Patent Publication Number: US-2009235686-A1

Title: Fluid temperature regulator

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a fluid temperature regulator which cools/warms fluid such as blood to a desired temperature. 
     As a related-art fluid temperature regulator of this kind, there is a regulator (a first related-art regulator) in which, as indicated by the schematic plan and side configurations shown in  FIGS. 7A and 7B , an extracorporeal circulation blood circuit  41  is sandwiched between a metallic plate  42  and a heat insulating material  43 , and blood in the extracorporeal circulation blood circuit  41  is cooled/warmed through the metallic plate  42  by a cooling/warming apparatus  44  (see JP-A-09-602). 
     In the first related-art regulator, however, the heat capacity must be increased by enlarging (thickening) the metallic plate  42  so that blood in the extracorporeal circulation blood circuit  41  is prevented from being broken by a sudden drop or rise in temperature, and the performance must be improved by using a higher-power cooling/warming apparatus  44 . Therefore, the shape and weight of the regulator are increased, and furthermore the production cost is raised. The cooling/warming is performed from one face of the extracorporeal circulation blood circuit  41 , and hence there is a problem in that the heat transfer efficiency is poor. 
     There is another related-art fluid temperature regulator (a second related-art regulator) in which, as shown in schematic plan and side views of  FIGS. 8A and 8B , an extracorporeal circulation blood circuit  41  is sandwiched between metallic plates  42 - 1 ,  42 - 2 , and blood in the extracorporeal circulation blood circuit  41  is cooled/warmed through the metallic plates  42 - 1 ,  42 - 2  by two cooling/warming apparatuses  44 - 1 ,  44 - 2  (see JP-A-2004-148027). 
     In the second related-art regulator, the heat transfer efficiency is superior to the first related-art regulator, but it is required to use the two cooling/warming apparatuses  44 - 1 ,  44 - 2 , thereby producing a problem in that the configuration grows in size and the production cost is raised. 
     In both the first and second related-art regulators, as the metallic plate  42  and the blood in the extracorporeal circulation blood circuit  41  are further separated from the portions where they are in contact with the cooling/warming apparatus  44 , they are less thermally affected by the cooling/warming apparatus  44 . Therefore, a temperature bias is caused and the heat transfer efficiency is reduced. 
     There is a related-art fluid temperature regulator (a third related-art regulator) in which, as indicated by the schematic plan configuration shown in  FIG. 9 , an extracorporeal circulation blood circuit  41  is immersed in a circulation medium  46  in a refrigerant tank  47  the temperature of which is regulated by a thermal regulator  45 , thereby cooling/warming blood in the extracorporeal circulation blood circuit  41  (see JP-A-2002-119586 and JP-A-2007-151696) A third related-art regulator corresponding to one of the related-art fluid temperature regulators is disclosed in JP-A-2002-119586. A fourth related-art regulator corresponding to the other is disclosed in JP-A-2007-151696. 
     In the third related-art regulator, when a damage occurs in a portion of the extracorporeal circulation blood circuit  41  where the extracorporeal circulation blood circuit  41  is in direct contact with the circulation medium  46 , there is a fear that the circulation medium  46  flows into the extracorporeal circulation blood circuit  41 , In a related art disclosed in JP-A-2002-119586, the thermal regulator  45  and the refrigerant tank  47  must be disposed, and hence there is a problem in that the regulator grows in size. In a related art disclosed in JP-A-2007-151696, the refrigerant is not stirred, and hence a thermal gradient is produced in the refrigerant tank  47 , thereby producing a problem in that the heat transfer efficiency with the blood is poor. 
     SUMMARY 
     It is therefore an object of the invention to provide a fluid temperature regulator in which the size and cost of the configuration are not increased, the heat transfer efficiency is high, and, even when a damage occurs in a transfusion circuit, a medium does not flow into the transfusion circuit so that the safety level is high. 
     In order to achieve the object, according to the invention, there is provided a fluid temperature regulator, comprising:
         a case, containing a refrigerant;   a cooling/warming device, configured to cool/warm the case; and   a storage, including an opening through which a circuit for transfusing fluid is to be inserted/removed, the storage configured to house the circuit inserted through the opening and be in contact with the circuit, the storage being surrounded by the refrigerant and watertight for the refrigerant in the case.       

     The fluid temperature regulator may further include: a stirrer, configured to stir the refrigerant is provided in the case. 
     The fluid temperature regulator may further include: a guide, configured to guide the refrigerant to a face of the storage, the refrigerant being in contact with the face of the storage. 
     The guide may include a flow path through which the refrigerant spirally flows around the storage. 
     The stirrer may guide the refrigerant to the guide. 
     The storage nay be comprised of a heat-conducting material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         FIG. 1  is a perspective view showing a first embodiment of the fluid temperature regulator of the invention. 
         FIG. 2  is a section view taken along line A-A in a state where a transfusion circuit in  FIG. 1  is housed in a storage. 
         FIG. 3  is a view showing a combination of a section view taken along line B-B in the state where the transfusion circuit in  FIG. 1  is housed in the storage, and a functional block diagram of temperature adjustment. 
         FIG. 4  is a section view taken along line B-B in the state where the transfusion circuit in  FIG. 1  is housed in the storage, showing the temperature difference between fluid in the transfusion circuit and a refrigerant by means of the size of an arrow. 
         FIG. 5  s a section view of a second embodiment of the fluid temperature regulator of the invention, taken along a line segment which is identical with line A-A in  FIG. 1 . 
         FIG. 6  s a section view of the second embodiment of the fluid temperature regulator of the invention, taken along a line segment which is identical with line B-B in  FIG. 1 . 
         FIG. 7A  is a schematic view showing a plan configuration of the first related-art regulator, and  FIG. 7B  is a schematic view showing a side configuration. 
         FIG. 8A  is a schematic view showing a plan configuration of the second related-art regulator, and  FIG. 8B  is a schematic view showing a side configuration. 
         FIG. 9  is a schematic view showing a plan configuration of the third related-art regulator. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinafter embodiments of the fluid temperature regulator of the present invention will be described with reference to the accompanying drawings. In the figures, the identical components are denoted by the same reference numerals, and duplicated description will be omitted.  FIG. 1  is a perspective view showing a first embodiment of the fluid temperature regulator. In the fluid temperature regulator, for example, a refrigerant  11  shown in  FIG. 2  and the like is filled in a refrigerant case  10  made from a metal which is a good heat-conducting material, such as copper or stainless steel. As the refrigerant  11 , water, antifreezing fluid, or the like may be used. 
     An opening  12  which is for example laterally elongated is formed in one wall face of the refrigerant case  10  so that a transfusion circuit  21  for transfusing fluid such as blood is insertable/removable. A cooling/warming unit  31  which is configured by Peltier element is bonded to, for example, the lower wall of the refrigerant case  10  which stands as shown in  FIG. 1 , and configured so that the refrigerant  11  in the refrigerant case  10  is cooled/warmed by the cooling/warming unit  31 . 
       FIG. 2  is a section view taken along line A-A of  FIG. 1 , and  FIG. 3  is a section view taken along line B-B. Both FIGS.  2  and  3  show a state where the transfusion circuit  21  is inserted into a storage  13  through the opening  12 . The storage  13  which communicates with the opening  12  is made from a metal or metal alloy which is a good heat-conducting material, and watertight for the refrigerant  11 . 
     The storage  13  is disposed at a point substantially intermediate of the height of the refrigerant case  10 , and has a size which can house a required portion of the transfusion circuit  21 . The required portion means a portion where a tube  22  constituting the transfusion circuit  21  is meanderingly bent, or that corresponding to the bag member in JP-A-09-602 above. Preferably, the transfusion circuit  21  is in contact with all of the walls of the storage  13  so that heat exchange between the refrigerant  11  surrounding the storage  13  and the fluid in the transfusion circuit  21  is performed. 
     A stirring unit  14  for stirring the refrigerant  11  is disposed in the refrigerant case  10 . The stirring unit is configured by, for example, a pump. In the embodiment, the stirring unit  14  is placed on the bottom face in the lower end of the wall face opposed to that where the opening  12  is formed, so that all of the refrigerant  11  including portions which are above and below the storage  13  can be satisfactorily stirred. 
     The fluid in the transfusion circuit  21  is sent by, for example, an infusion pump which is not shown, and flows in the directions of the arrows S 1 , S 2  in  FIG. 2 . In order to perform temperature adjustment by the cooling/warming unit  31 , temperature sensors  32  are disposed on the tube  22  in the vicinity of the opening  12 . In the embodiment, the temperature sensors  32  are disposed on a portion of the tube  22  where the fluid flows into the storage  13 , and that of the tube  22  where the fluid flows out from the storage  13 , respectively. 
     Signals from the temperature sensors  32  are supplied to a control portion  40  to be used as temperature data. Preset temperature information is given to the control portion  40 . The control portion  40  performs an electric power control in accordance with the difference between the preset temperature information and the temperature data which are obtained as described above, on the cooling/warming unit  31 , thereby adjusting the temperature. 
     In the thus configured fluid temperature regulator, the temperature adjustment is performed by the cooling/warming unit  31  in the state where the transfusion circuit  21  is inserted through the opening  12  and housed in the storage  13 . Furthermore, all of the refrigerant  11  is stirred by the stirring unit  14 , and the temperature of the refrigerant  11  in the refrigerant case  10  is equalized. The heat of the refrigerant  11  is transmitted to the fluid in the transfusion circuit  21  through the walls of the storage  13 . Therefore, highly efficient heat exchange occurs, so that the temperature of the whole refrigerant  11  and that of the fluid in the transfusion circuit  21  are rapidly equalized. 
     Therefore, it is possible to realize highly efficient heat exchange which is similar to that in the configuration of the related art shown in  FIG. 8  where the transfusion circuit is sandwiched by the two metallic plates and the temperature is adjusted by using the two cooling/warming apparatuses. Moreover, only one cooling/warming apparatus is required, and hence the space saving can be achieved together with the cost reduction. 
     Furthermore, uniformalization of the temperature of the refrigerant  11  in the refrigerant case  10  can be realized, and the heat exchange is performed through the walls of the storage  13 . As indicated by the sizes of the arrows in  FIG. 4 , therefore, the temperature difference between the fluid in the transfusion circuit  21  and the refrigerant  11  is uniform irrespective of positional differences. Consequently, it is possible to prevent a risk that the fluid (for example, blood) is locally cooled/warmed to apply extra stress to the fluid of the portion, from occurring. 
     Next,  FIGS. 5 and 6  show a second embodiment of the fluid temperature regulator of the invention. The fluid temperature regulator of the embodiment has a configuration where a continuous partition plate  50  is disposed to partition the space between the inner wall face  10   a  of the refrigerant case  10  and the outer wall face  13   a  of the storage  13 . For example, the partition plate  50  is made from the same good heat-conducting material (such as copper or stainless steel) as the storage  13 , whereby the heat transfer efficiency can be improved. The form obtained by connecting together portions where the inner wall face  10   a  of the refrigerant case  10  and the outer wall face  13   a  of the storage  13  are joined to the partition plate  50  has a spiral shape centered at the storage. 
     The region which is surrounded by the inner wall face  10   a  of the refrigerant case  10 , the outer wall face  13   a  of the storage  13 , and the partition plate  50  forms a passage  51  which is continuous from the side of the opening  12  to the face opposite to the opening  12 , thereby forming a flow path. The start end  52  and the terminal end  53  of the passage  51  are communication with each other by a pipe  54 , The pipe  54  is passed through the partition plate  50 , and the passed portions are sealed. The stirring unit  14  is disposed in the terminal end  53  of the passage  51 , and configured so as to send the refrigerant  11  which comes through the passage  51 , into the pipe  54 . Namely, the stirring unit  14  is configured so as to guide the refrigerant  11  from the terminal end  53  of the passage  51  to the start end  52  of the passage  51  which is formed by the partition plate  50 . Furthermore, the partition plate  50  corresponds to a guiding unit for guiding the refrigerant  11  to the face of said storage  13  which is on the side of the refrigerant  11  and with which the refrigerant  11  is in contact. 
     Also in the embodiment, the signals detected by the temperature sensors  32  are supplied to the control portion  40  to he used as temperature data, to be given to the control portion  40 . Also in the embodiment, the control portion  40  performs an electric power control in accordance with the difference between the preset temperature information and the temperature data which are obtained as described above, on the cooling/warming unit  31 , thereby adjusting the temperature. 
     In the thus configured fluid temperature regulator, the refrigerant  21  which is fed into the pipe  54  with stirring by the stirring unit  14  reaches the start end  52  of the passage  51  through the pipe  54 , and further flows through the pipe  54  to reach the terminal end  53 . Then, the refrigerant  11  is sent into the pipe  54  with stirring by the stirring unit  14 , and circulates through a path similar to that described above. 
     In the circulation process, in the passage  51 , the refrigerant  11  flows in a state where the refrigerant is always in contact with the outer wall face  13   a  of the storage  13  to perform heat exchange. Furthermore, the refrigerant  11  receives cooling/warming by the cooling/warming unit  31 . Namely, the refrigerant  11  always performs heat exchange with the transfusion circuit  21  through the outer wall face  13   a  of the storage  13 , while receiving cooling/warning by the cooling/warming unit  31 . The fluid in the transfusion circuit  21  can be efficiently cooled/warmed by the refrigerant  11  the temperature of which is uniformalized by the flow. The temperature adjustment can be performed very adequately. 
     In the above, the configuration where the pipe  54  and the stirring unit  14  are disposed inside the refrigerant case  10  is employed. Alternatively, a configuration where the pipe  54  and/or the stirring unit  14  are disposed outside the refrigerant case  10  may be employed. The shape of the passage  51  is not restricted to a spiral shape. For example, the space between the inner wall face  10   a  of the refrigerant case  10  and the outer wall face  13   a  of the storage  13  may be partitioned by a plurality of annular partition plates, and communication ports are formed in the partition plates to configure a passage which is continuous from the side of the opening  12  to the face opposite to the opening  12 . 
     Also in the configuration of the modification, it is possible to achieve the effect that the temperature of the fluid in the transfusion circuit  21  can be adjusted very adequately by the refrigerant  11  the temperature of which is uniformalized by the flow in the passage. 
     According to an aspect of the invention, the fluid temperature regulator includes a storage that has an opening through which a transfusion circuit for transfusing fluid is to be inserted/removed, that houses the transfusion circuit inserted through the opening, while being in contact with the transfusion circuit, that is surrounded by a refrigerant, and that is watertight for the refrigerant. Even when a damage occurs in the transfusion circuit, since the transfusion circuit exists in the storage that is watertight for the refrigerant, there is no fear that the medium flows into the transfusion circuit. The storage is surrounded by the refrigerant, and a refrigerant case which contains the refrigerant is cooled/warmed. Therefore, heat is gradually transferred, so that, in the case where the fluid is blood, the blood is not exposed to a temperature which is so high or low that the blood may be damaged, and a high safety level can be ensured. Heat is uniformly transferred from the refrigerant to the whole storage. Therefore, the temperature of the fluid can be efficiently adjusted. 
     According to an aspect of the invention, a thermal gradient is not produced in the refrigerant of the refrigerant case, and the heat transfer efficiency with the blood can be improved. 
     According to an aspect of the invention, the refrigerant is guided to the face of the storage on the side of the refrigerant by the guiding unit, so that a flow is produced in the refrigerant. Consequently, the refrigerant in the refrigerant case can be maintained more efficiently to a uniform temperature, and the heat transfer efficiency with the blood can be improved. 
     According to an aspect of the invention, the refrigerant is guided to a flow path through which the refrigerant can spirally flow around the storages so that a flow is produced in the refrigerant. Consequently, the refrigerant in the refrigerant case can be maintained more efficiently to a uniform temperature, and the heat transfer efficiency with the blood can be improved. 
     According to an aspect of the invention, a flow passing through the stirring unit and the guiding unit is produced in the refrigerant. Consequently, the refrigerant in the refrigerant case can be maintained more efficiently to a uniform temperature, and the heat transfer efficiency with the blood can be improved. 
     According to an aspect of the invention, the refrigerant and the transfusion in the transfusion circuit can perform highly efficient heat exchange with each other through the storage which is configured by a good heat-conducting material.