Constant temperature liquid circulating apparatus

The whole main tank for housing the constant temperature liquid the temperature of which is adjusted by a temperature adjusting device is supported in a sub tank with a gap as a heat insulating layer around the main tank. A liquid level regulating mechanism supplies and discharges the constant temperature liquid between inside of the main tank and the gap formed in the sub tank to thereby achieve heat insulation and regulation of the liquid level of the constant temperature liquid housed in the main tank by utilizing the same gap in the sub tank.

TECHNICAL FIELD

The present invention relates to a circulating apparatus for supplying a constant temperature liquid to a load in a circulating manner in a case of cooling a heat load with the constant temperature liquid, for example.

BACKGROUND ART

In cooling a load, for example, with this type of circulating apparatus, a coolant as a constant temperature liquid a temperature of which is adjusted is housed in a tank and the coolant is supplied to the load through piping by a pump in a circulating manner to thereby cool the load. The coolant the temperature of which rises due to cooling of the load and which flows back into the tank exchanges heat with a refrigerant in a heat exchanger to thereby adjust the temperature.

The load is normally connected to the circulating apparatus through piping prepared by a user. A kind, a disposition place, and the like of the load are different depending on users. Therefore, if flow path capacities in the piping and the load are large, a liquid level in the tank may lower by a large amount when operation of the circulating apparatus starts to supply the coolant to the piping and the heat load. In some cases, there is a fear that the reduction in the liquid level in the tank provides a hindrance to operation of the pump.

On the other hand, it is preferable to recover all the coolant filling the load and the piping connecting the apparatus and the load into the tank when the operation of this circulating apparatus is completed or at the time of maintenance, inspection, or the like of the apparatus. However, if the coolant of such an amount that a proper liquid level is obtained in the tank in a steady operating state of the apparatus has been used, all the coolant may not be housed in the tank and the coolant may overflow from the tank in recovering the coolant depending on the flow path capacities in the piping and the load.

Therefore, in order to solve such problems, there is an apparatus in which a liquid level regulating chamber is provided in a tank and communicates through a bottom portion thereof with inside of the tank, compressed gas is supplied to and discharged from the liquid level regulating chamber to cause a constant temperature liquid to flow out from the liquid level regulating chamber into the tank or flow from the tank into the liquid level regulating chamber to thereby regulate a liquids level of the constant temperature liquid in the tank as disclosed in Japanese Patent Application Laid-open No. 2002-181427 (JP-A).

This circulating apparatus has advantages that the liquid level of the constant temperature liquid in the tank does not change by a large amount when the operation starts or is completed and that a small amount of constant temperature liquid can efficiently be utilized.

PROBLEMS TO BE SOLVED BY THE INVENTION

However, in the circulating apparatus disclosed in JP-A 2002-181427, it is necessary to provide a heat insulator around the tank so as to heat-insulate the constant temperature liquid the temperature of which is adjusted and which is housed in the tank. As a result, the apparatus increases in size and weight to thereby increase a cost of manufacturing.

The present invention has been accomplished to solve the above problems and it is an object of the invention to provide a constant temperature liquid circulating apparatus for achieving heat insulation and regulation of a liquid level of a constant temperature liquid a temperature of which is adjusted and which is housed in the tank by utilizing the same gap formed around the tank to thereby eliminate a heat insulator from the tank, the whole apparatus being able to be reduced in size and weight to thereby suppress a cost of manufacturing.

METHOD TO SOLVE THE PROBLEM

To achieve the above object, according to the invention, there is provided a constant temperature liquid circulating apparatus comprising: a main tank for housing a constant temperature liquid a temperature of which is adjusted, the main tank having a bottom and closed with a lid; a sub tank in which the whole main tank is disposed, the sub tank having a bottom and closed with a lid; a feed pipe and a return pipe for connecting the main tank and a load to which the constant temperature liquid is to be supplied; and a circulating pump for supplying the constant temperature liquid to the load through these feed pipe and return pipe in a circulating manner, wherein the main tank is supported in the sub tank with a gap as a heat insulating layer around the main tank and a liquid level regulating mechanism for regulating a liquid level in the main tank by supplying and discharging the constant temperature liquid between inside of the main tank and the gap in the sub tank is provided.

Thus, heat insulation and regulation of the liquid level of the constant temperature liquid housed in the main tank can be achieved by utilizing the same gap formed between the main tank and the sub tank.

Here, the sub tank is preferably provided with a liquid discharge mechanism for discharging the constant temperature liquid housed in the gap in the sub tank outside. Thus, it is possible to discharge the constant temperature liquid remaining in the gap in the sub tank outside during steady operation of the circulating apparatus to thereby prevent reduction of a heat insulating effect of the gap.

To put is concretely, the liquid discharge mechanism has a discharge hole formed in a bottom portion of the sub tank and opened and closed by a first valve. By opening the valve to open the discharge hole, the constant temperature liquid can be discharged outside the sub tank.

The main tank is preferably provided with first liquid level sensing means for sensing the liquid level of the constant temperature liquid housed in the main tank, the sub tank is preferably provided with second liquid level sensing means for sensing a liquid level of the constant temperature liquid housed in the gap in the sub tank, and the liquid discharge mechanism preferably discharges the constant temperature liquid housed in the gap in the sub tank outside when the first liquid level sensing means senses that the liquid level in the main tank is equal to or higher than a predetermined lowest liquid level and the second liquid level sensing means senses that the liquid level in the sub tank is equal to or higher than a predetermined liquid level.

According to one aspect of the constant temperature liquid circulating apparatus of the invention, the liquid level regulating mechanism has a discharge hole provided to an upper portion of the main tank to allow the constant temperature liquid housed in the main tank to overflow into the gap in the sub tank and a regulating pump for supplying the constant temperature liquid housed in the gap in the sub tank into the main tank.

At this time, it is preferable that the discharge hole is formed in a side wall of the main tank and has a second valve for opening and closing the discharge hole.

According to another aspect, the liquid level regulating mechanism has a regulating pump for supplying and discharging the constant temperature liquid between inside of the main tank and the gap in the sub tank.

According to yet another aspect, the liquid level regulating mechanism has a gas supply source for supplying compressed gas to the gap in the sub tank and a supply/discharge hole formed in a bottom portion of the main tank and opened and closed by a third valve, the mechanism regulating the liquid level in the main tank by regulating pressure in the gap in the sub tank to supply and discharge the constant temperature liquid between the inside of the main tank and the gap in the sub tank through the supply/discharge hole.

With the constant temperature liquid circulating apparatus according to the invention, the whole main tank for housing the constant temperature liquid the temperature of which is adjusted is supported in the sub tank with the gap as the heat insulating layer around the main tank and the liquid level regulating mechanism can supply and discharge the constant temperature liquid between inside of the main tank and the gap formed in the sub tank. Therefore, it is possible to achieve heat insulation and regulation of the liquid level of the constant temperature liquid housed in the main tank by utilizing the same gap in the sub tank. As a result, the heat insulator can be eliminated from the main tank and the whole apparatus can be reduced in size and weight to thereby suppress the cost of manufacturing.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1shows a first embodiment of a constant temperature liquid circulating apparatus according to the present invention. The circulating apparatus includes a main tank2for housing a constant temperature liquid1a temperature of which is adjusted, a sub tank3in which the whole main tank2is disposed and the constant temperature liquid1is similarly housed, a feed pipe5and a return pipe6connecting the main tank2and a load4to which the constant temperature liquid1is to be supplied, a circulating pump7for supplying the constant temperature liquid1to the load4through these feed pipe5and return pipe6in a circulating manner, and a temperature adjusting means8for adjusting the temperature of the constant temperature liquid1which has returned from the load4.

The main tank2is formed of a cylindrical side wall2a, a bottom plate2bfor closing a lower end of the side wall2ato form a bottom of the main tank2, and a lid plate2cfor closing an upper end of the side wall2aand has a structure having the bottom and closed with the lid. To the main tank2, the feed pipe5for feeding the constant temperature liquid1to the load4and the return pipe6for allowing the constant temperature liquid1to flow back to the main tank2from the load4are connected. On the feed pipe5, the circulating pump7is provided. Provided on the return pipe6is the temperature adjusting means8formed of a heat exchanger, a heater, and the like, for example, for adjusting the temperature of the constant temperature liquid1which has given and received heat to and from the load4to a proper set temperature. The circulating pump7may be a submerged pump and the temperature adjusting means8may be provided in the main tank2.

On the other hand, the sub tank3is formed of a cylindrical side wall3a, a bottom plate3bfor closing a lower end of the side wall3ato form a bottom of the sub tank3, and a lid plate3cfor closing an upper end of the side wall3aand has a structure having the bottom and closed with the lid, similar to the main tank2. A height of the side wall3aof the sub tank3and sizes of the bottom plate3band the lid plate3care greater than those of the main tank2so that the whole main tank2can be housed in the sub tank3. Moreover, at an upper portion of the sub tank3, an injection hole3dfor injecting the constant temperature liquid1into the sub tank3is provided and can be opened and closed by a cap3e.

In the sub tank3, the main tank2is supported by proper means with a gap9functioning as a heat insulating layer existing between an outer face of the main tank2and an inner face of the sub tank3. With this gap9formed throughout a periphery of the main tank2and between the sub tank3and the main tank2, it is possible to heat-insulate the constant temperature liquid1the temperature of which is adjusted by the temperature adjusting means8and which is housed in the main tank2.

At the same time, in the circulating apparatus of the present embodiment, by a liquid level regulating mechanism which will be described later, the constant temperature liquid1is supplied and discharged and moved between an inside of the main tank2and the gap9in the sub tank3. In this way, in recovering the constant temperature liquid1filling the flow path in the load4, the feed pipe5, and the return pipe6, for example, the constant temperature liquid1which is too much to be housed in the main tank2can be housed in the gap9in the sub tanks3or the constant temperature liquid1housed in the gap9in the sub tank3can be supplied into the main tank2so as to prevent hindrance of the operation of the circulating apparatus by the reduction in the liquid level in the main tank2when the operation of the circulating apparatus starts to thereby regulate the liquid level in the main tank2.

In this manner, because the whole main tank2for housing the constant temperature liquid1the temperature of which is adjusted is supported in the sub tank3with the gap9as the heat insulating layer existing around the main tank2and because the constant temperature liquid1can be supplied and discharged between the inside of the main tank2and the gap9formed in the sub tank3by the liquid level regulating mechanism, heat insulation and regulation of the liquid level of the constant temperature liquid1housed in the main tank2can be achieved by utilizing the same gap9in the sub tank3. As a result, it is possible to eliminate the heat insulator which has conventionally been used from the main tank2to thereby reduce the whole circulating apparatus in size and weight to suppress the cost of manufacturing. Moreover, because an operation for separating the heat insulator is unnecessary at the time of disposal of the apparatus, a cost of disposal can be suppressed.

Furthermore, the sub tank3is provided with a liquid discharge mechanism10for discharging the constant temperature liquid1housed in the gap9in the sub tank3outside. To put it concretely, the liquid discharge mechanism10is formed of a discharge hole10aformed in a position of the side wall3aof a bottom portion of the sub tank3and lower than a bottom face of the main tank2and a first valve10bfor opening and closing the discharge hole10a. The discharge hole10amay be formed in the bottom plate3bof the sub tank3. The constant temperature liquid1housed in the gap9in the sub tank3reduces the heat insulating effect of the gap9. However, after the operation of the circulating apparatus starts, when the constant temperature liquid1is distributed throughout the flow path in the load4, the feed pipe5, and the return pipe6and the constant temperature liquid1of the proper liquid level is kept in the main tank2(seeFIG. 3(d)), i.e., during the steady operation, by opening the first valve10bto open the discharge hole10aand discharging the constant temperature liquid1remaining in the gap9in the sub tank3outside, it is possible to prevent reduction in the heat insulating effect of the gap9.

The load4is a heat load, for example. In this case, the constant temperature liquid1is a coolant. As the coolant as the constant temperature liquid1, completely fluorinated liquid, pure water, ethylene glycol, or the like is used, for example.

The liquid level regulating mechanism specifically includes a discharge hole11aopened and closed by a second valve11bformed at the side wall2aof an upper portion of the main tank2and a regulating pump12provided on a supply pipe12aconnecting the inside of the main tank and the gap in the sub tank. By opening the second valve11bto open the discharge hole11a, the constant temperature liquid1housed in the main tank2can overflow into the gap9in the sub tank3. Furthermore, by driving the regulating pump12, the constant temperature liquid1housed in the gap9in the sub tank3is drawn up from the bottom portion of the sub tank3through the supply pipe12aand supplied to the upper portion of the main tank2. Here, the regulating pump12may be a submerged pump.

The main tank2is provided with a first liquid level sensing means13for sensing the liquid level of the constant temperature liquid1housed in the main tank2and the sub tank3is provided with a second liquid level sensing means14for sensing the liquid level of the constant temperature liquid1housed in the gap9in the sub tank3. To put it concretely, the first liquid level sensing means13is formed of a level sensor A disposed in a position in the main tank2and lower than the discharge hole11aand at a height corresponding to the lowest liquid level of the main tank2and a level sensor B disposed in a position in the main tank2and higher than the discharge hole11aand at a height corresponding to the highest liquid level of the main tank2. On the other hand, the second liquid level sensing means14is formed of a level sensor C disposed in a position in the bottom portion of the sub tank3and higher than the discharge hole10aand in a position lower than the bottom face of the main tank2. The respective liquid level sensing means13and14are not limited to the above-described level sensors but may be level switches or anything that can sense the liquid level.

If the first liquid level sensing means13senses that the liquid level in the main tank2is lower than the predetermined lowest liquid level and the second liquid level sensing means14senses that the liquid level in the sub tank3is equal to or higher than the predetermined liquid level, i.e., if the constant temperature liquid1is not sensed by the level sensor A and the constant temperature liquid1is sensed by the level sensor C, the regulating pump12is driven to supply the constant temperature liquid1from the gap9in the sub tank3into the main tank2.

If the first liquid level sensing means13senses that the liquid level in the main tank2is equal to or higher than the predetermined highest liquid level, i.e., if the constant temperature liquid1is sensed by the level sensor B, the second valve11bis opened to discharge the constant temperature liquid1overflowing the main tank2into the gap9in the sub tank3through the discharge hole11a. It is also possible that the second valve11bis opened and closed manually and an alarm is given to urge the opening operation.

During the above-described steady operation of the circulating apparatus, if the first liquid level sensing means13senses that the liquid level in the main tank2is equal to or higher than the predetermined lowest liquid level and the second liquid level sensing means14senses that the liquid level in the sub tank3is equal to or higher than the predetermined liquid level, i.e., if the constant temperature liquid1is sensed simultaneously by the level sensor A and the level sensor C, the discharge hole10ais opened by the first valve10bto discharge the constant temperature liquid1housed in the gap9in the sub tank3outside.

Moreover, if the first liquid level sensing means13senses that the liquid level in the main tank2is lower than the predetermined lowest liquid level and the second liquid level sensing means14senses that the liquid level in the sub tank3is lower than the predetermined liquid level, i.e., if neither of the level sensors A and C senses the constant temperature liquid1, an alarm is given to urge replenishing of the gap9with the constant temperature liquid1through the injection hole3dof the sub tank3.

Here, as shown inFIG. 4, it is also possible that an auxiliary tank15in which the constant temperature liquid1is housed is connected from outside to the sub tank3through a third valve15aand that the third valve15ais opened to replenish the gap9in the sub tank3with the constant temperature liquid1from the auxiliary tank15when neither of the level sensors A and C senses the constant temperature liquid1. It is also possible that the third valve15ais opened and closed manually and that an alarm is given to urge the opening operation of the third valve15a.

Next, operation of the constant temperature liquid circulating apparatus according to the first embodiment will be described in detail based onFIGS. 2 and 3.

First, when the operation starts, as shown inFIG. 2, the constant temperature liquid1is injected into the gap9in the sub tank3from the injection hole3d. In a state in which the constant temperature liquid1is sensed by the level sensor C and not sensed by the level sensor A, the regulating pump12is driven to draw up the constant temperature liquid1from the gap9in the sub tank3into the main tank2until the sensor A senses the constant temperature liquid1. At this time, an extra amount of constant temperature liquid1to be, sent into the flow path in the load4, the feed pipe5, and the return pipe6is injected into the sub tank3(FIG. 2(a)).

Then, if the circulating pump7is driven, the constant temperature liquid1in the main tank2is sent from the feed pipe5into the flow path in the load4and the return pipe6in order and, as a result, the liquid level in the main tank2reduces and the level sensor A does not sense the constant temperature liquid1. Then, the regulating pump12is driven to draw up the constant temperature liquid1in the sub tank3into the main tank2(FIGS. 2(b) to2(d)). At this time, the constant temperature liquid1which is finally left in the sub tank3is discharged outside the sub tank3from the discharge hole10aby opening the first valve10b.

Next, during the steady operation, the constant temperature liquid1the temperature of which is adjusted by the temperature adjusting means8is supplied by the circulating pump7from the main tank2to the load4through the feed pipe5and the return pipe6in the circulating manner and, at the same time, the constant temperature liquid1the temperature of which is adjusted and which is housed in the main tank2is heat-insulated by the heat insulating effect of the gap9in the sub tank3.

When the completely fluorinated liquid a volume of which changes by a large amount depending on the temperature is used as the constant temperature liquid1, if a set temperature of the constant temperature liquid1is changed to a higher temperature by the temperature adjusting means8and the temperature of the constant temperature liquid1increases to a higher temperature, the volume of the constant temperature liquid1increases. Therefore, if the constant temperature liquid1in the main tank2is sensed by the level sensor B during the steady operation, the second valve11bis opened to allow the constant temperature liquid1to overflow through the discharge hole11ainto the gap9in the sub tank3. Then, when the constant temperature liquid1in the sub tank3is sensed by the level sensor C, the first valve10bis opened to discharge the constant temperature liquid1outside the sub tank3through the discharge hole10a. When the constant temperature liquid1is not sensed by the level sensor B, the second valve11bis closed.

On the other hand, when the set temperature of the constant temperature liquid1is changed to a lower temperature by the temperature adjusting means8and the temperature of the constant temperature liquid1reduces to a lower temperature, the volume of the constant temperature liquid1reduces. Therefore, when the constant temperature liquid1in the main tank2is not sensed by the level sensor A during the steady operation, an instruction to replenish the sub tank3by adding a necessary amount of constant temperature liquid1is provided. Then, if the replenished constant temperature liquid1is sensed by the level sensor C, the liquid1is drawn up by the regulating pump12and supplied to the main tank2until the liquid1is sensed by the level sensor A. At this time, the constant temperature liquid1which is finally left in the sub tank3is discharged outside the sub tank3through the discharge hole10aby opening the first valve10b.

In recovering the constant temperature liquid1into the tanks2,3when the operation is completed, the temperature of the constant temperature liquid1is first adjusted by the temperature adjusting means8to a higher temperature than a dew-point temperature in the room so as to prevent occurrence of condensation. Then, as shown inFIG. 3, the constant temperature liquid1filling the flow path in the load4, the feed pipe5, and the return pipe6is recovered into the main tank2by air purge or the like. When the liquid level in the main tank2increases (FIG. 3(b)) and the constant temperature liquid1is sensed by the level sensor B, the second valve11bis opened to cause the constant temperature liquid1to overflow through the discharge hole11ainto the gap9in the sub tank3(FIG. 3(c)). When the recovery of the constant temperature liquid1is completed and it is recognized that the constant temperature liquid1is not sensed by the level sensor B, the second valve11bis closed (FIG. 3(d)). If the liquid level of the sub tank3reaches the height of the second valve11bbefore the recovery is completed, it is preferable that the level sensor B senses an abnormal condition of the liquid level and gives an alarm.

FIGS. 5 to 7show second to fourth embodiments of the constant temperature liquid circulating apparatus according to the invention. Here, in order to avoid overlaps, detailed descriptions of the component parts similar to those of the first embodiment will be omitted.

First, in the second embodiment shown inFIG. 5, the liquid level regulating mechanism includes a discharge hole16formed in a position of the side wall2aof the upper portion of the main tank2and at a height corresponding to the highest liquid level of the constant temperature liquid1and the submerged pump as the regulating pump12. Through the discharge hole16, inside of the main tank2and the gap9in the sub tank3always communicate with each other. Therefore, in the present embodiment, the second valve11bin the first embodiment is omitted.

Next, in the third embodiment shown inFIG. 6, the liquid level regulating mechanism includes the regulating pump12for supplying and discharging the constant temperature liquid1between inside of the main tank2and the gap9in the sub tank3and an end portion on the main tank2side of a supply pipe12aconnected to the regulating pump12is open in a position at a height corresponding to the highest liquid level of the main tank2. Therefore, in the present embodiment, the discharge hole11aand the second valve11bin the first embodiment are omitted.

Furthermore, in the fourth embodiment shown inFIG. 7, the liquid level regulating mechanism includes a gas supply source17for supplying compressed gas to the gap9in the sub tank3and a supply/discharge hole18aformed in the side wall2aof the bottom portion of the main tank2to be opened and closed by a third valve18b. By regulating pressure of the gap9in the sub tank3to supply and discharge the constant temperature liquid1between the inside of the main tank2and the gap9in the sub tank3through the supply/discharge hole18a, the liquid level in the main tank2can be regulated. As the circulating pump7, a submerged pump is employed. Therefore, in the present embodiment, the regulating pump12, the discharge hole11a, and the second valve11bin the first embodiment are omitted. The supply/discharge hole18amay be provided in the bottom plate2bof the main tank2.