pressure on the supply side in both the closed system flow path and the open system flow path. The figure shows a state in which the pressure is increased by Δp in the open channel.

  Here, the open-system flow path has, for example, a position where at least a part of the flow path connected to the pump supply side has a portion that is in contact with the atmosphere in the flow path, such as a position that is open to the atmosphere. is there.

  In the open system flow path, since a part of the flow path connected to the pump supply side is opened, the pressure at the supply port becomes substantially equal to the atmospheric pressure of the use environment. Therefore, the pump characteristics do not deteriorate, and the pressure at the pump discharge port is increased by Δp, and the pressure distribution in the flow path connected to the pump discharge port is Δp at the pump discharge port and one end opened to the atmosphere. 2 is linearly distributed as shown by the solid line in FIG.

  When the pump 10 as described above is used, the pulsating flow is generated in the vicinity of the discharge port, but the pulsation is attenuated by an action such as deformation of the flow path constituting the circulation flow path, and can be regarded as a steady flow. Therefore, in these figures, the pressure is linearly distributed.

  In the open system flow path, the pressure is distributed as shown by the solid line in FIG. 2 to deform the flow path and increase the flow path volume. The fluid is replenished.

  On the other hand, in a closed system flow path, assuming that there is no evaporation of liquid from the flow path, the amount of fluid in the flow path is constant, and therefore the flow volume on the pump discharge side increases due to pressure. Thus, the fluid on the pump supply side is deficient, and the pressure on the supply side becomes negative from the atmospheric pressure of the operating environment. Therefore, it is difficult to supply the liquid to the pump 10, and the characteristics of the pump deteriorate.

Therefore, in the closed system flow path in the present embodiment, in order to prevent the supply-side pressure from becoming a negative pressure under the above-described situation, a fluid exceeding the volume increment of the flow path in the case of the open system flow path is flowed in advance. It is sealed in the road and preload is applied in the flow path.
In this way, when the pump is driven in a closed system flow path, even if a fluid volume deviation occurs between the supply side and the discharge side of the pump, the pressure in the flow path is similar to the open system flow path. Since the distribution is higher than atmospheric pressure from the pump discharge port to the supply port, the pressure in the flow path does not become negative from the atmospheric pressure in the operating environment at any position in the flow path, and the pump characteristics do not deteriorate .

  FIG. 3 is an explanatory diagram of the pressure distribution in the flow channel in the present embodiment. In the figure, the pressure distribution in the case of a closed system flow path is indicated by a dotted line, and the pressure distribution in the case of an open system flow path is indicated by a solid line. In this embodiment, the pressure in the closed system flow path is raised by Δp / 2 as a whole. Here, the reference pressure is atmospheric pressure.

  In the drawing, the pressure distribution in the sealed flow path when no preload is applied to the closed flow path is shown by a one-dot chain line for reference. (This corresponds to the pressure distribution indicated by the dotted line in FIG. 2). When the preload is not applied, as described above, the pressure on the supply side of the pump becomes a negative pressure from the atmospheric pressure of the use environment, and the pump characteristics are deteriorated.

  As shown in FIG. 2 described above, Δp is a pressure generated by driving the pump 10 in the open system flow path. That is, Δp is the discharge pressure of the pump 10. Therefore, in the present embodiment shown in FIG. 3, the pressure in the closed system flow path (corresponding to the closed system circulation flow path) is pre-pressed to be 1/2 or more of the discharge pressure of the pump 10 as a whole. That is, the internal pressure of the closed flow path when the pump 10 is not driven is preloaded so as to be equal to or greater than Δp / 2.

  In other words, the pressure in the flow path 20 when the pump 10 is not driven is a pressure obtained by adding 1/2 of the pressure obtained by subtracting the supply side pressure from the discharge pressure of the pump 10 to the supply side pressure of the pump 10. It can be said that there is.

  Such a heat exchanging device 1 may be manufactured by applying pressure with a syringe to inject liquid into a closed system flow path, and sealing when the preload is increased by Δp / 2. Further, the heat exchange device 1 may be manufactured by enclosing a liquid in a closed flow path in a pressurized chamber whose pressure is increased by Δp / 2.

  Thus, when the pump 10 is not driven, the pressure in the flow path 20 is ½ or more of the discharge pressure of the pump 10, so that the liquid is supplied to the supply side without being deficient when the pump 10 is driven. can do. And a liquid can be circulated efficiently.

  FIG. 4 is a diagram for explaining the upper limit of the pressure in the flow path. In the figure, the upper limit of the pressure in the flow path is indicated by a two-dot chain line. The pressure in the flow path is the highest at the discharge port of the pump 10, but the pressure is set to a pressure that is lower than the strength of the pump 10, the flow path 20, and their connecting portions.

Further, when the preload amount is Δp1 (Δp1 ≧ Δp / 2), the pump discharge port pressure when the pump is driven is a pressure obtained by adding 1/2 of the pump discharge pressure Δp and the preload amount Δp1. That is, the highest pressure in the pressure distribution in the flow path is Δp1 + Δp / 2. Of the pump 10, the flow path 20, and their connected parts, if the pressure resistance of the lowest strength part is Δpd, it is necessary to satisfy Δp1 + Δp / 2 <Δpd.
That is, the preload amount Δp1 satisfies the following relationship.
Δp / 2 ≦ Δp1 <Δpd−Δp / 2

  Therefore, in the above formula, Δpd is at least higher than Δp, so that the fluid can be circulated in the closed circulation channel without deteriorating the pump characteristics. However, the withstand voltage Δpd is assumed in consideration of the safety factor. It is desirable that the pressure be about three times the maximum pressure (Δp1 + Δp / 2).

  Further, if the preload Δp1 is increased more than necessary, the pressure resistance Δpd required for the closed system circulation flow path increases, so that the tube that is the flow path is thickened, and the hardness of the material constituting the flow path is increased. As a result, since the flexibility of the flow path is reduced and the layout of the flow path is greatly limited, it is more desirable that the withstand voltage Δpd is as small as possible as long as the pump characteristics are not deteriorated. Therefore, the preload amount Δp1 is Δp / 2 or more, and more desirably Δp / 2.

  Next, the reason why the preload in the flow path is set to 1/2 or more of the pump discharge pressure as described above will be described.

  FIG. 5 is a first diagram illustrating a method for determining the preload in the flow channel in the present embodiment. The figure shows a slight displacement u in the radial direction at a position of an arbitrary radius r when the internal pressure p is received. Further, the outer diameter of the flow path is represented by b, and the inner diameter is represented by a. Further, a minute length in the longitudinal direction of the flow path is assumed to be Δl.

At this time, the radial displacement u at the position of the radius r is
It becomes. Here, ν is the Poisson's ratio of the substance constituting the flow path, and E is the Young's modulus of the substance constituting the flow path.

When r = a as the displacement of the inner wall,
Is established.

Where
age,
And

The increase in volume ΔV due to the change in inner diameter from a to a + u (a) is
It becomes. In the above equation, u (a) ² is neglected because it is a very small term compared to a.

When the total length of the flow path is L, the volume increment of the flow path can be obtained by integrating x from 0 to L. Here, the volume increment of the flow path when the pressure distribution in the case of the open flow path (solid line in FIG. 2) is obtained.
The volume V obtained by the equation (1) is the volume increment of the channel in the case of an open channel. If the volume V is enclosed in the closed system flow path in advance, even if the fluid volume is unbalanced between the supply side and the discharge side of the pump when the pump is driven in the closed system flow path, the open system Like the flow path, the pressure in the flow path is more than the atmospheric pressure from the pump discharge port to the supply port, so the pressure in the flow path is more negative than the atmospheric pressure in the operating environment at any position in the flow path. That is, the pump characteristics are not deteriorated.

FIG. 6 is a second diagram illustrating the method for determining the preload in the flow path in the present embodiment. Assuming a state in which the liquid of the above increment V is sealed in a closed system flow path and the internal pressure Δp ′ is uniformly applied in the flow path as shown in FIG.
It becomes. Comparing equation (1) and equation (2),
It becomes. That is, the pressure to be sealed is ½ of the driving pressure Δp of the pump 10. Therefore, it is sufficient to enclose the liquid so that the internal pressure of the closed system flow path becomes a pressure equal to or more than ½ of the driving pressure Δp of the pump 10.

  In the present embodiment, the heat exchange target 30 generates heat, and an example in which the closed circulation path is used for cooling has been described. However, not limited to cooling, the heat exchange target 30 is heated. Also good.

1 heat exchanger,
10 pumps,
20 channels,
30 Heat exchange target

Claims (8)

A liquid is sealed inside and has a flow path having elasticity;
A pump that communicates with an inlet and an outlet of the flow path and circulates the liquid in the flow path by discharging the liquid at a predetermined discharge pressure;
With
The heat exchange device, wherein a pressure inside the flow path when the pump is not driven is equal to or more than ½ of the predetermined discharge pressure.   The heat exchange device according to claim 1, wherein the pressure in the flow path when the pump is not driven is ½ of the discharge pressure of the pump. A syringe is attached to the circulation channel,
The heat exchange device according to claim 1, wherein the liquid is sealed by the syringe so that the pressure in the flow path becomes 1/2 or more of the discharge pressure of the pump.   The heat exchange device according to claim 1 or 3, wherein the liquid is sealed in a pressurizing chamber so that the pressure in the flow path becomes 1/2 or more of the discharge pressure of the pump.   The heat exchange device according to any one of claims 1 to 4, wherein the discharge pressure of the pump is a discharge pressure when a supply port pressure of the pump is an atmospheric pressure.   The heat exchange apparatus according to any one of claims 1 to 5, wherein the pump includes a mechanism for preventing a back flow of the liquid.   An electronic device comprising the heat exchange device according to claim 1. A liquid is sealed inside and has a flow path having elasticity;
A pump that communicates with an inlet and an outlet of the flow path and circulates the liquid in the flow path by discharging the liquid at a predetermined discharge pressure;
With
The heat exchange in which the pressure in the flow path when the pump is not driven is a pressure obtained by adding 1/2 of the pressure obtained by subtracting the inflow pressure from the predetermined discharge pressure to the inflow pressure to the pump apparatus.