Foreign substance removal apparatus, circulation system and vehicle cooling system

This invention is a foreign substance removal apparatus that removes foreign substances in such a medium as a refrigerant that flows through a circulation path, the foreign substance removal apparatus including: a foreign substance sedimentation unit which is connected to the circulation path and is configured to settle the foreign substances; a foreign substance separation unit configured to separate, from the foreign substance sedimentation unit, the foreign substances settled in the foreign substance sedimentation unit; first pressure open/close means which is disposed on a bottom of the foreign substance sedimentation unit, and is configured to open or close in accordance with pressure inside the circulation path; and a foreign substance discharge pipe which connects the bottom of the foreign substance sedimentation unit and the foreign substance separation unit via the first pressure open/close means.

TECHNICAL FIELD

The present invention relates to a foreign substance removal apparatus for removing foreign substances in a medium (e.g. refrigerant) which flows through a circulation path (e.g. sealed medium circulation path), and a circulation system and a vehicle cooling system equipped with this foreign substance removal apparatus.

BACKGROUND ART

A circulation system, which uses such liquid as water as a refrigerant, is generally known as a circulation system that is used for cooling such a cooling target object as a CPU (Central Processing Unit), an LSI (Large Scale Integration), an inverter and a power semiconductor. In this circulation system, a circulation path is formed using a metal material having high thermal conductivity (e.g. aluminum, copper), and the cooling target object is cooled by circulating the refrigerant through the circulation path using a circulation pump to cause a heat exchange between the cooling target object and the refrigerant.

In the case of using the above circulation system for a vehicle cooling system, a mixed solution (antifreeze solution), which contains ion-exchanged water having little content impurity, an organic solvent having a low freezing point (e.g. ethylene glycol), and an anti-corrosive agent to suppress corrosion of metal material, is used. The refrigerant is normally exchanged by an apparatus manufacturer, automobile manufacturer, maintenance provider or the like, but may be exchanged by the user in some cases, and for this, tap water may be used instead of ion-exchanged water. Tap water contains corrosive factors that corrode metal material, such as chloride ions, metal ions and dissolved oxygen, hence metal material constituting the circulation path may corrode and enter into the tap water, or the corrosive factors that corrode metal material may precipitate inside the circulation path. Further, tap water also contains scale forming factors, such as calcium ions, magnesium ions, ionic silica and dissolved carbon dioxide, hence scales (e.g. calcium carbonate scales, magnesium carbonate scales, silica scales) may form inside the circulation path. As a result, the circulation path is clogged by these corrosion products or scales, which drops the cooling efficiency of the cooling target object, and increases pump load when the circulation system is operated.

In recent years, as the improvement of cooling target objects (e.g. electronic devices, power semiconductors) accelerate, the heating values of such cooling target objects are increasing. Therefore, the circulation path of the circulation system is miniaturized so as to improve the cooling efficiency of the cooling target object. However, if the circulation path is miniaturized, the clogging of the circulation path occurs more easily, even by micro foreign substances (e.g. corrosion products, scales) that mix in, and the clogging of the circulation path leads to a drop in the cooling efficiency of the cooling target object, and an increase in the pump load when the circulation system is operated.

As described above, the foreign substances that enter the medium, such as refrigerant, clog the circulation path and cause various problems, therefore foreign substances in the medium must be efficiently removed.

PTL 1 proposes a method for removing foreign substances in the medium by disposing a detachable filter in the circulation path. Further, PTL 2 proposes a foreign substance removal apparatus in which a foreign substance sedimentation unit is disposed at a position that branches from the circulation path.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The method according to PTL 1 can remove the foreign substances in the medium using a filter, but the filter gradually becomes clogged over time, hence the filter, to which the foreign substances adhere, must be frequently detached and cleaned.

In the case of the foreign substance removal apparatus according to PTL 2, the circulation path and the foreign substance sedimentation unit are divided by a partition wall, but are still connected, therefore the foreign substances may be stirred up and enter the circulation path from the foreign substance sedimentation unit. Furthermore, the circulation path and the foreign substance segmentation unit of this foreign substance removal apparatus are integrated, which makes it difficult to discharge the foreign substances that are settled in the foreign substance sedimentation unit to the outside.

With the foregoing in view, it is an object of the present invention to provide a foreign substance removal apparatus that can remove foreign substances in the medium which circulates through the circulation path, can suppresses the removed foreign substances from being stirred up and flowing into the circulation path again, and can easily discharge the removed foreign substances to the outside, and a circulation system and a vehicle cooling system equipped with this foreign substance remove apparatus.

Solution to Problem

The present invention is a foreign substance removal apparatus that removes foreign substances in a medium that flows through a circulation path, the foreign substance removal apparatus including: a foreign substance sedimentation unit which is connected to the circulation path and is configured to settle the foreign substances; a foreign substance separation unit configured to separate, from the foreign substance sedimentation unit, the foreign substances settled in the foreign substance sedimentation unit; first pressure open/close means which is disposed on a bottom of the foreign substance sedimentation unit, and is configured to open or close in accordance with pressure inside the circulation path; and a foreign substance discharge pipe which connects the bottom of the foreign substance sedimentation unit and the foreign substance separation unit via the first pressure open/close means.

The present invention is also a circulation system in which a cooling device configured to cool a cooling target object using a refrigerant, and a heat radiator configured to cool the refrigerant are connected via a circulation pipe, wherein the foreign substance removal apparatus is disposed in the middle of the circulation pipe.

Further, the present invention is a vehicle cooling system that cools an in-vehicle electronic device, the vehicle cooling system having the circulation system, wherein the cooling target object of the circulation system includes the in-vehicle electronic device.

Advantageous Effects of Invention

According to the present invention, a foreign substance removal apparatus, that can remove foreign substances in the medium which circulates through the circulation path, can prevent the removed foreign substances from being stirred up and flowing into the circulation path again, and can easily discharge the removed foreign substances to the outside, and a circulation system and a vehicle cooling system equipped with this foreign substance removal apparatus can be provided.

DESCRIPTION OF EMBODIMENTS

Embodiments of a foreign substance removal apparatus and a circulation system according to the present invention will be described with reference to the drawings. The present invention, however, is not limited to the embodiments which are described below. The dimensions and shapes of each composing element in the drawings are simplified to make description easier, and may be different from actual dimensions and shapes.

FIG. 1is a schematic diagram depicting a circulation system which includes the foreign substance removal apparatus according to the present embodiment.

InFIG. 1, the circulation system1includes: a cooling device3which cools a cooling target object2; a radiator (heat radiator)4which cools a refrigerant circulating in the circulation system1; a circulation pipe5which connects the cooling device3and the radiator4; a circulation pump6which circulates the refrigerant between the cooling device3and the radiator4; and a foreign substance removal apparatus7which is disposed in the middle of the circulation pipe5. The positions of the circulation pump6and the foreign substance removal apparatus7are not limited to the positions inFIG. 1, as long as connections are in the middle of the circulation pipe5, but it is preferable that the foreign substance removal apparatus7is connected to a position in the middle of the circulation pipe5where the refrigerant flows from the cooling device3to the radiator4. This is because the refrigerant, the temperature of which rises by the heat exchange in the cooling device3, is introduced to the foreign substance removal apparatus7, and as a result, first pressure open/close means11(described later) of the foreign substance removal apparatus7opens more easily when the pressure inside the circulation path increases (that is, the response speed of the first pressure open/close means11with respect to the increase in pressure in the circulation path becomes faster), whereby the foreign substance removal effect improves.

In the circulation system1having this configuration, the refrigerant cooled by the radiator4is introduced to the cooling device3by the drive force of the circulation pump6via the circulation pipe5. The refrigerant introduced to the cooling device3cools the cooling target object2by a heat exchange with the cooling target object2. The refrigerant, which is heated by the heat exchanged with the cooling target object2, is introduced to the radiator4by the drive force of the circulation pump6via the circulation pipe5, and is cooled by the radiator4. By circulating the refrigerant between the cooling device3and the radiator4like this, the cooling target object2can be continuously cooled.

The circulation system1here is not especially limited as long as the system can circulate the refrigerant as described above. The circulation system1can be used for a vehicle cooling system, for example. In the case of using the circulation system1for the vehicle cooling system, the flow rate of the refrigerant that circulates through the circulation system1can be determined in accordance with the cooling performance of the cooling device3, and is normally about 5 L/min. or more, 15 L/min. or less.

In this description, an example of using the refrigerant as the medium is primarily described, but needless to say, the present invention can also be applied to a hot water heating system, an air conditions system and the like by using a heat medium, instead of a refrigerant, for the medium.

The cooling target object2is not especially limited, and any known heating element in this technical field can be used. Examples of the cooling target object2are such electronic components as a CPU, an LSI circuit, an inverter and a power semiconductor.

The cooling device3is not especially limited, and any known cooling device in this technical field can be used. The cooling device3generally includes a heat sink which plays a role of performing heat exchange between the cooling target object2and the refrigerant. In terms of improving the heat exchange efficiency by increasing the contact area with the refrigerant, a channel fin or the like may be disposed. The heat sink is formed of a metal material having high thermal conductivity, such as aluminum, copper and stainless steel.

The radiator4and the circulation pipe5are not especially limited, and any known radiator and circulation pipe in this technical field can be used.

The temperature of the refrigerant before operating the circulation system1is normally an ambient temperature. The temperature of the refrigerant when the circulation system1is operating differs depending on the type of the cooling target object2or the like. For example, in the case of the vehicle cooling system, the temperature of the refrigerant is about 65° C. in normal operation, and the temperature difference of the refrigerant between the inlet and outlet of the cooling device3is 15° C. In concrete terms, the temperature of the refrigerant is about 50° C. at the entrance of the cooling device3, and the temperature of the refrigerant at the outlet of the cooling device3is about 80° C. In the flow channel of the refrigerant inside the cooling device3, about a 50° C. to 80° C. temperature gradient is generated from the upstream (inlet) side to the downstream (outlet) side.

The refrigerant that circulates between the cooling device3and the radiator4may include corrosive factors and scale forming factors of the member used for the circulation path, and foreign substances, due to these factors, may mix in. Therefore in this circulation system1, the foreign substances mixed in the refrigerant are removed by the foreign substance removal apparatus7.

In this description, “foreign substances” refers to solid foreign substances (e.g. corrosion products, scales) that mix in such a medium as a refrigerant. In this description, “refrigerant” refers to such a liquid as water (ion-exchanged water, tap water), an organic solvent with a low freezing point (e.g. ethylene glycol), an antifreeze solution, and a mixed solution thereof. And in this description, “circulation path” refers to a flow channel where such a medium as a refrigerant circulates, and specifically refers to flow channels in the cooling device3and the radiator4where the refrigerant flows the circulation pipe5. In this description, “corrosive factor” of a member used for the circulation path refers to a component that corrodes metal material, such as chloride ions, dissolved oxygen, iron ions and copper ions. And in this description, “scale forming factor” refers to calcium ions, magnesium ions, ionic silica, dissolved carbon dioxide or the like.

The foreign substance removal apparatus7is disposed in the middle of the circulation path, preferably in the middle of the circulation pipe5, and even more preferably in the middle of the circulation pipe5where the refrigerant flows from the cooling device3to the radiator4.FIG. 2Ashows enlarged cross-sectional views of the foreign substance removal apparatus7according to the present embodiment.

InFIG. 2A, the foreign substance removal apparatus7includes: a foreign substance sedimentation unit8which is disposed in the middle of the circulation pipe5; a foreign substance separation unit9; a foreign substance discharge pipe10which connects the bottom of the foreign substance sedimentation unit8and the foreign substance separation unit9; and first pressure open/close means11which is disposed in the foreign substance discharge pipe10.

The foreign substance sedimentation unit8is disposed to settle the foreign substances13in the refrigerant12to the bottom of the foreign substance sedimentation unit8by self weight. The foreign substance sedimentation unit8is formed as a part of the circulation path where the refrigerant12circulates. The circulation path is filled with the refrigerant12, and is sealed.

It is preferable that the vertical sectional area of the foreign substance sedimentation unit8is larger than the vertical sectional area of a tubular inlet or a tubular outlet of the circulation pipe5. By this shape, the flow speed of the refrigerant12, which flows through the foreign substance sedimentation unit8, decreases, which makes it easier for the foreign substances13to settle in the foreign substance sedimentation unit8. In other words, the foreign substances13efficiently settle downward in the vertical direction in the foreign substance sedimentation unit8due to a specific gravity difference between the refrigerant12and the foreign substances13, and the refrigerant12after the foreign substances13are removed can be supplied to the circulation pipe5.

In this description, “vertical sectional area” refers to the sectional area in the vertical direction with respect to the flowing direction of the refrigerant12. this description, “tubular inlet of the circulation pipe5” refers to an opening of the circulation pipe5through which the refrigerant12is guided to the foreign substance sedimentation unit8, and “tubular outlet of the circulation pipe5” refers to an opening of the circulation pipe5through which the refrigerant12is guided out of the foreign substance sedimentation unit8.

It is preferable that the horizontal sectional area of the foreign substance sedimentation unit8decreases toward the bottom (in the vertical direction). In concrete terms, it is preferable that the wall surface of the foreign substance sedimentation unit8is inclined toward the bottom surface. By this shape, the foreign substances13are easily collected at the bottom of the foreign substance sedimentation unit8to which the foreign substance discharge pipe10is connected, hence the foreign substances13can be efficiently discharged to the foreign substance separation unit9.

It is preferable that the circulation pipe5, which is connected to the foreign substance sedimentation unit8, is disposed in the upper part of the wall surface of the foreign substance sedimentation unit8. Further, the tubular inlet of the circulation pipe5, which guides the refrigerant12to the foreign substance sedimentation unit8, is open in the horizontal direction inFIG. 2A, but may be open downward in the vertical direction as depicted inFIG. 3. If the tubular inlet of the circulation pipe5is open downward in the vertical direction, the foreign substances13in the refrigerant12can be supplied to an area near the bottom of the foreign substance sedimentation unit8, therefore the foreign substances13can be more easily settled on the bottom of the foreign substance sedimentation unit8. Further, the moving distance of the refrigerant12in the foreign substance sedimentation unit8increases because the distance between the foreign substance sedimentation unit8to the tubular outlet of the circulation pipe5, which guides the refrigerant12out of the foreign substance sedimentation unit8, increases. As a result, the settling time of the foreign substances13in the foreign substance sedimentation unit8can be longer, and even foreign substances13, the specific gravity of which is light, can be more easily settled.

The foreign substance separation unit9is disposed to separate the foreign substances13that are settled in the foreign substance sedimentation unit8from the foreign substance sedimentation unit8. The foreign substance separation unit9also contains the refrigerant12and the foreign substances13discharged from the bottom of the foreign substance sedimentation unit8, and supplies the refrigerant12when the pressure inside the circulation path decreases. In other words, in addition to the role of a storage unit to store the foreign substances13discharged from the bottom of the foreign substance sedimentation unit8, the foreign substance separation unit9plays a role of a storage unit to store the refrigerant12, which is discharged from the circulation path when the pressure in the circulation path increases, and is supplied to the circulation path when the pressure in the circulation path decreases. Since this foreign substance separation unit9can be used as a reserve tank in a conventional circulation system1, the circulation system1can be downsized.

The foreign substance separation unit9is disposed as a member separate from the foreign substance sedimentation unit8, and is open to the air, and is configured so as to be easily detached from the foreign substance sedimentation unit8. In the foreign substance separation unit9, a part of the refrigerant12is stored, so that when the pressure inside the circulation path decreases, the refrigerant12is supplied from the foreign substance separation unit9to the circulation path. Further, in the upper part of the foreign substance separation unit9, there is a space to store the refrigerant12that is discharged from the circulation path when the pressure inside the circulation path increases.

The foreign substance separation unit9is connected with the bottom of the foreign substance sedimentation unit8via the foreign substance discharge pipe10. The foreign substance separation unit9is disconnected from the foreign substance sedimentation unit8by the first pressure open/close means11disposed in the foreign substance discharge pipe10. When the first pressure open/close means11is closed (that is, when the foreign substance sedimentation unit8and the foreign substance separation unit9are disconnected), the refrigerant12hardly flows in the foreign substance separation unit9. Therefore the foreign substances13more easily settle on the bottom of the foreign substance separation unit9by self weight, and the foreign substances13discharged from the foreign substance sedimentation unit8to the foreign substance separation unit9hardly return to the foreign substance sedimentation unit8. The foreign substance separation unit9is connected with the foreign substance sedimentation unit8by opening the first pressure open/close means11in accordance with the increase/decrease of the pressure in the circulation path.

As illustrated inFIG. 4A, a division plate20may be disposed inside the foreign substance separation unit9. For example, in the case of using the circulation system1for a vehicle cooling system, foreign substances13settled on the bottom of the foreign substance separation unit9may be stirred up by the vibration of the vehicle, and the foreign substances13may flow into the foreign substance sedimentation unit8when the first pressure open/close means11is opened. However, even if the foreign substances13settled on the bottom of the foreign substance separation unit9are stirred up by the vibration of the vehicle, the foreign substances13collide with the division plate20if there is a division plate20inside the foreign substance separation unit9, hence stirring up of the foreign substances13beyond the division plate20can be suppressed, and the foreign substances13are less likely to flow into the foreign substance sedimentation unit8when the first pressure open/close means11is opened.

It is preferable that the division plate20, disposed inside the foreign substance separation unit9, is located at the upper region of the bottom of the foreign substance separation unit9, such that most of the bottom of the foreign substance separation unit9is covered, whereby even if the foreign substances13settled on the bottom of the foreign substance separation unit9are stirred up, the foreign substances13can more easily collide with the division plate20. In this description, “most of the bottom of the foreign substance separation unit9” refers to 80% or more, preferable 85% or more, ideally 90% or more, of the bottom area of the foreign substance separation unit9.

The method of disposing the division plate20in an upper region of the bottom of the foreign substance separation unit9is not especially limited, but, for example, a part of the division plate20is fixed to the side wall of the foreign substance separation unit9, as illustrated inFIG. 4A. A division plate20having legs may be disposed inside the foreign substance separation unit9.

The number of division plates20, and a shape, size orientation and the like of each division plate are not especially limited, as long as the above effect is acquired.

For example, the number of division plates20may be one as illustrated inFIG. 4B, or may be two as illustrated inFIG. 4AandFIG. 4C. The number of the division plates20may be three or more, although this is not illustrated.

The orientation of the division plate20may be horizontal (parallel), or inclined, with respect to the bottom of the foreign substance separation unit9. If a part of the division plate20is fixed to the side wall of the foreign substance separation unit9, it is preferable that the division plate20is disposed so as to be inclined downward in the vertical direction from the side wall of the foreign substance separation unit9as illustrated inFIG. 4AtoFIG. 4C. If the division plate20is disposed like this, not only can stirring up of the foreign substances13be suppressed, but also the deposition of the foreign substances13on the division plate20can be prevented, hence the foreign substances13can be stably separated from the bottom of the foreign substance separation unit9.

In the case of using the circulation system1for a vehicle cooling system, a vibration proof material, such as vibration proof rubber, may be disposed around the foreign substance separation unit9, in order to suppress the vibration of the foreign substance separation unit9caused by the vibration of the vehicle. It is preferable that the vibration material is disposed between the foreign substance separation unit9and a jig to support the foreign substance separation unit9. If the vibration proof material is disposed like this, vibration of the foreign substance separation unit9can be suppressed even if the vehicle vibrates, hence stirring up of the foreign substances13settled on the bottom of the foreign substance separation unit9can be suppressed, and the foreign substances13are less likely to flow into the foreign substance sedimentation unit8when the first pressure open/close means11is opened.

The foreign substance discharge pipe10is disposed to connect the bottom of the foreign substance sedimentation unit8and the foreign substance separation unit9via the first pressure open/close means11. The outlet (tip) of the foreign substance discharge pipe10connected to the foreign substance separation unit9is disposed in a position which is in the refrigerant12stored in the foreign substance separation unit9, and is distant from the bottom of the foreign substance separation unit9. If the outlet of the foreign substance discharge pipe10is disposed in such a position, stirring up of the foreign substances13settled on the bottom of the foreign substance separation unit9can be suppressed.

The orientation of the outlet of the foreign substance discharge pipe10connected to the foreign substance separation unit9is not especially limited, and may be downward in the vertical direction, in the horizontal direction, upward in the vertical direction or the like. However, it is preferable that the outlet of the foreign substance discharge pipe10connected to the foreign substance separation unit9is open upward in the vertical direction, as illustrated inFIG. 3. If the outlet of the foreign substance discharge pipe10is opened in this orientation, stirring up of the foreign substance13can be suppressed during supplying refrigerant12from the foreign substance separation unit9to the foreign substance sedimentation unit8when the pressure inside the circulation path has decreased, and the effect of preventing the mixing of the foreign substances13in the refrigerant12can be especially enhanced.

The foreign substance discharge pipe10may be extended as illustrated inFIG. 5, so that the distance between the foreign substance sedimentation unit8and the foreign substance separation unit9is longer. Here the vertical positional relationship between the foreign substance sedimentation unit8and the foreign substance separation unit9is not especially limited, and the foreign substance sedimentation unit8and the foreign substance separation unit9may be located at a same height, or the foreign substance separation unit9may be located above the foreign substance sedimentation unit8.

If the foreign substance discharge pipe10is extended, the foreign substance separation unit9need not be disposed below the foreign substance sedimentation unit8, hence the installation space is less restricted, and customization improves. Further, maintenance also improves, since the foreign substance separation unit9can be disposed in a position where removal is easy. For example, in the case of using the circulation system1for a vehicle cooling system, the foreign substance separation unit9can be disposed in a position where detachment is easy, such as a position inside a hood (e.g. engine compartment unit) which is opened for periodic inspection, hence the foreign substance separation unit9can be detached during periodic inspection, and the foreign substances13collected inside the foreign substance separation unit9can be cleaned.

The first pressure open/close means11is disposed on the bottom of the foreign substance sedimentation unit8, and opens or closes in accordance with the pressure inside the circulation path (particularly the foreign substance sedimentation unit8). By bringing the first pressure open/close means11into the open state, the foreign substance sedimentation unit8and the foreign substance separation unit9can be connected via the foreign substance discharge pipe10. The pressure inside the circulation path, when the first pressure open/close means11opens, is not especially limited, and can be appropriately adjusted depending on the intended use of the circulation system1. In concrete terms, the first pressure open/close means11may be configured to open when the pressure inside the circulation path becomes a predetermined value or more, or a predetermined value or less. For example, in the case when the circulation system1is used for a vehicle cooling system, and a mixed solution containing water and ethylene glycol is used as the refrigerant12, the first pressure open/close means11opens if the gauge pressure inside the circulation path becomes 0.6 kg/cm2to 1.6 kg/cm2(preferably 0.9 kg/cm2to 1.3 kg/cm2) or 0 kg/cm2or less. If the first pressure open/close means11is set to open at such pressure, the foreign substance removal effect can be implemented while maintaining the cooling performance of the cooling device3. A commercial radiator cap, for example, can be used as the first pressure open/close means11which has the above mentioned function.

FIG. 6shows cross-sectional views depicting the structure and the function of the first pressure open/close means11(radiator cap). The first pressure open/close means11has a first open/close valve (main pressure valve)22which includes a first pressure response unit21, and a second open/close valve (negative pressure valve)24which includes a second pressure response unit23. The first pressure response unit21and the second pressure response unit23are formed of materials that expand and contract in accordance with the pressure (e.g. a spring). The first open/close valve22opens or closes in accordance with the expansion/contraction of the first pressure response unit21to connect or disconnect the foreign substance sedimentation unit8and the foreign substance separation unit9. The second open/close valve24opens or closes in accordance with the expansion/contraction of the second pressure response unit23to connect or disconnect the foreign substance sedimentation unit8and the foreign substance separation unit9.

FIG. 6Ais a cross-sectional view of the first pressure open/close means11in the case when the pressure inside the circulation path increases. If the pressure inside the circulation path increases, the first pressure response unit21contracts, and the first open/close valve22is pushed up and enters the open state, and the second pressure response unit23expands and the second open/close valve24is pushed up and enters the close state. Therefore if the pressure inside the circulation path increases, the foreign substance sedimentation unit8and the foreign substance separation unit9are connected via the first open/close valve22which is in the open state, and the refrigerant12flows from the foreign substance sedimentation unit8to the foreign substance separation unit9, so as to relax the pressure inside the circulation path. At this time, the foreign substances13settled on the bottom of the foreign substance sedimentation unit8is powerfully discharged, along with the refrigerant12, to the foreign substance separation unit9.

When the pressure inside the circulation path is relaxed and stabilized thereafter, the first pressure response unit21expands and the first open/close valve22is pushed down and enters the close state, and the second pressure response unit23remains expanded and the second open/close valve24enters the close state. Since both the first open/close valve22and the second open/close valve24enter the close state, the foreign substance sedimentation unit8and the foreign substance separation unit9are disconnected. Therefore a no flow of the refrigerant12is generated between the foreign substance sedimentation unit8and the foreign substance separation unit9.

FIG. 6Bis a cross-sectional view of the first pressure open/close means11in the case when the pressure inside the circulation path decreased. If the pressure inside the circulation path decreases, the first pressure response unit21expands and the first open/close valve22is pushed down and enters the close state, and the second pressure response unit23contracts and the second open/close valve24is pushed down and enters the open state. Therefore if the pressure inside the circulation path decreases, the foreign substance sedimentation unit8and the foreign substance separation unit9are connected via the second open/close valve24which is in the open state, and the refrigerant12flows from the foreign substance separation unit9to the foreign substance sedimentation unit8, so as to relax the pressure inside the circulation path. At this time, a part of the refrigerant12stored in the foreign substance separation unit9is supplied (replenished) to the foreign substance sedimentation unit8.

In the foreign substance removal apparatus7having the above configuration, if foreign substances13mix into the refrigerant12in the circulation path, the foreign substances13settle on the bottom of the foreign substance sedimentation unit8(FIG. 2A). The refrigerant12, from which foreign substances13are separated in the foreign substance sedimentation unit8, are supplied to the circulation pipe5, and circulate through the circulation path.

If the operation of the circulation system1is continuous, the temperature of the refrigerant12rises from the ambient temperature to about 80° C. At this time, the volume of the refrigerant12expands as the temperature increases. However, the circulation path is sealed, hence the pressure inside the circulation path increases. When the first pressure open/close means11enters the open state in accordance with the increase of the pressure inside the circulation path, a strong flow of the refrigerant12is generated from the foreign substance sedimentation unit8to the foreign substance separation unit9to decrease (relax) the pressure inside the circulation path. In other words, the refrigerant12in the foreign substance sedimentation unit8is discharged to the foreign substance separation unit9via the foreign substance discharge pipe10, and the pressure inside the circulation path decreases. At this time, the foreign substances13settled on the bottom of the foreign substance sedimentation unit8are powerfully discharged along with the refrigerant12to the foreign substance separation unit9(FIG. 2B). Therefore the efficiency to remove the foreign substances13in the foreign substance sedimentation unit8is very high.

When the pressure inside the circulation path stabilizes at a predetermined value or less, the first pressure open/close means11enters the close state, and the foreign substance sedimentation unit8and the foreign substance separation unit9are disconnected. After this disconnection, the refrigerant12hardly flows in the foreign substance separation unit9, hence the foreign substances13settle on the bottom of the foreign substance separation unit9by self weight (FIG. 2C).

On the other hand, if the temperature of the refrigerant12decreases, as in the case of stopping the operation of the circulation system1, for example, the volume of the refrigerant12shrinks. However, the circulation path is sealed, hence the pressure inside the circulation path decreases. When the first pressure open/close means11opens in accordance with the decrease of the pressure inside the circulation path, the refrigerant12inside the foreign substance separation unit9is supplied to the foreign substance sedimentation unit8via the foreign substance discharge pipe10, and the pressure inside the circulation path increases (FIG. 2D). Since the outlet of the foreign substance discharge pipe10is disposed in a position distant from the bottom of the foreign substance separation unit9, and the foreign substances13in the foreign substance separation unit9are settled on the bottom, the foreign substances13hardly return to the foreign substance sedimentation unit8along with the refrigerant12.

When the pressure inside the circulation path stabilizes at a predetermined value or more, the first pressure open/close means11enters the close state, and the foreign substance sedimentation unit8and the foreign substance separation unit9are disconnected.

The foreign substance separation unit9can be easily detached from the foreign substance sedimentation unit8, so that the foreign substance separation unit9can be detected during a periodic inspection or the like, and can be reattached after the foreign substances13that collected inside are cleaned by washing. In concrete terms, the foreign substance separation unit9is detached in a state depicted inFIG. 2C, and the foreign substances13that collected inside are removed by washing. By periodic removal of the foreign substances13that collected inside the foreign substance separation unit9, the return of foreign substances13to the foreign substance sedimentation unit8along with the refrigerant12can be prevented with certainty.

As described above, the use of the foreign substance removal apparatus7of the present embodiment allows the removal of the foreign substances13in the refrigerant12when the pressure inside the circulation path increases, and controls the pressure inside the circulation path.

According to the foreign substance removal apparatus7of the present embodiment, the foreign substances13in the refrigerant12circulating in the circulation path can be removed, and reentry of the removed foreign substances13into the circulation path by being stirred up can be suppressed, and the removed foreign substances13can be easily discharged. Therefore the circulation system1and the vehicle cooling system equipped with this foreign substance removal apparatus7hardly causes clogging of the circulation path, and can prevent a drop in the cooling efficiency of the cooling target object2, and an increase in the pump load during operation can be prevented.

FIG. 7is an enlarged cross-sectional view depicting a foreign substance removal apparatus according to the present embodiment. The basic configuration of the foreign substance removal apparatus according to the present embodiment is the same as the foreign substance removal apparatus7according to Embodiment 1, hence only differences will be described.

InFIG. 7, the foreign substance removal apparatus7according to the present embodiment further includes a medium supply pipe14which connects the upper part of the foreign substance sedimentation unit8and the foreign substance separation unit9, and second pressure open/close means15which is disposed in the medium supply pipe14, in addition to the configuration of the foreign substance removal apparatus7according to Embodiment 1.

The medium supply pipe14is disposed to connect the upper part of the foreign substance sedimentation unit8and the foreign substance separation unit9via the second pressure open/close means15. An inlet (tip) of the medium supply pipe14connected to the foreign substance separation unit9is in the refrigerant12stored in the foreign substance separation unit9, and is in a position distant from the bottom of the foreign substance separation unit9. If the inlet of the medium supply pipe14is disposed in such a position, the inflow of the foreign substances13settling on the bottom of the foreign substance separation unit9can be prevented.

The orientation of the inlet of the medium supply pipe14connected to the foreign substance separation unit9is not especially limited, and may be downward in the vertical direction, in the horizontal direction, upward in the vertical direction or the like. In terms of preventing the inflow of the foreign substances13from settling on the bottom of the foreign substance separation unit9, it is preferable that the inlet of the medium supply pipe14connected to the foreign substance separation unit9is open in the horizontal or in the vertical upward direction.

The second pressure open/close means15has a function to open or close according to the decrease of the pressure inside the circulation path, so as to connect or disconnect the foreign substance sedimentation unit8and the foreign substance separation unit9via the medium supply pipe14. The pressure inside the circulation path when the second pressure open/close means15opens is not especially limited, and can be appropriately adjusted depending on the intended use of the circulation system1. In concrete terms, the second pressure open/close means15may be configured to open when the pressure inside the circulation path becomes a predetermined value or less. For example, in the case when the circulation system1is used for the vehicle cooling system, the pressure inside the circulation path can be freely adjusted depending on the type of the refrigerant12to be used, for example, but the second pressure open/close means15should open if the gauge pressure inside the circulation path becomes 0 kg/cm2or less.

According to the foreign substance removal apparatus7of the present embodiment, when the pressure inside the circulation path increases, the first pressure open/close means11enters the open state so as to connect the foreign substance sedimentation unit8and the foreign substance separation unit9via the foreign substance discharge pipe10, and when the pressure inside the circulation path decreases, the second pressure open/close means15opens so as to connect the foreign substance sedimentation unit8and the foreign substance separation unit9via the medium supply pipe14. Therefore unlike the first pressure open/close means11used for the foreign substance removal apparatus7of Embodiment 1, the first pressure open/close means11used for the foreign substance removal apparatus7of the present embodiment is only required to have a function to open in accordance with the increase of the pressure inside the circulation path, so as to connect the foreign substance sedimentation unit8and the foreign substance separation unit9via the foreign substance discharge pipe10. In concrete terms, the first pressure open/close means11may be configured to open when the pressure inside the circulation path becomes a predetermined value or more. The pressure inside the circulation path when the first pressure open/close means11opens is not especially limited, and may be appropriately adjusted depending on the intended use of the circulation system1. For example, in the case when the circulation system1is used for a vehicle cooling system, and a mixed solution containing water and ethylene glycol is used as the refrigerant12, the first pressure open/close means11opens if the gauge pressure inside the circulation path becomes 0.6 kg/cm2to 1.6 kg/cm2(preferably 0.9 kg/cm2to 1.3 kg/cm2). If the first pressure open/close means11is set to open at such pressure, the foreign substance removal effect can be implemented while maintaining the cooling performance of the cooling device3.

When the pressure inside the circulation path decreases, the second pressure open/close means15enters the open state, and a part of the refrigerant12stored in the foreign substance separation unit9is supplied to the foreign substance sedimentation unit8via the medium supply pipe14, hence the foreign substance discharge pipe10can be disposed near the bottom of the foreign substance separation unit9. Therefore the foreign substances13can be efficiently stored on the bottom of the foreign substance separation unit9.

In the foreign substance removal apparatus7having the above configuration, if the first pressure open/close means11enters the open state when the pressure inside the circulation path increases, the foreign substances13, inside the foreign substance sedimentation unit8, are discharged to the foreign substance separation unit9along with the refrigerant12, via the foreign substance discharge pipe10, whereby the pressure inside the circulation path can be decreased at the same time with the removal of the foreign substances13.

If the second pressure open/close means15enters the open state when the pressure inside the circulation path decreases, on the other hand, a part of the refrigerant12stored in the foreign substance separation unit9is supplied to the foreign substance sedimentation unit8via the medium supply pipe14, and the pressure inside the circulation path can be increased. At this time, the refrigerant12is supplied from the upper part of the foreign substance sedimentation unit8, therefore there is no possibility that the foreign substances13settled on the bottom of the foreign substance sedimentation unit8are stirred up. As a result, removal of the foreign substances13from the foreign substance sedimentation unit8and control of the pressure inside the circulation path can be efficiently performed.

According to the foreign substance removal apparatus7of the present embodiment, the foreign substances13can be even more efficiently removed from the foreign substance sedimentation unit8, in addition to the effects of the foreign substance removal apparatus7of Embodiment 1.

FIG. 8is an enlarged cross-sectional view depicting a liquid cyclone that is used for a foreign substance removal apparatus according to the present embodiment. The basic configuration of the foreign substance removal apparatus according to the present embodiment is the same as the foreign substance removal apparatus7according to Embodiments 1 and 2, except that a liquid cyclone is used for the foreign substance sedimentation unit8, hence only differences will be described.

InFIG. 8, a liquid cyclone30includes: a cyclone main unit33constituted by a cylindrical portion31and a conical portion32, the diameter of which gradually decreases downward from the bottom of the cylindrical portion31; a storage unit35which is disposed in an upper part of the cyclone main unit33, and is defined from inside the cyclone main unit33by a partition wall34; and a connection pipe36which is disposed on an axial center line of the vortex flow generated inside the cyclone main unit33, and connects the inside of the cyclone main unit33and the storage unit35. Further, a tubular inlet of the circulation pipe5is disposed in the cylindrical portion31of the cyclone main unit33, and a tubular outlet of the circulation pipe5is disposed in the storage unit35. The tubular inlet of the circulation pipe5, in particular, is preferably disposed in the tangential direction of the cylindrical portion31, in order to generate the swirling flow in the cyclone main unit33.

In the liquid cyclone30having the above structure, if the refrigerant12containing foreign substances13is introduced from the tubular inlet of the circulation pipe5to the cyclone main unit33, the refrigerant12flows down along the inner surface of the cyclone main unit33, becomes a swirling flow. Thereby a vortex flow is generated inside the cyclone main unit33, and the foreign substances13in the refrigerant12are separated by centrifugal force caused by this vortex flow. These foreign substances13are settled on the bottom of the cyclone main unit33. The vortex flow which moves down along the inner surface of the cyclone main unit33turns in an upward direction near the bottom of the cyclone main unit33. Thereby an upward vortex flow, moving toward the storage unit35, is generated on the axial center line of the cyclone main unit33. This upward vortex flow carries the refrigerant12after the foreign substances13separated, and this refrigerant12is guided to the storage unit35by the upward vortex flow, and is discharged from the tubular outlet of the circulation pipe5.

FIG. 8is an example of the structure of the liquid cyclone30, but the structure of the liquid cyclone30is not especially limited, as long as the structure allows for a cyclonic separation of the foreign substances13in the refrigerant12by generating a vortex flow in the refrigerant12introduced inside the liquid cyclone30.

According to the foreign substance removal apparatus7of the present embodiment, the foreign substances13can be even more efficiently removed from the foreign substance sedimentation unit8, in addition to the effects of the foreign substance removal apparatus7of Embodiment 1 and 2.

The present international application claims priority from Japanese Patent Application No. 2015-085988 filed on Apr. 20, 2015, and the entire content of which are hereby incorporated by reference.

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